Re: [DISCUSS] KIP-405: Kafka Tiered Storage

[Jun Rao <ju...@confluent.io>]

Hi, Satish,

Thanks for the updated KIP. A few more comments below.

605.2 "Build the local leader epoch cache by cutting the leader epoch
sequence received from remote storage to [LSO, ELO]." I mentioned an issue
earlier. Suppose the leader's local start offset is 100. The follower finds
a remote segment covering offset range [80, 120). The producerState with
this remote segment is up to offset 120. To trim the producerState to
offset 100 requires more work since one needs to download the previous
producerState up to offset 80 and then replay the messages from 80 to 100.
It seems that it's simpler in this case for the follower just to take the
remote segment as it is and start fetching from offset 120.

5016. Just to echo what Kowshik was saying. It seems that
RLMM.onPartitionLeadershipChanges() is only called on the replicas for a
partition, not on the replicas for the __remote_log_segment_metadata
partition. It's not clear how the leader of __remote_log_segment_metadata
obtains the metadata for remote segments for deletion.

5100. KIP-516 has been accepted and is being implemented now. Could you
update the KIP based on topicID?

5101. RLMM: It would be useful to clarify how the following two APIs are
used. According to the wiki, the former is used for topic deletion and the
latter is used for retention. It seems that retention should use the former
since remote segments without a matching epoch in the leader (potentially
due to unclean leader election) also need to be garbage collected. The
latter seems to be used for the new leader to determine the last tiered
segment.
    default Iterator<RemoteLogSegmentMetadata>
listRemoteLogSegments(TopicPartition topicPartition)
    Iterator<RemoteLogSegmentMetadata> listRemoteLogSegments(TopicPartition
topicPartition, long leaderEpoch);

5102. RSM:
5102.1 For methods like fetchLogSegmentData(), it seems that they can
use RemoteLogSegmentId instead of RemoteLogSegmentMetadata.
5102.2 In fetchLogSegmentData(), should we use long instead of Long?
5102.3 Why only some of the methods have default implementation and others
don't?
5102.4. Could we define RemoteLogSegmentMetadataUpdate
and DeletePartitionUpdate?
5102.5 LogSegmentData: It seems that it's easier to pass
in leaderEpochIndex as a ByteBuffer or byte array than a file since it will
be generated in memory.
5102.6 RemoteLogSegmentMetadata: It seems that it needs both baseOffset and
startOffset. For example, deleteRecords() could move the startOffset to the
middle of a segment. If we copy the full segment to remote storage, the
baseOffset and the startOffset will be different.
5102.7 Could we define all the public methods for RemoteLogSegmentMetadata
and LogSegmentData?
5102.8 Could we document whether endOffset in RemoteLogSegmentMetadata is
inclusive/exclusive?

5103. configs:
5103.1 Could we define the default value of non-required configs (e.g the
size of new thread pools)?
5103.2 It seems that local.log.retention.ms should default to retention.ms,
instead of remote.log.retention.minutes. Similarly, it seems
that local.log.retention.bytes should default to segment.bytes.
5103.3 remote.log.manager.thread.pool.size: The description says "used in
scheduling tasks to copy segments, fetch remote log indexes and clean up
remote log segments". However, there is a separate
config remote.log.reader.threads for fetching remote data. It's weird to
fetch remote index and log in different thread pools since both are used
for serving fetch requests.
5103.4 remote.log.manager.task.interval.ms: Is that the amount of time to
back off when there is no work to do? If so, perhaps it can be renamed as
backoff.ms.
5103.5 Are rlm_process_interval_ms and rlm_retry_interval_ms configs? If
so, they need to be listed in this section.

5104. "RLM maintains a bounded cache(possibly LRU) of the index files of
remote log segments to avoid multiple index fetches from the remote
storage." Is the RLM in memory or on disk? If on disk, where is it stored?
Do we need a configuration to bound the size?

5105. The KIP uses local-log-start-offset and Earliest Local Offset in
different places. It would be useful to standardize the terminology.

5106. The section on "In BuildingRemoteLogAux state". It listed two options
without saying which option is chosen.

5107. Follower to leader transition: It has step 2, but not step 1.

5108. If a consumer fetches from the remote data and the remote storage is
not available, what error code is used in the fetch response?

5109. "ListOffsets: For timestamps >= 0, it returns the first message
offset whose timestamp is >= to the given timestamp in the request. That
means it checks in remote log time indexes first, after which local log
time indexes are checked." Could you document which method in RLMM is used
for this?

5110. Stopreplica: "it sets all the remote log segment metadata of that
partition with a delete marker and publishes them to RLMM." This seems
outdated given the new topic deletion logic.

5111. "RLM follower fetches the earliest offset for the earliest leader
epoch by calling RLMM.earliestLogOffset(TopicPartition topicPartition, int
leaderEpoch) and updates that as the log start offset." Do we need that
since replication propagates logStartOffset already?

5112. Is the default maxWaitMs of 500ms enough for fetching from remote
storage?

5113. "Committed offsets can be stored in a local file to avoid reading the
messages again when a broker is restarted." Could you describe the format
and the location of the file? Also, could the same message be processed by
RLMM again after broker restart? If so, how do we handle that?

5114. Message format
5114.1 There are two records named RemoteLogSegmentMetadataRecord with
apiKey 0 and 1.
5114.2 RemoteLogSegmentMetadataRecord: Could we document whether endOffset
is inclusive/exclusive?
5114.3 RemoteLogSegmentMetadataRecord: Could you explain LeaderEpoch a bit
more? Is that the epoch of the leader when it copies the segment to remote
storage? Also, how will this field be used?
5114.4 EventTimestamp: Could you explain this a bit more? Each record in
Kafka already has a timestamp field. Could we just use that?
5114.5 SegmentSizeInBytes: Could this just be int32?

5115. RemoteLogCleaner(RLC): This could be confused with the log cleaner
for compaction. Perhaps it can be renamed to sth like
RemotePartitionRemover.

5116. "RLC receives the delete_partition_marked and processes it if it is
not yet processed earlier." How does it know whether
delete_partition_marked has been processed earlier?

5117. Should we add a new MessageFormatter to read the tier metadata topic?

5118. "Maximum remote log reader thread pool task queue size. If the task
queue is full, broker will stop reading remote log segments." What do we
return to the fetch request in this case?

5119. It would be useful to list all things not supported in the first
version in a Future work or Limitations section. For example, compacted
topic, JBOD, changing remote.log.storage.enable from true to false, etc.

Thanks,

Jun

On Tue, Oct 27, 2020 at 5:57 PM Kowshik Prakasam <kp...@confluent.io>
wrote:

> Hi Satish,
>
> Thanks for the updates to the KIP. Here are my first batch of
> comments/suggestions on the latest version of the KIP.
>
> 5012. In the RemoteStorageManager interface, there is an API defined for
> each file type. For example, fetchOffsetIndex, fetchTimestampIndex etc. To
> avoid the duplication, I'd suggest we can instead have a FileType enum and
> a common get API based on the FileType.
>
> 5013. There are some references to the Google doc in the KIP. I wasn't sure
> if the Google doc is expected to be in sync with the contents of the wiki.
> Going forward, it seems easier if just the KIP is maintained as the source
> of truth. In this regard, could you please move all the references to the
> Google doc, maybe to a separate References section at the bottom of the
> KIP?
>
> 5014. There are some TODO sections in the KIP. Would these be filled up in
> future iterations?
>
> 5015. Under "Topic deletion lifecycle", I'm trying to understand why do we
> need delete_partition_marked as well as the delete_partition_started
> messages. I couldn't spot a drawback if supposing we simplified the design
> such that the controller would only write delete_partition_started message,
> and RemoteLogCleaner (RLC) instance picks it up for processing. What am I
> missing?
>
> 5016. Under "Topic deletion lifecycle", step (4) is mentioned as "RLC gets
> all the remote log segments for the partition and each of these remote log
> segments is deleted with the next steps.". Since the RLC instance runs on
> each tier topic partition leader, how does the RLC then get the list of
> remote log segments to be deleted? It will be useful to add that detail to
> the KIP.
>
> 5017. Under "Public Interfaces -> Configs", there is a line mentioning "We
> will support flipping remote.log.storage.enable in next versions." It will
> be useful to mention this in the "Future Work" section of the KIP too.
>
> 5018. The KIP introduces a number of configuration parameters. It will be
> useful to mention in the KIP if the user should assume these as static
> configuration in the server.properties file, or dynamic configuration which
> can be modified without restarting the broker.
>
> 5019.  Maybe this is planned as a future update to the KIP, but I thought
> I'd mention it here. Could you please add details to the KIP on why RocksDB
> was chosen as the default cache implementation of RLMM, and how it is going
> to be used? Were alternatives compared/considered? For example, it would be
> useful to explain/evaluate the following: 1) debuggability of the RocksDB
> JNI interface, 2) performance, 3) portability across platforms and 4)
> interface parity of RocksDB’s JNI api with it's underlying C/C++ api.
>
> 5020. Following up on (5019), for the RocksDB cache, it will be useful to
> explain the relationship/mapping between the following in the KIP: 1) # of
> tiered partitions, 2) # of partitions of metadata topic
> __remote_log_metadata and 3) # of RocksDB instances. i.e. is the plan to
> have a RocksDB instance per tiered partition, or per metadata topic
> partition, or just 1 for per broker?
>
> 5021. I was looking at the implementation prototype (PR link:
> https://github.com/apache/kafka/pull/7561). It seems that a boolean
> attribute is being introduced into the Log layer to check if remote log
> capability is enabled. While the boolean footprint is small at the moment,
> this can easily grow in the future and become harder to
> test/maintain, considering that the Log layer is already pretty complex. We
> should start thinking about how to manage such changes to the Log layer
> (for the purpose of improved testability, better separation of concerns and
> readability). One proposal I have is to take a step back and define a
> higher level Log interface. Then, the Broker code can be changed to use
> this interface. It can be changed such that only a handle to the interface
> is exposed to other components (such as LogCleaner, ReplicaManager etc.)
> and not the underlying Log object. This approach keeps the user of the Log
> layer agnostic of the whereabouts of the data. Underneath the interface,
> the implementing classes can completely separate local log capabilities
> from the remote log. For example, the Log class can be simplified to only
> manage logic surrounding local log segments and metadata. Additionally, a
> wrapper class can be provided (implementing the higher level Log interface)
> which will contain any/all logic surrounding tiered data. The wrapper
> class will wrap around an instance of the Log class delegating the local
> log logic to it. Finally, a handle to the wrapper class can be exposed to
> the other components wherever they need a handle to the higher level Log
> interface.
>
>
> Cheers,
> Kowshik
>
> On Mon, Oct 26, 2020 at 9:52 PM Satish Duggana <sa...@gmail.com>
> wrote:
>
> > Hi,
> > KIP is updated with 1) topic deletion lifecycle and its related items
> > 2) Protocol changes(mainly related to ListOffsets) and other minor
> > changes.
> > Please go through them and let us know your comments.
> >
> > Thanks,
> > Satish.
> >
> > On Mon, Sep 28, 2020 at 9:10 PM Satish Duggana <satish.duggana@gmail.com
> >
> > wrote:
> > >
> > > Hi Dhruvil,
> > > Thanks for looking into the KIP and sending your comments. Sorry for
> > > the late reply, missed it in the mail thread.
> > >
> > > 1. Could you describe how retention would work with this KIP and which
> > > threads are responsible for driving this work? I believe there are 3
> > kinds
> > > of retention processes we are looking at:
> > >   (a) Regular retention for data in tiered storage as per configured `
> > > retention.ms` / `retention.bytes`.
> > >   (b) Local retention for data in local storage as per configured `
> > > local.log.retention.ms` / `local.log.retention.bytes`
> > >   (c) Possibly regular retention for data in local storage, if the
> > tiering
> > > task is lagging or for data that is below the log start offset.
> > >
> > > Local log retention is done by the existing log cleanup tasks. These
> > > are not done for segments that are not yet copied to remote storage.
> > > Remote log cleanup is done by the leader partition’s RLMTask.
> > >
> > > 2. When does a segment become eligible to be tiered? Is it as soon as
> the
> > > segment is rolled and the end offset is less than the last stable
> offset
> > as
> > > mentioned in the KIP? I wonder if we need to consider other parameters
> > too,
> > > like the highwatermark so that we are guaranteed that what we are
> tiering
> > > has been committed to the log and accepted by the ISR.
> > >
> > > AFAIK, last stable offset is always <= highwatermark. This will make
> > > sure we are always tiering the message segments which have been
> > > accepted by ISR and transactionally completed.
> > >
> > >
> > > 3. The section on "Follower Fetch Scenarios" is useful but is a bit
> > > difficult to parse at the moment. It would be useful to summarize the
> > > changes we need in the ReplicaFetcher.
> > >
> > > It may become difficult for users to read/follow if we add code changes
> > here.
> > >
> > > 4. Related to the above, it's a bit unclear how we are planning on
> > > restoring the producer state for a new replica. Could you expand on
> that?
> > >
> > > It is mentioned in the KIP BuildingRemoteLogAuxState is introduced to
> > > build the state like leader epoch sequence and producer snapshots
> > > before it starts fetching the data from the leader. We will make it
> > > clear in the KIP.
> > >
> > >
> > > 5. Similarly, it would be worth summarizing the behavior on unclean
> > leader
> > > election. There are several scenarios to consider here: data loss from
> > > local log, data loss from remote log, data loss from metadata topic,
> etc.
> > > It's worth describing these in detail.
> > >
> > > We mentioned the cases about unclean leader election in the follower
> > > fetch scenarios.
> > > If there are errors while fetching data from remote store or metadata
> > > store, it will work the same way as it works with local log. It
> > > returns the error back to the caller. Please let us know if I am
> > > missing your point here.
> > >
> > >
> > > 7. For a READ_COMMITTED FetchRequest, how do we retrieve and return the
> > > aborted transaction metadata?
> > >
> > > When a fetch for a remote log is accessed, we will fetch aborted
> > > transactions along with the segment if it is not found in the local
> > > index cache. This includes the case of transaction index not existing
> > > in the remote log segment. That means, the cache entry can be empty or
> > > have a list of aborted transactions.
> > >
> > >
> > > 8. The `LogSegmentData` class assumes that we have a log segment,
> offset
> > > index, time index, transaction index, producer snapshot and leader
> epoch
> > > index. How do we deal with cases where we do not have one or more of
> > these?
> > > For example, we may not have a transaction index or producer snapshot
> > for a
> > > particular segment. The former is optional, and the latter is only kept
> > for
> > > up to the 3 latest segments.
> > >
> > > This is a good point,  we discussed this in the last meeting.
> > > Transaction index is optional and we will copy them only if it exists.
> > > We want to keep all the producer snapshots at each log segment rolling
> > > and they can be removed if the log copying is successful and it still
> > > maintains the existing latest 3 segments, We only delete the producer
> > > snapshots which have been copied to remote log segments on leader.
> > > Follower will keep the log segments beyond the segments which have not
> > > been copied to remote storage. We will update the KIP with these
> > > details.
> > >
> > > Thanks,
> > > Satish.
> > >
> > > On Thu, Sep 17, 2020 at 1:47 AM Dhruvil Shah <dh...@confluent.io>
> > wrote:
> > > >
> > > > Hi Satish, Harsha,
> > > >
> > > > Thanks for the KIP. Few questions below:
> > > >
> > > > 1. Could you describe how retention would work with this KIP and
> which
> > > > threads are responsible for driving this work? I believe there are 3
> > kinds
> > > > of retention processes we are looking at:
> > > >   (a) Regular retention for data in tiered storage as per configured
> `
> > > > retention.ms` / `retention.bytes`.
> > > >   (b) Local retention for data in local storage as per configured `
> > > > local.log.retention.ms` / `local.log.retention.bytes`
> > > >   (c) Possibly regular retention for data in local storage, if the
> > tiering
> > > > task is lagging or for data that is below the log start offset.
> > > >
> > > > 2. When does a segment become eligible to be tiered? Is it as soon as
> > the
> > > > segment is rolled and the end offset is less than the last stable
> > offset as
> > > > mentioned in the KIP? I wonder if we need to consider other
> parameters
> > too,
> > > > like the highwatermark so that we are guaranteed that what we are
> > tiering
> > > > has been committed to the log and accepted by the ISR.
> > > >
> > > > 3. The section on "Follower Fetch Scenarios" is useful but is a bit
> > > > difficult to parse at the moment. It would be useful to summarize the
> > > > changes we need in the ReplicaFetcher.
> > > >
> > > > 4. Related to the above, it's a bit unclear how we are planning on
> > > > restoring the producer state for a new replica. Could you expand on
> > that?
> > > >
> > > > 5. Similarly, it would be worth summarizing the behavior on unclean
> > leader
> > > > election. There are several scenarios to consider here: data loss
> from
> > > > local log, data loss from remote log, data loss from metadata topic,
> > etc.
> > > > It's worth describing these in detail.
> > > >
> > > > 6. It would be useful to add details about how we plan on using
> > RocksDB in
> > > > the default implementation of `RemoteLogMetadataManager`.
> > > >
> > > > 7. For a READ_COMMITTED FetchRequest, how do we retrieve and return
> the
> > > > aborted transaction metadata?
> > > >
> > > > 8. The `LogSegmentData` class assumes that we have a log segment,
> > offset
> > > > index, time index, transaction index, producer snapshot and leader
> > epoch
> > > > index. How do we deal with cases where we do not have one or more of
> > these?
> > > > For example, we may not have a transaction index or producer snapshot
> > for a
> > > > particular segment. The former is optional, and the latter is only
> > kept for
> > > > up to the 3 latest segments.
> > > >
> > > > Thanks,
> > > > Dhruvil
> > > >
> > > > On Mon, Sep 7, 2020 at 6:54 PM Harsha Ch <ha...@gmail.com>
> wrote:
> > > >
> > > > > Hi All,
> > > > >
> > > > > We are all working through the last meeting feedback. I'll cancel
> the
> > > > > tomorrow 's meeting and we can meanwhile continue our discussion in
> > mailing
> > > > > list. We can start the regular meeting from next week onwards.
> > > > >
> > > > > Thanks,
> > > > >
> > > > > Harsha
> > > > >
> > > > > On Fri, Sep 04, 2020 at 8:41 AM, Satish Duggana <
> > satish.duggana@gmail.com
> > > > > > wrote:
> > > > >
> > > > > >
> > > > > >
> > > > > >
> > > > > > Hi Jun,
> > > > > > Thanks for your thorough review and comments. Please find the
> > inline
> > > > > > replies below.
> > > > > >
> > > > > >
> > > > > >
> > > > > > 600. The topic deletion logic needs more details.
> > > > > > 600.1 The KIP mentions "The controller considers the topic
> > partition is
> > > > > > deleted only when it determines that there are no log segments
> for
> > that
> > > > > > topic partition by using RLMM". How is this done?
> > > > > >
> > > > > >
> > > > > >
> > > > > > It uses RLMM#listSegments() returns all the segments for the
> given
> > topic
> > > > > > partition.
> > > > > >
> > > > > >
> > > > > >
> > > > > > 600.2 "If the delete option is enabled then the leader will stop
> > RLM task
> > > > > > and stop processing and it sets all the remote log segment
> > metadata of
> > > > > > that partition with a delete marker and publishes them to RLMM."
> We
> > > > > > discussed this earlier. When a topic is being deleted, there may
> > not be a
> > > > > > leader for the deleted partition.
> > > > > >
> > > > > >
> > > > > >
> > > > > > This is a good point. As suggested in the meeting, we will add a
> > separate
> > > > > > section for topic/partition deletion lifecycle and this scenario
> > will be
> > > > > > addressed.
> > > > > >
> > > > > >
> > > > > >
> > > > > > 601. Unclean leader election
> > > > > > 601.1 Scenario 1: new empty follower
> > > > > > After step 1, the follower restores up to offset 3. So why does
> it
> > have
> > > > > > LE-2 <https://issues.apache.org/jira/browse/LE-2> at offset 5?
> > > > > >
> > > > > >
> > > > > >
> > > > > > Nice catch. It was showing the leader epoch fetched from the
> remote
> > > > > > storage. It should be shown with the truncated till offset 3.
> > Updated the
> > > > > > KIP.
> > > > > >
> > > > > >
> > > > > >
> > > > > > 601.2 senario 5: After Step 3, leader A has inconsistent data
> > between its
> > > > > > local and the tiered data. For example. offset 3 has msg 3 LE-0
> > <https://issues.apache.org/jira/browse/LE-0> locally,
> > > > > > but msg 5 LE-1 <https://issues.apache.org/jira/browse/LE-1> in
> > the remote store. While it's ok for the unclean leader
> > > > > > to lose data, it should still return consistent data, whether
> it's
> > from
> > > > > > the local or the remote store.
> > > > > >
> > > > > >
> > > > > >
> > > > > > There is no inconsistency here as LE-0
> > <https://issues.apache.org/jira/browse/LE-0> offsets are [0, 4] and LE-2
> > <https://issues.apache.org/jira/browse/LE-2>:
> > > > > > [5, ]. It will always get the right records for the given offset
> > and
> > > > > > leader epoch. In case of remote, RSM is invoked to get the remote
> > log
> > > > > > segment that contains the given offset with the leader epoch.
> > > > > >
> > > > > >
> > > > > >
> > > > > > 601.4 It seems that retention is based on
> > > > > > listRemoteLogSegments(TopicPartition topicPartition, long
> > leaderEpoch).
> > > > > > When there is an unclean leader election, it's possible for the
> new
> > > > > leader
> > > > > > to not to include certain epochs in its epoch cache. How are
> remote
> > > > > > segments associated with those epochs being cleaned?
> > > > > >
> > > > > >
> > > > > >
> > > > > > That is a good point. This leader will also cleanup the epochs
> > earlier to
> > > > > > its start leader epoch and delete those segments. It gets the
> > earliest
> > > > > > epoch for a partition and starts deleting segments from that
> leader
> > > > > epoch.
> > > > > > We need one more API in RLMM to get the earliest leader epoch.
> > > > > >
> > > > > >
> > > > > >
> > > > > > 601.5 The KIP discusses the handling of unclean leader elections
> > for user
> > > > > > topics. What about unclean leader elections on
> > > > > > __remote_log_segment_metadata?
> > > > > > This is the same as other system topics like consumer_offsets,
> > > > > > __transaction_state topics. As discussed in the meeting, we will
> > add the
> > > > > > behavior of __remote_log_segment_metadata topic’s unclean leader
> > > > > > truncation.
> > > > > >
> > > > > >
> > > > > >
> > > > > > 602. It would be useful to clarify the limitations in the initial
> > > > > release.
> > > > > > The KIP mentions not supporting compacted topics. What about JBOD
> > and
> > > > > > changing the configuration of a topic from delete to compact
> after
> > > > > remote.
> > > > > > log. storage. enable ( http://remote.log.storage.enable/ ) is
> > enabled?
> > > > > >
> > > > > >
> > > > > >
> > > > > > This was updated in the KIP earlier.
> > > > > >
> > > > > >
> > > > > >
> > > > > > 603. RLM leader tasks:
> > > > > > 603.1"It checks for rolled over LogSegments (which have the last
> > message
> > > > > > offset less than last stable offset of that topic partition) and
> > copies
> > > > > > them along with their offset/time/transaction indexes and leader
> > epoch
> > > > > > cache to the remote tier." It needs to copy the producer snapshot
> > too.
> > > > > >
> > > > > >
> > > > > >
> > > > > > Right. It copies producer snapshots too as mentioned in
> > LogSegmentData.
> > > > > >
> > > > > >
> > > > > >
> > > > > > 603.2 "Local logs are not cleaned up till those segments are
> copied
> > > > > > successfully to remote even though their retention time/size is
> > reached"
> > > > > > This seems weird. If the tiering stops because the remote store
> is
> > not
> > > > > > available, we don't want the local data to grow forever.
> > > > > >
> > > > > >
> > > > > >
> > > > > > It was clarified in the discussion that the comment was more
> about
> > the
> > > > > > local storage goes beyond the log.retention. The above statement
> > is about
> > > > > > local.log.retention but not for the complete log.retention. When
> it
> > > > > > reaches the log.retention then it will delete the local logs even
> > though
> > > > > > those are not copied to remote storage.
> > > > > >
> > > > > >
> > > > > >
> > > > > > 604. "RLM maintains a bounded cache(possibly LRU) of the index
> > files of
> > > > > > remote log segments to avoid multiple index fetches from the
> remote
> > > > > > storage. These indexes can be used in the same way as local
> segment
> > > > > > indexes are used." Could you provide more details on this? Are
> the
> > > > > indexes
> > > > > > cached in memory or on disk? If on disk, where are they stored?
> > Are the
> > > > > > cached indexes bound by a certain size?
> > > > > >
> > > > > >
> > > > > >
> > > > > > These are cached on disk and stored in log.dir with a name
> > > > > > “__remote_log_index_cache”. They are bound by the total size.
> This
> > will
> > > > > be
> > > > > > exposed as a user configuration,
> > > > > >
> > > > > >
> > > > > >
> > > > > > 605. BuildingRemoteLogAux
> > > > > > 605.1 In this section, two options are listed. Which one is
> chosen?
> > > > > > Option-2, updated the KIP.
> > > > > >
> > > > > >
> > > > > >
> > > > > > 605.2 In option 2, it says "Build the local leader epoch cache by
> > cutting
> > > > > > the leader epoch sequence received from remote storage to [LSO,
> > ELO].
> > > > > (LSO
> > > > > >
> > > > > > = log start offset)." We need to do the same thing for the
> producer
> > > > > > snapshot. However, it's hard to cut the producer snapshot to an
> > earlier
> > > > > > offset. Another option is to simply take the lastOffset from the
> > remote
> > > > > > segment and use that as the starting fetch offset in the
> follower.
> > This
> > > > > > avoids the need for cutting.
> > > > > >
> > > > > >
> > > > > >
> > > > > > Right, this was mentioned in the “transactional support” section
> > about
> > > > > > adding these details.
> > > > > >
> > > > > >
> > > > > >
> > > > > > 606. ListOffsets: Since we need a version bump, could you
> document
> > it
> > > > > > under a protocol change section?
> > > > > >
> > > > > >
> > > > > >
> > > > > > Sure, we will update the KIP.
> > > > > >
> > > > > >
> > > > > >
> > > > > > 607. "LogStartOffset of a topic can point to either of local
> > segment or
> > > > > > remote segment but it is initialised and maintained in the Log
> > class like
> > > > > > now. This is already maintained in `Log` class while loading the
> > logs and
> > > > > > it can also be fetched from RemoteLogMetadataManager." What will
> > happen
> > > > > to
> > > > > > the existing logic (e.g. log recovery) that currently depends on
> > > > > > logStartOffset but assumes it's local?
> > > > > >
> > > > > >
> > > > > >
> > > > > > They use a field called localLogStartOffset which is the local
> log
> > start
> > > > > > offset..
> > > > > >
> > > > > >
> > > > > >
> > > > > > 608. Handle expired remote segment: How does it pick up new
> > > > > logStartOffset
> > > > > > from deleteRecords?
> > > > > >
> > > > > >
> > > > > >
> > > > > > Good point. This was not addressed in the KIP. Will update the
> KIP
> > on how
> > > > > > the RLM task handles this scenario.
> > > > > >
> > > > > >
> > > > > >
> > > > > > 609. RLMM message format:
> > > > > > 609.1 It includes both MaxTimestamp and EventTimestamp. Where
> does
> > it get
> > > > > > both since the message in the log only contains one timestamp?
> > > > > >
> > > > > >
> > > > > >
> > > > > > `EventTimeStamp` is the timestamp at which that segment metadata
> > event is
> > > > > > generated. This is more for audits.
> > > > > >
> > > > > >
> > > > > >
> > > > > > 609.2 If we change just the state (e.g. to DELETE_STARTED), it
> > seems it's
> > > > > > wasteful to have to include all other fields not changed.
> > > > > >
> > > > > >
> > > > > >
> > > > > > This is a good point. We thought about incremental updates. But
> we
> > want
> > > > > to
> > > > > > make sure all the events are in the expected order and take
> action
> > based
> > > > > > on the latest event. Will think through the approaches in detail
> > and
> > > > > > update here.
> > > > > >
> > > > > >
> > > > > >
> > > > > > 609.3 Could you document which process makes the following
> > transitions
> > > > > > DELETE_MARKED, DELETE_STARTED, DELETE_FINISHED?
> > > > > >
> > > > > >
> > > > > >
> > > > > > Okay, will document more details.
> > > > > >
> > > > > >
> > > > > >
> > > > > > 610. remote.log.reader.max.pending.tasks: "Maximum remote log
> > reader
> > > > > > thread pool task queue size. If the task queue is full, broker
> > will stop
> > > > > > reading remote log segments." What does the broker do if the
> queue
> > is
> > > > > > full?
> > > > > >
> > > > > >
> > > > > >
> > > > > > It returns an error for this topic partition.
> > > > > >
> > > > > >
> > > > > >
> > > > > > 611. What do we return if the request offset/epoch doesn't exist
> > in the
> > > > > > following API?
> > > > > > RemoteLogSegmentMetadata remoteLogSegmentMetadata(TopicPartition
> > > > > > topicPartition, long offset, int epochForOffset)
> > > > > >
> > > > > >
> > > > > >
> > > > > > This returns null. But we prefer to update the return type as
> > Optional
> > > > > and
> > > > > > return Empty if that does not exist.
> > > > > >
> > > > > >
> > > > > >
> > > > > > Thanks,
> > > > > > Satish.
> > > > > >
> > > > > >
> > > > > >
> > > > > > On Tue, Sep 1, 2020 at 9:45 AM Jun Rao < jun@ confluent. io (
> > > > > > jun@confluent.io ) > wrote:
> > > > > >
> > > > > >
> > > > > >>
> > > > > >>
> > > > > >> Hi, Satish,
> > > > > >>
> > > > > >>
> > > > > >>
> > > > > >> Thanks for the updated KIP. Made another pass. A few more
> comments
> > > > > below.
> > > > > >>
> > > > > >>
> > > > > >>
> > > > > >> 600. The topic deletion logic needs more details.
> > > > > >> 600.1 The KIP mentions "The controller considers the topic
> > partition is
> > > > > >> deleted only when it determines that there are no log segments
> > for that
> > > > > >> topic partition by using RLMM". How is this done? 600.2 "If the
> > delete
> > > > > >> option is enabled then the leader will stop RLM task and stop
> > processing
> > > > > >> and it sets all the remote log segment metadata of that
> partition
> > with a
> > > > > >> delete marker and publishes them to RLMM." We discussed this
> > earlier.
> > > > > When
> > > > > >> a topic is being deleted, there may not be a leader for the
> > deleted
> > > > > >> partition.
> > > > > >>
> > > > > >>
> > > > > >>
> > > > > >> 601. Unclean leader election
> > > > > >> 601.1 Scenario 1: new empty follower
> > > > > >> After step 1, the follower restores up to offset 3. So why does
> > it have
> > > > > >> LE-2 <https://issues.apache.org/jira/browse/LE-2> at offset 5?
> > > > > >> 601.2 senario 5: After Step 3, leader A has inconsistent data
> > between
> > > > > its
> > > > > >> local and the tiered data. For example. offset 3 has msg 3 LE-0
> > <https://issues.apache.org/jira/browse/LE-0> locally,
> > > > > >> but msg 5 LE-1 <https://issues.apache.org/jira/browse/LE-1> in
> > the remote store. While it's ok for the unclean leader
> > > > > >> to lose data, it should still return consistent data, whether
> > it's from
> > > > > >> the local or the remote store.
> > > > > >> 601.3 The follower picks up log start offset using the following
> > api.
> > > > > >> Suppose that we have 3 remote segments (LE, SegmentStartOffset)
> > as (2,
> > > > > >> 10),
> > > > > >> (3, 20) and (7, 15) due to an unclean leader election. Using the
> > > > > following
> > > > > >> api will cause logStartOffset to go backward from 20 to 15. How
> > do we
> > > > > >> prevent that?
> > > > > >> earliestLogOffset(TopicPartition topicPartition, int
> leaderEpoch)
> > 601.4
> > > > > It
> > > > > >> seems that retention is based on
> > > > > >> listRemoteLogSegments(TopicPartition topicPartition, long
> > leaderEpoch).
> > > > > >> When there is an unclean leader election, it's possible for the
> > new
> > > > > leader
> > > > > >> to not to include certain epochs in its epoch cache. How are
> > remote
> > > > > >> segments associated with those epochs being cleaned? 601.5 The
> KIP
> > > > > >> discusses the handling of unclean leader elections for user
> > topics. What
> > > > > >> about unclean leader elections on
> > > > > >> __remote_log_segment_metadata?
> > > > > >>
> > > > > >>
> > > > > >>
> > > > > >> 602. It would be useful to clarify the limitations in the
> initial
> > > > > release.
> > > > > >> The KIP mentions not supporting compacted topics. What about
> JBOD
> > and
> > > > > >> changing the configuration of a topic from delete to compact
> after
> > > > > remote.
> > > > > >> log. storage. enable ( http://remote.log.storage.enable/ ) is
> > enabled?
> > > > > >>
> > > > > >>
> > > > > >>
> > > > > >> 603. RLM leader tasks:
> > > > > >> 603.1"It checks for rolled over LogSegments (which have the last
> > message
> > > > > >> offset less than last stable offset of that topic partition) and
> > copies
> > > > > >> them along with their offset/time/transaction indexes and leader
> > epoch
> > > > > >> cache to the remote tier." It needs to copy the producer
> snapshot
> > too.
> > > > > >> 603.2 "Local logs are not cleaned up till those segments are
> > copied
> > > > > >> successfully to remote even though their retention time/size is
> > reached"
> > > > > >> This seems weird. If the tiering stops because the remote store
> > is not
> > > > > >> available, we don't want the local data to grow forever.
> > > > > >>
> > > > > >>
> > > > > >>
> > > > > >> 604. "RLM maintains a bounded cache(possibly LRU) of the index
> > files of
> > > > > >> remote log segments to avoid multiple index fetches from the
> > remote
> > > > > >> storage. These indexes can be used in the same way as local
> > segment
> > > > > >> indexes are used." Could you provide more details on this? Are
> the
> > > > > indexes
> > > > > >> cached in memory or on disk? If on disk, where are they stored?
> > Are the
> > > > > >> cached indexes bound by a certain size?
> > > > > >>
> > > > > >>
> > > > > >>
> > > > > >> 605. BuildingRemoteLogAux
> > > > > >> 605.1 In this section, two options are listed. Which one is
> > chosen?
> > > > > 605.2
> > > > > >> In option 2, it says "Build the local leader epoch cache by
> > cutting the
> > > > > >> leader epoch sequence received from remote storage to [LSO,
> ELO].
> > (LSO
> > > > > >> = log start offset)." We need to do the same thing for the
> > producer
> > > > > >> snapshot. However, it's hard to cut the producer snapshot to an
> > earlier
> > > > > >> offset. Another option is to simply take the lastOffset from the
> > remote
> > > > > >> segment and use that as the starting fetch offset in the
> > follower. This
> > > > > >> avoids the need for cutting.
> > > > > >>
> > > > > >>
> > > > > >>
> > > > > >> 606. ListOffsets: Since we need a version bump, could you
> > document it
> > > > > >> under a protocol change section?
> > > > > >>
> > > > > >>
> > > > > >>
> > > > > >> 607. "LogStartOffset of a topic can point to either of local
> > segment or
> > > > > >> remote segment but it is initialised and maintained in the Log
> > class
> > > > > like
> > > > > >> now. This is already maintained in `Log` class while loading the
> > logs
> > > > > and
> > > > > >> it can also be fetched from RemoteLogMetadataManager." What will
> > happen
> > > > > to
> > > > > >> the existing logic (e.g. log recovery) that currently depends on
> > > > > >> logStartOffset but assumes it's local?
> > > > > >>
> > > > > >>
> > > > > >>
> > > > > >> 608. Handle expired remote segment: How does it pick up new
> > > > > logStartOffset
> > > > > >> from deleteRecords?
> > > > > >>
> > > > > >>
> > > > > >>
> > > > > >> 609. RLMM message format:
> > > > > >> 609.1 It includes both MaxTimestamp and EventTimestamp. Where
> > does it
> > > > > get
> > > > > >> both since the message in the log only contains one timestamp?
> > 609.2 If
> > > > > we
> > > > > >> change just the state (e.g. to DELETE_STARTED), it seems it's
> > wasteful
> > > > > to
> > > > > >> have to include all other fields not changed. 609.3 Could you
> > document
> > > > > >> which process makes the following transitions DELETE_MARKED,
> > > > > >> DELETE_STARTED, DELETE_FINISHED?
> > > > > >>
> > > > > >>
> > > > > >>
> > > > > >> 610. remote.log.reader.max.pending.tasks: "Maximum remote log
> > reader
> > > > > >> thread pool task queue size. If the task queue is full, broker
> > will stop
> > > > > >> reading remote log segments." What does the broker do if the
> > queue is
> > > > > >> full?
> > > > > >>
> > > > > >>
> > > > > >>
> > > > > >> 611. What do we return if the request offset/epoch doesn't exist
> > in the
> > > > > >> following API?
> > > > > >> RemoteLogSegmentMetadata remoteLogSegmentMetadata(TopicPartition
> > > > > >> topicPartition, long offset, int epochForOffset)
> > > > > >>
> > > > > >>
> > > > > >>
> > > > > >> Jun
> > > > > >>
> > > > > >>
> > > > > >>
> > > > > >> On Mon, Aug 31, 2020 at 11:19 AM Satish Duggana < satish.
> duggana@
> > > > > gmail. com
> > > > > >> ( satish.duggana@gmail.com ) > wrote:
> > > > > >>
> > > > > >>
> > > > > >>>
> > > > > >>>
> > > > > >>> KIP is updated with
> > > > > >>> - Remote log segment metadata topic message format/schema.
> > > > > >>> - Added remote log segment metadata state transitions and
> > explained how
> > > > > >>> the deletion of segments is handled, including the case of
> > partition
> > > > > >>> deletions.
> > > > > >>> - Added a few more limitations in the "Non goals" section.
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > > >>> Thanks,
> > > > > >>> Satish.
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > > >>> On Thu, Aug 27, 2020 at 12:42 AM Harsha Ch < harsha. ch@
> gmail.
> > com (
> > > > > >>> harsha.ch@gmail.com ) > wrote:
> > > > > >>>
> > > > > >>>
> > > > > >>>>
> > > > > >>>>
> > > > > >>>> Updated the KIP with Meeting Notes section
> > > > > >>>>
> > > > > >>>>
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > > >>> https:/ / cwiki. apache. org/ confluence/ display/ KAFKA/
> > > > > KIP-405 <https://issues.apache.org/jira/browse/KIP-405>
> > %3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> > > > > >>> (
> > > > > >>>
> > > > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-405%3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> > > > > >>> )
> > > > > >>>
> > > > > >>>
> > > > > >>>>
> > > > > >>>>
> > > > > >>>> On Tue, Aug 25, 2020 at 1:03 PM Jun Rao < jun@ confluent. io
> (
> > > > > >>>> jun@confluent.io ) > wrote:
> > > > > >>>>
> > > > > >>>>
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>> Hi, Harsha,
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>> Thanks for the summary. Could you add the summary and the
> > recording
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>
> > > > > >>>>
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > > >>> link to
> > > > > >>>
> > > > > >>>
> > > > > >>>>
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>> the last section of
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>
> > > > > >>>>
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > > >>> https:/ / cwiki. apache. org/ confluence/ display/ KAFKA/
> > > > > Kafka+Improvement+Proposals
> > > > > >>> (
> > > > > >>>
> > > > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/Kafka+Improvement+Proposals
> > > > > >>> )
> > > > > >>>
> > > > > >>>
> > > > > >>>>
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>> ?
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>> Jun
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>> On Tue, Aug 25, 2020 at 11:12 AM Harsha Chintalapani < kafka@
> > > > > harsha. io (
> > > > > >>>>> kafka@harsha.io ) > wrote:
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>> Thanks everyone for attending the meeting today.
> > > > > >>>>>> Here is the recording
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>
> > > > > >>>>
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > > >>> https:/ / drive. google. com/ file/ d/
> > > > > 14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/ view?usp=sharing
> > > > > >>> (
> > > > > >>>
> > > > >
> >
> https://drive.google.com/file/d/14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/view?usp=sharing
> > > > > >>> )
> > > > > >>>
> > > > > >>>
> > > > > >>>>
> > > > > >>>>>
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>> Notes:
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>> 1. KIP is updated with follower fetch protocol and ready to
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>
> > > > > >>>>
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > > >>> reviewed
> > > > > >>>
> > > > > >>>
> > > > > >>>>
> > > > > >>>>>
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>> 2. Satish to capture schema of internal metadata topic in
> the
> > KIP
> > > > > >>>>>> 3. We will update the KIP with details of different cases
> > > > > >>>>>> 4. Test plan will be captured in a doc and will add to the
> KIP
> > > > > >>>>>> 5. Add a section "Limitations" to capture the capabilities
> > that
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>
> > > > > >>>>
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > > >>> will
> > > > > >>>
> > > > > >>>
> > > > > >>>>
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>> be
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>> introduced with this KIP and what will not be covered in
> this
> > KIP.
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>> Please add to it I missed anything. Will produce a formal
> > meeting
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>
> > > > > >>>>
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > > >>> notes
> > > > > >>>
> > > > > >>>
> > > > > >>>>
> > > > > >>>>>
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>> from next meeting onwards.
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>> Thanks,
> > > > > >>>>>> Harsha
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>> On Mon, Aug 24, 2020 at 9:42 PM, Ying Zheng < yingz@ uber.
> > com.
> > > > > invalid (
> > > > > >>>>>> yingz@uber.com.invalid ) > wrote:
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> We did some basic feature tests at Uber. The test cases and
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>
> > > > > >>>>
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > > >>> results are
> > > > > >>>
> > > > > >>>
> > > > > >>>>
> > > > > >>>>>
> > > > > >>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> shared in this google doc:
> > > > > >>>>>>> https:/ / docs. google. com/ spreadsheets/ d/ (
> > > > > >>>>>>> https://docs.google.com/spreadsheets/d/ )
> > > > > >>>>>>>
> 1XhNJqjzwXvMCcAOhEH0sSXU6RTvyoSf93DHF-YMfGLk/edit?usp=sharing
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> The performance test results were already shared in the KIP
> > last
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>
> > > > > >>>>
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > > >>> month.
> > > > > >>>
> > > > > >>>
> > > > > >>>>
> > > > > >>>>>
> > > > > >>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> On Mon, Aug 24, 2020 at 11:10 AM Harsha Ch < harsha. ch@
> > gmail.
> > > > > com (
> > > > > >>>>>>> harsha.ch@gmail.com ) >
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>> wrote:
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> "Understand commitments towards driving design &
> > implementation of
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>
> > > > > >>>>
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > > >>> the
> > > > > >>>
> > > > > >>>
> > > > > >>>>
> > > > > >>>>>
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>> KIP
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> further and how it aligns with participant interests in
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>
> > > > > >>>>
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > > >>> contributing to
> > > > > >>>
> > > > > >>>
> > > > > >>>>
> > > > > >>>>>
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>> the
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> efforts (ex: in the context of Uber’s Q3/Q4 roadmap)." What
> > is that
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>> about?
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> On Mon, Aug 24, 2020 at 11:05 AM Kowshik Prakasam <
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>> kprakasam@ confluent. io ( kprakasam@confluent.io ) >
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> wrote:
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Hi Harsha,
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> The following google doc contains a proposal for temporary
> > agenda
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>
> > > > > >>>>
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > > >>> for
> > > > > >>>
> > > > > >>>
> > > > > >>>>
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>> the
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> KIP-405 <https://issues.apache.org/jira/browse/KIP-405> <
> > https:/ / issues. apache. org/ jira/ browse/ KIP-405
> > <https://issues.apache.org/jira/browse/KIP-405> (
> > > > > >>>>>>> https://issues.apache.org/jira/browse/KIP-405 ) > sync
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>
> > > > > >>>>
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > > >>> meeting
> > > > > >>>
> > > > > >>>
> > > > > >>>>
> > > > > >>>>>
> > > > > >>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> tomorrow:
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> https:/ / docs. google. com/ document/ d/ (
> > > > > >>>>>>> https://docs.google.com/document/d/ )
> > > > > >>>>>>> 1pqo8X5LU8TpwfC_iqSuVPezhfCfhGkbGN2TqiPA3LBU/edit
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> .
> > > > > >>>>>>> Please could you add it to the Google calendar invite?
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Thank you.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Cheers,
> > > > > >>>>>>> Kowshik
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> On Thu, Aug 20, 2020 at 10:58 AM Harsha Ch < harsha. ch@
> > gmail.
> > > > > com (
> > > > > >>>>>>> harsha.ch@gmail.com ) >
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>> wrote:
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Hi All,
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Scheduled a meeting for Tuesday 9am - 10am. I can record
> and
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>
> > > > > >>>>
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > > >>> upload for
> > > > > >>>
> > > > > >>>
> > > > > >>>>
> > > > > >>>>>
> > > > > >>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> community to be able to follow the discussion.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Jun, please add the required folks on confluent side.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Thanks,
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Harsha
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> On Thu, Aug 20, 2020 at 12:33 AM, Alexandre Dupriez <
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>> alexandre.dupriez@
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> gmail. com ( http://gmail.com/ ) > wrote:
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Hi Jun,
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Many thanks for your initiative.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> If you like, I am happy to attend at the time you
> suggested.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Many thanks,
> > > > > >>>>>>> Alexandre
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Le mer. 19 août 2020 à 22:00, Harsha Ch < harsha. ch@
> > gmail. com (
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>> harsha.
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> ch@ gmail. com ( ch@gmail.com ) ) > a écrit :
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Hi Jun,
> > > > > >>>>>>> Thanks. This will help a lot. Tuesday will work for us.
> > > > > >>>>>>> -Harsha
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> On Wed, Aug 19, 2020 at 1:24 PM Jun Rao < jun@ confluent.
> > io (
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>
> > > > > >>>>
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > > >>> jun@
> > > > > >>>
> > > > > >>>
> > > > > >>>>
> > > > > >>>>>
> > > > > >>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> confluent. io ( http://confluent.io/ ) ) > wrote:
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Hi, Satish, Ying, Harsha,
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Do you think it would be useful to have a regular virtual
> > meeting
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>
> > > > > >>>>
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > > >>> to
> > > > > >>>
> > > > > >>>
> > > > > >>>>
> > > > > >>>>>
> > > > > >>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> discuss this KIP? The goal of the meeting will be sharing
> > > > > >>>>>>> design/development progress and discussing any open issues
> to
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> accelerate
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> this KIP. If so, will every Tuesday (from next week)
> 9am-10am
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> PT
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> work for you? I can help set up a Zoom meeting, invite
> > everyone who
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> might
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> be interested, have it recorded and shared, etc.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Thanks,
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Jun
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> On Tue, Aug 18, 2020 at 11:01 AM Satish Duggana <
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> satish. duggana@ gmail. com ( satish. duggana@ gmail. com
> (
> > > > > >>>>>>> satish.duggana@gmail.com ) ) >
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> wrote:
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Hi Kowshik,
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Thanks for looking into the KIP and sending your comments.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> 5001. Under the section "Follower fetch protocol in
> detail",
> > the
> > > > > >>>>>>> next-local-offset is the offset upto which the segments are
> > copied
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> to
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> remote storage. Instead, would last-tiered-offset be a
> > better name
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> than
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> next-local-offset? last-tiered-offset seems to naturally
> > align well
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> with
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> the definition provided in the KIP.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Both next-local-offset and local-log-start-offset were
> > introduced
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> to
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> talk
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> about offsets related to local log. We are fine with
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> last-tiered-offset
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> too as you suggested.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> 5002. After leadership is established for a partition, the
> > leader
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> would
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> begin uploading a segment to remote storage. If successful,
> > the
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> leader
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> would write the updated RemoteLogSegmentMetadata to the
> > metadata
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> topic
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> (via
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> RLMM.putRemoteLogSegmentData). However, for defensive
> > reasons, it
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> seems
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> useful that before the first time the segment is uploaded
> by
> > the
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> leader
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> for
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> a partition, the leader should ensure to catch up to all
> the
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> metadata
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> events written so far in the metadata topic for that
> > partition (ex:
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> by
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> previous leader). To achieve this, the leader could start a
> > lease
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> (using
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> an
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> establish_leader metadata event) before commencing tiering,
> > and
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> wait
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> until
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> the event is read back. For example, this seems useful to
> > avoid
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> cases
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> where
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> zombie leaders can be active for the same partition. This
> > can also
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> prove
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> useful to help avoid making decisions on which segments to
> be
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> uploaded
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> for
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> a partition, until the current leader has caught up to a
> > complete
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> view
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> of
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> all segments uploaded for the partition so far (otherwise
> > this may
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> cause
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> same segment being uploaded twice -- once by the previous
> > leader
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> and
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> then
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> by the new leader).
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> We allow copying segments to remote storage which may have
> > common
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> offsets.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Please go through the KIP to understand the follower fetch
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> protocol(1) and
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> follower to leader transition(2).
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> https:/ / cwiki. apache. org/ confluence/ display/ KAFKA/
> > KIP-405 <https://issues.apache.org/jira/browse/KIP-405>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> < https:/ / issues. apache. org/ jira/ browse/ KIP-405
> > <https://issues.apache.org/jira/browse/KIP-405> (
> > > > > >>>>>>> https://issues.apache.org/jira/browse/KIP-405 ) >
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>
> > > > > >>>>
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > %3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-FollowerReplication
> > > > > >>>
> > > > > >>>
> > > > > >>>>
> > > > > >>>>>
> > > > > >>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> (
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> https:/ / cwiki. apache. org/ confluence/ display/ KAFKA/ (
> > > > > >>>>>>> https://cwiki.apache.org/confluence/display/KAFKA/ )
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>
> > > > > >>>>
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > > KIP-405 <https://issues.apache.org/jira/browse/KIP-405>
> > %3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-FollowerReplication
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > > >>>>
> > > > > >>>>>
> > > > > >>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> )
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> https:/ / cwiki. apache. org/ confluence/ display/ KAFKA/
> > KIP-405 <https://issues.apache.org/jira/browse/KIP-405>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> < https:/ / issues. apache. org/ jira/ browse/ KIP-405
> > <https://issues.apache.org/jira/browse/KIP-405> (
> > > > > >>>>>>> https://issues.apache.org/jira/browse/KIP-405 ) >
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>
> > > > > >>>>
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > >
> >
> %3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-Followertoleadertransition
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > > >>>>
> > > > > >>>>>
> > > > > >>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> (
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> https:/ / cwiki. apache. org/ confluence/ display/ KAFKA/ (
> > > > > >>>>>>> https://cwiki.apache.org/confluence/display/KAFKA/ )
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>
> > > > > >>>>
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > > KIP-405 <https://issues.apache.org/jira/browse/KIP-405>
> >
> %3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-Followertoleadertransition
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > > >>>>
> > > > > >>>>>
> > > > > >>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> )
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> 5003. There is a natural interleaving between uploading a
> > segment
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> to
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> remote
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> store, and, writing a metadata event for the same (via
> > > > > >>>>>>> RLMM.putRemoteLogSegmentData). There can be cases where a
> > remote
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> segment
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> is
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> uploaded, then the leader fails and a corresponding
> metadata
> > event
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> never
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> gets written. In such cases, the orphaned remote segment
> has
> > to be
> > > > > >>>>>>> eventually deleted (since there is no confirmation of the
> > upload).
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> To
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> handle this, we could use 2 separate metadata events viz.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> copy_initiated
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> and copy_completed, so that copy_initiated events that
> don't
> > have a
> > > > > >>>>>>> corresponding copy_completed event can be treated as
> garbage
> > and
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> deleted
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> from the remote object store by the broker.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> We are already updating RMM with RemoteLogSegmentMetadata
> > pre and
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> post
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> copying of log segments. We had a flag in
> > RemoteLogSegmentMetadata
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> whether
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> it is copied or not. But we are making changes in
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> RemoteLogSegmentMetadata
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> to introduce a state field in RemoteLogSegmentMetadata
> which
> > will
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> have the
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> respective started and finished states. This includes for
> > other
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> operations
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> like delete too.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> 5004. In the default implementation of RLMM (using the
> > internal
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> topic
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> __remote_log_metadata), a separate topic called
> > > > > >>>>>>> __remote_segments_to_be_deleted is going to be used just to
> > track
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> failures
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> in removing remote log segments. A separate topic
> > (effectively
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> another
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> metadata stream) introduces some maintenance overhead and
> > design
> > > > > >>>>>>> complexity. It seems to me that the same can be achieved
> > just by
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> using
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> just
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> the __remote_log_metadata topic with the following steps:
> 1)
> > the
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> leader
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> writes a delete_initiated metadata event, 2) the leader
> > deletes the
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> segment
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> and 3) the leader writes a delete_completed metadata event.
> > Tiered
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> segments
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> that have delete_initiated message and not delete_completed
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> message,
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> can
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> be
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> considered to be a failure and retried.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Jun suggested in earlier mail to keep this simple . We
> > decided not
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> to have
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> this topic as mentioned in our earlier replies, updated the
> > KIP.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> As I
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> mentioned in an earlier comment, we are adding state
> entries
> > for
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> delete
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> operations too.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> 5005. When a Kafka cluster is provisioned for the first
> time
> > with
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> KIP-405 <https://issues.apache.org/jira/browse/KIP-405> <
> > https:/ / issues. apache. org/ jira/ browse/ KIP-405
> > <https://issues.apache.org/jira/browse/KIP-405> (
> > > > > >>>>>>> https://issues.apache.org/jira/browse/KIP-405 ) >
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> tiered storage enabled, could you explain in the KIP about
> > how the
> > > > > >>>>>>> bootstrap for __remote_log_metadata topic will be performed
> > in the
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> the
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> default RLMM implementation?
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> __remote_log_segment_metadata topic is created by default
> > with the
> > > > > >>>>>>> respective topic like partitions/replication-factor etc.
> Can
> > you be
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> more
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> specific on what you are looking for?
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> 5008. The system-wide configuration ' remote. log. storage.
> > enable
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> (
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> http:/ / remote. log. storage. enable/ (
> > > > > http://remote.log.storage.enable/
> > > > > >>>>>>> ) ) ' is used
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> to
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> enable tiered storage. Can this be made a topic-level
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> configuration,
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> so
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> that the user can enable/disable tiered storage at a topic
> > level
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> rather
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> than a system-wide default for an entire Kafka cluster?
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Yes, we mentioned in an earlier mail thread that it will be
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> supported at
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> topic level too, updated the KIP.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> 5009. Whenever a topic with tiered storage enabled is
> > deleted, the
> > > > > >>>>>>> underlying actions require the topic data to be deleted in
> > local
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> store
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> as
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> well as remote store, and eventually the topic metadata
> > needs to be
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> deleted
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> too. What is the role of the controller in deleting a topic
> > and
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> it's
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> contents, while the topic has tiered storage enabled?
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> When a topic partition is deleted, there will be an event
> > for that
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> in RLMM
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> for its deletion and the controller considers that topic is
> > deleted
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> only
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> when all the remote log segments are also deleted.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> 5010. RLMM APIs are currently synchronous, for example
> > > > > >>>>>>> RLMM.putRemoteLogSegmentData waits until the put operation
> is
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> completed
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> in
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> the remote metadata store. It may also block until the
> > leader has
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> caught
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> up
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> to the metadata (not sure). Could we make these apis
> > asynchronous
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> (ex:
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> based on java.util.concurrent.Future) to provide room for
> > tapping
> > > > > >>>>>>> performance improvements such as non-blocking i/o? 5011.
> The
> > same
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> question
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> as 5009 on sync vs async api for RSM. Have we considered
> the
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> pros/cons of
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> making the RSM apis asynchronous?
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Async methods are used to do other tasks while the result
> is
> > not
> > > > > >>>>>>> available. In this case, we need to have the result before
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> proceeding to
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> take next actions. These APIs are evolving and these can be
> > updated
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> as and
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> when needed instead of having them as asynchronous now.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Thanks,
> > > > > >>>>>>> Satish.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> On Fri, Aug 14, 2020 at 4:30 AM Kowshik Prakasam <
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> kprakasam@ confluent. io ( kprakasam@ confluent. io (
> > > > > >>>>>>> kprakasam@confluent.io ) )
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> wrote:
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Hi Harsha/Satish,
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Thanks for the great KIP. Below are the first set of
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> questions/suggestions
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> I had after making a pass on the KIP.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> 5001. Under the section "Follower fetch protocol in
> detail",
> > the
> > > > > >>>>>>> next-local-offset is the offset upto which the segments are
> > copied
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> to
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> remote storage. Instead, would last-tiered-offset be a
> > better name
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> than
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> next-local-offset? last-tiered-offset seems to naturally
> > align
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> well
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> with
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> the definition provided in the KIP.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> 5002. After leadership is established for a partition, the
> > leader
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> would
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> begin uploading a segment to remote storage. If successful,
> > the
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> leader
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> would write the updated RemoteLogSegmentMetadata to the
> > metadata
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> topic
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> (via
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> RLMM.putRemoteLogSegmentData). However, for defensive
> > reasons, it
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> seems
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> useful that before the first time the segment is uploaded
> by
> > the
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> leader
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> for
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> a partition, the leader should ensure to catch up to all
> the
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> metadata
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> events written so far in the metadata topic for that
> > partition
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> (ex:
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> by
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> previous leader). To achieve this, the leader could start a
> > lease
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> (using
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> an
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> establish_leader metadata event) before commencing tiering,
> > and
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> wait
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> until
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> the event is read back. For example, this seems useful to
> > avoid
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> cases
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> where
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> zombie leaders can be active for the same partition. This
> > can also
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> prove
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> useful to help avoid making decisions on which segments to
> be
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> uploaded
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> for
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> a partition, until the current leader has caught up to a
> > complete
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> view
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> of
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> all segments uploaded for the partition so far (otherwise
> > this may
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> cause
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> same segment being uploaded twice -- once by the previous
> > leader
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> and
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> then
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> by the new leader).
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> 5003. There is a natural interleaving between uploading a
> > segment
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> to
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> remote
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> store, and, writing a metadata event for the same (via
> > > > > >>>>>>> RLMM.putRemoteLogSegmentData). There can be cases where a
> > remote
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> segment
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> is
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> uploaded, then the leader fails and a corresponding
> metadata
> > event
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> never
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> gets written. In such cases, the orphaned remote segment
> has
> > to be
> > > > > >>>>>>> eventually deleted (since there is no confirmation of the
> > upload).
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> To
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> handle this, we could use 2 separate metadata events viz.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> copy_initiated
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> and copy_completed, so that copy_initiated events that
> don't
> > have
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> a
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> corresponding copy_completed event can be treated as
> garbage
> > and
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> deleted
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> from the remote object store by the broker.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> 5004. In the default implementation of RLMM (using the
> > internal
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> topic
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> __remote_log_metadata), a separate topic called
> > > > > >>>>>>> __remote_segments_to_be_deleted is going to be used just to
> > track
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> failures
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> in removing remote log segments. A separate topic
> > (effectively
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> another
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> metadata stream) introduces some maintenance overhead and
> > design
> > > > > >>>>>>> complexity. It seems to me that the same can be achieved
> > just by
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> using
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> just
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> the __remote_log_metadata topic with the following steps:
> 1)
> > the
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> leader
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> writes a delete_initiated metadata event, 2) the leader
> > deletes
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> the
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> segment
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> and 3) the leader writes a delete_completed metadata event.
> > Tiered
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> segments
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> that have delete_initiated message and not delete_completed
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> message,
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> can
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> be
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> considered to be a failure and retried.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> 5005. When a Kafka cluster is provisioned for the first
> time
> > with
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> KIP-405 <https://issues.apache.org/jira/browse/KIP-405> <
> > https:/ / issues. apache. org/ jira/ browse/ KIP-405
> > <https://issues.apache.org/jira/browse/KIP-405> (
> > > > > >>>>>>> https://issues.apache.org/jira/browse/KIP-405 ) >
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> tiered storage enabled, could you explain in the KIP about
> > how the
> > > > > >>>>>>> bootstrap for __remote_log_metadata topic will be performed
> > in the
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> the
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> default RLMM implementation?
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> 5006. I currently do not see details on the KIP on why
> > RocksDB was
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> chosen
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> as the default cache implementation, and how it is going to
> > be
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> used.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Were
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> alternatives compared/considered? For example, it would be
> > useful
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> to
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> explain/evaulate the following: 1) debuggability of the
> > RocksDB
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> JNI
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> interface, 2) performance, 3) portability across platforms
> > and 4)
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> interface
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> parity of RocksDB’s JNI api with it's underlying C/C++ api.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> 5007. For the RocksDB cache (the default implementation of
> > RLMM),
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> what
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> is
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> the relationship/mapping between the following: 1) # of
> > tiered
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> partitions,
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> 2) # of partitions of metadata topic __remote_log_metadata
> > and 3)
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> #
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> of
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> RocksDB instances? i.e. is the plan to have a RocksDB
> > instance per
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> tiered
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> partition, or per metadata topic partition, or just 1 for
> per
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> broker?
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> 5008. The system-wide configuration ' remote. log. storage.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> enable (
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> http:/ / remote. log. storage. enable/ (
> > > > > http://remote.log.storage.enable/
> > > > > >>>>>>> ) ) ' is
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> used
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> to
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> enable tiered storage. Can this be made a topic-level
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> configuration,
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> so
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> that the user can enable/disable tiered storage at a topic
> > level
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> rather
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> than a system-wide default for an entire Kafka cluster?
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> 5009. Whenever a topic with tiered storage enabled is
> > deleted, the
> > > > > >>>>>>> underlying actions require the topic data to be deleted in
> > local
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> store
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> as
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> well as remote store, and eventually the topic metadata
> > needs to
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> be
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> deleted
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> too. What is the role of the controller in deleting a topic
> > and
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> it's
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> contents, while the topic has tiered storage enabled?
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> 5010. RLMM APIs are currently synchronous, for example
> > > > > >>>>>>> RLMM.putRemoteLogSegmentData waits until the put operation
> is
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> completed
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> in
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> the remote metadata store. It may also block until the
> > leader has
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> caught
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> up
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> to the metadata (not sure). Could we make these apis
> > asynchronous
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> (ex:
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> based on java.util.concurrent.Future) to provide room for
> > tapping
> > > > > >>>>>>> performance improvements such as non-blocking i/o?
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> 5011. The same question as 5009 on sync vs async api for
> > RSM. Have
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> we
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> considered the pros/cons of making the RSM apis
> asynchronous?
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Cheers,
> > > > > >>>>>>> Kowshik
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> On Thu, Aug 6, 2020 at 11:02 AM Satish Duggana <
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> satish. duggana@ gmail. com ( satish. duggana@ gmail. com
> (
> > > > > >>>>>>> satish.duggana@gmail.com ) )
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> wrote:
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Hi Jun,
> > > > > >>>>>>> Thanks for your comments.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> At the high level, that approach sounds reasonable to
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> me. It would be useful to document how RLMM handles
> > overlapping
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> archived
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> offset ranges and how those overlapping segments are
> deleted
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> through
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> retention.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Sure, we will document that in the KIP.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> How is the remaining part of the KIP coming along? To me,
> the
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> two
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> biggest
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> missing items are (1) more detailed documentation on how
> all
> > the
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> new
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> APIs
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> are being used and (2) metadata format and usage in the
> > internal
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> topic
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> __remote_log_metadata.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> We are working on updating APIs based on the recent
> > discussions
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> and get
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> the perf numbers by plugging in rocksdb as a cache store
> for
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> RLMM.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> We will update the KIP with the updated APIs and with the
> > above
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> requested
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> details in a few days and let you know.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Thanks,
> > > > > >>>>>>> Satish.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> On Wed, Aug 5, 2020 at 12:49 AM Jun Rao < jun@ confluent.
> > io (
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>
> > > > > >>>>
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > > >>> jun@
> > > > > >>>
> > > > > >>>
> > > > > >>>>
> > > > > >>>>>
> > > > > >>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> confluent. io ( http://confluent.io/ ) ) > wrote:
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Hi, Ying, Satish,
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Thanks for the reply. At the high level, that approach
> sounds
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> reasonable
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> to
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> me. It would be useful to document how RLMM handles
> > overlapping
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> archived
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> offset ranges and how those overlapping segments are
> deleted
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> through
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> retention.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> How is the remaining part of the KIP coming along? To me,
> the
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> two
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> biggest
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> missing items are (1) more detailed documentation on how
> all
> > the
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> new
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> APIs
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> are being used and (2) metadata format and usage in the
> > internal
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> topic
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> __remote_log_metadata.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Thanks,
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Jun
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> On Tue, Aug 4, 2020 at 8:32 AM Satish Duggana <
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> satish. duggana@ gmail. com ( satish. duggana@ gmail. com
> (
> > > > > >>>>>>> satish.duggana@gmail.com ) ) >
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> wrote:
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Hi Jun,
> > > > > >>>>>>> Thanks for your comment,
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> 1001. Using the new leader as the source of truth may be
> fine
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> too.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> What's
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> not clear to me is when a follower takes over as the new
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> leader,
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> from
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> which
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> offset does it start archiving to the block storage. I
> assume
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> that
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> the
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> new
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> leader starts from the latest archived ooffset by the
> > previous
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> leader,
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> but
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> it seems that's not the case. It would be useful to
> document
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> this
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> in
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> the
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Wiki.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> When a follower becomes a leader it needs to findout the
> > offset
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> from
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> which the segments to be copied to remote storage. This is
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> found
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> by
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> traversing from the the latest leader epoch from leader
> epoch
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> history
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> and find the highest offset of a segment with that epoch
> > copied
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> into
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> remote storage by using respective RLMM APIs. If it can not
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> find
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> an
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> entry then it checks for the previous leader epoch till it
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> finds
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> an
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> entry, If there are no entries till the earliest leader
> epoch
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> in
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> leader epoch cache then it starts copying the segments from
> > the
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> earliest
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> epoch entry’s offset.
> > > > > >>>>>>> Added an example in the KIP here[1]. We will update RLMM
> APIs
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> in
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> the
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> KIP.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> https:/ / cwiki. apache. org/ confluence/ display/ KAFKA/
> > KIP-405 <https://issues.apache.org/jira/browse/KIP-405>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> < https:/ / issues. apache. org/ jira/ browse/ KIP-405
> > <https://issues.apache.org/jira/browse/KIP-405> (
> > > > > >>>>>>> https://issues.apache.org/jira/browse/KIP-405 ) >
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>
> > > > > >>>>
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > >
> >
> %3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-Followertoleadertransition
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > > >>>>
> > > > > >>>>>
> > > > > >>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> (
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> https:/ / cwiki. apache. org/ confluence/ display/ KAFKA/ (
> > > > > >>>>>>> https://cwiki.apache.org/confluence/display/KAFKA/ )
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>
> > > > > >>>>
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > > KIP-405 <https://issues.apache.org/jira/browse/KIP-405>
> >
> %3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-Followertoleadertransition
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > > >>>>
> > > > > >>>>>
> > > > > >>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> )
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Satish.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> On Tue, Aug 4, 2020 at 9:00 PM Satish Duggana <
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> satish. duggana@ gmail. com ( satish. duggana@ gmail. com
> (
> > > > > >>>>>>> satish.duggana@gmail.com ) ) >
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> wrote:
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Hi Ying,
> > > > > >>>>>>> Thanks for your comment.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> 1001. Using the new leader as the source of truth may be
> fine
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> too.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> What's
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> not clear to me is when a follower takes over as the new
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> leader,
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> from
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> which
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> offset does it start archiving to the block storage. I
> assume
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> that
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> the
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> new
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> leader starts from the latest archived ooffset by the
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> previous
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> leader,
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> but
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> it seems that's not the case. It would be useful to
> document
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> this in
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> the
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Wiki.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> When a follower becomes a leader it needs to findout the
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> offset
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> from
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> which the segments to be copied to remote storage. This is
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> found
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> by
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> traversing from the the latest leader epoch from leader
> epoch
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> history
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> and find the highest offset of a segment with that epoch
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> copied
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> into
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> remote storage by using respective RLMM APIs. If it can not
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> find
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> an
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> entry then it checks for the previous leader epoch till it
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> finds
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> an
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> entry, If there are no entries till the earliest leader
> epoch
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> in
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> leader epoch cache then it starts copying the segments from
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> the
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> earliest epoch entry’s offset.
> > > > > >>>>>>> Added an example in the KIP here[1]. We will update RLMM
> APIs
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> in
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> the
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> KIP.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> https:/ / cwiki. apache. org/ confluence/ display/ KAFKA/
> > KIP-405 <https://issues.apache.org/jira/browse/KIP-405>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> < https:/ / issues. apache. org/ jira/ browse/ KIP-405
> > <https://issues.apache.org/jira/browse/KIP-405> (
> > > > > >>>>>>> https://issues.apache.org/jira/browse/KIP-405 ) >
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>
> > > > > >>>>
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > >
> >
> %3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-Followertoleadertransition
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > > >>>>
> > > > > >>>>>
> > > > > >>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> (
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> https:/ / cwiki. apache. org/ confluence/ display/ KAFKA/ (
> > > > > >>>>>>> https://cwiki.apache.org/confluence/display/KAFKA/ )
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>
> > > > > >>>>
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > > KIP-405 <https://issues.apache.org/jira/browse/KIP-405>
> >
> %3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-Followertoleadertransition
> > > > > >>>
> > > > > >>>
> > > > > >>>
> > > > > >>>>
> > > > > >>>>>
> > > > > >>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> )
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Satish.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> On Tue, Aug 4, 2020 at 10:28 AM Ying Zheng
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> < yingz@ uber. com. invalid ( yingz@ uber. com. invalid (
> > > > > >>>>>>> yingz@uber.com.invalid ) ) >
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> wrote:
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Hi Jun,
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Thank you for the comment! The current KIP is not very
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> clear
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> about
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> this
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> part.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> 1001. The new leader will start archiving from the earliest
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> local
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> segment
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> that is not fully
> > > > > >>>>>>> covered by the "valid" remote data. "valid" means the
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> (offset,
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> leader
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> epoch) pair is valid
> > > > > >>>>>>> based on the leader-epoch history.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> There are some edge cases where the same offset range (with
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> the
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> same
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> leader
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> epoch) can
> > > > > >>>>>>> be copied to the remote storage more than once. But this
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> kind
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> of
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> duplication shouldn't be a
> > > > > >>>>>>> problem.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Staish is going to explain the details in the KIP with
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> examples.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> On Fri, Jul 31, 2020 at 2:55 PM Jun Rao < jun@ confluent.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> io (
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> jun@ confluent. io ( jun@confluent.io ) ) >
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> wrote:
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Hi, Ying,
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Thanks for the reply.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> 1001. Using the new leader as the source of truth may be
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> fine
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> too.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> What's
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> not clear to me is when a follower takes over as the new
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> leader,
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> from which
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> offset does it start archiving to the block storage. I
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> assume
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> that
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> the new
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> leader starts from the latest archived ooffset by the
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> previous
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> leader, but
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> it seems that's not the case. It would be useful to
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> document
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> this in
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> the
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> wiki.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> Jun
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> On Tue, Jul 28, 2020 at 12:11 PM Ying Zheng
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> < yingz@ uber. com. invalid ( yingz@ uber. com. invalid (
> > > > > >>>>>>> yingz@uber.com.invalid ) ) >
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> wrote:
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> 1001.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> We did consider this approach. The concerns are
> > > > > >>>>>>> 1) This makes unclean-leader-election rely on remote
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> storage.
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> In
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> case
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> the
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>> remote storage
> > > > > >>>>>>> is unavailable, Kafka will not be able to finish the
> > > > > >>>>>>>
> > > > > >>>>>>>
> > > > > >>>>>>
> > > > > >>>>>>
> > > > > >>>>>
> > > > > >>>>>
> > > > > >>>>
> > > > > >>>>
> > > > > >>>
> > > > > >>>
> > > > > >>
> > > > > >>
> > > > > >
> > > > > >
> > > > > >
> >
>

Re: [DISCUSS] KIP-405: Kafka Tiered Storage

[Kowshik Prakasam <kp...@confluent.io>]

Hi Harsha/Satish,

Hope you are doing well. Would you be able to please update the meeting
notes section for the most recent 2 meetings (from 10/13 and 11/10)? It
will be useful to share the context with the community.
https://cwiki.apache.org/confluence/display/KAFKA/KIP-405%3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes


Cheers,
Kowshik


On Tue, Nov 10, 2020 at 11:39 PM Kowshik Prakasam <kp...@confluent.io>
wrote:

> Hi Harsha,
>
> The goal we discussed is to aim for preview in AK 3.0. In order to get us
> there, it will be useful to think about the order in which the code changes
> will be implemented, reviewed and merged. Since you are driving the
> development, do you want to layout the order of things? For example, do you
> eventually want to break up the PR into multiple smaller ones? If so, you
> could list the milestones there. Another perspective is that this can be
> helpful to budget time suitably and to understand the progress.
> Let us know how we can help.
>
>
> Cheers,
> Kowshik
>
> On Tue, Nov 10, 2020 at 3:26 PM Harsha Chintalapani <ka...@harsha.io>
> wrote:
>
>> Thanks Kowshik for the link. Seems reasonable,  as we discussed on the
>> call, code and completion of this KIP will be taken up by us.
>> Regarding Milestone 2, what you think it needs to be clarified there?
>> I believe what we are promising in the KIP along with unit tests, systems
>> tests will be delivered and we can call that as preview.   We will be
>> running this in our production and continue to provide the data and
>> metrics
>> to push this feature to GA.
>>
>>
>>
>> On Tue, Nov 10, 2020 at 10:07 AM, Kowshik Prakasam <
>> kprakasam@confluent.io>
>> wrote:
>>
>> > Hi Harsha/Satish,
>> >
>> > Thanks for the discussion today. Here is a link to the KIP-405
>> <https://issues.apache.org/jira/browse/KIP-405> development
>> > milestones google doc we discussed in the meeting today: https://docs.
>> > google.com/document/d/1B5_jaZvWWb2DUpgbgImq0k_IPZ4DWrR8Ru7YpuJrXdc/edit
>> > . I have shared it with you. Please have a look and share your
>> > feedback/improvements. As we discussed, things are clear until
>> milestone 1.
>> > Beyond that, we can discuss it again (perhaps in next sync or later),
>> once
>> > you have thought through the implementation plan/milestones and release
>> > into preview in 3.0.
>> >
>> > Cheers,
>> > Kowshik
>> >
>> > On Tue, Nov 10, 2020 at 6:56 AM Satish Duggana <
>> satish.duggana@gmail.com>
>> > wrote:
>> >
>> > Hi Jun,
>> > Thanks for your comments. Please find the inline replies below.
>> >
>> > 605.2 "Build the local leader epoch cache by cutting the leader epoch
>> > sequence received from remote storage to [LSO, ELO]." I mentioned an
>> issue
>> > earlier. Suppose the leader's local start offset is 100. The follower
>> finds
>> > a remote segment covering offset range [80, 120). The producerState with
>> > this remote segment is up to offset 120. To trim the producerState to
>> > offset 100 requires more work since one needs to download the previous
>> > producerState up to offset 80 and then replay the messages from 80 to
>> 100.
>> > It seems that it's simpler in this case for the follower just to take
>> the
>> > remote segment as it is and start fetching from offset 120.
>> >
>> > We chose that approach to avoid any edge cases here. It may be possible
>> > that the remote log segment that is received may not have the same
>> leader
>> > epoch sequence from 100-120 as it contains on the leader(this can happen
>> > due to unclean leader). It is safe to start from what the leader returns
>> > here.Another way is to find the remote log segment
>> >
>> > 5016. Just to echo what Kowshik was saying. It seems that
>> > RLMM.onPartitionLeadershipChanges() is only called on the replicas for a
>> > partition, not on the replicas for the __remote_log_segment_metadata
>> > partition. It's not clear how the leader of
>> __remote_log_segment_metadata
>> > obtains the metadata for remote segments for deletion.
>> >
>> > RLMM will always receive the callback for the remote log metadata topic
>> > partitions hosted on the local broker and these will be subscribed. I
>> will
>> > make this clear in the KIP.
>> >
>> > 5100. KIP-516 <https://issues.apache.org/jira/browse/KIP-516> has been
>> accepted and is being implemented now. Could you
>> > update the KIP based on topicID?
>> >
>> > We mentioned KIP-516 <https://issues.apache.org/jira/browse/KIP-516>
>> and how it helps. We will update this KIP with all
>> > the changes it brings with KIP-516
>> <https://issues.apache.org/jira/browse/KIP-516>.
>> >
>> > 5101. RLMM: It would be useful to clarify how the following two APIs are
>> > used. According to the wiki, the former is used for topic deletion and
>> the
>> > latter is used for retention. It seems that retention should use the
>> former
>> > since remote segments without a matching epoch in the leader
>> (potentially
>> > due to unclean leader election) also need to be garbage collected. The
>> > latter seems to be used for the new leader to determine the last tiered
>> > segment.
>> > default Iterator<RemoteLogSegmentMetadata>
>> > listRemoteLogSegments(TopicPartition topicPartition)
>> > Iterator<RemoteLogSegmentMetadata> listRemoteLogSegments(TopicPartition
>> > topicPartition, long leaderEpoch);
>> >
>> > Right,.that is what we are currently doing. We will update the javadocs
>> > and wiki with that. Earlier, we did not want to remove the segments
>> which
>> > are not matched with leader epochs from the ladder partition as they
>> may be
>> > used later by a replica which can become a leader (unclean leader
>> election)
>> > and refer those segments. But that may leak these segments in remote
>> > storage until the topic lifetime. We decided to cleanup the segments
>> with
>> > the oldest incase of size based retention also.
>> >
>> > 5102. RSM:
>> > 5102.1 For methods like fetchLogSegmentData(), it seems that they can
>> use
>> > RemoteLogSegmentId instead of RemoteLogSegmentMetadata.
>> >
>> > It will be useful to have metadata for RSM to fetch log segment. It may
>> > create location/path using id with other metadata too.
>> >
>> > 5102.2 In fetchLogSegmentData(), should we use long instead of Long?
>> >
>> > Wanted to keep endPosition as optional to read till the end of the
>> segment
>> > and avoid sentinels.
>> >
>> > 5102.3 Why only some of the methods have default implementation and
>> others
>> > Don't?
>> >
>> > Actually, RSM will not have any default implementations. Those 3 methods
>> > were made default earlier for tests etc. Updated the wiki.
>> >
>> > 5102.4. Could we define RemoteLogSegmentMetadataUpdate and
>> > DeletePartitionUpdate?
>> >
>> > Sure, they will be added.
>> >
>> > 5102.5 LogSegmentData: It seems that it's easier to pass in
>> > leaderEpochIndex as a ByteBuffer or byte array than a file since it
>> will be
>> > generated in memory.
>> >
>> > Right, this is in plan.
>> >
>> > 5102.6 RemoteLogSegmentMetadata: It seems that it needs both baseOffset
>> > and startOffset. For example, deleteRecords() could move the
>> startOffset to
>> > the middle of a segment. If we copy the full segment to remote storage,
>> the
>> > baseOffset and the startOffset will be different.
>> >
>> > Good point. startOffset is baseOffset by default, if not set explicitly.
>> >
>> > 5102.7 Could we define all the public methods for
>> RemoteLogSegmentMetadata
>> > and LogSegmentData?
>> >
>> > Sure, updated the wiki.
>> >
>> > 5102.8 Could we document whether endOffset in RemoteLogSegmentMetadata
>> is
>> > inclusive/exclusive?
>> >
>> > It is inclusive, will update.
>> >
>> > 5103. configs:
>> > 5103.1 Could we define the default value of non-required configs (e.g
>> the
>> > size of new thread pools)?
>> >
>> > Sure, that makes sense.
>> >
>> > 5103.2 It seems that local.log.retention.ms should default to
>> retention.ms
>> > ,
>> > instead of remote.log.retention.minutes. Similarly, it seems that
>> > local.log.retention.bytes should default to segment.bytes.
>> >
>> > Right, we do not have remote.log.retention as we discussed earlier.
>> Thanks
>> > for catching the typo.
>> >
>> > 5103.3 remote.log.manager.thread.pool.size: The description says "used
>> in
>> > scheduling tasks to copy segments, fetch remote log indexes and clean up
>> > remote log segments". However, there is a separate config
>> > remote.log.reader.threads for fetching remote data. It's weird to fetch
>> > remote index and log in different thread pools since both are used for
>> > serving fetch requests.
>> >
>> > Right, remote.log.manager.thread.pool is mainly used for copy/cleanup
>> > activities. Fetch path always goes through remote.log.reader.threads.
>> >
>> > 5103.4 remote.log.manager.task.interval.ms: Is that the amount of time
>> to
>> > back off when there is no work to do? If so, perhaps it can be renamed
>> as
>> > backoff.ms.
>> >
>> > This is the delay interval for each iteration. It may be renamed to
>> > remote.log.manager.task.delay.ms
>> >
>> > 5103.5 Are rlm_process_interval_ms and rlm_retry_interval_ms configs? If
>> > so, they need to be listed in this section.
>> >
>> > remote.log.manager.task.interval.ms is the process internal, retry
>> > interval is missing in the configs, which will be updated in the KIP.
>> >
>> > 5104. "RLM maintains a bounded cache(possibly LRU) of the index files of
>> > remote log segments to avoid multiple index fetches from the remote
>> > storage." Is the RLM in memory or on disk? If on disk, where is it
>> stored?
>> > Do we need a configuration to bound the size?
>> >
>> > It is stored on disk. They are stored in a directory
>> > `remote-log-index-cache` under log dir. We plan to have a config for
>> that
>> > instead of default. We will have a configuration for that.
>> >
>> > 5105. The KIP uses local-log-start-offset and Earliest Local Offset in
>> > different places. It would be useful to standardize the terminology.
>> >
>> > Sure.
>> >
>> > 5106. The section on "In BuildingRemoteLogAux state". It listed two
>> > options without saying which option is chosen.
>> > We already mentioned in the KIP that we chose option-2.
>> >
>> > 5107. Follower to leader transition: It has step 2, but not step 1.
>> Step-1
>> > is there but it is not explicitly highlighted. It is previous table to
>> > step-2.
>> >
>> > 5108. If a consumer fetches from the remote data and the remote storage
>> is
>> > not available, what error code is used in the fetch response?
>> >
>> > Good point. We have not yet defined the error for this case. We need to
>> > define an error message and send the same in fetch response.
>> >
>> > 5109. "ListOffsets: For timestamps >= 0, it returns the first message
>> > offset whose timestamp is >= to the given timestamp in the request. That
>> > means it checks in remote log time indexes first, after which local log
>> > time indexes are checked." Could you document which method in RLMM is
>> used
>> > for this?
>> >
>> > Okay.
>> >
>> > 5110. Stopreplica: "it sets all the remote log segment metadata of that
>> > partition with a delete marker and publishes them to RLMM." This seems
>> > outdated given the new topic deletion logic.
>> >
>> > Will update with KIP-516
>> <https://issues.apache.org/jira/browse/KIP-516> related points.
>> >
>> > 5111. "RLM follower fetches the earliest offset for the earliest leader
>> > epoch by calling RLMM.earliestLogOffset(TopicPartition topicPartition,
>> int
>> > leaderEpoch) and updates that as the log start offset." Do we need that
>> > since replication propagates logStartOffset already?
>> >
>> > Good point. Right, existing replication protocol takes care of updating
>> > the followers’s log start offset received from the leader.
>> >
>> > 5112. Is the default maxWaitMs of 500ms enough for fetching from remote
>> > storage?
>> >
>> > Remote reads may fail within the current default wait time, but
>> subsequent
>> > fetches would be able to serve as that data is stored in the local
>> cache.
>> > This cache is currently implemented in RSMs. But we plan to pull this
>> into
>> > the remote log messaging layer in future.
>> >
>> > 5113. "Committed offsets can be stored in a local file to avoid reading
>> > the messages again when a broker is restarted." Could you describe the
>> > format and the location of the file? Also, could the same message be
>> > processed by RLMM again after broker restart? If so, how do we handle
>> that?
>> >
>> > Sure, we will update in the KIP.
>> >
>> > 5114. Message format
>> > 5114.1 There are two records named RemoteLogSegmentMetadataRecord with
>> > apiKey 0 and 1.
>> >
>> > Nice catch, that was a typo. Fixed in the wiki.
>> >
>> > 5114.2 RemoteLogSegmentMetadataRecord: Could we document whether
>> endOffset
>> > is inclusive/exclusive?
>> > It is inclusive, will update.
>> >
>> > 5114.3 RemoteLogSegmentMetadataRecord: Could you explain LeaderEpoch a
>> bit
>> > more? Is that the epoch of the leader when it copies the segment to
>> remote
>> > storage? Also, how will this field be used?
>> >
>> > Right, this is the leader epoch of the broker which copied this segment.
>> > This is helpful in reason about which broker copied the segment to
>> remote
>> > storage.
>> >
>> > 5114.4 EventTimestamp: Could you explain this a bit more? Each record in
>> > Kafka already has a timestamp field. Could we just use that?
>> >
>> > This is the timestamp at which the respective event occurred. Added this
>> > to RemoteLogSegmentMetadata as RLMM can be any other implementation. We
>> > thought about that but it looked cleaner to use at the message structure
>> > level instead of getting that from the consumer record and using that to
>> > build the respective event.
>> >
>> > 5114.5 SegmentSizeInBytes: Could this just be int32?
>> >
>> > Right, it looks like config allows only int value >= 14.
>> >
>> > 5115. RemoteLogCleaner(RLC): This could be confused with the log cleaner
>> > for compaction. Perhaps it can be renamed to sth like
>> > RemotePartitionRemover.
>> >
>> > I am fine with RemotePartitionRemover or RemoteLogDeletionManager(we
>> have
>> > other manager classes like RLM, RLMM).
>> >
>> > 5116. "RLC receives the delete_partition_marked and processes it if it
>> is
>> > not yet processed earlier." How does it know whether
>> > delete_partition_marked has been processed earlier?
>> >
>> > This is to handle duplicate delete_partition_marked events. RLC
>> internally
>> > maintains a state for the delete_partition events and if it already has
>> an
>> > existing event then it ignores if it is already being processed.
>> >
>> > 5117. Should we add a new MessageFormatter to read the tier metadata
>> > topic?
>> >
>> > Right, this is in plan but did not mention it in the KIP. This will be
>> > useful for debugging purposes too.
>> >
>> > 5118. "Maximum remote log reader thread pool task queue size. If the
>> task
>> > queue is full, broker will stop reading remote log segments." What do we
>> > return to the fetch request in this case?
>> >
>> > We return an error response for that partition.
>> >
>> > 5119. It would be useful to list all things not supported in the first
>> > version in a Future work or Limitations section. For example, compacted
>> > topic, JBOD, changing remote.log.storage.enable from true to false, etc.
>> >
>> > We already have a non-goals section which is filled with some of these
>> > details. Do we need another limitations section?
>> >
>> > Thanks,
>> > Satish.
>> >
>> > On Wed, Nov 4, 2020 at 11:27 PM Jun Rao <ju...@confluent.io> wrote:
>> >
>> > Hi, Satish,
>> >
>> > Thanks for the updated KIP. A few more comments below.
>> >
>> > 605.2 "Build the local leader epoch cache by cutting the leader epoch
>> > sequence received from remote storage to [LSO, ELO]." I mentioned an
>> >
>> > issue
>> >
>> > earlier. Suppose the leader's local start offset is 100. The follower
>> >
>> > finds
>> >
>> > a remote segment covering offset range [80, 120). The producerState with
>> > this remote segment is up to offset 120. To trim the producerState to
>> > offset 100 requires more work since one needs to download the previous
>> > producerState up to offset 80 and then replay the messages from 80 to
>> >
>> > 100.
>> >
>> > It seems that it's simpler in this case for the follower just to take
>> the
>> > remote segment as it is and start fetching from offset 120.
>> >
>> > 5016. Just to echo what Kowshik was saying. It seems that
>> > RLMM.onPartitionLeadershipChanges() is only called on the replicas for a
>> > partition, not on the replicas for the __remote_log_segment_metadata
>> > partition. It's not clear how the leader of
>> __remote_log_segment_metadata
>> > obtains the metadata for remote segments for deletion.
>> >
>> > 5100. KIP-516 <https://issues.apache.org/jira/browse/KIP-516> has been
>> accepted and is being implemented now. Could you
>> > update the KIP based on topicID?
>> >
>> > 5101. RLMM: It would be useful to clarify how the following two APIs are
>> > used. According to the wiki, the former is used for topic deletion and
>> >
>> > the
>> >
>> > latter is used for retention. It seems that retention should use the
>> >
>> > former
>> >
>> > since remote segments without a matching epoch in the leader
>> (potentially
>> > due to unclean leader election) also need to be garbage collected. The
>> > latter seems to be used for the new leader to determine the last tiered
>> > segment.
>> > default Iterator<RemoteLogSegmentMetadata>
>> > listRemoteLogSegments(TopicPartition topicPartition)
>> > Iterator<RemoteLogSegmentMetadata>
>> >
>> > listRemoteLogSegments(TopicPartition
>> >
>> > topicPartition, long leaderEpoch);
>> >
>> > 5102. RSM:
>> > 5102.1 For methods like fetchLogSegmentData(), it seems that they can
>> use
>> > RemoteLogSegmentId instead of RemoteLogSegmentMetadata. 5102.2 In
>> > fetchLogSegmentData(), should we use long instead of Long? 5102.3 Why
>> only
>> > some of the methods have default implementation and
>> >
>> > others
>> >
>> > don't?
>> > 5102.4. Could we define RemoteLogSegmentMetadataUpdate and
>> > DeletePartitionUpdate?
>> > 5102.5 LogSegmentData: It seems that it's easier to pass in
>> > leaderEpochIndex as a ByteBuffer or byte array than a file since it
>> >
>> > will
>> >
>> > be generated in memory.
>> > 5102.6 RemoteLogSegmentMetadata: It seems that it needs both baseOffset
>> >
>> > and
>> >
>> > startOffset. For example, deleteRecords() could move the startOffset to
>> >
>> > the
>> >
>> > middle of a segment. If we copy the full segment to remote storage, the
>> > baseOffset and the startOffset will be different.
>> > 5102.7 Could we define all the public methods for
>> >
>> > RemoteLogSegmentMetadata
>> >
>> > and LogSegmentData?
>> > 5102.8 Could we document whether endOffset in RemoteLogSegmentMetadata
>> is
>> > inclusive/exclusive?
>> >
>> > 5103. configs:
>> > 5103.1 Could we define the default value of non-required configs (e.g
>> the
>> > size of new thread pools)?
>> > 5103.2 It seems that local.log.retention.ms should default to
>> >
>> > retention.ms,
>> >
>> > instead of remote.log.retention.minutes. Similarly, it seems that
>> > local.log.retention.bytes should default to segment.bytes. 5103.3
>> > remote.log.manager.thread.pool.size: The description says "used in
>> > scheduling tasks to copy segments, fetch remote log indexes and clean up
>> > remote log segments". However, there is a separate config
>> > remote.log.reader.threads for fetching remote data. It's weird to fetch
>> > remote index and log in different thread pools since both are used for
>> > serving fetch requests.
>> > 5103.4 remote.log.manager.task.interval.ms: Is that the amount of time
>> >
>> > to
>> >
>> > back off when there is no work to do? If so, perhaps it can be renamed
>> as
>> > backoff.ms.
>> > 5103.5 Are rlm_process_interval_ms and rlm_retry_interval_ms configs? If
>> > so, they need to be listed in this section.
>> >
>> > 5104. "RLM maintains a bounded cache(possibly LRU) of the index files of
>> > remote log segments to avoid multiple index fetches from the remote
>> > storage." Is the RLM in memory or on disk? If on disk, where is it
>> >
>> > stored?
>> >
>> > Do we need a configuration to bound the size?
>> >
>> > 5105. The KIP uses local-log-start-offset and Earliest Local Offset in
>> > different places. It would be useful to standardize the terminology.
>> >
>> > 5106. The section on "In BuildingRemoteLogAux state". It listed two
>> >
>> > options
>> >
>> > without saying which option is chosen.
>> >
>> > 5107. Follower to leader transition: It has step 2, but not step 1.
>> >
>> > 5108. If a consumer fetches from the remote data and the remote storage
>> >
>> > is
>> >
>> > not available, what error code is used in the fetch response?
>> >
>> > 5109. "ListOffsets: For timestamps >= 0, it returns the first message
>> > offset whose timestamp is >= to the given timestamp in the request. That
>> > means it checks in remote log time indexes first, after which local log
>> > time indexes are checked." Could you document which method in RLMM is
>> >
>> > used
>> >
>> > for this?
>> >
>> > 5110. Stopreplica: "it sets all the remote log segment metadata of that
>> > partition with a delete marker and publishes them to RLMM." This seems
>> > outdated given the new topic deletion logic.
>> >
>> > 5111. "RLM follower fetches the earliest offset for the earliest leader
>> > epoch by calling RLMM.earliestLogOffset(TopicPartition topicPartition,
>> >
>> > int
>> >
>> > leaderEpoch) and updates that as the log start offset." Do we need that
>> > since replication propagates logStartOffset already?
>> >
>> > 5112. Is the default maxWaitMs of 500ms enough for fetching from remote
>> > storage?
>> >
>> > 5113. "Committed offsets can be stored in a local file to avoid reading
>> >
>> > the
>> >
>> > messages again when a broker is restarted." Could you describe the
>> format
>> > and the location of the file? Also, could the same message be processed
>> >
>> > by
>> >
>> > RLMM again after broker restart? If so, how do we handle that?
>> >
>> > 5114. Message format
>> > 5114.1 There are two records named RemoteLogSegmentMetadataRecord with
>> > apiKey 0 and 1.
>> > 5114.2 RemoteLogSegmentMetadataRecord: Could we document whether
>> >
>> > endOffset
>> >
>> > is inclusive/exclusive?
>> > 5114.3 RemoteLogSegmentMetadataRecord: Could you explain LeaderEpoch a
>> >
>> > bit
>> >
>> > more? Is that the epoch of the leader when it copies the segment to
>> >
>> > remote
>> >
>> > storage? Also, how will this field be used?
>> > 5114.4 EventTimestamp: Could you explain this a bit more? Each record in
>> > Kafka already has a timestamp field. Could we just use that? 5114.5
>> > SegmentSizeInBytes: Could this just be int32?
>> >
>> > 5115. RemoteLogCleaner(RLC): This could be confused with the log cleaner
>> > for compaction. Perhaps it can be renamed to sth like
>> > RemotePartitionRemover.
>> >
>> > 5116. "RLC receives the delete_partition_marked and processes it if it
>> is
>> > not yet processed earlier." How does it know whether
>> > delete_partition_marked has been processed earlier?
>> >
>> > 5117. Should we add a new MessageFormatter to read the tier metadata
>> >
>> > topic?
>> >
>> > 5118. "Maximum remote log reader thread pool task queue size. If the
>> task
>> > queue is full, broker will stop reading remote log segments." What do we
>> > return to the fetch request in this case?
>> >
>> > 5119. It would be useful to list all things not supported in the first
>> > version in a Future work or Limitations section. For example, compacted
>> > topic, JBOD, changing remote.log.storage.enable from true to false, etc.
>> >
>> > Thanks,
>> >
>> > Jun
>> >
>> > On Tue, Oct 27, 2020 at 5:57 PM Kowshik Prakasam <
>> kprakasam@confluent.io
>> >
>> > wrote:
>> >
>> > Hi Satish,
>> >
>> > Thanks for the updates to the KIP. Here are my first batch of
>> > comments/suggestions on the latest version of the KIP.
>> >
>> > 5012. In the RemoteStorageManager interface, there is an API defined
>> >
>> > for
>> >
>> > each file type. For example, fetchOffsetIndex, fetchTimestampIndex
>> >
>> > etc. To
>> >
>> > avoid the duplication, I'd suggest we can instead have a FileType enum
>> >
>> > and
>> >
>> > a common get API based on the FileType.
>> >
>> > 5013. There are some references to the Google doc in the KIP. I wasn't
>> >
>> > sure
>> >
>> > if the Google doc is expected to be in sync with the contents of the
>> >
>> > wiki.
>> >
>> > Going forward, it seems easier if just the KIP is maintained as the
>> >
>> > source
>> >
>> > of truth. In this regard, could you please move all the references to
>> >
>> > the
>> >
>> > Google doc, maybe to a separate References section at the bottom of the
>> > KIP?
>> >
>> > 5014. There are some TODO sections in the KIP. Would these be filled
>> >
>> > up in
>> >
>> > future iterations?
>> >
>> > 5015. Under "Topic deletion lifecycle", I'm trying to understand why
>> >
>> > do we
>> >
>> > need delete_partition_marked as well as the delete_partition_started
>> > messages. I couldn't spot a drawback if supposing we simplified the
>> >
>> > design
>> >
>> > such that the controller would only write delete_partition_started
>> >
>> > message,
>> >
>> > and RemoteLogCleaner (RLC) instance picks it up for processing. What
>> >
>> > am I
>> >
>> > missing?
>> >
>> > 5016. Under "Topic deletion lifecycle", step (4) is mentioned as "RLC
>> >
>> > gets
>> >
>> > all the remote log segments for the partition and each of these remote
>> >
>> > log
>> >
>> > segments is deleted with the next steps.". Since the RLC instance runs
>> >
>> > on
>> >
>> > each tier topic partition leader, how does the RLC then get the list of
>> > remote log segments to be deleted? It will be useful to add that
>> >
>> > detail to
>> >
>> > the KIP.
>> >
>> > 5017. Under "Public Interfaces -> Configs", there is a line mentioning
>> >
>> > "We
>> >
>> > will support flipping remote.log.storage.enable in next versions." It
>> >
>> > will
>> >
>> > be useful to mention this in the "Future Work" section of the KIP too.
>> >
>> > 5018. The KIP introduces a number of configuration parameters. It will
>> >
>> > be
>> >
>> > useful to mention in the KIP if the user should assume these as static
>> > configuration in the server.properties file, or dynamic configuration
>> >
>> > which
>> >
>> > can be modified without restarting the broker.
>> >
>> > 5019. Maybe this is planned as a future update to the KIP, but I
>> >
>> > thought
>> >
>> > I'd mention it here. Could you please add details to the KIP on why
>> >
>> > RocksDB
>> >
>> > was chosen as the default cache implementation of RLMM, and how it is
>> >
>> > going
>> >
>> > to be used? Were alternatives compared/considered? For example, it
>> >
>> > would be
>> >
>> > useful to explain/evaluate the following: 1) debuggability of the
>> >
>> > RocksDB
>> >
>> > JNI interface, 2) performance, 3) portability across platforms and 4)
>> > interface parity of RocksDB’s JNI api with it's underlying C/C++ api.
>> >
>> > 5020. Following up on (5019), for the RocksDB cache, it will be useful
>> >
>> > to
>> >
>> > explain the relationship/mapping between the following in the KIP: 1)
>> >
>> > # of
>> >
>> > tiered partitions, 2) # of partitions of metadata topic
>> > __remote_log_metadata and 3) # of RocksDB instances. i.e. is the plan
>> >
>> > to
>> >
>> > have a RocksDB instance per tiered partition, or per metadata topic
>> > partition, or just 1 for per broker?
>> >
>> > 5021. I was looking at the implementation prototype (PR link: https://
>> > github.com/apache/kafka/pull/7561). It seems that a boolean attribute
>> is
>> > being introduced into the Log layer to check if remote log capability is
>> > enabled. While the boolean footprint is small at the
>> >
>> > moment,
>> >
>> > this can easily grow in the future and become harder to test/maintain,
>> > considering that the Log layer is already pretty
>> >
>> > complex. We
>> >
>> > should start thinking about how to manage such changes to the Log layer
>> > (for the purpose of improved testability, better separation of
>> >
>> > concerns and
>> >
>> > readability). One proposal I have is to take a step back and define a
>> > higher level Log interface. Then, the Broker code can be changed to use
>> > this interface. It can be changed such that only a handle to the
>> >
>> > interface
>> >
>> > is exposed to other components (such as LogCleaner, ReplicaManager
>> >
>> > etc.)
>> >
>> > and not the underlying Log object. This approach keeps the user of the
>> >
>> > Log
>> >
>> > layer agnostic of the whereabouts of the data. Underneath the
>> >
>> > interface,
>> >
>> > the implementing classes can completely separate local log capabilities
>> > from the remote log. For example, the Log class can be simplified to
>> >
>> > only
>> >
>> > manage logic surrounding local log segments and metadata.
>> >
>> > Additionally, a
>> >
>> > wrapper class can be provided (implementing the higher level Log
>> >
>> > interface)
>> >
>> > which will contain any/all logic surrounding tiered data. The wrapper
>> > class will wrap around an instance of the Log class delegating the
>> >
>> > local
>> >
>> > log logic to it. Finally, a handle to the wrapper class can be exposed
>> >
>> > to
>> >
>> > the other components wherever they need a handle to the higher level
>> >
>> > Log
>> >
>> > interface.
>> >
>> > Cheers,
>> > Kowshik
>> >
>> > On Mon, Oct 26, 2020 at 9:52 PM Satish Duggana <
>> >
>> > satish.duggana@gmail.com>
>> >
>> > wrote:
>> >
>> > Hi,
>> > KIP is updated with 1) topic deletion lifecycle and its related items
>> > 2) Protocol changes(mainly related to ListOffsets) and other minor
>> > changes.
>> > Please go through them and let us know your comments.
>> >
>> > Thanks,
>> > Satish.
>> >
>> > On Mon, Sep 28, 2020 at 9:10 PM Satish Duggana <
>> >
>> > satish.duggana@gmail.com
>> >
>> > wrote:
>> >
>> > Hi Dhruvil,
>> > Thanks for looking into the KIP and sending your comments. Sorry
>> >
>> > for
>> >
>> > the late reply, missed it in the mail thread.
>> >
>> > 1. Could you describe how retention would work with this KIP and
>> >
>> > which
>> >
>> > threads are responsible for driving this work? I believe there are
>> >
>> > 3
>> >
>> > kinds
>> >
>> > of retention processes we are looking at:
>> > (a) Regular retention for data in tiered storage as per
>> >
>> > configured `
>> >
>> > retention.ms` / `retention.bytes`.
>> > (b) Local retention for data in local storage as per configured ` local.
>> > log.retention.ms` / `local.log.retention.bytes`
>> > (c) Possibly regular retention for data in local storage, if the
>> >
>> > tiering
>> >
>> > task is lagging or for data that is below the log start offset.
>> >
>> > Local log retention is done by the existing log cleanup tasks.
>> >
>> > These
>> >
>> > are not done for segments that are not yet copied to remote
>> >
>> > storage.
>> >
>> > Remote log cleanup is done by the leader partition’s RLMTask.
>> >
>> > 2. When does a segment become eligible to be tiered? Is it as soon
>> >
>> > as
>> >
>> > the
>> >
>> > segment is rolled and the end offset is less than the last stable
>> >
>> > offset
>> >
>> > as
>> >
>> > mentioned in the KIP? I wonder if we need to consider other
>> >
>> > parameters
>> >
>> > too,
>> >
>> > like the highwatermark so that we are guaranteed that what we are
>> >
>> > tiering
>> >
>> > has been committed to the log and accepted by the ISR.
>> >
>> > AFAIK, last stable offset is always <= highwatermark. This will
>> >
>> > make
>> >
>> > sure we are always tiering the message segments which have been accepted
>> > by ISR and transactionally completed.
>> >
>> > 3. The section on "Follower Fetch Scenarios" is useful but is a bit
>> > difficult to parse at the moment. It would be useful to summarize
>> >
>> > the
>> >
>> > changes we need in the ReplicaFetcher.
>> >
>> > It may become difficult for users to read/follow if we add code
>> >
>> > changes
>> >
>> > here.
>> >
>> > 4. Related to the above, it's a bit unclear how we are planning on
>> > restoring the producer state for a new replica. Could you expand on
>> >
>> > that?
>> >
>> > It is mentioned in the KIP BuildingRemoteLogAuxState is introduced
>> >
>> > to
>> >
>> > build the state like leader epoch sequence and producer snapshots before
>> > it starts fetching the data from the leader. We will make it clear in
>> the
>> > KIP.
>> >
>> > 5. Similarly, it would be worth summarizing the behavior on unclean
>> >
>> > leader
>> >
>> > election. There are several scenarios to consider here: data loss
>> >
>> > from
>> >
>> > local log, data loss from remote log, data loss from metadata
>> >
>> > topic,
>> >
>> > etc.
>> >
>> > It's worth describing these in detail.
>> >
>> > We mentioned the cases about unclean leader election in the
>> >
>> > follower
>> >
>> > fetch scenarios.
>> > If there are errors while fetching data from remote store or
>> >
>> > metadata
>> >
>> > store, it will work the same way as it works with local log. It returns
>> > the error back to the caller. Please let us know if I am missing your
>> point
>> > here.
>> >
>> > 7. For a READ_COMMITTED FetchRequest, how do we retrieve and
>> >
>> > return the
>> >
>> > aborted transaction metadata?
>> >
>> > When a fetch for a remote log is accessed, we will fetch aborted
>> > transactions along with the segment if it is not found in the local
>> index
>> > cache. This includes the case of transaction index not
>> >
>> > existing
>> >
>> > in the remote log segment. That means, the cache entry can be
>> >
>> > empty or
>> >
>> > have a list of aborted transactions.
>> >
>> > 8. The `LogSegmentData` class assumes that we have a log segment,
>> >
>> > offset
>> >
>> > index, time index, transaction index, producer snapshot and leader
>> >
>> > epoch
>> >
>> > index. How do we deal with cases where we do not have one or more
>> >
>> > of
>> >
>> > these?
>> >
>> > For example, we may not have a transaction index or producer
>> >
>> > snapshot
>> >
>> > for a
>> >
>> > particular segment. The former is optional, and the latter is only
>> >
>> > kept
>> >
>> > for
>> >
>> > up to the 3 latest segments.
>> >
>> > This is a good point, we discussed this in the last meeting. Transaction
>> > index is optional and we will copy them only if it
>> >
>> > exists.
>> >
>> > We want to keep all the producer snapshots at each log segment
>> >
>> > rolling
>> >
>> > and they can be removed if the log copying is successful and it
>> >
>> > still
>> >
>> > maintains the existing latest 3 segments, We only delete the
>> >
>> > producer
>> >
>> > snapshots which have been copied to remote log segments on leader.
>> > Follower will keep the log segments beyond the segments which have
>> >
>> > not
>> >
>> > been copied to remote storage. We will update the KIP with these
>> details.
>> >
>> > Thanks,
>> > Satish.
>> >
>> > On Thu, Sep 17, 2020 at 1:47 AM Dhruvil Shah <dhruvil@confluent.io
>> >
>> > wrote:
>> >
>> > Hi Satish, Harsha,
>> >
>> > Thanks for the KIP. Few questions below:
>> >
>> > 1. Could you describe how retention would work with this KIP and
>> >
>> > which
>> >
>> > threads are responsible for driving this work? I believe there
>> >
>> > are 3
>> >
>> > kinds
>> >
>> > of retention processes we are looking at:
>> > (a) Regular retention for data in tiered storage as per
>> >
>> > configured
>> >
>> > `
>> >
>> > retention.ms` / `retention.bytes`.
>> > (b) Local retention for data in local storage as per
>> >
>> > configured `
>> >
>> > local.log.retention.ms` / `local.log.retention.bytes`
>> > (c) Possibly regular retention for data in local storage, if
>> >
>> > the
>> >
>> > tiering
>> >
>> > task is lagging or for data that is below the log start offset.
>> >
>> > 2. When does a segment become eligible to be tiered? Is it as
>> >
>> > soon as
>> >
>> > the
>> >
>> > segment is rolled and the end offset is less than the last stable
>> >
>> > offset as
>> >
>> > mentioned in the KIP? I wonder if we need to consider other
>> >
>> > parameters
>> >
>> > too,
>> >
>> > like the highwatermark so that we are guaranteed that what we are
>> >
>> > tiering
>> >
>> > has been committed to the log and accepted by the ISR.
>> >
>> > 3. The section on "Follower Fetch Scenarios" is useful but is a
>> >
>> > bit
>> >
>> > difficult to parse at the moment. It would be useful to
>> >
>> > summarize the
>> >
>> > changes we need in the ReplicaFetcher.
>> >
>> > 4. Related to the above, it's a bit unclear how we are planning
>> >
>> > on
>> >
>> > restoring the producer state for a new replica. Could you expand
>> >
>> > on
>> >
>> > that?
>> >
>> > 5. Similarly, it would be worth summarizing the behavior on
>> >
>> > unclean
>> >
>> > leader
>> >
>> > election. There are several scenarios to consider here: data loss
>> >
>> > from
>> >
>> > local log, data loss from remote log, data loss from metadata
>> >
>> > topic,
>> >
>> > etc.
>> >
>> > It's worth describing these in detail.
>> >
>> > 6. It would be useful to add details about how we plan on using
>> >
>> > RocksDB in
>> >
>> > the default implementation of `RemoteLogMetadataManager`.
>> >
>> > 7. For a READ_COMMITTED FetchRequest, how do we retrieve and
>> >
>> > return
>> >
>> > the
>> >
>> > aborted transaction metadata?
>> >
>> > 8. The `LogSegmentData` class assumes that we have a log segment,
>> >
>> > offset
>> >
>> > index, time index, transaction index, producer snapshot and
>> >
>> > leader
>> >
>> > epoch
>> >
>> > index. How do we deal with cases where we do not have one or
>> >
>> > more of
>> >
>> > these?
>> >
>> > For example, we may not have a transaction index or producer
>> >
>> > snapshot
>> >
>> > for a
>> >
>> > particular segment. The former is optional, and the latter is
>> >
>> > only
>> >
>> > kept for
>> >
>> > up to the 3 latest segments.
>> >
>> > Thanks,
>> > Dhruvil
>> >
>> > On Mon, Sep 7, 2020 at 6:54 PM Harsha Ch <ha...@gmail.com>
>> >
>> > wrote:
>> >
>> > Hi All,
>> >
>> > We are all working through the last meeting feedback. I'll
>> >
>> > cancel
>> >
>> > the
>> >
>> > tomorrow 's meeting and we can meanwhile continue our
>> >
>> > discussion in
>> >
>> > mailing
>> >
>> > list. We can start the regular meeting from next week onwards.
>> >
>> > Thanks,
>> >
>> > Harsha
>> >
>> > On Fri, Sep 04, 2020 at 8:41 AM, Satish Duggana <
>> >
>> > satish.duggana@gmail.com
>> >
>> > wrote:
>> >
>> > Hi Jun,
>> > Thanks for your thorough review and comments. Please find the
>> >
>> > inline
>> >
>> > replies below.
>> >
>> > 600. The topic deletion logic needs more details.
>> > 600.1 The KIP mentions "The controller considers the topic
>> >
>> > partition is
>> >
>> > deleted only when it determines that there are no log
>> >
>> > segments
>> >
>> > for
>> >
>> > that
>> >
>> > topic partition by using RLMM". How is this done?
>> >
>> > It uses RLMM#listSegments() returns all the segments for the
>> >
>> > given
>> >
>> > topic
>> >
>> > partition.
>> >
>> > 600.2 "If the delete option is enabled then the leader will
>> >
>> > stop
>> >
>> > RLM task
>> >
>> > and stop processing and it sets all the remote log segment
>> >
>> > metadata of
>> >
>> > that partition with a delete marker and publishes them to
>> >
>> > RLMM."
>> >
>> > We
>> >
>> > discussed this earlier. When a topic is being deleted, there
>> >
>> > may
>> >
>> > not be a
>> >
>> > leader for the deleted partition.
>> >
>> > This is a good point. As suggested in the meeting, we will
>> >
>> > add a
>> >
>> > separate
>> >
>> > section for topic/partition deletion lifecycle and this
>> >
>> > scenario
>> >
>> > will be
>> >
>> > addressed.
>> >
>> > 601. Unclean leader election
>> > 601.1 Scenario 1: new empty follower
>> > After step 1, the follower restores up to offset 3. So why
>> >
>> > does
>> >
>> > it
>> >
>> > have
>> >
>> > LE-2 <https://issues.apache.org/jira/browse/LE-2> <
>> https://issues.apache.org/jira/browse/LE-2> at offset
>> >
>> > 5?
>> >
>> > Nice catch. It was showing the leader epoch fetched from the
>> >
>> > remote
>> >
>> > storage. It should be shown with the truncated till offset 3.
>> >
>> > Updated the
>> >
>> > KIP.
>> >
>> > 601.2 senario 5: After Step 3, leader A has inconsistent data
>> >
>> > between its
>> >
>> > local and the tiered data. For example. offset 3 has msg 3
>> >
>> > LE-0 <https://issues.apache.org/jira/browse/LE-0>
>> >
>> > <https://issues.apache.org/jira/browse/LE-0> locally,
>> >
>> > but msg 5 LE-1 <https://issues.apache.org/jira/browse/LE-1> <
>> https://issues.apache.org/jira/browse/LE-1>
>> >
>> > in
>> >
>> > the remote store. While it's ok for the unclean leader
>> >
>> > to lose data, it should still return consistent data, whether
>> >
>> > it's
>> >
>> > from
>> >
>> > the local or the remote store.
>> >
>> > There is no inconsistency here as LE-0
>> <https://issues.apache.org/jira/browse/LE-0>
>> >
>> > <https://issues.apache.org/jira/browse/LE-0> offsets are [0, 4] and
>> >
>> > LE-2 <https://issues.apache.org/jira/browse/LE-2>
>> >
>> > <https://issues.apache.org/jira/browse/LE-2>:
>> >
>> > [5, ]. It will always get the right records for the given
>> >
>> > offset
>> >
>> > and
>> >
>> > leader epoch. In case of remote, RSM is invoked to get the
>> >
>> > remote
>> >
>> > log
>> >
>> > segment that contains the given offset with the leader epoch.
>> >
>> > 601.4 It seems that retention is based on
>> > listRemoteLogSegments(TopicPartition topicPartition, long
>> >
>> > leaderEpoch).
>> >
>> > When there is an unclean leader election, it's possible for
>> >
>> > the
>> >
>> > new
>> >
>> > leader
>> >
>> > to not to include certain epochs in its epoch cache. How are
>> >
>> > remote
>> >
>> > segments associated with those epochs being cleaned?
>> >
>> > That is a good point. This leader will also cleanup the
>> >
>> > epochs
>> >
>> > earlier to
>> >
>> > its start leader epoch and delete those segments. It gets the
>> >
>> > earliest
>> >
>> > epoch for a partition and starts deleting segments from that
>> >
>> > leader
>> >
>> > epoch.
>> >
>> > We need one more API in RLMM to get the earliest leader
>> >
>> > epoch.
>> >
>> > 601.5 The KIP discusses the handling of unclean leader
>> >
>> > elections
>> >
>> > for user
>> >
>> > topics. What about unclean leader elections on
>> > __remote_log_segment_metadata?
>> > This is the same as other system topics like
>> >
>> > consumer_offsets,
>> >
>> > __transaction_state topics. As discussed in the meeting, we
>> >
>> > will
>> >
>> > add the
>> >
>> > behavior of __remote_log_segment_metadata topic’s unclean
>> >
>> > leader
>> >
>> > truncation.
>> >
>> > 602. It would be useful to clarify the limitations in the
>> >
>> > initial
>> >
>> > release.
>> >
>> > The KIP mentions not supporting compacted topics. What about
>> >
>> > JBOD
>> >
>> > and
>> >
>> > changing the configuration of a topic from delete to compact
>> >
>> > after
>> >
>> > remote.
>> >
>> > log. storage. enable ( http://remote.log.storage.enable/ )
>> >
>> > is
>> >
>> > enabled?
>> >
>> > This was updated in the KIP earlier.
>> >
>> > 603. RLM leader tasks:
>> > 603.1"It checks for rolled over LogSegments (which have the
>> >
>> > last
>> >
>> > message
>> >
>> > offset less than last stable offset of that topic partition)
>> >
>> > and
>> >
>> > copies
>> >
>> > them along with their offset/time/transaction indexes and
>> >
>> > leader
>> >
>> > epoch
>> >
>> > cache to the remote tier." It needs to copy the producer
>> >
>> > snapshot
>> >
>> > too.
>> >
>> > Right. It copies producer snapshots too as mentioned in
>> >
>> > LogSegmentData.
>> >
>> > 603.2 "Local logs are not cleaned up till those segments are
>> >
>> > copied
>> >
>> > successfully to remote even though their retention time/size
>> >
>> > is
>> >
>> > reached"
>> >
>> > This seems weird. If the tiering stops because the remote
>> >
>> > store
>> >
>> > is
>> >
>> > not
>> >
>> > available, we don't want the local data to grow forever.
>> >
>> > It was clarified in the discussion that the comment was more
>> >
>> > about
>> >
>> > the
>> >
>> > local storage goes beyond the log.retention. The above
>> >
>> > statement
>> >
>> > is about
>> >
>> > local.log.retention but not for the complete log.retention.
>> >
>> > When
>> >
>> > it
>> >
>> > reaches the log.retention then it will delete the local logs
>> >
>> > even
>> >
>> > though
>> >
>> > those are not copied to remote storage.
>> >
>> > 604. "RLM maintains a bounded cache(possibly LRU) of the
>> >
>> > index
>> >
>> > files of
>> >
>> > remote log segments to avoid multiple index fetches from the
>> >
>> > remote
>> >
>> > storage. These indexes can be used in the same way as local
>> >
>> > segment
>> >
>> > indexes are used." Could you provide more details on this?
>> >
>> > Are
>> >
>> > the
>> >
>> > indexes
>> >
>> > cached in memory or on disk? If on disk, where are they
>> >
>> > stored?
>> >
>> > Are the
>> >
>> > cached indexes bound by a certain size?
>> >
>> > These are cached on disk and stored in log.dir with a name
>> > “__remote_log_index_cache”. They are bound by the total size.
>> >
>> > This
>> >
>> > will
>> >
>> > be
>> >
>> > exposed as a user configuration,
>> >
>> > 605. BuildingRemoteLogAux
>> > 605.1 In this section, two options are listed. Which one is
>> >
>> > chosen?
>> >
>> > Option-2, updated the KIP.
>> >
>> > 605.2 In option 2, it says "Build the local leader epoch
>> >
>> > cache by
>> >
>> > cutting
>> >
>> > the leader epoch sequence received from remote storage to
>> >
>> > [LSO,
>> >
>> > ELO].
>> >
>> > (LSO
>> >
>> > = log start offset)." We need to do the same thing for the
>> >
>> > producer
>> >
>> > snapshot. However, it's hard to cut the producer snapshot to
>> >
>> > an
>> >
>> > earlier
>> >
>> > offset. Another option is to simply take the lastOffset from
>> >
>> > the
>> >
>> > remote
>> >
>> > segment and use that as the starting fetch offset in the
>> >
>> > follower.
>> >
>> > This
>> >
>> > avoids the need for cutting.
>> >
>> > Right, this was mentioned in the “transactional support”
>> >
>> > section
>> >
>> > about
>> >
>> > adding these details.
>> >
>> > 606. ListOffsets: Since we need a version bump, could you
>> >
>> > document
>> >
>> > it
>> >
>> > under a protocol change section?
>> >
>> > Sure, we will update the KIP.
>> >
>> > 607. "LogStartOffset of a topic can point to either of local
>> >
>> > segment or
>> >
>> > remote segment but it is initialised and maintained in the
>> >
>> > Log
>> >
>> > class like
>> >
>> > now. This is already maintained in `Log` class while loading
>> >
>> > the
>> >
>> > logs and
>> >
>> > it can also be fetched from RemoteLogMetadataManager." What
>> >
>> > will
>> >
>> > happen
>> >
>> > to
>> >
>> > the existing logic (e.g. log recovery) that currently
>> >
>> > depends on
>> >
>> > logStartOffset but assumes it's local?
>> >
>> > They use a field called localLogStartOffset which is the
>> >
>> > local
>> >
>> > log
>> >
>> > start
>> >
>> > offset..
>> >
>> > 608. Handle expired remote segment: How does it pick up new
>> >
>> > logStartOffset
>> >
>> > from deleteRecords?
>> >
>> > Good point. This was not addressed in the KIP. Will update
>> >
>> > the
>> >
>> > KIP
>> >
>> > on how
>> >
>> > the RLM task handles this scenario.
>> >
>> > 609. RLMM message format:
>> > 609.1 It includes both MaxTimestamp and EventTimestamp. Where
>> >
>> > does
>> >
>> > it get
>> >
>> > both since the message in the log only contains one
>> >
>> > timestamp?
>> >
>> > `EventTimeStamp` is the timestamp at which that segment
>> >
>> > metadata
>> >
>> > event is
>> >
>> > generated. This is more for audits.
>> >
>> > 609.2 If we change just the state (e.g. to DELETE_STARTED),
>> >
>> > it
>> >
>> > seems it's
>> >
>> > wasteful to have to include all other fields not changed.
>> >
>> > This is a good point. We thought about incremental updates.
>> >
>> > But
>> >
>> > we
>> >
>> > want
>> >
>> > to
>> >
>> > make sure all the events are in the expected order and take
>> >
>> > action
>> >
>> > based
>> >
>> > on the latest event. Will think through the approaches in
>> >
>> > detail
>> >
>> > and
>> >
>> > update here.
>> >
>> > 609.3 Could you document which process makes the following
>> >
>> > transitions
>> >
>> > DELETE_MARKED, DELETE_STARTED, DELETE_FINISHED?
>> >
>> > Okay, will document more details.
>> >
>> > 610. remote.log.reader.max.pending.tasks: "Maximum remote log
>> >
>> > reader
>> >
>> > thread pool task queue size. If the task queue is full,
>> >
>> > broker
>> >
>> > will stop
>> >
>> > reading remote log segments." What does the broker do if the
>> >
>> > queue
>> >
>> > is
>> >
>> > full?
>> >
>> > It returns an error for this topic partition.
>> >
>> > 611. What do we return if the request offset/epoch doesn't
>> >
>> > exist
>> >
>> > in the
>> >
>> > following API?
>> > RemoteLogSegmentMetadata
>> >
>> > remoteLogSegmentMetadata(TopicPartition
>> >
>> > topicPartition, long offset, int epochForOffset)
>> >
>> > This returns null. But we prefer to update the return type as
>> >
>> > Optional
>> >
>> > and
>> >
>> > return Empty if that does not exist.
>> >
>> > Thanks,
>> > Satish.
>> >
>> > On Tue, Sep 1, 2020 at 9:45 AM Jun Rao < jun@ confluent. io
>> >
>> > (
>> >
>> > jun@confluent.io ) > wrote:
>> >
>> > Hi, Satish,
>> >
>> > Thanks for the updated KIP. Made another pass. A few more
>> >
>> > comments
>> >
>> > below.
>> >
>> > 600. The topic deletion logic needs more details.
>> > 600.1 The KIP mentions "The controller considers the topic
>> >
>> > partition is
>> >
>> > deleted only when it determines that there are no log
>> >
>> > segments
>> >
>> > for that
>> >
>> > topic partition by using RLMM". How is this done? 600.2 "If
>> >
>> > the
>> >
>> > delete
>> >
>> > option is enabled then the leader will stop RLM task and
>> >
>> > stop
>> >
>> > processing
>> >
>> > and it sets all the remote log segment metadata of that
>> >
>> > partition
>> >
>> > with a
>> >
>> > delete marker and publishes them to RLMM." We discussed this
>> >
>> > earlier.
>> >
>> > When
>> >
>> > a topic is being deleted, there may not be a leader for the
>> >
>> > deleted
>> >
>> > partition.
>> >
>> > 601. Unclean leader election
>> > 601.1 Scenario 1: new empty follower
>> > After step 1, the follower restores up to offset 3. So why
>> >
>> > does
>> >
>> > it have
>> >
>> > LE-2 <https://issues.apache.org/jira/browse/LE-2> <
>> https://issues.apache.org/jira/browse/LE-2> at
>> >
>> > offset 5?
>> >
>> > 601.2 senario 5: After Step 3, leader A has inconsistent
>> >
>> > data
>> >
>> > between
>> >
>> > its
>> >
>> > local and the tiered data. For example. offset 3 has msg 3
>> >
>> > LE-0 <https://issues.apache.org/jira/browse/LE-0>
>> >
>> > <https://issues.apache.org/jira/browse/LE-0> locally,
>> >
>> > but msg 5 LE-1 <https://issues.apache.org/jira/browse/LE-1> <
>> https://issues.apache.org/jira/browse/LE-1>
>> >
>> > in
>> >
>> > the remote store. While it's ok for the unclean leader
>> >
>> > to lose data, it should still return consistent data,
>> >
>> > whether
>> >
>> > it's from
>> >
>> > the local or the remote store.
>> > 601.3 The follower picks up log start offset using the
>> >
>> > following
>> >
>> > api.
>> >
>> > Suppose that we have 3 remote segments (LE,
>> >
>> > SegmentStartOffset)
>> >
>> > as (2,
>> >
>> > 10),
>> > (3, 20) and (7, 15) due to an unclean leader election.
>> >
>> > Using the
>> >
>> > following
>> >
>> > api will cause logStartOffset to go backward from 20 to 15.
>> >
>> > How
>> >
>> > do we
>> >
>> > prevent that?
>> > earliestLogOffset(TopicPartition topicPartition, int
>> >
>> > leaderEpoch)
>> >
>> > 601.4
>> >
>> > It
>> >
>> > seems that retention is based on
>> > listRemoteLogSegments(TopicPartition topicPartition, long
>> >
>> > leaderEpoch).
>> >
>> > When there is an unclean leader election, it's possible for
>> >
>> > the
>> >
>> > new
>> >
>> > leader
>> >
>> > to not to include certain epochs in its epoch cache. How are
>> >
>> > remote
>> >
>> > segments associated with those epochs being cleaned? 601.5
>> >
>> > The
>> >
>> > KIP
>> >
>> > discusses the handling of unclean leader elections for user
>> >
>> > topics. What
>> >
>> > about unclean leader elections on
>> > __remote_log_segment_metadata?
>> >
>> > 602. It would be useful to clarify the limitations in the
>> >
>> > initial
>> >
>> > release.
>> >
>> > The KIP mentions not supporting compacted topics. What about
>> >
>> > JBOD
>> >
>> > and
>> >
>> > changing the configuration of a topic from delete to compact
>> >
>> > after
>> >
>> > remote.
>> >
>> > log. storage. enable ( http://remote.log.storage.enable/ )
>> >
>> > is
>> >
>> > enabled?
>> >
>> > 603. RLM leader tasks:
>> > 603.1"It checks for rolled over LogSegments (which have the
>> >
>> > last
>> >
>> > message
>> >
>> > offset less than last stable offset of that topic
>> >
>> > partition) and
>> >
>> > copies
>> >
>> > them along with their offset/time/transaction indexes and
>> >
>> > leader
>> >
>> > epoch
>> >
>> > cache to the remote tier." It needs to copy the producer
>> >
>> > snapshot
>> >
>> > too.
>> >
>> > 603.2 "Local logs are not cleaned up till those segments are
>> >
>> > copied
>> >
>> > successfully to remote even though their retention
>> >
>> > time/size is
>> >
>> > reached"
>> >
>> > This seems weird. If the tiering stops because the remote
>> >
>> > store
>> >
>> > is not
>> >
>> > available, we don't want the local data to grow forever.
>> >
>> > 604. "RLM maintains a bounded cache(possibly LRU) of the
>> >
>> > index
>> >
>> > files of
>> >
>> > remote log segments to avoid multiple index fetches from the
>> >
>> > remote
>> >
>> > storage. These indexes can be used in the same way as local
>> >
>> > segment
>> >
>> > indexes are used." Could you provide more details on this?
>> >
>> > Are
>> >
>> > the
>> >
>> > indexes
>> >
>> > cached in memory or on disk? If on disk, where are they
>> >
>> > stored?
>> >
>> > Are the
>> >
>> > cached indexes bound by a certain size?
>> >
>> > 605. BuildingRemoteLogAux
>> > 605.1 In this section, two options are listed. Which one is
>> >
>> > chosen?
>> >
>> > 605.2
>> >
>> > In option 2, it says "Build the local leader epoch cache by
>> >
>> > cutting the
>> >
>> > leader epoch sequence received from remote storage to [LSO,
>> >
>> > ELO].
>> >
>> > (LSO
>> >
>> > = log start offset)." We need to do the same thing for the
>> >
>> > producer
>> >
>> > snapshot. However, it's hard to cut the producer snapshot
>> >
>> > to an
>> >
>> > earlier
>> >
>> > offset. Another option is to simply take the lastOffset
>> >
>> > from the
>> >
>> > remote
>> >
>> > segment and use that as the starting fetch offset in the
>> >
>> > follower. This
>> >
>> > avoids the need for cutting.
>> >
>> > 606. ListOffsets: Since we need a version bump, could you
>> >
>> > document it
>> >
>> > under a protocol change section?
>> >
>> > 607. "LogStartOffset of a topic can point to either of local
>> >
>> > segment or
>> >
>> > remote segment but it is initialised and maintained in the
>> >
>> > Log
>> >
>> > class
>> >
>> > like
>> >
>> > now. This is already maintained in `Log` class while
>> >
>> > loading the
>> >
>> > logs
>> >
>> > and
>> >
>> > it can also be fetched from RemoteLogMetadataManager." What
>> >
>> > will
>> >
>> > happen
>> >
>> > to
>> >
>> > the existing logic (e.g. log recovery) that currently
>> >
>> > depends on
>> >
>> > logStartOffset but assumes it's local?
>> >
>> > 608. Handle expired remote segment: How does it pick up new
>> >
>> > logStartOffset
>> >
>> > from deleteRecords?
>> >
>> > 609. RLMM message format:
>> > 609.1 It includes both MaxTimestamp and EventTimestamp.
>> >
>> > Where
>> >
>> > does it
>> >
>> > get
>> >
>> > both since the message in the log only contains one
>> >
>> > timestamp?
>> >
>> > 609.2 If
>> >
>> > we
>> >
>> > change just the state (e.g. to DELETE_STARTED), it seems
>> >
>> > it's
>> >
>> > wasteful
>> >
>> > to
>> >
>> > have to include all other fields not changed. 609.3 Could
>> >
>> > you
>> >
>> > document
>> >
>> > which process makes the following transitions DELETE_MARKED,
>> > DELETE_STARTED, DELETE_FINISHED?
>> >
>> > 610. remote.log.reader.max.pending.tasks: "Maximum remote
>> >
>> > log
>> >
>> > reader
>> >
>> > thread pool task queue size. If the task queue is full,
>> >
>> > broker
>> >
>> > will stop
>> >
>> > reading remote log segments." What does the broker do if the
>> >
>> > queue is
>> >
>> > full?
>> >
>> > 611. What do we return if the request offset/epoch doesn't
>> >
>> > exist
>> >
>> > in the
>> >
>> > following API?
>> > RemoteLogSegmentMetadata
>> >
>> > remoteLogSegmentMetadata(TopicPartition
>> >
>> > topicPartition, long offset, int epochForOffset)
>> >
>> > Jun
>> >
>> > On Mon, Aug 31, 2020 at 11:19 AM Satish Duggana < satish.
>> >
>> > duggana@
>> >
>> > gmail. com
>> >
>> > ( satish.duggana@gmail.com ) > wrote:
>> >
>> > KIP is updated with
>> > - Remote log segment metadata topic message format/schema.
>> > - Added remote log segment metadata state transitions and
>> >
>> > explained how
>> >
>> > the deletion of segments is handled, including the case of
>> >
>> > partition
>> >
>> > deletions.
>> > - Added a few more limitations in the "Non goals" section.
>> >
>> > Thanks,
>> > Satish.
>> >
>> > On Thu, Aug 27, 2020 at 12:42 AM Harsha Ch < harsha. ch@
>> >
>> > gmail.
>> >
>> > com (
>> >
>> > harsha.ch@gmail.com ) > wrote:
>> >
>> > Updated the KIP with Meeting Notes section
>> >
>> > https:/ / cwiki. apache. org/ confluence/ display/ KAFKA/
>> >
>> > KIP-405 <https://issues.apache.org/jira/browse/KIP-405> <
>> https://issues.apache.org/jira/browse/KIP-405>
>> >
>> > %3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
>> >
>> > (
>> >
>> > https://cwiki.apache.org/confluence/display/KAFKA/
>> > KIP-405 <https://issues.apache.org/jira/browse/KIP-405>
>> %3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
>> >
>> > )
>> >
>> > On Tue, Aug 25, 2020 at 1:03 PM Jun Rao < jun@
>> >
>> > confluent. io
>> >
>> > (
>> >
>> > jun@confluent.io ) > wrote:
>> >
>> > Hi, Harsha,
>> >
>> > Thanks for the summary. Could you add the summary and the
>> >
>> > recording
>> >
>> > link to
>> >
>> > the last section of
>> >
>> > https:/ / cwiki. apache. org/ confluence/ display/ KAFKA/
>> >
>> > Kafka+Improvement+Proposals
>> >
>> > (
>> >
>> > https://cwiki.apache.org/confluence/display/KAFKA/
>> > Kafka+Improvement+Proposals
>> >
>> > )
>> >
>> > ?
>> >
>> > Jun
>> >
>> > On Tue, Aug 25, 2020 at 11:12 AM Harsha Chintalapani <
>> >
>> > kafka@
>> >
>> > harsha. io (
>> >
>> > kafka@harsha.io ) > wrote:
>> >
>> > Thanks everyone for attending the meeting today.
>> > Here is the recording
>> >
>> > https:/ / drive. google. com/ file/ d/
>> >
>> > 14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/ view?usp=sharing
>> >
>> > (
>> >
>> > https://drive.google.com/file/d/14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/
>> > view?usp=sharing
>> >
>> > )
>> >
>> > Notes:
>> >
>> > 1. KIP is updated with follower fetch protocol and
>> >
>> > ready to
>> >
>> > reviewed
>> >
>> > 2. Satish to capture schema of internal metadata topic
>> >
>> > in
>> >
>> > the
>> >
>> > KIP
>> >
>> > 3. We will update the KIP with details of different
>> >
>> > cases
>> >
>> > 4. Test plan will be captured in a doc and will add to
>> >
>> > the
>> >
>> > KIP
>> >
>> > 5. Add a section "Limitations" to capture the
>> >
>> > capabilities
>> >
>> > that
>> >
>> > will
>> >
>> > be
>> >
>> > introduced with this KIP and what will not be covered in
>> >
>> > this
>> >
>> > KIP.
>> >
>> > Please add to it I missed anything. Will produce a
>> >
>> > formal
>> >
>> > meeting
>> >
>> > notes
>> >
>> > from next meeting onwards.
>> >
>> > Thanks,
>> > Harsha
>> >
>> > On Mon, Aug 24, 2020 at 9:42 PM, Ying Zheng < yingz@
>> >
>> > uber.
>> >
>> > com.
>> >
>> > invalid (
>> >
>> > yingz@uber.com.invalid ) > wrote:
>> >
>> > We did some basic feature tests at Uber. The test
>> >
>> > cases and
>> >
>> > results are
>> >
>> > shared in this google doc:
>> > https:/ / docs. google. com/ spreadsheets/ d/ (
>> > https://docs.google.com/spreadsheets/d/ )
>> >
>> > 1XhNJqjzwXvMCcAOhEH0sSXU6RTvyoSf93DHF-YMfGLk/edit?usp=sharing
>> >
>> > The performance test results were already shared in
>> >
>> > the KIP
>> >
>> > last
>> >
>> > month.
>> >
>> > On Mon, Aug 24, 2020 at 11:10 AM Harsha Ch < harsha.
>> >
>> > ch@
>> >
>> > gmail.
>> >
>> > com (
>> >
>> > harsha.ch@gmail.com ) >
>> >
>> > wrote:
>> >
>> > "Understand commitments towards driving design &
>> >
>> > implementation of
>> >
>> > the
>> >
>> > KIP
>> >
>> > further and how it aligns with participant interests in
>> >
>> > contributing to
>> >
>> > the
>> >
>> > efforts (ex: in the context of Uber’s Q3/Q4 roadmap)."
>> >
>> > What
>> >
>> > is that
>> >
>> > about?
>> >
>> > On Mon, Aug 24, 2020 at 11:05 AM Kowshik Prakasam <
>> >
>> > kprakasam@ confluent. io ( kprakasam@confluent.io ) >
>> >
>> > wrote:
>> >
>> > Hi Harsha,
>> >
>> > The following google doc contains a proposal for
>> >
>> > temporary
>> >
>> > agenda
>> >
>> > for
>> >
>> > the
>> >
>> > KIP-405 <https://issues.apache.org/jira/browse/KIP-405> <
>> https://issues.apache.org/jira/browse/KIP-405>
>> >
>> > <
>> >
>> > https:/ / issues. apache. org/ jira/ browse/ KIP-405
>> <https://issues.apache.org/jira/browse/KIP-405>
>> > <https://issues.apache.org/jira/browse/KIP-405> (
>> >
>> > https://issues.apache.org/jira/browse/KIP-405 ) > sync
>> >
>> > meeting
>> >
>> > tomorrow:
>> >
>> > https:/ / docs. google. com/ document/ d/ (
>> > https://docs.google.com/document/d/ )
>> > 1pqo8X5LU8TpwfC_iqSuVPezhfCfhGkbGN2TqiPA3LBU/edit
>> >
>> > .
>> > Please could you add it to the Google calendar invite?
>> >
>> > Thank you.
>> >
>> > Cheers,
>> > Kowshik
>> >
>> > On Thu, Aug 20, 2020 at 10:58 AM Harsha Ch < harsha.
>> >
>> > ch@
>> >
>> > gmail.
>> >
>> > com (
>> >
>> > harsha.ch@gmail.com ) >
>> >
>> > wrote:
>> >
>> > Hi All,
>> >
>> > Scheduled a meeting for Tuesday 9am - 10am. I can
>> >
>> > record
>> >
>> > and
>> >
>> > upload for
>> >
>> > community to be able to follow the discussion.
>> >
>> > Jun, please add the required folks on confluent side.
>> >
>> > Thanks,
>> >
>> > Harsha
>> >
>> > On Thu, Aug 20, 2020 at 12:33 AM, Alexandre Dupriez <
>> >
>> > alexandre.dupriez@
>> >
>> > gmail. com ( http://gmail.com/ ) > wrote:
>> >
>> > Hi Jun,
>> >
>> > Many thanks for your initiative.
>> >
>> > If you like, I am happy to attend at the time you
>> >
>> > suggested.
>> >
>> > Many thanks,
>> > Alexandre
>> >
>> > Le mer. 19 août 2020 à 22:00, Harsha Ch < harsha. ch@
>> >
>> > gmail. com (
>> >
>> > harsha.
>> >
>> > ch@ gmail. com ( ch@gmail.com ) ) > a écrit :
>> >
>> > Hi Jun,
>> > Thanks. This will help a lot. Tuesday will work for us.
>> > -Harsha
>> >
>> > On Wed, Aug 19, 2020 at 1:24 PM Jun Rao < jun@
>> >
>> > confluent.
>> >
>> > io (
>> >
>> > jun@
>> >
>> > confluent. io ( http://confluent.io/ ) ) > wrote:
>> >
>> > Hi, Satish, Ying, Harsha,
>> >
>> > Do you think it would be useful to have a regular
>> >
>> > virtual
>> >
>> > meeting
>> >
>> > to
>> >
>> > discuss this KIP? The goal of the meeting will be
>> >
>> > sharing
>> >
>> > design/development progress and discussing any open
>> >
>> > issues
>> >
>> > to
>> >
>> > accelerate
>> >
>> > this KIP. If so, will every Tuesday (from next week)
>> >
>> > 9am-10am
>> >
>> > PT
>> >
>> > work for you? I can help set up a Zoom meeting, invite
>> >
>> > everyone who
>> >
>> > might
>> >
>> > be interested, have it recorded and shared, etc.
>> >
>> > Thanks,
>> >
>> > Jun
>> >
>> > On Tue, Aug 18, 2020 at 11:01 AM Satish Duggana <
>> >
>> > satish. duggana@ gmail. com ( satish. duggana@ gmail.
>> >
>> > com
>> >
>> > (
>> >
>> > satish.duggana@gmail.com ) ) >
>> >
>> > wrote:
>> >
>> > Hi Kowshik,
>> >
>> > Thanks for looking into the KIP and sending your
>> >
>> > comments.
>> >
>> > 5001. Under the section "Follower fetch protocol in
>> >
>> > detail",
>> >
>> > the
>> >
>> > next-local-offset is the offset upto which the
>> >
>> > segments are
>> >
>> > copied
>> >
>> >
>>
>

Re: [DISCUSS] KIP-405: Kafka Tiered Storage

[Kowshik Prakasam <kp...@confluent.io>]

Hi Harsha,

The goal we discussed is to aim for preview in AK 3.0. In order to get us
there, it will be useful to think about the order in which the code changes
will be implemented, reviewed and merged. Since you are driving the
development, do you want to layout the order of things? For example, do you
eventually want to break up the PR into multiple smaller ones? If so, you
could list the milestones there. Another perspective is that this can be
helpful to budget time suitably and to understand the progress.
Let us know how we can help.


Cheers,
Kowshik

On Tue, Nov 10, 2020 at 3:26 PM Harsha Chintalapani <ka...@harsha.io> wrote:

> Thanks Kowshik for the link. Seems reasonable,  as we discussed on the
> call, code and completion of this KIP will be taken up by us.
> Regarding Milestone 2, what you think it needs to be clarified there?
> I believe what we are promising in the KIP along with unit tests, systems
> tests will be delivered and we can call that as preview.   We will be
> running this in our production and continue to provide the data and metrics
> to push this feature to GA.
>
>
>
> On Tue, Nov 10, 2020 at 10:07 AM, Kowshik Prakasam <kprakasam@confluent.io
> >
> wrote:
>
> > Hi Harsha/Satish,
> >
> > Thanks for the discussion today. Here is a link to the KIP-405
> <https://issues.apache.org/jira/browse/KIP-405> development
> > milestones google doc we discussed in the meeting today: https://docs.
> > google.com/document/d/1B5_jaZvWWb2DUpgbgImq0k_IPZ4DWrR8Ru7YpuJrXdc/edit
> > . I have shared it with you. Please have a look and share your
> > feedback/improvements. As we discussed, things are clear until milestone
> 1.
> > Beyond that, we can discuss it again (perhaps in next sync or later),
> once
> > you have thought through the implementation plan/milestones and release
> > into preview in 3.0.
> >
> > Cheers,
> > Kowshik
> >
> > On Tue, Nov 10, 2020 at 6:56 AM Satish Duggana <satish.duggana@gmail.com
> >
> > wrote:
> >
> > Hi Jun,
> > Thanks for your comments. Please find the inline replies below.
> >
> > 605.2 "Build the local leader epoch cache by cutting the leader epoch
> > sequence received from remote storage to [LSO, ELO]." I mentioned an
> issue
> > earlier. Suppose the leader's local start offset is 100. The follower
> finds
> > a remote segment covering offset range [80, 120). The producerState with
> > this remote segment is up to offset 120. To trim the producerState to
> > offset 100 requires more work since one needs to download the previous
> > producerState up to offset 80 and then replay the messages from 80 to
> 100.
> > It seems that it's simpler in this case for the follower just to take the
> > remote segment as it is and start fetching from offset 120.
> >
> > We chose that approach to avoid any edge cases here. It may be possible
> > that the remote log segment that is received may not have the same leader
> > epoch sequence from 100-120 as it contains on the leader(this can happen
> > due to unclean leader). It is safe to start from what the leader returns
> > here.Another way is to find the remote log segment
> >
> > 5016. Just to echo what Kowshik was saying. It seems that
> > RLMM.onPartitionLeadershipChanges() is only called on the replicas for a
> > partition, not on the replicas for the __remote_log_segment_metadata
> > partition. It's not clear how the leader of __remote_log_segment_metadata
> > obtains the metadata for remote segments for deletion.
> >
> > RLMM will always receive the callback for the remote log metadata topic
> > partitions hosted on the local broker and these will be subscribed. I
> will
> > make this clear in the KIP.
> >
> > 5100. KIP-516 <https://issues.apache.org/jira/browse/KIP-516> has been
> accepted and is being implemented now. Could you
> > update the KIP based on topicID?
> >
> > We mentioned KIP-516 <https://issues.apache.org/jira/browse/KIP-516>
> and how it helps. We will update this KIP with all
> > the changes it brings with KIP-516
> <https://issues.apache.org/jira/browse/KIP-516>.
> >
> > 5101. RLMM: It would be useful to clarify how the following two APIs are
> > used. According to the wiki, the former is used for topic deletion and
> the
> > latter is used for retention. It seems that retention should use the
> former
> > since remote segments without a matching epoch in the leader (potentially
> > due to unclean leader election) also need to be garbage collected. The
> > latter seems to be used for the new leader to determine the last tiered
> > segment.
> > default Iterator<RemoteLogSegmentMetadata>
> > listRemoteLogSegments(TopicPartition topicPartition)
> > Iterator<RemoteLogSegmentMetadata> listRemoteLogSegments(TopicPartition
> > topicPartition, long leaderEpoch);
> >
> > Right,.that is what we are currently doing. We will update the javadocs
> > and wiki with that. Earlier, we did not want to remove the segments which
> > are not matched with leader epochs from the ladder partition as they may
> be
> > used later by a replica which can become a leader (unclean leader
> election)
> > and refer those segments. But that may leak these segments in remote
> > storage until the topic lifetime. We decided to cleanup the segments with
> > the oldest incase of size based retention also.
> >
> > 5102. RSM:
> > 5102.1 For methods like fetchLogSegmentData(), it seems that they can use
> > RemoteLogSegmentId instead of RemoteLogSegmentMetadata.
> >
> > It will be useful to have metadata for RSM to fetch log segment. It may
> > create location/path using id with other metadata too.
> >
> > 5102.2 In fetchLogSegmentData(), should we use long instead of Long?
> >
> > Wanted to keep endPosition as optional to read till the end of the
> segment
> > and avoid sentinels.
> >
> > 5102.3 Why only some of the methods have default implementation and
> others
> > Don't?
> >
> > Actually, RSM will not have any default implementations. Those 3 methods
> > were made default earlier for tests etc. Updated the wiki.
> >
> > 5102.4. Could we define RemoteLogSegmentMetadataUpdate and
> > DeletePartitionUpdate?
> >
> > Sure, they will be added.
> >
> > 5102.5 LogSegmentData: It seems that it's easier to pass in
> > leaderEpochIndex as a ByteBuffer or byte array than a file since it will
> be
> > generated in memory.
> >
> > Right, this is in plan.
> >
> > 5102.6 RemoteLogSegmentMetadata: It seems that it needs both baseOffset
> > and startOffset. For example, deleteRecords() could move the startOffset
> to
> > the middle of a segment. If we copy the full segment to remote storage,
> the
> > baseOffset and the startOffset will be different.
> >
> > Good point. startOffset is baseOffset by default, if not set explicitly.
> >
> > 5102.7 Could we define all the public methods for
> RemoteLogSegmentMetadata
> > and LogSegmentData?
> >
> > Sure, updated the wiki.
> >
> > 5102.8 Could we document whether endOffset in RemoteLogSegmentMetadata is
> > inclusive/exclusive?
> >
> > It is inclusive, will update.
> >
> > 5103. configs:
> > 5103.1 Could we define the default value of non-required configs (e.g the
> > size of new thread pools)?
> >
> > Sure, that makes sense.
> >
> > 5103.2 It seems that local.log.retention.ms should default to
> retention.ms
> > ,
> > instead of remote.log.retention.minutes. Similarly, it seems that
> > local.log.retention.bytes should default to segment.bytes.
> >
> > Right, we do not have remote.log.retention as we discussed earlier.
> Thanks
> > for catching the typo.
> >
> > 5103.3 remote.log.manager.thread.pool.size: The description says "used in
> > scheduling tasks to copy segments, fetch remote log indexes and clean up
> > remote log segments". However, there is a separate config
> > remote.log.reader.threads for fetching remote data. It's weird to fetch
> > remote index and log in different thread pools since both are used for
> > serving fetch requests.
> >
> > Right, remote.log.manager.thread.pool is mainly used for copy/cleanup
> > activities. Fetch path always goes through remote.log.reader.threads.
> >
> > 5103.4 remote.log.manager.task.interval.ms: Is that the amount of time
> to
> > back off when there is no work to do? If so, perhaps it can be renamed as
> > backoff.ms.
> >
> > This is the delay interval for each iteration. It may be renamed to
> > remote.log.manager.task.delay.ms
> >
> > 5103.5 Are rlm_process_interval_ms and rlm_retry_interval_ms configs? If
> > so, they need to be listed in this section.
> >
> > remote.log.manager.task.interval.ms is the process internal, retry
> > interval is missing in the configs, which will be updated in the KIP.
> >
> > 5104. "RLM maintains a bounded cache(possibly LRU) of the index files of
> > remote log segments to avoid multiple index fetches from the remote
> > storage." Is the RLM in memory or on disk? If on disk, where is it
> stored?
> > Do we need a configuration to bound the size?
> >
> > It is stored on disk. They are stored in a directory
> > `remote-log-index-cache` under log dir. We plan to have a config for that
> > instead of default. We will have a configuration for that.
> >
> > 5105. The KIP uses local-log-start-offset and Earliest Local Offset in
> > different places. It would be useful to standardize the terminology.
> >
> > Sure.
> >
> > 5106. The section on "In BuildingRemoteLogAux state". It listed two
> > options without saying which option is chosen.
> > We already mentioned in the KIP that we chose option-2.
> >
> > 5107. Follower to leader transition: It has step 2, but not step 1.
> Step-1
> > is there but it is not explicitly highlighted. It is previous table to
> > step-2.
> >
> > 5108. If a consumer fetches from the remote data and the remote storage
> is
> > not available, what error code is used in the fetch response?
> >
> > Good point. We have not yet defined the error for this case. We need to
> > define an error message and send the same in fetch response.
> >
> > 5109. "ListOffsets: For timestamps >= 0, it returns the first message
> > offset whose timestamp is >= to the given timestamp in the request. That
> > means it checks in remote log time indexes first, after which local log
> > time indexes are checked." Could you document which method in RLMM is
> used
> > for this?
> >
> > Okay.
> >
> > 5110. Stopreplica: "it sets all the remote log segment metadata of that
> > partition with a delete marker and publishes them to RLMM." This seems
> > outdated given the new topic deletion logic.
> >
> > Will update with KIP-516 <https://issues.apache.org/jira/browse/KIP-516>
> related points.
> >
> > 5111. "RLM follower fetches the earliest offset for the earliest leader
> > epoch by calling RLMM.earliestLogOffset(TopicPartition topicPartition,
> int
> > leaderEpoch) and updates that as the log start offset." Do we need that
> > since replication propagates logStartOffset already?
> >
> > Good point. Right, existing replication protocol takes care of updating
> > the followers’s log start offset received from the leader.
> >
> > 5112. Is the default maxWaitMs of 500ms enough for fetching from remote
> > storage?
> >
> > Remote reads may fail within the current default wait time, but
> subsequent
> > fetches would be able to serve as that data is stored in the local cache.
> > This cache is currently implemented in RSMs. But we plan to pull this
> into
> > the remote log messaging layer in future.
> >
> > 5113. "Committed offsets can be stored in a local file to avoid reading
> > the messages again when a broker is restarted." Could you describe the
> > format and the location of the file? Also, could the same message be
> > processed by RLMM again after broker restart? If so, how do we handle
> that?
> >
> > Sure, we will update in the KIP.
> >
> > 5114. Message format
> > 5114.1 There are two records named RemoteLogSegmentMetadataRecord with
> > apiKey 0 and 1.
> >
> > Nice catch, that was a typo. Fixed in the wiki.
> >
> > 5114.2 RemoteLogSegmentMetadataRecord: Could we document whether
> endOffset
> > is inclusive/exclusive?
> > It is inclusive, will update.
> >
> > 5114.3 RemoteLogSegmentMetadataRecord: Could you explain LeaderEpoch a
> bit
> > more? Is that the epoch of the leader when it copies the segment to
> remote
> > storage? Also, how will this field be used?
> >
> > Right, this is the leader epoch of the broker which copied this segment.
> > This is helpful in reason about which broker copied the segment to remote
> > storage.
> >
> > 5114.4 EventTimestamp: Could you explain this a bit more? Each record in
> > Kafka already has a timestamp field. Could we just use that?
> >
> > This is the timestamp at which the respective event occurred. Added this
> > to RemoteLogSegmentMetadata as RLMM can be any other implementation. We
> > thought about that but it looked cleaner to use at the message structure
> > level instead of getting that from the consumer record and using that to
> > build the respective event.
> >
> > 5114.5 SegmentSizeInBytes: Could this just be int32?
> >
> > Right, it looks like config allows only int value >= 14.
> >
> > 5115. RemoteLogCleaner(RLC): This could be confused with the log cleaner
> > for compaction. Perhaps it can be renamed to sth like
> > RemotePartitionRemover.
> >
> > I am fine with RemotePartitionRemover or RemoteLogDeletionManager(we have
> > other manager classes like RLM, RLMM).
> >
> > 5116. "RLC receives the delete_partition_marked and processes it if it is
> > not yet processed earlier." How does it know whether
> > delete_partition_marked has been processed earlier?
> >
> > This is to handle duplicate delete_partition_marked events. RLC
> internally
> > maintains a state for the delete_partition events and if it already has
> an
> > existing event then it ignores if it is already being processed.
> >
> > 5117. Should we add a new MessageFormatter to read the tier metadata
> > topic?
> >
> > Right, this is in plan but did not mention it in the KIP. This will be
> > useful for debugging purposes too.
> >
> > 5118. "Maximum remote log reader thread pool task queue size. If the task
> > queue is full, broker will stop reading remote log segments." What do we
> > return to the fetch request in this case?
> >
> > We return an error response for that partition.
> >
> > 5119. It would be useful to list all things not supported in the first
> > version in a Future work or Limitations section. For example, compacted
> > topic, JBOD, changing remote.log.storage.enable from true to false, etc.
> >
> > We already have a non-goals section which is filled with some of these
> > details. Do we need another limitations section?
> >
> > Thanks,
> > Satish.
> >
> > On Wed, Nov 4, 2020 at 11:27 PM Jun Rao <ju...@confluent.io> wrote:
> >
> > Hi, Satish,
> >
> > Thanks for the updated KIP. A few more comments below.
> >
> > 605.2 "Build the local leader epoch cache by cutting the leader epoch
> > sequence received from remote storage to [LSO, ELO]." I mentioned an
> >
> > issue
> >
> > earlier. Suppose the leader's local start offset is 100. The follower
> >
> > finds
> >
> > a remote segment covering offset range [80, 120). The producerState with
> > this remote segment is up to offset 120. To trim the producerState to
> > offset 100 requires more work since one needs to download the previous
> > producerState up to offset 80 and then replay the messages from 80 to
> >
> > 100.
> >
> > It seems that it's simpler in this case for the follower just to take the
> > remote segment as it is and start fetching from offset 120.
> >
> > 5016. Just to echo what Kowshik was saying. It seems that
> > RLMM.onPartitionLeadershipChanges() is only called on the replicas for a
> > partition, not on the replicas for the __remote_log_segment_metadata
> > partition. It's not clear how the leader of __remote_log_segment_metadata
> > obtains the metadata for remote segments for deletion.
> >
> > 5100. KIP-516 <https://issues.apache.org/jira/browse/KIP-516> has been
> accepted and is being implemented now. Could you
> > update the KIP based on topicID?
> >
> > 5101. RLMM: It would be useful to clarify how the following two APIs are
> > used. According to the wiki, the former is used for topic deletion and
> >
> > the
> >
> > latter is used for retention. It seems that retention should use the
> >
> > former
> >
> > since remote segments without a matching epoch in the leader (potentially
> > due to unclean leader election) also need to be garbage collected. The
> > latter seems to be used for the new leader to determine the last tiered
> > segment.
> > default Iterator<RemoteLogSegmentMetadata>
> > listRemoteLogSegments(TopicPartition topicPartition)
> > Iterator<RemoteLogSegmentMetadata>
> >
> > listRemoteLogSegments(TopicPartition
> >
> > topicPartition, long leaderEpoch);
> >
> > 5102. RSM:
> > 5102.1 For methods like fetchLogSegmentData(), it seems that they can use
> > RemoteLogSegmentId instead of RemoteLogSegmentMetadata. 5102.2 In
> > fetchLogSegmentData(), should we use long instead of Long? 5102.3 Why
> only
> > some of the methods have default implementation and
> >
> > others
> >
> > don't?
> > 5102.4. Could we define RemoteLogSegmentMetadataUpdate and
> > DeletePartitionUpdate?
> > 5102.5 LogSegmentData: It seems that it's easier to pass in
> > leaderEpochIndex as a ByteBuffer or byte array than a file since it
> >
> > will
> >
> > be generated in memory.
> > 5102.6 RemoteLogSegmentMetadata: It seems that it needs both baseOffset
> >
> > and
> >
> > startOffset. For example, deleteRecords() could move the startOffset to
> >
> > the
> >
> > middle of a segment. If we copy the full segment to remote storage, the
> > baseOffset and the startOffset will be different.
> > 5102.7 Could we define all the public methods for
> >
> > RemoteLogSegmentMetadata
> >
> > and LogSegmentData?
> > 5102.8 Could we document whether endOffset in RemoteLogSegmentMetadata is
> > inclusive/exclusive?
> >
> > 5103. configs:
> > 5103.1 Could we define the default value of non-required configs (e.g the
> > size of new thread pools)?
> > 5103.2 It seems that local.log.retention.ms should default to
> >
> > retention.ms,
> >
> > instead of remote.log.retention.minutes. Similarly, it seems that
> > local.log.retention.bytes should default to segment.bytes. 5103.3
> > remote.log.manager.thread.pool.size: The description says "used in
> > scheduling tasks to copy segments, fetch remote log indexes and clean up
> > remote log segments". However, there is a separate config
> > remote.log.reader.threads for fetching remote data. It's weird to fetch
> > remote index and log in different thread pools since both are used for
> > serving fetch requests.
> > 5103.4 remote.log.manager.task.interval.ms: Is that the amount of time
> >
> > to
> >
> > back off when there is no work to do? If so, perhaps it can be renamed as
> > backoff.ms.
> > 5103.5 Are rlm_process_interval_ms and rlm_retry_interval_ms configs? If
> > so, they need to be listed in this section.
> >
> > 5104. "RLM maintains a bounded cache(possibly LRU) of the index files of
> > remote log segments to avoid multiple index fetches from the remote
> > storage." Is the RLM in memory or on disk? If on disk, where is it
> >
> > stored?
> >
> > Do we need a configuration to bound the size?
> >
> > 5105. The KIP uses local-log-start-offset and Earliest Local Offset in
> > different places. It would be useful to standardize the terminology.
> >
> > 5106. The section on "In BuildingRemoteLogAux state". It listed two
> >
> > options
> >
> > without saying which option is chosen.
> >
> > 5107. Follower to leader transition: It has step 2, but not step 1.
> >
> > 5108. If a consumer fetches from the remote data and the remote storage
> >
> > is
> >
> > not available, what error code is used in the fetch response?
> >
> > 5109. "ListOffsets: For timestamps >= 0, it returns the first message
> > offset whose timestamp is >= to the given timestamp in the request. That
> > means it checks in remote log time indexes first, after which local log
> > time indexes are checked." Could you document which method in RLMM is
> >
> > used
> >
> > for this?
> >
> > 5110. Stopreplica: "it sets all the remote log segment metadata of that
> > partition with a delete marker and publishes them to RLMM." This seems
> > outdated given the new topic deletion logic.
> >
> > 5111. "RLM follower fetches the earliest offset for the earliest leader
> > epoch by calling RLMM.earliestLogOffset(TopicPartition topicPartition,
> >
> > int
> >
> > leaderEpoch) and updates that as the log start offset." Do we need that
> > since replication propagates logStartOffset already?
> >
> > 5112. Is the default maxWaitMs of 500ms enough for fetching from remote
> > storage?
> >
> > 5113. "Committed offsets can be stored in a local file to avoid reading
> >
> > the
> >
> > messages again when a broker is restarted." Could you describe the format
> > and the location of the file? Also, could the same message be processed
> >
> > by
> >
> > RLMM again after broker restart? If so, how do we handle that?
> >
> > 5114. Message format
> > 5114.1 There are two records named RemoteLogSegmentMetadataRecord with
> > apiKey 0 and 1.
> > 5114.2 RemoteLogSegmentMetadataRecord: Could we document whether
> >
> > endOffset
> >
> > is inclusive/exclusive?
> > 5114.3 RemoteLogSegmentMetadataRecord: Could you explain LeaderEpoch a
> >
> > bit
> >
> > more? Is that the epoch of the leader when it copies the segment to
> >
> > remote
> >
> > storage? Also, how will this field be used?
> > 5114.4 EventTimestamp: Could you explain this a bit more? Each record in
> > Kafka already has a timestamp field. Could we just use that? 5114.5
> > SegmentSizeInBytes: Could this just be int32?
> >
> > 5115. RemoteLogCleaner(RLC): This could be confused with the log cleaner
> > for compaction. Perhaps it can be renamed to sth like
> > RemotePartitionRemover.
> >
> > 5116. "RLC receives the delete_partition_marked and processes it if it is
> > not yet processed earlier." How does it know whether
> > delete_partition_marked has been processed earlier?
> >
> > 5117. Should we add a new MessageFormatter to read the tier metadata
> >
> > topic?
> >
> > 5118. "Maximum remote log reader thread pool task queue size. If the task
> > queue is full, broker will stop reading remote log segments." What do we
> > return to the fetch request in this case?
> >
> > 5119. It would be useful to list all things not supported in the first
> > version in a Future work or Limitations section. For example, compacted
> > topic, JBOD, changing remote.log.storage.enable from true to false, etc.
> >
> > Thanks,
> >
> > Jun
> >
> > On Tue, Oct 27, 2020 at 5:57 PM Kowshik Prakasam <kprakasam@confluent.io
> >
> > wrote:
> >
> > Hi Satish,
> >
> > Thanks for the updates to the KIP. Here are my first batch of
> > comments/suggestions on the latest version of the KIP.
> >
> > 5012. In the RemoteStorageManager interface, there is an API defined
> >
> > for
> >
> > each file type. For example, fetchOffsetIndex, fetchTimestampIndex
> >
> > etc. To
> >
> > avoid the duplication, I'd suggest we can instead have a FileType enum
> >
> > and
> >
> > a common get API based on the FileType.
> >
> > 5013. There are some references to the Google doc in the KIP. I wasn't
> >
> > sure
> >
> > if the Google doc is expected to be in sync with the contents of the
> >
> > wiki.
> >
> > Going forward, it seems easier if just the KIP is maintained as the
> >
> > source
> >
> > of truth. In this regard, could you please move all the references to
> >
> > the
> >
> > Google doc, maybe to a separate References section at the bottom of the
> > KIP?
> >
> > 5014. There are some TODO sections in the KIP. Would these be filled
> >
> > up in
> >
> > future iterations?
> >
> > 5015. Under "Topic deletion lifecycle", I'm trying to understand why
> >
> > do we
> >
> > need delete_partition_marked as well as the delete_partition_started
> > messages. I couldn't spot a drawback if supposing we simplified the
> >
> > design
> >
> > such that the controller would only write delete_partition_started
> >
> > message,
> >
> > and RemoteLogCleaner (RLC) instance picks it up for processing. What
> >
> > am I
> >
> > missing?
> >
> > 5016. Under "Topic deletion lifecycle", step (4) is mentioned as "RLC
> >
> > gets
> >
> > all the remote log segments for the partition and each of these remote
> >
> > log
> >
> > segments is deleted with the next steps.". Since the RLC instance runs
> >
> > on
> >
> > each tier topic partition leader, how does the RLC then get the list of
> > remote log segments to be deleted? It will be useful to add that
> >
> > detail to
> >
> > the KIP.
> >
> > 5017. Under "Public Interfaces -> Configs", there is a line mentioning
> >
> > "We
> >
> > will support flipping remote.log.storage.enable in next versions." It
> >
> > will
> >
> > be useful to mention this in the "Future Work" section of the KIP too.
> >
> > 5018. The KIP introduces a number of configuration parameters. It will
> >
> > be
> >
> > useful to mention in the KIP if the user should assume these as static
> > configuration in the server.properties file, or dynamic configuration
> >
> > which
> >
> > can be modified without restarting the broker.
> >
> > 5019. Maybe this is planned as a future update to the KIP, but I
> >
> > thought
> >
> > I'd mention it here. Could you please add details to the KIP on why
> >
> > RocksDB
> >
> > was chosen as the default cache implementation of RLMM, and how it is
> >
> > going
> >
> > to be used? Were alternatives compared/considered? For example, it
> >
> > would be
> >
> > useful to explain/evaluate the following: 1) debuggability of the
> >
> > RocksDB
> >
> > JNI interface, 2) performance, 3) portability across platforms and 4)
> > interface parity of RocksDB’s JNI api with it's underlying C/C++ api.
> >
> > 5020. Following up on (5019), for the RocksDB cache, it will be useful
> >
> > to
> >
> > explain the relationship/mapping between the following in the KIP: 1)
> >
> > # of
> >
> > tiered partitions, 2) # of partitions of metadata topic
> > __remote_log_metadata and 3) # of RocksDB instances. i.e. is the plan
> >
> > to
> >
> > have a RocksDB instance per tiered partition, or per metadata topic
> > partition, or just 1 for per broker?
> >
> > 5021. I was looking at the implementation prototype (PR link: https://
> > github.com/apache/kafka/pull/7561). It seems that a boolean attribute is
> > being introduced into the Log layer to check if remote log capability is
> > enabled. While the boolean footprint is small at the
> >
> > moment,
> >
> > this can easily grow in the future and become harder to test/maintain,
> > considering that the Log layer is already pretty
> >
> > complex. We
> >
> > should start thinking about how to manage such changes to the Log layer
> > (for the purpose of improved testability, better separation of
> >
> > concerns and
> >
> > readability). One proposal I have is to take a step back and define a
> > higher level Log interface. Then, the Broker code can be changed to use
> > this interface. It can be changed such that only a handle to the
> >
> > interface
> >
> > is exposed to other components (such as LogCleaner, ReplicaManager
> >
> > etc.)
> >
> > and not the underlying Log object. This approach keeps the user of the
> >
> > Log
> >
> > layer agnostic of the whereabouts of the data. Underneath the
> >
> > interface,
> >
> > the implementing classes can completely separate local log capabilities
> > from the remote log. For example, the Log class can be simplified to
> >
> > only
> >
> > manage logic surrounding local log segments and metadata.
> >
> > Additionally, a
> >
> > wrapper class can be provided (implementing the higher level Log
> >
> > interface)
> >
> > which will contain any/all logic surrounding tiered data. The wrapper
> > class will wrap around an instance of the Log class delegating the
> >
> > local
> >
> > log logic to it. Finally, a handle to the wrapper class can be exposed
> >
> > to
> >
> > the other components wherever they need a handle to the higher level
> >
> > Log
> >
> > interface.
> >
> > Cheers,
> > Kowshik
> >
> > On Mon, Oct 26, 2020 at 9:52 PM Satish Duggana <
> >
> > satish.duggana@gmail.com>
> >
> > wrote:
> >
> > Hi,
> > KIP is updated with 1) topic deletion lifecycle and its related items
> > 2) Protocol changes(mainly related to ListOffsets) and other minor
> > changes.
> > Please go through them and let us know your comments.
> >
> > Thanks,
> > Satish.
> >
> > On Mon, Sep 28, 2020 at 9:10 PM Satish Duggana <
> >
> > satish.duggana@gmail.com
> >
> > wrote:
> >
> > Hi Dhruvil,
> > Thanks for looking into the KIP and sending your comments. Sorry
> >
> > for
> >
> > the late reply, missed it in the mail thread.
> >
> > 1. Could you describe how retention would work with this KIP and
> >
> > which
> >
> > threads are responsible for driving this work? I believe there are
> >
> > 3
> >
> > kinds
> >
> > of retention processes we are looking at:
> > (a) Regular retention for data in tiered storage as per
> >
> > configured `
> >
> > retention.ms` / `retention.bytes`.
> > (b) Local retention for data in local storage as per configured ` local.
> > log.retention.ms` / `local.log.retention.bytes`
> > (c) Possibly regular retention for data in local storage, if the
> >
> > tiering
> >
> > task is lagging or for data that is below the log start offset.
> >
> > Local log retention is done by the existing log cleanup tasks.
> >
> > These
> >
> > are not done for segments that are not yet copied to remote
> >
> > storage.
> >
> > Remote log cleanup is done by the leader partition’s RLMTask.
> >
> > 2. When does a segment become eligible to be tiered? Is it as soon
> >
> > as
> >
> > the
> >
> > segment is rolled and the end offset is less than the last stable
> >
> > offset
> >
> > as
> >
> > mentioned in the KIP? I wonder if we need to consider other
> >
> > parameters
> >
> > too,
> >
> > like the highwatermark so that we are guaranteed that what we are
> >
> > tiering
> >
> > has been committed to the log and accepted by the ISR.
> >
> > AFAIK, last stable offset is always <= highwatermark. This will
> >
> > make
> >
> > sure we are always tiering the message segments which have been accepted
> > by ISR and transactionally completed.
> >
> > 3. The section on "Follower Fetch Scenarios" is useful but is a bit
> > difficult to parse at the moment. It would be useful to summarize
> >
> > the
> >
> > changes we need in the ReplicaFetcher.
> >
> > It may become difficult for users to read/follow if we add code
> >
> > changes
> >
> > here.
> >
> > 4. Related to the above, it's a bit unclear how we are planning on
> > restoring the producer state for a new replica. Could you expand on
> >
> > that?
> >
> > It is mentioned in the KIP BuildingRemoteLogAuxState is introduced
> >
> > to
> >
> > build the state like leader epoch sequence and producer snapshots before
> > it starts fetching the data from the leader. We will make it clear in the
> > KIP.
> >
> > 5. Similarly, it would be worth summarizing the behavior on unclean
> >
> > leader
> >
> > election. There are several scenarios to consider here: data loss
> >
> > from
> >
> > local log, data loss from remote log, data loss from metadata
> >
> > topic,
> >
> > etc.
> >
> > It's worth describing these in detail.
> >
> > We mentioned the cases about unclean leader election in the
> >
> > follower
> >
> > fetch scenarios.
> > If there are errors while fetching data from remote store or
> >
> > metadata
> >
> > store, it will work the same way as it works with local log. It returns
> > the error back to the caller. Please let us know if I am missing your
> point
> > here.
> >
> > 7. For a READ_COMMITTED FetchRequest, how do we retrieve and
> >
> > return the
> >
> > aborted transaction metadata?
> >
> > When a fetch for a remote log is accessed, we will fetch aborted
> > transactions along with the segment if it is not found in the local index
> > cache. This includes the case of transaction index not
> >
> > existing
> >
> > in the remote log segment. That means, the cache entry can be
> >
> > empty or
> >
> > have a list of aborted transactions.
> >
> > 8. The `LogSegmentData` class assumes that we have a log segment,
> >
> > offset
> >
> > index, time index, transaction index, producer snapshot and leader
> >
> > epoch
> >
> > index. How do we deal with cases where we do not have one or more
> >
> > of
> >
> > these?
> >
> > For example, we may not have a transaction index or producer
> >
> > snapshot
> >
> > for a
> >
> > particular segment. The former is optional, and the latter is only
> >
> > kept
> >
> > for
> >
> > up to the 3 latest segments.
> >
> > This is a good point, we discussed this in the last meeting. Transaction
> > index is optional and we will copy them only if it
> >
> > exists.
> >
> > We want to keep all the producer snapshots at each log segment
> >
> > rolling
> >
> > and they can be removed if the log copying is successful and it
> >
> > still
> >
> > maintains the existing latest 3 segments, We only delete the
> >
> > producer
> >
> > snapshots which have been copied to remote log segments on leader.
> > Follower will keep the log segments beyond the segments which have
> >
> > not
> >
> > been copied to remote storage. We will update the KIP with these details.
> >
> > Thanks,
> > Satish.
> >
> > On Thu, Sep 17, 2020 at 1:47 AM Dhruvil Shah <dhruvil@confluent.io
> >
> > wrote:
> >
> > Hi Satish, Harsha,
> >
> > Thanks for the KIP. Few questions below:
> >
> > 1. Could you describe how retention would work with this KIP and
> >
> > which
> >
> > threads are responsible for driving this work? I believe there
> >
> > are 3
> >
> > kinds
> >
> > of retention processes we are looking at:
> > (a) Regular retention for data in tiered storage as per
> >
> > configured
> >
> > `
> >
> > retention.ms` / `retention.bytes`.
> > (b) Local retention for data in local storage as per
> >
> > configured `
> >
> > local.log.retention.ms` / `local.log.retention.bytes`
> > (c) Possibly regular retention for data in local storage, if
> >
> > the
> >
> > tiering
> >
> > task is lagging or for data that is below the log start offset.
> >
> > 2. When does a segment become eligible to be tiered? Is it as
> >
> > soon as
> >
> > the
> >
> > segment is rolled and the end offset is less than the last stable
> >
> > offset as
> >
> > mentioned in the KIP? I wonder if we need to consider other
> >
> > parameters
> >
> > too,
> >
> > like the highwatermark so that we are guaranteed that what we are
> >
> > tiering
> >
> > has been committed to the log and accepted by the ISR.
> >
> > 3. The section on "Follower Fetch Scenarios" is useful but is a
> >
> > bit
> >
> > difficult to parse at the moment. It would be useful to
> >
> > summarize the
> >
> > changes we need in the ReplicaFetcher.
> >
> > 4. Related to the above, it's a bit unclear how we are planning
> >
> > on
> >
> > restoring the producer state for a new replica. Could you expand
> >
> > on
> >
> > that?
> >
> > 5. Similarly, it would be worth summarizing the behavior on
> >
> > unclean
> >
> > leader
> >
> > election. There are several scenarios to consider here: data loss
> >
> > from
> >
> > local log, data loss from remote log, data loss from metadata
> >
> > topic,
> >
> > etc.
> >
> > It's worth describing these in detail.
> >
> > 6. It would be useful to add details about how we plan on using
> >
> > RocksDB in
> >
> > the default implementation of `RemoteLogMetadataManager`.
> >
> > 7. For a READ_COMMITTED FetchRequest, how do we retrieve and
> >
> > return
> >
> > the
> >
> > aborted transaction metadata?
> >
> > 8. The `LogSegmentData` class assumes that we have a log segment,
> >
> > offset
> >
> > index, time index, transaction index, producer snapshot and
> >
> > leader
> >
> > epoch
> >
> > index. How do we deal with cases where we do not have one or
> >
> > more of
> >
> > these?
> >
> > For example, we may not have a transaction index or producer
> >
> > snapshot
> >
> > for a
> >
> > particular segment. The former is optional, and the latter is
> >
> > only
> >
> > kept for
> >
> > up to the 3 latest segments.
> >
> > Thanks,
> > Dhruvil
> >
> > On Mon, Sep 7, 2020 at 6:54 PM Harsha Ch <ha...@gmail.com>
> >
> > wrote:
> >
> > Hi All,
> >
> > We are all working through the last meeting feedback. I'll
> >
> > cancel
> >
> > the
> >
> > tomorrow 's meeting and we can meanwhile continue our
> >
> > discussion in
> >
> > mailing
> >
> > list. We can start the regular meeting from next week onwards.
> >
> > Thanks,
> >
> > Harsha
> >
> > On Fri, Sep 04, 2020 at 8:41 AM, Satish Duggana <
> >
> > satish.duggana@gmail.com
> >
> > wrote:
> >
> > Hi Jun,
> > Thanks for your thorough review and comments. Please find the
> >
> > inline
> >
> > replies below.
> >
> > 600. The topic deletion logic needs more details.
> > 600.1 The KIP mentions "The controller considers the topic
> >
> > partition is
> >
> > deleted only when it determines that there are no log
> >
> > segments
> >
> > for
> >
> > that
> >
> > topic partition by using RLMM". How is this done?
> >
> > It uses RLMM#listSegments() returns all the segments for the
> >
> > given
> >
> > topic
> >
> > partition.
> >
> > 600.2 "If the delete option is enabled then the leader will
> >
> > stop
> >
> > RLM task
> >
> > and stop processing and it sets all the remote log segment
> >
> > metadata of
> >
> > that partition with a delete marker and publishes them to
> >
> > RLMM."
> >
> > We
> >
> > discussed this earlier. When a topic is being deleted, there
> >
> > may
> >
> > not be a
> >
> > leader for the deleted partition.
> >
> > This is a good point. As suggested in the meeting, we will
> >
> > add a
> >
> > separate
> >
> > section for topic/partition deletion lifecycle and this
> >
> > scenario
> >
> > will be
> >
> > addressed.
> >
> > 601. Unclean leader election
> > 601.1 Scenario 1: new empty follower
> > After step 1, the follower restores up to offset 3. So why
> >
> > does
> >
> > it
> >
> > have
> >
> > LE-2 <https://issues.apache.org/jira/browse/LE-2> <
> https://issues.apache.org/jira/browse/LE-2> at offset
> >
> > 5?
> >
> > Nice catch. It was showing the leader epoch fetched from the
> >
> > remote
> >
> > storage. It should be shown with the truncated till offset 3.
> >
> > Updated the
> >
> > KIP.
> >
> > 601.2 senario 5: After Step 3, leader A has inconsistent data
> >
> > between its
> >
> > local and the tiered data. For example. offset 3 has msg 3
> >
> > LE-0 <https://issues.apache.org/jira/browse/LE-0>
> >
> > <https://issues.apache.org/jira/browse/LE-0> locally,
> >
> > but msg 5 LE-1 <https://issues.apache.org/jira/browse/LE-1> <
> https://issues.apache.org/jira/browse/LE-1>
> >
> > in
> >
> > the remote store. While it's ok for the unclean leader
> >
> > to lose data, it should still return consistent data, whether
> >
> > it's
> >
> > from
> >
> > the local or the remote store.
> >
> > There is no inconsistency here as LE-0
> <https://issues.apache.org/jira/browse/LE-0>
> >
> > <https://issues.apache.org/jira/browse/LE-0> offsets are [0, 4] and
> >
> > LE-2 <https://issues.apache.org/jira/browse/LE-2>
> >
> > <https://issues.apache.org/jira/browse/LE-2>:
> >
> > [5, ]. It will always get the right records for the given
> >
> > offset
> >
> > and
> >
> > leader epoch. In case of remote, RSM is invoked to get the
> >
> > remote
> >
> > log
> >
> > segment that contains the given offset with the leader epoch.
> >
> > 601.4 It seems that retention is based on
> > listRemoteLogSegments(TopicPartition topicPartition, long
> >
> > leaderEpoch).
> >
> > When there is an unclean leader election, it's possible for
> >
> > the
> >
> > new
> >
> > leader
> >
> > to not to include certain epochs in its epoch cache. How are
> >
> > remote
> >
> > segments associated with those epochs being cleaned?
> >
> > That is a good point. This leader will also cleanup the
> >
> > epochs
> >
> > earlier to
> >
> > its start leader epoch and delete those segments. It gets the
> >
> > earliest
> >
> > epoch for a partition and starts deleting segments from that
> >
> > leader
> >
> > epoch.
> >
> > We need one more API in RLMM to get the earliest leader
> >
> > epoch.
> >
> > 601.5 The KIP discusses the handling of unclean leader
> >
> > elections
> >
> > for user
> >
> > topics. What about unclean leader elections on
> > __remote_log_segment_metadata?
> > This is the same as other system topics like
> >
> > consumer_offsets,
> >
> > __transaction_state topics. As discussed in the meeting, we
> >
> > will
> >
> > add the
> >
> > behavior of __remote_log_segment_metadata topic’s unclean
> >
> > leader
> >
> > truncation.
> >
> > 602. It would be useful to clarify the limitations in the
> >
> > initial
> >
> > release.
> >
> > The KIP mentions not supporting compacted topics. What about
> >
> > JBOD
> >
> > and
> >
> > changing the configuration of a topic from delete to compact
> >
> > after
> >
> > remote.
> >
> > log. storage. enable ( http://remote.log.storage.enable/ )
> >
> > is
> >
> > enabled?
> >
> > This was updated in the KIP earlier.
> >
> > 603. RLM leader tasks:
> > 603.1"It checks for rolled over LogSegments (which have the
> >
> > last
> >
> > message
> >
> > offset less than last stable offset of that topic partition)
> >
> > and
> >
> > copies
> >
> > them along with their offset/time/transaction indexes and
> >
> > leader
> >
> > epoch
> >
> > cache to the remote tier." It needs to copy the producer
> >
> > snapshot
> >
> > too.
> >
> > Right. It copies producer snapshots too as mentioned in
> >
> > LogSegmentData.
> >
> > 603.2 "Local logs are not cleaned up till those segments are
> >
> > copied
> >
> > successfully to remote even though their retention time/size
> >
> > is
> >
> > reached"
> >
> > This seems weird. If the tiering stops because the remote
> >
> > store
> >
> > is
> >
> > not
> >
> > available, we don't want the local data to grow forever.
> >
> > It was clarified in the discussion that the comment was more
> >
> > about
> >
> > the
> >
> > local storage goes beyond the log.retention. The above
> >
> > statement
> >
> > is about
> >
> > local.log.retention but not for the complete log.retention.
> >
> > When
> >
> > it
> >
> > reaches the log.retention then it will delete the local logs
> >
> > even
> >
> > though
> >
> > those are not copied to remote storage.
> >
> > 604. "RLM maintains a bounded cache(possibly LRU) of the
> >
> > index
> >
> > files of
> >
> > remote log segments to avoid multiple index fetches from the
> >
> > remote
> >
> > storage. These indexes can be used in the same way as local
> >
> > segment
> >
> > indexes are used." Could you provide more details on this?
> >
> > Are
> >
> > the
> >
> > indexes
> >
> > cached in memory or on disk? If on disk, where are they
> >
> > stored?
> >
> > Are the
> >
> > cached indexes bound by a certain size?
> >
> > These are cached on disk and stored in log.dir with a name
> > “__remote_log_index_cache”. They are bound by the total size.
> >
> > This
> >
> > will
> >
> > be
> >
> > exposed as a user configuration,
> >
> > 605. BuildingRemoteLogAux
> > 605.1 In this section, two options are listed. Which one is
> >
> > chosen?
> >
> > Option-2, updated the KIP.
> >
> > 605.2 In option 2, it says "Build the local leader epoch
> >
> > cache by
> >
> > cutting
> >
> > the leader epoch sequence received from remote storage to
> >
> > [LSO,
> >
> > ELO].
> >
> > (LSO
> >
> > = log start offset)." We need to do the same thing for the
> >
> > producer
> >
> > snapshot. However, it's hard to cut the producer snapshot to
> >
> > an
> >
> > earlier
> >
> > offset. Another option is to simply take the lastOffset from
> >
> > the
> >
> > remote
> >
> > segment and use that as the starting fetch offset in the
> >
> > follower.
> >
> > This
> >
> > avoids the need for cutting.
> >
> > Right, this was mentioned in the “transactional support”
> >
> > section
> >
> > about
> >
> > adding these details.
> >
> > 606. ListOffsets: Since we need a version bump, could you
> >
> > document
> >
> > it
> >
> > under a protocol change section?
> >
> > Sure, we will update the KIP.
> >
> > 607. "LogStartOffset of a topic can point to either of local
> >
> > segment or
> >
> > remote segment but it is initialised and maintained in the
> >
> > Log
> >
> > class like
> >
> > now. This is already maintained in `Log` class while loading
> >
> > the
> >
> > logs and
> >
> > it can also be fetched from RemoteLogMetadataManager." What
> >
> > will
> >
> > happen
> >
> > to
> >
> > the existing logic (e.g. log recovery) that currently
> >
> > depends on
> >
> > logStartOffset but assumes it's local?
> >
> > They use a field called localLogStartOffset which is the
> >
> > local
> >
> > log
> >
> > start
> >
> > offset..
> >
> > 608. Handle expired remote segment: How does it pick up new
> >
> > logStartOffset
> >
> > from deleteRecords?
> >
> > Good point. This was not addressed in the KIP. Will update
> >
> > the
> >
> > KIP
> >
> > on how
> >
> > the RLM task handles this scenario.
> >
> > 609. RLMM message format:
> > 609.1 It includes both MaxTimestamp and EventTimestamp. Where
> >
> > does
> >
> > it get
> >
> > both since the message in the log only contains one
> >
> > timestamp?
> >
> > `EventTimeStamp` is the timestamp at which that segment
> >
> > metadata
> >
> > event is
> >
> > generated. This is more for audits.
> >
> > 609.2 If we change just the state (e.g. to DELETE_STARTED),
> >
> > it
> >
> > seems it's
> >
> > wasteful to have to include all other fields not changed.
> >
> > This is a good point. We thought about incremental updates.
> >
> > But
> >
> > we
> >
> > want
> >
> > to
> >
> > make sure all the events are in the expected order and take
> >
> > action
> >
> > based
> >
> > on the latest event. Will think through the approaches in
> >
> > detail
> >
> > and
> >
> > update here.
> >
> > 609.3 Could you document which process makes the following
> >
> > transitions
> >
> > DELETE_MARKED, DELETE_STARTED, DELETE_FINISHED?
> >
> > Okay, will document more details.
> >
> > 610. remote.log.reader.max.pending.tasks: "Maximum remote log
> >
> > reader
> >
> > thread pool task queue size. If the task queue is full,
> >
> > broker
> >
> > will stop
> >
> > reading remote log segments." What does the broker do if the
> >
> > queue
> >
> > is
> >
> > full?
> >
> > It returns an error for this topic partition.
> >
> > 611. What do we return if the request offset/epoch doesn't
> >
> > exist
> >
> > in the
> >
> > following API?
> > RemoteLogSegmentMetadata
> >
> > remoteLogSegmentMetadata(TopicPartition
> >
> > topicPartition, long offset, int epochForOffset)
> >
> > This returns null. But we prefer to update the return type as
> >
> > Optional
> >
> > and
> >
> > return Empty if that does not exist.
> >
> > Thanks,
> > Satish.
> >
> > On Tue, Sep 1, 2020 at 9:45 AM Jun Rao < jun@ confluent. io
> >
> > (
> >
> > jun@confluent.io ) > wrote:
> >
> > Hi, Satish,
> >
> > Thanks for the updated KIP. Made another pass. A few more
> >
> > comments
> >
> > below.
> >
> > 600. The topic deletion logic needs more details.
> > 600.1 The KIP mentions "The controller considers the topic
> >
> > partition is
> >
> > deleted only when it determines that there are no log
> >
> > segments
> >
> > for that
> >
> > topic partition by using RLMM". How is this done? 600.2 "If
> >
> > the
> >
> > delete
> >
> > option is enabled then the leader will stop RLM task and
> >
> > stop
> >
> > processing
> >
> > and it sets all the remote log segment metadata of that
> >
> > partition
> >
> > with a
> >
> > delete marker and publishes them to RLMM." We discussed this
> >
> > earlier.
> >
> > When
> >
> > a topic is being deleted, there may not be a leader for the
> >
> > deleted
> >
> > partition.
> >
> > 601. Unclean leader election
> > 601.1 Scenario 1: new empty follower
> > After step 1, the follower restores up to offset 3. So why
> >
> > does
> >
> > it have
> >
> > LE-2 <https://issues.apache.org/jira/browse/LE-2> <
> https://issues.apache.org/jira/browse/LE-2> at
> >
> > offset 5?
> >
> > 601.2 senario 5: After Step 3, leader A has inconsistent
> >
> > data
> >
> > between
> >
> > its
> >
> > local and the tiered data. For example. offset 3 has msg 3
> >
> > LE-0 <https://issues.apache.org/jira/browse/LE-0>
> >
> > <https://issues.apache.org/jira/browse/LE-0> locally,
> >
> > but msg 5 LE-1 <https://issues.apache.org/jira/browse/LE-1> <
> https://issues.apache.org/jira/browse/LE-1>
> >
> > in
> >
> > the remote store. While it's ok for the unclean leader
> >
> > to lose data, it should still return consistent data,
> >
> > whether
> >
> > it's from
> >
> > the local or the remote store.
> > 601.3 The follower picks up log start offset using the
> >
> > following
> >
> > api.
> >
> > Suppose that we have 3 remote segments (LE,
> >
> > SegmentStartOffset)
> >
> > as (2,
> >
> > 10),
> > (3, 20) and (7, 15) due to an unclean leader election.
> >
> > Using the
> >
> > following
> >
> > api will cause logStartOffset to go backward from 20 to 15.
> >
> > How
> >
> > do we
> >
> > prevent that?
> > earliestLogOffset(TopicPartition topicPartition, int
> >
> > leaderEpoch)
> >
> > 601.4
> >
> > It
> >
> > seems that retention is based on
> > listRemoteLogSegments(TopicPartition topicPartition, long
> >
> > leaderEpoch).
> >
> > When there is an unclean leader election, it's possible for
> >
> > the
> >
> > new
> >
> > leader
> >
> > to not to include certain epochs in its epoch cache. How are
> >
> > remote
> >
> > segments associated with those epochs being cleaned? 601.5
> >
> > The
> >
> > KIP
> >
> > discusses the handling of unclean leader elections for user
> >
> > topics. What
> >
> > about unclean leader elections on
> > __remote_log_segment_metadata?
> >
> > 602. It would be useful to clarify the limitations in the
> >
> > initial
> >
> > release.
> >
> > The KIP mentions not supporting compacted topics. What about
> >
> > JBOD
> >
> > and
> >
> > changing the configuration of a topic from delete to compact
> >
> > after
> >
> > remote.
> >
> > log. storage. enable ( http://remote.log.storage.enable/ )
> >
> > is
> >
> > enabled?
> >
> > 603. RLM leader tasks:
> > 603.1"It checks for rolled over LogSegments (which have the
> >
> > last
> >
> > message
> >
> > offset less than last stable offset of that topic
> >
> > partition) and
> >
> > copies
> >
> > them along with their offset/time/transaction indexes and
> >
> > leader
> >
> > epoch
> >
> > cache to the remote tier." It needs to copy the producer
> >
> > snapshot
> >
> > too.
> >
> > 603.2 "Local logs are not cleaned up till those segments are
> >
> > copied
> >
> > successfully to remote even though their retention
> >
> > time/size is
> >
> > reached"
> >
> > This seems weird. If the tiering stops because the remote
> >
> > store
> >
> > is not
> >
> > available, we don't want the local data to grow forever.
> >
> > 604. "RLM maintains a bounded cache(possibly LRU) of the
> >
> > index
> >
> > files of
> >
> > remote log segments to avoid multiple index fetches from the
> >
> > remote
> >
> > storage. These indexes can be used in the same way as local
> >
> > segment
> >
> > indexes are used." Could you provide more details on this?
> >
> > Are
> >
> > the
> >
> > indexes
> >
> > cached in memory or on disk? If on disk, where are they
> >
> > stored?
> >
> > Are the
> >
> > cached indexes bound by a certain size?
> >
> > 605. BuildingRemoteLogAux
> > 605.1 In this section, two options are listed. Which one is
> >
> > chosen?
> >
> > 605.2
> >
> > In option 2, it says "Build the local leader epoch cache by
> >
> > cutting the
> >
> > leader epoch sequence received from remote storage to [LSO,
> >
> > ELO].
> >
> > (LSO
> >
> > = log start offset)." We need to do the same thing for the
> >
> > producer
> >
> > snapshot. However, it's hard to cut the producer snapshot
> >
> > to an
> >
> > earlier
> >
> > offset. Another option is to simply take the lastOffset
> >
> > from the
> >
> > remote
> >
> > segment and use that as the starting fetch offset in the
> >
> > follower. This
> >
> > avoids the need for cutting.
> >
> > 606. ListOffsets: Since we need a version bump, could you
> >
> > document it
> >
> > under a protocol change section?
> >
> > 607. "LogStartOffset of a topic can point to either of local
> >
> > segment or
> >
> > remote segment but it is initialised and maintained in the
> >
> > Log
> >
> > class
> >
> > like
> >
> > now. This is already maintained in `Log` class while
> >
> > loading the
> >
> > logs
> >
> > and
> >
> > it can also be fetched from RemoteLogMetadataManager." What
> >
> > will
> >
> > happen
> >
> > to
> >
> > the existing logic (e.g. log recovery) that currently
> >
> > depends on
> >
> > logStartOffset but assumes it's local?
> >
> > 608. Handle expired remote segment: How does it pick up new
> >
> > logStartOffset
> >
> > from deleteRecords?
> >
> > 609. RLMM message format:
> > 609.1 It includes both MaxTimestamp and EventTimestamp.
> >
> > Where
> >
> > does it
> >
> > get
> >
> > both since the message in the log only contains one
> >
> > timestamp?
> >
> > 609.2 If
> >
> > we
> >
> > change just the state (e.g. to DELETE_STARTED), it seems
> >
> > it's
> >
> > wasteful
> >
> > to
> >
> > have to include all other fields not changed. 609.3 Could
> >
> > you
> >
> > document
> >
> > which process makes the following transitions DELETE_MARKED,
> > DELETE_STARTED, DELETE_FINISHED?
> >
> > 610. remote.log.reader.max.pending.tasks: "Maximum remote
> >
> > log
> >
> > reader
> >
> > thread pool task queue size. If the task queue is full,
> >
> > broker
> >
> > will stop
> >
> > reading remote log segments." What does the broker do if the
> >
> > queue is
> >
> > full?
> >
> > 611. What do we return if the request offset/epoch doesn't
> >
> > exist
> >
> > in the
> >
> > following API?
> > RemoteLogSegmentMetadata
> >
> > remoteLogSegmentMetadata(TopicPartition
> >
> > topicPartition, long offset, int epochForOffset)
> >
> > Jun
> >
> > On Mon, Aug 31, 2020 at 11:19 AM Satish Duggana < satish.
> >
> > duggana@
> >
> > gmail. com
> >
> > ( satish.duggana@gmail.com ) > wrote:
> >
> > KIP is updated with
> > - Remote log segment metadata topic message format/schema.
> > - Added remote log segment metadata state transitions and
> >
> > explained how
> >
> > the deletion of segments is handled, including the case of
> >
> > partition
> >
> > deletions.
> > - Added a few more limitations in the "Non goals" section.
> >
> > Thanks,
> > Satish.
> >
> > On Thu, Aug 27, 2020 at 12:42 AM Harsha Ch < harsha. ch@
> >
> > gmail.
> >
> > com (
> >
> > harsha.ch@gmail.com ) > wrote:
> >
> > Updated the KIP with Meeting Notes section
> >
> > https:/ / cwiki. apache. org/ confluence/ display/ KAFKA/
> >
> > KIP-405 <https://issues.apache.org/jira/browse/KIP-405> <
> https://issues.apache.org/jira/browse/KIP-405>
> >
> > %3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> >
> > (
> >
> > https://cwiki.apache.org/confluence/display/KAFKA/
> > KIP-405 <https://issues.apache.org/jira/browse/KIP-405>
> %3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> >
> > )
> >
> > On Tue, Aug 25, 2020 at 1:03 PM Jun Rao < jun@
> >
> > confluent. io
> >
> > (
> >
> > jun@confluent.io ) > wrote:
> >
> > Hi, Harsha,
> >
> > Thanks for the summary. Could you add the summary and the
> >
> > recording
> >
> > link to
> >
> > the last section of
> >
> > https:/ / cwiki. apache. org/ confluence/ display/ KAFKA/
> >
> > Kafka+Improvement+Proposals
> >
> > (
> >
> > https://cwiki.apache.org/confluence/display/KAFKA/
> > Kafka+Improvement+Proposals
> >
> > )
> >
> > ?
> >
> > Jun
> >
> > On Tue, Aug 25, 2020 at 11:12 AM Harsha Chintalapani <
> >
> > kafka@
> >
> > harsha. io (
> >
> > kafka@harsha.io ) > wrote:
> >
> > Thanks everyone for attending the meeting today.
> > Here is the recording
> >
> > https:/ / drive. google. com/ file/ d/
> >
> > 14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/ view?usp=sharing
> >
> > (
> >
> > https://drive.google.com/file/d/14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/
> > view?usp=sharing
> >
> > )
> >
> > Notes:
> >
> > 1. KIP is updated with follower fetch protocol and
> >
> > ready to
> >
> > reviewed
> >
> > 2. Satish to capture schema of internal metadata topic
> >
> > in
> >
> > the
> >
> > KIP
> >
> > 3. We will update the KIP with details of different
> >
> > cases
> >
> > 4. Test plan will be captured in a doc and will add to
> >
> > the
> >
> > KIP
> >
> > 5. Add a section "Limitations" to capture the
> >
> > capabilities
> >
> > that
> >
> > will
> >
> > be
> >
> > introduced with this KIP and what will not be covered in
> >
> > this
> >
> > KIP.
> >
> > Please add to it I missed anything. Will produce a
> >
> > formal
> >
> > meeting
> >
> > notes
> >
> > from next meeting onwards.
> >
> > Thanks,
> > Harsha
> >
> > On Mon, Aug 24, 2020 at 9:42 PM, Ying Zheng < yingz@
> >
> > uber.
> >
> > com.
> >
> > invalid (
> >
> > yingz@uber.com.invalid ) > wrote:
> >
> > We did some basic feature tests at Uber. The test
> >
> > cases and
> >
> > results are
> >
> > shared in this google doc:
> > https:/ / docs. google. com/ spreadsheets/ d/ (
> > https://docs.google.com/spreadsheets/d/ )
> >
> > 1XhNJqjzwXvMCcAOhEH0sSXU6RTvyoSf93DHF-YMfGLk/edit?usp=sharing
> >
> > The performance test results were already shared in
> >
> > the KIP
> >
> > last
> >
> > month.
> >
> > On Mon, Aug 24, 2020 at 11:10 AM Harsha Ch < harsha.
> >
> > ch@
> >
> > gmail.
> >
> > com (
> >
> > harsha.ch@gmail.com ) >
> >
> > wrote:
> >
> > "Understand commitments towards driving design &
> >
> > implementation of
> >
> > the
> >
> > KIP
> >
> > further and how it aligns with participant interests in
> >
> > contributing to
> >
> > the
> >
> > efforts (ex: in the context of Uber’s Q3/Q4 roadmap)."
> >
> > What
> >
> > is that
> >
> > about?
> >
> > On Mon, Aug 24, 2020 at 11:05 AM Kowshik Prakasam <
> >
> > kprakasam@ confluent. io ( kprakasam@confluent.io ) >
> >
> > wrote:
> >
> > Hi Harsha,
> >
> > The following google doc contains a proposal for
> >
> > temporary
> >
> > agenda
> >
> > for
> >
> > the
> >
> > KIP-405 <https://issues.apache.org/jira/browse/KIP-405> <
> https://issues.apache.org/jira/browse/KIP-405>
> >
> > <
> >
> > https:/ / issues. apache. org/ jira/ browse/ KIP-405
> <https://issues.apache.org/jira/browse/KIP-405>
> > <https://issues.apache.org/jira/browse/KIP-405> (
> >
> > https://issues.apache.org/jira/browse/KIP-405 ) > sync
> >
> > meeting
> >
> > tomorrow:
> >
> > https:/ / docs. google. com/ document/ d/ (
> > https://docs.google.com/document/d/ )
> > 1pqo8X5LU8TpwfC_iqSuVPezhfCfhGkbGN2TqiPA3LBU/edit
> >
> > .
> > Please could you add it to the Google calendar invite?
> >
> > Thank you.
> >
> > Cheers,
> > Kowshik
> >
> > On Thu, Aug 20, 2020 at 10:58 AM Harsha Ch < harsha.
> >
> > ch@
> >
> > gmail.
> >
> > com (
> >
> > harsha.ch@gmail.com ) >
> >
> > wrote:
> >
> > Hi All,
> >
> > Scheduled a meeting for Tuesday 9am - 10am. I can
> >
> > record
> >
> > and
> >
> > upload for
> >
> > community to be able to follow the discussion.
> >
> > Jun, please add the required folks on confluent side.
> >
> > Thanks,
> >
> > Harsha
> >
> > On Thu, Aug 20, 2020 at 12:33 AM, Alexandre Dupriez <
> >
> > alexandre.dupriez@
> >
> > gmail. com ( http://gmail.com/ ) > wrote:
> >
> > Hi Jun,
> >
> > Many thanks for your initiative.
> >
> > If you like, I am happy to attend at the time you
> >
> > suggested.
> >
> > Many thanks,
> > Alexandre
> >
> > Le mer. 19 août 2020 à 22:00, Harsha Ch < harsha. ch@
> >
> > gmail. com (
> >
> > harsha.
> >
> > ch@ gmail. com ( ch@gmail.com ) ) > a écrit :
> >
> > Hi Jun,
> > Thanks. This will help a lot. Tuesday will work for us.
> > -Harsha
> >
> > On Wed, Aug 19, 2020 at 1:24 PM Jun Rao < jun@
> >
> > confluent.
> >
> > io (
> >
> > jun@
> >
> > confluent. io ( http://confluent.io/ ) ) > wrote:
> >
> > Hi, Satish, Ying, Harsha,
> >
> > Do you think it would be useful to have a regular
> >
> > virtual
> >
> > meeting
> >
> > to
> >
> > discuss this KIP? The goal of the meeting will be
> >
> > sharing
> >
> > design/development progress and discussing any open
> >
> > issues
> >
> > to
> >
> > accelerate
> >
> > this KIP. If so, will every Tuesday (from next week)
> >
> > 9am-10am
> >
> > PT
> >
> > work for you? I can help set up a Zoom meeting, invite
> >
> > everyone who
> >
> > might
> >
> > be interested, have it recorded and shared, etc.
> >
> > Thanks,
> >
> > Jun
> >
> > On Tue, Aug 18, 2020 at 11:01 AM Satish Duggana <
> >
> > satish. duggana@ gmail. com ( satish. duggana@ gmail.
> >
> > com
> >
> > (
> >
> > satish.duggana@gmail.com ) ) >
> >
> > wrote:
> >
> > Hi Kowshik,
> >
> > Thanks for looking into the KIP and sending your
> >
> > comments.
> >
> > 5001. Under the section "Follower fetch protocol in
> >
> > detail",
> >
> > the
> >
> > next-local-offset is the offset upto which the
> >
> > segments are
> >
> > copied
> >
> >
>

Re: [DISCUSS] KIP-405: Kafka Tiered Storage

[Harsha Chintalapani <ka...@harsha.io>]

Thanks Kowshik for the link. Seems reasonable,  as we discussed on the
call, code and completion of this KIP will be taken up by us.
Regarding Milestone 2, what you think it needs to be clarified there?
I believe what we are promising in the KIP along with unit tests, systems
tests will be delivered and we can call that as preview.   We will be
running this in our production and continue to provide the data and metrics
to push this feature to GA.



On Tue, Nov 10, 2020 at 10:07 AM, Kowshik Prakasam <kp...@confluent.io>
wrote:

> Hi Harsha/Satish,
>
> Thanks for the discussion today. Here is a link to the KIP-405 development
> milestones google doc we discussed in the meeting today: https://docs.
> google.com/document/d/1B5_jaZvWWb2DUpgbgImq0k_IPZ4DWrR8Ru7YpuJrXdc/edit
> . I have shared it with you. Please have a look and share your
> feedback/improvements. As we discussed, things are clear until milestone 1.
> Beyond that, we can discuss it again (perhaps in next sync or later), once
> you have thought through the implementation plan/milestones and release
> into preview in 3.0.
>
> Cheers,
> Kowshik
>
> On Tue, Nov 10, 2020 at 6:56 AM Satish Duggana <sa...@gmail.com>
> wrote:
>
> Hi Jun,
> Thanks for your comments. Please find the inline replies below.
>
> 605.2 "Build the local leader epoch cache by cutting the leader epoch
> sequence received from remote storage to [LSO, ELO]." I mentioned an issue
> earlier. Suppose the leader's local start offset is 100. The follower finds
> a remote segment covering offset range [80, 120). The producerState with
> this remote segment is up to offset 120. To trim the producerState to
> offset 100 requires more work since one needs to download the previous
> producerState up to offset 80 and then replay the messages from 80 to 100.
> It seems that it's simpler in this case for the follower just to take the
> remote segment as it is and start fetching from offset 120.
>
> We chose that approach to avoid any edge cases here. It may be possible
> that the remote log segment that is received may not have the same leader
> epoch sequence from 100-120 as it contains on the leader(this can happen
> due to unclean leader). It is safe to start from what the leader returns
> here.Another way is to find the remote log segment
>
> 5016. Just to echo what Kowshik was saying. It seems that
> RLMM.onPartitionLeadershipChanges() is only called on the replicas for a
> partition, not on the replicas for the __remote_log_segment_metadata
> partition. It's not clear how the leader of __remote_log_segment_metadata
> obtains the metadata for remote segments for deletion.
>
> RLMM will always receive the callback for the remote log metadata topic
> partitions hosted on the local broker and these will be subscribed. I will
> make this clear in the KIP.
>
> 5100. KIP-516 has been accepted and is being implemented now. Could you
> update the KIP based on topicID?
>
> We mentioned KIP-516 and how it helps. We will update this KIP with all
> the changes it brings with KIP-516.
>
> 5101. RLMM: It would be useful to clarify how the following two APIs are
> used. According to the wiki, the former is used for topic deletion and the
> latter is used for retention. It seems that retention should use the former
> since remote segments without a matching epoch in the leader (potentially
> due to unclean leader election) also need to be garbage collected. The
> latter seems to be used for the new leader to determine the last tiered
> segment.
> default Iterator<RemoteLogSegmentMetadata>
> listRemoteLogSegments(TopicPartition topicPartition)
> Iterator<RemoteLogSegmentMetadata> listRemoteLogSegments(TopicPartition
> topicPartition, long leaderEpoch);
>
> Right,.that is what we are currently doing. We will update the javadocs
> and wiki with that. Earlier, we did not want to remove the segments which
> are not matched with leader epochs from the ladder partition as they may be
> used later by a replica which can become a leader (unclean leader election)
> and refer those segments. But that may leak these segments in remote
> storage until the topic lifetime. We decided to cleanup the segments with
> the oldest incase of size based retention also.
>
> 5102. RSM:
> 5102.1 For methods like fetchLogSegmentData(), it seems that they can use
> RemoteLogSegmentId instead of RemoteLogSegmentMetadata.
>
> It will be useful to have metadata for RSM to fetch log segment. It may
> create location/path using id with other metadata too.
>
> 5102.2 In fetchLogSegmentData(), should we use long instead of Long?
>
> Wanted to keep endPosition as optional to read till the end of the segment
> and avoid sentinels.
>
> 5102.3 Why only some of the methods have default implementation and others
> Don't?
>
> Actually, RSM will not have any default implementations. Those 3 methods
> were made default earlier for tests etc. Updated the wiki.
>
> 5102.4. Could we define RemoteLogSegmentMetadataUpdate and
> DeletePartitionUpdate?
>
> Sure, they will be added.
>
> 5102.5 LogSegmentData: It seems that it's easier to pass in
> leaderEpochIndex as a ByteBuffer or byte array than a file since it will be
> generated in memory.
>
> Right, this is in plan.
>
> 5102.6 RemoteLogSegmentMetadata: It seems that it needs both baseOffset
> and startOffset. For example, deleteRecords() could move the startOffset to
> the middle of a segment. If we copy the full segment to remote storage, the
> baseOffset and the startOffset will be different.
>
> Good point. startOffset is baseOffset by default, if not set explicitly.
>
> 5102.7 Could we define all the public methods for RemoteLogSegmentMetadata
> and LogSegmentData?
>
> Sure, updated the wiki.
>
> 5102.8 Could we document whether endOffset in RemoteLogSegmentMetadata is
> inclusive/exclusive?
>
> It is inclusive, will update.
>
> 5103. configs:
> 5103.1 Could we define the default value of non-required configs (e.g the
> size of new thread pools)?
>
> Sure, that makes sense.
>
> 5103.2 It seems that local.log.retention.ms should default to retention.ms
> ,
> instead of remote.log.retention.minutes. Similarly, it seems that
> local.log.retention.bytes should default to segment.bytes.
>
> Right, we do not have remote.log.retention as we discussed earlier. Thanks
> for catching the typo.
>
> 5103.3 remote.log.manager.thread.pool.size: The description says "used in
> scheduling tasks to copy segments, fetch remote log indexes and clean up
> remote log segments". However, there is a separate config
> remote.log.reader.threads for fetching remote data. It's weird to fetch
> remote index and log in different thread pools since both are used for
> serving fetch requests.
>
> Right, remote.log.manager.thread.pool is mainly used for copy/cleanup
> activities. Fetch path always goes through remote.log.reader.threads.
>
> 5103.4 remote.log.manager.task.interval.ms: Is that the amount of time to
> back off when there is no work to do? If so, perhaps it can be renamed as
> backoff.ms.
>
> This is the delay interval for each iteration. It may be renamed to
> remote.log.manager.task.delay.ms
>
> 5103.5 Are rlm_process_interval_ms and rlm_retry_interval_ms configs? If
> so, they need to be listed in this section.
>
> remote.log.manager.task.interval.ms is the process internal, retry
> interval is missing in the configs, which will be updated in the KIP.
>
> 5104. "RLM maintains a bounded cache(possibly LRU) of the index files of
> remote log segments to avoid multiple index fetches from the remote
> storage." Is the RLM in memory or on disk? If on disk, where is it stored?
> Do we need a configuration to bound the size?
>
> It is stored on disk. They are stored in a directory
> `remote-log-index-cache` under log dir. We plan to have a config for that
> instead of default. We will have a configuration for that.
>
> 5105. The KIP uses local-log-start-offset and Earliest Local Offset in
> different places. It would be useful to standardize the terminology.
>
> Sure.
>
> 5106. The section on "In BuildingRemoteLogAux state". It listed two
> options without saying which option is chosen.
> We already mentioned in the KIP that we chose option-2.
>
> 5107. Follower to leader transition: It has step 2, but not step 1. Step-1
> is there but it is not explicitly highlighted. It is previous table to
> step-2.
>
> 5108. If a consumer fetches from the remote data and the remote storage is
> not available, what error code is used in the fetch response?
>
> Good point. We have not yet defined the error for this case. We need to
> define an error message and send the same in fetch response.
>
> 5109. "ListOffsets: For timestamps >= 0, it returns the first message
> offset whose timestamp is >= to the given timestamp in the request. That
> means it checks in remote log time indexes first, after which local log
> time indexes are checked." Could you document which method in RLMM is used
> for this?
>
> Okay.
>
> 5110. Stopreplica: "it sets all the remote log segment metadata of that
> partition with a delete marker and publishes them to RLMM." This seems
> outdated given the new topic deletion logic.
>
> Will update with KIP-516 related points.
>
> 5111. "RLM follower fetches the earliest offset for the earliest leader
> epoch by calling RLMM.earliestLogOffset(TopicPartition topicPartition, int
> leaderEpoch) and updates that as the log start offset." Do we need that
> since replication propagates logStartOffset already?
>
> Good point. Right, existing replication protocol takes care of updating
> the followers’s log start offset received from the leader.
>
> 5112. Is the default maxWaitMs of 500ms enough for fetching from remote
> storage?
>
> Remote reads may fail within the current default wait time, but subsequent
> fetches would be able to serve as that data is stored in the local cache.
> This cache is currently implemented in RSMs. But we plan to pull this into
> the remote log messaging layer in future.
>
> 5113. "Committed offsets can be stored in a local file to avoid reading
> the messages again when a broker is restarted." Could you describe the
> format and the location of the file? Also, could the same message be
> processed by RLMM again after broker restart? If so, how do we handle that?
>
> Sure, we will update in the KIP.
>
> 5114. Message format
> 5114.1 There are two records named RemoteLogSegmentMetadataRecord with
> apiKey 0 and 1.
>
> Nice catch, that was a typo. Fixed in the wiki.
>
> 5114.2 RemoteLogSegmentMetadataRecord: Could we document whether endOffset
> is inclusive/exclusive?
> It is inclusive, will update.
>
> 5114.3 RemoteLogSegmentMetadataRecord: Could you explain LeaderEpoch a bit
> more? Is that the epoch of the leader when it copies the segment to remote
> storage? Also, how will this field be used?
>
> Right, this is the leader epoch of the broker which copied this segment.
> This is helpful in reason about which broker copied the segment to remote
> storage.
>
> 5114.4 EventTimestamp: Could you explain this a bit more? Each record in
> Kafka already has a timestamp field. Could we just use that?
>
> This is the timestamp at which the respective event occurred. Added this
> to RemoteLogSegmentMetadata as RLMM can be any other implementation. We
> thought about that but it looked cleaner to use at the message structure
> level instead of getting that from the consumer record and using that to
> build the respective event.
>
> 5114.5 SegmentSizeInBytes: Could this just be int32?
>
> Right, it looks like config allows only int value >= 14.
>
> 5115. RemoteLogCleaner(RLC): This could be confused with the log cleaner
> for compaction. Perhaps it can be renamed to sth like
> RemotePartitionRemover.
>
> I am fine with RemotePartitionRemover or RemoteLogDeletionManager(we have
> other manager classes like RLM, RLMM).
>
> 5116. "RLC receives the delete_partition_marked and processes it if it is
> not yet processed earlier." How does it know whether
> delete_partition_marked has been processed earlier?
>
> This is to handle duplicate delete_partition_marked events. RLC internally
> maintains a state for the delete_partition events and if it already has an
> existing event then it ignores if it is already being processed.
>
> 5117. Should we add a new MessageFormatter to read the tier metadata
> topic?
>
> Right, this is in plan but did not mention it in the KIP. This will be
> useful for debugging purposes too.
>
> 5118. "Maximum remote log reader thread pool task queue size. If the task
> queue is full, broker will stop reading remote log segments." What do we
> return to the fetch request in this case?
>
> We return an error response for that partition.
>
> 5119. It would be useful to list all things not supported in the first
> version in a Future work or Limitations section. For example, compacted
> topic, JBOD, changing remote.log.storage.enable from true to false, etc.
>
> We already have a non-goals section which is filled with some of these
> details. Do we need another limitations section?
>
> Thanks,
> Satish.
>
> On Wed, Nov 4, 2020 at 11:27 PM Jun Rao <ju...@confluent.io> wrote:
>
> Hi, Satish,
>
> Thanks for the updated KIP. A few more comments below.
>
> 605.2 "Build the local leader epoch cache by cutting the leader epoch
> sequence received from remote storage to [LSO, ELO]." I mentioned an
>
> issue
>
> earlier. Suppose the leader's local start offset is 100. The follower
>
> finds
>
> a remote segment covering offset range [80, 120). The producerState with
> this remote segment is up to offset 120. To trim the producerState to
> offset 100 requires more work since one needs to download the previous
> producerState up to offset 80 and then replay the messages from 80 to
>
> 100.
>
> It seems that it's simpler in this case for the follower just to take the
> remote segment as it is and start fetching from offset 120.
>
> 5016. Just to echo what Kowshik was saying. It seems that
> RLMM.onPartitionLeadershipChanges() is only called on the replicas for a
> partition, not on the replicas for the __remote_log_segment_metadata
> partition. It's not clear how the leader of __remote_log_segment_metadata
> obtains the metadata for remote segments for deletion.
>
> 5100. KIP-516 has been accepted and is being implemented now. Could you
> update the KIP based on topicID?
>
> 5101. RLMM: It would be useful to clarify how the following two APIs are
> used. According to the wiki, the former is used for topic deletion and
>
> the
>
> latter is used for retention. It seems that retention should use the
>
> former
>
> since remote segments without a matching epoch in the leader (potentially
> due to unclean leader election) also need to be garbage collected. The
> latter seems to be used for the new leader to determine the last tiered
> segment.
> default Iterator<RemoteLogSegmentMetadata>
> listRemoteLogSegments(TopicPartition topicPartition)
> Iterator<RemoteLogSegmentMetadata>
>
> listRemoteLogSegments(TopicPartition
>
> topicPartition, long leaderEpoch);
>
> 5102. RSM:
> 5102.1 For methods like fetchLogSegmentData(), it seems that they can use
> RemoteLogSegmentId instead of RemoteLogSegmentMetadata. 5102.2 In
> fetchLogSegmentData(), should we use long instead of Long? 5102.3 Why only
> some of the methods have default implementation and
>
> others
>
> don't?
> 5102.4. Could we define RemoteLogSegmentMetadataUpdate and
> DeletePartitionUpdate?
> 5102.5 LogSegmentData: It seems that it's easier to pass in
> leaderEpochIndex as a ByteBuffer or byte array than a file since it
>
> will
>
> be generated in memory.
> 5102.6 RemoteLogSegmentMetadata: It seems that it needs both baseOffset
>
> and
>
> startOffset. For example, deleteRecords() could move the startOffset to
>
> the
>
> middle of a segment. If we copy the full segment to remote storage, the
> baseOffset and the startOffset will be different.
> 5102.7 Could we define all the public methods for
>
> RemoteLogSegmentMetadata
>
> and LogSegmentData?
> 5102.8 Could we document whether endOffset in RemoteLogSegmentMetadata is
> inclusive/exclusive?
>
> 5103. configs:
> 5103.1 Could we define the default value of non-required configs (e.g the
> size of new thread pools)?
> 5103.2 It seems that local.log.retention.ms should default to
>
> retention.ms,
>
> instead of remote.log.retention.minutes. Similarly, it seems that
> local.log.retention.bytes should default to segment.bytes. 5103.3
> remote.log.manager.thread.pool.size: The description says "used in
> scheduling tasks to copy segments, fetch remote log indexes and clean up
> remote log segments". However, there is a separate config
> remote.log.reader.threads for fetching remote data. It's weird to fetch
> remote index and log in different thread pools since both are used for
> serving fetch requests.
> 5103.4 remote.log.manager.task.interval.ms: Is that the amount of time
>
> to
>
> back off when there is no work to do? If so, perhaps it can be renamed as
> backoff.ms.
> 5103.5 Are rlm_process_interval_ms and rlm_retry_interval_ms configs? If
> so, they need to be listed in this section.
>
> 5104. "RLM maintains a bounded cache(possibly LRU) of the index files of
> remote log segments to avoid multiple index fetches from the remote
> storage." Is the RLM in memory or on disk? If on disk, where is it
>
> stored?
>
> Do we need a configuration to bound the size?
>
> 5105. The KIP uses local-log-start-offset and Earliest Local Offset in
> different places. It would be useful to standardize the terminology.
>
> 5106. The section on "In BuildingRemoteLogAux state". It listed two
>
> options
>
> without saying which option is chosen.
>
> 5107. Follower to leader transition: It has step 2, but not step 1.
>
> 5108. If a consumer fetches from the remote data and the remote storage
>
> is
>
> not available, what error code is used in the fetch response?
>
> 5109. "ListOffsets: For timestamps >= 0, it returns the first message
> offset whose timestamp is >= to the given timestamp in the request. That
> means it checks in remote log time indexes first, after which local log
> time indexes are checked." Could you document which method in RLMM is
>
> used
>
> for this?
>
> 5110. Stopreplica: "it sets all the remote log segment metadata of that
> partition with a delete marker and publishes them to RLMM." This seems
> outdated given the new topic deletion logic.
>
> 5111. "RLM follower fetches the earliest offset for the earliest leader
> epoch by calling RLMM.earliestLogOffset(TopicPartition topicPartition,
>
> int
>
> leaderEpoch) and updates that as the log start offset." Do we need that
> since replication propagates logStartOffset already?
>
> 5112. Is the default maxWaitMs of 500ms enough for fetching from remote
> storage?
>
> 5113. "Committed offsets can be stored in a local file to avoid reading
>
> the
>
> messages again when a broker is restarted." Could you describe the format
> and the location of the file? Also, could the same message be processed
>
> by
>
> RLMM again after broker restart? If so, how do we handle that?
>
> 5114. Message format
> 5114.1 There are two records named RemoteLogSegmentMetadataRecord with
> apiKey 0 and 1.
> 5114.2 RemoteLogSegmentMetadataRecord: Could we document whether
>
> endOffset
>
> is inclusive/exclusive?
> 5114.3 RemoteLogSegmentMetadataRecord: Could you explain LeaderEpoch a
>
> bit
>
> more? Is that the epoch of the leader when it copies the segment to
>
> remote
>
> storage? Also, how will this field be used?
> 5114.4 EventTimestamp: Could you explain this a bit more? Each record in
> Kafka already has a timestamp field. Could we just use that? 5114.5
> SegmentSizeInBytes: Could this just be int32?
>
> 5115. RemoteLogCleaner(RLC): This could be confused with the log cleaner
> for compaction. Perhaps it can be renamed to sth like
> RemotePartitionRemover.
>
> 5116. "RLC receives the delete_partition_marked and processes it if it is
> not yet processed earlier." How does it know whether
> delete_partition_marked has been processed earlier?
>
> 5117. Should we add a new MessageFormatter to read the tier metadata
>
> topic?
>
> 5118. "Maximum remote log reader thread pool task queue size. If the task
> queue is full, broker will stop reading remote log segments." What do we
> return to the fetch request in this case?
>
> 5119. It would be useful to list all things not supported in the first
> version in a Future work or Limitations section. For example, compacted
> topic, JBOD, changing remote.log.storage.enable from true to false, etc.
>
> Thanks,
>
> Jun
>
> On Tue, Oct 27, 2020 at 5:57 PM Kowshik Prakasam <kprakasam@confluent.io
>
> wrote:
>
> Hi Satish,
>
> Thanks for the updates to the KIP. Here are my first batch of
> comments/suggestions on the latest version of the KIP.
>
> 5012. In the RemoteStorageManager interface, there is an API defined
>
> for
>
> each file type. For example, fetchOffsetIndex, fetchTimestampIndex
>
> etc. To
>
> avoid the duplication, I'd suggest we can instead have a FileType enum
>
> and
>
> a common get API based on the FileType.
>
> 5013. There are some references to the Google doc in the KIP. I wasn't
>
> sure
>
> if the Google doc is expected to be in sync with the contents of the
>
> wiki.
>
> Going forward, it seems easier if just the KIP is maintained as the
>
> source
>
> of truth. In this regard, could you please move all the references to
>
> the
>
> Google doc, maybe to a separate References section at the bottom of the
> KIP?
>
> 5014. There are some TODO sections in the KIP. Would these be filled
>
> up in
>
> future iterations?
>
> 5015. Under "Topic deletion lifecycle", I'm trying to understand why
>
> do we
>
> need delete_partition_marked as well as the delete_partition_started
> messages. I couldn't spot a drawback if supposing we simplified the
>
> design
>
> such that the controller would only write delete_partition_started
>
> message,
>
> and RemoteLogCleaner (RLC) instance picks it up for processing. What
>
> am I
>
> missing?
>
> 5016. Under "Topic deletion lifecycle", step (4) is mentioned as "RLC
>
> gets
>
> all the remote log segments for the partition and each of these remote
>
> log
>
> segments is deleted with the next steps.". Since the RLC instance runs
>
> on
>
> each tier topic partition leader, how does the RLC then get the list of
> remote log segments to be deleted? It will be useful to add that
>
> detail to
>
> the KIP.
>
> 5017. Under "Public Interfaces -> Configs", there is a line mentioning
>
> "We
>
> will support flipping remote.log.storage.enable in next versions." It
>
> will
>
> be useful to mention this in the "Future Work" section of the KIP too.
>
> 5018. The KIP introduces a number of configuration parameters. It will
>
> be
>
> useful to mention in the KIP if the user should assume these as static
> configuration in the server.properties file, or dynamic configuration
>
> which
>
> can be modified without restarting the broker.
>
> 5019. Maybe this is planned as a future update to the KIP, but I
>
> thought
>
> I'd mention it here. Could you please add details to the KIP on why
>
> RocksDB
>
> was chosen as the default cache implementation of RLMM, and how it is
>
> going
>
> to be used? Were alternatives compared/considered? For example, it
>
> would be
>
> useful to explain/evaluate the following: 1) debuggability of the
>
> RocksDB
>
> JNI interface, 2) performance, 3) portability across platforms and 4)
> interface parity of RocksDB’s JNI api with it's underlying C/C++ api.
>
> 5020. Following up on (5019), for the RocksDB cache, it will be useful
>
> to
>
> explain the relationship/mapping between the following in the KIP: 1)
>
> # of
>
> tiered partitions, 2) # of partitions of metadata topic
> __remote_log_metadata and 3) # of RocksDB instances. i.e. is the plan
>
> to
>
> have a RocksDB instance per tiered partition, or per metadata topic
> partition, or just 1 for per broker?
>
> 5021. I was looking at the implementation prototype (PR link: https://
> github.com/apache/kafka/pull/7561). It seems that a boolean attribute is
> being introduced into the Log layer to check if remote log capability is
> enabled. While the boolean footprint is small at the
>
> moment,
>
> this can easily grow in the future and become harder to test/maintain,
> considering that the Log layer is already pretty
>
> complex. We
>
> should start thinking about how to manage such changes to the Log layer
> (for the purpose of improved testability, better separation of
>
> concerns and
>
> readability). One proposal I have is to take a step back and define a
> higher level Log interface. Then, the Broker code can be changed to use
> this interface. It can be changed such that only a handle to the
>
> interface
>
> is exposed to other components (such as LogCleaner, ReplicaManager
>
> etc.)
>
> and not the underlying Log object. This approach keeps the user of the
>
> Log
>
> layer agnostic of the whereabouts of the data. Underneath the
>
> interface,
>
> the implementing classes can completely separate local log capabilities
> from the remote log. For example, the Log class can be simplified to
>
> only
>
> manage logic surrounding local log segments and metadata.
>
> Additionally, a
>
> wrapper class can be provided (implementing the higher level Log
>
> interface)
>
> which will contain any/all logic surrounding tiered data. The wrapper
> class will wrap around an instance of the Log class delegating the
>
> local
>
> log logic to it. Finally, a handle to the wrapper class can be exposed
>
> to
>
> the other components wherever they need a handle to the higher level
>
> Log
>
> interface.
>
> Cheers,
> Kowshik
>
> On Mon, Oct 26, 2020 at 9:52 PM Satish Duggana <
>
> satish.duggana@gmail.com>
>
> wrote:
>
> Hi,
> KIP is updated with 1) topic deletion lifecycle and its related items
> 2) Protocol changes(mainly related to ListOffsets) and other minor
> changes.
> Please go through them and let us know your comments.
>
> Thanks,
> Satish.
>
> On Mon, Sep 28, 2020 at 9:10 PM Satish Duggana <
>
> satish.duggana@gmail.com
>
> wrote:
>
> Hi Dhruvil,
> Thanks for looking into the KIP and sending your comments. Sorry
>
> for
>
> the late reply, missed it in the mail thread.
>
> 1. Could you describe how retention would work with this KIP and
>
> which
>
> threads are responsible for driving this work? I believe there are
>
> 3
>
> kinds
>
> of retention processes we are looking at:
> (a) Regular retention for data in tiered storage as per
>
> configured `
>
> retention.ms` / `retention.bytes`.
> (b) Local retention for data in local storage as per configured ` local.
> log.retention.ms` / `local.log.retention.bytes`
> (c) Possibly regular retention for data in local storage, if the
>
> tiering
>
> task is lagging or for data that is below the log start offset.
>
> Local log retention is done by the existing log cleanup tasks.
>
> These
>
> are not done for segments that are not yet copied to remote
>
> storage.
>
> Remote log cleanup is done by the leader partition’s RLMTask.
>
> 2. When does a segment become eligible to be tiered? Is it as soon
>
> as
>
> the
>
> segment is rolled and the end offset is less than the last stable
>
> offset
>
> as
>
> mentioned in the KIP? I wonder if we need to consider other
>
> parameters
>
> too,
>
> like the highwatermark so that we are guaranteed that what we are
>
> tiering
>
> has been committed to the log and accepted by the ISR.
>
> AFAIK, last stable offset is always <= highwatermark. This will
>
> make
>
> sure we are always tiering the message segments which have been accepted
> by ISR and transactionally completed.
>
> 3. The section on "Follower Fetch Scenarios" is useful but is a bit
> difficult to parse at the moment. It would be useful to summarize
>
> the
>
> changes we need in the ReplicaFetcher.
>
> It may become difficult for users to read/follow if we add code
>
> changes
>
> here.
>
> 4. Related to the above, it's a bit unclear how we are planning on
> restoring the producer state for a new replica. Could you expand on
>
> that?
>
> It is mentioned in the KIP BuildingRemoteLogAuxState is introduced
>
> to
>
> build the state like leader epoch sequence and producer snapshots before
> it starts fetching the data from the leader. We will make it clear in the
> KIP.
>
> 5. Similarly, it would be worth summarizing the behavior on unclean
>
> leader
>
> election. There are several scenarios to consider here: data loss
>
> from
>
> local log, data loss from remote log, data loss from metadata
>
> topic,
>
> etc.
>
> It's worth describing these in detail.
>
> We mentioned the cases about unclean leader election in the
>
> follower
>
> fetch scenarios.
> If there are errors while fetching data from remote store or
>
> metadata
>
> store, it will work the same way as it works with local log. It returns
> the error back to the caller. Please let us know if I am missing your point
> here.
>
> 7. For a READ_COMMITTED FetchRequest, how do we retrieve and
>
> return the
>
> aborted transaction metadata?
>
> When a fetch for a remote log is accessed, we will fetch aborted
> transactions along with the segment if it is not found in the local index
> cache. This includes the case of transaction index not
>
> existing
>
> in the remote log segment. That means, the cache entry can be
>
> empty or
>
> have a list of aborted transactions.
>
> 8. The `LogSegmentData` class assumes that we have a log segment,
>
> offset
>
> index, time index, transaction index, producer snapshot and leader
>
> epoch
>
> index. How do we deal with cases where we do not have one or more
>
> of
>
> these?
>
> For example, we may not have a transaction index or producer
>
> snapshot
>
> for a
>
> particular segment. The former is optional, and the latter is only
>
> kept
>
> for
>
> up to the 3 latest segments.
>
> This is a good point, we discussed this in the last meeting. Transaction
> index is optional and we will copy them only if it
>
> exists.
>
> We want to keep all the producer snapshots at each log segment
>
> rolling
>
> and they can be removed if the log copying is successful and it
>
> still
>
> maintains the existing latest 3 segments, We only delete the
>
> producer
>
> snapshots which have been copied to remote log segments on leader.
> Follower will keep the log segments beyond the segments which have
>
> not
>
> been copied to remote storage. We will update the KIP with these details.
>
> Thanks,
> Satish.
>
> On Thu, Sep 17, 2020 at 1:47 AM Dhruvil Shah <dhruvil@confluent.io
>
> wrote:
>
> Hi Satish, Harsha,
>
> Thanks for the KIP. Few questions below:
>
> 1. Could you describe how retention would work with this KIP and
>
> which
>
> threads are responsible for driving this work? I believe there
>
> are 3
>
> kinds
>
> of retention processes we are looking at:
> (a) Regular retention for data in tiered storage as per
>
> configured
>
> `
>
> retention.ms` / `retention.bytes`.
> (b) Local retention for data in local storage as per
>
> configured `
>
> local.log.retention.ms` / `local.log.retention.bytes`
> (c) Possibly regular retention for data in local storage, if
>
> the
>
> tiering
>
> task is lagging or for data that is below the log start offset.
>
> 2. When does a segment become eligible to be tiered? Is it as
>
> soon as
>
> the
>
> segment is rolled and the end offset is less than the last stable
>
> offset as
>
> mentioned in the KIP? I wonder if we need to consider other
>
> parameters
>
> too,
>
> like the highwatermark so that we are guaranteed that what we are
>
> tiering
>
> has been committed to the log and accepted by the ISR.
>
> 3. The section on "Follower Fetch Scenarios" is useful but is a
>
> bit
>
> difficult to parse at the moment. It would be useful to
>
> summarize the
>
> changes we need in the ReplicaFetcher.
>
> 4. Related to the above, it's a bit unclear how we are planning
>
> on
>
> restoring the producer state for a new replica. Could you expand
>
> on
>
> that?
>
> 5. Similarly, it would be worth summarizing the behavior on
>
> unclean
>
> leader
>
> election. There are several scenarios to consider here: data loss
>
> from
>
> local log, data loss from remote log, data loss from metadata
>
> topic,
>
> etc.
>
> It's worth describing these in detail.
>
> 6. It would be useful to add details about how we plan on using
>
> RocksDB in
>
> the default implementation of `RemoteLogMetadataManager`.
>
> 7. For a READ_COMMITTED FetchRequest, how do we retrieve and
>
> return
>
> the
>
> aborted transaction metadata?
>
> 8. The `LogSegmentData` class assumes that we have a log segment,
>
> offset
>
> index, time index, transaction index, producer snapshot and
>
> leader
>
> epoch
>
> index. How do we deal with cases where we do not have one or
>
> more of
>
> these?
>
> For example, we may not have a transaction index or producer
>
> snapshot
>
> for a
>
> particular segment. The former is optional, and the latter is
>
> only
>
> kept for
>
> up to the 3 latest segments.
>
> Thanks,
> Dhruvil
>
> On Mon, Sep 7, 2020 at 6:54 PM Harsha Ch <ha...@gmail.com>
>
> wrote:
>
> Hi All,
>
> We are all working through the last meeting feedback. I'll
>
> cancel
>
> the
>
> tomorrow 's meeting and we can meanwhile continue our
>
> discussion in
>
> mailing
>
> list. We can start the regular meeting from next week onwards.
>
> Thanks,
>
> Harsha
>
> On Fri, Sep 04, 2020 at 8:41 AM, Satish Duggana <
>
> satish.duggana@gmail.com
>
> wrote:
>
> Hi Jun,
> Thanks for your thorough review and comments. Please find the
>
> inline
>
> replies below.
>
> 600. The topic deletion logic needs more details.
> 600.1 The KIP mentions "The controller considers the topic
>
> partition is
>
> deleted only when it determines that there are no log
>
> segments
>
> for
>
> that
>
> topic partition by using RLMM". How is this done?
>
> It uses RLMM#listSegments() returns all the segments for the
>
> given
>
> topic
>
> partition.
>
> 600.2 "If the delete option is enabled then the leader will
>
> stop
>
> RLM task
>
> and stop processing and it sets all the remote log segment
>
> metadata of
>
> that partition with a delete marker and publishes them to
>
> RLMM."
>
> We
>
> discussed this earlier. When a topic is being deleted, there
>
> may
>
> not be a
>
> leader for the deleted partition.
>
> This is a good point. As suggested in the meeting, we will
>
> add a
>
> separate
>
> section for topic/partition deletion lifecycle and this
>
> scenario
>
> will be
>
> addressed.
>
> 601. Unclean leader election
> 601.1 Scenario 1: new empty follower
> After step 1, the follower restores up to offset 3. So why
>
> does
>
> it
>
> have
>
> LE-2 <https://issues.apache.org/jira/browse/LE-2> at offset
>
> 5?
>
> Nice catch. It was showing the leader epoch fetched from the
>
> remote
>
> storage. It should be shown with the truncated till offset 3.
>
> Updated the
>
> KIP.
>
> 601.2 senario 5: After Step 3, leader A has inconsistent data
>
> between its
>
> local and the tiered data. For example. offset 3 has msg 3
>
> LE-0
>
> <https://issues.apache.org/jira/browse/LE-0> locally,
>
> but msg 5 LE-1 <https://issues.apache.org/jira/browse/LE-1>
>
> in
>
> the remote store. While it's ok for the unclean leader
>
> to lose data, it should still return consistent data, whether
>
> it's
>
> from
>
> the local or the remote store.
>
> There is no inconsistency here as LE-0
>
> <https://issues.apache.org/jira/browse/LE-0> offsets are [0, 4] and
>
> LE-2
>
> <https://issues.apache.org/jira/browse/LE-2>:
>
> [5, ]. It will always get the right records for the given
>
> offset
>
> and
>
> leader epoch. In case of remote, RSM is invoked to get the
>
> remote
>
> log
>
> segment that contains the given offset with the leader epoch.
>
> 601.4 It seems that retention is based on
> listRemoteLogSegments(TopicPartition topicPartition, long
>
> leaderEpoch).
>
> When there is an unclean leader election, it's possible for
>
> the
>
> new
>
> leader
>
> to not to include certain epochs in its epoch cache. How are
>
> remote
>
> segments associated with those epochs being cleaned?
>
> That is a good point. This leader will also cleanup the
>
> epochs
>
> earlier to
>
> its start leader epoch and delete those segments. It gets the
>
> earliest
>
> epoch for a partition and starts deleting segments from that
>
> leader
>
> epoch.
>
> We need one more API in RLMM to get the earliest leader
>
> epoch.
>
> 601.5 The KIP discusses the handling of unclean leader
>
> elections
>
> for user
>
> topics. What about unclean leader elections on
> __remote_log_segment_metadata?
> This is the same as other system topics like
>
> consumer_offsets,
>
> __transaction_state topics. As discussed in the meeting, we
>
> will
>
> add the
>
> behavior of __remote_log_segment_metadata topic’s unclean
>
> leader
>
> truncation.
>
> 602. It would be useful to clarify the limitations in the
>
> initial
>
> release.
>
> The KIP mentions not supporting compacted topics. What about
>
> JBOD
>
> and
>
> changing the configuration of a topic from delete to compact
>
> after
>
> remote.
>
> log. storage. enable ( http://remote.log.storage.enable/ )
>
> is
>
> enabled?
>
> This was updated in the KIP earlier.
>
> 603. RLM leader tasks:
> 603.1"It checks for rolled over LogSegments (which have the
>
> last
>
> message
>
> offset less than last stable offset of that topic partition)
>
> and
>
> copies
>
> them along with their offset/time/transaction indexes and
>
> leader
>
> epoch
>
> cache to the remote tier." It needs to copy the producer
>
> snapshot
>
> too.
>
> Right. It copies producer snapshots too as mentioned in
>
> LogSegmentData.
>
> 603.2 "Local logs are not cleaned up till those segments are
>
> copied
>
> successfully to remote even though their retention time/size
>
> is
>
> reached"
>
> This seems weird. If the tiering stops because the remote
>
> store
>
> is
>
> not
>
> available, we don't want the local data to grow forever.
>
> It was clarified in the discussion that the comment was more
>
> about
>
> the
>
> local storage goes beyond the log.retention. The above
>
> statement
>
> is about
>
> local.log.retention but not for the complete log.retention.
>
> When
>
> it
>
> reaches the log.retention then it will delete the local logs
>
> even
>
> though
>
> those are not copied to remote storage.
>
> 604. "RLM maintains a bounded cache(possibly LRU) of the
>
> index
>
> files of
>
> remote log segments to avoid multiple index fetches from the
>
> remote
>
> storage. These indexes can be used in the same way as local
>
> segment
>
> indexes are used." Could you provide more details on this?
>
> Are
>
> the
>
> indexes
>
> cached in memory or on disk? If on disk, where are they
>
> stored?
>
> Are the
>
> cached indexes bound by a certain size?
>
> These are cached on disk and stored in log.dir with a name
> “__remote_log_index_cache”. They are bound by the total size.
>
> This
>
> will
>
> be
>
> exposed as a user configuration,
>
> 605. BuildingRemoteLogAux
> 605.1 In this section, two options are listed. Which one is
>
> chosen?
>
> Option-2, updated the KIP.
>
> 605.2 In option 2, it says "Build the local leader epoch
>
> cache by
>
> cutting
>
> the leader epoch sequence received from remote storage to
>
> [LSO,
>
> ELO].
>
> (LSO
>
> = log start offset)." We need to do the same thing for the
>
> producer
>
> snapshot. However, it's hard to cut the producer snapshot to
>
> an
>
> earlier
>
> offset. Another option is to simply take the lastOffset from
>
> the
>
> remote
>
> segment and use that as the starting fetch offset in the
>
> follower.
>
> This
>
> avoids the need for cutting.
>
> Right, this was mentioned in the “transactional support”
>
> section
>
> about
>
> adding these details.
>
> 606. ListOffsets: Since we need a version bump, could you
>
> document
>
> it
>
> under a protocol change section?
>
> Sure, we will update the KIP.
>
> 607. "LogStartOffset of a topic can point to either of local
>
> segment or
>
> remote segment but it is initialised and maintained in the
>
> Log
>
> class like
>
> now. This is already maintained in `Log` class while loading
>
> the
>
> logs and
>
> it can also be fetched from RemoteLogMetadataManager." What
>
> will
>
> happen
>
> to
>
> the existing logic (e.g. log recovery) that currently
>
> depends on
>
> logStartOffset but assumes it's local?
>
> They use a field called localLogStartOffset which is the
>
> local
>
> log
>
> start
>
> offset..
>
> 608. Handle expired remote segment: How does it pick up new
>
> logStartOffset
>
> from deleteRecords?
>
> Good point. This was not addressed in the KIP. Will update
>
> the
>
> KIP
>
> on how
>
> the RLM task handles this scenario.
>
> 609. RLMM message format:
> 609.1 It includes both MaxTimestamp and EventTimestamp. Where
>
> does
>
> it get
>
> both since the message in the log only contains one
>
> timestamp?
>
> `EventTimeStamp` is the timestamp at which that segment
>
> metadata
>
> event is
>
> generated. This is more for audits.
>
> 609.2 If we change just the state (e.g. to DELETE_STARTED),
>
> it
>
> seems it's
>
> wasteful to have to include all other fields not changed.
>
> This is a good point. We thought about incremental updates.
>
> But
>
> we
>
> want
>
> to
>
> make sure all the events are in the expected order and take
>
> action
>
> based
>
> on the latest event. Will think through the approaches in
>
> detail
>
> and
>
> update here.
>
> 609.3 Could you document which process makes the following
>
> transitions
>
> DELETE_MARKED, DELETE_STARTED, DELETE_FINISHED?
>
> Okay, will document more details.
>
> 610. remote.log.reader.max.pending.tasks: "Maximum remote log
>
> reader
>
> thread pool task queue size. If the task queue is full,
>
> broker
>
> will stop
>
> reading remote log segments." What does the broker do if the
>
> queue
>
> is
>
> full?
>
> It returns an error for this topic partition.
>
> 611. What do we return if the request offset/epoch doesn't
>
> exist
>
> in the
>
> following API?
> RemoteLogSegmentMetadata
>
> remoteLogSegmentMetadata(TopicPartition
>
> topicPartition, long offset, int epochForOffset)
>
> This returns null. But we prefer to update the return type as
>
> Optional
>
> and
>
> return Empty if that does not exist.
>
> Thanks,
> Satish.
>
> On Tue, Sep 1, 2020 at 9:45 AM Jun Rao < jun@ confluent. io
>
> (
>
> jun@confluent.io ) > wrote:
>
> Hi, Satish,
>
> Thanks for the updated KIP. Made another pass. A few more
>
> comments
>
> below.
>
> 600. The topic deletion logic needs more details.
> 600.1 The KIP mentions "The controller considers the topic
>
> partition is
>
> deleted only when it determines that there are no log
>
> segments
>
> for that
>
> topic partition by using RLMM". How is this done? 600.2 "If
>
> the
>
> delete
>
> option is enabled then the leader will stop RLM task and
>
> stop
>
> processing
>
> and it sets all the remote log segment metadata of that
>
> partition
>
> with a
>
> delete marker and publishes them to RLMM." We discussed this
>
> earlier.
>
> When
>
> a topic is being deleted, there may not be a leader for the
>
> deleted
>
> partition.
>
> 601. Unclean leader election
> 601.1 Scenario 1: new empty follower
> After step 1, the follower restores up to offset 3. So why
>
> does
>
> it have
>
> LE-2 <https://issues.apache.org/jira/browse/LE-2> at
>
> offset 5?
>
> 601.2 senario 5: After Step 3, leader A has inconsistent
>
> data
>
> between
>
> its
>
> local and the tiered data. For example. offset 3 has msg 3
>
> LE-0
>
> <https://issues.apache.org/jira/browse/LE-0> locally,
>
> but msg 5 LE-1 <https://issues.apache.org/jira/browse/LE-1>
>
> in
>
> the remote store. While it's ok for the unclean leader
>
> to lose data, it should still return consistent data,
>
> whether
>
> it's from
>
> the local or the remote store.
> 601.3 The follower picks up log start offset using the
>
> following
>
> api.
>
> Suppose that we have 3 remote segments (LE,
>
> SegmentStartOffset)
>
> as (2,
>
> 10),
> (3, 20) and (7, 15) due to an unclean leader election.
>
> Using the
>
> following
>
> api will cause logStartOffset to go backward from 20 to 15.
>
> How
>
> do we
>
> prevent that?
> earliestLogOffset(TopicPartition topicPartition, int
>
> leaderEpoch)
>
> 601.4
>
> It
>
> seems that retention is based on
> listRemoteLogSegments(TopicPartition topicPartition, long
>
> leaderEpoch).
>
> When there is an unclean leader election, it's possible for
>
> the
>
> new
>
> leader
>
> to not to include certain epochs in its epoch cache. How are
>
> remote
>
> segments associated with those epochs being cleaned? 601.5
>
> The
>
> KIP
>
> discusses the handling of unclean leader elections for user
>
> topics. What
>
> about unclean leader elections on
> __remote_log_segment_metadata?
>
> 602. It would be useful to clarify the limitations in the
>
> initial
>
> release.
>
> The KIP mentions not supporting compacted topics. What about
>
> JBOD
>
> and
>
> changing the configuration of a topic from delete to compact
>
> after
>
> remote.
>
> log. storage. enable ( http://remote.log.storage.enable/ )
>
> is
>
> enabled?
>
> 603. RLM leader tasks:
> 603.1"It checks for rolled over LogSegments (which have the
>
> last
>
> message
>
> offset less than last stable offset of that topic
>
> partition) and
>
> copies
>
> them along with their offset/time/transaction indexes and
>
> leader
>
> epoch
>
> cache to the remote tier." It needs to copy the producer
>
> snapshot
>
> too.
>
> 603.2 "Local logs are not cleaned up till those segments are
>
> copied
>
> successfully to remote even though their retention
>
> time/size is
>
> reached"
>
> This seems weird. If the tiering stops because the remote
>
> store
>
> is not
>
> available, we don't want the local data to grow forever.
>
> 604. "RLM maintains a bounded cache(possibly LRU) of the
>
> index
>
> files of
>
> remote log segments to avoid multiple index fetches from the
>
> remote
>
> storage. These indexes can be used in the same way as local
>
> segment
>
> indexes are used." Could you provide more details on this?
>
> Are
>
> the
>
> indexes
>
> cached in memory or on disk? If on disk, where are they
>
> stored?
>
> Are the
>
> cached indexes bound by a certain size?
>
> 605. BuildingRemoteLogAux
> 605.1 In this section, two options are listed. Which one is
>
> chosen?
>
> 605.2
>
> In option 2, it says "Build the local leader epoch cache by
>
> cutting the
>
> leader epoch sequence received from remote storage to [LSO,
>
> ELO].
>
> (LSO
>
> = log start offset)." We need to do the same thing for the
>
> producer
>
> snapshot. However, it's hard to cut the producer snapshot
>
> to an
>
> earlier
>
> offset. Another option is to simply take the lastOffset
>
> from the
>
> remote
>
> segment and use that as the starting fetch offset in the
>
> follower. This
>
> avoids the need for cutting.
>
> 606. ListOffsets: Since we need a version bump, could you
>
> document it
>
> under a protocol change section?
>
> 607. "LogStartOffset of a topic can point to either of local
>
> segment or
>
> remote segment but it is initialised and maintained in the
>
> Log
>
> class
>
> like
>
> now. This is already maintained in `Log` class while
>
> loading the
>
> logs
>
> and
>
> it can also be fetched from RemoteLogMetadataManager." What
>
> will
>
> happen
>
> to
>
> the existing logic (e.g. log recovery) that currently
>
> depends on
>
> logStartOffset but assumes it's local?
>
> 608. Handle expired remote segment: How does it pick up new
>
> logStartOffset
>
> from deleteRecords?
>
> 609. RLMM message format:
> 609.1 It includes both MaxTimestamp and EventTimestamp.
>
> Where
>
> does it
>
> get
>
> both since the message in the log only contains one
>
> timestamp?
>
> 609.2 If
>
> we
>
> change just the state (e.g. to DELETE_STARTED), it seems
>
> it's
>
> wasteful
>
> to
>
> have to include all other fields not changed. 609.3 Could
>
> you
>
> document
>
> which process makes the following transitions DELETE_MARKED,
> DELETE_STARTED, DELETE_FINISHED?
>
> 610. remote.log.reader.max.pending.tasks: "Maximum remote
>
> log
>
> reader
>
> thread pool task queue size. If the task queue is full,
>
> broker
>
> will stop
>
> reading remote log segments." What does the broker do if the
>
> queue is
>
> full?
>
> 611. What do we return if the request offset/epoch doesn't
>
> exist
>
> in the
>
> following API?
> RemoteLogSegmentMetadata
>
> remoteLogSegmentMetadata(TopicPartition
>
> topicPartition, long offset, int epochForOffset)
>
> Jun
>
> On Mon, Aug 31, 2020 at 11:19 AM Satish Duggana < satish.
>
> duggana@
>
> gmail. com
>
> ( satish.duggana@gmail.com ) > wrote:
>
> KIP is updated with
> - Remote log segment metadata topic message format/schema.
> - Added remote log segment metadata state transitions and
>
> explained how
>
> the deletion of segments is handled, including the case of
>
> partition
>
> deletions.
> - Added a few more limitations in the "Non goals" section.
>
> Thanks,
> Satish.
>
> On Thu, Aug 27, 2020 at 12:42 AM Harsha Ch < harsha. ch@
>
> gmail.
>
> com (
>
> harsha.ch@gmail.com ) > wrote:
>
> Updated the KIP with Meeting Notes section
>
> https:/ / cwiki. apache. org/ confluence/ display/ KAFKA/
>
> KIP-405 <https://issues.apache.org/jira/browse/KIP-405>
>
> %3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
>
> (
>
> https://cwiki.apache.org/confluence/display/KAFKA/
> KIP-405%3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
>
> )
>
> On Tue, Aug 25, 2020 at 1:03 PM Jun Rao < jun@
>
> confluent. io
>
> (
>
> jun@confluent.io ) > wrote:
>
> Hi, Harsha,
>
> Thanks for the summary. Could you add the summary and the
>
> recording
>
> link to
>
> the last section of
>
> https:/ / cwiki. apache. org/ confluence/ display/ KAFKA/
>
> Kafka+Improvement+Proposals
>
> (
>
> https://cwiki.apache.org/confluence/display/KAFKA/
> Kafka+Improvement+Proposals
>
> )
>
> ?
>
> Jun
>
> On Tue, Aug 25, 2020 at 11:12 AM Harsha Chintalapani <
>
> kafka@
>
> harsha. io (
>
> kafka@harsha.io ) > wrote:
>
> Thanks everyone for attending the meeting today.
> Here is the recording
>
> https:/ / drive. google. com/ file/ d/
>
> 14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/ view?usp=sharing
>
> (
>
> https://drive.google.com/file/d/14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/
> view?usp=sharing
>
> )
>
> Notes:
>
> 1. KIP is updated with follower fetch protocol and
>
> ready to
>
> reviewed
>
> 2. Satish to capture schema of internal metadata topic
>
> in
>
> the
>
> KIP
>
> 3. We will update the KIP with details of different
>
> cases
>
> 4. Test plan will be captured in a doc and will add to
>
> the
>
> KIP
>
> 5. Add a section "Limitations" to capture the
>
> capabilities
>
> that
>
> will
>
> be
>
> introduced with this KIP and what will not be covered in
>
> this
>
> KIP.
>
> Please add to it I missed anything. Will produce a
>
> formal
>
> meeting
>
> notes
>
> from next meeting onwards.
>
> Thanks,
> Harsha
>
> On Mon, Aug 24, 2020 at 9:42 PM, Ying Zheng < yingz@
>
> uber.
>
> com.
>
> invalid (
>
> yingz@uber.com.invalid ) > wrote:
>
> We did some basic feature tests at Uber. The test
>
> cases and
>
> results are
>
> shared in this google doc:
> https:/ / docs. google. com/ spreadsheets/ d/ (
> https://docs.google.com/spreadsheets/d/ )
>
> 1XhNJqjzwXvMCcAOhEH0sSXU6RTvyoSf93DHF-YMfGLk/edit?usp=sharing
>
> The performance test results were already shared in
>
> the KIP
>
> last
>
> month.
>
> On Mon, Aug 24, 2020 at 11:10 AM Harsha Ch < harsha.
>
> ch@
>
> gmail.
>
> com (
>
> harsha.ch@gmail.com ) >
>
> wrote:
>
> "Understand commitments towards driving design &
>
> implementation of
>
> the
>
> KIP
>
> further and how it aligns with participant interests in
>
> contributing to
>
> the
>
> efforts (ex: in the context of Uber’s Q3/Q4 roadmap)."
>
> What
>
> is that
>
> about?
>
> On Mon, Aug 24, 2020 at 11:05 AM Kowshik Prakasam <
>
> kprakasam@ confluent. io ( kprakasam@confluent.io ) >
>
> wrote:
>
> Hi Harsha,
>
> The following google doc contains a proposal for
>
> temporary
>
> agenda
>
> for
>
> the
>
> KIP-405 <https://issues.apache.org/jira/browse/KIP-405>
>
> <
>
> https:/ / issues. apache. org/ jira/ browse/ KIP-405
> <https://issues.apache.org/jira/browse/KIP-405> (
>
> https://issues.apache.org/jira/browse/KIP-405 ) > sync
>
> meeting
>
> tomorrow:
>
> https:/ / docs. google. com/ document/ d/ (
> https://docs.google.com/document/d/ )
> 1pqo8X5LU8TpwfC_iqSuVPezhfCfhGkbGN2TqiPA3LBU/edit
>
> .
> Please could you add it to the Google calendar invite?
>
> Thank you.
>
> Cheers,
> Kowshik
>
> On Thu, Aug 20, 2020 at 10:58 AM Harsha Ch < harsha.
>
> ch@
>
> gmail.
>
> com (
>
> harsha.ch@gmail.com ) >
>
> wrote:
>
> Hi All,
>
> Scheduled a meeting for Tuesday 9am - 10am. I can
>
> record
>
> and
>
> upload for
>
> community to be able to follow the discussion.
>
> Jun, please add the required folks on confluent side.
>
> Thanks,
>
> Harsha
>
> On Thu, Aug 20, 2020 at 12:33 AM, Alexandre Dupriez <
>
> alexandre.dupriez@
>
> gmail. com ( http://gmail.com/ ) > wrote:
>
> Hi Jun,
>
> Many thanks for your initiative.
>
> If you like, I am happy to attend at the time you
>
> suggested.
>
> Many thanks,
> Alexandre
>
> Le mer. 19 août 2020 à 22:00, Harsha Ch < harsha. ch@
>
> gmail. com (
>
> harsha.
>
> ch@ gmail. com ( ch@gmail.com ) ) > a écrit :
>
> Hi Jun,
> Thanks. This will help a lot. Tuesday will work for us.
> -Harsha
>
> On Wed, Aug 19, 2020 at 1:24 PM Jun Rao < jun@
>
> confluent.
>
> io (
>
> jun@
>
> confluent. io ( http://confluent.io/ ) ) > wrote:
>
> Hi, Satish, Ying, Harsha,
>
> Do you think it would be useful to have a regular
>
> virtual
>
> meeting
>
> to
>
> discuss this KIP? The goal of the meeting will be
>
> sharing
>
> design/development progress and discussing any open
>
> issues
>
> to
>
> accelerate
>
> this KIP. If so, will every Tuesday (from next week)
>
> 9am-10am
>
> PT
>
> work for you? I can help set up a Zoom meeting, invite
>
> everyone who
>
> might
>
> be interested, have it recorded and shared, etc.
>
> Thanks,
>
> Jun
>
> On Tue, Aug 18, 2020 at 11:01 AM Satish Duggana <
>
> satish. duggana@ gmail. com ( satish. duggana@ gmail.
>
> com
>
> (
>
> satish.duggana@gmail.com ) ) >
>
> wrote:
>
> Hi Kowshik,
>
> Thanks for looking into the KIP and sending your
>
> comments.
>
> 5001. Under the section "Follower fetch protocol in
>
> detail",
>
> the
>
> next-local-offset is the offset upto which the
>
> segments are
>
> copied
>
>

Re: [DISCUSS] KIP-405: Kafka Tiered Storage

[Kowshik Prakasam <kp...@confluent.io>]

Hi Harsha/Satish,

Thanks for the discussion today. Here is a link to the KIP-405 development
milestones google doc we discussed in the meeting today:
https://docs.google.com/document/d/1B5_jaZvWWb2DUpgbgImq0k_IPZ4DWrR8Ru7YpuJrXdc/edit
. I have shared it with you. Please have a look and share your
feedback/improvements. As we discussed, things are clear until milestone 1.
Beyond that, we can discuss it again (perhaps in next sync or later), once
you have thought through the implementation plan/milestones and release
into preview in 3.0.


Cheers,
Kowshik


On Tue, Nov 10, 2020 at 6:56 AM Satish Duggana <sa...@gmail.com>
wrote:

> Hi Jun,
> Thanks for your comments. Please find the inline replies below.
>
> 605.2 "Build the local leader epoch cache by cutting the leader epoch
> sequence received from remote storage to [LSO, ELO]." I mentioned an issue
> earlier. Suppose the leader's local start offset is 100. The follower finds
> a remote segment covering offset range [80, 120). The producerState with
> this remote segment is up to offset 120. To trim the producerState to
> offset 100 requires more work since one needs to download the previous
> producerState up to offset 80 and then replay the messages from 80 to 100.
> It seems that it's simpler in this case for the follower just to take the
> remote segment as it is and start fetching from offset 120.
>
> We chose that approach to avoid any edge cases here. It may be
> possible that the remote log segment that is received may not have the
> same leader epoch sequence from 100-120 as it contains on the
> leader(this can happen due to unclean leader). It is safe to start
> from what the leader returns here.Another way is to find the remote
> log segment
>
> 5016. Just to echo what Kowshik was saying. It seems that
> RLMM.onPartitionLeadershipChanges() is only called on the replicas for a
> partition, not on the replicas for the __remote_log_segment_metadata
> partition. It's not clear how the leader of __remote_log_segment_metadata
> obtains the metadata for remote segments for deletion.
>
> RLMM will always receive the callback for the remote log metadata
> topic partitions hosted on the local broker and these will be
> subscribed. I will make this clear in the KIP.
>
> 5100. KIP-516 has been accepted and is being implemented now. Could you
> update the KIP based on topicID?
>
> We mentioned KIP-516 and how it helps. We will update this KIP with
> all the changes it brings with KIP-516.
>
> 5101. RLMM: It would be useful to clarify how the following two APIs are
> used. According to the wiki, the former is used for topic deletion and the
> latter is used for retention. It seems that retention should use the former
> since remote segments without a matching epoch in the leader (potentially
> due to unclean leader election) also need to be garbage collected. The
> latter seems to be used for the new leader to determine the last tiered
> segment.
>     default Iterator<RemoteLogSegmentMetadata>
> listRemoteLogSegments(TopicPartition topicPartition)
>     Iterator<RemoteLogSegmentMetadata> listRemoteLogSegments(TopicPartition
> topicPartition, long leaderEpoch);
>
> Right,.that is what we are currently doing. We will update the
> javadocs and wiki with that. Earlier, we did not want to remove the
> segments which are not matched with leader epochs from the ladder
> partition as they may be used later by a replica which can become a
> leader (unclean leader election) and refer those segments. But that
> may leak these segments in remote storage until the topic lifetime. We
> decided to cleanup the segments with the oldest incase of size based
> retention also.
>
> 5102. RSM:
> 5102.1 For methods like fetchLogSegmentData(), it seems that they can
> use RemoteLogSegmentId instead of RemoteLogSegmentMetadata.
>
> It will be useful to have metadata for RSM to fetch log segment. It
> may create location/path using id with other metadata too.
>
> 5102.2 In fetchLogSegmentData(), should we use long instead of Long?
>
> Wanted to keep endPosition as optional to read till the end of the
> segment and avoid sentinels.
>
> 5102.3 Why only some of the methods have default implementation and others
> Don't?
>
> Actually,  RSM will not have any default implementations. Those 3
> methods were made default earlier for tests etc. Updated the wiki.
>
> 5102.4. Could we define RemoteLogSegmentMetadataUpdate
> and DeletePartitionUpdate?
>
> Sure, they will be added.
>
>
> 5102.5 LogSegmentData: It seems that it's easier to pass
> in leaderEpochIndex as a ByteBuffer or byte array than a file since it will
> be generated in memory.
>
> Right, this is in plan.
>
> 5102.6 RemoteLogSegmentMetadata: It seems that it needs both baseOffset and
> startOffset. For example, deleteRecords() could move the startOffset to the
> middle of a segment. If we copy the full segment to remote storage, the
> baseOffset and the startOffset will be different.
>
> Good point. startOffset is baseOffset by default, if not set explicitly.
>
> 5102.7 Could we define all the public methods for RemoteLogSegmentMetadata
> and LogSegmentData?
>
> Sure, updated the wiki.
>
> 5102.8 Could we document whether endOffset in RemoteLogSegmentMetadata is
> inclusive/exclusive?
>
> It is inclusive, will update.
>
> 5103. configs:
> 5103.1 Could we define the default value of non-required configs (e.g the
> size of new thread pools)?
>
> Sure, that makes sense.
>
> 5103.2 It seems that local.log.retention.ms should default to retention.ms
> ,
> instead of remote.log.retention.minutes. Similarly, it seems
> that local.log.retention.bytes should default to segment.bytes.
>
> Right, we do not have  remote.log.retention as we discussed earlier.
> Thanks for catching the typo.
>
> 5103.3 remote.log.manager.thread.pool.size: The description says "used in
> scheduling tasks to copy segments, fetch remote log indexes and clean up
> remote log segments". However, there is a separate
> config remote.log.reader.threads for fetching remote data. It's weird to
> fetch remote index and log in different thread pools since both are used
> for serving fetch requests.
>
> Right, remote.log.manager.thread.pool is mainly used for copy/cleanup
> activities. Fetch path always goes through remote.log.reader.threads.
>
> 5103.4 remote.log.manager.task.interval.ms: Is that the amount of time to
> back off when there is no work to do? If so, perhaps it can be renamed as
> backoff.ms.
>
> This is the delay interval for each iteration. It may be renamed to
> remote.log.manager.task.delay.ms
>
> 5103.5 Are rlm_process_interval_ms and rlm_retry_interval_ms configs? If
> so, they need to be listed in this section.
>
> remote.log.manager.task.interval.ms is the process internal, retry
> interval is missing in the configs, which will be updated in the KIP.
>
> 5104. "RLM maintains a bounded cache(possibly LRU) of the index files of
> remote log segments to avoid multiple index fetches from the remote
> storage." Is the RLM in memory or on disk? If on disk, where is it stored?
> Do we need a configuration to bound the size?
>
> It is stored on disk. They are stored in a directory
> `remote-log-index-cache` under log dir. We plan to have a config for
> that instead of default. We will have a configuration for that.
>
> 5105. The KIP uses local-log-start-offset and Earliest Local Offset in
> different places. It would be useful to standardize the terminology.
>
> Sure.
>
> 5106. The section on "In BuildingRemoteLogAux state". It listed two options
> without saying which option is chosen.
> We already mentioned in the KIP that we chose option-2.
>
> 5107. Follower to leader transition: It has step 2, but not step 1.
> Step-1 is there but it is not explicitly highlighted. It is previous
> table to step-2.
>
> 5108. If a consumer fetches from the remote data and the remote storage is
> not available, what error code is used in the fetch response?
>
> Good point. We have not yet defined the error for this case. We need
> to define an error message and send the same in fetch response.
>
> 5109. "ListOffsets: For timestamps >= 0, it returns the first message
> offset whose timestamp is >= to the given timestamp in the request. That
> means it checks in remote log time indexes first, after which local log
> time indexes are checked." Could you document which method in RLMM is used
> for this?
>
> Okay.
>
> 5110. Stopreplica: "it sets all the remote log segment metadata of that
> partition with a delete marker and publishes them to RLMM." This seems
> outdated given the new topic deletion logic.
>
> Will update with KIP-516 related points.
>
> 5111. "RLM follower fetches the earliest offset for the earliest leader
> epoch by calling RLMM.earliestLogOffset(TopicPartition topicPartition, int
> leaderEpoch) and updates that as the log start offset." Do we need that
> since replication propagates logStartOffset already?
>
> Good point. Right, existing replication protocol takes care of
> updating the followers’s log start offset received from the leader.
>
> 5112. Is the default maxWaitMs of 500ms enough for fetching from remote
> storage?
>
> Remote reads may fail within the current default wait time, but
> subsequent fetches would be able to serve as that data is stored in
> the local cache. This cache is currently implemented in RSMs. But we
> plan to pull this into the remote log messaging layer in future.
>
> 5113. "Committed offsets can be stored in a local file to avoid reading the
> messages again when a broker is restarted." Could you describe the format
> and the location of the file? Also, could the same message be processed by
> RLMM again after broker restart? If so, how do we handle that?
>
> Sure, we will update in the KIP.
>
> 5114. Message format
> 5114.1 There are two records named RemoteLogSegmentMetadataRecord with
> apiKey 0 and 1.
>
> Nice catch, that was a typo. Fixed in the wiki.
>
> 5114.2 RemoteLogSegmentMetadataRecord: Could we document whether endOffset
> is inclusive/exclusive?
> It is inclusive, will update.
>
> 5114.3 RemoteLogSegmentMetadataRecord: Could you explain LeaderEpoch a bit
> more? Is that the epoch of the leader when it copies the segment to remote
> storage? Also, how will this field be used?
>
> Right, this is the leader epoch of the broker which copied this
> segment. This is helpful in reason about which broker copied the
> segment to remote storage.
>
> 5114.4 EventTimestamp: Could you explain this a bit more? Each record in
> Kafka already has a timestamp field. Could we just use that?
>
> This is the  timestamp at which  the respective event occurred. Added
> this  to RemoteLogSegmentMetadata as RLMM can be  any other
> implementation. We thought about that but it looked cleaner to use at
> the message structure level instead of getting that from the consumer
> record and using that to build the respective event.
>
>
> 5114.5 SegmentSizeInBytes: Could this just be int32?
>
> Right, it looks like config allows only int value >= 14.
>
> 5115. RemoteLogCleaner(RLC): This could be confused with the log cleaner
> for compaction. Perhaps it can be renamed to sth like
> RemotePartitionRemover.
>
> I am fine with RemotePartitionRemover or RemoteLogDeletionManager(we
> have other manager classes like RLM, RLMM).
>
> 5116. "RLC receives the delete_partition_marked and processes it if it is
> not yet processed earlier." How does it know whether
> delete_partition_marked has been processed earlier?
>
> This is to handle duplicate delete_partition_marked events. RLC
> internally maintains a state for the delete_partition events and if it
> already has an existing event then it ignores if it is already being
> processed.
>
> 5117. Should we add a new MessageFormatter to read the tier metadata topic?
>
> Right, this is in plan but did not mention it in the KIP. This will be
> useful for debugging purposes too.
>
> 5118. "Maximum remote log reader thread pool task queue size. If the task
> queue is full, broker will stop reading remote log segments." What do we
> return to the fetch request in this case?
>
> We return an error response for that partition.
>
> 5119. It would be useful to list all things not supported in the first
> version in a Future work or Limitations section. For example, compacted
> topic, JBOD, changing remote.log.storage.enable from true to false, etc.
>
> We already have a non-goals section which is filled with some of these
> details. Do we need another limitations section?
>
> Thanks,
> Satish.
>
> On Wed, Nov 4, 2020 at 11:27 PM Jun Rao <ju...@confluent.io> wrote:
> >
> > Hi, Satish,
> >
> > Thanks for the updated KIP. A few more comments below.
> >
> > 605.2 "Build the local leader epoch cache by cutting the leader epoch
> > sequence received from remote storage to [LSO, ELO]." I mentioned an
> issue
> > earlier. Suppose the leader's local start offset is 100. The follower
> finds
> > a remote segment covering offset range [80, 120). The producerState with
> > this remote segment is up to offset 120. To trim the producerState to
> > offset 100 requires more work since one needs to download the previous
> > producerState up to offset 80 and then replay the messages from 80 to
> 100.
> > It seems that it's simpler in this case for the follower just to take the
> > remote segment as it is and start fetching from offset 120.
> >
> > 5016. Just to echo what Kowshik was saying. It seems that
> > RLMM.onPartitionLeadershipChanges() is only called on the replicas for a
> > partition, not on the replicas for the __remote_log_segment_metadata
> > partition. It's not clear how the leader of __remote_log_segment_metadata
> > obtains the metadata for remote segments for deletion.
> >
> > 5100. KIP-516 has been accepted and is being implemented now. Could you
> > update the KIP based on topicID?
> >
> > 5101. RLMM: It would be useful to clarify how the following two APIs are
> > used. According to the wiki, the former is used for topic deletion and
> the
> > latter is used for retention. It seems that retention should use the
> former
> > since remote segments without a matching epoch in the leader (potentially
> > due to unclean leader election) also need to be garbage collected. The
> > latter seems to be used for the new leader to determine the last tiered
> > segment.
> >     default Iterator<RemoteLogSegmentMetadata>
> > listRemoteLogSegments(TopicPartition topicPartition)
> >     Iterator<RemoteLogSegmentMetadata>
> listRemoteLogSegments(TopicPartition
> > topicPartition, long leaderEpoch);
> >
> > 5102. RSM:
> > 5102.1 For methods like fetchLogSegmentData(), it seems that they can
> > use RemoteLogSegmentId instead of RemoteLogSegmentMetadata.
> > 5102.2 In fetchLogSegmentData(), should we use long instead of Long?
> > 5102.3 Why only some of the methods have default implementation and
> others
> > don't?
> > 5102.4. Could we define RemoteLogSegmentMetadataUpdate
> > and DeletePartitionUpdate?
> > 5102.5 LogSegmentData: It seems that it's easier to pass
> > in leaderEpochIndex as a ByteBuffer or byte array than a file since it
> will
> > be generated in memory.
> > 5102.6 RemoteLogSegmentMetadata: It seems that it needs both baseOffset
> and
> > startOffset. For example, deleteRecords() could move the startOffset to
> the
> > middle of a segment. If we copy the full segment to remote storage, the
> > baseOffset and the startOffset will be different.
> > 5102.7 Could we define all the public methods for
> RemoteLogSegmentMetadata
> > and LogSegmentData?
> > 5102.8 Could we document whether endOffset in RemoteLogSegmentMetadata is
> > inclusive/exclusive?
> >
> > 5103. configs:
> > 5103.1 Could we define the default value of non-required configs (e.g the
> > size of new thread pools)?
> > 5103.2 It seems that local.log.retention.ms should default to
> retention.ms,
> > instead of remote.log.retention.minutes. Similarly, it seems
> > that local.log.retention.bytes should default to segment.bytes.
> > 5103.3 remote.log.manager.thread.pool.size: The description says "used in
> > scheduling tasks to copy segments, fetch remote log indexes and clean up
> > remote log segments". However, there is a separate
> > config remote.log.reader.threads for fetching remote data. It's weird to
> > fetch remote index and log in different thread pools since both are used
> > for serving fetch requests.
> > 5103.4 remote.log.manager.task.interval.ms: Is that the amount of time
> to
> > back off when there is no work to do? If so, perhaps it can be renamed as
> > backoff.ms.
> > 5103.5 Are rlm_process_interval_ms and rlm_retry_interval_ms configs? If
> > so, they need to be listed in this section.
> >
> > 5104. "RLM maintains a bounded cache(possibly LRU) of the index files of
> > remote log segments to avoid multiple index fetches from the remote
> > storage." Is the RLM in memory or on disk? If on disk, where is it
> stored?
> > Do we need a configuration to bound the size?
> >
> > 5105. The KIP uses local-log-start-offset and Earliest Local Offset in
> > different places. It would be useful to standardize the terminology.
> >
> > 5106. The section on "In BuildingRemoteLogAux state". It listed two
> options
> > without saying which option is chosen.
> >
> > 5107. Follower to leader transition: It has step 2, but not step 1.
> >
> > 5108. If a consumer fetches from the remote data and the remote storage
> is
> > not available, what error code is used in the fetch response?
> >
> > 5109. "ListOffsets: For timestamps >= 0, it returns the first message
> > offset whose timestamp is >= to the given timestamp in the request. That
> > means it checks in remote log time indexes first, after which local log
> > time indexes are checked." Could you document which method in RLMM is
> used
> > for this?
> >
> > 5110. Stopreplica: "it sets all the remote log segment metadata of that
> > partition with a delete marker and publishes them to RLMM." This seems
> > outdated given the new topic deletion logic.
> >
> > 5111. "RLM follower fetches the earliest offset for the earliest leader
> > epoch by calling RLMM.earliestLogOffset(TopicPartition topicPartition,
> int
> > leaderEpoch) and updates that as the log start offset." Do we need that
> > since replication propagates logStartOffset already?
> >
> > 5112. Is the default maxWaitMs of 500ms enough for fetching from remote
> > storage?
> >
> > 5113. "Committed offsets can be stored in a local file to avoid reading
> the
> > messages again when a broker is restarted." Could you describe the format
> > and the location of the file? Also, could the same message be processed
> by
> > RLMM again after broker restart? If so, how do we handle that?
> >
> > 5114. Message format
> > 5114.1 There are two records named RemoteLogSegmentMetadataRecord with
> > apiKey 0 and 1.
> > 5114.2 RemoteLogSegmentMetadataRecord: Could we document whether
> endOffset
> > is inclusive/exclusive?
> > 5114.3 RemoteLogSegmentMetadataRecord: Could you explain LeaderEpoch a
> bit
> > more? Is that the epoch of the leader when it copies the segment to
> remote
> > storage? Also, how will this field be used?
> > 5114.4 EventTimestamp: Could you explain this a bit more? Each record in
> > Kafka already has a timestamp field. Could we just use that?
> > 5114.5 SegmentSizeInBytes: Could this just be int32?
> >
> > 5115. RemoteLogCleaner(RLC): This could be confused with the log cleaner
> > for compaction. Perhaps it can be renamed to sth like
> > RemotePartitionRemover.
> >
> > 5116. "RLC receives the delete_partition_marked and processes it if it is
> > not yet processed earlier." How does it know whether
> > delete_partition_marked has been processed earlier?
> >
> > 5117. Should we add a new MessageFormatter to read the tier metadata
> topic?
> >
> > 5118. "Maximum remote log reader thread pool task queue size. If the task
> > queue is full, broker will stop reading remote log segments." What do we
> > return to the fetch request in this case?
> >
> > 5119. It would be useful to list all things not supported in the first
> > version in a Future work or Limitations section. For example, compacted
> > topic, JBOD, changing remote.log.storage.enable from true to false, etc.
> >
> > Thanks,
> >
> > Jun
> >
> > On Tue, Oct 27, 2020 at 5:57 PM Kowshik Prakasam <kprakasam@confluent.io
> >
> > wrote:
> >
> > > Hi Satish,
> > >
> > > Thanks for the updates to the KIP. Here are my first batch of
> > > comments/suggestions on the latest version of the KIP.
> > >
> > > 5012. In the RemoteStorageManager interface, there is an API defined
> for
> > > each file type. For example, fetchOffsetIndex, fetchTimestampIndex
> etc. To
> > > avoid the duplication, I'd suggest we can instead have a FileType enum
> and
> > > a common get API based on the FileType.
> > >
> > > 5013. There are some references to the Google doc in the KIP. I wasn't
> sure
> > > if the Google doc is expected to be in sync with the contents of the
> wiki.
> > > Going forward, it seems easier if just the KIP is maintained as the
> source
> > > of truth. In this regard, could you please move all the references to
> the
> > > Google doc, maybe to a separate References section at the bottom of the
> > > KIP?
> > >
> > > 5014. There are some TODO sections in the KIP. Would these be filled
> up in
> > > future iterations?
> > >
> > > 5015. Under "Topic deletion lifecycle", I'm trying to understand why
> do we
> > > need delete_partition_marked as well as the delete_partition_started
> > > messages. I couldn't spot a drawback if supposing we simplified the
> design
> > > such that the controller would only write delete_partition_started
> message,
> > > and RemoteLogCleaner (RLC) instance picks it up for processing. What
> am I
> > > missing?
> > >
> > > 5016. Under "Topic deletion lifecycle", step (4) is mentioned as "RLC
> gets
> > > all the remote log segments for the partition and each of these remote
> log
> > > segments is deleted with the next steps.". Since the RLC instance runs
> on
> > > each tier topic partition leader, how does the RLC then get the list of
> > > remote log segments to be deleted? It will be useful to add that
> detail to
> > > the KIP.
> > >
> > > 5017. Under "Public Interfaces -> Configs", there is a line mentioning
> "We
> > > will support flipping remote.log.storage.enable in next versions." It
> will
> > > be useful to mention this in the "Future Work" section of the KIP too.
> > >
> > > 5018. The KIP introduces a number of configuration parameters. It will
> be
> > > useful to mention in the KIP if the user should assume these as static
> > > configuration in the server.properties file, or dynamic configuration
> which
> > > can be modified without restarting the broker.
> > >
> > > 5019.  Maybe this is planned as a future update to the KIP, but I
> thought
> > > I'd mention it here. Could you please add details to the KIP on why
> RocksDB
> > > was chosen as the default cache implementation of RLMM, and how it is
> going
> > > to be used? Were alternatives compared/considered? For example, it
> would be
> > > useful to explain/evaluate the following: 1) debuggability of the
> RocksDB
> > > JNI interface, 2) performance, 3) portability across platforms and 4)
> > > interface parity of RocksDB’s JNI api with it's underlying C/C++ api.
> > >
> > > 5020. Following up on (5019), for the RocksDB cache, it will be useful
> to
> > > explain the relationship/mapping between the following in the KIP: 1)
> # of
> > > tiered partitions, 2) # of partitions of metadata topic
> > > __remote_log_metadata and 3) # of RocksDB instances. i.e. is the plan
> to
> > > have a RocksDB instance per tiered partition, or per metadata topic
> > > partition, or just 1 for per broker?
> > >
> > > 5021. I was looking at the implementation prototype (PR link:
> > > https://github.com/apache/kafka/pull/7561). It seems that a boolean
> > > attribute is being introduced into the Log layer to check if remote log
> > > capability is enabled. While the boolean footprint is small at the
> moment,
> > > this can easily grow in the future and become harder to
> > > test/maintain, considering that the Log layer is already pretty
> complex. We
> > > should start thinking about how to manage such changes to the Log layer
> > > (for the purpose of improved testability, better separation of
> concerns and
> > > readability). One proposal I have is to take a step back and define a
> > > higher level Log interface. Then, the Broker code can be changed to use
> > > this interface. It can be changed such that only a handle to the
> interface
> > > is exposed to other components (such as LogCleaner, ReplicaManager
> etc.)
> > > and not the underlying Log object. This approach keeps the user of the
> Log
> > > layer agnostic of the whereabouts of the data. Underneath the
> interface,
> > > the implementing classes can completely separate local log capabilities
> > > from the remote log. For example, the Log class can be simplified to
> only
> > > manage logic surrounding local log segments and metadata.
> Additionally, a
> > > wrapper class can be provided (implementing the higher level Log
> interface)
> > > which will contain any/all logic surrounding tiered data. The wrapper
> > > class will wrap around an instance of the Log class delegating the
> local
> > > log logic to it. Finally, a handle to the wrapper class can be exposed
> to
> > > the other components wherever they need a handle to the higher level
> Log
> > > interface.
> > >
> > >
> > > Cheers,
> > > Kowshik
> > >
> > > On Mon, Oct 26, 2020 at 9:52 PM Satish Duggana <
> satish.duggana@gmail.com>
> > > wrote:
> > >
> > > > Hi,
> > > > KIP is updated with 1) topic deletion lifecycle and its related items
> > > > 2) Protocol changes(mainly related to ListOffsets) and other minor
> > > > changes.
> > > > Please go through them and let us know your comments.
> > > >
> > > > Thanks,
> > > > Satish.
> > > >
> > > > On Mon, Sep 28, 2020 at 9:10 PM Satish Duggana <
> satish.duggana@gmail.com
> > > >
> > > > wrote:
> > > > >
> > > > > Hi Dhruvil,
> > > > > Thanks for looking into the KIP and sending your comments. Sorry
> for
> > > > > the late reply, missed it in the mail thread.
> > > > >
> > > > > 1. Could you describe how retention would work with this KIP and
> which
> > > > > threads are responsible for driving this work? I believe there are
> 3
> > > > kinds
> > > > > of retention processes we are looking at:
> > > > >   (a) Regular retention for data in tiered storage as per
> configured `
> > > > > retention.ms` / `retention.bytes`.
> > > > >   (b) Local retention for data in local storage as per configured `
> > > > > local.log.retention.ms` / `local.log.retention.bytes`
> > > > >   (c) Possibly regular retention for data in local storage, if the
> > > > tiering
> > > > > task is lagging or for data that is below the log start offset.
> > > > >
> > > > > Local log retention is done by the existing log cleanup tasks.
> These
> > > > > are not done for segments that are not yet copied to remote
> storage.
> > > > > Remote log cleanup is done by the leader partition’s RLMTask.
> > > > >
> > > > > 2. When does a segment become eligible to be tiered? Is it as soon
> as
> > > the
> > > > > segment is rolled and the end offset is less than the last stable
> > > offset
> > > > as
> > > > > mentioned in the KIP? I wonder if we need to consider other
> parameters
> > > > too,
> > > > > like the highwatermark so that we are guaranteed that what we are
> > > tiering
> > > > > has been committed to the log and accepted by the ISR.
> > > > >
> > > > > AFAIK, last stable offset is always <= highwatermark. This will
> make
> > > > > sure we are always tiering the message segments which have been
> > > > > accepted by ISR and transactionally completed.
> > > > >
> > > > >
> > > > > 3. The section on "Follower Fetch Scenarios" is useful but is a bit
> > > > > difficult to parse at the moment. It would be useful to summarize
> the
> > > > > changes we need in the ReplicaFetcher.
> > > > >
> > > > > It may become difficult for users to read/follow if we add code
> changes
> > > > here.
> > > > >
> > > > > 4. Related to the above, it's a bit unclear how we are planning on
> > > > > restoring the producer state for a new replica. Could you expand on
> > > that?
> > > > >
> > > > > It is mentioned in the KIP BuildingRemoteLogAuxState is introduced
> to
> > > > > build the state like leader epoch sequence and producer snapshots
> > > > > before it starts fetching the data from the leader. We will make it
> > > > > clear in the KIP.
> > > > >
> > > > >
> > > > > 5. Similarly, it would be worth summarizing the behavior on unclean
> > > > leader
> > > > > election. There are several scenarios to consider here: data loss
> from
> > > > > local log, data loss from remote log, data loss from metadata
> topic,
> > > etc.
> > > > > It's worth describing these in detail.
> > > > >
> > > > > We mentioned the cases about unclean leader election in the
> follower
> > > > > fetch scenarios.
> > > > > If there are errors while fetching data from remote store or
> metadata
> > > > > store, it will work the same way as it works with local log. It
> > > > > returns the error back to the caller. Please let us know if I am
> > > > > missing your point here.
> > > > >
> > > > >
> > > > > 7. For a READ_COMMITTED FetchRequest, how do we retrieve and
> return the
> > > > > aborted transaction metadata?
> > > > >
> > > > > When a fetch for a remote log is accessed, we will fetch aborted
> > > > > transactions along with the segment if it is not found in the local
> > > > > index cache. This includes the case of transaction index not
> existing
> > > > > in the remote log segment. That means, the cache entry can be
> empty or
> > > > > have a list of aborted transactions.
> > > > >
> > > > >
> > > > > 8. The `LogSegmentData` class assumes that we have a log segment,
> > > offset
> > > > > index, time index, transaction index, producer snapshot and leader
> > > epoch
> > > > > index. How do we deal with cases where we do not have one or more
> of
> > > > these?
> > > > > For example, we may not have a transaction index or producer
> snapshot
> > > > for a
> > > > > particular segment. The former is optional, and the latter is only
> kept
> > > > for
> > > > > up to the 3 latest segments.
> > > > >
> > > > > This is a good point,  we discussed this in the last meeting.
> > > > > Transaction index is optional and we will copy them only if it
> exists.
> > > > > We want to keep all the producer snapshots at each log segment
> rolling
> > > > > and they can be removed if the log copying is successful and it
> still
> > > > > maintains the existing latest 3 segments, We only delete the
> producer
> > > > > snapshots which have been copied to remote log segments on leader.
> > > > > Follower will keep the log segments beyond the segments which have
> not
> > > > > been copied to remote storage. We will update the KIP with these
> > > > > details.
> > > > >
> > > > > Thanks,
> > > > > Satish.
> > > > >
> > > > > On Thu, Sep 17, 2020 at 1:47 AM Dhruvil Shah <dhruvil@confluent.io
> >
> > > > wrote:
> > > > > >
> > > > > > Hi Satish, Harsha,
> > > > > >
> > > > > > Thanks for the KIP. Few questions below:
> > > > > >
> > > > > > 1. Could you describe how retention would work with this KIP and
> > > which
> > > > > > threads are responsible for driving this work? I believe there
> are 3
> > > > kinds
> > > > > > of retention processes we are looking at:
> > > > > >   (a) Regular retention for data in tiered storage as per
> configured
> > > `
> > > > > > retention.ms` / `retention.bytes`.
> > > > > >   (b) Local retention for data in local storage as per
> configured `
> > > > > > local.log.retention.ms` / `local.log.retention.bytes`
> > > > > >   (c) Possibly regular retention for data in local storage, if
> the
> > > > tiering
> > > > > > task is lagging or for data that is below the log start offset.
> > > > > >
> > > > > > 2. When does a segment become eligible to be tiered? Is it as
> soon as
> > > > the
> > > > > > segment is rolled and the end offset is less than the last stable
> > > > offset as
> > > > > > mentioned in the KIP? I wonder if we need to consider other
> > > parameters
> > > > too,
> > > > > > like the highwatermark so that we are guaranteed that what we are
> > > > tiering
> > > > > > has been committed to the log and accepted by the ISR.
> > > > > >
> > > > > > 3. The section on "Follower Fetch Scenarios" is useful but is a
> bit
> > > > > > difficult to parse at the moment. It would be useful to
> summarize the
> > > > > > changes we need in the ReplicaFetcher.
> > > > > >
> > > > > > 4. Related to the above, it's a bit unclear how we are planning
> on
> > > > > > restoring the producer state for a new replica. Could you expand
> on
> > > > that?
> > > > > >
> > > > > > 5. Similarly, it would be worth summarizing the behavior on
> unclean
> > > > leader
> > > > > > election. There are several scenarios to consider here: data loss
> > > from
> > > > > > local log, data loss from remote log, data loss from metadata
> topic,
> > > > etc.
> > > > > > It's worth describing these in detail.
> > > > > >
> > > > > > 6. It would be useful to add details about how we plan on using
> > > > RocksDB in
> > > > > > the default implementation of `RemoteLogMetadataManager`.
> > > > > >
> > > > > > 7. For a READ_COMMITTED FetchRequest, how do we retrieve and
> return
> > > the
> > > > > > aborted transaction metadata?
> > > > > >
> > > > > > 8. The `LogSegmentData` class assumes that we have a log segment,
> > > > offset
> > > > > > index, time index, transaction index, producer snapshot and
> leader
> > > > epoch
> > > > > > index. How do we deal with cases where we do not have one or
> more of
> > > > these?
> > > > > > For example, we may not have a transaction index or producer
> snapshot
> > > > for a
> > > > > > particular segment. The former is optional, and the latter is
> only
> > > > kept for
> > > > > > up to the 3 latest segments.
> > > > > >
> > > > > > Thanks,
> > > > > > Dhruvil
> > > > > >
> > > > > > On Mon, Sep 7, 2020 at 6:54 PM Harsha Ch <ha...@gmail.com>
> > > wrote:
> > > > > >
> > > > > > > Hi All,
> > > > > > >
> > > > > > > We are all working through the last meeting feedback. I'll
> cancel
> > > the
> > > > > > > tomorrow 's meeting and we can meanwhile continue our
> discussion in
> > > > mailing
> > > > > > > list. We can start the regular meeting from next week onwards.
> > > > > > >
> > > > > > > Thanks,
> > > > > > >
> > > > > > > Harsha
> > > > > > >
> > > > > > > On Fri, Sep 04, 2020 at 8:41 AM, Satish Duggana <
> > > > satish.duggana@gmail.com
> > > > > > > > wrote:
> > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > Hi Jun,
> > > > > > > > Thanks for your thorough review and comments. Please find the
> > > > inline
> > > > > > > > replies below.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > 600. The topic deletion logic needs more details.
> > > > > > > > 600.1 The KIP mentions "The controller considers the topic
> > > > partition is
> > > > > > > > deleted only when it determines that there are no log
> segments
> > > for
> > > > that
> > > > > > > > topic partition by using RLMM". How is this done?
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > It uses RLMM#listSegments() returns all the segments for the
> > > given
> > > > topic
> > > > > > > > partition.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > 600.2 "If the delete option is enabled then the leader will
> stop
> > > > RLM task
> > > > > > > > and stop processing and it sets all the remote log segment
> > > > metadata of
> > > > > > > > that partition with a delete marker and publishes them to
> RLMM."
> > > We
> > > > > > > > discussed this earlier. When a topic is being deleted, there
> may
> > > > not be a
> > > > > > > > leader for the deleted partition.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > This is a good point. As suggested in the meeting, we will
> add a
> > > > separate
> > > > > > > > section for topic/partition deletion lifecycle and this
> scenario
> > > > will be
> > > > > > > > addressed.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > 601. Unclean leader election
> > > > > > > > 601.1 Scenario 1: new empty follower
> > > > > > > > After step 1, the follower restores up to offset 3. So why
> does
> > > it
> > > > have
> > > > > > > > LE-2 <https://issues.apache.org/jira/browse/LE-2> at offset
> 5?
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > Nice catch. It was showing the leader epoch fetched from the
> > > remote
> > > > > > > > storage. It should be shown with the truncated till offset 3.
> > > > Updated the
> > > > > > > > KIP.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > 601.2 senario 5: After Step 3, leader A has inconsistent data
> > > > between its
> > > > > > > > local and the tiered data. For example. offset 3 has msg 3
> LE-0
> > > > <https://issues.apache.org/jira/browse/LE-0> locally,
> > > > > > > > but msg 5 LE-1 <https://issues.apache.org/jira/browse/LE-1>
> in
> > > > the remote store. While it's ok for the unclean leader
> > > > > > > > to lose data, it should still return consistent data, whether
> > > it's
> > > > from
> > > > > > > > the local or the remote store.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > There is no inconsistency here as LE-0
> > > > <https://issues.apache.org/jira/browse/LE-0> offsets are [0, 4] and
> LE-2
> > > > <https://issues.apache.org/jira/browse/LE-2>:
> > > > > > > > [5, ]. It will always get the right records for the given
> offset
> > > > and
> > > > > > > > leader epoch. In case of remote, RSM is invoked to get the
> remote
> > > > log
> > > > > > > > segment that contains the given offset with the leader epoch.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > 601.4 It seems that retention is based on
> > > > > > > > listRemoteLogSegments(TopicPartition topicPartition, long
> > > > leaderEpoch).
> > > > > > > > When there is an unclean leader election, it's possible for
> the
> > > new
> > > > > > > leader
> > > > > > > > to not to include certain epochs in its epoch cache. How are
> > > remote
> > > > > > > > segments associated with those epochs being cleaned?
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > That is a good point. This leader will also cleanup the
> epochs
> > > > earlier to
> > > > > > > > its start leader epoch and delete those segments. It gets the
> > > > earliest
> > > > > > > > epoch for a partition and starts deleting segments from that
> > > leader
> > > > > > > epoch.
> > > > > > > > We need one more API in RLMM to get the earliest leader
> epoch.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > 601.5 The KIP discusses the handling of unclean leader
> elections
> > > > for user
> > > > > > > > topics. What about unclean leader elections on
> > > > > > > > __remote_log_segment_metadata?
> > > > > > > > This is the same as other system topics like
> consumer_offsets,
> > > > > > > > __transaction_state topics. As discussed in the meeting, we
> will
> > > > add the
> > > > > > > > behavior of __remote_log_segment_metadata topic’s unclean
> leader
> > > > > > > > truncation.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > 602. It would be useful to clarify the limitations in the
> initial
> > > > > > > release.
> > > > > > > > The KIP mentions not supporting compacted topics. What about
> JBOD
> > > > and
> > > > > > > > changing the configuration of a topic from delete to compact
> > > after
> > > > > > > remote.
> > > > > > > > log. storage. enable ( http://remote.log.storage.enable/ )
> is
> > > > enabled?
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > This was updated in the KIP earlier.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > 603. RLM leader tasks:
> > > > > > > > 603.1"It checks for rolled over LogSegments (which have the
> last
> > > > message
> > > > > > > > offset less than last stable offset of that topic partition)
> and
> > > > copies
> > > > > > > > them along with their offset/time/transaction indexes and
> leader
> > > > epoch
> > > > > > > > cache to the remote tier." It needs to copy the producer
> snapshot
> > > > too.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > Right. It copies producer snapshots too as mentioned in
> > > > LogSegmentData.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > 603.2 "Local logs are not cleaned up till those segments are
> > > copied
> > > > > > > > successfully to remote even though their retention time/size
> is
> > > > reached"
> > > > > > > > This seems weird. If the tiering stops because the remote
> store
> > > is
> > > > not
> > > > > > > > available, we don't want the local data to grow forever.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > It was clarified in the discussion that the comment was more
> > > about
> > > > the
> > > > > > > > local storage goes beyond the log.retention. The above
> statement
> > > > is about
> > > > > > > > local.log.retention but not for the complete log.retention.
> When
> > > it
> > > > > > > > reaches the log.retention then it will delete the local logs
> even
> > > > though
> > > > > > > > those are not copied to remote storage.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > 604. "RLM maintains a bounded cache(possibly LRU) of the
> index
> > > > files of
> > > > > > > > remote log segments to avoid multiple index fetches from the
> > > remote
> > > > > > > > storage. These indexes can be used in the same way as local
> > > segment
> > > > > > > > indexes are used." Could you provide more details on this?
> Are
> > > the
> > > > > > > indexes
> > > > > > > > cached in memory or on disk? If on disk, where are they
> stored?
> > > > Are the
> > > > > > > > cached indexes bound by a certain size?
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > These are cached on disk and stored in log.dir with a name
> > > > > > > > “__remote_log_index_cache”. They are bound by the total size.
> > > This
> > > > will
> > > > > > > be
> > > > > > > > exposed as a user configuration,
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > 605. BuildingRemoteLogAux
> > > > > > > > 605.1 In this section, two options are listed. Which one is
> > > chosen?
> > > > > > > > Option-2, updated the KIP.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > 605.2 In option 2, it says "Build the local leader epoch
> cache by
> > > > cutting
> > > > > > > > the leader epoch sequence received from remote storage to
> [LSO,
> > > > ELO].
> > > > > > > (LSO
> > > > > > > >
> > > > > > > > = log start offset)." We need to do the same thing for the
> > > producer
> > > > > > > > snapshot. However, it's hard to cut the producer snapshot to
> an
> > > > earlier
> > > > > > > > offset. Another option is to simply take the lastOffset from
> the
> > > > remote
> > > > > > > > segment and use that as the starting fetch offset in the
> > > follower.
> > > > This
> > > > > > > > avoids the need for cutting.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > Right, this was mentioned in the “transactional support”
> section
> > > > about
> > > > > > > > adding these details.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > 606. ListOffsets: Since we need a version bump, could you
> > > document
> > > > it
> > > > > > > > under a protocol change section?
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > Sure, we will update the KIP.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > 607. "LogStartOffset of a topic can point to either of local
> > > > segment or
> > > > > > > > remote segment but it is initialised and maintained in the
> Log
> > > > class like
> > > > > > > > now. This is already maintained in `Log` class while loading
> the
> > > > logs and
> > > > > > > > it can also be fetched from RemoteLogMetadataManager." What
> will
> > > > happen
> > > > > > > to
> > > > > > > > the existing logic (e.g. log recovery) that currently
> depends on
> > > > > > > > logStartOffset but assumes it's local?
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > They use a field called localLogStartOffset which is the
> local
> > > log
> > > > start
> > > > > > > > offset..
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > 608. Handle expired remote segment: How does it pick up new
> > > > > > > logStartOffset
> > > > > > > > from deleteRecords?
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > Good point. This was not addressed in the KIP. Will update
> the
> > > KIP
> > > > on how
> > > > > > > > the RLM task handles this scenario.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > 609. RLMM message format:
> > > > > > > > 609.1 It includes both MaxTimestamp and EventTimestamp. Where
> > > does
> > > > it get
> > > > > > > > both since the message in the log only contains one
> timestamp?
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > `EventTimeStamp` is the timestamp at which that segment
> metadata
> > > > event is
> > > > > > > > generated. This is more for audits.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > 609.2 If we change just the state (e.g. to DELETE_STARTED),
> it
> > > > seems it's
> > > > > > > > wasteful to have to include all other fields not changed.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > This is a good point. We thought about incremental updates.
> But
> > > we
> > > > want
> > > > > > > to
> > > > > > > > make sure all the events are in the expected order and take
> > > action
> > > > based
> > > > > > > > on the latest event. Will think through the approaches in
> detail
> > > > and
> > > > > > > > update here.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > 609.3 Could you document which process makes the following
> > > > transitions
> > > > > > > > DELETE_MARKED, DELETE_STARTED, DELETE_FINISHED?
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > Okay, will document more details.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > 610. remote.log.reader.max.pending.tasks: "Maximum remote log
> > > > reader
> > > > > > > > thread pool task queue size. If the task queue is full,
> broker
> > > > will stop
> > > > > > > > reading remote log segments." What does the broker do if the
> > > queue
> > > > is
> > > > > > > > full?
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > It returns an error for this topic partition.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > 611. What do we return if the request offset/epoch doesn't
> exist
> > > > in the
> > > > > > > > following API?
> > > > > > > > RemoteLogSegmentMetadata
> remoteLogSegmentMetadata(TopicPartition
> > > > > > > > topicPartition, long offset, int epochForOffset)
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > This returns null. But we prefer to update the return type as
> > > > Optional
> > > > > > > and
> > > > > > > > return Empty if that does not exist.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > Thanks,
> > > > > > > > Satish.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > On Tue, Sep 1, 2020 at 9:45 AM Jun Rao < jun@ confluent. io
> (
> > > > > > > > jun@confluent.io ) > wrote:
> > > > > > > >
> > > > > > > >
> > > > > > > >>
> > > > > > > >>
> > > > > > > >> Hi, Satish,
> > > > > > > >>
> > > > > > > >>
> > > > > > > >>
> > > > > > > >> Thanks for the updated KIP. Made another pass. A few more
> > > comments
> > > > > > > below.
> > > > > > > >>
> > > > > > > >>
> > > > > > > >>
> > > > > > > >> 600. The topic deletion logic needs more details.
> > > > > > > >> 600.1 The KIP mentions "The controller considers the topic
> > > > partition is
> > > > > > > >> deleted only when it determines that there are no log
> segments
> > > > for that
> > > > > > > >> topic partition by using RLMM". How is this done? 600.2 "If
> the
> > > > delete
> > > > > > > >> option is enabled then the leader will stop RLM task and
> stop
> > > > processing
> > > > > > > >> and it sets all the remote log segment metadata of that
> > > partition
> > > > with a
> > > > > > > >> delete marker and publishes them to RLMM." We discussed this
> > > > earlier.
> > > > > > > When
> > > > > > > >> a topic is being deleted, there may not be a leader for the
> > > > deleted
> > > > > > > >> partition.
> > > > > > > >>
> > > > > > > >>
> > > > > > > >>
> > > > > > > >> 601. Unclean leader election
> > > > > > > >> 601.1 Scenario 1: new empty follower
> > > > > > > >> After step 1, the follower restores up to offset 3. So why
> does
> > > > it have
> > > > > > > >> LE-2 <https://issues.apache.org/jira/browse/LE-2> at
> offset 5?
> > > > > > > >> 601.2 senario 5: After Step 3, leader A has inconsistent
> data
> > > > between
> > > > > > > its
> > > > > > > >> local and the tiered data. For example. offset 3 has msg 3
> LE-0
> > > > <https://issues.apache.org/jira/browse/LE-0> locally,
> > > > > > > >> but msg 5 LE-1 <https://issues.apache.org/jira/browse/LE-1>
> in
> > > > the remote store. While it's ok for the unclean leader
> > > > > > > >> to lose data, it should still return consistent data,
> whether
> > > > it's from
> > > > > > > >> the local or the remote store.
> > > > > > > >> 601.3 The follower picks up log start offset using the
> following
> > > > api.
> > > > > > > >> Suppose that we have 3 remote segments (LE,
> SegmentStartOffset)
> > > > as (2,
> > > > > > > >> 10),
> > > > > > > >> (3, 20) and (7, 15) due to an unclean leader election.
> Using the
> > > > > > > following
> > > > > > > >> api will cause logStartOffset to go backward from 20 to 15.
> How
> > > > do we
> > > > > > > >> prevent that?
> > > > > > > >> earliestLogOffset(TopicPartition topicPartition, int
> > > leaderEpoch)
> > > > 601.4
> > > > > > > It
> > > > > > > >> seems that retention is based on
> > > > > > > >> listRemoteLogSegments(TopicPartition topicPartition, long
> > > > leaderEpoch).
> > > > > > > >> When there is an unclean leader election, it's possible for
> the
> > > > new
> > > > > > > leader
> > > > > > > >> to not to include certain epochs in its epoch cache. How are
> > > > remote
> > > > > > > >> segments associated with those epochs being cleaned? 601.5
> The
> > > KIP
> > > > > > > >> discusses the handling of unclean leader elections for user
> > > > topics. What
> > > > > > > >> about unclean leader elections on
> > > > > > > >> __remote_log_segment_metadata?
> > > > > > > >>
> > > > > > > >>
> > > > > > > >>
> > > > > > > >> 602. It would be useful to clarify the limitations in the
> > > initial
> > > > > > > release.
> > > > > > > >> The KIP mentions not supporting compacted topics. What about
> > > JBOD
> > > > and
> > > > > > > >> changing the configuration of a topic from delete to compact
> > > after
> > > > > > > remote.
> > > > > > > >> log. storage. enable ( http://remote.log.storage.enable/ )
> is
> > > > enabled?
> > > > > > > >>
> > > > > > > >>
> > > > > > > >>
> > > > > > > >> 603. RLM leader tasks:
> > > > > > > >> 603.1"It checks for rolled over LogSegments (which have the
> last
> > > > message
> > > > > > > >> offset less than last stable offset of that topic
> partition) and
> > > > copies
> > > > > > > >> them along with their offset/time/transaction indexes and
> leader
> > > > epoch
> > > > > > > >> cache to the remote tier." It needs to copy the producer
> > > snapshot
> > > > too.
> > > > > > > >> 603.2 "Local logs are not cleaned up till those segments are
> > > > copied
> > > > > > > >> successfully to remote even though their retention
> time/size is
> > > > reached"
> > > > > > > >> This seems weird. If the tiering stops because the remote
> store
> > > > is not
> > > > > > > >> available, we don't want the local data to grow forever.
> > > > > > > >>
> > > > > > > >>
> > > > > > > >>
> > > > > > > >> 604. "RLM maintains a bounded cache(possibly LRU) of the
> index
> > > > files of
> > > > > > > >> remote log segments to avoid multiple index fetches from the
> > > > remote
> > > > > > > >> storage. These indexes can be used in the same way as local
> > > > segment
> > > > > > > >> indexes are used." Could you provide more details on this?
> Are
> > > the
> > > > > > > indexes
> > > > > > > >> cached in memory or on disk? If on disk, where are they
> stored?
> > > > Are the
> > > > > > > >> cached indexes bound by a certain size?
> > > > > > > >>
> > > > > > > >>
> > > > > > > >>
> > > > > > > >> 605. BuildingRemoteLogAux
> > > > > > > >> 605.1 In this section, two options are listed. Which one is
> > > > chosen?
> > > > > > > 605.2
> > > > > > > >> In option 2, it says "Build the local leader epoch cache by
> > > > cutting the
> > > > > > > >> leader epoch sequence received from remote storage to [LSO,
> > > ELO].
> > > > (LSO
> > > > > > > >> = log start offset)." We need to do the same thing for the
> > > > producer
> > > > > > > >> snapshot. However, it's hard to cut the producer snapshot
> to an
> > > > earlier
> > > > > > > >> offset. Another option is to simply take the lastOffset
> from the
> > > > remote
> > > > > > > >> segment and use that as the starting fetch offset in the
> > > > follower. This
> > > > > > > >> avoids the need for cutting.
> > > > > > > >>
> > > > > > > >>
> > > > > > > >>
> > > > > > > >> 606. ListOffsets: Since we need a version bump, could you
> > > > document it
> > > > > > > >> under a protocol change section?
> > > > > > > >>
> > > > > > > >>
> > > > > > > >>
> > > > > > > >> 607. "LogStartOffset of a topic can point to either of local
> > > > segment or
> > > > > > > >> remote segment but it is initialised and maintained in the
> Log
> > > > class
> > > > > > > like
> > > > > > > >> now. This is already maintained in `Log` class while
> loading the
> > > > logs
> > > > > > > and
> > > > > > > >> it can also be fetched from RemoteLogMetadataManager." What
> will
> > > > happen
> > > > > > > to
> > > > > > > >> the existing logic (e.g. log recovery) that currently
> depends on
> > > > > > > >> logStartOffset but assumes it's local?
> > > > > > > >>
> > > > > > > >>
> > > > > > > >>
> > > > > > > >> 608. Handle expired remote segment: How does it pick up new
> > > > > > > logStartOffset
> > > > > > > >> from deleteRecords?
> > > > > > > >>
> > > > > > > >>
> > > > > > > >>
> > > > > > > >> 609. RLMM message format:
> > > > > > > >> 609.1 It includes both MaxTimestamp and EventTimestamp.
> Where
> > > > does it
> > > > > > > get
> > > > > > > >> both since the message in the log only contains one
> timestamp?
> > > > 609.2 If
> > > > > > > we
> > > > > > > >> change just the state (e.g. to DELETE_STARTED), it seems
> it's
> > > > wasteful
> > > > > > > to
> > > > > > > >> have to include all other fields not changed. 609.3 Could
> you
> > > > document
> > > > > > > >> which process makes the following transitions DELETE_MARKED,
> > > > > > > >> DELETE_STARTED, DELETE_FINISHED?
> > > > > > > >>
> > > > > > > >>
> > > > > > > >>
> > > > > > > >> 610. remote.log.reader.max.pending.tasks: "Maximum remote
> log
> > > > reader
> > > > > > > >> thread pool task queue size. If the task queue is full,
> broker
> > > > will stop
> > > > > > > >> reading remote log segments." What does the broker do if the
> > > > queue is
> > > > > > > >> full?
> > > > > > > >>
> > > > > > > >>
> > > > > > > >>
> > > > > > > >> 611. What do we return if the request offset/epoch doesn't
> exist
> > > > in the
> > > > > > > >> following API?
> > > > > > > >> RemoteLogSegmentMetadata
> remoteLogSegmentMetadata(TopicPartition
> > > > > > > >> topicPartition, long offset, int epochForOffset)
> > > > > > > >>
> > > > > > > >>
> > > > > > > >>
> > > > > > > >> Jun
> > > > > > > >>
> > > > > > > >>
> > > > > > > >>
> > > > > > > >> On Mon, Aug 31, 2020 at 11:19 AM Satish Duggana < satish.
> > > duggana@
> > > > > > > gmail. com
> > > > > > > >> ( satish.duggana@gmail.com ) > wrote:
> > > > > > > >>
> > > > > > > >>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>> KIP is updated with
> > > > > > > >>> - Remote log segment metadata topic message format/schema.
> > > > > > > >>> - Added remote log segment metadata state transitions and
> > > > explained how
> > > > > > > >>> the deletion of segments is handled, including the case of
> > > > partition
> > > > > > > >>> deletions.
> > > > > > > >>> - Added a few more limitations in the "Non goals" section.
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>> Thanks,
> > > > > > > >>> Satish.
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>> On Thu, Aug 27, 2020 at 12:42 AM Harsha Ch < harsha. ch@
> > > gmail.
> > > > com (
> > > > > > > >>> harsha.ch@gmail.com ) > wrote:
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>>
> > > > > > > >>>>
> > > > > > > >>>> Updated the KIP with Meeting Notes section
> > > > > > > >>>>
> > > > > > > >>>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>> https:/ / cwiki. apache. org/ confluence/ display/ KAFKA/
> > > > > > > KIP-405 <https://issues.apache.org/jira/browse/KIP-405>
> > > > %3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> > > > > > > >>> (
> > > > > > > >>>
> > > > > > >
> > > >
> > >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-405%3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> > > > > > > >>> )
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>>
> > > > > > > >>>>
> > > > > > > >>>> On Tue, Aug 25, 2020 at 1:03 PM Jun Rao < jun@
> confluent. io
> > > (
> > > > > > > >>>> jun@confluent.io ) > wrote:
> > > > > > > >>>>
> > > > > > > >>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>> Hi, Harsha,
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>> Thanks for the summary. Could you add the summary and the
> > > > recording
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>
> > > > > > > >>>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>> link to
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>> the last section of
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>
> > > > > > > >>>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>> https:/ / cwiki. apache. org/ confluence/ display/ KAFKA/
> > > > > > > Kafka+Improvement+Proposals
> > > > > > > >>> (
> > > > > > > >>>
> > > > > > >
> > > >
> > >
> https://cwiki.apache.org/confluence/display/KAFKA/Kafka+Improvement+Proposals
> > > > > > > >>> )
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>> ?
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>> Jun
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>> On Tue, Aug 25, 2020 at 11:12 AM Harsha Chintalapani <
> kafka@
> > > > > > > harsha. io (
> > > > > > > >>>>> kafka@harsha.io ) > wrote:
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>> Thanks everyone for attending the meeting today.
> > > > > > > >>>>>> Here is the recording
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>
> > > > > > > >>>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>> https:/ / drive. google. com/ file/ d/
> > > > > > > 14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/ view?usp=sharing
> > > > > > > >>> (
> > > > > > > >>>
> > > > > > >
> > > >
> > >
> https://drive.google.com/file/d/14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/view?usp=sharing
> > > > > > > >>> )
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>>
> > > > > > > >>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>> Notes:
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>> 1. KIP is updated with follower fetch protocol and
> ready to
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>
> > > > > > > >>>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>> reviewed
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>>
> > > > > > > >>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>> 2. Satish to capture schema of internal metadata topic
> in
> > > the
> > > > KIP
> > > > > > > >>>>>> 3. We will update the KIP with details of different
> cases
> > > > > > > >>>>>> 4. Test plan will be captured in a doc and will add to
> the
> > > KIP
> > > > > > > >>>>>> 5. Add a section "Limitations" to capture the
> capabilities
> > > > that
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>
> > > > > > > >>>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>> will
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>> be
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>> introduced with this KIP and what will not be covered in
> > > this
> > > > KIP.
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>> Please add to it I missed anything. Will produce a
> formal
> > > > meeting
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>
> > > > > > > >>>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>> notes
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>>
> > > > > > > >>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>> from next meeting onwards.
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>> Thanks,
> > > > > > > >>>>>> Harsha
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>> On Mon, Aug 24, 2020 at 9:42 PM, Ying Zheng < yingz@
> uber.
> > > > com.
> > > > > > > invalid (
> > > > > > > >>>>>> yingz@uber.com.invalid ) > wrote:
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> We did some basic feature tests at Uber. The test
> cases and
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>
> > > > > > > >>>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>> results are
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>>
> > > > > > > >>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> shared in this google doc:
> > > > > > > >>>>>>> https:/ / docs. google. com/ spreadsheets/ d/ (
> > > > > > > >>>>>>> https://docs.google.com/spreadsheets/d/ )
> > > > > > > >>>>>>>
> > > 1XhNJqjzwXvMCcAOhEH0sSXU6RTvyoSf93DHF-YMfGLk/edit?usp=sharing
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> The performance test results were already shared in
> the KIP
> > > > last
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>
> > > > > > > >>>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>> month.
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>>
> > > > > > > >>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> On Mon, Aug 24, 2020 at 11:10 AM Harsha Ch < harsha.
> ch@
> > > > gmail.
> > > > > > > com (
> > > > > > > >>>>>>> harsha.ch@gmail.com ) >
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>> wrote:
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> "Understand commitments towards driving design &
> > > > implementation of
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>
> > > > > > > >>>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>> the
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>>
> > > > > > > >>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>> KIP
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> further and how it aligns with participant interests in
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>
> > > > > > > >>>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>> contributing to
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>>
> > > > > > > >>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>> the
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> efforts (ex: in the context of Uber’s Q3/Q4 roadmap)."
> What
> > > > is that
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>> about?
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> On Mon, Aug 24, 2020 at 11:05 AM Kowshik Prakasam <
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>> kprakasam@ confluent. io ( kprakasam@confluent.io ) >
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> wrote:
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> Hi Harsha,
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> The following google doc contains a proposal for
> temporary
> > > > agenda
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>
> > > > > > > >>>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>> for
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>> the
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> KIP-405 <https://issues.apache.org/jira/browse/KIP-405>
> <
> > > > https:/ / issues. apache. org/ jira/ browse/ KIP-405
> > > > <https://issues.apache.org/jira/browse/KIP-405> (
> > > > > > > >>>>>>> https://issues.apache.org/jira/browse/KIP-405 ) > sync
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>
> > > > > > > >>>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>> meeting
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>>
> > > > > > > >>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> tomorrow:
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> https:/ / docs. google. com/ document/ d/ (
> > > > > > > >>>>>>> https://docs.google.com/document/d/ )
> > > > > > > >>>>>>> 1pqo8X5LU8TpwfC_iqSuVPezhfCfhGkbGN2TqiPA3LBU/edit
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> .
> > > > > > > >>>>>>> Please could you add it to the Google calendar invite?
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> Thank you.
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> Cheers,
> > > > > > > >>>>>>> Kowshik
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> On Thu, Aug 20, 2020 at 10:58 AM Harsha Ch < harsha.
> ch@
> > > > gmail.
> > > > > > > com (
> > > > > > > >>>>>>> harsha.ch@gmail.com ) >
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>> wrote:
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> Hi All,
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> Scheduled a meeting for Tuesday 9am - 10am. I can
> record
> > > and
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>
> > > > > > > >>>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>> upload for
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>>
> > > > > > > >>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> community to be able to follow the discussion.
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> Jun, please add the required folks on confluent side.
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> Thanks,
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> Harsha
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> On Thu, Aug 20, 2020 at 12:33 AM, Alexandre Dupriez <
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>> alexandre.dupriez@
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> gmail. com ( http://gmail.com/ ) > wrote:
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> Hi Jun,
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> Many thanks for your initiative.
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> If you like, I am happy to attend at the time you
> > > suggested.
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> Many thanks,
> > > > > > > >>>>>>> Alexandre
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> Le mer. 19 août 2020 à 22:00, Harsha Ch < harsha. ch@
> > > > gmail. com (
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>> harsha.
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> ch@ gmail. com ( ch@gmail.com ) ) > a écrit :
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> Hi Jun,
> > > > > > > >>>>>>> Thanks. This will help a lot. Tuesday will work for us.
> > > > > > > >>>>>>> -Harsha
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> On Wed, Aug 19, 2020 at 1:24 PM Jun Rao < jun@
> confluent.
> > > > io (
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>
> > > > > > > >>>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>> jun@
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>>
> > > > > > > >>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> confluent. io ( http://confluent.io/ ) ) > wrote:
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> Hi, Satish, Ying, Harsha,
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> Do you think it would be useful to have a regular
> virtual
> > > > meeting
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>
> > > > > > > >>>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>> to
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>>
> > > > > > > >>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> discuss this KIP? The goal of the meeting will be
> sharing
> > > > > > > >>>>>>> design/development progress and discussing any open
> issues
> > > to
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> accelerate
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> this KIP. If so, will every Tuesday (from next week)
> > > 9am-10am
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> PT
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> work for you? I can help set up a Zoom meeting, invite
> > > > everyone who
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> might
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> be interested, have it recorded and shared, etc.
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> Thanks,
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> Jun
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> On Tue, Aug 18, 2020 at 11:01 AM Satish Duggana <
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> satish. duggana@ gmail. com ( satish. duggana@ gmail.
> com
> > > (
> > > > > > > >>>>>>> satish.duggana@gmail.com ) ) >
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> wrote:
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> Hi Kowshik,
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> Thanks for looking into the KIP and sending your
> comments.
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> 5001. Under the section "Follower fetch protocol in
> > > detail",
> > > > the
> > > > > > > >>>>>>> next-local-offset is the offset upto which the
> segments are
> > > > copied
> > > > > > > >>>>>>>
> > > >
>

Re: [DISCUSS] KIP-405: Kafka Tiered Storage

[Israel Ekpo <is...@gmail.com>]

This is a very cool KIP.

It is going to have a significant impact on how Kafka is deployed and used
once it becomes implemented and available.

I am very interested in integrating/implementing the support for Azure Blob
Storage for this KIP as well. So far I have not seen any details about that
in the JIRA items.

I noticed there are recordings and written discussions, I would like to
participate in future discussions if possible.

Thanks for the great work.

On Mon, Jan 11, 2021 at 8:37 PM Jun Rao <ju...@confluent.io> wrote:

> Hi, Satish,
>
> Thanks for the reply. A few more followup comments.
>
> 6000. Since we are returning new error codes, we need to bump up the
> protocol version for Fetch request. Also, it will be useful to document all
> new error codes and whether they are retriable or not.
> This previous comment doesn't seem to be addressed.
>
> 9110. flat_file_format: Could you define the serialized representation for
> each field in the header?
>
> 9111. RPM has the following 2 steps.
> "1. The controller publishes delete_partition_marked event to say that the
> partition is marked for deletion. There can be multiple events published
> when the controller restarts or failover and this event will be
> deduplicated by RPM.
> 2. RPM receives the delete_partition_marked and processes it if it is not
> yet processed earlier."
> What triggers RPM to read __remote_log_metadata? Is RPM part of the default
> RLMM implementation or is it meant for any RLMM implementation?
>
> 9112. remote.log.manager.task.retry.backoff.ms: It would be useful to make
> it clear in the comment that this is for the initial retry backoff.
>
> 9113. RLMM:
> 9113.1 updateRemoteLogSegmentMetadata(): This comment needs to be updated.
> 9113.2 Should RemoteLogSegmentMetadataUpdate include a leadeEpoch field
> since all other update events have leaderEpoch?
> 9113.3 Could we rename RemotePartitionState to RemotePartitionDeleteState
> to make it clear this is for deletion?
> 9113.4 Could we rename RemoteLogState to RemoteLogSegmentState to make it
> clear this is for segment?
>
> 9114.Upgrade:
> 9114.1 It seems that we require message format > 0.11 for turning on the
> remote store feature.
> 9114.2 It's not clear to me why remote.log.storage.system.enable needs to
> be set to true before bumping up inter.broker.protocol.version.
> 9114.3 "If the topic-id is not received in the LeaderAndIsr request then
> remote log storage will not start. But it will log an error message in the
> log. One way to address this is to do a rolling restart of that broker, so
> that the leader will be moved to another broker and the controller will
> send LeaderAndIsr with the registered topic-id." Why is this needed? With
> KIP-516, after upgrading to the latest protocol, topicIds are auto created.
>
> 9115. testing: Could you comment on how we plan to do integration and
> system tests? Do we plan to include, for example, an in-memory
> implementation of RSM?
>
> 9116. There is still a todo for the message formatter.
>
> Jun
>
> On Sat, Jan 9, 2021 at 2:04 AM Satish Duggana <sa...@gmail.com>
> wrote:
>
> > Hi Jun,
> > Thanks for your comments. Please find the inline replies below.
> >
> > 6022. For packages used for server plugins, the convention is to
> > use org.apache.kafka.server. See java-based Authorizer as an example.
> >
> > Sure, ‘org.apache.kafka.common.log.remote.storage’ renamed to
> > ‘org.apache.kafka.server.log.remote.storage’.  Updated in the KIP.
> >
> > 9100. Do we need DeletePartitionStateRecord in flat_file_format? The flat
> > file captures the state of the remote segments. After a partition is
> > deleted, it seems that we just need to remove the partitions's remote
> > segments from the flat file.
> >
> > DeletePartitionState might not yet have been processed by RPM and not
> > completed. We  will not have  that in flat  file format  once it
> > reaches DELETE_PARTITION_FINISHED state.
> >
> > 9101. Upgrade: It will be useful to allow direct upgrade from an old
> > version. It seems that's doable. One can just do the normal upgrade first
> > and wait enough time (for producer snapshots to be built), and then
> enable
> > remote storage.
> >
> > Upgrade notes updates in the KIP.
> >
> > 9102. RemotePartitionRemover(RPM) process: Is it true that RPM starts
> > tracking the remote segments when RLMM.onPartitionLeadershipChanges() is
> > called with the broker being the leader for __remote_log_metadata
> > partition? If so, could we document it?
> >
> > The current plan is to have that as part of RLMM and RPM uses that to
> > get the remote segments list. I will add this detail in the respective
> > sections.
> >
> > Satish.
> >
> > On Wed, 16 Dec 2020 at 23:55, Jun Rao <ju...@confluent.io> wrote:
> > >
> > > Hi, Satish,
> > >
> > > Thanks for the reply. A few more followup comments.
> > >
> > > 6022. For packages used for server plugins, the convention is to
> > > use org.apache.kafka.server. See java-based Authorizer as an example.
> > >
> > > 9100. Do we need DeletePartitionStateRecord in flat_file_format? The
> flat
> > > file captures the state of the remote segments. After a partition is
> > > deleted, it seems that we just need to remove the partitions's remote
> > > segments from the flat file.
> > >
> > > 9101. Upgrade: It will be useful to allow direct upgrade from an old
> > > version. It seems that's doable. One can just do the normal upgrade
> first
> > > and wait enough time (for producer snapshots to be built), and then
> > enable
> > > remote storage.
> > >
> > > 9102. RemotePartitionRemover(RPM) process: Is it true that RPM starts
> > > tracking the remote segments when RLMM.onPartitionLeadershipChanges()
> is
> > > called with the broker being the leader for __remote_log_metadata
> > > partition? If so, could we document it?
> > >
> > > Jun
> > >
> > > On Tue, Dec 15, 2020 at 8:47 AM Kowshik Prakasam <
> kprakasam@confluent.io
> > >
> > > wrote:
> > >
> > > > Hi Satish,
> > > >
> > > > Thanks for the updates! A few more comments below.
> > > >
> > > > 9001. Under the "Upgrade" section, there is a line mentioning:
> > "Upgrade the
> > > > existing Kafka cluster to 2.7 version and allow this to run for the
> log
> > > > retention of user topics that you want to enable tiered storage. This
> > will
> > > > allow all the topics to have the producer snapshots generated for
> each
> > log
> > > > segment." -- Which associated change in AK were you referring to
> here?
> > Is
> > > > it: https://github.com/apache/kafka/pull/7929 ? It seems like I
> don't
> > see
> > > > it in the 2.7 release branch yet, here is the link:
> > > > https://github.com/apache/kafka/commits/2.7.
> > > >
> > > > 9002. Under the "Upgrade" section, the configuration mentioned is
> > > > 'remote.log.storage.system.enable'. However, under "Public
> Interfaces"
> > > > section the corresponding configuration is
> > 'remote.storage.system.enable'.
> > > > Could we use the same one in both, maybe
> > > > 'remote.log.storage.system.enable'?
> > > >
> > > > 9003. Under "Per Topic Configuration", the KIP recommends setting
> > > > 'remote.log.storage.enable' to true at a per-topic level. It will be
> > useful
> > > > to add a line that if the user wants to enable it for all topics,
> then
> > they
> > > > should be able to set the cluster-wide default to true. Also, it will
> > be
> > > > useful to mention that the KIP currently does not support setting it
> to
> > > > false (after it is set to true), and add that to the future work
> > section.
> > > >
> > > > 9004. Under "Committed offsets file format", the sample provided
> shows
> > > > partition number and offset. Is the topic name required for
> identifying
> > > > which topic the partitions belong to?
> > > >
> > > > 9005. Under "Internal flat-file store format of remote log metadata",
> > it
> > > > seems useful to specify both topic name and topic ID for debugging
> > > > purposes.
> > > >
> > > > 9006. Under "Internal flat-file store format of remote log metadata",
> > the
> > > > description of "metadata-topic-offset" currently says "offset of the
> > remote
> > > > log metadata topic from which this topic partition's remote log
> > metadata is
> > > > fetched." Just for the wording, perhaps you meant to refer to the
> > offset
> > > > upto which the file has been committed? i.e. "offset of the remote
> log
> > > > metadata topic upto which this topic partition's remote log metadata
> > has
> > > > been committed into this file."
> > > >
> > > > 9007. Under "Internal flat-file store format of remote log metadata",
> > the
> > > > schema of the payload (i.e. beyond the header) seems to contain the
> > events
> > > > from the metadata topic. It seems useful to instead persist the
> > > > representation of the materialized state of the events, so that for
> the
> > > > same segment only the latest state is stored. Besides reducing
> storage
> > > > footprint, this also is likely to relate directly with the in-memory
> > > > representation of the RLMM cache (which probably is some kind of a
> Map
> > with
> > > > key being segment ID and value being the segment state), so recovery
> > from
> > > > disk will be straightforward.
> > > >
> > > > 9008. Under "Topic deletion lifecycle", step (1), it will be useful
> to
> > > > mention when in the deletion flow does the controller publish the
> > > > delete_partition_marked event to say that the partition is marked for
> > > > deletion?
> > > >
> > > > 9009. There are ~4 TODOs in the KIP. Could you please address these
> or
> > > > remove them?
> > > >
> > > > 9010. There is a reference to a Google doc on the KIP which was used
> > > > earlier for discussions. Please could you remove the reference, since
> > the
> > > > KIP is the source of the truth?
> > > >
> > > > 9011. This feedback is from an earlier comment. In the
> > RemoteStorageManager
> > > > interface, there is an API defined for each file type. For example,
> > > > fetchOffsetIndex, fetchTimestampIndex etc. To avoid the duplication,
> > I'd
> > > > suggest we can instead have a FileType enum and a common get API
> based
> > on
> > > > the FileType. What do you think?
> > > >
> > > >
> > > > Cheers,
> > > > Kowshik
> > > >
> > > >
> > > > On Mon, Dec 14, 2020 at 11:07 AM Satish Duggana <
> > satish.duggana@gmail.com>
> > > > wrote:
> > > >
> > > > > Hi Jun,
> > > > > Thanks for your comments. Please go through the inline replies.
> > > > >
> > > > >
> > > > > 5102.2: It seems that both positions can just be int. Another
> option
> > is
> > > > to
> > > > > have two methods. Would it be clearer?
> > > > >
> > > > >     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> > > > > remoteLogSegmentMetadata,  int startPosition)
> > > > throwsRemoteStorageException;
> > > > >
> > > > >     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> > > > > remoteLogSegmentMetadata, int startPosition, int endPosition)
> throws
> > > > > RemoteStorageException;
> > > > >
> > > > > That makes sense to me, updated the KIP.
> > > > >
> > > > > 6003: Could you also update the javadoc for the return value?
> > > > >
> > > > > Updated.
> > > > >
> > > > > 6020: local.log.retention.bytes: Should it default to
> > log.retention.bytes
> > > > > to be consistent with local.log.retention.ms?
> > > > >
> > > > > Yes, it can be defaulted to log.retention.bytes.
> > > > >
> > > > > 6021: Could you define TopicIdPartition?
> > > > >
> > > > > Added TopicIdPartition in the KIP.
> > > > >
> > > > > 6022: For all public facing classes, could you specify the package
> > name?
> > > > >
> > > > > Updated.
> > > > >
> > > > >
> > > > > Thanks,
> > > > > Satish.
> > > > >
> > > > > On Tue, Dec 8, 2020 at 12:59 AM Jun Rao <ju...@confluent.io> wrote:
> > > > > >
> > > > > > Hi, Satish,
> > > > > >
> > > > > > Thanks for the reply. A few more comments below.
> > > > > >
> > > > > > 5102.2: It seems that both positions can just be int. Another
> > option is
> > > > > to
> > > > > > have two methods. Would it be clearer?
> > > > > >
> > > > > >     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> > > > > > remoteLogSegmentMetadata,
> > > > > >                                     int startPosition) throws
> > > > > > RemoteStorageException;
> > > > > >
> > > > > >     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> > > > > > remoteLogSegmentMetadata,
> > > > > >                                     int startPosition, int
> > endPosition)
> > > > > > throws RemoteStorageException;
> > > > > >
> > > > > > 6003: Could you also update the javadoc for the return value?
> > > > > >
> > > > > > 6010: What kind of tiering throughput have you seen with 5
> threads?
> > > > > >
> > > > > > 6020: local.log.retention.bytes: Should it default to
> > > > log.retention.bytes
> > > > > > to be consistent with local.log.retention.ms?
> > > > > >
> > > > > > 6021: Could you define TopicIdPartition?
> > > > > >
> > > > > > 6022: For all public facing classes, could you specify the
> package
> > > > name?
> > > > > >
> > > > > > It seems that you already added the topicId support. Two other
> > > > remaining
> > > > > > items are (a) the format of local tier metadata storage and (b)
> > > > upgrade.
> > > > > >
> > > > > > Jun
> > > > > >
> > > > > > On Mon, Dec 7, 2020 at 8:56 AM Satish Duggana <
> > > > satish.duggana@gmail.com>
> > > > > > wrote:
> > > > > >
> > > > > > > Hi Jun,
> > > > > > > Thanks for your comments. Please find the inline replies below.
> > > > > > >
> > > > > > > >605.2 It's rare for the follower to need the remote data. So,
> > the
> > > > > current
> > > > > > > approach is fine too. Could you document the process of
> > rebuilding
> > > > the
> > > > > > > producer state since we can't simply trim the producerState to
> an
> > > > > offset in
> > > > > > > the middle of a segment.
> > > > > > >
> > > > > > > Will clarify in the KIP.
> > > > > > >
> > > > > > > >5102.2 Would it be clearer to make startPosiont long and
> > endPosition
> > > > > of
> > > > > > > Optional<Long>?
> > > > > > >
> > > > > > > We will have arg checks with respective validation. It is not a
> > good
> > > > > > > practice to have arguments with optional as mentioned here.
> > > > > > > https://rules.sonarsource.com/java/RSPEC-3553
> > > > > > >
> > > > > > >
> > > > > > > >5102.5 LogSegmentData still has leaderEpochIndex as File
> > instead of
> > > > > > > ByteBuffer.
> > > > > > >
> > > > > > > Updated.
> > > > > > >
> > > > > > > >5102.7 Could you define all public methods for LogSegmentData?
> > > > > > >
> > > > > > > Updated.
> > > > > > >
> > > > > > > >5103.5 Could you change the reference to
> > rlm_process_interval_ms and
> > > > > > > rlm_retry_interval_ms to the new config names? Also, the retry
> > > > interval
> > > > > > > config seems still missing. It would be useful to support
> > exponential
> > > > > > > backoff with the retry interval config.
> > > > > > >
> > > > > > > Good point. We wanted the retry with truncated exponential
> > backoff,
> > > > > > > updated the KIP.
> > > > > > >
> > > > > > > >5111. "RLM follower fetches the earliest offset for the
> earliest
> > > > > leader
> > > > > > > epoch by calling RLMM.earliestLogOffset(TopicPartition
> > > > topicPartition,
> > > > > int
> > > > > > > leaderEpoch) and updates that as the log start offset." This
> > text is
> > > > > still
> > > > > > > there. Also, could we remove earliestLogOffset() from RLMM?
> > > > > > >
> > > > > > > Updated.
> > > > > > >
> > > > > > > >5115. There are still references to "remote log cleaners".
> > > > > > >
> > > > > > > Updated.
> > > > > > >
> > > > > > > >6000. Since we are returning new error codes, we need to bump
> > up the
> > > > > > > protocol version for Fetch request. Also, it will be useful to
> > > > > document all
> > > > > > > new error codes and whether they are retriable or not.
> > > > > > >
> > > > > > > Sure, we will add that in the KIP.
> > > > > > >
> > > > > > > >6001. public Map<Long, Long> segmentLeaderEpochs(): Currently,
> > > > > leaderEpoch
> > > > > > > is int32 instead of long.
> > > > > > >
> > > > > > > Updated.
> > > > > > >
> > > > > > > >6002. Is RemoteLogSegmentMetadata.markedForDeletion() needed
> > given
> > > > > > > RemoteLogSegmentMetadata.state()?
> > > > > > >
> > > > > > > No, it is fixed.
> > > > > > >
> > > > > > > >6003. RemoteLogSegmentMetadata
> > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > topicPartition, long offset, int epochForOffset): Should this
> > return
> > > > > > > Optional<RemoteLogSegmentMetadata>?
> > > > > > >
> > > > > > > That makes sense, updated.
> > > > > > >
> > > > > > > >6005. RemoteLogState: It seems it's better to split it between
> > > > > > > DeletePartitionUpdate and RemoteLogSegmentMetadataUpdate since
> > the
> > > > > states
> > > > > > > are never shared between the two use cases.
> > > > > > >
> > > > > > > Agree with that, updated.
> > > > > > >
> > > > > > > >6006. RLMM.onPartitionLeadershipChanges(): This may be ok.
> > However,
> > > > > is it
> > > > > > > ture that other than the metadata topic, RLMM just needs to
> know
> > > > > whether
> > > > > > > there is a replica assigned to this broker and doesn't need to
> > know
> > > > > whether
> > > > > > > the replica is the leader or the follower?
> > > > > > >
> > > > > > > That may be true. If the implementation does not need that, it
> > can
> > > > > > > ignore the information in the callback.
> > > > > > >
> > > > > > > >6007: "Handle expired remote segments (leader and follower)":
> > Why is
> > > > > this
> > > > > > > needed in both the leader and the follower?
> > > > > > >
> > > > > > > Updated.
> > > > > > >
> > > > > > > >6008.       "name": "SegmentSizeInBytes",
> > > > > > >                 "type": "int64",
> > > > > > > The segment size can just be int32.
> > > > > > >
> > > > > > > Updated.
> > > > > > >
> > > > > > > >6009. For the record format in the log, it seems that we need
> > to add
> > > > > > > record
> > > > > > > type and record version before the serialized bytes. We can
> > follow
> > > > the
> > > > > > > convention used in
> > > > > > >
> > > > > > >
> > > > >
> > > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-631%3A+The+Quorum-based+Kafka+Controller#KIP631:TheQuorumbasedKafkaController-RecordFormats
> > > > > > >
> > > > > > > Yes, KIP already mentions that these are serialized before the
> > > > payload
> > > > > > > as below. We will mention explicitly that these two are written
> > > > before
> > > > > > > the data is written.
> > > > > > >
> > > > > > > RLMM instance on broker publishes the message to the topic with
> > key
> > > > as
> > > > > > > null and value with the below format.
> > > > > > >
> > > > > > > type      : unsigned var int, represents the value type. This
> > value
> > > > is
> > > > > > > 'apikey' as mentioned in the schema.
> > > > > > > version : unsigned var int, the 'version' number of the type as
> > > > > > > mentioned in the schema.
> > > > > > > data      : record payload in kafka protocol message format.
> > > > > > >
> > > > > > >
> > > > > > > >6010. remote.log.manager.thread.pool.size: The default value
> is
> > 10.
> > > > > This
> > > > > > > might be too high when enabling the tiered feature for the
> first
> > > > time.
> > > > > > > Since there are lots of segments that need to be tiered
> > initially, a
> > > > > large
> > > > > > > number of threads could overwhelm the broker.
> > > > > > >
> > > > > > > Is the default value 5 reasonable?
> > > > > > >
> > > > > > > 6011. "The number of milli seconds to keep the local log
> segment
> > > > > before it
> > > > > > > gets deleted. If not set, the value in `log.retention.minutes`
> is
> > > > > used. If
> > > > > > > set to -1, no time limit is applied." We should use
> > log.retention.ms
> > > > > > > instead of log.retention.minutes.
> > > > > > > Nice typo catch. Updated the KIP.
> > > > > > >
> > > > > > > Thanks,
> > > > > > > Satish.
> > > > > > >
> > > > > > > On Thu, Dec 3, 2020 at 8:03 AM Jun Rao <ju...@confluent.io>
> wrote:
> > > > > > > >
> > > > > > > > Hi, Satish,
> > > > > > > >
> > > > > > > > Thanks for the updated KIP. A few more comments below.
> > > > > > > >
> > > > > > > > 605.2 It's rare for the follower to need the remote data. So,
> > the
> > > > > current
> > > > > > > > approach is fine too. Could you document the process of
> > rebuilding
> > > > > the
> > > > > > > > producer state since we can't simply trim the producerState
> to
> > an
> > > > > offset
> > > > > > > in
> > > > > > > > the middle of a segment.
> > > > > > > >
> > > > > > > > 5102.2 Would it be clearer to make startPosiont long and
> > > > endPosition
> > > > > of
> > > > > > > > Optional<Long>?
> > > > > > > >
> > > > > > > > 5102.5 LogSegmentData still has leaderEpochIndex as File
> > instead of
> > > > > > > > ByteBuffer.
> > > > > > > >
> > > > > > > > 5102.7 Could you define all public methods for
> LogSegmentData?
> > > > > > > >
> > > > > > > > 5103.5 Could you change the reference to
> > rlm_process_interval_ms
> > > > and
> > > > > > > > rlm_retry_interval_ms to the new config names? Also, the
> retry
> > > > > interval
> > > > > > > > config seems still missing. It would be useful to support
> > > > exponential
> > > > > > > > backoff with the retry interval config.
> > > > > > > >
> > > > > > > > 5111. "RLM follower fetches the earliest offset for the
> > earliest
> > > > > leader
> > > > > > > > epoch by calling RLMM.earliestLogOffset(TopicPartition
> > > > > topicPartition,
> > > > > > > int
> > > > > > > > leaderEpoch) and updates that as the log start offset." This
> > text
> > > > is
> > > > > > > still
> > > > > > > > there. Also, could we remove earliestLogOffset() from RLMM?
> > > > > > > >
> > > > > > > > 5115. There are still references to "remote log cleaners".
> > > > > > > >
> > > > > > > > 6000. Since we are returning new error codes, we need to bump
> > up
> > > > the
> > > > > > > > protocol version for Fetch request. Also, it will be useful
> to
> > > > > document
> > > > > > > all
> > > > > > > > new error codes and whether they are retriable or not.
> > > > > > > >
> > > > > > > > 6001. public Map<Long, Long> segmentLeaderEpochs():
> Currently,
> > > > > > > leaderEpoch
> > > > > > > > is int32 instead of long.
> > > > > > > >
> > > > > > > > 6002. Is RemoteLogSegmentMetadata.markedForDeletion() needed
> > given
> > > > > > > > RemoteLogSegmentMetadata.state()?
> > > > > > > >
> > > > > > > > 6003. RemoteLogSegmentMetadata
> > > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > topicPartition, long offset, int epochForOffset): Should this
> > > > return
> > > > > > > > Optional<RemoteLogSegmentMetadata>?
> > > > > > > >
> > > > > > > > 6004. DeletePartitionUpdate.epoch(): It would be useful to
> > pick a
> > > > > more
> > > > > > > > indicative name so that people understand what epoch this is.
> > > > > > > >
> > > > > > > > 6005. RemoteLogState: It seems it's better to split it
> between
> > > > > > > > DeletePartitionUpdate and RemoteLogSegmentMetadataUpdate
> since
> > the
> > > > > states
> > > > > > > > are never shared between the two use cases.
> > > > > > > >
> > > > > > > > 6006. RLMM.onPartitionLeadershipChanges(): This may be ok.
> > However,
> > > > > is it
> > > > > > > > ture that other than the metadata topic, RLMM just needs to
> > know
> > > > > whether
> > > > > > > > there is a replica assigned to this broker and doesn't need
> to
> > know
> > > > > > > whether
> > > > > > > > the replica is the leader or the follower?
> > > > > > > >
> > > > > > > > 6007: "Handle expired remote segments (leader and follower)":
> > Why
> > > > is
> > > > > this
> > > > > > > > needed in both the leader and the follower?
> > > > > > > >
> > > > > > > > 6008.       "name": "SegmentSizeInBytes",
> > > > > > > >                 "type": "int64",
> > > > > > > > The segment size can just be int32.
> > > > > > > >
> > > > > > > > 6009. For the record format in the log, it seems that we need
> > to
> > > > add
> > > > > > > record
> > > > > > > > type and record version before the serialized bytes. We can
> > follow
> > > > > the
> > > > > > > > convention used in
> > > > > > > >
> > > > > > >
> > > > >
> > > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-631%3A+The+Quorum-based+Kafka+Controller#KIP631:TheQuorumbasedKafkaController-RecordFormats
> > > > > > > > .
> > > > > > > >
> > > > > > > > 6010. remote.log.manager.thread.pool.size: The default value
> > is 10.
> > > > > This
> > > > > > > > might be too high when enabling the tiered feature for the
> > first
> > > > > time.
> > > > > > > > Since there are lots of segments that need to be tiered
> > initially,
> > > > a
> > > > > > > large
> > > > > > > > number of threads could overwhelm the broker.
> > > > > > > >
> > > > > > > > 6011. "The number of milli seconds to keep the local log
> > segment
> > > > > before
> > > > > > > it
> > > > > > > > gets deleted. If not set, the value in
> `log.retention.minutes`
> > is
> > > > > used.
> > > > > > > If
> > > > > > > > set to -1, no time limit is applied." We should use
> > > > log.retention.ms
> > > > > > > > instead of log.retention.minutes.
> > > > > > > >
> > > > > > > > Jun
> > > > > > > >
> > > > > > > > On Tue, Dec 1, 2020 at 2:42 AM Satish Duggana <
> > > > > satish.duggana@gmail.com>
> > > > > > > > wrote:
> > > > > > > >
> > > > > > > > > Hi,
> > > > > > > > > We updated the KIP with the points mentioned in the earlier
> > mail
> > > > > > > > > except for KIP-516 related changes. You can go through them
> > and
> > > > > let us
> > > > > > > > > know if you have any comments. We will update the KIP with
> > the
> > > > > > > > > remaining todo items and KIP-516 related changes by end of
> > this
> > > > > > > > > week(5th Dec).
> > > > > > > > >
> > > > > > > > > Thanks,
> > > > > > > > > Satish.
> > > > > > > > >
> > > > > > > > > On Tue, Nov 10, 2020 at 8:26 PM Satish Duggana <
> > > > > > > satish.duggana@gmail.com>
> > > > > > > > > wrote:
> > > > > > > > > >
> > > > > > > > > > Hi Jun,
> > > > > > > > > > Thanks for your comments. Please find the inline replies
> > below.
> > > > > > > > > >
> > > > > > > > > > 605.2 "Build the local leader epoch cache by cutting the
> > leader
> > > > > epoch
> > > > > > > > > > sequence received from remote storage to [LSO, ELO]." I
> > > > > mentioned an
> > > > > > > > > issue
> > > > > > > > > > earlier. Suppose the leader's local start offset is 100.
> > The
> > > > > follower
> > > > > > > > > finds
> > > > > > > > > > a remote segment covering offset range [80, 120). The
> > > > > producerState
> > > > > > > with
> > > > > > > > > > this remote segment is up to offset 120. To trim the
> > > > > producerState to
> > > > > > > > > > offset 100 requires more work since one needs to download
> > the
> > > > > > > previous
> > > > > > > > > > producerState up to offset 80 and then replay the
> messages
> > from
> > > > > 80 to
> > > > > > > > > 100.
> > > > > > > > > > It seems that it's simpler in this case for the follower
> > just
> > > > to
> > > > > > > take the
> > > > > > > > > > remote segment as it is and start fetching from offset
> 120.
> > > > > > > > > >
> > > > > > > > > > We chose that approach to avoid any edge cases here. It
> > may be
> > > > > > > > > > possible that the remote log segment that is received may
> > not
> > > > > have
> > > > > > > the
> > > > > > > > > > same leader epoch sequence from 100-120 as it contains on
> > the
> > > > > > > > > > leader(this can happen due to unclean leader). It is safe
> > to
> > > > > start
> > > > > > > > > > from what the leader returns here.Another way is to find
> > the
> > > > > remote
> > > > > > > > > > log segment
> > > > > > > > > >
> > > > > > > > > > 5016. Just to echo what Kowshik was saying. It seems that
> > > > > > > > > > RLMM.onPartitionLeadershipChanges() is only called on the
> > > > > replicas
> > > > > > > for a
> > > > > > > > > > partition, not on the replicas for the
> > > > > __remote_log_segment_metadata
> > > > > > > > > > partition. It's not clear how the leader of
> > > > > > > __remote_log_segment_metadata
> > > > > > > > > > obtains the metadata for remote segments for deletion.
> > > > > > > > > >
> > > > > > > > > > RLMM will always receive the callback for the remote log
> > > > metadata
> > > > > > > > > > topic partitions hosted on the local broker and these
> will
> > be
> > > > > > > > > > subscribed. I will make this clear in the KIP.
> > > > > > > > > >
> > > > > > > > > > 5100. KIP-516 has been accepted and is being implemented
> > now.
> > > > > Could
> > > > > > > you
> > > > > > > > > > update the KIP based on topicID?
> > > > > > > > > >
> > > > > > > > > > We mentioned KIP-516 and how it helps. We will update
> this
> > KIP
> > > > > with
> > > > > > > > > > all the changes it brings with KIP-516.
> > > > > > > > > >
> > > > > > > > > > 5101. RLMM: It would be useful to clarify how the
> > following two
> > > > > APIs
> > > > > > > are
> > > > > > > > > > used. According to the wiki, the former is used for topic
> > > > > deletion
> > > > > > > and
> > > > > > > > > the
> > > > > > > > > > latter is used for retention. It seems that retention
> > should
> > > > use
> > > > > the
> > > > > > > > > former
> > > > > > > > > > since remote segments without a matching epoch in the
> > leader
> > > > > > > (potentially
> > > > > > > > > > due to unclean leader election) also need to be garbage
> > > > > collected.
> > > > > > > The
> > > > > > > > > > latter seems to be used for the new leader to determine
> the
> > > > last
> > > > > > > tiered
> > > > > > > > > > segment.
> > > > > > > > > >     default Iterator<RemoteLogSegmentMetadata>
> > > > > > > > > > listRemoteLogSegments(TopicPartition topicPartition)
> > > > > > > > > >     Iterator<RemoteLogSegmentMetadata>
> > > > > > > > > listRemoteLogSegments(TopicPartition
> > > > > > > > > > topicPartition, long leaderEpoch);
> > > > > > > > > >
> > > > > > > > > > Right,.that is what we are currently doing. We will
> update
> > the
> > > > > > > > > > javadocs and wiki with that. Earlier, we did not want to
> > remove
> > > > > the
> > > > > > > > > > segments which are not matched with leader epochs from
> the
> > > > ladder
> > > > > > > > > > partition as they may be used later by a replica which
> can
> > > > > become a
> > > > > > > > > > leader (unclean leader election) and refer those
> segments.
> > But
> > > > > that
> > > > > > > > > > may leak these segments in remote storage until the topic
> > > > > lifetime.
> > > > > > > We
> > > > > > > > > > decided to cleanup the segments with the oldest incase of
> > size
> > > > > based
> > > > > > > > > > retention also.
> > > > > > > > > >
> > > > > > > > > > 5102. RSM:
> > > > > > > > > > 5102.1 For methods like fetchLogSegmentData(), it seems
> > that
> > > > > they can
> > > > > > > > > > use RemoteLogSegmentId instead of
> RemoteLogSegmentMetadata.
> > > > > > > > > >
> > > > > > > > > > It will be useful to have metadata for RSM to fetch log
> > > > segment.
> > > > > It
> > > > > > > > > > may create location/path using id with other metadata
> too.
> > > > > > > > > >
> > > > > > > > > > 5102.2 In fetchLogSegmentData(), should we use long
> > instead of
> > > > > Long?
> > > > > > > > > >
> > > > > > > > > > Wanted to keep endPosition as optional to read till the
> > end of
> > > > > the
> > > > > > > > > > segment and avoid sentinels.
> > > > > > > > > >
> > > > > > > > > > 5102.3 Why only some of the methods have default
> > implementation
> > > > > and
> > > > > > > > > others
> > > > > > > > > > Don't?
> > > > > > > > > >
> > > > > > > > > > Actually,  RSM will not have any default implementations.
> > > > Those 3
> > > > > > > > > > methods were made default earlier for tests etc. Updated
> > the
> > > > > wiki.
> > > > > > > > > >
> > > > > > > > > > 5102.4. Could we define RemoteLogSegmentMetadataUpdate
> > > > > > > > > > and DeletePartitionUpdate?
> > > > > > > > > >
> > > > > > > > > > Sure, they will be added.
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > 5102.5 LogSegmentData: It seems that it's easier to pass
> > > > > > > > > > in leaderEpochIndex as a ByteBuffer or byte array than a
> > file
> > > > > since
> > > > > > > it
> > > > > > > > > will
> > > > > > > > > > be generated in memory.
> > > > > > > > > >
> > > > > > > > > > Right, this is in plan.
> > > > > > > > > >
> > > > > > > > > > 5102.6 RemoteLogSegmentMetadata: It seems that it needs
> > both
> > > > > > > baseOffset
> > > > > > > > > and
> > > > > > > > > > startOffset. For example, deleteRecords() could move the
> > > > > startOffset
> > > > > > > to
> > > > > > > > > the
> > > > > > > > > > middle of a segment. If we copy the full segment to
> remote
> > > > > storage,
> > > > > > > the
> > > > > > > > > > baseOffset and the startOffset will be different.
> > > > > > > > > >
> > > > > > > > > > Good point. startOffset is baseOffset by default, if not
> > set
> > > > > > > explicitly.
> > > > > > > > > >
> > > > > > > > > > 5102.7 Could we define all the public methods for
> > > > > > > > > RemoteLogSegmentMetadata
> > > > > > > > > > and LogSegmentData?
> > > > > > > > > >
> > > > > > > > > > Sure, updated the wiki.
> > > > > > > > > >
> > > > > > > > > > 5102.8 Could we document whether endOffset in
> > > > > > > RemoteLogSegmentMetadata is
> > > > > > > > > > inclusive/exclusive?
> > > > > > > > > >
> > > > > > > > > > It is inclusive, will update.
> > > > > > > > > >
> > > > > > > > > > 5103. configs:
> > > > > > > > > > 5103.1 Could we define the default value of non-required
> > > > configs
> > > > > > > (e.g the
> > > > > > > > > > size of new thread pools)?
> > > > > > > > > >
> > > > > > > > > > Sure, that makes sense.
> > > > > > > > > >
> > > > > > > > > > 5103.2 It seems that local.log.retention.ms should
> > default to
> > > > > > > > > retention.ms,
> > > > > > > > > > instead of remote.log.retention.minutes. Similarly, it
> > seems
> > > > > > > > > > that local.log.retention.bytes should default to
> > segment.bytes.
> > > > > > > > > >
> > > > > > > > > > Right, we do not have  remote.log.retention as we
> discussed
> > > > > earlier.
> > > > > > > > > > Thanks for catching the typo.
> > > > > > > > > >
> > > > > > > > > > 5103.3 remote.log.manager.thread.pool.size: The
> description
> > > > says
> > > > > > > "used in
> > > > > > > > > > scheduling tasks to copy segments, fetch remote log
> > indexes and
> > > > > > > clean up
> > > > > > > > > > remote log segments". However, there is a separate
> > > > > > > > > > config remote.log.reader.threads for fetching remote
> data.
> > It's
> > > > > > > weird to
> > > > > > > > > > fetch remote index and log in different thread pools
> since
> > both
> > > > > are
> > > > > > > used
> > > > > > > > > > for serving fetch requests.
> > > > > > > > > >
> > > > > > > > > > Right, remote.log.manager.thread.pool is mainly used for
> > > > > copy/cleanup
> > > > > > > > > > activities. Fetch path always goes through
> > > > > remote.log.reader.threads.
> > > > > > > > > >
> > > > > > > > > > 5103.4 remote.log.manager.task.interval.ms: Is that the
> > amount
> > > > > of
> > > > > > > time
> > > > > > > > > to
> > > > > > > > > > back off when there is no work to do? If so, perhaps it
> > can be
> > > > > > > renamed as
> > > > > > > > > > backoff.ms.
> > > > > > > > > >
> > > > > > > > > > This is the delay interval for each iteration. It may be
> > > > renamed
> > > > > to
> > > > > > > > > > remote.log.manager.task.delay.ms
> > > > > > > > > >
> > > > > > > > > > 5103.5 Are rlm_process_interval_ms and
> > rlm_retry_interval_ms
> > > > > > > configs? If
> > > > > > > > > > so, they need to be listed in this section.
> > > > > > > > > >
> > > > > > > > > > remote.log.manager.task.interval.ms is the process
> > internal,
> > > > > retry
> > > > > > > > > > interval is missing in the configs, which will be updated
> > in
> > > > the
> > > > > KIP.
> > > > > > > > > >
> > > > > > > > > > 5104. "RLM maintains a bounded cache(possibly LRU) of the
> > index
> > > > > > > files of
> > > > > > > > > > remote log segments to avoid multiple index fetches from
> > the
> > > > > remote
> > > > > > > > > > storage." Is the RLM in memory or on disk? If on disk,
> > where is
> > > > > it
> > > > > > > > > stored?
> > > > > > > > > > Do we need a configuration to bound the size?
> > > > > > > > > >
> > > > > > > > > > It is stored on disk. They are stored in a directory
> > > > > > > > > > `remote-log-index-cache` under log dir. We plan to have a
> > > > config
> > > > > for
> > > > > > > > > > that instead of default. We will have a configuration for
> > that.
> > > > > > > > > >
> > > > > > > > > > 5105. The KIP uses local-log-start-offset and Earliest
> > Local
> > > > > Offset
> > > > > > > in
> > > > > > > > > > different places. It would be useful to standardize the
> > > > > terminology.
> > > > > > > > > >
> > > > > > > > > > Sure.
> > > > > > > > > >
> > > > > > > > > > 5106. The section on "In BuildingRemoteLogAux state". It
> > listed
> > > > > two
> > > > > > > > > options
> > > > > > > > > > without saying which option is chosen.
> > > > > > > > > > We already mentioned in the KIP that we chose option-2.
> > > > > > > > > >
> > > > > > > > > > 5107. Follower to leader transition: It has step 2, but
> not
> > > > step
> > > > > 1.
> > > > > > > > > > Step-1 is there but it is not explicitly highlighted. It
> is
> > > > > previous
> > > > > > > > > > table to step-2.
> > > > > > > > > >
> > > > > > > > > > 5108. If a consumer fetches from the remote data and the
> > remote
> > > > > > > storage
> > > > > > > > > is
> > > > > > > > > > not available, what error code is used in the fetch
> > response?
> > > > > > > > > >
> > > > > > > > > > Good point. We have not yet defined the error for this
> > case. We
> > > > > need
> > > > > > > > > > to define an error message and send the same in fetch
> > response.
> > > > > > > > > >
> > > > > > > > > > 5109. "ListOffsets: For timestamps >= 0, it returns the
> > first
> > > > > message
> > > > > > > > > > offset whose timestamp is >= to the given timestamp in
> the
> > > > > request.
> > > > > > > That
> > > > > > > > > > means it checks in remote log time indexes first, after
> > which
> > > > > local
> > > > > > > log
> > > > > > > > > > time indexes are checked." Could you document which
> method
> > in
> > > > > RLMM is
> > > > > > > > > used
> > > > > > > > > > for this?
> > > > > > > > > >
> > > > > > > > > > Okay.
> > > > > > > > > >
> > > > > > > > > > 5110. Stopreplica: "it sets all the remote log segment
> > metadata
> > > > > of
> > > > > > > that
> > > > > > > > > > partition with a delete marker and publishes them to
> RLMM."
> > > > This
> > > > > > > seems
> > > > > > > > > > outdated given the new topic deletion logic.
> > > > > > > > > >
> > > > > > > > > > Will update with KIP-516 related points.
> > > > > > > > > >
> > > > > > > > > > 5111. "RLM follower fetches the earliest offset for the
> > > > earliest
> > > > > > > leader
> > > > > > > > > > epoch by calling RLMM.earliestLogOffset(TopicPartition
> > > > > > > topicPartition,
> > > > > > > > > int
> > > > > > > > > > leaderEpoch) and updates that as the log start offset."
> Do
> > we
> > > > > need
> > > > > > > that
> > > > > > > > > > since replication propagates logStartOffset already?
> > > > > > > > > >
> > > > > > > > > > Good point. Right, existing replication protocol takes
> > care of
> > > > > > > > > > updating the followers’s log start offset received from
> the
> > > > > leader.
> > > > > > > > > >
> > > > > > > > > > 5112. Is the default maxWaitMs of 500ms enough for
> fetching
> > > > from
> > > > > > > remote
> > > > > > > > > > storage?
> > > > > > > > > >
> > > > > > > > > > Remote reads may fail within the current default wait
> > time, but
> > > > > > > > > > subsequent fetches would be able to serve as that data is
> > > > stored
> > > > > in
> > > > > > > > > > the local cache. This cache is currently implemented in
> > RSMs.
> > > > > But we
> > > > > > > > > > plan to pull this into the remote log messaging layer in
> > > > future.
> > > > > > > > > >
> > > > > > > > > > 5113. "Committed offsets can be stored in a local file to
> > avoid
> > > > > > > reading
> > > > > > > > > the
> > > > > > > > > > messages again when a broker is restarted." Could you
> > describe
> > > > > the
> > > > > > > format
> > > > > > > > > > and the location of the file? Also, could the same
> message
> > be
> > > > > > > processed
> > > > > > > > > by
> > > > > > > > > > RLMM again after broker restart? If so, how do we handle
> > that?
> > > > > > > > > >
> > > > > > > > > > Sure, we will update in the KIP.
> > > > > > > > > >
> > > > > > > > > > 5114. Message format
> > > > > > > > > > 5114.1 There are two records named
> > > > RemoteLogSegmentMetadataRecord
> > > > > > > with
> > > > > > > > > > apiKey 0 and 1.
> > > > > > > > > >
> > > > > > > > > > Nice catch, that was a typo. Fixed in the wiki.
> > > > > > > > > >
> > > > > > > > > > 5114.2 RemoteLogSegmentMetadataRecord: Could we document
> > > > whether
> > > > > > > > > endOffset
> > > > > > > > > > is inclusive/exclusive?
> > > > > > > > > > It is inclusive, will update.
> > > > > > > > > >
> > > > > > > > > > 5114.3 RemoteLogSegmentMetadataRecord: Could you explain
> > > > > LeaderEpoch
> > > > > > > a
> > > > > > > > > bit
> > > > > > > > > > more? Is that the epoch of the leader when it copies the
> > > > segment
> > > > > to
> > > > > > > > > remote
> > > > > > > > > > storage? Also, how will this field be used?
> > > > > > > > > >
> > > > > > > > > > Right, this is the leader epoch of the broker which
> copied
> > this
> > > > > > > > > > segment. This is helpful in reason about which broker
> > copied
> > > > the
> > > > > > > > > > segment to remote storage.
> > > > > > > > > >
> > > > > > > > > > 5114.4 EventTimestamp: Could you explain this a bit more?
> > Each
> > > > > > > record in
> > > > > > > > > > Kafka already has a timestamp field. Could we just use
> > that?
> > > > > > > > > >
> > > > > > > > > > This is the  timestamp at which  the respective event
> > occurred.
> > > > > Added
> > > > > > > > > > this  to RemoteLogSegmentMetadata as RLMM can be  any
> other
> > > > > > > > > > implementation. We thought about that but it looked
> > cleaner to
> > > > > use at
> > > > > > > > > > the message structure level instead of getting that from
> > the
> > > > > consumer
> > > > > > > > > > record and using that to build the respective event.
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > 5114.5 SegmentSizeInBytes: Could this just be int32?
> > > > > > > > > >
> > > > > > > > > > Right, it looks like config allows only int value >= 14.
> > > > > > > > > >
> > > > > > > > > > 5115. RemoteLogCleaner(RLC): This could be confused with
> > the
> > > > log
> > > > > > > cleaner
> > > > > > > > > > for compaction. Perhaps it can be renamed to sth like
> > > > > > > > > > RemotePartitionRemover.
> > > > > > > > > >
> > > > > > > > > > I am fine with RemotePartitionRemover or
> > > > > RemoteLogDeletionManager(we
> > > > > > > > > > have other manager classes like RLM, RLMM).
> > > > > > > > > >
> > > > > > > > > > 5116. "RLC receives the delete_partition_marked and
> > processes
> > > > it
> > > > > if
> > > > > > > it is
> > > > > > > > > > not yet processed earlier." How does it know whether
> > > > > > > > > > delete_partition_marked has been processed earlier?
> > > > > > > > > >
> > > > > > > > > > This is to handle duplicate delete_partition_marked
> > events. RLC
> > > > > > > > > > internally maintains a state for the delete_partition
> > events
> > > > and
> > > > > if
> > > > > > > it
> > > > > > > > > > already has an existing event then it ignores if it is
> > already
> > > > > being
> > > > > > > > > > processed.
> > > > > > > > > >
> > > > > > > > > > 5117. Should we add a new MessageFormatter to read the
> tier
> > > > > metadata
> > > > > > > > > topic?
> > > > > > > > > >
> > > > > > > > > > Right, this is in plan but did not mention it in the KIP.
> > This
> > > > > will
> > > > > > > be
> > > > > > > > > > useful for debugging purposes too.
> > > > > > > > > >
> > > > > > > > > > 5118. "Maximum remote log reader thread pool task queue
> > size.
> > > > If
> > > > > the
> > > > > > > task
> > > > > > > > > > queue is full, broker will stop reading remote log
> > segments."
> > > > > What
> > > > > > > do we
> > > > > > > > > > return to the fetch request in this case?
> > > > > > > > > >
> > > > > > > > > > We return an error response for that partition.
> > > > > > > > > >
> > > > > > > > > > 5119. It would be useful to list all things not supported
> > in
> > > > the
> > > > > > > first
> > > > > > > > > > version in a Future work or Limitations section. For
> > example,
> > > > > > > compacted
> > > > > > > > > > topic, JBOD, changing remote.log.storage.enable from true
> > to
> > > > > false,
> > > > > > > etc.
> > > > > > > > > >
> > > > > > > > > > We already have a non-goals section which is filled with
> > some
> > > > of
> > > > > > > these
> > > > > > > > > > details. Do we need another limitations section?
> > > > > > > > > >
> > > > > > > > > > Thanks,
> > > > > > > > > > Satish.
> > > > > > > > > >
> > > > > > > > > > On Wed, Nov 4, 2020 at 11:27 PM Jun Rao <
> jun@confluent.io>
> > > > > wrote:
> > > > > > > > > > >
> > > > > > > > > > > Hi, Satish,
> > > > > > > > > > >
> > > > > > > > > > > Thanks for the updated KIP. A few more comments below.
> > > > > > > > > > >
> > > > > > > > > > > 605.2 "Build the local leader epoch cache by cutting
> the
> > > > leader
> > > > > > > epoch
> > > > > > > > > > > sequence received from remote storage to [LSO, ELO]." I
> > > > > mentioned
> > > > > > > an
> > > > > > > > > issue
> > > > > > > > > > > earlier. Suppose the leader's local start offset is
> 100.
> > The
> > > > > > > follower
> > > > > > > > > finds
> > > > > > > > > > > a remote segment covering offset range [80, 120). The
> > > > > producerState
> > > > > > > > > with
> > > > > > > > > > > this remote segment is up to offset 120. To trim the
> > > > > producerState
> > > > > > > to
> > > > > > > > > > > offset 100 requires more work since one needs to
> > download the
> > > > > > > previous
> > > > > > > > > > > producerState up to offset 80 and then replay the
> > messages
> > > > > from 80
> > > > > > > to
> > > > > > > > > 100.
> > > > > > > > > > > It seems that it's simpler in this case for the
> follower
> > just
> > > > > to
> > > > > > > take
> > > > > > > > > the
> > > > > > > > > > > remote segment as it is and start fetching from offset
> > 120.
> > > > > > > > > > >
> > > > > > > > > > > 5016. Just to echo what Kowshik was saying. It seems
> that
> > > > > > > > > > > RLMM.onPartitionLeadershipChanges() is only called on
> the
> > > > > replicas
> > > > > > > for
> > > > > > > > > a
> > > > > > > > > > > partition, not on the replicas for the
> > > > > > > __remote_log_segment_metadata
> > > > > > > > > > > partition. It's not clear how the leader of
> > > > > > > > > __remote_log_segment_metadata
> > > > > > > > > > > obtains the metadata for remote segments for deletion.
> > > > > > > > > > >
> > > > > > > > > > > 5100. KIP-516 has been accepted and is being
> implemented
> > now.
> > > > > > > Could you
> > > > > > > > > > > update the KIP based on topicID?
> > > > > > > > > > >
> > > > > > > > > > > 5101. RLMM: It would be useful to clarify how the
> > following
> > > > two
> > > > > > > APIs
> > > > > > > > > are
> > > > > > > > > > > used. According to the wiki, the former is used for
> topic
> > > > > deletion
> > > > > > > and
> > > > > > > > > the
> > > > > > > > > > > latter is used for retention. It seems that retention
> > should
> > > > > use
> > > > > > > the
> > > > > > > > > former
> > > > > > > > > > > since remote segments without a matching epoch in the
> > leader
> > > > > > > > > (potentially
> > > > > > > > > > > due to unclean leader election) also need to be garbage
> > > > > collected.
> > > > > > > The
> > > > > > > > > > > latter seems to be used for the new leader to determine
> > the
> > > > > last
> > > > > > > tiered
> > > > > > > > > > > segment.
> > > > > > > > > > >     default Iterator<RemoteLogSegmentMetadata>
> > > > > > > > > > > listRemoteLogSegments(TopicPartition topicPartition)
> > > > > > > > > > >     Iterator<RemoteLogSegmentMetadata>
> > > > > > > > > listRemoteLogSegments(TopicPartition
> > > > > > > > > > > topicPartition, long leaderEpoch);
> > > > > > > > > > >
> > > > > > > > > > > 5102. RSM:
> > > > > > > > > > > 5102.1 For methods like fetchLogSegmentData(), it seems
> > that
> > > > > they
> > > > > > > can
> > > > > > > > > > > use RemoteLogSegmentId instead of
> > RemoteLogSegmentMetadata.
> > > > > > > > > > > 5102.2 In fetchLogSegmentData(), should we use long
> > instead
> > > > of
> > > > > > > Long?
> > > > > > > > > > > 5102.3 Why only some of the methods have default
> > > > > implementation and
> > > > > > > > > others
> > > > > > > > > > > don't?
> > > > > > > > > > > 5102.4. Could we define RemoteLogSegmentMetadataUpdate
> > > > > > > > > > > and DeletePartitionUpdate?
> > > > > > > > > > > 5102.5 LogSegmentData: It seems that it's easier to
> pass
> > > > > > > > > > > in leaderEpochIndex as a ByteBuffer or byte array than
> a
> > file
> > > > > > > since it
> > > > > > > > > will
> > > > > > > > > > > be generated in memory.
> > > > > > > > > > > 5102.6 RemoteLogSegmentMetadata: It seems that it needs
> > both
> > > > > > > > > baseOffset and
> > > > > > > > > > > startOffset. For example, deleteRecords() could move
> the
> > > > > > > startOffset
> > > > > > > > > to the
> > > > > > > > > > > middle of a segment. If we copy the full segment to
> > remote
> > > > > > > storage, the
> > > > > > > > > > > baseOffset and the startOffset will be different.
> > > > > > > > > > > 5102.7 Could we define all the public methods for
> > > > > > > > > RemoteLogSegmentMetadata
> > > > > > > > > > > and LogSegmentData?
> > > > > > > > > > > 5102.8 Could we document whether endOffset in
> > > > > > > RemoteLogSegmentMetadata
> > > > > > > > > is
> > > > > > > > > > > inclusive/exclusive?
> > > > > > > > > > >
> > > > > > > > > > > 5103. configs:
> > > > > > > > > > > 5103.1 Could we define the default value of
> non-required
> > > > > configs
> > > > > > > (e.g
> > > > > > > > > the
> > > > > > > > > > > size of new thread pools)?
> > > > > > > > > > > 5103.2 It seems that local.log.retention.ms should
> > default
> > > > to
> > > > > > > > > retention.ms,
> > > > > > > > > > > instead of remote.log.retention.minutes. Similarly, it
> > seems
> > > > > > > > > > > that local.log.retention.bytes should default to
> > > > segment.bytes.
> > > > > > > > > > > 5103.3 remote.log.manager.thread.pool.size: The
> > description
> > > > > says
> > > > > > > "used
> > > > > > > > > in
> > > > > > > > > > > scheduling tasks to copy segments, fetch remote log
> > indexes
> > > > and
> > > > > > > clean
> > > > > > > > > up
> > > > > > > > > > > remote log segments". However, there is a separate
> > > > > > > > > > > config remote.log.reader.threads for fetching remote
> > data.
> > > > It's
> > > > > > > weird
> > > > > > > > > to
> > > > > > > > > > > fetch remote index and log in different thread pools
> > since
> > > > > both are
> > > > > > > > > used
> > > > > > > > > > > for serving fetch requests.
> > > > > > > > > > > 5103.4 remote.log.manager.task.interval.ms: Is that
> the
> > > > > amount of
> > > > > > > > > time to
> > > > > > > > > > > back off when there is no work to do? If so, perhaps it
> > can
> > > > be
> > > > > > > renamed
> > > > > > > > > as
> > > > > > > > > > > backoff.ms.
> > > > > > > > > > > 5103.5 Are rlm_process_interval_ms and
> > rlm_retry_interval_ms
> > > > > > > configs?
> > > > > > > > > If
> > > > > > > > > > > so, they need to be listed in this section.
> > > > > > > > > > >
> > > > > > > > > > > 5104. "RLM maintains a bounded cache(possibly LRU) of
> the
> > > > index
> > > > > > > files
> > > > > > > > > of
> > > > > > > > > > > remote log segments to avoid multiple index fetches
> from
> > the
> > > > > remote
> > > > > > > > > > > storage." Is the RLM in memory or on disk? If on disk,
> > where
> > > > > is it
> > > > > > > > > stored?
> > > > > > > > > > > Do we need a configuration to bound the size?
> > > > > > > > > > >
> > > > > > > > > > > 5105. The KIP uses local-log-start-offset and Earliest
> > Local
> > > > > > > Offset in
> > > > > > > > > > > different places. It would be useful to standardize the
> > > > > > > terminology.
> > > > > > > > > > >
> > > > > > > > > > > 5106. The section on "In BuildingRemoteLogAux state".
> It
> > > > > listed two
> > > > > > > > > options
> > > > > > > > > > > without saying which option is chosen.
> > > > > > > > > > >
> > > > > > > > > > > 5107. Follower to leader transition: It has step 2, but
> > not
> > > > > step 1.
> > > > > > > > > > >
> > > > > > > > > > > 5108. If a consumer fetches from the remote data and
> the
> > > > remote
> > > > > > > > > storage is
> > > > > > > > > > > not available, what error code is used in the fetch
> > response?
> > > > > > > > > > >
> > > > > > > > > > > 5109. "ListOffsets: For timestamps >= 0, it returns the
> > first
> > > > > > > message
> > > > > > > > > > > offset whose timestamp is >= to the given timestamp in
> > the
> > > > > request.
> > > > > > > > > That
> > > > > > > > > > > means it checks in remote log time indexes first, after
> > which
> > > > > > > local log
> > > > > > > > > > > time indexes are checked." Could you document which
> > method in
> > > > > RLMM
> > > > > > > is
> > > > > > > > > used
> > > > > > > > > > > for this?
> > > > > > > > > > >
> > > > > > > > > > > 5110. Stopreplica: "it sets all the remote log segment
> > > > > metadata of
> > > > > > > that
> > > > > > > > > > > partition with a delete marker and publishes them to
> > RLMM."
> > > > > This
> > > > > > > seems
> > > > > > > > > > > outdated given the new topic deletion logic.
> > > > > > > > > > >
> > > > > > > > > > > 5111. "RLM follower fetches the earliest offset for the
> > > > > earliest
> > > > > > > leader
> > > > > > > > > > > epoch by calling RLMM.earliestLogOffset(TopicPartition
> > > > > > > topicPartition,
> > > > > > > > > int
> > > > > > > > > > > leaderEpoch) and updates that as the log start offset."
> > Do we
> > > > > need
> > > > > > > that
> > > > > > > > > > > since replication propagates logStartOffset already?
> > > > > > > > > > >
> > > > > > > > > > > 5112. Is the default maxWaitMs of 500ms enough for
> > fetching
> > > > > from
> > > > > > > remote
> > > > > > > > > > > storage?
> > > > > > > > > > >
> > > > > > > > > > > 5113. "Committed offsets can be stored in a local file
> to
> > > > avoid
> > > > > > > > > reading the
> > > > > > > > > > > messages again when a broker is restarted." Could you
> > > > describe
> > > > > the
> > > > > > > > > format
> > > > > > > > > > > and the location of the file? Also, could the same
> > message be
> > > > > > > > > processed by
> > > > > > > > > > > RLMM again after broker restart? If so, how do we
> handle
> > > > that?
> > > > > > > > > > >
> > > > > > > > > > > 5114. Message format
> > > > > > > > > > > 5114.1 There are two records named
> > > > > RemoteLogSegmentMetadataRecord
> > > > > > > with
> > > > > > > > > > > apiKey 0 and 1.
> > > > > > > > > > > 5114.2 RemoteLogSegmentMetadataRecord: Could we
> document
> > > > > whether
> > > > > > > > > endOffset
> > > > > > > > > > > is inclusive/exclusive?
> > > > > > > > > > > 5114.3 RemoteLogSegmentMetadataRecord: Could you
> explain
> > > > > > > LeaderEpoch a
> > > > > > > > > bit
> > > > > > > > > > > more? Is that the epoch of the leader when it copies
> the
> > > > > segment to
> > > > > > > > > remote
> > > > > > > > > > > storage? Also, how will this field be used?
> > > > > > > > > > > 5114.4 EventTimestamp: Could you explain this a bit
> more?
> > > > Each
> > > > > > > record
> > > > > > > > > in
> > > > > > > > > > > Kafka already has a timestamp field. Could we just use
> > that?
> > > > > > > > > > > 5114.5 SegmentSizeInBytes: Could this just be int32?
> > > > > > > > > > >
> > > > > > > > > > > 5115. RemoteLogCleaner(RLC): This could be confused
> with
> > the
> > > > > log
> > > > > > > > > cleaner
> > > > > > > > > > > for compaction. Perhaps it can be renamed to sth like
> > > > > > > > > > > RemotePartitionRemover.
> > > > > > > > > > >
> > > > > > > > > > > 5116. "RLC receives the delete_partition_marked and
> > processes
> > > > > it
> > > > > > > if it
> > > > > > > > > is
> > > > > > > > > > > not yet processed earlier." How does it know whether
> > > > > > > > > > > delete_partition_marked has been processed earlier?
> > > > > > > > > > >
> > > > > > > > > > > 5117. Should we add a new MessageFormatter to read the
> > tier
> > > > > > > metadata
> > > > > > > > > topic?
> > > > > > > > > > >
> > > > > > > > > > > 5118. "Maximum remote log reader thread pool task queue
> > size.
> > > > > If
> > > > > > > the
> > > > > > > > > task
> > > > > > > > > > > queue is full, broker will stop reading remote log
> > segments."
> > > > > What
> > > > > > > do
> > > > > > > > > we
> > > > > > > > > > > return to the fetch request in this case?
> > > > > > > > > > >
> > > > > > > > > > > 5119. It would be useful to list all things not
> > supported in
> > > > > the
> > > > > > > first
> > > > > > > > > > > version in a Future work or Limitations section. For
> > example,
> > > > > > > compacted
> > > > > > > > > > > topic, JBOD, changing remote.log.storage.enable from
> > true to
> > > > > false,
> > > > > > > > > etc.
> > > > > > > > > > >
> > > > > > > > > > > Thanks,
> > > > > > > > > > >
> > > > > > > > > > > Jun
> > > > > > > > > > >
> > > > > > > > > > > On Tue, Oct 27, 2020 at 5:57 PM Kowshik Prakasam <
> > > > > > > > > kprakasam@confluent.io>
> > > > > > > > > > > wrote:
> > > > > > > > > > >
> > > > > > > > > > > > Hi Satish,
> > > > > > > > > > > >
> > > > > > > > > > > > Thanks for the updates to the KIP. Here are my first
> > batch
> > > > of
> > > > > > > > > > > > comments/suggestions on the latest version of the
> KIP.
> > > > > > > > > > > >
> > > > > > > > > > > > 5012. In the RemoteStorageManager interface, there is
> > an
> > > > API
> > > > > > > defined
> > > > > > > > > for
> > > > > > > > > > > > each file type. For example, fetchOffsetIndex,
> > > > > > > fetchTimestampIndex
> > > > > > > > > etc. To
> > > > > > > > > > > > avoid the duplication, I'd suggest we can instead
> have
> > a
> > > > > FileType
> > > > > > > > > enum and
> > > > > > > > > > > > a common get API based on the FileType.
> > > > > > > > > > > >
> > > > > > > > > > > > 5013. There are some references to the Google doc in
> > the
> > > > > KIP. I
> > > > > > > > > wasn't sure
> > > > > > > > > > > > if the Google doc is expected to be in sync with the
> > > > > contents of
> > > > > > > the
> > > > > > > > > wiki.
> > > > > > > > > > > > Going forward, it seems easier if just the KIP is
> > > > maintained
> > > > > as
> > > > > > > the
> > > > > > > > > source
> > > > > > > > > > > > of truth. In this regard, could you please move all
> the
> > > > > > > references
> > > > > > > > > to the
> > > > > > > > > > > > Google doc, maybe to a separate References section at
> > the
> > > > > bottom
> > > > > > > of
> > > > > > > > > the
> > > > > > > > > > > > KIP?
> > > > > > > > > > > >
> > > > > > > > > > > > 5014. There are some TODO sections in the KIP. Would
> > these
> > > > be
> > > > > > > filled
> > > > > > > > > up in
> > > > > > > > > > > > future iterations?
> > > > > > > > > > > >
> > > > > > > > > > > > 5015. Under "Topic deletion lifecycle", I'm trying to
> > > > > understand
> > > > > > > why
> > > > > > > > > do we
> > > > > > > > > > > > need delete_partition_marked as well as the
> > > > > > > delete_partition_started
> > > > > > > > > > > > messages. I couldn't spot a drawback if supposing we
> > > > > simplified
> > > > > > > the
> > > > > > > > > design
> > > > > > > > > > > > such that the controller would only write
> > > > > > > delete_partition_started
> > > > > > > > > message,
> > > > > > > > > > > > and RemoteLogCleaner (RLC) instance picks it up for
> > > > > processing.
> > > > > > > What
> > > > > > > > > am I
> > > > > > > > > > > > missing?
> > > > > > > > > > > >
> > > > > > > > > > > > 5016. Under "Topic deletion lifecycle", step (4) is
> > > > > mentioned as
> > > > > > > > > "RLC gets
> > > > > > > > > > > > all the remote log segments for the partition and
> each
> > of
> > > > > these
> > > > > > > > > remote log
> > > > > > > > > > > > segments is deleted with the next steps.". Since the
> > RLC
> > > > > instance
> > > > > > > > > runs on
> > > > > > > > > > > > each tier topic partition leader, how does the RLC
> > then get
> > > > > the
> > > > > > > list
> > > > > > > > > of
> > > > > > > > > > > > remote log segments to be deleted? It will be useful
> > to add
> > > > > that
> > > > > > > > > detail to
> > > > > > > > > > > > the KIP.
> > > > > > > > > > > >
> > > > > > > > > > > > 5017. Under "Public Interfaces -> Configs", there is
> a
> > line
> > > > > > > > > mentioning "We
> > > > > > > > > > > > will support flipping remote.log.storage.enable in
> next
> > > > > > > versions."
> > > > > > > > > It will
> > > > > > > > > > > > be useful to mention this in the "Future Work"
> section
> > of
> > > > > the KIP
> > > > > > > > > too.
> > > > > > > > > > > >
> > > > > > > > > > > > 5018. The KIP introduces a number of configuration
> > > > > parameters. It
> > > > > > > > > will be
> > > > > > > > > > > > useful to mention in the KIP if the user should
> assume
> > > > these
> > > > > as
> > > > > > > > > static
> > > > > > > > > > > > configuration in the server.properties file, or
> dynamic
> > > > > > > > > configuration which
> > > > > > > > > > > > can be modified without restarting the broker.
> > > > > > > > > > > >
> > > > > > > > > > > > 5019.  Maybe this is planned as a future update to
> the
> > KIP,
> > > > > but I
> > > > > > > > > thought
> > > > > > > > > > > > I'd mention it here. Could you please add details to
> > the
> > > > KIP
> > > > > on
> > > > > > > why
> > > > > > > > > RocksDB
> > > > > > > > > > > > was chosen as the default cache implementation of
> > RLMM, and
> > > > > how
> > > > > > > it
> > > > > > > > > is going
> > > > > > > > > > > > to be used? Were alternatives compared/considered?
> For
> > > > > example,
> > > > > > > it
> > > > > > > > > would be
> > > > > > > > > > > > useful to explain/evaluate the following: 1)
> > debuggability
> > > > > of the
> > > > > > > > > RocksDB
> > > > > > > > > > > > JNI interface, 2) performance, 3) portability across
> > > > > platforms
> > > > > > > and 4)
> > > > > > > > > > > > interface parity of RocksDB’s JNI api with it's
> > underlying
> > > > > C/C++
> > > > > > > api.
> > > > > > > > > > > >
> > > > > > > > > > > > 5020. Following up on (5019), for the RocksDB cache,
> it
> > > > will
> > > > > be
> > > > > > > > > useful to
> > > > > > > > > > > > explain the relationship/mapping between the
> following
> > in
> > > > the
> > > > > > > KIP:
> > > > > > > > > 1) # of
> > > > > > > > > > > > tiered partitions, 2) # of partitions of metadata
> topic
> > > > > > > > > > > > __remote_log_metadata and 3) # of RocksDB instances.
> > i.e.
> > > > is
> > > > > the
> > > > > > > > > plan to
> > > > > > > > > > > > have a RocksDB instance per tiered partition, or per
> > > > metadata
> > > > > > > topic
> > > > > > > > > > > > partition, or just 1 for per broker?
> > > > > > > > > > > >
> > > > > > > > > > > > 5021. I was looking at the implementation prototype
> (PR
> > > > link:
> > > > > > > > > > > > https://github.com/apache/kafka/pull/7561). It seems
> > that
> > > > a
> > > > > > > boolean
> > > > > > > > > > > > attribute is being introduced into the Log layer to
> > check
> > > > if
> > > > > > > remote
> > > > > > > > > log
> > > > > > > > > > > > capability is enabled. While the boolean footprint is
> > small
> > > > > at
> > > > > > > the
> > > > > > > > > moment,
> > > > > > > > > > > > this can easily grow in the future and become harder
> to
> > > > > > > > > > > > test/maintain, considering that the Log layer is
> > already
> > > > > pretty
> > > > > > > > > complex. We
> > > > > > > > > > > > should start thinking about how to manage such
> changes
> > to
> > > > > the Log
> > > > > > > > > layer
> > > > > > > > > > > > (for the purpose of improved testability, better
> > separation
> > > > > of
> > > > > > > > > concerns and
> > > > > > > > > > > > readability). One proposal I have is to take a step
> > back
> > > > and
> > > > > > > define a
> > > > > > > > > > > > higher level Log interface. Then, the Broker code can
> > be
> > > > > changed
> > > > > > > to
> > > > > > > > > use
> > > > > > > > > > > > this interface. It can be changed such that only a
> > handle
> > > > to
> > > > > the
> > > > > > > > > interface
> > > > > > > > > > > > is exposed to other components (such as LogCleaner,
> > > > > > > ReplicaManager
> > > > > > > > > etc.)
> > > > > > > > > > > > and not the underlying Log object. This approach
> keeps
> > the
> > > > > user
> > > > > > > of
> > > > > > > > > the Log
> > > > > > > > > > > > layer agnostic of the whereabouts of the data.
> > Underneath
> > > > the
> > > > > > > > > interface,
> > > > > > > > > > > > the implementing classes can completely separate
> local
> > log
> > > > > > > > > capabilities
> > > > > > > > > > > > from the remote log. For example, the Log class can
> be
> > > > > > > simplified to
> > > > > > > > > only
> > > > > > > > > > > > manage logic surrounding local log segments and
> > metadata.
> > > > > > > > > Additionally, a
> > > > > > > > > > > > wrapper class can be provided (implementing the
> higher
> > > > level
> > > > > Log
> > > > > > > > > interface)
> > > > > > > > > > > > which will contain any/all logic surrounding tiered
> > data.
> > > > The
> > > > > > > wrapper
> > > > > > > > > > > > class will wrap around an instance of the Log class
> > > > > delegating
> > > > > > > the
> > > > > > > > > local
> > > > > > > > > > > > log logic to it. Finally, a handle to the wrapper
> > class can
> > > > > be
> > > > > > > > > exposed to
> > > > > > > > > > > > the other components wherever they need a handle to
> the
> > > > > higher
> > > > > > > level
> > > > > > > > > Log
> > > > > > > > > > > > interface.
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > Cheers,
> > > > > > > > > > > > Kowshik
> > > > > > > > > > > >
> > > > > > > > > > > > On Mon, Oct 26, 2020 at 9:52 PM Satish Duggana <
> > > > > > > > > satish.duggana@gmail.com>
> > > > > > > > > > > > wrote:
> > > > > > > > > > > >
> > > > > > > > > > > > > Hi,
> > > > > > > > > > > > > KIP is updated with 1) topic deletion lifecycle and
> > its
> > > > > related
> > > > > > > > > items
> > > > > > > > > > > > > 2) Protocol changes(mainly related to ListOffsets)
> > and
> > > > > other
> > > > > > > minor
> > > > > > > > > > > > > changes.
> > > > > > > > > > > > > Please go through them and let us know your
> comments.
> > > > > > > > > > > > >
> > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > Satish.
> > > > > > > > > > > > >
> > > > > > > > > > > > > On Mon, Sep 28, 2020 at 9:10 PM Satish Duggana <
> > > > > > > > > satish.duggana@gmail.com
> > > > > > > > > > > > >
> > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Hi Dhruvil,
> > > > > > > > > > > > > > Thanks for looking into the KIP and sending your
> > > > > comments.
> > > > > > > Sorry
> > > > > > > > > for
> > > > > > > > > > > > > > the late reply, missed it in the mail thread.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 1. Could you describe how retention would work
> with
> > > > this
> > > > > KIP
> > > > > > > and
> > > > > > > > > which
> > > > > > > > > > > > > > threads are responsible for driving this work? I
> > > > believe
> > > > > > > there
> > > > > > > > > are 3
> > > > > > > > > > > > > kinds
> > > > > > > > > > > > > > of retention processes we are looking at:
> > > > > > > > > > > > > >   (a) Regular retention for data in tiered
> storage
> > as
> > > > per
> > > > > > > > > configured `
> > > > > > > > > > > > > > retention.ms` / `retention.bytes`.
> > > > > > > > > > > > > >   (b) Local retention for data in local storage
> as
> > per
> > > > > > > > > configured `
> > > > > > > > > > > > > > local.log.retention.ms` /
> > `local.log.retention.bytes`
> > > > > > > > > > > > > >   (c) Possibly regular retention for data in
> local
> > > > > storage,
> > > > > > > if
> > > > > > > > > the
> > > > > > > > > > > > > tiering
> > > > > > > > > > > > > > task is lagging or for data that is below the log
> > start
> > > > > > > offset.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Local log retention is done by the existing log
> > cleanup
> > > > > > > tasks.
> > > > > > > > > These
> > > > > > > > > > > > > > are not done for segments that are not yet copied
> > to
> > > > > remote
> > > > > > > > > storage.
> > > > > > > > > > > > > > Remote log cleanup is done by the leader
> > partition’s
> > > > > RLMTask.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 2. When does a segment become eligible to be
> > tiered? Is
> > > > > it as
> > > > > > > > > soon as
> > > > > > > > > > > > the
> > > > > > > > > > > > > > segment is rolled and the end offset is less than
> > the
> > > > > last
> > > > > > > stable
> > > > > > > > > > > > offset
> > > > > > > > > > > > > as
> > > > > > > > > > > > > > mentioned in the KIP? I wonder if we need to
> > consider
> > > > > other
> > > > > > > > > parameters
> > > > > > > > > > > > > too,
> > > > > > > > > > > > > > like the highwatermark so that we are guaranteed
> > that
> > > > > what
> > > > > > > we are
> > > > > > > > > > > > tiering
> > > > > > > > > > > > > > has been committed to the log and accepted by the
> > ISR.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > AFAIK, last stable offset is always <=
> > highwatermark.
> > > > > This
> > > > > > > will
> > > > > > > > > make
> > > > > > > > > > > > > > sure we are always tiering the message segments
> > which
> > > > > have
> > > > > > > been
> > > > > > > > > > > > > > accepted by ISR and transactionally completed.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 3. The section on "Follower Fetch Scenarios" is
> > useful
> > > > > but
> > > > > > > is a
> > > > > > > > > bit
> > > > > > > > > > > > > > difficult to parse at the moment. It would be
> > useful to
> > > > > > > > > summarize the
> > > > > > > > > > > > > > changes we need in the ReplicaFetcher.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > It may become difficult for users to read/follow
> > if we
> > > > > add
> > > > > > > code
> > > > > > > > > changes
> > > > > > > > > > > > > here.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 4. Related to the above, it's a bit unclear how
> we
> > are
> > > > > > > planning
> > > > > > > > > on
> > > > > > > > > > > > > > restoring the producer state for a new replica.
> > Could
> > > > you
> > > > > > > expand
> > > > > > > > > on
> > > > > > > > > > > > that?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > It is mentioned in the KIP
> > BuildingRemoteLogAuxState is
> > > > > > > > > introduced to
> > > > > > > > > > > > > > build the state like leader epoch sequence and
> > producer
> > > > > > > snapshots
> > > > > > > > > > > > > > before it starts fetching the data from the
> > leader. We
> > > > > will
> > > > > > > make
> > > > > > > > > it
> > > > > > > > > > > > > > clear in the KIP.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5. Similarly, it would be worth summarizing the
> > > > behavior
> > > > > on
> > > > > > > > > unclean
> > > > > > > > > > > > > leader
> > > > > > > > > > > > > > election. There are several scenarios to consider
> > here:
> > > > > data
> > > > > > > > > loss from
> > > > > > > > > > > > > > local log, data loss from remote log, data loss
> > from
> > > > > metadata
> > > > > > > > > topic,
> > > > > > > > > > > > etc.
> > > > > > > > > > > > > > It's worth describing these in detail.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > We mentioned the cases about unclean leader
> > election in
> > > > > the
> > > > > > > > > follower
> > > > > > > > > > > > > > fetch scenarios.
> > > > > > > > > > > > > > If there are errors while fetching data from
> remote
> > > > > store or
> > > > > > > > > metadata
> > > > > > > > > > > > > > store, it will work the same way as it works with
> > local
> > > > > log.
> > > > > > > It
> > > > > > > > > > > > > > returns the error back to the caller. Please let
> us
> > > > know
> > > > > if
> > > > > > > I am
> > > > > > > > > > > > > > missing your point here.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 7. For a READ_COMMITTED FetchRequest, how do we
> > > > retrieve
> > > > > and
> > > > > > > > > return the
> > > > > > > > > > > > > > aborted transaction metadata?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > When a fetch for a remote log is accessed, we
> will
> > > > fetch
> > > > > > > aborted
> > > > > > > > > > > > > > transactions along with the segment if it is not
> > found
> > > > > in the
> > > > > > > > > local
> > > > > > > > > > > > > > index cache. This includes the case of
> transaction
> > > > index
> > > > > not
> > > > > > > > > existing
> > > > > > > > > > > > > > in the remote log segment. That means, the cache
> > entry
> > > > > can be
> > > > > > > > > empty or
> > > > > > > > > > > > > > have a list of aborted transactions.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 8. The `LogSegmentData` class assumes that we
> have
> > a
> > > > log
> > > > > > > segment,
> > > > > > > > > > > > offset
> > > > > > > > > > > > > > index, time index, transaction index, producer
> > snapshot
> > > > > and
> > > > > > > > > leader
> > > > > > > > > > > > epoch
> > > > > > > > > > > > > > index. How do we deal with cases where we do not
> > have
> > > > > one or
> > > > > > > > > more of
> > > > > > > > > > > > > these?
> > > > > > > > > > > > > > For example, we may not have a transaction index
> or
> > > > > producer
> > > > > > > > > snapshot
> > > > > > > > > > > > > for a
> > > > > > > > > > > > > > particular segment. The former is optional, and
> the
> > > > > latter is
> > > > > > > > > only kept
> > > > > > > > > > > > > for
> > > > > > > > > > > > > > up to the 3 latest segments.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > This is a good point,  we discussed this in the
> > last
> > > > > meeting.
> > > > > > > > > > > > > > Transaction index is optional and we will copy
> them
> > > > only
> > > > > if
> > > > > > > it
> > > > > > > > > exists.
> > > > > > > > > > > > > > We want to keep all the producer snapshots at
> each
> > log
> > > > > > > segment
> > > > > > > > > rolling
> > > > > > > > > > > > > > and they can be removed if the log copying is
> > > > successful
> > > > > and
> > > > > > > it
> > > > > > > > > still
> > > > > > > > > > > > > > maintains the existing latest 3 segments, We only
> > > > delete
> > > > > the
> > > > > > > > > producer
> > > > > > > > > > > > > > snapshots which have been copied to remote log
> > segments
> > > > > on
> > > > > > > > > leader.
> > > > > > > > > > > > > > Follower will keep the log segments beyond the
> > segments
> > > > > which
> > > > > > > > > have not
> > > > > > > > > > > > > > been copied to remote storage. We will update the
> > KIP
> > > > > with
> > > > > > > these
> > > > > > > > > > > > > > details.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > Satish.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > On Thu, Sep 17, 2020 at 1:47 AM Dhruvil Shah <
> > > > > > > > > dhruvil@confluent.io>
> > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Hi Satish, Harsha,
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Thanks for the KIP. Few questions below:
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 1. Could you describe how retention would work
> > with
> > > > > this
> > > > > > > KIP
> > > > > > > > > and
> > > > > > > > > > > > which
> > > > > > > > > > > > > > > threads are responsible for driving this work?
> I
> > > > > believe
> > > > > > > there
> > > > > > > > > are 3
> > > > > > > > > > > > > kinds
> > > > > > > > > > > > > > > of retention processes we are looking at:
> > > > > > > > > > > > > > >   (a) Regular retention for data in tiered
> > storage as
> > > > > per
> > > > > > > > > configured
> > > > > > > > > > > > `
> > > > > > > > > > > > > > > retention.ms` / `retention.bytes`.
> > > > > > > > > > > > > > >   (b) Local retention for data in local storage
> > as
> > > > per
> > > > > > > > > configured `
> > > > > > > > > > > > > > > local.log.retention.ms` /
> > > > `local.log.retention.bytes`
> > > > > > > > > > > > > > >   (c) Possibly regular retention for data in
> > local
> > > > > > > storage, if
> > > > > > > > > the
> > > > > > > > > > > > > tiering
> > > > > > > > > > > > > > > task is lagging or for data that is below the
> log
> > > > start
> > > > > > > offset.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 2. When does a segment become eligible to be
> > tiered?
> > > > > Is it
> > > > > > > as
> > > > > > > > > soon as
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > segment is rolled and the end offset is less
> > than the
> > > > > last
> > > > > > > > > stable
> > > > > > > > > > > > > offset as
> > > > > > > > > > > > > > > mentioned in the KIP? I wonder if we need to
> > consider
> > > > > other
> > > > > > > > > > > > parameters
> > > > > > > > > > > > > too,
> > > > > > > > > > > > > > > like the highwatermark so that we are
> guaranteed
> > that
> > > > > what
> > > > > > > we
> > > > > > > > > are
> > > > > > > > > > > > > tiering
> > > > > > > > > > > > > > > has been committed to the log and accepted by
> the
> > > > ISR.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 3. The section on "Follower Fetch Scenarios" is
> > > > useful
> > > > > but
> > > > > > > is
> > > > > > > > > a bit
> > > > > > > > > > > > > > > difficult to parse at the moment. It would be
> > useful
> > > > to
> > > > > > > > > summarize the
> > > > > > > > > > > > > > > changes we need in the ReplicaFetcher.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 4. Related to the above, it's a bit unclear how
> > we
> > > > are
> > > > > > > > > planning on
> > > > > > > > > > > > > > > restoring the producer state for a new replica.
> > Could
> > > > > you
> > > > > > > > > expand on
> > > > > > > > > > > > > that?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5. Similarly, it would be worth summarizing the
> > > > > behavior on
> > > > > > > > > unclean
> > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > election. There are several scenarios to
> consider
> > > > here:
> > > > > > > data
> > > > > > > > > loss
> > > > > > > > > > > > from
> > > > > > > > > > > > > > > local log, data loss from remote log, data loss
> > from
> > > > > > > metadata
> > > > > > > > > topic,
> > > > > > > > > > > > > etc.
> > > > > > > > > > > > > > > It's worth describing these in detail.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 6. It would be useful to add details about how
> we
> > > > plan
> > > > > on
> > > > > > > using
> > > > > > > > > > > > > RocksDB in
> > > > > > > > > > > > > > > the default implementation of
> > > > > `RemoteLogMetadataManager`.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 7. For a READ_COMMITTED FetchRequest, how do we
> > > > > retrieve
> > > > > > > and
> > > > > > > > > return
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > aborted transaction metadata?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 8. The `LogSegmentData` class assumes that we
> > have a
> > > > > log
> > > > > > > > > segment,
> > > > > > > > > > > > > offset
> > > > > > > > > > > > > > > index, time index, transaction index, producer
> > > > > snapshot and
> > > > > > > > > leader
> > > > > > > > > > > > > epoch
> > > > > > > > > > > > > > > index. How do we deal with cases where we do
> not
> > have
> > > > > one
> > > > > > > or
> > > > > > > > > more of
> > > > > > > > > > > > > these?
> > > > > > > > > > > > > > > For example, we may not have a transaction
> index
> > or
> > > > > > > producer
> > > > > > > > > snapshot
> > > > > > > > > > > > > for a
> > > > > > > > > > > > > > > particular segment. The former is optional, and
> > the
> > > > > latter
> > > > > > > is
> > > > > > > > > only
> > > > > > > > > > > > > kept for
> > > > > > > > > > > > > > > up to the 3 latest segments.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > Dhruvil
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > On Mon, Sep 7, 2020 at 6:54 PM Harsha Ch <
> > > > > > > harsha.ch@gmail.com>
> > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Hi All,
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > We are all working through the last meeting
> > > > feedback.
> > > > > > > I'll
> > > > > > > > > cancel
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > > tomorrow 's meeting and we can meanwhile
> > continue
> > > > our
> > > > > > > > > discussion in
> > > > > > > > > > > > > mailing
> > > > > > > > > > > > > > > > list. We can start the regular meeting from
> > next
> > > > week
> > > > > > > > > onwards.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Harsha
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > On Fri, Sep 04, 2020 at 8:41 AM, Satish
> > Duggana <
> > > > > > > > > > > > > satish.duggana@gmail.com
> > > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Hi Jun,
> > > > > > > > > > > > > > > > > Thanks for your thorough review and
> comments.
> > > > > Please
> > > > > > > find
> > > > > > > > > the
> > > > > > > > > > > > > inline
> > > > > > > > > > > > > > > > > replies below.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 600. The topic deletion logic needs more
> > details.
> > > > > > > > > > > > > > > > > 600.1 The KIP mentions "The controller
> > considers
> > > > > the
> > > > > > > topic
> > > > > > > > > > > > > partition is
> > > > > > > > > > > > > > > > > deleted only when it determines that there
> > are no
> > > > > log
> > > > > > > > > segments
> > > > > > > > > > > > for
> > > > > > > > > > > > > that
> > > > > > > > > > > > > > > > > topic partition by using RLMM". How is this
> > done?
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > It uses RLMM#listSegments() returns all the
> > > > > segments
> > > > > > > for
> > > > > > > > > the
> > > > > > > > > > > > given
> > > > > > > > > > > > > topic
> > > > > > > > > > > > > > > > > partition.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 600.2 "If the delete option is enabled then
> > the
> > > > > leader
> > > > > > > > > will stop
> > > > > > > > > > > > > RLM task
> > > > > > > > > > > > > > > > > and stop processing and it sets all the
> > remote
> > > > log
> > > > > > > segment
> > > > > > > > > > > > > metadata of
> > > > > > > > > > > > > > > > > that partition with a delete marker and
> > publishes
> > > > > them
> > > > > > > to
> > > > > > > > > RLMM."
> > > > > > > > > > > > We
> > > > > > > > > > > > > > > > > discussed this earlier. When a topic is
> being
> > > > > deleted,
> > > > > > > > > there may
> > > > > > > > > > > > > not be a
> > > > > > > > > > > > > > > > > leader for the deleted partition.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > This is a good point. As suggested in the
> > > > meeting,
> > > > > we
> > > > > > > will
> > > > > > > > > add a
> > > > > > > > > > > > > separate
> > > > > > > > > > > > > > > > > section for topic/partition deletion
> > lifecycle
> > > > and
> > > > > this
> > > > > > > > > scenario
> > > > > > > > > > > > > will be
> > > > > > > > > > > > > > > > > addressed.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 601. Unclean leader election
> > > > > > > > > > > > > > > > > 601.1 Scenario 1: new empty follower
> > > > > > > > > > > > > > > > > After step 1, the follower restores up to
> > offset
> > > > > 3. So
> > > > > > > why
> > > > > > > > > does
> > > > > > > > > > > > it
> > > > > > > > > > > > > have
> > > > > > > > > > > > > > > > > LE-2 <
> > https://issues.apache.org/jira/browse/LE-2
> > > > >
> > > > > at
> > > > > > > > > offset 5?
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Nice catch. It was showing the leader epoch
> > > > fetched
> > > > > > > from
> > > > > > > > > the
> > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > storage. It should be shown with the
> > truncated
> > > > till
> > > > > > > offset
> > > > > > > > > 3.
> > > > > > > > > > > > > Updated the
> > > > > > > > > > > > > > > > > KIP.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 601.2 senario 5: After Step 3, leader A has
> > > > > > > inconsistent
> > > > > > > > > data
> > > > > > > > > > > > > between its
> > > > > > > > > > > > > > > > > local and the tiered data. For example.
> > offset 3
> > > > > has
> > > > > > > msg 3
> > > > > > > > > LE-0
> > > > > > > > > > > > > <https://issues.apache.org/jira/browse/LE-0>
> > locally,
> > > > > > > > > > > > > > > > > but msg 5 LE-1 <
> > > > > > > https://issues.apache.org/jira/browse/LE-1>
> > > > > > > > > in
> > > > > > > > > > > > > the remote store. While it's ok for the unclean
> > leader
> > > > > > > > > > > > > > > > > to lose data, it should still return
> > consistent
> > > > > data,
> > > > > > > > > whether
> > > > > > > > > > > > it's
> > > > > > > > > > > > > from
> > > > > > > > > > > > > > > > > the local or the remote store.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > There is no inconsistency here as LE-0
> > > > > > > > > > > > > <https://issues.apache.org/jira/browse/LE-0>
> > offsets are
> > > > > [0,
> > > > > > > 4]
> > > > > > > > > and LE-2
> > > > > > > > > > > > > <https://issues.apache.org/jira/browse/LE-2>:
> > > > > > > > > > > > > > > > > [5, ]. It will always get the right records
> > for
> > > > the
> > > > > > > given
> > > > > > > > > offset
> > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > leader epoch. In case of remote, RSM is
> > invoked
> > > > to
> > > > > get
> > > > > > > the
> > > > > > > > > remote
> > > > > > > > > > > > > log
> > > > > > > > > > > > > > > > > segment that contains the given offset with
> > the
> > > > > leader
> > > > > > > > > epoch.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 601.4 It seems that retention is based on
> > > > > > > > > > > > > > > > > listRemoteLogSegments(TopicPartition
> > > > > topicPartition,
> > > > > > > long
> > > > > > > > > > > > > leaderEpoch).
> > > > > > > > > > > > > > > > > When there is an unclean leader election,
> > it's
> > > > > possible
> > > > > > > > > for the
> > > > > > > > > > > > new
> > > > > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > > to not to include certain epochs in its
> epoch
> > > > > cache.
> > > > > > > How
> > > > > > > > > are
> > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > segments associated with those epochs being
> > > > > cleaned?
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > That is a good point. This leader will also
> > > > > cleanup the
> > > > > > > > > epochs
> > > > > > > > > > > > > earlier to
> > > > > > > > > > > > > > > > > its start leader epoch and delete those
> > segments.
> > > > > It
> > > > > > > gets
> > > > > > > > > the
> > > > > > > > > > > > > earliest
> > > > > > > > > > > > > > > > > epoch for a partition and starts deleting
> > > > segments
> > > > > from
> > > > > > > > > that
> > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > epoch.
> > > > > > > > > > > > > > > > > We need one more API in RLMM to get the
> > earliest
> > > > > leader
> > > > > > > > > epoch.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 601.5 The KIP discusses the handling of
> > unclean
> > > > > leader
> > > > > > > > > elections
> > > > > > > > > > > > > for user
> > > > > > > > > > > > > > > > > topics. What about unclean leader elections
> > on
> > > > > > > > > > > > > > > > > __remote_log_segment_metadata?
> > > > > > > > > > > > > > > > > This is the same as other system topics
> like
> > > > > > > > > consumer_offsets,
> > > > > > > > > > > > > > > > > __transaction_state topics. As discussed in
> > the
> > > > > > > meeting,
> > > > > > > > > we will
> > > > > > > > > > > > > add the
> > > > > > > > > > > > > > > > > behavior of __remote_log_segment_metadata
> > topic’s
> > > > > > > unclean
> > > > > > > > > leader
> > > > > > > > > > > > > > > > > truncation.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 602. It would be useful to clarify the
> > > > limitations
> > > > > in
> > > > > > > the
> > > > > > > > > initial
> > > > > > > > > > > > > > > > release.
> > > > > > > > > > > > > > > > > The KIP mentions not supporting compacted
> > topics.
> > > > > What
> > > > > > > > > about JBOD
> > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > changing the configuration of a topic from
> > delete
> > > > > to
> > > > > > > > > compact
> > > > > > > > > > > > after
> > > > > > > > > > > > > > > > remote.
> > > > > > > > > > > > > > > > > log. storage. enable (
> > > > > > > http://remote.log.storage.enable/
> > > > > > > > > ) is
> > > > > > > > > > > > > enabled?
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > This was updated in the KIP earlier.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 603. RLM leader tasks:
> > > > > > > > > > > > > > > > > 603.1"It checks for rolled over LogSegments
> > > > (which
> > > > > have
> > > > > > > > > the last
> > > > > > > > > > > > > message
> > > > > > > > > > > > > > > > > offset less than last stable offset of that
> > topic
> > > > > > > > > partition) and
> > > > > > > > > > > > > copies
> > > > > > > > > > > > > > > > > them along with their
> offset/time/transaction
> > > > > indexes
> > > > > > > and
> > > > > > > > > leader
> > > > > > > > > > > > > epoch
> > > > > > > > > > > > > > > > > cache to the remote tier." It needs to copy
> > the
> > > > > > > producer
> > > > > > > > > snapshot
> > > > > > > > > > > > > too.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Right. It copies producer snapshots too as
> > > > > mentioned in
> > > > > > > > > > > > > LogSegmentData.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 603.2 "Local logs are not cleaned up till
> > those
> > > > > > > segments
> > > > > > > > > are
> > > > > > > > > > > > copied
> > > > > > > > > > > > > > > > > successfully to remote even though their
> > > > retention
> > > > > > > > > time/size is
> > > > > > > > > > > > > reached"
> > > > > > > > > > > > > > > > > This seems weird. If the tiering stops
> > because
> > > > the
> > > > > > > remote
> > > > > > > > > store
> > > > > > > > > > > > is
> > > > > > > > > > > > > not
> > > > > > > > > > > > > > > > > available, we don't want the local data to
> > grow
> > > > > > > forever.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > It was clarified in the discussion that the
> > > > > comment was
> > > > > > > > > more
> > > > > > > > > > > > about
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > local storage goes beyond the
> log.retention.
> > The
> > > > > above
> > > > > > > > > statement
> > > > > > > > > > > > > is about
> > > > > > > > > > > > > > > > > local.log.retention but not for the
> complete
> > > > > > > > > log.retention. When
> > > > > > > > > > > > it
> > > > > > > > > > > > > > > > > reaches the log.retention then it will
> > delete the
> > > > > local
> > > > > > > > > logs even
> > > > > > > > > > > > > though
> > > > > > > > > > > > > > > > > those are not copied to remote storage.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 604. "RLM maintains a bounded
> cache(possibly
> > LRU)
> > > > > of
> > > > > > > the
> > > > > > > > > index
> > > > > > > > > > > > > files of
> > > > > > > > > > > > > > > > > remote log segments to avoid multiple index
> > > > fetches
> > > > > > > from
> > > > > > > > > the
> > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > storage. These indexes can be used in the
> > same
> > > > way
> > > > > as
> > > > > > > local
> > > > > > > > > > > > segment
> > > > > > > > > > > > > > > > > indexes are used." Could you provide more
> > details
> > > > > on
> > > > > > > this?
> > > > > > > > > Are
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > > indexes
> > > > > > > > > > > > > > > > > cached in memory or on disk? If on disk,
> > where
> > > > are
> > > > > they
> > > > > > > > > stored?
> > > > > > > > > > > > > Are the
> > > > > > > > > > > > > > > > > cached indexes bound by a certain size?
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > These are cached on disk and stored in
> > log.dir
> > > > > with a
> > > > > > > name
> > > > > > > > > > > > > > > > > “__remote_log_index_cache”. They are bound
> > by the
> > > > > total
> > > > > > > > > size.
> > > > > > > > > > > > This
> > > > > > > > > > > > > will
> > > > > > > > > > > > > > > > be
> > > > > > > > > > > > > > > > > exposed as a user configuration,
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 605. BuildingRemoteLogAux
> > > > > > > > > > > > > > > > > 605.1 In this section, two options are
> > listed.
> > > > > Which
> > > > > > > one is
> > > > > > > > > > > > chosen?
> > > > > > > > > > > > > > > > > Option-2, updated the KIP.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 605.2 In option 2, it says "Build the local
> > > > leader
> > > > > > > epoch
> > > > > > > > > cache by
> > > > > > > > > > > > > cutting
> > > > > > > > > > > > > > > > > the leader epoch sequence received from
> > remote
> > > > > storage
> > > > > > > to
> > > > > > > > > [LSO,
> > > > > > > > > > > > > ELO].
> > > > > > > > > > > > > > > > (LSO
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > = log start offset)." We need to do the
> same
> > > > thing
> > > > > for
> > > > > > > the
> > > > > > > > > > > > producer
> > > > > > > > > > > > > > > > > snapshot. However, it's hard to cut the
> > producer
> > > > > > > snapshot
> > > > > > > > > to an
> > > > > > > > > > > > > earlier
> > > > > > > > > > > > > > > > > offset. Another option is to simply take
> the
> > > > > lastOffset
> > > > > > > > > from the
> > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > segment and use that as the starting fetch
> > offset
> > > > > in
> > > > > > > the
> > > > > > > > > > > > follower.
> > > > > > > > > > > > > This
> > > > > > > > > > > > > > > > > avoids the need for cutting.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Right, this was mentioned in the
> > “transactional
> > > > > > > support”
> > > > > > > > > section
> > > > > > > > > > > > > about
> > > > > > > > > > > > > > > > > adding these details.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 606. ListOffsets: Since we need a version
> > bump,
> > > > > could
> > > > > > > you
> > > > > > > > > > > > document
> > > > > > > > > > > > > it
> > > > > > > > > > > > > > > > > under a protocol change section?
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Sure, we will update the KIP.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 607. "LogStartOffset of a topic can point
> to
> > > > > either of
> > > > > > > > > local
> > > > > > > > > > > > > segment or
> > > > > > > > > > > > > > > > > remote segment but it is initialised and
> > > > > maintained in
> > > > > > > the
> > > > > > > > > Log
> > > > > > > > > > > > > class like
> > > > > > > > > > > > > > > > > now. This is already maintained in `Log`
> > class
> > > > > while
> > > > > > > > > loading the
> > > > > > > > > > > > > logs and
> > > > > > > > > > > > > > > > > it can also be fetched from
> > > > > RemoteLogMetadataManager."
> > > > > > > > > What will
> > > > > > > > > > > > > happen
> > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > the existing logic (e.g. log recovery) that
> > > > > currently
> > > > > > > > > depends on
> > > > > > > > > > > > > > > > > logStartOffset but assumes it's local?
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > They use a field called localLogStartOffset
> > which
> > > > > is
> > > > > > > the
> > > > > > > > > local
> > > > > > > > > > > > log
> > > > > > > > > > > > > start
> > > > > > > > > > > > > > > > > offset..
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 608. Handle expired remote segment: How
> does
> > it
> > > > > pick
> > > > > > > up new
> > > > > > > > > > > > > > > > logStartOffset
> > > > > > > > > > > > > > > > > from deleteRecords?
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Good point. This was not addressed in the
> > KIP.
> > > > Will
> > > > > > > update
> > > > > > > > > the
> > > > > > > > > > > > KIP
> > > > > > > > > > > > > on how
> > > > > > > > > > > > > > > > > the RLM task handles this scenario.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 609. RLMM message format:
> > > > > > > > > > > > > > > > > 609.1 It includes both MaxTimestamp and
> > > > > EventTimestamp.
> > > > > > > > > Where
> > > > > > > > > > > > does
> > > > > > > > > > > > > it get
> > > > > > > > > > > > > > > > > both since the message in the log only
> > contains
> > > > one
> > > > > > > > > timestamp?
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > `EventTimeStamp` is the timestamp at which
> > that
> > > > > segment
> > > > > > > > > metadata
> > > > > > > > > > > > > event is
> > > > > > > > > > > > > > > > > generated. This is more for audits.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 609.2 If we change just the state (e.g. to
> > > > > > > > > DELETE_STARTED), it
> > > > > > > > > > > > > seems it's
> > > > > > > > > > > > > > > > > wasteful to have to include all other
> fields
> > not
> > > > > > > changed.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > This is a good point. We thought about
> > > > incremental
> > > > > > > > > updates. But
> > > > > > > > > > > > we
> > > > > > > > > > > > > want
> > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > make sure all the events are in the
> expected
> > > > order
> > > > > and
> > > > > > > take
> > > > > > > > > > > > action
> > > > > > > > > > > > > based
> > > > > > > > > > > > > > > > > on the latest event. Will think through the
> > > > > approaches
> > > > > > > in
> > > > > > > > > detail
> > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > update here.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 609.3 Could you document which process
> makes
> > the
> > > > > > > following
> > > > > > > > > > > > > transitions
> > > > > > > > > > > > > > > > > DELETE_MARKED, DELETE_STARTED,
> > DELETE_FINISHED?
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Okay, will document more details.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 610. remote.log.reader.max.pending.tasks:
> > > > "Maximum
> > > > > > > remote
> > > > > > > > > log
> > > > > > > > > > > > > reader
> > > > > > > > > > > > > > > > > thread pool task queue size. If the task
> > queue is
> > > > > full,
> > > > > > > > > broker
> > > > > > > > > > > > > will stop
> > > > > > > > > > > > > > > > > reading remote log segments." What does the
> > > > broker
> > > > > do
> > > > > > > if
> > > > > > > > > the
> > > > > > > > > > > > queue
> > > > > > > > > > > > > is
> > > > > > > > > > > > > > > > > full?
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > It returns an error for this topic
> partition.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 611. What do we return if the request
> > > > offset/epoch
> > > > > > > doesn't
> > > > > > > > > exist
> > > > > > > > > > > > > in the
> > > > > > > > > > > > > > > > > following API?
> > > > > > > > > > > > > > > > > RemoteLogSegmentMetadata
> > > > > > > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > > > > > > > > > topicPartition, long offset, int
> > epochForOffset)
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > This returns null. But we prefer to update
> > the
> > > > > return
> > > > > > > type
> > > > > > > > > as
> > > > > > > > > > > > > Optional
> > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > return Empty if that does not exist.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > > Satish.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > On Tue, Sep 1, 2020 at 9:45 AM Jun Rao <
> jun@
> > > > > > > confluent.
> > > > > > > > > io (
> > > > > > > > > > > > > > > > > jun@confluent.io ) > wrote:
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >> Hi, Satish,
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >> Thanks for the updated KIP. Made another
> > pass. A
> > > > > few
> > > > > > > more
> > > > > > > > > > > > comments
> > > > > > > > > > > > > > > > below.
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >> 600. The topic deletion logic needs more
> > > > details.
> > > > > > > > > > > > > > > > >> 600.1 The KIP mentions "The controller
> > considers
> > > > > the
> > > > > > > topic
> > > > > > > > > > > > > partition is
> > > > > > > > > > > > > > > > >> deleted only when it determines that there
> > are
> > > > no
> > > > > log
> > > > > > > > > segments
> > > > > > > > > > > > > for that
> > > > > > > > > > > > > > > > >> topic partition by using RLMM". How is
> this
> > > > done?
> > > > > > > 600.2
> > > > > > > > > "If the
> > > > > > > > > > > > > delete
> > > > > > > > > > > > > > > > >> option is enabled then the leader will
> stop
> > RLM
> > > > > task
> > > > > > > and
> > > > > > > > > stop
> > > > > > > > > > > > > processing
> > > > > > > > > > > > > > > > >> and it sets all the remote log segment
> > metadata
> > > > of
> > > > > > > that
> > > > > > > > > > > > partition
> > > > > > > > > > > > > with a
> > > > > > > > > > > > > > > > >> delete marker and publishes them to RLMM."
> > We
> > > > > > > discussed
> > > > > > > > > this
> > > > > > > > > > > > > earlier.
> > > > > > > > > > > > > > > > When
> > > > > > > > > > > > > > > > >> a topic is being deleted, there may not
> be a
> > > > > leader
> > > > > > > for
> > > > > > > > > the
> > > > > > > > > > > > > deleted
> > > > > > > > > > > > > > > > >> partition.
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >> 601. Unclean leader election
> > > > > > > > > > > > > > > > >> 601.1 Scenario 1: new empty follower
> > > > > > > > > > > > > > > > >> After step 1, the follower restores up to
> > offset
> > > > > 3. So
> > > > > > > > > why does
> > > > > > > > > > > > > it have
> > > > > > > > > > > > > > > > >> LE-2 <
> > > > https://issues.apache.org/jira/browse/LE-2>
> > > > > at
> > > > > > > > > offset 5?
> > > > > > > > > > > > > > > > >> 601.2 senario 5: After Step 3, leader A
> has
> > > > > > > inconsistent
> > > > > > > > > data
> > > > > > > > > > > > > between
> > > > > > > > > > > > > > > > its
> > > > > > > > > > > > > > > > >> local and the tiered data. For example.
> > offset 3
> > > > > has
> > > > > > > msg
> > > > > > > > > 3 LE-0
> > > > > > > > > > > > > <https://issues.apache.org/jira/browse/LE-0>
> > locally,
> > > > > > > > > > > > > > > > >> but msg 5 LE-1 <
> > > > > > > > > https://issues.apache.org/jira/browse/LE-1> in
> > > > > > > > > > > > > the remote store. While it's ok for the unclean
> > leader
> > > > > > > > > > > > > > > > >> to lose data, it should still return
> > consistent
> > > > > data,
> > > > > > > > > whether
> > > > > > > > > > > > > it's from
> > > > > > > > > > > > > > > > >> the local or the remote store.
> > > > > > > > > > > > > > > > >> 601.3 The follower picks up log start
> offset
> > > > > using the
> > > > > > > > > following
> > > > > > > > > > > > > api.
> > > > > > > > > > > > > > > > >> Suppose that we have 3 remote segments
> (LE,
> > > > > > > > > SegmentStartOffset)
> > > > > > > > > > > > > as (2,
> > > > > > > > > > > > > > > > >> 10),
> > > > > > > > > > > > > > > > >> (3, 20) and (7, 15) due to an unclean
> leader
> > > > > election.
> > > > > > > > > Using the
> > > > > > > > > > > > > > > > following
> > > > > > > > > > > > > > > > >> api will cause logStartOffset to go
> backward
> > > > from
> > > > > 20
> > > > > > > to
> > > > > > > > > 15. How
> > > > > > > > > > > > > do we
> > > > > > > > > > > > > > > > >> prevent that?
> > > > > > > > > > > > > > > > >> earliestLogOffset(TopicPartition
> > topicPartition,
> > > > > int
> > > > > > > > > > > > leaderEpoch)
> > > > > > > > > > > > > 601.4
> > > > > > > > > > > > > > > > It
> > > > > > > > > > > > > > > > >> seems that retention is based on
> > > > > > > > > > > > > > > > >> listRemoteLogSegments(TopicPartition
> > > > > topicPartition,
> > > > > > > long
> > > > > > > > > > > > > leaderEpoch).
> > > > > > > > > > > > > > > > >> When there is an unclean leader election,
> > it's
> > > > > > > possible
> > > > > > > > > for the
> > > > > > > > > > > > > new
> > > > > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > >> to not to include certain epochs in its
> > epoch
> > > > > cache.
> > > > > > > How
> > > > > > > > > are
> > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > >> segments associated with those epochs
> being
> > > > > cleaned?
> > > > > > > > > 601.5 The
> > > > > > > > > > > > KIP
> > > > > > > > > > > > > > > > >> discusses the handling of unclean leader
> > > > > elections for
> > > > > > > > > user
> > > > > > > > > > > > > topics. What
> > > > > > > > > > > > > > > > >> about unclean leader elections on
> > > > > > > > > > > > > > > > >> __remote_log_segment_metadata?
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >> 602. It would be useful to clarify the
> > > > > limitations in
> > > > > > > the
> > > > > > > > > > > > initial
> > > > > > > > > > > > > > > > release.
> > > > > > > > > > > > > > > > >> The KIP mentions not supporting compacted
> > > > topics.
> > > > > What
> > > > > > > > > about
> > > > > > > > > > > > JBOD
> > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > >> changing the configuration of a topic from
> > > > delete
> > > > > to
> > > > > > > > > compact
> > > > > > > > > > > > after
> > > > > > > > > > > > > > > > remote.
> > > > > > > > > > > > > > > > >> log. storage. enable (
> > > > > > > http://remote.log.storage.enable/
> > > > > > > > > ) is
> > > > > > > > > > > > > enabled?
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >> 603. RLM leader tasks:
> > > > > > > > > > > > > > > > >> 603.1"It checks for rolled over
> LogSegments
> > > > (which
> > > > > > > have
> > > > > > > > > the last
> > > > > > > > > > > > > message
> > > > > > > > > > > > > > > > >> offset less than last stable offset of
> that
> > > > topic
> > > > > > > > > partition) and
> > > > > > > > > > > > > copies
> > > > > > > > > > > > > > > > >> them along with their
> > offset/time/transaction
> > > > > indexes
> > > > > > > and
> > > > > > > > > leader
> > > > > > > > > > > > > epoch
> > > > > > > > > > > > > > > > >> cache to the remote tier." It needs to
> copy
> > the
> > > > > > > producer
> > > > > > > > > > > > snapshot
> > > > > > > > > > > > > too.
> > > > > > > > > > > > > > > > >> 603.2 "Local logs are not cleaned up till
> > those
> > > > > > > segments
> > > > > > > > > are
> > > > > > > > > > > > > copied
> > > > > > > > > > > > > > > > >> successfully to remote even though their
> > > > retention
> > > > > > > > > time/size is
> > > > > > > > > > > > > reached"
> > > > > > > > > > > > > > > > >> This seems weird. If the tiering stops
> > because
> > > > the
> > > > > > > remote
> > > > > > > > > store
> > > > > > > > > > > > > is not
> > > > > > > > > > > > > > > > >> available, we don't want the local data to
> > grow
> > > > > > > forever.
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >> 604. "RLM maintains a bounded
> cache(possibly
> > > > LRU)
> > > > > of
> > > > > > > the
> > > > > > > > > index
> > > > > > > > > > > > > files of
> > > > > > > > > > > > > > > > >> remote log segments to avoid multiple
> index
> > > > > fetches
> > > > > > > from
> > > > > > > > > the
> > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > >> storage. These indexes can be used in the
> > same
> > > > > way as
> > > > > > > > > local
> > > > > > > > > > > > > segment
> > > > > > > > > > > > > > > > >> indexes are used." Could you provide more
> > > > details
> > > > > on
> > > > > > > > > this? Are
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > > indexes
> > > > > > > > > > > > > > > > >> cached in memory or on disk? If on disk,
> > where
> > > > are
> > > > > > > they
> > > > > > > > > stored?
> > > > > > > > > > > > > Are the
> > > > > > > > > > > > > > > > >> cached indexes bound by a certain size?
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >> 605. BuildingRemoteLogAux
> > > > > > > > > > > > > > > > >> 605.1 In this section, two options are
> > listed.
> > > > > Which
> > > > > > > one
> > > > > > > > > is
> > > > > > > > > > > > > chosen?
> > > > > > > > > > > > > > > > 605.2
> > > > > > > > > > > > > > > > >> In option 2, it says "Build the local
> leader
> > > > epoch
> > > > > > > cache
> > > > > > > > > by
> > > > > > > > > > > > > cutting the
> > > > > > > > > > > > > > > > >> leader epoch sequence received from remote
> > > > > storage to
> > > > > > > > > [LSO,
> > > > > > > > > > > > ELO].
> > > > > > > > > > > > > (LSO
> > > > > > > > > > > > > > > > >> = log start offset)." We need to do the
> same
> > > > thing
> > > > > > > for the
> > > > > > > > > > > > > producer
> > > > > > > > > > > > > > > > >> snapshot. However, it's hard to cut the
> > producer
> > > > > > > snapshot
> > > > > > > > > to an
> > > > > > > > > > > > > earlier
> > > > > > > > > > > > > > > > >> offset. Another option is to simply take
> the
> > > > > > > lastOffset
> > > > > > > > > from the
> > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > >> segment and use that as the starting fetch
> > > > offset
> > > > > in
> > > > > > > the
> > > > > > > > > > > > > follower. This
> > > > > > > > > > > > > > > > >> avoids the need for cutting.
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >> 606. ListOffsets: Since we need a version
> > bump,
> > > > > could
> > > > > > > you
> > > > > > > > > > > > > document it
> > > > > > > > > > > > > > > > >> under a protocol change section?
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >> 607. "LogStartOffset of a topic can point
> to
> > > > > either of
> > > > > > > > > local
> > > > > > > > > > > > > segment or
> > > > > > > > > > > > > > > > >> remote segment but it is initialised and
> > > > > maintained in
> > > > > > > > > the Log
> > > > > > > > > > > > > class
> > > > > > > > > > > > > > > > like
> > > > > > > > > > > > > > > > >> now. This is already maintained in `Log`
> > class
> > > > > while
> > > > > > > > > loading the
> > > > > > > > > > > > > logs
> > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > >> it can also be fetched from
> > > > > RemoteLogMetadataManager."
> > > > > > > > > What will
> > > > > > > > > > > > > happen
> > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > >> the existing logic (e.g. log recovery)
> that
> > > > > currently
> > > > > > > > > depends on
> > > > > > > > > > > > > > > > >> logStartOffset but assumes it's local?
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >> 608. Handle expired remote segment: How
> > does it
> > > > > pick
> > > > > > > up
> > > > > > > > > new
> > > > > > > > > > > > > > > > logStartOffset
> > > > > > > > > > > > > > > > >> from deleteRecords?
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >> 609. RLMM message format:
> > > > > > > > > > > > > > > > >> 609.1 It includes both MaxTimestamp and
> > > > > > > EventTimestamp.
> > > > > > > > > Where
> > > > > > > > > > > > > does it
> > > > > > > > > > > > > > > > get
> > > > > > > > > > > > > > > > >> both since the message in the log only
> > contains
> > > > > one
> > > > > > > > > timestamp?
> > > > > > > > > > > > > 609.2 If
> > > > > > > > > > > > > > > > we
> > > > > > > > > > > > > > > > >> change just the state (e.g. to
> > DELETE_STARTED),
> > > > it
> > > > > > > seems
> > > > > > > > > it's
> > > > > > > > > > > > > wasteful
> > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > >> have to include all other fields not
> > changed.
> > > > > 609.3
> > > > > > > Could
> > > > > > > > > you
> > > > > > > > > > > > > document
> > > > > > > > > > > > > > > > >> which process makes the following
> > transitions
> > > > > > > > > DELETE_MARKED,
> > > > > > > > > > > > > > > > >> DELETE_STARTED, DELETE_FINISHED?
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >> 610. remote.log.reader.max.pending.tasks:
> > > > "Maximum
> > > > > > > remote
> > > > > > > > > log
> > > > > > > > > > > > > reader
> > > > > > > > > > > > > > > > >> thread pool task queue size. If the task
> > queue
> > > > is
> > > > > > > full,
> > > > > > > > > broker
> > > > > > > > > > > > > will stop
> > > > > > > > > > > > > > > > >> reading remote log segments." What does
> the
> > > > > broker do
> > > > > > > if
> > > > > > > > > the
> > > > > > > > > > > > > queue is
> > > > > > > > > > > > > > > > >> full?
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >> 611. What do we return if the request
> > > > offset/epoch
> > > > > > > > > doesn't exist
> > > > > > > > > > > > > in the
> > > > > > > > > > > > > > > > >> following API?
> > > > > > > > > > > > > > > > >> RemoteLogSegmentMetadata
> > > > > > > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > > > > > > > > >> topicPartition, long offset, int
> > epochForOffset)
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >> Jun
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >> On Mon, Aug 31, 2020 at 11:19 AM Satish
> > Duggana
> > > > <
> > > > > > > satish.
> > > > > > > > > > > > duggana@
> > > > > > > > > > > > > > > > gmail. com
> > > > > > > > > > > > > > > > >> ( satish.duggana@gmail.com ) > wrote:
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>> KIP is updated with
> > > > > > > > > > > > > > > > >>> - Remote log segment metadata topic
> message
> > > > > > > > > format/schema.
> > > > > > > > > > > > > > > > >>> - Added remote log segment metadata state
> > > > > > > transitions and
> > > > > > > > > > > > > explained how
> > > > > > > > > > > > > > > > >>> the deletion of segments is handled,
> > including
> > > > > the
> > > > > > > case
> > > > > > > > > of
> > > > > > > > > > > > > partition
> > > > > > > > > > > > > > > > >>> deletions.
> > > > > > > > > > > > > > > > >>> - Added a few more limitations in the
> "Non
> > > > goals"
> > > > > > > > > section.
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>> Thanks,
> > > > > > > > > > > > > > > > >>> Satish.
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>> On Thu, Aug 27, 2020 at 12:42 AM Harsha
> Ch
> > <
> > > > > harsha.
> > > > > > > ch@
> > > > > > > > > > > > gmail.
> > > > > > > > > > > > > com (
> > > > > > > > > > > > > > > > >>> harsha.ch@gmail.com ) > wrote:
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>> Updated the KIP with Meeting Notes
> section
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>> https:/ / cwiki. apache. org/ confluence/
> > > > > display/
> > > > > > > KAFKA/
> > > > > > > > > > > > > > > > KIP-405 <
> > > > > https://issues.apache.org/jira/browse/KIP-405>
> > > > > > > > > > > > >
> > > > > %3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> > > > > > > > > > > > > > > > >>> (
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > >
> > > > > > >
> > > > >
> > > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-405%3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> > > > > > > > > > > > > > > > >>> )
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>> On Tue, Aug 25, 2020 at 1:03 PM Jun Rao
> <
> > jun@
> > > > > > > > > confluent. io
> > > > > > > > > > > > (
> > > > > > > > > > > > > > > > >>>> jun@confluent.io ) > wrote:
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>> Hi, Harsha,
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>> Thanks for the summary. Could you add
> the
> > > > > summary
> > > > > > > and
> > > > > > > > > the
> > > > > > > > > > > > > recording
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>> link to
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>> the last section of
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>> https:/ / cwiki. apache. org/ confluence/
> > > > > display/
> > > > > > > KAFKA/
> > > > > > > > > > > > > > > > Kafka+Improvement+Proposals
> > > > > > > > > > > > > > > > >>> (
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > >
> > > > > > >
> > > > >
> > > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/Kafka+Improvement+Proposals
> > > > > > > > > > > > > > > > >>> )
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>> ?
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>> Jun
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>> On Tue, Aug 25, 2020 at 11:12 AM Harsha
> > > > > > > Chintalapani <
> > > > > > > > > kafka@
> > > > > > > > > > > > > > > > harsha. io (
> > > > > > > > > > > > > > > > >>>>> kafka@harsha.io ) > wrote:
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>> Thanks everyone for attending the
> > meeting
> > > > > today.
> > > > > > > > > > > > > > > > >>>>>> Here is the recording
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>> https:/ / drive. google. com/ file/ d/
> > > > > > > > > > > > > > > > 14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/
> > view?usp=sharing
> > > > > > > > > > > > > > > > >>> (
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > >
> > > > > > >
> > > > >
> > > >
> >
> https://drive.google.com/file/d/14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/view?usp=sharing
> > > > > > > > > > > > > > > > >>> )
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>> Notes:
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>> 1. KIP is updated with follower fetch
> > > > > protocol and
> > > > > > > > > ready to
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>> reviewed
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>> 2. Satish to capture schema of
> internal
> > > > > metadata
> > > > > > > > > topic in
> > > > > > > > > > > > the
> > > > > > > > > > > > > KIP
> > > > > > > > > > > > > > > > >>>>>> 3. We will update the KIP with details
> > of
> > > > > > > different
> > > > > > > > > cases
> > > > > > > > > > > > > > > > >>>>>> 4. Test plan will be captured in a doc
> > and
> > > > > will
> > > > > > > add
> > > > > > > > > to the
> > > > > > > > > > > > KIP
> > > > > > > > > > > > > > > > >>>>>> 5. Add a section "Limitations" to
> > capture
> > > > the
> > > > > > > > > capabilities
> > > > > > > > > > > > > that
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>> will
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>> be
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>> introduced with this KIP and what will
> > not
> > > > be
> > > > > > > covered
> > > > > > > > > in
> > > > > > > > > > > > this
> > > > > > > > > > > > > KIP.
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>> Please add to it I missed anything.
> Will
> > > > > produce a
> > > > > > > > > formal
> > > > > > > > > > > > > meeting
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>> notes
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>> from next meeting onwards.
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>> Thanks,
> > > > > > > > > > > > > > > > >>>>>> Harsha
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>> On Mon, Aug 24, 2020 at 9:42 PM, Ying
> > Zheng
> > > > <
> > > > > > > yingz@
> > > > > > > > > uber.
> > > > > > > > > > > > > com.
> > > > > > > > > > > > > > > > invalid (
> > > > > > > > > > > > > > > > >>>>>> yingz@uber.com.invalid ) > wrote:
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> We did some basic feature tests at
> > Uber.
> > > > The
> > > > > test
> > > > > > > > > cases and
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>> results are
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> shared in this google doc:
> > > > > > > > > > > > > > > > >>>>>>> https:/ / docs. google. com/
> > spreadsheets/
> > > > > d/ (
> > > > > > > > > > > > > > > > >>>>>>>
> > https://docs.google.com/spreadsheets/d/ )
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >
> > > > 1XhNJqjzwXvMCcAOhEH0sSXU6RTvyoSf93DHF-YMfGLk/edit?usp=sharing
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> The performance test results were
> > already
> > > > > shared
> > > > > > > in
> > > > > > > > > the KIP
> > > > > > > > > > > > > last
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>> month.
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> On Mon, Aug 24, 2020 at 11:10 AM
> > Harsha Ch
> > > > <
> > > > > > > harsha.
> > > > > > > > > ch@
> > > > > > > > > > > > > gmail.
> > > > > > > > > > > > > > > > com (
> > > > > > > > > > > > > > > > >>>>>>> harsha.ch@gmail.com ) >
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>> wrote:
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> "Understand commitments towards
> driving
> > > > > design &
> > > > > > > > > > > > > implementation of
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>> the
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>> KIP
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> further and how it aligns with
> > participant
> > > > > > > interests
> > > > > > > > > in
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>> contributing to
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>> the
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> efforts (ex: in the context of Uber’s
> > Q3/Q4
> > > > > > > > > roadmap)." What
> > > > > > > > > > > > > is that
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>> about?
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> On Mon, Aug 24, 2020 at 11:05 AM
> > Kowshik
> > > > > > > Prakasam <
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>> kprakasam@ confluent. io (
> > > > > kprakasam@confluent.io
> > > > > > > ) >
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> wrote:
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> Hi Harsha,
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> The following google doc contains a
> > > > proposal
> > > > > for
> > > > > > > > > temporary
> > > > > > > > > > > > > agenda
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>> for
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>> the
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> KIP-405 <
> > > > > > > > > https://issues.apache.org/jira/browse/KIP-405> <
> > > > > > > > > > > > > https:/ / issues. apache. org/ jira/ browse/
> KIP-405
> > > > > > > > > > > > > <https://issues.apache.org/jira/browse/KIP-405> (
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > https://issues.apache.org/jira/browse/KIP-405 )
> > > > > > > >
> > > > > > > > > sync
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>> meeting
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> tomorrow:
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> https:/ / docs. google. com/
> document/
> > d/ (
> > > > > > > > > > > > > > > > >>>>>>> https://docs.google.com/document/d/
> )
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > 1pqo8X5LU8TpwfC_iqSuVPezhfCfhGkbGN2TqiPA3LBU/edit
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> .
> > > > > > > > > > > > > > > > >>>>>>> Please could you add it to the Google
> > > > > calendar
> > > > > > > > > invite?
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> Thank you.
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> Cheers,
> > > > > > > > > > > > > > > > >>>>>>> Kowshik
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> On Thu, Aug 20, 2020 at 10:58 AM
> > Harsha Ch
> > > > <
> > > > > > > harsha.
> > > > > > > > > ch@
> > > > > > > > > > > > > gmail.
> > > > > > > > > > > > > > > > com (
> > > > > > > > > > > > > > > > >>>>>>> harsha.ch@gmail.com ) >
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>> wrote:
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> Hi All,
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> Scheduled a meeting for Tuesday 9am -
> > 10am.
> > > > > I can
> > > > > > > > > record
> > > > > > > > > > > > and
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>> upload for
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> community to be able to follow the
> > > > > discussion.
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> Jun, please add the required folks on
> > > > > confluent
> > > > > > > side.
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> Thanks,
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> Harsha
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> On Thu, Aug 20, 2020 at 12:33 AM,
> > Alexandre
> > > > > > > Dupriez <
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>> alexandre.dupriez@
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> gmail. com ( http://gmail.com/ ) >
> > wrote:
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> Hi Jun,
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> Many thanks for your initiative.
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> If you like, I am happy to attend at
> > the
> > > > > time you
> > > > > > > > > > > > suggested.
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> Many thanks,
> > > > > > > > > > > > > > > > >>>>>>> Alexandre
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> Le mer. 19 août 2020 à 22:00, Harsha
> > Ch <
> > > > > > > harsha. ch@
> > > > > > > > > > > > > gmail. com (
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>> harsha.
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> ch@ gmail. com ( ch@gmail.com ) ) >
> a
> > > > écrit
> > > > > :
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> Hi Jun,
> > > > > > > > > > > > > > > > >>>>>>> Thanks. This will help a lot. Tuesday
> > will
> > > > > work
> > > > > > > for
> > > > > > > > > us.
> > > > > > > > > > > > > > > > >>>>>>> -Harsha
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> On Wed, Aug 19, 2020 at 1:24 PM Jun
> > Rao <
> > > > > jun@
> > > > > > > > > confluent.
> > > > > > > > > > > > > io (
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>> jun@
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> confluent. io ( http://confluent.io/
> > ) ) >
> > > > > > > wrote:
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> Hi, Satish, Ying, Harsha,
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> Do you think it would be useful to
> > have a
> > > > > regular
> > > > > > > > > virtual
> > > > > > > > > > > > > meeting
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>> to
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> discuss this KIP? The goal of the
> > meeting
> > > > > will be
> > > > > > > > > sharing
> > > > > > > > > > > > > > > > >>>>>>> design/development progress and
> > discussing
> > > > > any
> > > > > > > open
> > > > > > > > > issues
> > > > > > > > > > > > to
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> accelerate
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> this KIP. If so, will every Tuesday
> > (from
> > > > > next
> > > > > > > week)
> > > > > > > > > > > > 9am-10am
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> PT
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> work for you? I can help set up a
> Zoom
> > > > > meeting,
> > > > > > > > > invite
> > > > > > > > > > > > > everyone who
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> might
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> be interested, have it recorded and
> > shared,
> > > > > etc.
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> Thanks,
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> Jun
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> On Tue, Aug 18, 2020 at 11:01 AM
> Satish
> > > > > Duggana <
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> satish. duggana@ gmail. com (
> satish.
> > > > > duggana@
> > > > > > > > > gmail. com
> > > > > > > > > > > > (
> > > > > > > > > > > > > > > > >>>>>>> satish.duggana@gmail.com ) ) >
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> wrote:
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> Hi Kowshik,
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> Thanks for looking into the KIP and
> > sending
> > > > > your
> > > > > > > > > comments.
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> 5001. Under the section "Follower
> fetch
> > > > > protocol
> > > > > > > in
> > > > > > > > > > > > detail",
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > >>>>>>> next-local-offset is the offset upto
> > which
> > > > > the
> > > > > > > > > segments are
> > > > > > > > > > > > > copied
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > >
> > > > >
> > > >
> >
>

Re: [DISCUSS] KIP-405: Kafka Tiered Storage

[Satish Duggana <sa...@gmail.com>]

Hi Jun,
Thanks for your comments. Please find the inline replies below.

9300. Could we add a section on downgrade?

Added Downgrade section with the details as discussed.

9301. "Feature test cases and test results are documented in this google
spreadsheet <https://docs.google.com/spreadsheets/d/1XhNJqjzwXvMCcAOhEH0sSXU6RTvyoSf93DHF-YMfGLk/edit?usp=sharing>
." The google spreadsheet doesn't have a link. Could we add the plan
for integration and system systems?

For integration tests, we use file based(LocalTieredStorage)
RemoteStorageManager(RSM) . For system tests, we plan to have a single
node HDFS cluster in one of the containers and use HDFS RSM
implementation. This is updated in the KIP.  Doc for integration and
system testing doc is in progress. We will share it once it is ready.

~Satish.

On Tue, 9 Feb 2021 at 01:34, Jun Rao <ju...@confluent.io> wrote:
>
> Hi, Satish,
>
> Thanks for the reply. Just a couple of more comments.
>
> 9300. Could we add a section on downgrade?
>
> 9301. "Feature test cases and test results are documented in this google
> spreadsheet
> <https://docs.google.com/spreadsheets/d/1XhNJqjzwXvMCcAOhEH0sSXU6RTvyoSf93DHF-YMfGLk/edit?usp=sharing>
> ." The google spreadsheet doesn't have a link. Could we add the plan for
> integration and system systems?
>
> Jun
>
> On Mon, Feb 8, 2021 at 8:21 AM Satish Duggana <sa...@gmail.com>
> wrote:
>
> > Hi Manikumar,
> > Thanks for your comment. Please find the inline replies below.
> >
> > 9201. Can we make it clear by mentioning RLM as an internal component and
> > RLMM and RSM are pluggable components.
> > It's also good to update/add the RLM, RLMM components  diagrams with
> > internal components/tasks.
> >
> > Updated the KIP.
> >
> > 9202. RLMM metadata topic is a non-compact topic. Can we make clear that
> > metadata topic retention time should be greater
> >  than user topics. or How about setting retention set to -1 (unlimited) and
> > let users to modify it.
> >
> > I am fine with -1 and updated the configuration doc and made it clear
> > in the KIP.
> >
> > 9203. RLMM has additional responsibility of handling topic delete requests.
> > With current design, RLMM implementations need
> > to implement deletion logic. How about making RemotePartitionRemover as a
> > separate task, which can be reused..
> >
> > Good point. We had plans to address that in a future KIP, added in
> > future work items.
> >
> > 9204. Can we list all the new error codes added by the KIP?
> >
> > Those are mentioned in the protocol changes section.
> >
> > 9205. Can we also support  `remote.log.metadata.producr.*`,
> > `remote.log.metadata.consumer.*` prefixed configs to
> > override any default configs ?. also include RLMM cache configs, if any.
> >
> > Good point. Updated the KIP.
> >
> > 9206. In the Upgrade section, we have below statement
> > "Before enabling tiered storage, you should make sure the producer
> > snapshots are built for all the segments for that topic
> > in all followers. You should wait till the log retention occurs for all the
> > segments so that all the segments have producer snapshots."
> > Can you add more details about this constraint?
> >
> > Sure, updated in the KIP.
> >
> >
> > ~Satish.
> >
> > On Tue, 2 Feb 2021 at 21:04, Manikumar <ma...@gmail.com> wrote:
> > >
> > > Hi Satish,
> > >
> > > Thanks for the KIP.  some of my comments below.
> > >
> > > 9201. Can we make it clear by mentioning RLM as an internal component and
> > > RLMM and RSM are pluggable components.
> > > It's also good to update/add the RLM, RLMM components  diagrams with
> > > internal components/tasks.
> > >
> > > 9202. RLMM metadata topic is a non-compact topic. Can we make clear that
> > > metadata topic retention time should be greater
> > >  than user topics. or How about setting retention set to -1 (unlimited)
> > and
> > > let users to modify it.
> > >
> > > 9203. RLMM has additional responsibility of handling topic delete
> > requests.
> > > With current design, RLMM implementations need
> > > to implement deletion logic. How about making RemotePartitionRemover as a
> > > separate task, which can be reused..
> > >
> > > 9204. Can we list all the new error codes added by the KIP?
> > >
> > > 9205. Can we also support  `remote.log.metadata.producr.*`,
> > > `remote.log.metadata.consumer.*` prefixed configs to
> > > override any default configs ?. also include RLMM cache configs, if any.
> > >
> > > 9206. In the Upgrade section, we have below statement
> > > "Before enabling tiered storage, you should make sure the producer
> > > snapshots are built for all the segments for that topic
> > > in all followers. You should wait till the log retention occurs for all
> > the
> > > segments so that all the segments have producer snapshots."
> > >
> > >  Can you add more details about this constraint?
> > >
> > >
> > > Thanks,
> > > Manikumar
> > >
> > > On Tue, Jan 26, 2021 at 1:12 AM Jun Rao <ju...@confluent.io> wrote:
> > >
> > > > Hi, Satish,
> > > >
> > > > Thanks for the reply. A few more comments below.
> > > >
> > > > 6000. When RSM/RLMM is not available, it seems that we need to return a
> > > > retriable error to the affected client requests. So, should we add a
> > new
> > > > error code for requests like fetch and listOffset?
> > > >
> > > > 9111. RemotePartitionRemover:
> > > > 91111.1 Could we make it clear that it's part of the default RLMM
> > > > implementation and a separate implementation is needed if one has a
> > > > customized RLMM?
> > > > 91111.2 "RPRM gets all the remote log segments for the partition using
> > RLMM
> > > > and each of these remote log segments is deleted with the next
> > steps.RLMM
> > > > subscribes to the local remote log metadata partitions and it will
> > have the
> > > > segment metadata of all the user topic partitions associated with that
> > > > remote log metadata partition." It seems that RLMM needs to subscribe
> > to
> > > > the remote log metadata partitions first before those segments can be
> > > > deleted?
> > > > 9111.3 There are still references to "remote log cleaners". They need
> > to be
> > > > replaced with RemotePartitionRemover.
> > > >
> > > > 9114.1 Could we add the requirement on log.message.format before
> > enabling
> > > > tiered storage?
> > > >
> > > > 9116. RemoteLogMetadataFormatter: This is used with the ConsoleConsumer
> > > > tool, right? Then, are those new options for ConsoleConsumer and how
> > are
> > > > they passed in?
> > > >
> > > > Thanks,
> > > >
> > > > Jun
> > > >
> > > >
> > > > On Mon, Jan 25, 2021 at 8:02 AM Satish Duggana <
> > satish.duggana@gmail.com>
> > > > wrote:
> > > >
> > > > > Hi Jun,
> > > > >
> > > > > Thanks for your comments. Please find the inline replies below.
> > > > > Several of these were discussed/clarified in our last discussion.
> > > > >
> > > > > 6000. Since we are returning new error codes, we need to bump up the
> > > > > protocol version for Fetch request. Also, it will be useful to
> > document
> > > > all
> > > > > new error codes and whether they are retriable or not.
> > > > > This previous comment doesn't seem to be addressed.
> > > > >
> > > > > Updated KIP on fetch protocol and error code.
> > > > >
> > > > > 9110. flat_file_format: Could you define the serialized
> > representation
> > > > for
> > > > > each field in the header?
> > > > >
> > > > > Added the serialized representation types in the KIP.
> > > > >
> > > > > 9111. RPM has the following 2 steps.
> > > > > "1. The controller publishes delete_partition_marked event to say
> > that
> > > > the
> > > > > partition is marked for deletion. There can be multiple events
> > published
> > > > > when the controller restarts or failover and this event will be
> > > > > deduplicated by RPM.
> > > > > 2. RPM receives the delete_partition_marked and processes it if it
> > is not
> > > > > yet processed earlier."
> > > > > What triggers RPM to read __remote_log_metadata? Is RPM part of the
> > > > default
> > > > > RLMM implementation or is it meant for any RLMM implementation?
> > > > >
> > > > > RPM(or RPRM) is only for the default RLMM implementation. RPM
> > receives
> > > > > the delete_partition_marked events from RLMM and acts on them.
> > Updated
> > > > > KIP with more details.
> > > > >
> > > > > 9112. remote.log.manager.task.retry.backoff.ms: It would be useful
> > to
> > > > make
> > > > > it clear in the comment that this is for the initial retry backoff.
> > > > >
> > > > > Updated the KIP.
> > > > >
> > > > > 9113. RLMM:
> > > > > 9113.1 updateRemoteLogSegmentMetadata(): This comment needs to be
> > > > updated.
> > > > >
> > > > > Updated javadoc of this method.
> > > > >
> > > > > 9113.2 Should RemoteLogSegmentMetadataUpdate include a leadeEpoch
> > field
> > > > > since all other update events have leaderEpoch?
> > > > >
> > > > > +1 to have that,  updated the KIP.
> > > > >
> > > > > 9113.3 Could we rename RemotePartitionState to
> > RemotePartitionDeleteState
> > > > > to make it clear this is for deletion?
> > > > >
> > > > > Sure, updated the KIP.
> > > > >
> > > > > 9113.4 Could we rename RemoteLogState to RemoteLogSegmentState to
> > make it
> > > > > clear this is for segment?
> > > > >
> > > > > Sure, Updated the KIP.
> > > > >
> > > > > 9114.Upgrade:
> > > > > 9114.1 It seems that we require message format > 0.11 for turning on
> > the
> > > > > remote store feature.
> > > > >
> > > > > 9114.2 It's not clear to me why remote.log.storage.system.enable
> > needs to
> > > > > be set to true before bumping up inter.broker.protocol.version.
> > > > >
> > > > > Agree that based on our discussion, this is not required. Upgrade
> > > > > notes is updated.
> > > > >
> > > > > 9114.3 "If the topic-id is not received in the LeaderAndIsr request
> > then
> > > > > remote log storage will not start. But it will log an error message
> > in
> > > > the
> > > > > log. One way to address this is to do a rolling restart of that
> > broker,
> > > > so
> > > > > that the leader will be moved to another broker and the controller
> > will
> > > > > send LeaderAndIsr with the registered topic-id." Why is this needed?
> > With
> > > > > KIP-516, after upgrading to the latest protocol, topicIds are auto
> > > > created.
> > > > >
> > > > > I thought there may be edge cases of not receiving topic-id but you
> > > > > clarified in the meeting that won’t be the case. I agree that it is
> > > > > not needed.
> > > > >
> > > > > 9115. testing: Could you comment on how we plan to do integration and
> > > > > system tests? Do we plan to include, for example, an in-memory
> > > > > implementation of RSM?
> > > > >
> > > > > For integration tests, we can have file based RSM that we have. For
> > > > > system tests, we can have a single node HDFS cluster in one of the
> > > > > containers and use HDFS RSM implementation.
> > > > >
> > > > > 9116. There is still a todo for the message formatter.
> > > > >
> > > > > Updated the KIP with the format.
> > > > >
> > > > >
> > > > > Satish.
> > > > >
> > > > >
> > > > > On Tue, 12 Jan 2021 at 07:07, Jun Rao <ju...@confluent.io> wrote:
> > > > > >
> > > > > > Hi, Satish,
> > > > > >
> > > > > > Thanks for the reply. A few more followup comments.
> > > > > >
> > > > > > 6000. Since we are returning new error codes, we need to bump up
> > the
> > > > > > protocol version for Fetch request. Also, it will be useful to
> > document
> > > > > all
> > > > > > new error codes and whether they are retriable or not.
> > > > > > This previous comment doesn't seem to be addressed.
> > > > > >
> > > > > > 9110. flat_file_format: Could you define the serialized
> > representation
> > > > > for
> > > > > > each field in the header?
> > > > > >
> > > > > > 9111. RPM has the following 2 steps.
> > > > > > "1. The controller publishes delete_partition_marked event to say
> > that
> > > > > the
> > > > > > partition is marked for deletion. There can be multiple events
> > > > published
> > > > > > when the controller restarts or failover and this event will be
> > > > > > deduplicated by RPM.
> > > > > > 2. RPM receives the delete_partition_marked and processes it if it
> > is
> > > > not
> > > > > > yet processed earlier."
> > > > > > What triggers RPM to read __remote_log_metadata? Is RPM part of the
> > > > > default
> > > > > > RLMM implementation or is it meant for any RLMM implementation?
> > > > > >
> > > > > > 9112. remote.log.manager.task.retry.backoff.ms: It would be
> > useful to
> > > > > make
> > > > > > it clear in the comment that this is for the initial retry backoff.
> > > > > >
> > > > > > 9113. RLMM:
> > > > > > 9113.1 updateRemoteLogSegmentMetadata(): This comment needs to be
> > > > > updated.
> > > > > > 9113.2 Should RemoteLogSegmentMetadataUpdate include a leadeEpoch
> > field
> > > > > > since all other update events have leaderEpoch?
> > > > > > 9113.3 Could we rename RemotePartitionState to
> > > > RemotePartitionDeleteState
> > > > > > to make it clear this is for deletion?
> > > > > > 9113.4 Could we rename RemoteLogState to RemoteLogSegmentState to
> > make
> > > > it
> > > > > > clear this is for segment?
> > > > > >
> > > > > > 9114.Upgrade:
> > > > > > 9114.1 It seems that we require message format > 0.11 for turning
> > on
> > > > the
> > > > > > remote store feature.
> > > > > > 9114.2 It's not clear to me why remote.log.storage.system.enable
> > needs
> > > > to
> > > > > > be set to true before bumping up inter.broker.protocol.version.
> > > > > > 9114.3 "If the topic-id is not received in the LeaderAndIsr request
> > > > then
> > > > > > remote log storage will not start. But it will log an error
> > message in
> > > > > the
> > > > > > log. One way to address this is to do a rolling restart of that
> > broker,
> > > > > so
> > > > > > that the leader will be moved to another broker and the controller
> > will
> > > > > > send LeaderAndIsr with the registered topic-id." Why is this
> > needed?
> > > > With
> > > > > > KIP-516, after upgrading to the latest protocol, topicIds are auto
> > > > > created.
> > > > > >
> > > > > > 9115. testing: Could you comment on how we plan to do integration
> > and
> > > > > > system tests? Do we plan to include, for example, an in-memory
> > > > > > implementation of RSM?
> > > > > >
> > > > > > 9116. There is still a todo for the message formatter.
> > > > > >
> > > > > > Jun
> > > > > >
> > > > > > On Sat, Jan 9, 2021 at 2:04 AM Satish Duggana <
> > > > satish.duggana@gmail.com>
> > > > > > wrote:
> > > > > >
> > > > > > > Hi Jun,
> > > > > > > Thanks for your comments. Please find the inline replies below.
> > > > > > >
> > > > > > > 6022. For packages used for server plugins, the convention is to
> > > > > > > use org.apache.kafka.server. See java-based Authorizer as an
> > example.
> > > > > > >
> > > > > > > Sure, ‘org.apache.kafka.common.log.remote.storage’ renamed to
> > > > > > > ‘org.apache.kafka.server.log.remote.storage’.  Updated in the
> > KIP.
> > > > > > >
> > > > > > > 9100. Do we need DeletePartitionStateRecord in flat_file_format?
> > The
> > > > > flat
> > > > > > > file captures the state of the remote segments. After a
> > partition is
> > > > > > > deleted, it seems that we just need to remove the partitions's
> > remote
> > > > > > > segments from the flat file.
> > > > > > >
> > > > > > > DeletePartitionState might not yet have been processed by RPM
> > and not
> > > > > > > completed. We  will not have  that in flat  file format  once it
> > > > > > > reaches DELETE_PARTITION_FINISHED state.
> > > > > > >
> > > > > > > 9101. Upgrade: It will be useful to allow direct upgrade from an
> > old
> > > > > > > version. It seems that's doable. One can just do the normal
> > upgrade
> > > > > first
> > > > > > > and wait enough time (for producer snapshots to be built), and
> > then
> > > > > enable
> > > > > > > remote storage.
> > > > > > >
> > > > > > > Upgrade notes updates in the KIP.
> > > > > > >
> > > > > > > 9102. RemotePartitionRemover(RPM) process: Is it true that RPM
> > starts
> > > > > > > tracking the remote segments when
> > RLMM.onPartitionLeadershipChanges()
> > > > > is
> > > > > > > called with the broker being the leader for __remote_log_metadata
> > > > > > > partition? If so, could we document it?
> > > > > > >
> > > > > > > The current plan is to have that as part of RLMM and RPM uses
> > that to
> > > > > > > get the remote segments list. I will add this detail in the
> > > > respective
> > > > > > > sections.
> > > > > > >
> > > > > > > Satish.
> > > > > > >
> > > > > > > On Wed, 16 Dec 2020 at 23:55, Jun Rao <ju...@confluent.io> wrote:
> > > > > > > >
> > > > > > > > Hi, Satish,
> > > > > > > >
> > > > > > > > Thanks for the reply. A few more followup comments.
> > > > > > > >
> > > > > > > > 6022. For packages used for server plugins, the convention is
> > to
> > > > > > > > use org.apache.kafka.server. See java-based Authorizer as an
> > > > example.
> > > > > > > >
> > > > > > > > 9100. Do we need DeletePartitionStateRecord in
> > flat_file_format?
> > > > The
> > > > > flat
> > > > > > > > file captures the state of the remote segments. After a
> > partition
> > > > is
> > > > > > > > deleted, it seems that we just need to remove the partitions's
> > > > remote
> > > > > > > > segments from the flat file.
> > > > > > > >
> > > > > > > > 9101. Upgrade: It will be useful to allow direct upgrade from
> > an
> > > > old
> > > > > > > > version. It seems that's doable. One can just do the normal
> > upgrade
> > > > > first
> > > > > > > > and wait enough time (for producer snapshots to be built), and
> > then
> > > > > > > enable
> > > > > > > > remote storage.
> > > > > > > >
> > > > > > > > 9102. RemotePartitionRemover(RPM) process: Is it true that RPM
> > > > starts
> > > > > > > > tracking the remote segments when
> > > > > RLMM.onPartitionLeadershipChanges() is
> > > > > > > > called with the broker being the leader for
> > __remote_log_metadata
> > > > > > > > partition? If so, could we document it?
> > > > > > > >
> > > > > > > > Jun
> > > > > > > >
> > > > > > > > On Tue, Dec 15, 2020 at 8:47 AM Kowshik Prakasam <
> > > > > kprakasam@confluent.io
> > > > > > > >
> > > > > > > > wrote:
> > > > > > > >
> > > > > > > > > Hi Satish,
> > > > > > > > >
> > > > > > > > > Thanks for the updates! A few more comments below.
> > > > > > > > >
> > > > > > > > > 9001. Under the "Upgrade" section, there is a line
> > mentioning:
> > > > > > > "Upgrade the
> > > > > > > > > existing Kafka cluster to 2.7 version and allow this to run
> > for
> > > > > the log
> > > > > > > > > retention of user topics that you want to enable tiered
> > storage.
> > > > > This
> > > > > > > will
> > > > > > > > > allow all the topics to have the producer snapshots
> > generated for
> > > > > each
> > > > > > > log
> > > > > > > > > segment." -- Which associated change in AK were you
> > referring to
> > > > > here?
> > > > > > > Is
> > > > > > > > > it: https://github.com/apache/kafka/pull/7929 ? It seems
> > like I
> > > > > don't
> > > > > > > see
> > > > > > > > > it in the 2.7 release branch yet, here is the link:
> > > > > > > > > https://github.com/apache/kafka/commits/2.7.
> > > > > > > > >
> > > > > > > > > 9002. Under the "Upgrade" section, the configuration
> > mentioned is
> > > > > > > > > 'remote.log.storage.system.enable'. However, under "Public
> > > > > Interfaces"
> > > > > > > > > section the corresponding configuration is
> > > > > > > 'remote.storage.system.enable'.
> > > > > > > > > Could we use the same one in both, maybe
> > > > > > > > > 'remote.log.storage.system.enable'?
> > > > > > > > >
> > > > > > > > > 9003. Under "Per Topic Configuration", the KIP recommends
> > setting
> > > > > > > > > 'remote.log.storage.enable' to true at a per-topic level. It
> > will
> > > > > be
> > > > > > > useful
> > > > > > > > > to add a line that if the user wants to enable it for all
> > topics,
> > > > > then
> > > > > > > they
> > > > > > > > > should be able to set the cluster-wide default to true.
> > Also, it
> > > > > will
> > > > > > > be
> > > > > > > > > useful to mention that the KIP currently does not support
> > setting
> > > > > it to
> > > > > > > > > false (after it is set to true), and add that to the future
> > work
> > > > > > > section.
> > > > > > > > >
> > > > > > > > > 9004. Under "Committed offsets file format", the sample
> > provided
> > > > > shows
> > > > > > > > > partition number and offset. Is the topic name required for
> > > > > identifying
> > > > > > > > > which topic the partitions belong to?
> > > > > > > > >
> > > > > > > > > 9005. Under "Internal flat-file store format of remote log
> > > > > metadata",
> > > > > > > it
> > > > > > > > > seems useful to specify both topic name and topic ID for
> > > > debugging
> > > > > > > > > purposes.
> > > > > > > > >
> > > > > > > > > 9006. Under "Internal flat-file store format of remote log
> > > > > metadata",
> > > > > > > the
> > > > > > > > > description of "metadata-topic-offset" currently says
> > "offset of
> > > > > the
> > > > > > > remote
> > > > > > > > > log metadata topic from which this topic partition's remote
> > log
> > > > > > > metadata is
> > > > > > > > > fetched." Just for the wording, perhaps you meant to refer
> > to the
> > > > > > > offset
> > > > > > > > > upto which the file has been committed? i.e. "offset of the
> > > > remote
> > > > > log
> > > > > > > > > metadata topic upto which this topic partition's remote log
> > > > > metadata
> > > > > > > has
> > > > > > > > > been committed into this file."
> > > > > > > > >
> > > > > > > > > 9007. Under "Internal flat-file store format of remote log
> > > > > metadata",
> > > > > > > the
> > > > > > > > > schema of the payload (i.e. beyond the header) seems to
> > contain
> > > > the
> > > > > > > events
> > > > > > > > > from the metadata topic. It seems useful to instead persist
> > the
> > > > > > > > > representation of the materialized state of the events, so
> > that
> > > > > for the
> > > > > > > > > same segment only the latest state is stored. Besides
> > reducing
> > > > > storage
> > > > > > > > > footprint, this also is likely to relate directly with the
> > > > > in-memory
> > > > > > > > > representation of the RLMM cache (which probably is some
> > kind of
> > > > a
> > > > > Map
> > > > > > > with
> > > > > > > > > key being segment ID and value being the segment state), so
> > > > > recovery
> > > > > > > from
> > > > > > > > > disk will be straightforward.
> > > > > > > > >
> > > > > > > > > 9008. Under "Topic deletion lifecycle", step (1), it will be
> > > > > useful to
> > > > > > > > > mention when in the deletion flow does the controller
> > publish the
> > > > > > > > > delete_partition_marked event to say that the partition is
> > marked
> > > > > for
> > > > > > > > > deletion?
> > > > > > > > >
> > > > > > > > > 9009. There are ~4 TODOs in the KIP. Could you please address
> > > > > these or
> > > > > > > > > remove them?
> > > > > > > > >
> > > > > > > > > 9010. There is a reference to a Google doc on the KIP which
> > was
> > > > > used
> > > > > > > > > earlier for discussions. Please could you remove the
> > reference,
> > > > > since
> > > > > > > the
> > > > > > > > > KIP is the source of the truth?
> > > > > > > > >
> > > > > > > > > 9011. This feedback is from an earlier comment. In the
> > > > > > > RemoteStorageManager
> > > > > > > > > interface, there is an API defined for each file type. For
> > > > example,
> > > > > > > > > fetchOffsetIndex, fetchTimestampIndex etc. To avoid the
> > > > > duplication,
> > > > > > > I'd
> > > > > > > > > suggest we can instead have a FileType enum and a common get
> > API
> > > > > based
> > > > > > > on
> > > > > > > > > the FileType. What do you think?
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > Cheers,
> > > > > > > > > Kowshik
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > On Mon, Dec 14, 2020 at 11:07 AM Satish Duggana <
> > > > > > > satish.duggana@gmail.com>
> > > > > > > > > wrote:
> > > > > > > > >
> > > > > > > > > > Hi Jun,
> > > > > > > > > > Thanks for your comments. Please go through the inline
> > replies.
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > 5102.2: It seems that both positions can just be int.
> > Another
> > > > > option
> > > > > > > is
> > > > > > > > > to
> > > > > > > > > > have two methods. Would it be clearer?
> > > > > > > > > >
> > > > > > > > > >     InputStream
> > fetchLogSegmentData(RemoteLogSegmentMetadata
> > > > > > > > > > remoteLogSegmentMetadata,  int startPosition)
> > > > > > > > > throwsRemoteStorageException;
> > > > > > > > > >
> > > > > > > > > >     InputStream
> > fetchLogSegmentData(RemoteLogSegmentMetadata
> > > > > > > > > > remoteLogSegmentMetadata, int startPosition, int
> > endPosition)
> > > > > throws
> > > > > > > > > > RemoteStorageException;
> > > > > > > > > >
> > > > > > > > > > That makes sense to me, updated the KIP.
> > > > > > > > > >
> > > > > > > > > > 6003: Could you also update the javadoc for the return
> > value?
> > > > > > > > > >
> > > > > > > > > > Updated.
> > > > > > > > > >
> > > > > > > > > > 6020: local.log.retention.bytes: Should it default to
> > > > > > > log.retention.bytes
> > > > > > > > > > to be consistent with local.log.retention.ms?
> > > > > > > > > >
> > > > > > > > > > Yes, it can be defaulted to log.retention.bytes.
> > > > > > > > > >
> > > > > > > > > > 6021: Could you define TopicIdPartition?
> > > > > > > > > >
> > > > > > > > > > Added TopicIdPartition in the KIP.
> > > > > > > > > >
> > > > > > > > > > 6022: For all public facing classes, could you specify the
> > > > > package
> > > > > > > name?
> > > > > > > > > >
> > > > > > > > > > Updated.
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > Thanks,
> > > > > > > > > > Satish.
> > > > > > > > > >
> > > > > > > > > > On Tue, Dec 8, 2020 at 12:59 AM Jun Rao <ju...@confluent.io>
> > > > > wrote:
> > > > > > > > > > >
> > > > > > > > > > > Hi, Satish,
> > > > > > > > > > >
> > > > > > > > > > > Thanks for the reply. A few more comments below.
> > > > > > > > > > >
> > > > > > > > > > > 5102.2: It seems that both positions can just be int.
> > Another
> > > > > > > option is
> > > > > > > > > > to
> > > > > > > > > > > have two methods. Would it be clearer?
> > > > > > > > > > >
> > > > > > > > > > >     InputStream
> > fetchLogSegmentData(RemoteLogSegmentMetadata
> > > > > > > > > > > remoteLogSegmentMetadata,
> > > > > > > > > > >                                     int startPosition)
> > throws
> > > > > > > > > > > RemoteStorageException;
> > > > > > > > > > >
> > > > > > > > > > >     InputStream
> > fetchLogSegmentData(RemoteLogSegmentMetadata
> > > > > > > > > > > remoteLogSegmentMetadata,
> > > > > > > > > > >                                     int startPosition,
> > int
> > > > > > > endPosition)
> > > > > > > > > > > throws RemoteStorageException;
> > > > > > > > > > >
> > > > > > > > > > > 6003: Could you also update the javadoc for the return
> > value?
> > > > > > > > > > >
> > > > > > > > > > > 6010: What kind of tiering throughput have you seen with
> > 5
> > > > > threads?
> > > > > > > > > > >
> > > > > > > > > > > 6020: local.log.retention.bytes: Should it default to
> > > > > > > > > log.retention.bytes
> > > > > > > > > > > to be consistent with local.log.retention.ms?
> > > > > > > > > > >
> > > > > > > > > > > 6021: Could you define TopicIdPartition?
> > > > > > > > > > >
> > > > > > > > > > > 6022: For all public facing classes, could you specify
> > the
> > > > > package
> > > > > > > > > name?
> > > > > > > > > > >
> > > > > > > > > > > It seems that you already added the topicId support. Two
> > > > other
> > > > > > > > > remaining
> > > > > > > > > > > items are (a) the format of local tier metadata storage
> > and
> > > > (b)
> > > > > > > > > upgrade.
> > > > > > > > > > >
> > > > > > > > > > > Jun
> > > > > > > > > > >
> > > > > > > > > > > On Mon, Dec 7, 2020 at 8:56 AM Satish Duggana <
> > > > > > > > > satish.duggana@gmail.com>
> > > > > > > > > > > wrote:
> > > > > > > > > > >
> > > > > > > > > > > > Hi Jun,
> > > > > > > > > > > > Thanks for your comments. Please find the inline
> > replies
> > > > > below.
> > > > > > > > > > > >
> > > > > > > > > > > > >605.2 It's rare for the follower to need the remote
> > data.
> > > > > So,
> > > > > > > the
> > > > > > > > > > current
> > > > > > > > > > > > approach is fine too. Could you document the process of
> > > > > > > rebuilding
> > > > > > > > > the
> > > > > > > > > > > > producer state since we can't simply trim the
> > producerState
> > > > > to an
> > > > > > > > > > offset in
> > > > > > > > > > > > the middle of a segment.
> > > > > > > > > > > >
> > > > > > > > > > > > Will clarify in the KIP.
> > > > > > > > > > > >
> > > > > > > > > > > > >5102.2 Would it be clearer to make startPosiont long
> > and
> > > > > > > endPosition
> > > > > > > > > > of
> > > > > > > > > > > > Optional<Long>?
> > > > > > > > > > > >
> > > > > > > > > > > > We will have arg checks with respective validation. It
> > is
> > > > > not a
> > > > > > > good
> > > > > > > > > > > > practice to have arguments with optional as mentioned
> > here.
> > > > > > > > > > > > https://rules.sonarsource.com/java/RSPEC-3553
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > >5102.5 LogSegmentData still has leaderEpochIndex as
> > File
> > > > > > > instead of
> > > > > > > > > > > > ByteBuffer.
> > > > > > > > > > > >
> > > > > > > > > > > > Updated.
> > > > > > > > > > > >
> > > > > > > > > > > > >5102.7 Could you define all public methods for
> > > > > LogSegmentData?
> > > > > > > > > > > >
> > > > > > > > > > > > Updated.
> > > > > > > > > > > >
> > > > > > > > > > > > >5103.5 Could you change the reference to
> > > > > > > rlm_process_interval_ms and
> > > > > > > > > > > > rlm_retry_interval_ms to the new config names? Also,
> > the
> > > > > retry
> > > > > > > > > interval
> > > > > > > > > > > > config seems still missing. It would be useful to
> > support
> > > > > > > exponential
> > > > > > > > > > > > backoff with the retry interval config.
> > > > > > > > > > > >
> > > > > > > > > > > > Good point. We wanted the retry with truncated
> > exponential
> > > > > > > backoff,
> > > > > > > > > > > > updated the KIP.
> > > > > > > > > > > >
> > > > > > > > > > > > >5111. "RLM follower fetches the earliest offset for
> > the
> > > > > earliest
> > > > > > > > > > leader
> > > > > > > > > > > > epoch by calling RLMM.earliestLogOffset(TopicPartition
> > > > > > > > > topicPartition,
> > > > > > > > > > int
> > > > > > > > > > > > leaderEpoch) and updates that as the log start offset."
> > > > This
> > > > > > > text is
> > > > > > > > > > still
> > > > > > > > > > > > there. Also, could we remove earliestLogOffset() from
> > RLMM?
> > > > > > > > > > > >
> > > > > > > > > > > > Updated.
> > > > > > > > > > > >
> > > > > > > > > > > > >5115. There are still references to "remote log
> > cleaners".
> > > > > > > > > > > >
> > > > > > > > > > > > Updated.
> > > > > > > > > > > >
> > > > > > > > > > > > >6000. Since we are returning new error codes, we need
> > to
> > > > > bump
> > > > > > > up the
> > > > > > > > > > > > protocol version for Fetch request. Also, it will be
> > useful
> > > > > to
> > > > > > > > > > document all
> > > > > > > > > > > > new error codes and whether they are retriable or not.
> > > > > > > > > > > >
> > > > > > > > > > > > Sure, we will add that in the KIP.
> > > > > > > > > > > >
> > > > > > > > > > > > >6001. public Map<Long, Long> segmentLeaderEpochs():
> > > > > Currently,
> > > > > > > > > > leaderEpoch
> > > > > > > > > > > > is int32 instead of long.
> > > > > > > > > > > >
> > > > > > > > > > > > Updated.
> > > > > > > > > > > >
> > > > > > > > > > > > >6002. Is RemoteLogSegmentMetadata.markedForDeletion()
> > > > needed
> > > > > > > given
> > > > > > > > > > > > RemoteLogSegmentMetadata.state()?
> > > > > > > > > > > >
> > > > > > > > > > > > No, it is fixed.
> > > > > > > > > > > >
> > > > > > > > > > > > >6003. RemoteLogSegmentMetadata
> > > > > > > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > > > > topicPartition, long offset, int epochForOffset):
> > Should
> > > > this
> > > > > > > return
> > > > > > > > > > > > Optional<RemoteLogSegmentMetadata>?
> > > > > > > > > > > >
> > > > > > > > > > > > That makes sense, updated.
> > > > > > > > > > > >
> > > > > > > > > > > > >6005. RemoteLogState: It seems it's better to split it
> > > > > between
> > > > > > > > > > > > DeletePartitionUpdate and
> > RemoteLogSegmentMetadataUpdate
> > > > > since
> > > > > > > the
> > > > > > > > > > states
> > > > > > > > > > > > are never shared between the two use cases.
> > > > > > > > > > > >
> > > > > > > > > > > > Agree with that, updated.
> > > > > > > > > > > >
> > > > > > > > > > > > >6006. RLMM.onPartitionLeadershipChanges(): This may
> > be ok.
> > > > > > > However,
> > > > > > > > > > is it
> > > > > > > > > > > > ture that other than the metadata topic, RLMM just
> > needs to
> > > > > know
> > > > > > > > > > whether
> > > > > > > > > > > > there is a replica assigned to this broker and doesn't
> > need
> > > > > to
> > > > > > > know
> > > > > > > > > > whether
> > > > > > > > > > > > the replica is the leader or the follower?
> > > > > > > > > > > >
> > > > > > > > > > > > That may be true. If the implementation does not need
> > that,
> > > > > it
> > > > > > > can
> > > > > > > > > > > > ignore the information in the callback.
> > > > > > > > > > > >
> > > > > > > > > > > > >6007: "Handle expired remote segments (leader and
> > > > > follower)":
> > > > > > > Why is
> > > > > > > > > > this
> > > > > > > > > > > > needed in both the leader and the follower?
> > > > > > > > > > > >
> > > > > > > > > > > > Updated.
> > > > > > > > > > > >
> > > > > > > > > > > > >6008.       "name": "SegmentSizeInBytes",
> > > > > > > > > > > >                 "type": "int64",
> > > > > > > > > > > > The segment size can just be int32.
> > > > > > > > > > > >
> > > > > > > > > > > > Updated.
> > > > > > > > > > > >
> > > > > > > > > > > > >6009. For the record format in the log, it seems that
> > we
> > > > > need
> > > > > > > to add
> > > > > > > > > > > > record
> > > > > > > > > > > > type and record version before the serialized bytes.
> > We can
> > > > > > > follow
> > > > > > > > > the
> > > > > > > > > > > > convention used in
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > >
> > > > >
> > > >
> > https://cwiki.apache.org/confluence/display/KAFKA/KIP-631%3A+The+Quorum-based+Kafka+Controller#KIP631:TheQuorumbasedKafkaController-RecordFormats
> > > > > > > > > > > >
> > > > > > > > > > > > Yes, KIP already mentions that these are serialized
> > before
> > > > > the
> > > > > > > > > payload
> > > > > > > > > > > > as below. We will mention explicitly that these two are
> > > > > written
> > > > > > > > > before
> > > > > > > > > > > > the data is written.
> > > > > > > > > > > >
> > > > > > > > > > > > RLMM instance on broker publishes the message to the
> > topic
> > > > > with
> > > > > > > key
> > > > > > > > > as
> > > > > > > > > > > > null and value with the below format.
> > > > > > > > > > > >
> > > > > > > > > > > > type      : unsigned var int, represents the value
> > type.
> > > > This
> > > > > > > value
> > > > > > > > > is
> > > > > > > > > > > > 'apikey' as mentioned in the schema.
> > > > > > > > > > > > version : unsigned var int, the 'version' number of the
> > > > type
> > > > > as
> > > > > > > > > > > > mentioned in the schema.
> > > > > > > > > > > > data      : record payload in kafka protocol message
> > > > format.
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > >6010. remote.log.manager.thread.pool.size: The default
> > > > > value is
> > > > > > > 10.
> > > > > > > > > > This
> > > > > > > > > > > > might be too high when enabling the tiered feature for
> > the
> > > > > first
> > > > > > > > > time.
> > > > > > > > > > > > Since there are lots of segments that need to be tiered
> > > > > > > initially, a
> > > > > > > > > > large
> > > > > > > > > > > > number of threads could overwhelm the broker.
> > > > > > > > > > > >
> > > > > > > > > > > > Is the default value 5 reasonable?
> > > > > > > > > > > >
> > > > > > > > > > > > 6011. "The number of milli seconds to keep the local
> > log
> > > > > segment
> > > > > > > > > > before it
> > > > > > > > > > > > gets deleted. If not set, the value in
> > > > > `log.retention.minutes` is
> > > > > > > > > > used. If
> > > > > > > > > > > > set to -1, no time limit is applied." We should use
> > > > > > > log.retention.ms
> > > > > > > > > > > > instead of log.retention.minutes.
> > > > > > > > > > > > Nice typo catch. Updated the KIP.
> > > > > > > > > > > >
> > > > > > > > > > > > Thanks,
> > > > > > > > > > > > Satish.
> > > > > > > > > > > >
> > > > > > > > > > > > On Thu, Dec 3, 2020 at 8:03 AM Jun Rao <
> > jun@confluent.io>
> > > > > wrote:
> > > > > > > > > > > > >
> > > > > > > > > > > > > Hi, Satish,
> > > > > > > > > > > > >
> > > > > > > > > > > > > Thanks for the updated KIP. A few more comments
> > below.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 605.2 It's rare for the follower to need the remote
> > data.
> > > > > So,
> > > > > > > the
> > > > > > > > > > current
> > > > > > > > > > > > > approach is fine too. Could you document the process
> > of
> > > > > > > rebuilding
> > > > > > > > > > the
> > > > > > > > > > > > > producer state since we can't simply trim the
> > > > > producerState to
> > > > > > > an
> > > > > > > > > > offset
> > > > > > > > > > > > in
> > > > > > > > > > > > > the middle of a segment.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5102.2 Would it be clearer to make startPosiont long
> > and
> > > > > > > > > endPosition
> > > > > > > > > > of
> > > > > > > > > > > > > Optional<Long>?
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5102.5 LogSegmentData still has leaderEpochIndex as
> > File
> > > > > > > instead of
> > > > > > > > > > > > > ByteBuffer.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5102.7 Could you define all public methods for
> > > > > LogSegmentData?
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5103.5 Could you change the reference to
> > > > > > > rlm_process_interval_ms
> > > > > > > > > and
> > > > > > > > > > > > > rlm_retry_interval_ms to the new config names? Also,
> > the
> > > > > retry
> > > > > > > > > > interval
> > > > > > > > > > > > > config seems still missing. It would be useful to
> > support
> > > > > > > > > exponential
> > > > > > > > > > > > > backoff with the retry interval config.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5111. "RLM follower fetches the earliest offset for
> > the
> > > > > > > earliest
> > > > > > > > > > leader
> > > > > > > > > > > > > epoch by calling
> > RLMM.earliestLogOffset(TopicPartition
> > > > > > > > > > topicPartition,
> > > > > > > > > > > > int
> > > > > > > > > > > > > leaderEpoch) and updates that as the log start
> > offset."
> > > > > This
> > > > > > > text
> > > > > > > > > is
> > > > > > > > > > > > still
> > > > > > > > > > > > > there. Also, could we remove earliestLogOffset() from
> > > > RLMM?
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5115. There are still references to "remote log
> > > > cleaners".
> > > > > > > > > > > > >
> > > > > > > > > > > > > 6000. Since we are returning new error codes, we
> > need to
> > > > > bump
> > > > > > > up
> > > > > > > > > the
> > > > > > > > > > > > > protocol version for Fetch request. Also, it will be
> > > > > useful to
> > > > > > > > > > document
> > > > > > > > > > > > all
> > > > > > > > > > > > > new error codes and whether they are retriable or
> > not.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 6001. public Map<Long, Long> segmentLeaderEpochs():
> > > > > Currently,
> > > > > > > > > > > > leaderEpoch
> > > > > > > > > > > > > is int32 instead of long.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 6002. Is RemoteLogSegmentMetadata.markedForDeletion()
> > > > > needed
> > > > > > > given
> > > > > > > > > > > > > RemoteLogSegmentMetadata.state()?
> > > > > > > > > > > > >
> > > > > > > > > > > > > 6003. RemoteLogSegmentMetadata
> > > > > > > > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > > > > > topicPartition, long offset, int epochForOffset):
> > Should
> > > > > this
> > > > > > > > > return
> > > > > > > > > > > > > Optional<RemoteLogSegmentMetadata>?
> > > > > > > > > > > > >
> > > > > > > > > > > > > 6004. DeletePartitionUpdate.epoch(): It would be
> > useful
> > > > to
> > > > > > > pick a
> > > > > > > > > > more
> > > > > > > > > > > > > indicative name so that people understand what epoch
> > this
> > > > > is.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 6005. RemoteLogState: It seems it's better to split
> > it
> > > > > between
> > > > > > > > > > > > > DeletePartitionUpdate and
> > RemoteLogSegmentMetadataUpdate
> > > > > since
> > > > > > > the
> > > > > > > > > > states
> > > > > > > > > > > > > are never shared between the two use cases.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 6006. RLMM.onPartitionLeadershipChanges(): This may
> > be
> > > > ok.
> > > > > > > However,
> > > > > > > > > > is it
> > > > > > > > > > > > > ture that other than the metadata topic, RLMM just
> > needs
> > > > to
> > > > > > > know
> > > > > > > > > > whether
> > > > > > > > > > > > > there is a replica assigned to this broker and
> > doesn't
> > > > > need to
> > > > > > > know
> > > > > > > > > > > > whether
> > > > > > > > > > > > > the replica is the leader or the follower?
> > > > > > > > > > > > >
> > > > > > > > > > > > > 6007: "Handle expired remote segments (leader and
> > > > > follower)":
> > > > > > > Why
> > > > > > > > > is
> > > > > > > > > > this
> > > > > > > > > > > > > needed in both the leader and the follower?
> > > > > > > > > > > > >
> > > > > > > > > > > > > 6008.       "name": "SegmentSizeInBytes",
> > > > > > > > > > > > >                 "type": "int64",
> > > > > > > > > > > > > The segment size can just be int32.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 6009. For the record format in the log, it seems
> > that we
> > > > > need
> > > > > > > to
> > > > > > > > > add
> > > > > > > > > > > > record
> > > > > > > > > > > > > type and record version before the serialized bytes.
> > We
> > > > can
> > > > > > > follow
> > > > > > > > > > the
> > > > > > > > > > > > > convention used in
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > >
> > > > >
> > > >
> > https://cwiki.apache.org/confluence/display/KAFKA/KIP-631%3A+The+Quorum-based+Kafka+Controller#KIP631:TheQuorumbasedKafkaController-RecordFormats
> > > > > > > > > > > > > .
> > > > > > > > > > > > >
> > > > > > > > > > > > > 6010. remote.log.manager.thread.pool.size: The
> > default
> > > > > value
> > > > > > > is 10.
> > > > > > > > > > This
> > > > > > > > > > > > > might be too high when enabling the tiered feature
> > for
> > > > the
> > > > > > > first
> > > > > > > > > > time.
> > > > > > > > > > > > > Since there are lots of segments that need to be
> > tiered
> > > > > > > initially,
> > > > > > > > > a
> > > > > > > > > > > > large
> > > > > > > > > > > > > number of threads could overwhelm the broker.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 6011. "The number of milli seconds to keep the local
> > log
> > > > > > > segment
> > > > > > > > > > before
> > > > > > > > > > > > it
> > > > > > > > > > > > > gets deleted. If not set, the value in
> > > > > `log.retention.minutes`
> > > > > > > is
> > > > > > > > > > used.
> > > > > > > > > > > > If
> > > > > > > > > > > > > set to -1, no time limit is applied." We should use
> > > > > > > > > log.retention.ms
> > > > > > > > > > > > > instead of log.retention.minutes.
> > > > > > > > > > > > >
> > > > > > > > > > > > > Jun
> > > > > > > > > > > > >
> > > > > > > > > > > > > On Tue, Dec 1, 2020 at 2:42 AM Satish Duggana <
> > > > > > > > > > satish.duggana@gmail.com>
> > > > > > > > > > > > > wrote:
> > > > > > > > > > > > >
> > > > > > > > > > > > > > Hi,
> > > > > > > > > > > > > > We updated the KIP with the points mentioned in the
> > > > > earlier
> > > > > > > mail
> > > > > > > > > > > > > > except for KIP-516 related changes. You can go
> > through
> > > > > them
> > > > > > > and
> > > > > > > > > > let us
> > > > > > > > > > > > > > know if you have any comments. We will update the
> > KIP
> > > > > with
> > > > > > > the
> > > > > > > > > > > > > > remaining todo items and KIP-516 related changes
> > by end
> > > > > of
> > > > > > > this
> > > > > > > > > > > > > > week(5th Dec).
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > Satish.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > On Tue, Nov 10, 2020 at 8:26 PM Satish Duggana <
> > > > > > > > > > > > satish.duggana@gmail.com>
> > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Hi Jun,
> > > > > > > > > > > > > > > Thanks for your comments. Please find the inline
> > > > > replies
> > > > > > > below.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 605.2 "Build the local leader epoch cache by
> > cutting
> > > > > the
> > > > > > > leader
> > > > > > > > > > epoch
> > > > > > > > > > > > > > > sequence received from remote storage to [LSO,
> > > > ELO]." I
> > > > > > > > > > mentioned an
> > > > > > > > > > > > > > issue
> > > > > > > > > > > > > > > earlier. Suppose the leader's local start offset
> > is
> > > > > 100.
> > > > > > > The
> > > > > > > > > > follower
> > > > > > > > > > > > > > finds
> > > > > > > > > > > > > > > a remote segment covering offset range [80,
> > 120). The
> > > > > > > > > > producerState
> > > > > > > > > > > > with
> > > > > > > > > > > > > > > this remote segment is up to offset 120. To trim
> > the
> > > > > > > > > > producerState to
> > > > > > > > > > > > > > > offset 100 requires more work since one needs to
> > > > > download
> > > > > > > the
> > > > > > > > > > > > previous
> > > > > > > > > > > > > > > producerState up to offset 80 and then replay the
> > > > > messages
> > > > > > > from
> > > > > > > > > > 80 to
> > > > > > > > > > > > > > 100.
> > > > > > > > > > > > > > > It seems that it's simpler in this case for the
> > > > > follower
> > > > > > > just
> > > > > > > > > to
> > > > > > > > > > > > take the
> > > > > > > > > > > > > > > remote segment as it is and start fetching from
> > > > offset
> > > > > 120.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > We chose that approach to avoid any edge cases
> > here.
> > > > It
> > > > > > > may be
> > > > > > > > > > > > > > > possible that the remote log segment that is
> > received
> > > > > may
> > > > > > > not
> > > > > > > > > > have
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > same leader epoch sequence from 100-120 as it
> > > > contains
> > > > > on
> > > > > > > the
> > > > > > > > > > > > > > > leader(this can happen due to unclean leader).
> > It is
> > > > > safe
> > > > > > > to
> > > > > > > > > > start
> > > > > > > > > > > > > > > from what the leader returns here.Another way is
> > to
> > > > > find
> > > > > > > the
> > > > > > > > > > remote
> > > > > > > > > > > > > > > log segment
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5016. Just to echo what Kowshik was saying. It
> > seems
> > > > > that
> > > > > > > > > > > > > > > RLMM.onPartitionLeadershipChanges() is only
> > called on
> > > > > the
> > > > > > > > > > replicas
> > > > > > > > > > > > for a
> > > > > > > > > > > > > > > partition, not on the replicas for the
> > > > > > > > > > __remote_log_segment_metadata
> > > > > > > > > > > > > > > partition. It's not clear how the leader of
> > > > > > > > > > > > __remote_log_segment_metadata
> > > > > > > > > > > > > > > obtains the metadata for remote segments for
> > > > deletion.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > RLMM will always receive the callback for the
> > remote
> > > > > log
> > > > > > > > > metadata
> > > > > > > > > > > > > > > topic partitions hosted on the local broker and
> > these
> > > > > will
> > > > > > > be
> > > > > > > > > > > > > > > subscribed. I will make this clear in the KIP.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5100. KIP-516 has been accepted and is being
> > > > > implemented
> > > > > > > now.
> > > > > > > > > > Could
> > > > > > > > > > > > you
> > > > > > > > > > > > > > > update the KIP based on topicID?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > We mentioned KIP-516 and how it helps. We will
> > update
> > > > > this
> > > > > > > KIP
> > > > > > > > > > with
> > > > > > > > > > > > > > > all the changes it brings with KIP-516.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5101. RLMM: It would be useful to clarify how the
> > > > > > > following two
> > > > > > > > > > APIs
> > > > > > > > > > > > are
> > > > > > > > > > > > > > > used. According to the wiki, the former is used
> > for
> > > > > topic
> > > > > > > > > > deletion
> > > > > > > > > > > > and
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > latter is used for retention. It seems that
> > retention
> > > > > > > should
> > > > > > > > > use
> > > > > > > > > > the
> > > > > > > > > > > > > > former
> > > > > > > > > > > > > > > since remote segments without a matching epoch
> > in the
> > > > > > > leader
> > > > > > > > > > > > (potentially
> > > > > > > > > > > > > > > due to unclean leader election) also need to be
> > > > garbage
> > > > > > > > > > collected.
> > > > > > > > > > > > The
> > > > > > > > > > > > > > > latter seems to be used for the new leader to
> > > > > determine the
> > > > > > > > > last
> > > > > > > > > > > > tiered
> > > > > > > > > > > > > > > segment.
> > > > > > > > > > > > > > >     default Iterator<RemoteLogSegmentMetadata>
> > > > > > > > > > > > > > > listRemoteLogSegments(TopicPartition
> > topicPartition)
> > > > > > > > > > > > > > >     Iterator<RemoteLogSegmentMetadata>
> > > > > > > > > > > > > > listRemoteLogSegments(TopicPartition
> > > > > > > > > > > > > > > topicPartition, long leaderEpoch);
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Right,.that is what we are currently doing. We
> > will
> > > > > update
> > > > > > > the
> > > > > > > > > > > > > > > javadocs and wiki with that. Earlier, we did not
> > want
> > > > > to
> > > > > > > remove
> > > > > > > > > > the
> > > > > > > > > > > > > > > segments which are not matched with leader epochs
> > > > from
> > > > > the
> > > > > > > > > ladder
> > > > > > > > > > > > > > > partition as they may be used later by a replica
> > > > which
> > > > > can
> > > > > > > > > > become a
> > > > > > > > > > > > > > > leader (unclean leader election) and refer those
> > > > > segments.
> > > > > > > But
> > > > > > > > > > that
> > > > > > > > > > > > > > > may leak these segments in remote storage until
> > the
> > > > > topic
> > > > > > > > > > lifetime.
> > > > > > > > > > > > We
> > > > > > > > > > > > > > > decided to cleanup the segments with the oldest
> > > > incase
> > > > > of
> > > > > > > size
> > > > > > > > > > based
> > > > > > > > > > > > > > > retention also.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5102. RSM:
> > > > > > > > > > > > > > > 5102.1 For methods like fetchLogSegmentData(), it
> > > > seems
> > > > > > > that
> > > > > > > > > > they can
> > > > > > > > > > > > > > > use RemoteLogSegmentId instead of
> > > > > RemoteLogSegmentMetadata.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > It will be useful to have metadata for RSM to
> > fetch
> > > > log
> > > > > > > > > segment.
> > > > > > > > > > It
> > > > > > > > > > > > > > > may create location/path using id with other
> > metadata
> > > > > too.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5102.2 In fetchLogSegmentData(), should we use
> > long
> > > > > > > instead of
> > > > > > > > > > Long?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Wanted to keep endPosition as optional to read
> > till
> > > > the
> > > > > > > end of
> > > > > > > > > > the
> > > > > > > > > > > > > > > segment and avoid sentinels.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5102.3 Why only some of the methods have default
> > > > > > > implementation
> > > > > > > > > > and
> > > > > > > > > > > > > > others
> > > > > > > > > > > > > > > Don't?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Actually,  RSM will not have any default
> > > > > implementations.
> > > > > > > > > Those 3
> > > > > > > > > > > > > > > methods were made default earlier for tests etc.
> > > > > Updated
> > > > > > > the
> > > > > > > > > > wiki.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5102.4. Could we define
> > > > RemoteLogSegmentMetadataUpdate
> > > > > > > > > > > > > > > and DeletePartitionUpdate?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Sure, they will be added.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5102.5 LogSegmentData: It seems that it's easier
> > to
> > > > > pass
> > > > > > > > > > > > > > > in leaderEpochIndex as a ByteBuffer or byte array
> > > > than
> > > > > a
> > > > > > > file
> > > > > > > > > > since
> > > > > > > > > > > > it
> > > > > > > > > > > > > > will
> > > > > > > > > > > > > > > be generated in memory.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Right, this is in plan.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5102.6 RemoteLogSegmentMetadata: It seems that it
> > > > needs
> > > > > > > both
> > > > > > > > > > > > baseOffset
> > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > startOffset. For example, deleteRecords() could
> > move
> > > > > the
> > > > > > > > > > startOffset
> > > > > > > > > > > > to
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > middle of a segment. If we copy the full segment
> > to
> > > > > remote
> > > > > > > > > > storage,
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > baseOffset and the startOffset will be different.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Good point. startOffset is baseOffset by
> > default, if
> > > > > not
> > > > > > > set
> > > > > > > > > > > > explicitly.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5102.7 Could we define all the public methods for
> > > > > > > > > > > > > > RemoteLogSegmentMetadata
> > > > > > > > > > > > > > > and LogSegmentData?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Sure, updated the wiki.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5102.8 Could we document whether endOffset in
> > > > > > > > > > > > RemoteLogSegmentMetadata is
> > > > > > > > > > > > > > > inclusive/exclusive?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > It is inclusive, will update.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5103. configs:
> > > > > > > > > > > > > > > 5103.1 Could we define the default value of
> > > > > non-required
> > > > > > > > > configs
> > > > > > > > > > > > (e.g the
> > > > > > > > > > > > > > > size of new thread pools)?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Sure, that makes sense.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5103.2 It seems that local.log.retention.ms
> > should
> > > > > > > default to
> > > > > > > > > > > > > > retention.ms,
> > > > > > > > > > > > > > > instead of remote.log.retention.minutes.
> > Similarly,
> > > > it
> > > > > > > seems
> > > > > > > > > > > > > > > that local.log.retention.bytes should default to
> > > > > > > segment.bytes.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Right, we do not have  remote.log.retention as we
> > > > > discussed
> > > > > > > > > > earlier.
> > > > > > > > > > > > > > > Thanks for catching the typo.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5103.3 remote.log.manager.thread.pool.size: The
> > > > > description
> > > > > > > > > says
> > > > > > > > > > > > "used in
> > > > > > > > > > > > > > > scheduling tasks to copy segments, fetch remote
> > log
> > > > > > > indexes and
> > > > > > > > > > > > clean up
> > > > > > > > > > > > > > > remote log segments". However, there is a
> > separate
> > > > > > > > > > > > > > > config remote.log.reader.threads for fetching
> > remote
> > > > > data.
> > > > > > > It's
> > > > > > > > > > > > weird to
> > > > > > > > > > > > > > > fetch remote index and log in different thread
> > pools
> > > > > since
> > > > > > > both
> > > > > > > > > > are
> > > > > > > > > > > > used
> > > > > > > > > > > > > > > for serving fetch requests.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Right, remote.log.manager.thread.pool is mainly
> > used
> > > > > for
> > > > > > > > > > copy/cleanup
> > > > > > > > > > > > > > > activities. Fetch path always goes through
> > > > > > > > > > remote.log.reader.threads.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5103.4 remote.log.manager.task.interval.ms: Is
> > that
> > > > > the
> > > > > > > amount
> > > > > > > > > > of
> > > > > > > > > > > > time
> > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > back off when there is no work to do? If so,
> > perhaps
> > > > it
> > > > > > > can be
> > > > > > > > > > > > renamed as
> > > > > > > > > > > > > > > backoff.ms.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > This is the delay interval for each iteration.
> > It may
> > > > > be
> > > > > > > > > renamed
> > > > > > > > > > to
> > > > > > > > > > > > > > > remote.log.manager.task.delay.ms
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5103.5 Are rlm_process_interval_ms and
> > > > > > > rlm_retry_interval_ms
> > > > > > > > > > > > configs? If
> > > > > > > > > > > > > > > so, they need to be listed in this section.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > remote.log.manager.task.interval.ms is the
> > process
> > > > > > > internal,
> > > > > > > > > > retry
> > > > > > > > > > > > > > > interval is missing in the configs, which will be
> > > > > updated
> > > > > > > in
> > > > > > > > > the
> > > > > > > > > > KIP.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5104. "RLM maintains a bounded cache(possibly
> > LRU) of
> > > > > the
> > > > > > > index
> > > > > > > > > > > > files of
> > > > > > > > > > > > > > > remote log segments to avoid multiple index
> > fetches
> > > > > from
> > > > > > > the
> > > > > > > > > > remote
> > > > > > > > > > > > > > > storage." Is the RLM in memory or on disk? If on
> > > > disk,
> > > > > > > where is
> > > > > > > > > > it
> > > > > > > > > > > > > > stored?
> > > > > > > > > > > > > > > Do we need a configuration to bound the size?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > It is stored on disk. They are stored in a
> > directory
> > > > > > > > > > > > > > > `remote-log-index-cache` under log dir. We plan
> > to
> > > > > have a
> > > > > > > > > config
> > > > > > > > > > for
> > > > > > > > > > > > > > > that instead of default. We will have a
> > configuration
> > > > > for
> > > > > > > that.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5105. The KIP uses local-log-start-offset and
> > > > Earliest
> > > > > > > Local
> > > > > > > > > > Offset
> > > > > > > > > > > > in
> > > > > > > > > > > > > > > different places. It would be useful to
> > standardize
> > > > the
> > > > > > > > > > terminology.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Sure.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5106. The section on "In BuildingRemoteLogAux
> > state".
> > > > > It
> > > > > > > listed
> > > > > > > > > > two
> > > > > > > > > > > > > > options
> > > > > > > > > > > > > > > without saying which option is chosen.
> > > > > > > > > > > > > > > We already mentioned in the KIP that we chose
> > > > option-2.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5107. Follower to leader transition: It has step
> > 2,
> > > > > but not
> > > > > > > > > step
> > > > > > > > > > 1.
> > > > > > > > > > > > > > > Step-1 is there but it is not explicitly
> > highlighted.
> > > > > It is
> > > > > > > > > > previous
> > > > > > > > > > > > > > > table to step-2.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5108. If a consumer fetches from the remote data
> > and
> > > > > the
> > > > > > > remote
> > > > > > > > > > > > storage
> > > > > > > > > > > > > > is
> > > > > > > > > > > > > > > not available, what error code is used in the
> > fetch
> > > > > > > response?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Good point. We have not yet defined the error for
> > > > this
> > > > > > > case. We
> > > > > > > > > > need
> > > > > > > > > > > > > > > to define an error message and send the same in
> > fetch
> > > > > > > response.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5109. "ListOffsets: For timestamps >= 0, it
> > returns
> > > > the
> > > > > > > first
> > > > > > > > > > message
> > > > > > > > > > > > > > > offset whose timestamp is >= to the given
> > timestamp
> > > > in
> > > > > the
> > > > > > > > > > request.
> > > > > > > > > > > > That
> > > > > > > > > > > > > > > means it checks in remote log time indexes first,
> > > > after
> > > > > > > which
> > > > > > > > > > local
> > > > > > > > > > > > log
> > > > > > > > > > > > > > > time indexes are checked." Could you document
> > which
> > > > > method
> > > > > > > in
> > > > > > > > > > RLMM is
> > > > > > > > > > > > > > used
> > > > > > > > > > > > > > > for this?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Okay.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5110. Stopreplica: "it sets all the remote log
> > > > segment
> > > > > > > metadata
> > > > > > > > > > of
> > > > > > > > > > > > that
> > > > > > > > > > > > > > > partition with a delete marker and publishes
> > them to
> > > > > RLMM."
> > > > > > > > > This
> > > > > > > > > > > > seems
> > > > > > > > > > > > > > > outdated given the new topic deletion logic.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Will update with KIP-516 related points.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5111. "RLM follower fetches the earliest offset
> > for
> > > > the
> > > > > > > > > earliest
> > > > > > > > > > > > leader
> > > > > > > > > > > > > > > epoch by calling
> > > > RLMM.earliestLogOffset(TopicPartition
> > > > > > > > > > > > topicPartition,
> > > > > > > > > > > > > > int
> > > > > > > > > > > > > > > leaderEpoch) and updates that as the log start
> > > > > offset." Do
> > > > > > > we
> > > > > > > > > > need
> > > > > > > > > > > > that
> > > > > > > > > > > > > > > since replication propagates logStartOffset
> > already?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Good point. Right, existing replication protocol
> > > > takes
> > > > > > > care of
> > > > > > > > > > > > > > > updating the followers’s log start offset
> > received
> > > > > from the
> > > > > > > > > > leader.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5112. Is the default maxWaitMs of 500ms enough
> > for
> > > > > fetching
> > > > > > > > > from
> > > > > > > > > > > > remote
> > > > > > > > > > > > > > > storage?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Remote reads may fail within the current default
> > wait
> > > > > > > time, but
> > > > > > > > > > > > > > > subsequent fetches would be able to serve as that
> > > > data
> > > > > is
> > > > > > > > > stored
> > > > > > > > > > in
> > > > > > > > > > > > > > > the local cache. This cache is currently
> > implemented
> > > > in
> > > > > > > RSMs.
> > > > > > > > > > But we
> > > > > > > > > > > > > > > plan to pull this into the remote log messaging
> > layer
> > > > > in
> > > > > > > > > future.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5113. "Committed offsets can be stored in a local
> > > > file
> > > > > to
> > > > > > > avoid
> > > > > > > > > > > > reading
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > messages again when a broker is restarted."
> > Could you
> > > > > > > describe
> > > > > > > > > > the
> > > > > > > > > > > > format
> > > > > > > > > > > > > > > and the location of the file? Also, could the
> > same
> > > > > message
> > > > > > > be
> > > > > > > > > > > > processed
> > > > > > > > > > > > > > by
> > > > > > > > > > > > > > > RLMM again after broker restart? If so, how do we
> > > > > handle
> > > > > > > that?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Sure, we will update in the KIP.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5114. Message format
> > > > > > > > > > > > > > > 5114.1 There are two records named
> > > > > > > > > RemoteLogSegmentMetadataRecord
> > > > > > > > > > > > with
> > > > > > > > > > > > > > > apiKey 0 and 1.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Nice catch, that was a typo. Fixed in the wiki.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5114.2 RemoteLogSegmentMetadataRecord: Could we
> > > > > document
> > > > > > > > > whether
> > > > > > > > > > > > > > endOffset
> > > > > > > > > > > > > > > is inclusive/exclusive?
> > > > > > > > > > > > > > > It is inclusive, will update.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5114.3 RemoteLogSegmentMetadataRecord: Could you
> > > > > explain
> > > > > > > > > > LeaderEpoch
> > > > > > > > > > > > a
> > > > > > > > > > > > > > bit
> > > > > > > > > > > > > > > more? Is that the epoch of the leader when it
> > copies
> > > > > the
> > > > > > > > > segment
> > > > > > > > > > to
> > > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > storage? Also, how will this field be used?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Right, this is the leader epoch of the broker
> > which
> > > > > copied
> > > > > > > this
> > > > > > > > > > > > > > > segment. This is helpful in reason about which
> > broker
> > > > > > > copied
> > > > > > > > > the
> > > > > > > > > > > > > > > segment to remote storage.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5114.4 EventTimestamp: Could you explain this a
> > bit
> > > > > more?
> > > > > > > Each
> > > > > > > > > > > > record in
> > > > > > > > > > > > > > > Kafka already has a timestamp field. Could we
> > just
> > > > use
> > > > > > > that?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > This is the  timestamp at which  the respective
> > event
> > > > > > > occurred.
> > > > > > > > > > Added
> > > > > > > > > > > > > > > this  to RemoteLogSegmentMetadata as RLMM can
> > be  any
> > > > > other
> > > > > > > > > > > > > > > implementation. We thought about that but it
> > looked
> > > > > > > cleaner to
> > > > > > > > > > use at
> > > > > > > > > > > > > > > the message structure level instead of getting
> > that
> > > > > from
> > > > > > > the
> > > > > > > > > > consumer
> > > > > > > > > > > > > > > record and using that to build the respective
> > event.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5114.5 SegmentSizeInBytes: Could this just be
> > int32?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Right, it looks like config allows only int
> > value >=
> > > > > 14.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5115. RemoteLogCleaner(RLC): This could be
> > confused
> > > > > with
> > > > > > > the
> > > > > > > > > log
> > > > > > > > > > > > cleaner
> > > > > > > > > > > > > > > for compaction. Perhaps it can be renamed to sth
> > like
> > > > > > > > > > > > > > > RemotePartitionRemover.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > I am fine with RemotePartitionRemover or
> > > > > > > > > > RemoteLogDeletionManager(we
> > > > > > > > > > > > > > > have other manager classes like RLM, RLMM).
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5116. "RLC receives the delete_partition_marked
> > and
> > > > > > > processes
> > > > > > > > > it
> > > > > > > > > > if
> > > > > > > > > > > > it is
> > > > > > > > > > > > > > > not yet processed earlier." How does it know
> > whether
> > > > > > > > > > > > > > > delete_partition_marked has been processed
> > earlier?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > This is to handle duplicate
> > delete_partition_marked
> > > > > > > events. RLC
> > > > > > > > > > > > > > > internally maintains a state for the
> > delete_partition
> > > > > > > events
> > > > > > > > > and
> > > > > > > > > > if
> > > > > > > > > > > > it
> > > > > > > > > > > > > > > already has an existing event then it ignores if
> > it
> > > > is
> > > > > > > already
> > > > > > > > > > being
> > > > > > > > > > > > > > > processed.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5117. Should we add a new MessageFormatter to
> > read
> > > > the
> > > > > tier
> > > > > > > > > > metadata
> > > > > > > > > > > > > > topic?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Right, this is in plan but did not mention it in
> > the
> > > > > KIP.
> > > > > > > This
> > > > > > > > > > will
> > > > > > > > > > > > be
> > > > > > > > > > > > > > > useful for debugging purposes too.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5118. "Maximum remote log reader thread pool task
> > > > queue
> > > > > > > size.
> > > > > > > > > If
> > > > > > > > > > the
> > > > > > > > > > > > task
> > > > > > > > > > > > > > > queue is full, broker will stop reading remote
> > log
> > > > > > > segments."
> > > > > > > > > > What
> > > > > > > > > > > > do we
> > > > > > > > > > > > > > > return to the fetch request in this case?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > We return an error response for that partition.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5119. It would be useful to list all things not
> > > > > supported
> > > > > > > in
> > > > > > > > > the
> > > > > > > > > > > > first
> > > > > > > > > > > > > > > version in a Future work or Limitations section.
> > For
> > > > > > > example,
> > > > > > > > > > > > compacted
> > > > > > > > > > > > > > > topic, JBOD, changing remote.log.storage.enable
> > from
> > > > > true
> > > > > > > to
> > > > > > > > > > false,
> > > > > > > > > > > > etc.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > We already have a non-goals section which is
> > filled
> > > > > with
> > > > > > > some
> > > > > > > > > of
> > > > > > > > > > > > these
> > > > > > > > > > > > > > > details. Do we need another limitations section?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > Satish.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > On Wed, Nov 4, 2020 at 11:27 PM Jun Rao <
> > > > > jun@confluent.io>
> > > > > > > > > > wrote:
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Hi, Satish,
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Thanks for the updated KIP. A few more comments
> > > > > below.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 605.2 "Build the local leader epoch cache by
> > > > cutting
> > > > > the
> > > > > > > > > leader
> > > > > > > > > > > > epoch
> > > > > > > > > > > > > > > > sequence received from remote storage to [LSO,
> > > > > ELO]." I
> > > > > > > > > > mentioned
> > > > > > > > > > > > an
> > > > > > > > > > > > > > issue
> > > > > > > > > > > > > > > > earlier. Suppose the leader's local start
> > offset is
> > > > > 100.
> > > > > > > The
> > > > > > > > > > > > follower
> > > > > > > > > > > > > > finds
> > > > > > > > > > > > > > > > a remote segment covering offset range [80,
> > 120).
> > > > The
> > > > > > > > > > producerState
> > > > > > > > > > > > > > with
> > > > > > > > > > > > > > > > this remote segment is up to offset 120. To
> > trim
> > > > the
> > > > > > > > > > producerState
> > > > > > > > > > > > to
> > > > > > > > > > > > > > > > offset 100 requires more work since one needs
> > to
> > > > > > > download the
> > > > > > > > > > > > previous
> > > > > > > > > > > > > > > > producerState up to offset 80 and then replay
> > the
> > > > > > > messages
> > > > > > > > > > from 80
> > > > > > > > > > > > to
> > > > > > > > > > > > > > 100.
> > > > > > > > > > > > > > > > It seems that it's simpler in this case for the
> > > > > follower
> > > > > > > just
> > > > > > > > > > to
> > > > > > > > > > > > take
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > remote segment as it is and start fetching from
> > > > > offset
> > > > > > > 120.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 5016. Just to echo what Kowshik was saying. It
> > > > seems
> > > > > that
> > > > > > > > > > > > > > > > RLMM.onPartitionLeadershipChanges() is only
> > called
> > > > > on the
> > > > > > > > > > replicas
> > > > > > > > > > > > for
> > > > > > > > > > > > > > a
> > > > > > > > > > > > > > > > partition, not on the replicas for the
> > > > > > > > > > > > __remote_log_segment_metadata
> > > > > > > > > > > > > > > > partition. It's not clear how the leader of
> > > > > > > > > > > > > > __remote_log_segment_metadata
> > > > > > > > > > > > > > > > obtains the metadata for remote segments for
> > > > > deletion.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 5100. KIP-516 has been accepted and is being
> > > > > implemented
> > > > > > > now.
> > > > > > > > > > > > Could you
> > > > > > > > > > > > > > > > update the KIP based on topicID?
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 5101. RLMM: It would be useful to clarify how
> > the
> > > > > > > following
> > > > > > > > > two
> > > > > > > > > > > > APIs
> > > > > > > > > > > > > > are
> > > > > > > > > > > > > > > > used. According to the wiki, the former is
> > used for
> > > > > topic
> > > > > > > > > > deletion
> > > > > > > > > > > > and
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > latter is used for retention. It seems that
> > > > retention
> > > > > > > should
> > > > > > > > > > use
> > > > > > > > > > > > the
> > > > > > > > > > > > > > former
> > > > > > > > > > > > > > > > since remote segments without a matching epoch
> > in
> > > > the
> > > > > > > leader
> > > > > > > > > > > > > > (potentially
> > > > > > > > > > > > > > > > due to unclean leader election) also need to be
> > > > > garbage
> > > > > > > > > > collected.
> > > > > > > > > > > > The
> > > > > > > > > > > > > > > > latter seems to be used for the new leader to
> > > > > determine
> > > > > > > the
> > > > > > > > > > last
> > > > > > > > > > > > tiered
> > > > > > > > > > > > > > > > segment.
> > > > > > > > > > > > > > > >     default Iterator<RemoteLogSegmentMetadata>
> > > > > > > > > > > > > > > > listRemoteLogSegments(TopicPartition
> > > > topicPartition)
> > > > > > > > > > > > > > > >     Iterator<RemoteLogSegmentMetadata>
> > > > > > > > > > > > > > listRemoteLogSegments(TopicPartition
> > > > > > > > > > > > > > > > topicPartition, long leaderEpoch);
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 5102. RSM:
> > > > > > > > > > > > > > > > 5102.1 For methods like fetchLogSegmentData(),
> > it
> > > > > seems
> > > > > > > that
> > > > > > > > > > they
> > > > > > > > > > > > can
> > > > > > > > > > > > > > > > use RemoteLogSegmentId instead of
> > > > > > > RemoteLogSegmentMetadata.
> > > > > > > > > > > > > > > > 5102.2 In fetchLogSegmentData(), should we use
> > long
> > > > > > > instead
> > > > > > > > > of
> > > > > > > > > > > > Long?
> > > > > > > > > > > > > > > > 5102.3 Why only some of the methods have
> > default
> > > > > > > > > > implementation and
> > > > > > > > > > > > > > others
> > > > > > > > > > > > > > > > don't?
> > > > > > > > > > > > > > > > 5102.4. Could we define
> > > > > RemoteLogSegmentMetadataUpdate
> > > > > > > > > > > > > > > > and DeletePartitionUpdate?
> > > > > > > > > > > > > > > > 5102.5 LogSegmentData: It seems that it's
> > easier to
> > > > > pass
> > > > > > > > > > > > > > > > in leaderEpochIndex as a ByteBuffer or byte
> > array
> > > > > than a
> > > > > > > file
> > > > > > > > > > > > since it
> > > > > > > > > > > > > > will
> > > > > > > > > > > > > > > > be generated in memory.
> > > > > > > > > > > > > > > > 5102.6 RemoteLogSegmentMetadata: It seems that
> > it
> > > > > needs
> > > > > > > both
> > > > > > > > > > > > > > baseOffset and
> > > > > > > > > > > > > > > > startOffset. For example, deleteRecords() could
> > > > move
> > > > > the
> > > > > > > > > > > > startOffset
> > > > > > > > > > > > > > to the
> > > > > > > > > > > > > > > > middle of a segment. If we copy the full
> > segment to
> > > > > > > remote
> > > > > > > > > > > > storage, the
> > > > > > > > > > > > > > > > baseOffset and the startOffset will be
> > different.
> > > > > > > > > > > > > > > > 5102.7 Could we define all the public methods
> > for
> > > > > > > > > > > > > > RemoteLogSegmentMetadata
> > > > > > > > > > > > > > > > and LogSegmentData?
> > > > > > > > > > > > > > > > 5102.8 Could we document whether endOffset in
> > > > > > > > > > > > RemoteLogSegmentMetadata
> > > > > > > > > > > > > > is
> > > > > > > > > > > > > > > > inclusive/exclusive?
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 5103. configs:
> > > > > > > > > > > > > > > > 5103.1 Could we define the default value of
> > > > > non-required
> > > > > > > > > > configs
> > > > > > > > > > > > (e.g
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > size of new thread pools)?
> > > > > > > > > > > > > > > > 5103.2 It seems that local.log.retention.ms
> > should
> > > > > > > default
> > > > > > > > > to
> > > > > > > > > > > > > > retention.ms,
> > > > > > > > > > > > > > > > instead of remote.log.retention.minutes.
> > Similarly,
> > > > > it
> > > > > > > seems
> > > > > > > > > > > > > > > > that local.log.retention.bytes should default
> > to
> > > > > > > > > segment.bytes.
> > > > > > > > > > > > > > > > 5103.3 remote.log.manager.thread.pool.size: The
> > > > > > > description
> > > > > > > > > > says
> > > > > > > > > > > > "used
> > > > > > > > > > > > > > in
> > > > > > > > > > > > > > > > scheduling tasks to copy segments, fetch
> > remote log
> > > > > > > indexes
> > > > > > > > > and
> > > > > > > > > > > > clean
> > > > > > > > > > > > > > up
> > > > > > > > > > > > > > > > remote log segments". However, there is a
> > separate
> > > > > > > > > > > > > > > > config remote.log.reader.threads for fetching
> > > > remote
> > > > > > > data.
> > > > > > > > > It's
> > > > > > > > > > > > weird
> > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > fetch remote index and log in different thread
> > > > pools
> > > > > > > since
> > > > > > > > > > both are
> > > > > > > > > > > > > > used
> > > > > > > > > > > > > > > > for serving fetch requests.
> > > > > > > > > > > > > > > > 5103.4 remote.log.manager.task.interval.ms: Is
> > > > that
> > > > > the
> > > > > > > > > > amount of
> > > > > > > > > > > > > > time to
> > > > > > > > > > > > > > > > back off when there is no work to do? If so,
> > > > perhaps
> > > > > it
> > > > > > > can
> > > > > > > > > be
> > > > > > > > > > > > renamed
> > > > > > > > > > > > > > as
> > > > > > > > > > > > > > > > backoff.ms.
> > > > > > > > > > > > > > > > 5103.5 Are rlm_process_interval_ms and
> > > > > > > rlm_retry_interval_ms
> > > > > > > > > > > > configs?
> > > > > > > > > > > > > > If
> > > > > > > > > > > > > > > > so, they need to be listed in this section.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 5104. "RLM maintains a bounded cache(possibly
> > LRU)
> > > > > of the
> > > > > > > > > index
> > > > > > > > > > > > files
> > > > > > > > > > > > > > of
> > > > > > > > > > > > > > > > remote log segments to avoid multiple index
> > fetches
> > > > > from
> > > > > > > the
> > > > > > > > > > remote
> > > > > > > > > > > > > > > > storage." Is the RLM in memory or on disk? If
> > on
> > > > > disk,
> > > > > > > where
> > > > > > > > > > is it
> > > > > > > > > > > > > > stored?
> > > > > > > > > > > > > > > > Do we need a configuration to bound the size?
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 5105. The KIP uses local-log-start-offset and
> > > > > Earliest
> > > > > > > Local
> > > > > > > > > > > > Offset in
> > > > > > > > > > > > > > > > different places. It would be useful to
> > standardize
> > > > > the
> > > > > > > > > > > > terminology.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 5106. The section on "In BuildingRemoteLogAux
> > > > > state". It
> > > > > > > > > > listed two
> > > > > > > > > > > > > > options
> > > > > > > > > > > > > > > > without saying which option is chosen.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 5107. Follower to leader transition: It has
> > step 2,
> > > > > but
> > > > > > > not
> > > > > > > > > > step 1.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 5108. If a consumer fetches from the remote
> > data
> > > > and
> > > > > the
> > > > > > > > > remote
> > > > > > > > > > > > > > storage is
> > > > > > > > > > > > > > > > not available, what error code is used in the
> > fetch
> > > > > > > response?
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 5109. "ListOffsets: For timestamps >= 0, it
> > returns
> > > > > the
> > > > > > > first
> > > > > > > > > > > > message
> > > > > > > > > > > > > > > > offset whose timestamp is >= to the given
> > timestamp
> > > > > in
> > > > > > > the
> > > > > > > > > > request.
> > > > > > > > > > > > > > That
> > > > > > > > > > > > > > > > means it checks in remote log time indexes
> > first,
> > > > > after
> > > > > > > which
> > > > > > > > > > > > local log
> > > > > > > > > > > > > > > > time indexes are checked." Could you document
> > which
> > > > > > > method in
> > > > > > > > > > RLMM
> > > > > > > > > > > > is
> > > > > > > > > > > > > > used
> > > > > > > > > > > > > > > > for this?
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 5110. Stopreplica: "it sets all the remote log
> > > > > segment
> > > > > > > > > > metadata of
> > > > > > > > > > > > that
> > > > > > > > > > > > > > > > partition with a delete marker and publishes
> > them
> > > > to
> > > > > > > RLMM."
> > > > > > > > > > This
> > > > > > > > > > > > seems
> > > > > > > > > > > > > > > > outdated given the new topic deletion logic.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 5111. "RLM follower fetches the earliest
> > offset for
> > > > > the
> > > > > > > > > > earliest
> > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > epoch by calling
> > > > > RLMM.earliestLogOffset(TopicPartition
> > > > > > > > > > > > topicPartition,
> > > > > > > > > > > > > > int
> > > > > > > > > > > > > > > > leaderEpoch) and updates that as the log start
> > > > > offset."
> > > > > > > Do we
> > > > > > > > > > need
> > > > > > > > > > > > that
> > > > > > > > > > > > > > > > since replication propagates logStartOffset
> > > > already?
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 5112. Is the default maxWaitMs of 500ms enough
> > for
> > > > > > > fetching
> > > > > > > > > > from
> > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > storage?
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 5113. "Committed offsets can be stored in a
> > local
> > > > > file to
> > > > > > > > > avoid
> > > > > > > > > > > > > > reading the
> > > > > > > > > > > > > > > > messages again when a broker is restarted."
> > Could
> > > > you
> > > > > > > > > describe
> > > > > > > > > > the
> > > > > > > > > > > > > > format
> > > > > > > > > > > > > > > > and the location of the file? Also, could the
> > same
> > > > > > > message be
> > > > > > > > > > > > > > processed by
> > > > > > > > > > > > > > > > RLMM again after broker restart? If so, how do
> > we
> > > > > handle
> > > > > > > > > that?
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 5114. Message format
> > > > > > > > > > > > > > > > 5114.1 There are two records named
> > > > > > > > > > RemoteLogSegmentMetadataRecord
> > > > > > > > > > > > with
> > > > > > > > > > > > > > > > apiKey 0 and 1.
> > > > > > > > > > > > > > > > 5114.2 RemoteLogSegmentMetadataRecord: Could we
> > > > > document
> > > > > > > > > > whether
> > > > > > > > > > > > > > endOffset
> > > > > > > > > > > > > > > > is inclusive/exclusive?
> > > > > > > > > > > > > > > > 5114.3 RemoteLogSegmentMetadataRecord: Could
> > you
> > > > > explain
> > > > > > > > > > > > LeaderEpoch a
> > > > > > > > > > > > > > bit
> > > > > > > > > > > > > > > > more? Is that the epoch of the leader when it
> > > > copies
> > > > > the
> > > > > > > > > > segment to
> > > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > storage? Also, how will this field be used?
> > > > > > > > > > > > > > > > 5114.4 EventTimestamp: Could you explain this
> > a bit
> > > > > more?
> > > > > > > > > Each
> > > > > > > > > > > > record
> > > > > > > > > > > > > > in
> > > > > > > > > > > > > > > > Kafka already has a timestamp field. Could we
> > just
> > > > > use
> > > > > > > that?
> > > > > > > > > > > > > > > > 5114.5 SegmentSizeInBytes: Could this just be
> > > > int32?
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 5115. RemoteLogCleaner(RLC): This could be
> > confused
> > > > > with
> > > > > > > the
> > > > > > > > > > log
> > > > > > > > > > > > > > cleaner
> > > > > > > > > > > > > > > > for compaction. Perhaps it can be renamed to
> > sth
> > > > like
> > > > > > > > > > > > > > > > RemotePartitionRemover.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 5116. "RLC receives the
> > delete_partition_marked and
> > > > > > > processes
> > > > > > > > > > it
> > > > > > > > > > > > if it
> > > > > > > > > > > > > > is
> > > > > > > > > > > > > > > > not yet processed earlier." How does it know
> > > > whether
> > > > > > > > > > > > > > > > delete_partition_marked has been processed
> > earlier?
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 5117. Should we add a new MessageFormatter to
> > read
> > > > > the
> > > > > > > tier
> > > > > > > > > > > > metadata
> > > > > > > > > > > > > > topic?
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 5118. "Maximum remote log reader thread pool
> > task
> > > > > queue
> > > > > > > size.
> > > > > > > > > > If
> > > > > > > > > > > > the
> > > > > > > > > > > > > > task
> > > > > > > > > > > > > > > > queue is full, broker will stop reading remote
> > log
> > > > > > > segments."
> > > > > > > > > > What
> > > > > > > > > > > > do
> > > > > > > > > > > > > > we
> > > > > > > > > > > > > > > > return to the fetch request in this case?
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 5119. It would be useful to list all things not
> > > > > > > supported in
> > > > > > > > > > the
> > > > > > > > > > > > first
> > > > > > > > > > > > > > > > version in a Future work or Limitations
> > section.
> > > > For
> > > > > > > example,
> > > > > > > > > > > > compacted
> > > > > > > > > > > > > > > > topic, JBOD, changing remote.log.storage.enable
> > > > from
> > > > > > > true to
> > > > > > > > > > false,
> > > > > > > > > > > > > > etc.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Jun
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > On Tue, Oct 27, 2020 at 5:57 PM Kowshik
> > Prakasam <
> > > > > > > > > > > > > > kprakasam@confluent.io>
> > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Hi Satish,
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Thanks for the updates to the KIP. Here are
> > my
> > > > > first
> > > > > > > batch
> > > > > > > > > of
> > > > > > > > > > > > > > > > > comments/suggestions on the latest version
> > of the
> > > > > KIP.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 5012. In the RemoteStorageManager interface,
> > > > there
> > > > > is
> > > > > > > an
> > > > > > > > > API
> > > > > > > > > > > > defined
> > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > > each file type. For example,
> > fetchOffsetIndex,
> > > > > > > > > > > > fetchTimestampIndex
> > > > > > > > > > > > > > etc. To
> > > > > > > > > > > > > > > > > avoid the duplication, I'd suggest we can
> > instead
> > > > > have
> > > > > > > a
> > > > > > > > > > FileType
> > > > > > > > > > > > > > enum and
> > > > > > > > > > > > > > > > > a common get API based on the FileType.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 5013. There are some references to the
> > Google doc
> > > > > in
> > > > > > > the
> > > > > > > > > > KIP. I
> > > > > > > > > > > > > > wasn't sure
> > > > > > > > > > > > > > > > > if the Google doc is expected to be in sync
> > with
> > > > > the
> > > > > > > > > > contents of
> > > > > > > > > > > > the
> > > > > > > > > > > > > > wiki.
> > > > > > > > > > > > > > > > > Going forward, it seems easier if just the
> > KIP is
> > > > > > > > > maintained
> > > > > > > > > > as
> > > > > > > > > > > > the
> > > > > > > > > > > > > > source
> > > > > > > > > > > > > > > > > of truth. In this regard, could you please
> > move
> > > > > all the
> > > > > > > > > > > > references
> > > > > > > > > > > > > > to the
> > > > > > > > > > > > > > > > > Google doc, maybe to a separate References
> > > > section
> > > > > at
> > > > > > > the
> > > > > > > > > > bottom
> > > > > > > > > > > > of
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > KIP?
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 5014. There are some TODO sections in the
> > KIP.
> > > > > Would
> > > > > > > these
> > > > > > > > > be
> > > > > > > > > > > > filled
> > > > > > > > > > > > > > up in
> > > > > > > > > > > > > > > > > future iterations?
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 5015. Under "Topic deletion lifecycle", I'm
> > > > trying
> > > > > to
> > > > > > > > > > understand
> > > > > > > > > > > > why
> > > > > > > > > > > > > > do we
> > > > > > > > > > > > > > > > > need delete_partition_marked as well as the
> > > > > > > > > > > > delete_partition_started
> > > > > > > > > > > > > > > > > messages. I couldn't spot a drawback if
> > supposing
> > > > > we
> > > > > > > > > > simplified
> > > > > > > > > > > > the
> > > > > > > > > > > > > > design
> > > > > > > > > > > > > > > > > such that the controller would only write
> > > > > > > > > > > > delete_partition_started
> > > > > > > > > > > > > > message,
> > > > > > > > > > > > > > > > > and RemoteLogCleaner (RLC) instance picks it
> > up
> > > > for
> > > > > > > > > > processing.
> > > > > > > > > > > > What
> > > > > > > > > > > > > > am I
> > > > > > > > > > > > > > > > > missing?
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 5016. Under "Topic deletion lifecycle", step
> > (4)
> > > > is
> > > > > > > > > > mentioned as
> > > > > > > > > > > > > > "RLC gets
> > > > > > > > > > > > > > > > > all the remote log segments for the
> > partition and
> > > > > each
> > > > > > > of
> > > > > > > > > > these
> > > > > > > > > > > > > > remote log
> > > > > > > > > > > > > > > > > segments is deleted with the next steps.".
> > Since
> > > > > the
> > > > > > > RLC
> > > > > > > > > > instance
> > > > > > > > > > > > > > runs on
> > > > > > > > > > > > > > > > > each tier topic partition leader, how does
> > the
> > > > RLC
> > > > > > > then get
> > > > > > > > > > the
> > > > > > > > > > > > list
> > > > > > > > > > > > > > of
> > > > > > > > > > > > > > > > > remote log segments to be deleted? It will be
> > > > > useful
> > > > > > > to add
> > > > > > > > > > that
> > > > > > > > > > > > > > detail to
> > > > > > > > > > > > > > > > > the KIP.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 5017. Under "Public Interfaces -> Configs",
> > there
> > > > > is a
> > > > > > > line
> > > > > > > > > > > > > > mentioning "We
> > > > > > > > > > > > > > > > > will support flipping
> > remote.log.storage.enable
> > > > in
> > > > > next
> > > > > > > > > > > > versions."
> > > > > > > > > > > > > > It will
> > > > > > > > > > > > > > > > > be useful to mention this in the "Future
> > Work"
> > > > > section
> > > > > > > of
> > > > > > > > > > the KIP
> > > > > > > > > > > > > > too.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 5018. The KIP introduces a number of
> > > > configuration
> > > > > > > > > > parameters. It
> > > > > > > > > > > > > > will be
> > > > > > > > > > > > > > > > > useful to mention in the KIP if the user
> > should
> > > > > assume
> > > > > > > > > these
> > > > > > > > > > as
> > > > > > > > > > > > > > static
> > > > > > > > > > > > > > > > > configuration in the server.properties file,
> > or
> > > > > dynamic
> > > > > > > > > > > > > > configuration which
> > > > > > > > > > > > > > > > > can be modified without restarting the
> > broker.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 5019.  Maybe this is planned as a future
> > update
> > > > to
> > > > > the
> > > > > > > KIP,
> > > > > > > > > > but I
> > > > > > > > > > > > > > thought
> > > > > > > > > > > > > > > > > I'd mention it here. Could you please add
> > details
> > > > > to
> > > > > > > the
> > > > > > > > > KIP
> > > > > > > > > > on
> > > > > > > > > > > > why
> > > > > > > > > > > > > > RocksDB
> > > > > > > > > > > > > > > > > was chosen as the default cache
> > implementation of
> > > > > > > RLMM, and
> > > > > > > > > > how
> > > > > > > > > > > > it
> > > > > > > > > > > > > > is going
> > > > > > > > > > > > > > > > > to be used? Were alternatives
> > > > compared/considered?
> > > > > For
> > > > > > > > > > example,
> > > > > > > > > > > > it
> > > > > > > > > > > > > > would be
> > > > > > > > > > > > > > > > > useful to explain/evaluate the following: 1)
> > > > > > > debuggability
> > > > > > > > > > of the
> > > > > > > > > > > > > > RocksDB
> > > > > > > > > > > > > > > > > JNI interface, 2) performance, 3) portability
> > > > > across
> > > > > > > > > > platforms
> > > > > > > > > > > > and 4)
> > > > > > > > > > > > > > > > > interface parity of RocksDB’s JNI api with
> > it's
> > > > > > > underlying
> > > > > > > > > > C/C++
> > > > > > > > > > > > api.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 5020. Following up on (5019), for the RocksDB
> > > > > cache, it
> > > > > > > > > will
> > > > > > > > > > be
> > > > > > > > > > > > > > useful to
> > > > > > > > > > > > > > > > > explain the relationship/mapping between the
> > > > > following
> > > > > > > in
> > > > > > > > > the
> > > > > > > > > > > > KIP:
> > > > > > > > > > > > > > 1) # of
> > > > > > > > > > > > > > > > > tiered partitions, 2) # of partitions of
> > metadata
> > > > > topic
> > > > > > > > > > > > > > > > > __remote_log_metadata and 3) # of RocksDB
> > > > > instances.
> > > > > > > i.e.
> > > > > > > > > is
> > > > > > > > > > the
> > > > > > > > > > > > > > plan to
> > > > > > > > > > > > > > > > > have a RocksDB instance per tiered
> > partition, or
> > > > > per
> > > > > > > > > metadata
> > > > > > > > > > > > topic
> > > > > > > > > > > > > > > > > partition, or just 1 for per broker?
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 5021. I was looking at the implementation
> > > > > prototype (PR
> > > > > > > > > link:
> > > > > > > > > > > > > > > > > https://github.com/apache/kafka/pull/7561).
> > It
> > > > > seems
> > > > > > > that
> > > > > > > > > a
> > > > > > > > > > > > boolean
> > > > > > > > > > > > > > > > > attribute is being introduced into the Log
> > layer
> > > > to
> > > > > > > check
> > > > > > > > > if
> > > > > > > > > > > > remote
> > > > > > > > > > > > > > log
> > > > > > > > > > > > > > > > > capability is enabled. While the boolean
> > > > footprint
> > > > > is
> > > > > > > small
> > > > > > > > > > at
> > > > > > > > > > > > the
> > > > > > > > > > > > > > moment,
> > > > > > > > > > > > > > > > > this can easily grow in the future and become
> > > > > harder to
> > > > > > > > > > > > > > > > > test/maintain, considering that the Log
> > layer is
> > > > > > > already
> > > > > > > > > > pretty
> > > > > > > > > > > > > > complex. We
> > > > > > > > > > > > > > > > > should start thinking about how to manage
> > such
> > > > > changes
> > > > > > > to
> > > > > > > > > > the Log
> > > > > > > > > > > > > > layer
> > > > > > > > > > > > > > > > > (for the purpose of improved testability,
> > better
> > > > > > > separation
> > > > > > > > > > of
> > > > > > > > > > > > > > concerns and
> > > > > > > > > > > > > > > > > readability). One proposal I have is to take
> > a
> > > > step
> > > > > > > back
> > > > > > > > > and
> > > > > > > > > > > > define a
> > > > > > > > > > > > > > > > > higher level Log interface. Then, the Broker
> > code
> > > > > can
> > > > > > > be
> > > > > > > > > > changed
> > > > > > > > > > > > to
> > > > > > > > > > > > > > use
> > > > > > > > > > > > > > > > > this interface. It can be changed such that
> > only
> > > > a
> > > > > > > handle
> > > > > > > > > to
> > > > > > > > > > the
> > > > > > > > > > > > > > interface
> > > > > > > > > > > > > > > > > is exposed to other components (such as
> > > > LogCleaner,
> > > > > > > > > > > > ReplicaManager
> > > > > > > > > > > > > > etc.)
> > > > > > > > > > > > > > > > > and not the underlying Log object. This
> > approach
> > > > > keeps
> > > > > > > the
> > > > > > > > > > user
> > > > > > > > > > > > of
> > > > > > > > > > > > > > the Log
> > > > > > > > > > > > > > > > > layer agnostic of the whereabouts of the
> > data.
> > > > > > > Underneath
> > > > > > > > > the
> > > > > > > > > > > > > > interface,
> > > > > > > > > > > > > > > > > the implementing classes can completely
> > separate
> > > > > local
> > > > > > > log
> > > > > > > > > > > > > > capabilities
> > > > > > > > > > > > > > > > > from the remote log. For example, the Log
> > class
> > > > > can be
> > > > > > > > > > > > simplified to
> > > > > > > > > > > > > > only
> > > > > > > > > > > > > > > > > manage logic surrounding local log segments
> > and
> > > > > > > metadata.
> > > > > > > > > > > > > > Additionally, a
> > > > > > > > > > > > > > > > > wrapper class can be provided (implementing
> > the
> > > > > higher
> > > > > > > > > level
> > > > > > > > > > Log
> > > > > > > > > > > > > > interface)
> > > > > > > > > > > > > > > > > which will contain any/all logic surrounding
> > > > tiered
> > > > > > > data.
> > > > > > > > > The
> > > > > > > > > > > > wrapper
> > > > > > > > > > > > > > > > > class will wrap around an instance of the Log
> > > > class
> > > > > > > > > > delegating
> > > > > > > > > > > > the
> > > > > > > > > > > > > > local
> > > > > > > > > > > > > > > > > log logic to it. Finally, a handle to the
> > wrapper
> > > > > > > class can
> > > > > > > > > > be
> > > > > > > > > > > > > > exposed to
> > > > > > > > > > > > > > > > > the other components wherever they need a
> > handle
> > > > > to the
> > > > > > > > > > higher
> > > > > > > > > > > > level
> > > > > > > > > > > > > > Log
> > > > > > > > > > > > > > > > > interface.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Cheers,
> > > > > > > > > > > > > > > > > Kowshik
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > On Mon, Oct 26, 2020 at 9:52 PM Satish
> > Duggana <
> > > > > > > > > > > > > > satish.duggana@gmail.com>
> > > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > Hi,
> > > > > > > > > > > > > > > > > > KIP is updated with 1) topic deletion
> > lifecycle
> > > > > and
> > > > > > > its
> > > > > > > > > > related
> > > > > > > > > > > > > > items
> > > > > > > > > > > > > > > > > > 2) Protocol changes(mainly related to
> > > > > ListOffsets)
> > > > > > > and
> > > > > > > > > > other
> > > > > > > > > > > > minor
> > > > > > > > > > > > > > > > > > changes.
> > > > > > > > > > > > > > > > > > Please go through them and let us know your
> > > > > comments.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > > > Satish.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > On Mon, Sep 28, 2020 at 9:10 PM Satish
> > Duggana
> > > > <
> > > > > > > > > > > > > > satish.duggana@gmail.com
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Hi Dhruvil,
> > > > > > > > > > > > > > > > > > > Thanks for looking into the KIP and
> > sending
> > > > > your
> > > > > > > > > > comments.
> > > > > > > > > > > > Sorry
> > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > > > > the late reply, missed it in the mail
> > thread.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 1. Could you describe how retention would
> > > > work
> > > > > with
> > > > > > > > > this
> > > > > > > > > > KIP
> > > > > > > > > > > > and
> > > > > > > > > > > > > > which
> > > > > > > > > > > > > > > > > > > threads are responsible for driving this
> > > > work?
> > > > > I
> > > > > > > > > believe
> > > > > > > > > > > > there
> > > > > > > > > > > > > > are 3
> > > > > > > > > > > > > > > > > > kinds
> > > > > > > > > > > > > > > > > > > of retention processes we are looking at:
> > > > > > > > > > > > > > > > > > >   (a) Regular retention for data in
> > tiered
> > > > > storage
> > > > > > > as
> > > > > > > > > per
> > > > > > > > > > > > > > configured `
> > > > > > > > > > > > > > > > > > > retention.ms` / `retention.bytes`.
> > > > > > > > > > > > > > > > > > >   (b) Local retention for data in local
> > > > > storage as
> > > > > > > per
> > > > > > > > > > > > > > configured `
> > > > > > > > > > > > > > > > > > > local.log.retention.ms` /
> > > > > > > `local.log.retention.bytes`
> > > > > > > > > > > > > > > > > > >   (c) Possibly regular retention for
> > data in
> > > > > local
> > > > > > > > > > storage,
> > > > > > > > > > > > if
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > tiering
> > > > > > > > > > > > > > > > > > > task is lagging or for data that is
> > below the
> > > > > log
> > > > > > > start
> > > > > > > > > > > > offset.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Local log retention is done by the
> > existing
> > > > log
> > > > > > > cleanup
> > > > > > > > > > > > tasks.
> > > > > > > > > > > > > > These
> > > > > > > > > > > > > > > > > > > are not done for segments that are not
> > yet
> > > > > copied
> > > > > > > to
> > > > > > > > > > remote
> > > > > > > > > > > > > > storage.
> > > > > > > > > > > > > > > > > > > Remote log cleanup is done by the leader
> > > > > > > partition’s
> > > > > > > > > > RLMTask.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 2. When does a segment become eligible
> > to be
> > > > > > > tiered? Is
> > > > > > > > > > it as
> > > > > > > > > > > > > > soon as
> > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > segment is rolled and the end offset is
> > less
> > > > > than
> > > > > > > the
> > > > > > > > > > last
> > > > > > > > > > > > stable
> > > > > > > > > > > > > > > > > offset
> > > > > > > > > > > > > > > > > > as
> > > > > > > > > > > > > > > > > > > mentioned in the KIP? I wonder if we
> > need to
> > > > > > > consider
> > > > > > > > > > other
> > > > > > > > > > > > > > parameters
> > > > > > > > > > > > > > > > > > too,
> > > > > > > > > > > > > > > > > > > like the highwatermark so that we are
> > > > > guaranteed
> > > > > > > that
> > > > > > > > > > what
> > > > > > > > > > > > we are
> > > > > > > > > > > > > > > > > tiering
> > > > > > > > > > > > > > > > > > > has been committed to the log and
> > accepted by
> > > > > the
> > > > > > > ISR.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > AFAIK, last stable offset is always <=
> > > > > > > highwatermark.
> > > > > > > > > > This
> > > > > > > > > > > > will
> > > > > > > > > > > > > > make
> > > > > > > > > > > > > > > > > > > sure we are always tiering the message
> > > > segments
> > > > > > > which
> > > > > > > > > > have
> > > > > > > > > > > > been
> > > > > > > > > > > > > > > > > > > accepted by ISR and transactionally
> > > > completed.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 3. The section on "Follower Fetch
> > Scenarios"
> > > > is
> > > > > > > useful
> > > > > > > > > > but
> > > > > > > > > > > > is a
> > > > > > > > > > > > > > bit
> > > > > > > > > > > > > > > > > > > difficult to parse at the moment. It
> > would be
> > > > > > > useful to
> > > > > > > > > > > > > > summarize the
> > > > > > > > > > > > > > > > > > > changes we need in the ReplicaFetcher.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > It may become difficult for users to
> > > > > read/follow
> > > > > > > if we
> > > > > > > > > > add
> > > > > > > > > > > > code
> > > > > > > > > > > > > > changes
> > > > > > > > > > > > > > > > > > here.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 4. Related to the above, it's a bit
> > unclear
> > > > > how we
> > > > > > > are
> > > > > > > > > > > > planning
> > > > > > > > > > > > > > on
> > > > > > > > > > > > > > > > > > > restoring the producer state for a new
> > > > replica.
> > > > > > > Could
> > > > > > > > > you
> > > > > > > > > > > > expand
> > > > > > > > > > > > > > on
> > > > > > > > > > > > > > > > > that?
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > It is mentioned in the KIP
> > > > > > > BuildingRemoteLogAuxState is
> > > > > > > > > > > > > > introduced to
> > > > > > > > > > > > > > > > > > > build the state like leader epoch
> > sequence
> > > > and
> > > > > > > producer
> > > > > > > > > > > > snapshots
> > > > > > > > > > > > > > > > > > > before it starts fetching the data from
> > the
> > > > > > > leader. We
> > > > > > > > > > will
> > > > > > > > > > > > make
> > > > > > > > > > > > > > it
> > > > > > > > > > > > > > > > > > > clear in the KIP.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 5. Similarly, it would be worth
> > summarizing
> > > > the
> > > > > > > > > behavior
> > > > > > > > > > on
> > > > > > > > > > > > > > unclean
> > > > > > > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > > > > election. There are several scenarios to
> > > > > consider
> > > > > > > here:
> > > > > > > > > > data
> > > > > > > > > > > > > > loss from
> > > > > > > > > > > > > > > > > > > local log, data loss from remote log,
> > data
> > > > loss
> > > > > > > from
> > > > > > > > > > metadata
> > > > > > > > > > > > > > topic,
> > > > > > > > > > > > > > > > > etc.
> > > > > > > > > > > > > > > > > > > It's worth describing these in detail.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > We mentioned the cases about unclean
> > leader
> > > > > > > election in
> > > > > > > > > > the
> > > > > > > > > > > > > > follower
> > > > > > > > > > > > > > > > > > > fetch scenarios.
> > > > > > > > > > > > > > > > > > > If there are errors while fetching data
> > from
> > > > > remote
> > > > > > > > > > store or
> > > > > > > > > > > > > > metadata
> > > > > > > > > > > > > > > > > > > store, it will work the same way as it
> > works
> > > > > with
> > > > > > > local
> > > > > > > > > > log.
> > > > > > > > > > > > It
> > > > > > > > > > > > > > > > > > > returns the error back to the caller.
> > Please
> > > > > let us
> > > > > > > > > know
> > > > > > > > > > if
> > > > > > > > > > > > I am
> > > > > > > > > > > > > > > > > > > missing your point here.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 7. For a READ_COMMITTED FetchRequest,
> > how do
> > > > we
> > > > > > > > > retrieve
> > > > > > > > > > and
> > > > > > > > > > > > > > return the
> > > > > > > > > > > > > > > > > > > aborted transaction metadata?
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > When a fetch for a remote log is
> > accessed, we
> > > > > will
> > > > > > > > > fetch
> > > > > > > > > > > > aborted
> > > > > > > > > > > > > > > > > > > transactions along with the segment if
> > it is
> > > > > not
> > > > > > > found
> > > > > > > > > > in the
> > > > > > > > > > > > > > local
> > > > > > > > > > > > > > > > > > > index cache. This includes the case of
> > > > > transaction
> > > > > > > > > index
> > > > > > > > > > not
> > > > > > > > > > > > > > existing
> > > > > > > > > > > > > > > > > > > in the remote log segment. That means,
> > the
> > > > > cache
> > > > > > > entry
> > > > > > > > > > can be
> > > > > > > > > > > > > > empty or
> > > > > > > > > > > > > > > > > > > have a list of aborted transactions.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 8. The `LogSegmentData` class assumes
> > that we
> > > > > have
> > > > > > > a
> > > > > > > > > log
> > > > > > > > > > > > segment,
> > > > > > > > > > > > > > > > > offset
> > > > > > > > > > > > > > > > > > > index, time index, transaction index,
> > > > producer
> > > > > > > snapshot
> > > > > > > > > > and
> > > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > > epoch
> > > > > > > > > > > > > > > > > > > index. How do we deal with cases where
> > we do
> > > > > not
> > > > > > > have
> > > > > > > > > > one or
> > > > > > > > > > > > > > more of
> > > > > > > > > > > > > > > > > > these?
> > > > > > > > > > > > > > > > > > > For example, we may not have a
> > transaction
> > > > > index or
> > > > > > > > > > producer
> > > > > > > > > > > > > > snapshot
> > > > > > > > > > > > > > > > > > for a
> > > > > > > > > > > > > > > > > > > particular segment. The former is
> > optional,
> > > > > and the
> > > > > > > > > > latter is
> > > > > > > > > > > > > > only kept
> > > > > > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > > > > up to the 3 latest segments.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > This is a good point,  we discussed this
> > in
> > > > the
> > > > > > > last
> > > > > > > > > > meeting.
> > > > > > > > > > > > > > > > > > > Transaction index is optional and we will
> > > > copy
> > > > > them
> > > > > > > > > only
> > > > > > > > > > if
> > > > > > > > > > > > it
> > > > > > > > > > > > > > exists.
> > > > > > > > > > > > > > > > > > > We want to keep all the producer
> > snapshots at
> > > > > each
> > > > > > > log
> > > > > > > > > > > > segment
> > > > > > > > > > > > > > rolling
> > > > > > > > > > > > > > > > > > > and they can be removed if the log
> > copying is
> > > > > > > > > successful
> > > > > > > > > > and
> > > > > > > > > > > > it
> > > > > > > > > > > > > > still
> > > > > > > > > > > > > > > > > > > maintains the existing latest 3
> > segments, We
> > > > > only
> > > > > > > > > delete
> > > > > > > > > > the
> > > > > > > > > > > > > > producer
> > > > > > > > > > > > > > > > > > > snapshots which have been copied to
> > remote
> > > > log
> > > > > > > segments
> > > > > > > > > > on
> > > > > > > > > > > > > > leader.
> > > > > > > > > > > > > > > > > > > Follower will keep the log segments
> > beyond
> > > > the
> > > > > > > segments
> > > > > > > > > > which
> > > > > > > > > > > > > > have not
> > > > > > > > > > > > > > > > > > > been copied to remote storage. We will
> > update
> > > > > the
> > > > > > > KIP
> > > > > > > > > > with
> > > > > > > > > > > > these
> > > > > > > > > > > > > > > > > > > details.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > > > > Satish.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > On Thu, Sep 17, 2020 at 1:47 AM Dhruvil
> > Shah
> > > > <
> > > > > > > > > > > > > > dhruvil@confluent.io>
> > > > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > Hi Satish, Harsha,
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > Thanks for the KIP. Few questions
> > below:
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > 1. Could you describe how retention
> > would
> > > > > work
> > > > > > > with
> > > > > > > > > > this
> > > > > > > > > > > > KIP
> > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > which
> > > > > > > > > > > > > > > > > > > > threads are responsible for driving
> > this
> > > > > work? I
> > > > > > > > > > believe
> > > > > > > > > > > > there
> > > > > > > > > > > > > > are 3
> > > > > > > > > > > > > > > > > > kinds
> > > > > > > > > > > > > > > > > > > > of retention processes we are looking
> > at:
> > > > > > > > > > > > > > > > > > > >   (a) Regular retention for data in
> > tiered
> > > > > > > storage as
> > > > > > > > > > per
> > > > > > > > > > > > > > configured
> > > > > > > > > > > > > > > > > `
> > > > > > > > > > > > > > > > > > > > retention.ms` / `retention.bytes`.
> > > > > > > > > > > > > > > > > > > >   (b) Local retention for data in local
> > > > > storage
> > > > > > > as
> > > > > > > > > per
> > > > > > > > > > > > > > configured `
> > > > > > > > > > > > > > > > > > > > local.log.retention.ms` /
> > > > > > > > > `local.log.retention.bytes`
> > > > > > > > > > > > > > > > > > > >   (c) Possibly regular retention for
> > data
> > > > in
> > > > > > > local
> > > > > > > > > > > > storage, if
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > tiering
> > > > > > > > > > > > > > > > > > > > task is lagging or for data that is
> > below
> > > > > the log
> > > > > > > > > start
> > > > > > > > > > > > offset.
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > 2. When does a segment become eligible
> > to
> > > > be
> > > > > > > tiered?
> > > > > > > > > > Is it
> > > > > > > > > > > > as
> > > > > > > > > > > > > > soon as
> > > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > > segment is rolled and the end offset is
> > > > less
> > > > > > > than the
> > > > > > > > > > last
> > > > > > > > > > > > > > stable
> > > > > > > > > > > > > > > > > > offset as
> > > > > > > > > > > > > > > > > > > > mentioned in the KIP? I wonder if we
> > need
> > > > to
> > > > > > > consider
> > > > > > > > > > other
> > > > > > > > > > > > > > > > > parameters
> > > > > > > > > > > > > > > > > > too,
> > > > > > > > > > > > > > > > > > > > like the highwatermark so that we are
> > > > > guaranteed
> > > > > > > that
> > > > > > > > > > what
> > > > > > > > > > > > we
> > > > > > > > > > > > > > are
> > > > > > > > > > > > > > > > > > tiering
> > > > > > > > > > > > > > > > > > > > has been committed to the log and
> > accepted
> > > > > by the
> > > > > > > > > ISR.
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > 3. The section on "Follower Fetch
> > > > Scenarios"
> > > > > is
> > > > > > > > > useful
> > > > > > > > > > but
> > > > > > > > > > > > is
> > > > > > > > > > > > > > a bit
> > > > > > > > > > > > > > > > > > > > difficult to parse at the moment. It
> > would
> > > > be
> > > > > > > useful
> > > > > > > > > to
> > > > > > > > > > > > > > summarize the
> > > > > > > > > > > > > > > > > > > > changes we need in the ReplicaFetcher.
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > 4. Related to the above, it's a bit
> > unclear
> > > > > how
> > > > > > > we
> > > > > > > > > are
> > > > > > > > > > > > > > planning on
> > > > > > > > > > > > > > > > > > > > restoring the producer state for a new
> > > > > replica.
> > > > > > > Could
> > > > > > > > > > you
> > > > > > > > > > > > > > expand on
> > > > > > > > > > > > > > > > > > that?
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > 5. Similarly, it would be worth
> > summarizing
> > > > > the
> > > > > > > > > > behavior on
> > > > > > > > > > > > > > unclean
> > > > > > > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > > > > > election. There are several scenarios
> > to
> > > > > consider
> > > > > > > > > here:
> > > > > > > > > > > > data
> > > > > > > > > > > > > > loss
> > > > > > > > > > > > > > > > > from
> > > > > > > > > > > > > > > > > > > > local log, data loss from remote log,
> > data
> > > > > loss
> > > > > > > from
> > > > > > > > > > > > metadata
> > > > > > > > > > > > > > topic,
> > > > > > > > > > > > > > > > > > etc.
> > > > > > > > > > > > > > > > > > > > It's worth describing these in detail.
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > 6. It would be useful to add details
> > about
> > > > > how we
> > > > > > > > > plan
> > > > > > > > > > on
> > > > > > > > > > > > using
> > > > > > > > > > > > > > > > > > RocksDB in
> > > > > > > > > > > > > > > > > > > > the default implementation of
> > > > > > > > > > `RemoteLogMetadataManager`.
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > 7. For a READ_COMMITTED FetchRequest,
> > how
> > > > do
> > > > > we
> > > > > > > > > > retrieve
> > > > > > > > > > > > and
> > > > > > > > > > > > > > return
> > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > > aborted transaction metadata?
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > 8. The `LogSegmentData` class assumes
> > that
> > > > we
> > > > > > > have a
> > > > > > > > > > log
> > > > > > > > > > > > > > segment,
> > > > > > > > > > > > > > > > > > offset
> > > > > > > > > > > > > > > > > > > > index, time index, transaction index,
> > > > > producer
> > > > > > > > > > snapshot and
> > > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > > > epoch
> > > > > > > > > > > > > > > > > > > > index. How do we deal with cases where
> > we
> > > > do
> > > > > not
> > > > > > > have
> > > > > > > > > > one
> > > > > > > > > > > > or
> > > > > > > > > > > > > > more of
> > > > > > > > > > > > > > > > > > these?
> > > > > > > > > > > > > > > > > > > > For example, we may not have a
> > transaction
> > > > > index
> > > > > > > or
> > > > > > > > > > > > producer
> > > > > > > > > > > > > > snapshot
> > > > > > > > > > > > > > > > > > for a
> > > > > > > > > > > > > > > > > > > > particular segment. The former is
> > optional,
> > > > > and
> > > > > > > the
> > > > > > > > > > latter
> > > > > > > > > > > > is
> > > > > > > > > > > > > > only
> > > > > > > > > > > > > > > > > > kept for
> > > > > > > > > > > > > > > > > > > > up to the 3 latest segments.
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > > > > > Dhruvil
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > On Mon, Sep 7, 2020 at 6:54 PM Harsha
> > Ch <
> > > > > > > > > > > > harsha.ch@gmail.com>
> > > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > Hi All,
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > We are all working through the last
> > > > meeting
> > > > > > > > > feedback.
> > > > > > > > > > > > I'll
> > > > > > > > > > > > > > cancel
> > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > > > tomorrow 's meeting and we can
> > meanwhile
> > > > > > > continue
> > > > > > > > > our
> > > > > > > > > > > > > > discussion in
> > > > > > > > > > > > > > > > > > mailing
> > > > > > > > > > > > > > > > > > > > > list. We can start the regular
> > meeting
> > > > from
> > > > > > > next
> > > > > > > > > week
> > > > > > > > > > > > > > onwards.
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > Harsha
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > On Fri, Sep 04, 2020 at 8:41 AM,
> > Satish
> > > > > > > Duggana <
> > > > > > > > > > > > > > > > > > satish.duggana@gmail.com
> > > > > > > > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > Hi Jun,
> > > > > > > > > > > > > > > > > > > > > > Thanks for your thorough review and
> > > > > comments.
> > > > > > > > > > Please
> > > > > > > > > > > > find
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > inline
> > > > > > > > > > > > > > > > > > > > > > replies below.
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > 600. The topic deletion logic needs
> > > > more
> > > > > > > details.
> > > > > > > > > > > > > > > > > > > > > > 600.1 The KIP mentions "The
> > controller
> > > > > > > considers
> > > > > > > > > > the
> > > > > > > > > > > > topic
> > > > > > > > > > > > > > > > > > partition is
> > > > > > > > > > > > > > > > > > > > > > deleted only when it determines
> > that
> > > > > there
> > > > > > > are no
> > > > > > > > > > log
> > > > > > > > > > > > > > segments
> > > > > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > > > that
> > > > > > > > > > > > > > > > > > > > > > topic partition by using RLMM".
> > How is
> > > > > this
> > > > > > > done?
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > It uses RLMM#listSegments()
> > returns all
> > > > > the
> > > > > > > > > > segments
> > > > > > > > > > > > for
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > given
> > > > > > > > > > > > > > > > > > topic
> > > > > > > > > > > > > > > > > > > > > > partition.
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > 600.2 "If the delete option is
> > enabled
> > > > > then
> > > > > > > the
> > > > > > > > > > leader
> > > > > > > > > > > > > > will stop
> > > > > > > > > > > > > > > > > > RLM task
> > > > > > > > > > > > > > > > > > > > > > and stop processing and it sets
> > all the
> > > > > > > remote
> > > > > > > > > log
> > > > > > > > > > > > segment
> > > > > > > > > > > > > > > > > > metadata of
> > > > > > > > > > > > > > > > > > > > > > that partition with a delete
> > marker and
> > > > > > > publishes
> > > > > > > > > > them
> > > > > > > > > > > > to
> > > > > > > > > > > > > > RLMM."
> > > > > > > > > > > > > > > > > We
> > > > > > > > > > > > > > > > > > > > > > discussed this earlier. When a
> > topic is
> > > > > being
> > > > > > > > > > deleted,
> > > > > > > > > > > > > > there may
> > > > > > > > > > > > > > > > > > not be a
> > > > > > > > > > > > > > > > > > > > > > leader for the deleted partition.
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > This is a good point. As suggested
> > in
> > > > the
> > > > > > > > > meeting,
> > > > > > > > > > we
> > > > > > > > > > > > will
> > > > > > > > > > > > > > add a
> > > > > > > > > > > > > > > > > > separate
> > > > > > > > > > > > > > > > > > > > > > section for topic/partition
> > deletion
> > > > > > > lifecycle
> > > > > > > > > and
> > > > > > > > > > this
> > > > > > > > > > > > > > scenario
> > > > > > > > > > > > > > > > > > will be
> > > > > > > > > > > > > > > > > > > > > > addressed.
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > 601. Unclean leader election
> > > > > > > > > > > > > > > > > > > > > > 601.1 Scenario 1: new empty
> > follower
> > > > > > > > > > > > > > > > > > > > > > After step 1, the follower
> > restores up
> > > > to
> > > > > > > offset
> > > > > > > > > > 3. So
> > > > > > > > > > > > why
> > > > > > > > > > > > > > does
> > > > > > > > > > > > > > > > > it
> > > > > > > > > > > > > > > > > > have
> > > > > > > > > > > > > > > > > > > > > > LE-2 <
> > > > > > > https://issues.apache.org/jira/browse/LE-2
> > > > > > > > > >
> > > > > > > > > > at
> > > > > > > > > > > > > > offset 5?
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > Nice catch. It was showing the
> > leader
> > > > > epoch
> > > > > > > > > fetched
> > > > > > > > > > > > from
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > > > > > > storage. It should be shown with
> > the
> > > > > > > truncated
> > > > > > > > > till
> > > > > > > > > > > > offset
> > > > > > > > > > > > > > 3.
> > > > > > > > > > > > > > > > > > Updated the
> > > > > > > > > > > > > > > > > > > > > > KIP.
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > 601.2 senario 5: After Step 3,
> > leader A
> > > > > has
> > > > > > > > > > > > inconsistent
> > > > > > > > > > > > > > data
> > > > > > > > > > > > > > > > > > between its
> > > > > > > > > > > > > > > > > > > > > > local and the tiered data. For
> > example.
> > > > > > > offset 3
> > > > > > > > > > has
> > > > > > > > > > > > msg 3
> > > > > > > > > > > > > > LE-0
> > > > > > > > > > > > > > > > > > <
> > https://issues.apache.org/jira/browse/LE-0>
> > > > > > > locally,
> > > > > > > > > > > > > > > > > > > > > > but msg 5 LE-1 <
> > > > > > > > > > > > https://issues.apache.org/jira/browse/LE-1>
> > > > > > > > > > > > > > in
> > > > > > > > > > > > > > > > > > the remote store. While it's ok for the
> > unclean
> > > > > > > leader
> > > > > > > > > > > > > > > > > > > > > > to lose data, it should still
> > return
> > > > > > > consistent
> > > > > > > > > > data,
> > > > > > > > > > > > > > whether
> > > > > > > > > > > > > > > > > it's
> > > > > > > > > > > > > > > > > > from
> > > > > > > > > > > > > > > > > > > > > > the local or the remote store.
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > There is no inconsistency here as
> > LE-0
> > > > > > > > > > > > > > > > > > <
> > https://issues.apache.org/jira/browse/LE-0>
> > > > > > > offsets are
> > > > > > > > > > [0,
> > > > > > > > > > > > 4]
> > > > > > > > > > > > > > and LE-2
> > > > > > > > > > > > > > > > > > <
> > https://issues.apache.org/jira/browse/LE-2>:
> > > > > > > > > > > > > > > > > > > > > > [5, ]. It will always get the right
> > > > > records
> > > > > > > for
> > > > > > > > > the
> > > > > > > > > > > > given
> > > > > > > > > > > > > > offset
> > > > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > > > > leader epoch. In case of remote,
> > RSM is
> > > > > > > invoked
> > > > > > > > > to
> > > > > > > > > > get
> > > > > > > > > > > > the
> > > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > > log
> > > > > > > > > > > > > > > > > > > > > > segment that contains the given
> > offset
> > > > > with
> > > > > > > the
> > > > > > > > > > leader
> > > > > > > > > > > > > > epoch.
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > 601.4 It seems that retention is
> > based
> > > > on
> > > > > > > > > > > > > > > > > > > > > >
> > listRemoteLogSegments(TopicPartition
> > > > > > > > > > topicPartition,
> > > > > > > > > > > > long
> > > > > > > > > > > > > > > > > > leaderEpoch).
> > > > > > > > > > > > > > > > > > > > > > When there is an unclean leader
> > > > election,
> > > > > > > it's
> > > > > > > > > > possible
> > > > > > > > > > > > > > for the
> > > > > > > > > > > > > > > > > new
> > > > > > > > > > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > > > > > > > to not to include certain epochs
> > in its
> > > > > epoch
> > > > > > > > > > cache.
> > > > > > > > > > > > How
> > > > > > > > > > > > > > are
> > > > > > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > > > > > > segments associated with those
> > epochs
> > > > > being
> > > > > > > > > > cleaned?
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > That is a good point. This leader
> > will
> > > > > also
> > > > > > > > > > cleanup the
> > > > > > > > > > > > > > epochs
> > > > > > > > > > > > > > > > > > earlier to
> > > > > > > > > > > > > > > > > > > > > > its start leader epoch and delete
> > those
> > > > > > > segments.
> > > > > > > > > > It
> > > > > > > > > > > > gets
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > earliest
> > > > > > > > > > > > > > > > > > > > > > epoch for a partition and starts
> > > > deleting
> > > > > > > > > segments
> > > > > > > > > > from
> > > > > > > > > > > > > > that
> > > > > > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > > > > > > epoch.
> > > > > > > > > > > > > > > > > > > > > > We need one more API in RLMM to
> > get the
> > > > > > > earliest
> > > > > > > > > > leader
> > > > > > > > > > > > > > epoch.
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > 601.5 The KIP discusses the
> > handling of
> > > > > > > unclean
> > > > > > > > > > leader
> > > > > > > > > > > > > > elections
> > > > > > > > > > > > > > > > > > for user
> > > > > > > > > > > > > > > > > > > > > > topics. What about unclean leader
> > > > > elections
> > > > > > > on
> > > > > > > > > > > > > > > > > > > > > > __remote_log_segment_metadata?
> > > > > > > > > > > > > > > > > > > > > > This is the same as other system
> > topics
> > > > > like
> > > > > > > > > > > > > > consumer_offsets,
> > > > > > > > > > > > > > > > > > > > > > __transaction_state topics. As
> > > > discussed
> > > > > in
> > > > > > > the
> > > > > > > > > > > > meeting,
> > > > > > > > > > > > > > we will
> > > > > > > > > > > > > > > > > > add the
> > > > > > > > > > > > > > > > > > > > > > behavior of
> > > > __remote_log_segment_metadata
> > > > > > > topic’s
> > > > > > > > > > > > unclean
> > > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > > > > > > > truncation.
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > 602. It would be useful to clarify
> > the
> > > > > > > > > limitations
> > > > > > > > > > in
> > > > > > > > > > > > the
> > > > > > > > > > > > > > initial
> > > > > > > > > > > > > > > > > > > > > release.
> > > > > > > > > > > > > > > > > > > > > > The KIP mentions not supporting
> > > > compacted
> > > > > > > topics.
> > > > > > > > > > What
> > > > > > > > > > > > > > about JBOD
> > > > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > > > > changing the configuration of a
> > topic
> > > > > from
> > > > > > > delete
> > > > > > > > > > to
> > > > > > > > > > > > > > compact
> > > > > > > > > > > > > > > > > after
> > > > > > > > > > > > > > > > > > > > > remote.
> > > > > > > > > > > > > > > > > > > > > > log. storage. enable (
> > > > > > > > > > > > http://remote.log.storage.enable/
> > > > > > > > > > > > > > ) is
> > > > > > > > > > > > > > > > > > enabled?
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > This was updated in the KIP
> > earlier.
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > 603. RLM leader tasks:
> > > > > > > > > > > > > > > > > > > > > > 603.1"It checks for rolled over
> > > > > LogSegments
> > > > > > > > > (which
> > > > > > > > > > have
> > > > > > > > > > > > > > the last
> > > > > > > > > > > > > > > > > > message
> > > > > > > > > > > > > > > > > > > > > > offset less than last stable
> > offset of
> > > > > that
> > > > > > > topic
> > > > > > > > > > > > > > partition) and
> > > > > > > > > > > > > > > > > > copies
> > > > > > > > > > > > > > > > > > > > > > them along with their
> > > > > offset/time/transaction
> > > > > > > > > > indexes
> > > > > > > > > > > > and
> > > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > > > epoch
> > > > > > > > > > > > > > > > > > > > > > cache to the remote tier." It
> > needs to
> > > > > copy
> > > > > > > the
> > > > > > > > > > > > producer
> > > > > > > > > > > > > > snapshot
> > > > > > > > > > > > > > > > > > too.
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > Right. It copies producer
> > snapshots too
> > > > > as
> > > > > > > > > > mentioned in
> > > > > > > > > > > > > > > > > > LogSegmentData.
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > 603.2 "Local logs are not cleaned
> > up
> > > > till
> > > > > > > those
> > > > > > > > > > > > segments
> > > > > > > > > > > > > > are
> > > > > > > > > > > > > > > > > copied
> > > > > > > > > > > > > > > > > > > > > > successfully to remote even though
> > > > their
> > > > > > > > > retention
> > > > > > > > > > > > > > time/size is
> > > > > > > > > > > > > > > > > > reached"
> > > > > > > > > > > > > > > > > > > > > > This seems weird. If the tiering
> > stops
> > > > > > > because
> > > > > > > > > the
> > > > > > > > > > > > remote
> > > > > > > > > > > > > > store
> > > > > > > > > > > > > > > > > is
> > > > > > > > > > > > > > > > > > not
> > > > > > > > > > > > > > > > > > > > > > available, we don't want the local
> > data
> > > > > to
> > > > > > > grow
> > > > > > > > > > > > forever.
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > It was clarified in the discussion
> > that
> > > > > the
> > > > > > > > > > comment was
> > > > > > > > > > > > > > more
> > > > > > > > > > > > > > > > > about
> > > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > > > > local storage goes beyond the
> > > > > log.retention.
> > > > > > > The
> > > > > > > > > > above
> > > > > > > > > > > > > > statement
> > > > > > > > > > > > > > > > > > is about
> > > > > > > > > > > > > > > > > > > > > > local.log.retention but not for the
> > > > > complete
> > > > > > > > > > > > > > log.retention. When
> > > > > > > > > > > > > > > > > it
> > > > > > > > > > > > > > > > > > > > > > reaches the log.retention then it
> > will
> > > > > > > delete the
> > > > > > > > > > local
> > > > > > > > > > > > > > logs even
> > > > > > > > > > > > > > > > > > though
> > > > > > > > > > > > > > > > > > > > > > those are not copied to remote
> > storage.
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > 604. "RLM maintains a bounded
> > > > > cache(possibly
> > > > > > > LRU)
> > > > > > > > > > of
> > > > > > > > > > > > the
> > > > > > > > > > > > > > index
> > > > > > > > > > > > > > > > > > files of
> > > > > > > > > > > > > > > > > > > > > > remote log segments to avoid
> > multiple
> > > > > index
> > > > > > > > > fetches
> > > > > > > > > > > > from
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > > > > > > storage. These indexes can be used
> > in
> > > > the
> > > > > > > same
> > > > > > > > > way
> > > > > > > > > > as
> > > > > > > > > > > > local
> > > > > > > > > > > > > > > > > segment
> > > > > > > > > > > > > > > > > > > > > > indexes are used." Could you
> > provide
> > > > more
> > > > > > > details
> > > > > > > > > > on
> > > > > > > > > > > > this?
> > > > > > > > > > > > > > Are
> > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > > > indexes
> > > > > > > > > > > > > > > > > > > > > > cached in memory or on disk? If on
> > > > disk,
> > > > > > > where
> > > > > > > > > are
> > > > > > > > > > they
> > > > > > > > > > > > > > stored?
> > > > > > > > > > > > > > > > > > Are the
> > > > > > > > > > > > > > > > > > > > > > cached indexes bound by a certain
> > size?
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > These are cached on disk and
> > stored in
> > > > > > > log.dir
> > > > > > > > > > with a
> > > > > > > > > > > > name
> > > > > > > > > > > > > > > > > > > > > > “__remote_log_index_cache”. They
> > are
> > > > > bound
> > > > > > > by the
> > > > > > > > > > total
> > > > > > > > > > > > > > size.
> > > > > > > > > > > > > > > > > This
> > > > > > > > > > > > > > > > > > will
> > > > > > > > > > > > > > > > > > > > > be
> > > > > > > > > > > > > > > > > > > > > > exposed as a user configuration,
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > 605. BuildingRemoteLogAux
> > > > > > > > > > > > > > > > > > > > > > 605.1 In this section, two options
> > are
> > > > > > > listed.
> > > > > > > > > > Which
> > > > > > > > > > > > one is
> > > > > > > > > > > > > > > > > chosen?
> > > > > > > > > > > > > > > > > > > > > > Option-2, updated the KIP.
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > 605.2 In option 2, it says "Build
> > the
> > > > > local
> > > > > > > > > leader
> > > > > > > > > > > > epoch
> > > > > > > > > > > > > > cache by
> > > > > > > > > > > > > > > > > > cutting
> > > > > > > > > > > > > > > > > > > > > > the leader epoch sequence received
> > from
> > > > > > > remote
> > > > > > > > > > storage
> > > > > > > > > > > > to
> > > > > > > > > > > > > > [LSO,
> > > > > > > > > > > > > > > > > > ELO].
> > > > > > > > > > > > > > > > > > > > > (LSO
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > = log start offset)." We need to
> > do the
> > > > > same
> > > > > > > > > thing
> > > > > > > > > > for
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > producer
> > > > > > > > > > > > > > > > > > > > > > snapshot. However, it's hard to
> > cut the
> > > > > > > producer
> > > > > > > > > > > > snapshot
> > > > > > > > > > > > > > to an
> > > > > > > > > > > > > > > > > > earlier
> > > > > > > > > > > > > > > > > > > > > > offset. Another option is to simply
> > > > take
> > > > > the
> > > > > > > > > > lastOffset
> > > > > > > > > > > > > > from the
> > > > > > > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > > > > > > segment and use that as the
> > starting
> > > > > fetch
> > > > > > > offset
> > > > > > > > > > in
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > follower.
> > > > > > > > > > > > > > > > > > This
> > > > > > > > > > > > > > > > > > > > > > avoids the need for cutting.
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > Right, this was mentioned in the
> > > > > > > “transactional
> > > > > > > > > > > > support”
> > > > > > > > > > > > > > section
> > > > > > > > > > > > > > > > > > about
> > > > > > > > > > > > > > > > > > > > > > adding these details.
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > 606. ListOffsets: Since we need a
> > > > version
> > > > > > > bump,
> > > > > > > > > > could
> > > > > > > > > > > > you
> > > > > > > > > > > > > > > > > document
> > > > > > > > > > > > > > > > > > it
> > > > > > > > > > > > > > > > > > > > > > under a protocol change section?
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > Sure, we will update the KIP.
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > 607. "LogStartOffset of a topic can
> > > > > point to
> > > > > > > > > > either of
> > > > > > > > > > > > > > local
> > > > > > > > > > > > > > > > > > segment or
> > > > > > > > > > > > > > > > > > > > > > remote segment but it is
> > initialised
> > > > and
> > > > > > > > > > maintained in
> > > > > > > > > > > > the
> > > > > > > > > > > > > > Log
> > > > > > > > > > > > > > > > > > class like
> > > > > > > > > > > > > > > > > > > > > > now. This is already maintained in
> > > > `Log`
> > > > > > > class
> > > > > > > > > > while
> > > > > > > > > > > > > > loading the
> > > > > > > > > > > > > > > > > > logs and
> > > > > > > > > > > > > > > > > > > > > > it can also be fetched from
> > > > > > > > > > RemoteLogMetadataManager."
> > > > > > > > > > > > > > What will
> > > > > > > > > > > > > > > > > > happen
> > > > > > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > > > > > the existing logic (e.g. log
> > recovery)
> > > > > that
> > > > > > > > > > currently
> > > > > > > > > > > > > > depends on
> > > > > > > > > > > > > > > > > > > > > > logStartOffset but assumes it's
> > local?
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > They use a field called
> > > > > localLogStartOffset
> > > > > > > which
> > > > > > > > > > is
> > > > > > > > > > > > the
> > > > > > > > > > > > > > local
> > > > > > > > > > > > > > > > > log
> > > > > > > > > > > > > > > > > > start
> > > > > > > > > > > > > > > > > > > > > > offset..
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > 608. Handle expired remote
> > segment: How
> > > > > does
> > > > > > > it
> > > > > > > > > > pick
> > > > > > > > > > > > up new
> > > > > > > > > > > > > > > > > > > > > logStartOffset
> > > > > > > > > > > > > > > > > > > > > > from deleteRecords?
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > Good point. This was not addressed
> > in
> > > > the
> > > > > > > KIP.
> > > > > > > > > Will
> > > > > > > > > > > > update
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > KIP
> > > > > > > > > > > > > > > > > > on how
> > > > > > > > > > > > > > > > > > > > > > the RLM task handles this scenario.
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > 609. RLMM message format:
> > > > > > > > > > > > > > > > > > > > > > 609.1 It includes both
> > MaxTimestamp and
> > > > > > > > > > EventTimestamp.
> > > > > > > > > > > > > > Where
> > > > > > > > > > > > > > > > > does
> > > > > > > > > > > > > > > > > > it get
> > > > > > > > > > > > > > > > > > > > > > both since the message in the log
> > only
> > > > > > > contains
> > > > > > > > > one
> > > > > > > > > > > > > > timestamp?
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > `EventTimeStamp` is the timestamp
> > at
> > > > > which
> > > > > > > that
> > > > > > > > > > segment
> > > > > > > > > > > > > > metadata
> > > > > > > > > > > > > > > > > > event is
> > > > > > > > > > > > > > > > > > > > > > generated. This is more for audits.
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > 609.2 If we change just the state
> > (e.g.
> > > > > to
> > > > > > > > > > > > > > DELETE_STARTED), it
> > > > > > > > > > > > > > > > > > seems it's
> > > > > > > > > > > > > > > > > > > > > > wasteful to have to include all
> > other
> > > > > fields
> > > > > > > not
> > > > > > > > > > > > changed.
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > This is a good point. We thought
> > about
> > > > > > > > > incremental
> > > > > > > > > > > > > > updates. But
> > > > > > > > > > > > > > > > > we
> > > > > > > > > > > > > > > > > > want
> > > > > > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > > > > > make sure all the events are in the
> > > > > expected
> > > > > > > > > order
> > > > > > > > > > and
> > > > > > > > > > > > take
> > > > > > > > > > > > > > > > > action
> > > > > > > > > > > > > > > > > > based
> > > > > > > > > > > > > > > > > > > > > > on the latest event. Will think
> > through
> > > > > the
> > > > > > > > > > approaches
> > > > > > > > > > > > in
> > > > > > > > > > > > > > detail
> > > > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > > > > update here.
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > 609.3 Could you document which
> > process
> > > > > makes
> > > > > > > the
> > > > > > > > > > > > following
> > > > > > > > > > > > > > > > > > transitions
> > > > > > > > > > > > > > > > > > > > > > DELETE_MARKED, DELETE_STARTED,
> > > > > > > DELETE_FINISHED?
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > Okay, will document more details.
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > 610.
> > > > remote.log.reader.max.pending.tasks:
> > > > > > > > > "Maximum
> > > > > > > > > > > > remote
> > > > > > > > > > > > > > log
> > > > > > > > > > > > > > > > > > reader
> > > > > > > > > > > > > > > > > > > > > > thread pool task queue size. If the
> > > > task
> > > > > > > queue is
> > > > > > > > > > full,
> > > > > > > > > > > > > > broker
> > > > > > > > > > > > > > > > > > will stop
> > > > > > > > > > > > > > > > > > > > > > reading remote log segments." What
> > does
> > > > > the
> > > > > > > > > broker
> > > > > > > > > > do
> > > > > > > > > > > > if
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > queue
> > > > > > > > > > > > > > > > > > is
> > > > > > > > > > > > > > > > > > > > > > full?
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > It returns an error for this topic
> > > > > partition.
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > 611. What do we return if the
> > request
> > > > > > > > > offset/epoch
> > > > > > > > > > > > doesn't
> > > > > > > > > > > > > > exist
> > > > > > > > > > > > > > > > > > in the
> > > > > > > > > > > > > > > > > > > > > > following API?
> > > > > > > > > > > > > > > > > > > > > > RemoteLogSegmentMetadata
> > > > > > > > > > > > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > > > > > > > > > > > > > > topicPartition, long offset, int
> > > > > > > epochForOffset)
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > This returns null. But we prefer to
> > > > > update
> > > > > > > the
> > > > > > > > > > return
> > > > > > > > > > > > type
> > > > > > > > > > > > > > as
> > > > > > > > > > > > > > > > > > Optional
> > > > > > > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > > > > return Empty if that does not
> > exist.
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > > > > > > > Satish.
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > On Tue, Sep 1, 2020 at 9:45 AM Jun
> > Rao
> > > > <
> > > > > jun@
> > > > > > > > > > > > confluent.
> > > > > > > > > > > > > > io (
> > > > > > > > > > > > > > > > > > > > > > jun@confluent.io ) > wrote:
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >> Hi, Satish,
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >> Thanks for the updated KIP. Made
> > > > another
> > > > > > > pass. A
> > > > > > > > > > few
> > > > > > > > > > > > more
> > > > > > > > > > > > > > > > > comments
> > > > > > > > > > > > > > > > > > > > > below.
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >> 600. The topic deletion logic
> > needs
> > > > more
> > > > > > > > > details.
> > > > > > > > > > > > > > > > > > > > > >> 600.1 The KIP mentions "The
> > controller
> > > > > > > considers
> > > > > > > > > > the
> > > > > > > > > > > > topic
> > > > > > > > > > > > > > > > > > partition is
> > > > > > > > > > > > > > > > > > > > > >> deleted only when it determines
> > that
> > > > > there
> > > > > > > are
> > > > > > > > > no
> > > > > > > > > > log
> > > > > > > > > > > > > > segments
> > > > > > > > > > > > > > > > > > for that
> > > > > > > > > > > > > > > > > > > > > >> topic partition by using RLMM".
> > How is
> > > > > this
> > > > > > > > > done?
> > > > > > > > > > > > 600.2
> > > > > > > > > > > > > > "If the
> > > > > > > > > > > > > > > > > > delete
> > > > > > > > > > > > > > > > > > > > > >> option is enabled then the leader
> > will
> > > > > stop
> > > > > > > RLM
> > > > > > > > > > task
> > > > > > > > > > > > and
> > > > > > > > > > > > > > stop
> > > > > > > > > > > > > > > > > > processing
> > > > > > > > > > > > > > > > > > > > > >> and it sets all the remote log
> > segment
> > > > > > > metadata
> > > > > > > > > of
> > > > > > > > > > > > that
> > > > > > > > > > > > > > > > > partition
> > > > > > > > > > > > > > > > > > with a
> > > > > > > > > > > > > > > > > > > > > >> delete marker and publishes them
> > to
> > > > > RLMM."
> > > > > > > We
> > > > > > > > > > > > discussed
> > > > > > > > > > > > > > this
> > > > > > > > > > > > > > > > > > earlier.
> > > > > > > > > > > > > > > > > > > > > When
> > > > > > > > > > > > > > > > > > > > > >> a topic is being deleted, there
> > may
> > > > not
> > > > > be a
> > > > > > > > > > leader
> > > > > > > > > > > > for
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > deleted
> > > > > > > > > > > > > > > > > > > > > >> partition.
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >> 601. Unclean leader election
> > > > > > > > > > > > > > > > > > > > > >> 601.1 Scenario 1: new empty
> > follower
> > > > > > > > > > > > > > > > > > > > > >> After step 1, the follower
> > restores up
> > > > > to
> > > > > > > offset
> > > > > > > > > > 3. So
> > > > > > > > > > > > > > why does
> > > > > > > > > > > > > > > > > > it have
> > > > > > > > > > > > > > > > > > > > > >> LE-2 <
> > > > > > > > > https://issues.apache.org/jira/browse/LE-2>
> > > > > > > > > > at
> > > > > > > > > > > > > > offset 5?
> > > > > > > > > > > > > > > > > > > > > >> 601.2 senario 5: After Step 3,
> > leader
> > > > A
> > > > > has
> > > > > > > > > > > > inconsistent
> > > > > > > > > > > > > > data
> > > > > > > > > > > > > > > > > > between
> > > > > > > > > > > > > > > > > > > > > its
> > > > > > > > > > > > > > > > > > > > > >> local and the tiered data. For
> > > > example.
> > > > > > > offset 3
> > > > > > > > > > has
> > > > > > > > > > > > msg
> > > > > > > > > > > > > > 3 LE-0
> > > > > > > > > > > > > > > > > > <
> > https://issues.apache.org/jira/browse/LE-0>
> > > > > > > locally,
> > > > > > > > > > > > > > > > > > > > > >> but msg 5 LE-1 <
> > > > > > > > > > > > > > https://issues.apache.org/jira/browse/LE-1> in
> > > > > > > > > > > > > > > > > > the remote store. While it's ok for the
> > unclean
> > > > > > > leader
> > > > > > > > > > > > > > > > > > > > > >> to lose data, it should still
> > return
> > > > > > > consistent
> > > > > > > > > > data,
> > > > > > > > > > > > > > whether
> > > > > > > > > > > > > > > > > > it's from
> > > > > > > > > > > > > > > > > > > > > >> the local or the remote store.
> > > > > > > > > > > > > > > > > > > > > >> 601.3 The follower picks up log
> > start
> > > > > offset
> > > > > > > > > > using the
> > > > > > > > > > > > > > following
> > > > > > > > > > > > > > > > > > api.
> > > > > > > > > > > > > > > > > > > > > >> Suppose that we have 3 remote
> > segments
> > > > > (LE,
> > > > > > > > > > > > > > SegmentStartOffset)
> > > > > > > > > > > > > > > > > > as (2,
> > > > > > > > > > > > > > > > > > > > > >> 10),
> > > > > > > > > > > > > > > > > > > > > >> (3, 20) and (7, 15) due to an
> > unclean
> > > > > leader
> > > > > > > > > > election.
> > > > > > > > > > > > > > Using the
> > > > > > > > > > > > > > > > > > > > > following
> > > > > > > > > > > > > > > > > > > > > >> api will cause logStartOffset to
> > go
> > > > > backward
> > > > > > > > > from
> > > > > > > > > > 20
> > > > > > > > > > > > to
> > > > > > > > > > > > > > 15. How
> > > > > > > > > > > > > > > > > > do we
> > > > > > > > > > > > > > > > > > > > > >> prevent that?
> > > > > > > > > > > > > > > > > > > > > >> earliestLogOffset(TopicPartition
> > > > > > > topicPartition,
> > > > > > > > > > int
> > > > > > > > > > > > > > > > > leaderEpoch)
> > > > > > > > > > > > > > > > > > 601.4
> > > > > > > > > > > > > > > > > > > > > It
> > > > > > > > > > > > > > > > > > > > > >> seems that retention is based on
> > > > > > > > > > > > > > > > > > > > > >>
> > listRemoteLogSegments(TopicPartition
> > > > > > > > > > topicPartition,
> > > > > > > > > > > > long
> > > > > > > > > > > > > > > > > > leaderEpoch).
> > > > > > > > > > > > > > > > > > > > > >> When there is an unclean leader
> > > > > election,
> > > > > > > it's
> > > > > > > > > > > > possible
> > > > > > > > > > > > > > for the
> > > > > > > > > > > > > > > > > > new
> > > > > > > > > > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > > > > > > >> to not to include certain epochs
> > in
> > > > its
> > > > > > > epoch
> > > > > > > > > > cache.
> > > > > > > > > > > > How
> > > > > > > > > > > > > > are
> > > > > > > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > > > > > >> segments associated with those
> > epochs
> > > > > being
> > > > > > > > > > cleaned?
> > > > > > > > > > > > > > 601.5 The
> > > > > > > > > > > > > > > > > KIP
> > > > > > > > > > > > > > > > > > > > > >> discusses the handling of unclean
> > > > leader
> > > > > > > > > > elections for
> > > > > > > > > > > > > > user
> > > > > > > > > > > > > > > > > > topics. What
> > > > > > > > > > > > > > > > > > > > > >> about unclean leader elections on
> > > > > > > > > > > > > > > > > > > > > >> __remote_log_segment_metadata?
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >> 602. It would be useful to
> > clarify the
> > > > > > > > > > limitations in
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > initial
> > > > > > > > > > > > > > > > > > > > > release.
> > > > > > > > > > > > > > > > > > > > > >> The KIP mentions not supporting
> > > > > compacted
> > > > > > > > > topics.
> > > > > > > > > > What
> > > > > > > > > > > > > > about
> > > > > > > > > > > > > > > > > JBOD
> > > > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > > > >> changing the configuration of a
> > topic
> > > > > from
> > > > > > > > > delete
> > > > > > > > > > to
> > > > > > > > > > > > > > compact
> > > > > > > > > > > > > > > > > after
> > > > > > > > > > > > > > > > > > > > > remote.
> > > > > > > > > > > > > > > > > > > > > >> log. storage. enable (
> > > > > > > > > > > > http://remote.log.storage.enable/
> > > > > > > > > > > > > > ) is
> > > > > > > > > > > > > > > > > > enabled?
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >> 603. RLM leader tasks:
> > > > > > > > > > > > > > > > > > > > > >> 603.1"It checks for rolled over
> > > > > LogSegments
> > > > > > > > > (which
> > > > > > > > > > > > have
> > > > > > > > > > > > > > the last
> > > > > > > > > > > > > > > > > > message
> > > > > > > > > > > > > > > > > > > > > >> offset less than last stable
> > offset of
> > > > > that
> > > > > > > > > topic
> > > > > > > > > > > > > > partition) and
> > > > > > > > > > > > > > > > > > copies
> > > > > > > > > > > > > > > > > > > > > >> them along with their
> > > > > > > offset/time/transaction
> > > > > > > > > > indexes
> > > > > > > > > > > > and
> > > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > > > epoch
> > > > > > > > > > > > > > > > > > > > > >> cache to the remote tier." It
> > needs to
> > > > > copy
> > > > > > > the
> > > > > > > > > > > > producer
> > > > > > > > > > > > > > > > > snapshot
> > > > > > > > > > > > > > > > > > too.
> > > > > > > > > > > > > > > > > > > > > >> 603.2 "Local logs are not cleaned
> > up
> > > > > till
> > > > > > > those
> > > > > > > > > > > > segments
> > > > > > > > > > > > > > are
> > > > > > > > > > > > > > > > > > copied
> > > > > > > > > > > > > > > > > > > > > >> successfully to remote even though
> > > > their
> > > > > > > > > retention
> > > > > > > > > > > > > > time/size is
> > > > > > > > > > > > > > > > > > reached"
> > > > > > > > > > > > > > > > > > > > > >> This seems weird. If the tiering
> > stops
> > > > > > > because
> > > > > > > > > the
> > > > > > > > > > > > remote
> > > > > > > > > > > > > > store
> > > > > > > > > > > > > > > > > > is not
> > > > > > > > > > > > > > > > > > > > > >> available, we don't want the local
> > > > data
> > > > > to
> > > > > > > grow
> > > > > > > > > > > > forever.
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >> 604. "RLM maintains a bounded
> > > > > cache(possibly
> > > > > > > > > LRU)
> > > > > > > > > > of
> > > > > > > > > > > > the
> > > > > > > > > > > > > > index
> > > > > > > > > > > > > > > > > > files of
> > > > > > > > > > > > > > > > > > > > > >> remote log segments to avoid
> > multiple
> > > > > index
> > > > > > > > > > fetches
> > > > > > > > > > > > from
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > > > > > >> storage. These indexes can be
> > used in
> > > > > the
> > > > > > > same
> > > > > > > > > > way as
> > > > > > > > > > > > > > local
> > > > > > > > > > > > > > > > > > segment
> > > > > > > > > > > > > > > > > > > > > >> indexes are used." Could you
> > provide
> > > > > more
> > > > > > > > > details
> > > > > > > > > > on
> > > > > > > > > > > > > > this? Are
> > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > > > indexes
> > > > > > > > > > > > > > > > > > > > > >> cached in memory or on disk? If on
> > > > disk,
> > > > > > > where
> > > > > > > > > are
> > > > > > > > > > > > they
> > > > > > > > > > > > > > stored?
> > > > > > > > > > > > > > > > > > Are the
> > > > > > > > > > > > > > > > > > > > > >> cached indexes bound by a certain
> > > > size?
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >> 605. BuildingRemoteLogAux
> > > > > > > > > > > > > > > > > > > > > >> 605.1 In this section, two
> > options are
> > > > > > > listed.
> > > > > > > > > > Which
> > > > > > > > > > > > one
> > > > > > > > > > > > > > is
> > > > > > > > > > > > > > > > > > chosen?
> > > > > > > > > > > > > > > > > > > > > 605.2
> > > > > > > > > > > > > > > > > > > > > >> In option 2, it says "Build the
> > local
> > > > > leader
> > > > > > > > > epoch
> > > > > > > > > > > > cache
> > > > > > > > > > > > > > by
> > > > > > > > > > > > > > > > > > cutting the
> > > > > > > > > > > > > > > > > > > > > >> leader epoch sequence received
> > from
> > > > > remote
> > > > > > > > > > storage to
> > > > > > > > > > > > > > [LSO,
> > > > > > > > > > > > > > > > > ELO].
> > > > > > > > > > > > > > > > > > (LSO
> > > > > > > > > > > > > > > > > > > > > >> = log start offset)." We need to
> > do
> > > > the
> > > > > same
> > > > > > > > > thing
> > > > > > > > > > > > for the
> > > > > > > > > > > > > > > > > > producer
> > > > > > > > > > > > > > > > > > > > > >> snapshot. However, it's hard to
> > cut
> > > > the
> > > > > > > producer
> > > > > > > > > > > > snapshot
> > > > > > > > > > > > > > to an
> > > > > > > > > > > > > > > > > > earlier
> > > > > > > > > > > > > > > > > > > > > >> offset. Another option is to
> > simply
> > > > > take the
> > > > > > > > > > > > lastOffset
> > > > > > > > > > > > > > from the
> > > > > > > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > > > > > >> segment and use that as the
> > starting
> > > > > fetch
> > > > > > > > > offset
> > > > > > > > > > in
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > follower. This
> > > > > > > > > > > > > > > > > > > > > >> avoids the need for cutting.
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >> 606. ListOffsets: Since we need a
> > > > > version
> > > > > > > bump,
> > > > > > > > > > could
> > > > > > > > > > > > you
> > > > > > > > > > > > > > > > > > document it
> > > > > > > > > > > > > > > > > > > > > >> under a protocol change section?
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >> 607. "LogStartOffset of a topic
> > can
> > > > > point to
> > > > > > > > > > either of
> > > > > > > > > > > > > > local
> > > > > > > > > > > > > > > > > > segment or
> > > > > > > > > > > > > > > > > > > > > >> remote segment but it is
> > initialised
> > > > and
> > > > > > > > > > maintained in
> > > > > > > > > > > > > > the Log
> > > > > > > > > > > > > > > > > > class
> > > > > > > > > > > > > > > > > > > > > like
> > > > > > > > > > > > > > > > > > > > > >> now. This is already maintained in
> > > > `Log`
> > > > > > > class
> > > > > > > > > > while
> > > > > > > > > > > > > > loading the
> > > > > > > > > > > > > > > > > > logs
> > > > > > > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > > > >> it can also be fetched from
> > > > > > > > > > RemoteLogMetadataManager."
> > > > > > > > > > > > > > What will
> > > > > > > > > > > > > > > > > > happen
> > > > > > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > > > > >> the existing logic (e.g. log
> > recovery)
> > > > > that
> > > > > > > > > > currently
> > > > > > > > > > > > > > depends on
> > > > > > > > > > > > > > > > > > > > > >> logStartOffset but assumes it's
> > local?
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >> 608. Handle expired remote
> > segment:
> > > > How
> > > > > > > does it
> > > > > > > > > > pick
> > > > > > > > > > > > up
> > > > > > > > > > > > > > new
> > > > > > > > > > > > > > > > > > > > > logStartOffset
> > > > > > > > > > > > > > > > > > > > > >> from deleteRecords?
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >> 609. RLMM message format:
> > > > > > > > > > > > > > > > > > > > > >> 609.1 It includes both
> > MaxTimestamp
> > > > and
> > > > > > > > > > > > EventTimestamp.
> > > > > > > > > > > > > > Where
> > > > > > > > > > > > > > > > > > does it
> > > > > > > > > > > > > > > > > > > > > get
> > > > > > > > > > > > > > > > > > > > > >> both since the message in the log
> > only
> > > > > > > contains
> > > > > > > > > > one
> > > > > > > > > > > > > > timestamp?
> > > > > > > > > > > > > > > > > > 609.2 If
> > > > > > > > > > > > > > > > > > > > > we
> > > > > > > > > > > > > > > > > > > > > >> change just the state (e.g. to
> > > > > > > DELETE_STARTED),
> > > > > > > > > it
> > > > > > > > > > > > seems
> > > > > > > > > > > > > > it's
> > > > > > > > > > > > > > > > > > wasteful
> > > > > > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > > > > >> have to include all other fields
> > not
> > > > > > > changed.
> > > > > > > > > > 609.3
> > > > > > > > > > > > Could
> > > > > > > > > > > > > > you
> > > > > > > > > > > > > > > > > > document
> > > > > > > > > > > > > > > > > > > > > >> which process makes the following
> > > > > > > transitions
> > > > > > > > > > > > > > DELETE_MARKED,
> > > > > > > > > > > > > > > > > > > > > >> DELETE_STARTED, DELETE_FINISHED?
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >> 610.
> > > > > remote.log.reader.max.pending.tasks:
> > > > > > > > > "Maximum
> > > > > > > > > > > > remote
> > > > > > > > > > > > > > log
> > > > > > > > > > > > > > > > > > reader
> > > > > > > > > > > > > > > > > > > > > >> thread pool task queue size. If
> > the
> > > > task
> > > > > > > queue
> > > > > > > > > is
> > > > > > > > > > > > full,
> > > > > > > > > > > > > > broker
> > > > > > > > > > > > > > > > > > will stop
> > > > > > > > > > > > > > > > > > > > > >> reading remote log segments." What
> > > > does
> > > > > the
> > > > > > > > > > broker do
> > > > > > > > > > > > if
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > queue is
> > > > > > > > > > > > > > > > > > > > > >> full?
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >> 611. What do we return if the
> > request
> > > > > > > > > offset/epoch
> > > > > > > > > > > > > > doesn't exist
> > > > > > > > > > > > > > > > > > in the
> > > > > > > > > > > > > > > > > > > > > >> following API?
> > > > > > > > > > > > > > > > > > > > > >> RemoteLogSegmentMetadata
> > > > > > > > > > > > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > > > > > > > > > > > > > >> topicPartition, long offset, int
> > > > > > > epochForOffset)
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >> Jun
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >> On Mon, Aug 31, 2020 at 11:19 AM
> > > > Satish
> > > > > > > Duggana
> > > > > > > > > <
> > > > > > > > > > > > satish.
> > > > > > > > > > > > > > > > > duggana@
> > > > > > > > > > > > > > > > > > > > > gmail. com
> > > > > > > > > > > > > > > > > > > > > >> ( satish.duggana@gmail.com ) >
> > wrote:
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>> KIP is updated with
> > > > > > > > > > > > > > > > > > > > > >>> - Remote log segment metadata
> > topic
> > > > > message
> > > > > > > > > > > > > > format/schema.
> > > > > > > > > > > > > > > > > > > > > >>> - Added remote log segment
> > metadata
> > > > > state
> > > > > > > > > > > > transitions and
> > > > > > > > > > > > > > > > > > explained how
> > > > > > > > > > > > > > > > > > > > > >>> the deletion of segments is
> > handled,
> > > > > > > including
> > > > > > > > > > the
> > > > > > > > > > > > case
> > > > > > > > > > > > > > of
> > > > > > > > > > > > > > > > > > partition
> > > > > > > > > > > > > > > > > > > > > >>> deletions.
> > > > > > > > > > > > > > > > > > > > > >>> - Added a few more limitations
> > in the
> > > > > "Non
> > > > > > > > > goals"
> > > > > > > > > > > > > > section.
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>> Thanks,
> > > > > > > > > > > > > > > > > > > > > >>> Satish.
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>> On Thu, Aug 27, 2020 at 12:42 AM
> > > > > Harsha Ch
> > > > > > > <
> > > > > > > > > > harsha.
> > > > > > > > > > > > ch@
> > > > > > > > > > > > > > > > > gmail.
> > > > > > > > > > > > > > > > > > com (
> > > > > > > > > > > > > > > > > > > > > >>> harsha.ch@gmail.com ) > wrote:
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>> Updated the KIP with Meeting
> > Notes
> > > > > section
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>> https:/ / cwiki. apache. org/
> > > > > confluence/
> > > > > > > > > > display/
> > > > > > > > > > > > KAFKA/
> > > > > > > > > > > > > > > > > > > > > KIP-405 <
> > > > > > > > > > https://issues.apache.org/jira/browse/KIP-405>
> > > > > > > > > > > > > > > > > >
> > > > > > > > > >
> > %3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> > > > > > > > > > > > > > > > > > > > > >>> (
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > >
> > > > >
> > > >
> > https://cwiki.apache.org/confluence/display/KAFKA/KIP-405%3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> > > > > > > > > > > > > > > > > > > > > >>> )
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>> On Tue, Aug 25, 2020 at 1:03 PM
> > Jun
> > > > > Rao <
> > > > > > > jun@
> > > > > > > > > > > > > > confluent. io
> > > > > > > > > > > > > > > > > (
> > > > > > > > > > > > > > > > > > > > > >>>> jun@confluent.io ) > wrote:
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>> Hi, Harsha,
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>> Thanks for the summary. Could
> > you
> > > > > add the
> > > > > > > > > > summary
> > > > > > > > > > > > and
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > recording
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>> link to
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>> the last section of
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>> https:/ / cwiki. apache. org/
> > > > > confluence/
> > > > > > > > > > display/
> > > > > > > > > > > > KAFKA/
> > > > > > > > > > > > > > > > > > > > > Kafka+Improvement+Proposals
> > > > > > > > > > > > > > > > > > > > > >>> (
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > >
> > > > >
> > > >
> > https://cwiki.apache.org/confluence/display/KAFKA/Kafka+Improvement+Proposals
> > > > > > > > > > > > > > > > > > > > > >>> )
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>> ?
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>> Jun
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>> On Tue, Aug 25, 2020 at 11:12
> > AM
> > > > > Harsha
> > > > > > > > > > > > Chintalapani <
> > > > > > > > > > > > > > kafka@
> > > > > > > > > > > > > > > > > > > > > harsha. io (
> > > > > > > > > > > > > > > > > > > > > >>>>> kafka@harsha.io ) > wrote:
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>> Thanks everyone for attending
> > the
> > > > > > > meeting
> > > > > > > > > > today.
> > > > > > > > > > > > > > > > > > > > > >>>>>> Here is the recording
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>> https:/ / drive. google. com/
> > file/
> > > > d/
> > > > > > > > > > > > > > > > > > > > > 14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/
> > > > > > > view?usp=sharing
> > > > > > > > > > > > > > > > > > > > > >>> (
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > >
> > > > >
> > > >
> > https://drive.google.com/file/d/14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/view?usp=sharing
> > > > > > > > > > > > > > > > > > > > > >>> )
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>> Notes:
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>> 1. KIP is updated with
> > follower
> > > > > fetch
> > > > > > > > > > protocol and
> > > > > > > > > > > > > > ready to
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>> reviewed
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>> 2. Satish to capture schema of
> > > > > internal
> > > > > > > > > > metadata
> > > > > > > > > > > > > > topic in
> > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > KIP
> > > > > > > > > > > > > > > > > > > > > >>>>>> 3. We will update the KIP with
> > > > > details
> > > > > > > of
> > > > > > > > > > > > different
> > > > > > > > > > > > > > cases
> > > > > > > > > > > > > > > > > > > > > >>>>>> 4. Test plan will be captured
> > in a
> > > > > doc
> > > > > > > and
> > > > > > > > > > will
> > > > > > > > > > > > add
> > > > > > > > > > > > > > to the
> > > > > > > > > > > > > > > > > KIP
> > > > > > > > > > > > > > > > > > > > > >>>>>> 5. Add a section
> > "Limitations" to
> > > > > > > capture
> > > > > > > > > the
> > > > > > > > > > > > > > capabilities
> > > > > > > > > > > > > > > > > > that
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>> will
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>> be
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>> introduced with this KIP and
> > what
> > > > > will
> > > > > > > not
> > > > > > > > > be
> > > > > > > > > > > > covered
> > > > > > > > > > > > > > in
> > > > > > > > > > > > > > > > > this
> > > > > > > > > > > > > > > > > > KIP.
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>> Please add to it I missed
> > > > anything.
> > > > > Will
> > > > > > > > > > produce a
> > > > > > > > > > > > > > formal
> > > > > > > > > > > > > > > > > > meeting
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>> notes
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>> from next meeting onwards.
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>> Thanks,
> > > > > > > > > > > > > > > > > > > > > >>>>>> Harsha
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>> On Mon, Aug 24, 2020 at 9:42
> > PM,
> > > > > Ying
> > > > > > > Zheng
> > > > > > > > > <
> > > > > > > > > > > > yingz@
> > > > > > > > > > > > > > uber.
> > > > > > > > > > > > > > > > > > com.
> > > > > > > > > > > > > > > > > > > > > invalid (
> > > > > > > > > > > > > > > > > > > > > >>>>>> yingz@uber.com.invalid ) >
> > wrote:
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> We did some basic feature
> > tests
> > > > at
> > > > > > > Uber.
> > > > > > > > > The
> > > > > > > > > > test
> > > > > > > > > > > > > > cases and
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>> results are
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> shared in this google doc:
> > > > > > > > > > > > > > > > > > > > > >>>>>>> https:/ / docs. google. com/
> > > > > > > spreadsheets/
> > > > > > > > > > d/ (
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > https://docs.google.com/spreadsheets/d/ )
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >
> > > > > > > > > 1XhNJqjzwXvMCcAOhEH0sSXU6RTvyoSf93DHF-YMfGLk/edit?usp=sharing
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> The performance test results
> > were
> > > > > > > already
> > > > > > > > > > shared
> > > > > > > > > > > > in
> > > > > > > > > > > > > > the KIP
> > > > > > > > > > > > > > > > > > last
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>> month.
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> On Mon, Aug 24, 2020 at
> > 11:10 AM
> > > > > > > Harsha Ch
> > > > > > > > > <
> > > > > > > > > > > > harsha.
> > > > > > > > > > > > > > ch@
> > > > > > > > > > > > > > > > > > gmail.
> > > > > > > > > > > > > > > > > > > > > com (
> > > > > > > > > > > > > > > > > > > > > >>>>>>> harsha.ch@gmail.com ) >
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>> wrote:
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> "Understand commitments
> > towards
> > > > > driving
> > > > > > > > > > design &
> > > > > > > > > > > > > > > > > > implementation of
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>> the
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>> KIP
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> further and how it aligns
> > with
> > > > > > > participant
> > > > > > > > > > > > interests
> > > > > > > > > > > > > > in
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>> contributing to
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>> the
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> efforts (ex: in the context
> > of
> > > > > Uber’s
> > > > > > > Q3/Q4
> > > > > > > > > > > > > > roadmap)." What
> > > > > > > > > > > > > > > > > > is that
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>> about?
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> On Mon, Aug 24, 2020 at
> > 11:05 AM
> > > > > > > Kowshik
> > > > > > > > > > > > Prakasam <
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>> kprakasam@ confluent. io (
> > > > > > > > > > kprakasam@confluent.io
> > > > > > > > > > > > ) >
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> wrote:
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> Hi Harsha,
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> The following google doc
> > > > contains a
> > > > > > > > > proposal
> > > > > > > > > > for
> > > > > > > > > > > > > > temporary
> > > > > > > > > > > > > > > > > > agenda
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>> for
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>> the
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> KIP-405 <
> > > > > > > > > > > > > > https://issues.apache.org/jira/browse/KIP-405> <
> > > > > > > > > > > > > > > > > > https:/ / issues. apache. org/ jira/
> > browse/
> > > > > KIP-405
> > > > > > > > > > > > > > > > > > <
> > https://issues.apache.org/jira/browse/KIP-405
> > > > >
> > > > > (
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > https://issues.apache.org/jira/browse/KIP-405 )
> > > > > > > > > > > > >
> > > > > > > > > > > > > > sync
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>> meeting
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> tomorrow:
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> https:/ / docs. google. com/
> > > > > document/
> > > > > > > d/ (
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > https://docs.google.com/document/d/ )
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > 1pqo8X5LU8TpwfC_iqSuVPezhfCfhGkbGN2TqiPA3LBU/edit
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> .
> > > > > > > > > > > > > > > > > > > > > >>>>>>> Please could you add it to
> > the
> > > > > Google
> > > > > > > > > > calendar
> > > > > > > > > > > > > > invite?
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> Thank you.
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> Cheers,
> > > > > > > > > > > > > > > > > > > > > >>>>>>> Kowshik
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> On Thu, Aug 20, 2020 at
> > 10:58 AM
> > > > > > > Harsha Ch
> > > > > > > > > <
> > > > > > > > > > > > harsha.
> > > > > > > > > > > > > > ch@
> > > > > > > > > > > > > > > > > > gmail.
> > > > > > > > > > > > > > > > > > > > > com (
> > > > > > > > > > > > > > > > > > > > > >>>>>>> harsha.ch@gmail.com ) >
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>> wrote:
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> Hi All,
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> Scheduled a meeting for
> > Tuesday
> > > > > 9am -
> > > > > > > 10am.
> > > > > > > > > > I can
> > > > > > > > > > > > > > record
> > > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>> upload for
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> community to be able to
> > follow
> > > > the
> > > > > > > > > > discussion.
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> Jun, please add the required
> > > > folks
> > > > > on
> > > > > > > > > > confluent
> > > > > > > > > > > > side.
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> Thanks,
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> Harsha
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> On Thu, Aug 20, 2020 at
> > 12:33 AM,
> > > > > > > Alexandre
> > > > > > > > > > > > Dupriez <
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>> alexandre.dupriez@
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> gmail. com (
> > http://gmail.com/
> > > > ) >
> > > > > > > wrote:
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> Hi Jun,
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> Many thanks for your
> > initiative.
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> If you like, I am happy to
> > attend
> > > > > at
> > > > > > > the
> > > > > > > > > > time you
> > > > > > > > > > > > > > > > > suggested.
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> Many thanks,
> > > > > > > > > > > > > > > > > > > > > >>>>>>> Alexandre
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> Le mer. 19 août 2020 à 22:00,
> > > > > Harsha
> > > > > > > Ch <
> > > > > > > > > > > > harsha. ch@
> > > > > > > > > > > > > > > > > > gmail. com (
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>> harsha.
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> ch@ gmail. com (
> > ch@gmail.com )
> > > > )
> > > > > > a
> > > > > > > > > écrit
> > > > > > > > > > :
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> Hi Jun,
> > > > > > > > > > > > > > > > > > > > > >>>>>>> Thanks. This will help a lot.
> > > > > Tuesday
> > > > > > > will
> > > > > > > > > > work
> > > > > > > > > > > > for
> > > > > > > > > > > > > > us.
> > > > > > > > > > > > > > > > > > > > > >>>>>>> -Harsha
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> On Wed, Aug 19, 2020 at 1:24
> > PM
> > > > Jun
> > > > > > > Rao <
> > > > > > > > > > jun@
> > > > > > > > > > > > > > confluent.
> > > > > > > > > > > > > > > > > > io (
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>> jun@
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> confluent. io (
> > > > > http://confluent.io/
> > > > > > > ) ) >
> > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> Hi, Satish, Ying, Harsha,
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> Do you think it would be
> > useful
> > > > to
> > > > > > > have a
> > > > > > > > > > regular
> > > > > > > > > > > > > > virtual
> > > > > > > > > > > > > > > > > > meeting
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>> to
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> discuss this KIP? The goal
> > of the
> > > > > > > meeting
> > > > > > > > > > will be
> > > > > > > > > > > > > > sharing
> > > > > > > > > > > > > > > > > > > > > >>>>>>> design/development progress
> > and
> > > > > > > discussing
> > > > > > > > > > any
> > > > > > > > > > > > open
> > > > > > > > > > > > > > issues
> > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> accelerate
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> this KIP. If so, will every
> > > > Tuesday
> > > > > > > (from
> > > > > > > > > > next
> > > > > > > > > > > > week)
> > > > > > > > > > > > > > > > > 9am-10am
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> PT
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> work for you? I can help set
> > up a
> > > > > Zoom
> > > > > > > > > > meeting,
> > > > > > > > > > > > > > invite
> > > > > > > > > > > > > > > > > > everyone who
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> might
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> be interested, have it
> > recorded
> > > > and
> > > > > > > shared,
> > > > > > > > > > etc.
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> Thanks,
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> Jun
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> On Tue, Aug 18, 2020 at
> > 11:01 AM
> > > > > Satish
> > > > > > > > > > Duggana <
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> satish. duggana@ gmail. com
> > (
> > > > > satish.
> > > > > > > > > > duggana@
> > > > > > > > > > > > > > gmail. com
> > > > > > > > > > > > > > > > > (
> > > > > > > > > > > > > > > > > > > > > >>>>>>> satish.duggana@gmail.com )
> > ) >
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> wrote:
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> Hi Kowshik,
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> Thanks for looking into the
> > KIP
> > > > and
> > > > > > > sending
> > > > > > > > > > your
> > > > > > > > > > > > > > comments.
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > > >>>>>>> 5001. Under the section
> > "Follower
> > > > > fetch
> > > > > > > > > > protocol
> > > > > > > > > > > > in
> > > > > > > > > > > > > > > > > detail",
> > > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > > > >>>>>>> next-local-offset is the
> > offset
> > > > > upto
> > > > > > > which
> > > > > > > > > > the
> > > > > > > > > > > > > > segments are
> > > > > > > > > > > > > > > > > > copied
> > > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > >
> > > > >
> > > >
> >

Re: [DISCUSS] KIP-405: Kafka Tiered Storage

[Jun Rao <ju...@confluent.io>]

Hi, Satish,

Thanks for the reply. Just a couple of more comments.

9300. Could we add a section on downgrade?

9301. "Feature test cases and test results are documented in this google
spreadsheet
<https://docs.google.com/spreadsheets/d/1XhNJqjzwXvMCcAOhEH0sSXU6RTvyoSf93DHF-YMfGLk/edit?usp=sharing>
." The google spreadsheet doesn't have a link. Could we add the plan for
integration and system systems?

Jun

On Mon, Feb 8, 2021 at 8:21 AM Satish Duggana <sa...@gmail.com>
wrote:

> Hi Manikumar,
> Thanks for your comment. Please find the inline replies below.
>
> 9201. Can we make it clear by mentioning RLM as an internal component and
> RLMM and RSM are pluggable components.
> It's also good to update/add the RLM, RLMM components  diagrams with
> internal components/tasks.
>
> Updated the KIP.
>
> 9202. RLMM metadata topic is a non-compact topic. Can we make clear that
> metadata topic retention time should be greater
>  than user topics. or How about setting retention set to -1 (unlimited) and
> let users to modify it.
>
> I am fine with -1 and updated the configuration doc and made it clear
> in the KIP.
>
> 9203. RLMM has additional responsibility of handling topic delete requests.
> With current design, RLMM implementations need
> to implement deletion logic. How about making RemotePartitionRemover as a
> separate task, which can be reused..
>
> Good point. We had plans to address that in a future KIP, added in
> future work items.
>
> 9204. Can we list all the new error codes added by the KIP?
>
> Those are mentioned in the protocol changes section.
>
> 9205. Can we also support  `remote.log.metadata.producr.*`,
> `remote.log.metadata.consumer.*` prefixed configs to
> override any default configs ?. also include RLMM cache configs, if any.
>
> Good point. Updated the KIP.
>
> 9206. In the Upgrade section, we have below statement
> "Before enabling tiered storage, you should make sure the producer
> snapshots are built for all the segments for that topic
> in all followers. You should wait till the log retention occurs for all the
> segments so that all the segments have producer snapshots."
> Can you add more details about this constraint?
>
> Sure, updated in the KIP.
>
>
> ~Satish.
>
> On Tue, 2 Feb 2021 at 21:04, Manikumar <ma...@gmail.com> wrote:
> >
> > Hi Satish,
> >
> > Thanks for the KIP.  some of my comments below.
> >
> > 9201. Can we make it clear by mentioning RLM as an internal component and
> > RLMM and RSM are pluggable components.
> > It's also good to update/add the RLM, RLMM components  diagrams with
> > internal components/tasks.
> >
> > 9202. RLMM metadata topic is a non-compact topic. Can we make clear that
> > metadata topic retention time should be greater
> >  than user topics. or How about setting retention set to -1 (unlimited)
> and
> > let users to modify it.
> >
> > 9203. RLMM has additional responsibility of handling topic delete
> requests.
> > With current design, RLMM implementations need
> > to implement deletion logic. How about making RemotePartitionRemover as a
> > separate task, which can be reused..
> >
> > 9204. Can we list all the new error codes added by the KIP?
> >
> > 9205. Can we also support  `remote.log.metadata.producr.*`,
> > `remote.log.metadata.consumer.*` prefixed configs to
> > override any default configs ?. also include RLMM cache configs, if any.
> >
> > 9206. In the Upgrade section, we have below statement
> > "Before enabling tiered storage, you should make sure the producer
> > snapshots are built for all the segments for that topic
> > in all followers. You should wait till the log retention occurs for all
> the
> > segments so that all the segments have producer snapshots."
> >
> >  Can you add more details about this constraint?
> >
> >
> > Thanks,
> > Manikumar
> >
> > On Tue, Jan 26, 2021 at 1:12 AM Jun Rao <ju...@confluent.io> wrote:
> >
> > > Hi, Satish,
> > >
> > > Thanks for the reply. A few more comments below.
> > >
> > > 6000. When RSM/RLMM is not available, it seems that we need to return a
> > > retriable error to the affected client requests. So, should we add a
> new
> > > error code for requests like fetch and listOffset?
> > >
> > > 9111. RemotePartitionRemover:
> > > 91111.1 Could we make it clear that it's part of the default RLMM
> > > implementation and a separate implementation is needed if one has a
> > > customized RLMM?
> > > 91111.2 "RPRM gets all the remote log segments for the partition using
> RLMM
> > > and each of these remote log segments is deleted with the next
> steps.RLMM
> > > subscribes to the local remote log metadata partitions and it will
> have the
> > > segment metadata of all the user topic partitions associated with that
> > > remote log metadata partition." It seems that RLMM needs to subscribe
> to
> > > the remote log metadata partitions first before those segments can be
> > > deleted?
> > > 9111.3 There are still references to "remote log cleaners". They need
> to be
> > > replaced with RemotePartitionRemover.
> > >
> > > 9114.1 Could we add the requirement on log.message.format before
> enabling
> > > tiered storage?
> > >
> > > 9116. RemoteLogMetadataFormatter: This is used with the ConsoleConsumer
> > > tool, right? Then, are those new options for ConsoleConsumer and how
> are
> > > they passed in?
> > >
> > > Thanks,
> > >
> > > Jun
> > >
> > >
> > > On Mon, Jan 25, 2021 at 8:02 AM Satish Duggana <
> satish.duggana@gmail.com>
> > > wrote:
> > >
> > > > Hi Jun,
> > > >
> > > > Thanks for your comments. Please find the inline replies below.
> > > > Several of these were discussed/clarified in our last discussion.
> > > >
> > > > 6000. Since we are returning new error codes, we need to bump up the
> > > > protocol version for Fetch request. Also, it will be useful to
> document
> > > all
> > > > new error codes and whether they are retriable or not.
> > > > This previous comment doesn't seem to be addressed.
> > > >
> > > > Updated KIP on fetch protocol and error code.
> > > >
> > > > 9110. flat_file_format: Could you define the serialized
> representation
> > > for
> > > > each field in the header?
> > > >
> > > > Added the serialized representation types in the KIP.
> > > >
> > > > 9111. RPM has the following 2 steps.
> > > > "1. The controller publishes delete_partition_marked event to say
> that
> > > the
> > > > partition is marked for deletion. There can be multiple events
> published
> > > > when the controller restarts or failover and this event will be
> > > > deduplicated by RPM.
> > > > 2. RPM receives the delete_partition_marked and processes it if it
> is not
> > > > yet processed earlier."
> > > > What triggers RPM to read __remote_log_metadata? Is RPM part of the
> > > default
> > > > RLMM implementation or is it meant for any RLMM implementation?
> > > >
> > > > RPM(or RPRM) is only for the default RLMM implementation. RPM
> receives
> > > > the delete_partition_marked events from RLMM and acts on them.
> Updated
> > > > KIP with more details.
> > > >
> > > > 9112. remote.log.manager.task.retry.backoff.ms: It would be useful
> to
> > > make
> > > > it clear in the comment that this is for the initial retry backoff.
> > > >
> > > > Updated the KIP.
> > > >
> > > > 9113. RLMM:
> > > > 9113.1 updateRemoteLogSegmentMetadata(): This comment needs to be
> > > updated.
> > > >
> > > > Updated javadoc of this method.
> > > >
> > > > 9113.2 Should RemoteLogSegmentMetadataUpdate include a leadeEpoch
> field
> > > > since all other update events have leaderEpoch?
> > > >
> > > > +1 to have that,  updated the KIP.
> > > >
> > > > 9113.3 Could we rename RemotePartitionState to
> RemotePartitionDeleteState
> > > > to make it clear this is for deletion?
> > > >
> > > > Sure, updated the KIP.
> > > >
> > > > 9113.4 Could we rename RemoteLogState to RemoteLogSegmentState to
> make it
> > > > clear this is for segment?
> > > >
> > > > Sure, Updated the KIP.
> > > >
> > > > 9114.Upgrade:
> > > > 9114.1 It seems that we require message format > 0.11 for turning on
> the
> > > > remote store feature.
> > > >
> > > > 9114.2 It's not clear to me why remote.log.storage.system.enable
> needs to
> > > > be set to true before bumping up inter.broker.protocol.version.
> > > >
> > > > Agree that based on our discussion, this is not required. Upgrade
> > > > notes is updated.
> > > >
> > > > 9114.3 "If the topic-id is not received in the LeaderAndIsr request
> then
> > > > remote log storage will not start. But it will log an error message
> in
> > > the
> > > > log. One way to address this is to do a rolling restart of that
> broker,
> > > so
> > > > that the leader will be moved to another broker and the controller
> will
> > > > send LeaderAndIsr with the registered topic-id." Why is this needed?
> With
> > > > KIP-516, after upgrading to the latest protocol, topicIds are auto
> > > created.
> > > >
> > > > I thought there may be edge cases of not receiving topic-id but you
> > > > clarified in the meeting that won’t be the case. I agree that it is
> > > > not needed.
> > > >
> > > > 9115. testing: Could you comment on how we plan to do integration and
> > > > system tests? Do we plan to include, for example, an in-memory
> > > > implementation of RSM?
> > > >
> > > > For integration tests, we can have file based RSM that we have. For
> > > > system tests, we can have a single node HDFS cluster in one of the
> > > > containers and use HDFS RSM implementation.
> > > >
> > > > 9116. There is still a todo for the message formatter.
> > > >
> > > > Updated the KIP with the format.
> > > >
> > > >
> > > > Satish.
> > > >
> > > >
> > > > On Tue, 12 Jan 2021 at 07:07, Jun Rao <ju...@confluent.io> wrote:
> > > > >
> > > > > Hi, Satish,
> > > > >
> > > > > Thanks for the reply. A few more followup comments.
> > > > >
> > > > > 6000. Since we are returning new error codes, we need to bump up
> the
> > > > > protocol version for Fetch request. Also, it will be useful to
> document
> > > > all
> > > > > new error codes and whether they are retriable or not.
> > > > > This previous comment doesn't seem to be addressed.
> > > > >
> > > > > 9110. flat_file_format: Could you define the serialized
> representation
> > > > for
> > > > > each field in the header?
> > > > >
> > > > > 9111. RPM has the following 2 steps.
> > > > > "1. The controller publishes delete_partition_marked event to say
> that
> > > > the
> > > > > partition is marked for deletion. There can be multiple events
> > > published
> > > > > when the controller restarts or failover and this event will be
> > > > > deduplicated by RPM.
> > > > > 2. RPM receives the delete_partition_marked and processes it if it
> is
> > > not
> > > > > yet processed earlier."
> > > > > What triggers RPM to read __remote_log_metadata? Is RPM part of the
> > > > default
> > > > > RLMM implementation or is it meant for any RLMM implementation?
> > > > >
> > > > > 9112. remote.log.manager.task.retry.backoff.ms: It would be
> useful to
> > > > make
> > > > > it clear in the comment that this is for the initial retry backoff.
> > > > >
> > > > > 9113. RLMM:
> > > > > 9113.1 updateRemoteLogSegmentMetadata(): This comment needs to be
> > > > updated.
> > > > > 9113.2 Should RemoteLogSegmentMetadataUpdate include a leadeEpoch
> field
> > > > > since all other update events have leaderEpoch?
> > > > > 9113.3 Could we rename RemotePartitionState to
> > > RemotePartitionDeleteState
> > > > > to make it clear this is for deletion?
> > > > > 9113.4 Could we rename RemoteLogState to RemoteLogSegmentState to
> make
> > > it
> > > > > clear this is for segment?
> > > > >
> > > > > 9114.Upgrade:
> > > > > 9114.1 It seems that we require message format > 0.11 for turning
> on
> > > the
> > > > > remote store feature.
> > > > > 9114.2 It's not clear to me why remote.log.storage.system.enable
> needs
> > > to
> > > > > be set to true before bumping up inter.broker.protocol.version.
> > > > > 9114.3 "If the topic-id is not received in the LeaderAndIsr request
> > > then
> > > > > remote log storage will not start. But it will log an error
> message in
> > > > the
> > > > > log. One way to address this is to do a rolling restart of that
> broker,
> > > > so
> > > > > that the leader will be moved to another broker and the controller
> will
> > > > > send LeaderAndIsr with the registered topic-id." Why is this
> needed?
> > > With
> > > > > KIP-516, after upgrading to the latest protocol, topicIds are auto
> > > > created.
> > > > >
> > > > > 9115. testing: Could you comment on how we plan to do integration
> and
> > > > > system tests? Do we plan to include, for example, an in-memory
> > > > > implementation of RSM?
> > > > >
> > > > > 9116. There is still a todo for the message formatter.
> > > > >
> > > > > Jun
> > > > >
> > > > > On Sat, Jan 9, 2021 at 2:04 AM Satish Duggana <
> > > satish.duggana@gmail.com>
> > > > > wrote:
> > > > >
> > > > > > Hi Jun,
> > > > > > Thanks for your comments. Please find the inline replies below.
> > > > > >
> > > > > > 6022. For packages used for server plugins, the convention is to
> > > > > > use org.apache.kafka.server. See java-based Authorizer as an
> example.
> > > > > >
> > > > > > Sure, ‘org.apache.kafka.common.log.remote.storage’ renamed to
> > > > > > ‘org.apache.kafka.server.log.remote.storage’.  Updated in the
> KIP.
> > > > > >
> > > > > > 9100. Do we need DeletePartitionStateRecord in flat_file_format?
> The
> > > > flat
> > > > > > file captures the state of the remote segments. After a
> partition is
> > > > > > deleted, it seems that we just need to remove the partitions's
> remote
> > > > > > segments from the flat file.
> > > > > >
> > > > > > DeletePartitionState might not yet have been processed by RPM
> and not
> > > > > > completed. We  will not have  that in flat  file format  once it
> > > > > > reaches DELETE_PARTITION_FINISHED state.
> > > > > >
> > > > > > 9101. Upgrade: It will be useful to allow direct upgrade from an
> old
> > > > > > version. It seems that's doable. One can just do the normal
> upgrade
> > > > first
> > > > > > and wait enough time (for producer snapshots to be built), and
> then
> > > > enable
> > > > > > remote storage.
> > > > > >
> > > > > > Upgrade notes updates in the KIP.
> > > > > >
> > > > > > 9102. RemotePartitionRemover(RPM) process: Is it true that RPM
> starts
> > > > > > tracking the remote segments when
> RLMM.onPartitionLeadershipChanges()
> > > > is
> > > > > > called with the broker being the leader for __remote_log_metadata
> > > > > > partition? If so, could we document it?
> > > > > >
> > > > > > The current plan is to have that as part of RLMM and RPM uses
> that to
> > > > > > get the remote segments list. I will add this detail in the
> > > respective
> > > > > > sections.
> > > > > >
> > > > > > Satish.
> > > > > >
> > > > > > On Wed, 16 Dec 2020 at 23:55, Jun Rao <ju...@confluent.io> wrote:
> > > > > > >
> > > > > > > Hi, Satish,
> > > > > > >
> > > > > > > Thanks for the reply. A few more followup comments.
> > > > > > >
> > > > > > > 6022. For packages used for server plugins, the convention is
> to
> > > > > > > use org.apache.kafka.server. See java-based Authorizer as an
> > > example.
> > > > > > >
> > > > > > > 9100. Do we need DeletePartitionStateRecord in
> flat_file_format?
> > > The
> > > > flat
> > > > > > > file captures the state of the remote segments. After a
> partition
> > > is
> > > > > > > deleted, it seems that we just need to remove the partitions's
> > > remote
> > > > > > > segments from the flat file.
> > > > > > >
> > > > > > > 9101. Upgrade: It will be useful to allow direct upgrade from
> an
> > > old
> > > > > > > version. It seems that's doable. One can just do the normal
> upgrade
> > > > first
> > > > > > > and wait enough time (for producer snapshots to be built), and
> then
> > > > > > enable
> > > > > > > remote storage.
> > > > > > >
> > > > > > > 9102. RemotePartitionRemover(RPM) process: Is it true that RPM
> > > starts
> > > > > > > tracking the remote segments when
> > > > RLMM.onPartitionLeadershipChanges() is
> > > > > > > called with the broker being the leader for
> __remote_log_metadata
> > > > > > > partition? If so, could we document it?
> > > > > > >
> > > > > > > Jun
> > > > > > >
> > > > > > > On Tue, Dec 15, 2020 at 8:47 AM Kowshik Prakasam <
> > > > kprakasam@confluent.io
> > > > > > >
> > > > > > > wrote:
> > > > > > >
> > > > > > > > Hi Satish,
> > > > > > > >
> > > > > > > > Thanks for the updates! A few more comments below.
> > > > > > > >
> > > > > > > > 9001. Under the "Upgrade" section, there is a line
> mentioning:
> > > > > > "Upgrade the
> > > > > > > > existing Kafka cluster to 2.7 version and allow this to run
> for
> > > > the log
> > > > > > > > retention of user topics that you want to enable tiered
> storage.
> > > > This
> > > > > > will
> > > > > > > > allow all the topics to have the producer snapshots
> generated for
> > > > each
> > > > > > log
> > > > > > > > segment." -- Which associated change in AK were you
> referring to
> > > > here?
> > > > > > Is
> > > > > > > > it: https://github.com/apache/kafka/pull/7929 ? It seems
> like I
> > > > don't
> > > > > > see
> > > > > > > > it in the 2.7 release branch yet, here is the link:
> > > > > > > > https://github.com/apache/kafka/commits/2.7.
> > > > > > > >
> > > > > > > > 9002. Under the "Upgrade" section, the configuration
> mentioned is
> > > > > > > > 'remote.log.storage.system.enable'. However, under "Public
> > > > Interfaces"
> > > > > > > > section the corresponding configuration is
> > > > > > 'remote.storage.system.enable'.
> > > > > > > > Could we use the same one in both, maybe
> > > > > > > > 'remote.log.storage.system.enable'?
> > > > > > > >
> > > > > > > > 9003. Under "Per Topic Configuration", the KIP recommends
> setting
> > > > > > > > 'remote.log.storage.enable' to true at a per-topic level. It
> will
> > > > be
> > > > > > useful
> > > > > > > > to add a line that if the user wants to enable it for all
> topics,
> > > > then
> > > > > > they
> > > > > > > > should be able to set the cluster-wide default to true.
> Also, it
> > > > will
> > > > > > be
> > > > > > > > useful to mention that the KIP currently does not support
> setting
> > > > it to
> > > > > > > > false (after it is set to true), and add that to the future
> work
> > > > > > section.
> > > > > > > >
> > > > > > > > 9004. Under "Committed offsets file format", the sample
> provided
> > > > shows
> > > > > > > > partition number and offset. Is the topic name required for
> > > > identifying
> > > > > > > > which topic the partitions belong to?
> > > > > > > >
> > > > > > > > 9005. Under "Internal flat-file store format of remote log
> > > > metadata",
> > > > > > it
> > > > > > > > seems useful to specify both topic name and topic ID for
> > > debugging
> > > > > > > > purposes.
> > > > > > > >
> > > > > > > > 9006. Under "Internal flat-file store format of remote log
> > > > metadata",
> > > > > > the
> > > > > > > > description of "metadata-topic-offset" currently says
> "offset of
> > > > the
> > > > > > remote
> > > > > > > > log metadata topic from which this topic partition's remote
> log
> > > > > > metadata is
> > > > > > > > fetched." Just for the wording, perhaps you meant to refer
> to the
> > > > > > offset
> > > > > > > > upto which the file has been committed? i.e. "offset of the
> > > remote
> > > > log
> > > > > > > > metadata topic upto which this topic partition's remote log
> > > > metadata
> > > > > > has
> > > > > > > > been committed into this file."
> > > > > > > >
> > > > > > > > 9007. Under "Internal flat-file store format of remote log
> > > > metadata",
> > > > > > the
> > > > > > > > schema of the payload (i.e. beyond the header) seems to
> contain
> > > the
> > > > > > events
> > > > > > > > from the metadata topic. It seems useful to instead persist
> the
> > > > > > > > representation of the materialized state of the events, so
> that
> > > > for the
> > > > > > > > same segment only the latest state is stored. Besides
> reducing
> > > > storage
> > > > > > > > footprint, this also is likely to relate directly with the
> > > > in-memory
> > > > > > > > representation of the RLMM cache (which probably is some
> kind of
> > > a
> > > > Map
> > > > > > with
> > > > > > > > key being segment ID and value being the segment state), so
> > > > recovery
> > > > > > from
> > > > > > > > disk will be straightforward.
> > > > > > > >
> > > > > > > > 9008. Under "Topic deletion lifecycle", step (1), it will be
> > > > useful to
> > > > > > > > mention when in the deletion flow does the controller
> publish the
> > > > > > > > delete_partition_marked event to say that the partition is
> marked
> > > > for
> > > > > > > > deletion?
> > > > > > > >
> > > > > > > > 9009. There are ~4 TODOs in the KIP. Could you please address
> > > > these or
> > > > > > > > remove them?
> > > > > > > >
> > > > > > > > 9010. There is a reference to a Google doc on the KIP which
> was
> > > > used
> > > > > > > > earlier for discussions. Please could you remove the
> reference,
> > > > since
> > > > > > the
> > > > > > > > KIP is the source of the truth?
> > > > > > > >
> > > > > > > > 9011. This feedback is from an earlier comment. In the
> > > > > > RemoteStorageManager
> > > > > > > > interface, there is an API defined for each file type. For
> > > example,
> > > > > > > > fetchOffsetIndex, fetchTimestampIndex etc. To avoid the
> > > > duplication,
> > > > > > I'd
> > > > > > > > suggest we can instead have a FileType enum and a common get
> API
> > > > based
> > > > > > on
> > > > > > > > the FileType. What do you think?
> > > > > > > >
> > > > > > > >
> > > > > > > > Cheers,
> > > > > > > > Kowshik
> > > > > > > >
> > > > > > > >
> > > > > > > > On Mon, Dec 14, 2020 at 11:07 AM Satish Duggana <
> > > > > > satish.duggana@gmail.com>
> > > > > > > > wrote:
> > > > > > > >
> > > > > > > > > Hi Jun,
> > > > > > > > > Thanks for your comments. Please go through the inline
> replies.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > 5102.2: It seems that both positions can just be int.
> Another
> > > > option
> > > > > > is
> > > > > > > > to
> > > > > > > > > have two methods. Would it be clearer?
> > > > > > > > >
> > > > > > > > >     InputStream
> fetchLogSegmentData(RemoteLogSegmentMetadata
> > > > > > > > > remoteLogSegmentMetadata,  int startPosition)
> > > > > > > > throwsRemoteStorageException;
> > > > > > > > >
> > > > > > > > >     InputStream
> fetchLogSegmentData(RemoteLogSegmentMetadata
> > > > > > > > > remoteLogSegmentMetadata, int startPosition, int
> endPosition)
> > > > throws
> > > > > > > > > RemoteStorageException;
> > > > > > > > >
> > > > > > > > > That makes sense to me, updated the KIP.
> > > > > > > > >
> > > > > > > > > 6003: Could you also update the javadoc for the return
> value?
> > > > > > > > >
> > > > > > > > > Updated.
> > > > > > > > >
> > > > > > > > > 6020: local.log.retention.bytes: Should it default to
> > > > > > log.retention.bytes
> > > > > > > > > to be consistent with local.log.retention.ms?
> > > > > > > > >
> > > > > > > > > Yes, it can be defaulted to log.retention.bytes.
> > > > > > > > >
> > > > > > > > > 6021: Could you define TopicIdPartition?
> > > > > > > > >
> > > > > > > > > Added TopicIdPartition in the KIP.
> > > > > > > > >
> > > > > > > > > 6022: For all public facing classes, could you specify the
> > > > package
> > > > > > name?
> > > > > > > > >
> > > > > > > > > Updated.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > Thanks,
> > > > > > > > > Satish.
> > > > > > > > >
> > > > > > > > > On Tue, Dec 8, 2020 at 12:59 AM Jun Rao <ju...@confluent.io>
> > > > wrote:
> > > > > > > > > >
> > > > > > > > > > Hi, Satish,
> > > > > > > > > >
> > > > > > > > > > Thanks for the reply. A few more comments below.
> > > > > > > > > >
> > > > > > > > > > 5102.2: It seems that both positions can just be int.
> Another
> > > > > > option is
> > > > > > > > > to
> > > > > > > > > > have two methods. Would it be clearer?
> > > > > > > > > >
> > > > > > > > > >     InputStream
> fetchLogSegmentData(RemoteLogSegmentMetadata
> > > > > > > > > > remoteLogSegmentMetadata,
> > > > > > > > > >                                     int startPosition)
> throws
> > > > > > > > > > RemoteStorageException;
> > > > > > > > > >
> > > > > > > > > >     InputStream
> fetchLogSegmentData(RemoteLogSegmentMetadata
> > > > > > > > > > remoteLogSegmentMetadata,
> > > > > > > > > >                                     int startPosition,
> int
> > > > > > endPosition)
> > > > > > > > > > throws RemoteStorageException;
> > > > > > > > > >
> > > > > > > > > > 6003: Could you also update the javadoc for the return
> value?
> > > > > > > > > >
> > > > > > > > > > 6010: What kind of tiering throughput have you seen with
> 5
> > > > threads?
> > > > > > > > > >
> > > > > > > > > > 6020: local.log.retention.bytes: Should it default to
> > > > > > > > log.retention.bytes
> > > > > > > > > > to be consistent with local.log.retention.ms?
> > > > > > > > > >
> > > > > > > > > > 6021: Could you define TopicIdPartition?
> > > > > > > > > >
> > > > > > > > > > 6022: For all public facing classes, could you specify
> the
> > > > package
> > > > > > > > name?
> > > > > > > > > >
> > > > > > > > > > It seems that you already added the topicId support. Two
> > > other
> > > > > > > > remaining
> > > > > > > > > > items are (a) the format of local tier metadata storage
> and
> > > (b)
> > > > > > > > upgrade.
> > > > > > > > > >
> > > > > > > > > > Jun
> > > > > > > > > >
> > > > > > > > > > On Mon, Dec 7, 2020 at 8:56 AM Satish Duggana <
> > > > > > > > satish.duggana@gmail.com>
> > > > > > > > > > wrote:
> > > > > > > > > >
> > > > > > > > > > > Hi Jun,
> > > > > > > > > > > Thanks for your comments. Please find the inline
> replies
> > > > below.
> > > > > > > > > > >
> > > > > > > > > > > >605.2 It's rare for the follower to need the remote
> data.
> > > > So,
> > > > > > the
> > > > > > > > > current
> > > > > > > > > > > approach is fine too. Could you document the process of
> > > > > > rebuilding
> > > > > > > > the
> > > > > > > > > > > producer state since we can't simply trim the
> producerState
> > > > to an
> > > > > > > > > offset in
> > > > > > > > > > > the middle of a segment.
> > > > > > > > > > >
> > > > > > > > > > > Will clarify in the KIP.
> > > > > > > > > > >
> > > > > > > > > > > >5102.2 Would it be clearer to make startPosiont long
> and
> > > > > > endPosition
> > > > > > > > > of
> > > > > > > > > > > Optional<Long>?
> > > > > > > > > > >
> > > > > > > > > > > We will have arg checks with respective validation. It
> is
> > > > not a
> > > > > > good
> > > > > > > > > > > practice to have arguments with optional as mentioned
> here.
> > > > > > > > > > > https://rules.sonarsource.com/java/RSPEC-3553
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > >5102.5 LogSegmentData still has leaderEpochIndex as
> File
> > > > > > instead of
> > > > > > > > > > > ByteBuffer.
> > > > > > > > > > >
> > > > > > > > > > > Updated.
> > > > > > > > > > >
> > > > > > > > > > > >5102.7 Could you define all public methods for
> > > > LogSegmentData?
> > > > > > > > > > >
> > > > > > > > > > > Updated.
> > > > > > > > > > >
> > > > > > > > > > > >5103.5 Could you change the reference to
> > > > > > rlm_process_interval_ms and
> > > > > > > > > > > rlm_retry_interval_ms to the new config names? Also,
> the
> > > > retry
> > > > > > > > interval
> > > > > > > > > > > config seems still missing. It would be useful to
> support
> > > > > > exponential
> > > > > > > > > > > backoff with the retry interval config.
> > > > > > > > > > >
> > > > > > > > > > > Good point. We wanted the retry with truncated
> exponential
> > > > > > backoff,
> > > > > > > > > > > updated the KIP.
> > > > > > > > > > >
> > > > > > > > > > > >5111. "RLM follower fetches the earliest offset for
> the
> > > > earliest
> > > > > > > > > leader
> > > > > > > > > > > epoch by calling RLMM.earliestLogOffset(TopicPartition
> > > > > > > > topicPartition,
> > > > > > > > > int
> > > > > > > > > > > leaderEpoch) and updates that as the log start offset."
> > > This
> > > > > > text is
> > > > > > > > > still
> > > > > > > > > > > there. Also, could we remove earliestLogOffset() from
> RLMM?
> > > > > > > > > > >
> > > > > > > > > > > Updated.
> > > > > > > > > > >
> > > > > > > > > > > >5115. There are still references to "remote log
> cleaners".
> > > > > > > > > > >
> > > > > > > > > > > Updated.
> > > > > > > > > > >
> > > > > > > > > > > >6000. Since we are returning new error codes, we need
> to
> > > > bump
> > > > > > up the
> > > > > > > > > > > protocol version for Fetch request. Also, it will be
> useful
> > > > to
> > > > > > > > > document all
> > > > > > > > > > > new error codes and whether they are retriable or not.
> > > > > > > > > > >
> > > > > > > > > > > Sure, we will add that in the KIP.
> > > > > > > > > > >
> > > > > > > > > > > >6001. public Map<Long, Long> segmentLeaderEpochs():
> > > > Currently,
> > > > > > > > > leaderEpoch
> > > > > > > > > > > is int32 instead of long.
> > > > > > > > > > >
> > > > > > > > > > > Updated.
> > > > > > > > > > >
> > > > > > > > > > > >6002. Is RemoteLogSegmentMetadata.markedForDeletion()
> > > needed
> > > > > > given
> > > > > > > > > > > RemoteLogSegmentMetadata.state()?
> > > > > > > > > > >
> > > > > > > > > > > No, it is fixed.
> > > > > > > > > > >
> > > > > > > > > > > >6003. RemoteLogSegmentMetadata
> > > > > > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > > > topicPartition, long offset, int epochForOffset):
> Should
> > > this
> > > > > > return
> > > > > > > > > > > Optional<RemoteLogSegmentMetadata>?
> > > > > > > > > > >
> > > > > > > > > > > That makes sense, updated.
> > > > > > > > > > >
> > > > > > > > > > > >6005. RemoteLogState: It seems it's better to split it
> > > > between
> > > > > > > > > > > DeletePartitionUpdate and
> RemoteLogSegmentMetadataUpdate
> > > > since
> > > > > > the
> > > > > > > > > states
> > > > > > > > > > > are never shared between the two use cases.
> > > > > > > > > > >
> > > > > > > > > > > Agree with that, updated.
> > > > > > > > > > >
> > > > > > > > > > > >6006. RLMM.onPartitionLeadershipChanges(): This may
> be ok.
> > > > > > However,
> > > > > > > > > is it
> > > > > > > > > > > ture that other than the metadata topic, RLMM just
> needs to
> > > > know
> > > > > > > > > whether
> > > > > > > > > > > there is a replica assigned to this broker and doesn't
> need
> > > > to
> > > > > > know
> > > > > > > > > whether
> > > > > > > > > > > the replica is the leader or the follower?
> > > > > > > > > > >
> > > > > > > > > > > That may be true. If the implementation does not need
> that,
> > > > it
> > > > > > can
> > > > > > > > > > > ignore the information in the callback.
> > > > > > > > > > >
> > > > > > > > > > > >6007: "Handle expired remote segments (leader and
> > > > follower)":
> > > > > > Why is
> > > > > > > > > this
> > > > > > > > > > > needed in both the leader and the follower?
> > > > > > > > > > >
> > > > > > > > > > > Updated.
> > > > > > > > > > >
> > > > > > > > > > > >6008.       "name": "SegmentSizeInBytes",
> > > > > > > > > > >                 "type": "int64",
> > > > > > > > > > > The segment size can just be int32.
> > > > > > > > > > >
> > > > > > > > > > > Updated.
> > > > > > > > > > >
> > > > > > > > > > > >6009. For the record format in the log, it seems that
> we
> > > > need
> > > > > > to add
> > > > > > > > > > > record
> > > > > > > > > > > type and record version before the serialized bytes.
> We can
> > > > > > follow
> > > > > > > > the
> > > > > > > > > > > convention used in
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > >
> > > >
> > >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-631%3A+The+Quorum-based+Kafka+Controller#KIP631:TheQuorumbasedKafkaController-RecordFormats
> > > > > > > > > > >
> > > > > > > > > > > Yes, KIP already mentions that these are serialized
> before
> > > > the
> > > > > > > > payload
> > > > > > > > > > > as below. We will mention explicitly that these two are
> > > > written
> > > > > > > > before
> > > > > > > > > > > the data is written.
> > > > > > > > > > >
> > > > > > > > > > > RLMM instance on broker publishes the message to the
> topic
> > > > with
> > > > > > key
> > > > > > > > as
> > > > > > > > > > > null and value with the below format.
> > > > > > > > > > >
> > > > > > > > > > > type      : unsigned var int, represents the value
> type.
> > > This
> > > > > > value
> > > > > > > > is
> > > > > > > > > > > 'apikey' as mentioned in the schema.
> > > > > > > > > > > version : unsigned var int, the 'version' number of the
> > > type
> > > > as
> > > > > > > > > > > mentioned in the schema.
> > > > > > > > > > > data      : record payload in kafka protocol message
> > > format.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > >6010. remote.log.manager.thread.pool.size: The default
> > > > value is
> > > > > > 10.
> > > > > > > > > This
> > > > > > > > > > > might be too high when enabling the tiered feature for
> the
> > > > first
> > > > > > > > time.
> > > > > > > > > > > Since there are lots of segments that need to be tiered
> > > > > > initially, a
> > > > > > > > > large
> > > > > > > > > > > number of threads could overwhelm the broker.
> > > > > > > > > > >
> > > > > > > > > > > Is the default value 5 reasonable?
> > > > > > > > > > >
> > > > > > > > > > > 6011. "The number of milli seconds to keep the local
> log
> > > > segment
> > > > > > > > > before it
> > > > > > > > > > > gets deleted. If not set, the value in
> > > > `log.retention.minutes` is
> > > > > > > > > used. If
> > > > > > > > > > > set to -1, no time limit is applied." We should use
> > > > > > log.retention.ms
> > > > > > > > > > > instead of log.retention.minutes.
> > > > > > > > > > > Nice typo catch. Updated the KIP.
> > > > > > > > > > >
> > > > > > > > > > > Thanks,
> > > > > > > > > > > Satish.
> > > > > > > > > > >
> > > > > > > > > > > On Thu, Dec 3, 2020 at 8:03 AM Jun Rao <
> jun@confluent.io>
> > > > wrote:
> > > > > > > > > > > >
> > > > > > > > > > > > Hi, Satish,
> > > > > > > > > > > >
> > > > > > > > > > > > Thanks for the updated KIP. A few more comments
> below.
> > > > > > > > > > > >
> > > > > > > > > > > > 605.2 It's rare for the follower to need the remote
> data.
> > > > So,
> > > > > > the
> > > > > > > > > current
> > > > > > > > > > > > approach is fine too. Could you document the process
> of
> > > > > > rebuilding
> > > > > > > > > the
> > > > > > > > > > > > producer state since we can't simply trim the
> > > > producerState to
> > > > > > an
> > > > > > > > > offset
> > > > > > > > > > > in
> > > > > > > > > > > > the middle of a segment.
> > > > > > > > > > > >
> > > > > > > > > > > > 5102.2 Would it be clearer to make startPosiont long
> and
> > > > > > > > endPosition
> > > > > > > > > of
> > > > > > > > > > > > Optional<Long>?
> > > > > > > > > > > >
> > > > > > > > > > > > 5102.5 LogSegmentData still has leaderEpochIndex as
> File
> > > > > > instead of
> > > > > > > > > > > > ByteBuffer.
> > > > > > > > > > > >
> > > > > > > > > > > > 5102.7 Could you define all public methods for
> > > > LogSegmentData?
> > > > > > > > > > > >
> > > > > > > > > > > > 5103.5 Could you change the reference to
> > > > > > rlm_process_interval_ms
> > > > > > > > and
> > > > > > > > > > > > rlm_retry_interval_ms to the new config names? Also,
> the
> > > > retry
> > > > > > > > > interval
> > > > > > > > > > > > config seems still missing. It would be useful to
> support
> > > > > > > > exponential
> > > > > > > > > > > > backoff with the retry interval config.
> > > > > > > > > > > >
> > > > > > > > > > > > 5111. "RLM follower fetches the earliest offset for
> the
> > > > > > earliest
> > > > > > > > > leader
> > > > > > > > > > > > epoch by calling
> RLMM.earliestLogOffset(TopicPartition
> > > > > > > > > topicPartition,
> > > > > > > > > > > int
> > > > > > > > > > > > leaderEpoch) and updates that as the log start
> offset."
> > > > This
> > > > > > text
> > > > > > > > is
> > > > > > > > > > > still
> > > > > > > > > > > > there. Also, could we remove earliestLogOffset() from
> > > RLMM?
> > > > > > > > > > > >
> > > > > > > > > > > > 5115. There are still references to "remote log
> > > cleaners".
> > > > > > > > > > > >
> > > > > > > > > > > > 6000. Since we are returning new error codes, we
> need to
> > > > bump
> > > > > > up
> > > > > > > > the
> > > > > > > > > > > > protocol version for Fetch request. Also, it will be
> > > > useful to
> > > > > > > > > document
> > > > > > > > > > > all
> > > > > > > > > > > > new error codes and whether they are retriable or
> not.
> > > > > > > > > > > >
> > > > > > > > > > > > 6001. public Map<Long, Long> segmentLeaderEpochs():
> > > > Currently,
> > > > > > > > > > > leaderEpoch
> > > > > > > > > > > > is int32 instead of long.
> > > > > > > > > > > >
> > > > > > > > > > > > 6002. Is RemoteLogSegmentMetadata.markedForDeletion()
> > > > needed
> > > > > > given
> > > > > > > > > > > > RemoteLogSegmentMetadata.state()?
> > > > > > > > > > > >
> > > > > > > > > > > > 6003. RemoteLogSegmentMetadata
> > > > > > > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > > > > topicPartition, long offset, int epochForOffset):
> Should
> > > > this
> > > > > > > > return
> > > > > > > > > > > > Optional<RemoteLogSegmentMetadata>?
> > > > > > > > > > > >
> > > > > > > > > > > > 6004. DeletePartitionUpdate.epoch(): It would be
> useful
> > > to
> > > > > > pick a
> > > > > > > > > more
> > > > > > > > > > > > indicative name so that people understand what epoch
> this
> > > > is.
> > > > > > > > > > > >
> > > > > > > > > > > > 6005. RemoteLogState: It seems it's better to split
> it
> > > > between
> > > > > > > > > > > > DeletePartitionUpdate and
> RemoteLogSegmentMetadataUpdate
> > > > since
> > > > > > the
> > > > > > > > > states
> > > > > > > > > > > > are never shared between the two use cases.
> > > > > > > > > > > >
> > > > > > > > > > > > 6006. RLMM.onPartitionLeadershipChanges(): This may
> be
> > > ok.
> > > > > > However,
> > > > > > > > > is it
> > > > > > > > > > > > ture that other than the metadata topic, RLMM just
> needs
> > > to
> > > > > > know
> > > > > > > > > whether
> > > > > > > > > > > > there is a replica assigned to this broker and
> doesn't
> > > > need to
> > > > > > know
> > > > > > > > > > > whether
> > > > > > > > > > > > the replica is the leader or the follower?
> > > > > > > > > > > >
> > > > > > > > > > > > 6007: "Handle expired remote segments (leader and
> > > > follower)":
> > > > > > Why
> > > > > > > > is
> > > > > > > > > this
> > > > > > > > > > > > needed in both the leader and the follower?
> > > > > > > > > > > >
> > > > > > > > > > > > 6008.       "name": "SegmentSizeInBytes",
> > > > > > > > > > > >                 "type": "int64",
> > > > > > > > > > > > The segment size can just be int32.
> > > > > > > > > > > >
> > > > > > > > > > > > 6009. For the record format in the log, it seems
> that we
> > > > need
> > > > > > to
> > > > > > > > add
> > > > > > > > > > > record
> > > > > > > > > > > > type and record version before the serialized bytes.
> We
> > > can
> > > > > > follow
> > > > > > > > > the
> > > > > > > > > > > > convention used in
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > >
> > > >
> > >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-631%3A+The+Quorum-based+Kafka+Controller#KIP631:TheQuorumbasedKafkaController-RecordFormats
> > > > > > > > > > > > .
> > > > > > > > > > > >
> > > > > > > > > > > > 6010. remote.log.manager.thread.pool.size: The
> default
> > > > value
> > > > > > is 10.
> > > > > > > > > This
> > > > > > > > > > > > might be too high when enabling the tiered feature
> for
> > > the
> > > > > > first
> > > > > > > > > time.
> > > > > > > > > > > > Since there are lots of segments that need to be
> tiered
> > > > > > initially,
> > > > > > > > a
> > > > > > > > > > > large
> > > > > > > > > > > > number of threads could overwhelm the broker.
> > > > > > > > > > > >
> > > > > > > > > > > > 6011. "The number of milli seconds to keep the local
> log
> > > > > > segment
> > > > > > > > > before
> > > > > > > > > > > it
> > > > > > > > > > > > gets deleted. If not set, the value in
> > > > `log.retention.minutes`
> > > > > > is
> > > > > > > > > used.
> > > > > > > > > > > If
> > > > > > > > > > > > set to -1, no time limit is applied." We should use
> > > > > > > > log.retention.ms
> > > > > > > > > > > > instead of log.retention.minutes.
> > > > > > > > > > > >
> > > > > > > > > > > > Jun
> > > > > > > > > > > >
> > > > > > > > > > > > On Tue, Dec 1, 2020 at 2:42 AM Satish Duggana <
> > > > > > > > > satish.duggana@gmail.com>
> > > > > > > > > > > > wrote:
> > > > > > > > > > > >
> > > > > > > > > > > > > Hi,
> > > > > > > > > > > > > We updated the KIP with the points mentioned in the
> > > > earlier
> > > > > > mail
> > > > > > > > > > > > > except for KIP-516 related changes. You can go
> through
> > > > them
> > > > > > and
> > > > > > > > > let us
> > > > > > > > > > > > > know if you have any comments. We will update the
> KIP
> > > > with
> > > > > > the
> > > > > > > > > > > > > remaining todo items and KIP-516 related changes
> by end
> > > > of
> > > > > > this
> > > > > > > > > > > > > week(5th Dec).
> > > > > > > > > > > > >
> > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > Satish.
> > > > > > > > > > > > >
> > > > > > > > > > > > > On Tue, Nov 10, 2020 at 8:26 PM Satish Duggana <
> > > > > > > > > > > satish.duggana@gmail.com>
> > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Hi Jun,
> > > > > > > > > > > > > > Thanks for your comments. Please find the inline
> > > > replies
> > > > > > below.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 605.2 "Build the local leader epoch cache by
> cutting
> > > > the
> > > > > > leader
> > > > > > > > > epoch
> > > > > > > > > > > > > > sequence received from remote storage to [LSO,
> > > ELO]." I
> > > > > > > > > mentioned an
> > > > > > > > > > > > > issue
> > > > > > > > > > > > > > earlier. Suppose the leader's local start offset
> is
> > > > 100.
> > > > > > The
> > > > > > > > > follower
> > > > > > > > > > > > > finds
> > > > > > > > > > > > > > a remote segment covering offset range [80,
> 120). The
> > > > > > > > > producerState
> > > > > > > > > > > with
> > > > > > > > > > > > > > this remote segment is up to offset 120. To trim
> the
> > > > > > > > > producerState to
> > > > > > > > > > > > > > offset 100 requires more work since one needs to
> > > > download
> > > > > > the
> > > > > > > > > > > previous
> > > > > > > > > > > > > > producerState up to offset 80 and then replay the
> > > > messages
> > > > > > from
> > > > > > > > > 80 to
> > > > > > > > > > > > > 100.
> > > > > > > > > > > > > > It seems that it's simpler in this case for the
> > > > follower
> > > > > > just
> > > > > > > > to
> > > > > > > > > > > take the
> > > > > > > > > > > > > > remote segment as it is and start fetching from
> > > offset
> > > > 120.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > We chose that approach to avoid any edge cases
> here.
> > > It
> > > > > > may be
> > > > > > > > > > > > > > possible that the remote log segment that is
> received
> > > > may
> > > > > > not
> > > > > > > > > have
> > > > > > > > > > > the
> > > > > > > > > > > > > > same leader epoch sequence from 100-120 as it
> > > contains
> > > > on
> > > > > > the
> > > > > > > > > > > > > > leader(this can happen due to unclean leader).
> It is
> > > > safe
> > > > > > to
> > > > > > > > > start
> > > > > > > > > > > > > > from what the leader returns here.Another way is
> to
> > > > find
> > > > > > the
> > > > > > > > > remote
> > > > > > > > > > > > > > log segment
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5016. Just to echo what Kowshik was saying. It
> seems
> > > > that
> > > > > > > > > > > > > > RLMM.onPartitionLeadershipChanges() is only
> called on
> > > > the
> > > > > > > > > replicas
> > > > > > > > > > > for a
> > > > > > > > > > > > > > partition, not on the replicas for the
> > > > > > > > > __remote_log_segment_metadata
> > > > > > > > > > > > > > partition. It's not clear how the leader of
> > > > > > > > > > > __remote_log_segment_metadata
> > > > > > > > > > > > > > obtains the metadata for remote segments for
> > > deletion.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > RLMM will always receive the callback for the
> remote
> > > > log
> > > > > > > > metadata
> > > > > > > > > > > > > > topic partitions hosted on the local broker and
> these
> > > > will
> > > > > > be
> > > > > > > > > > > > > > subscribed. I will make this clear in the KIP.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5100. KIP-516 has been accepted and is being
> > > > implemented
> > > > > > now.
> > > > > > > > > Could
> > > > > > > > > > > you
> > > > > > > > > > > > > > update the KIP based on topicID?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > We mentioned KIP-516 and how it helps. We will
> update
> > > > this
> > > > > > KIP
> > > > > > > > > with
> > > > > > > > > > > > > > all the changes it brings with KIP-516.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5101. RLMM: It would be useful to clarify how the
> > > > > > following two
> > > > > > > > > APIs
> > > > > > > > > > > are
> > > > > > > > > > > > > > used. According to the wiki, the former is used
> for
> > > > topic
> > > > > > > > > deletion
> > > > > > > > > > > and
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > latter is used for retention. It seems that
> retention
> > > > > > should
> > > > > > > > use
> > > > > > > > > the
> > > > > > > > > > > > > former
> > > > > > > > > > > > > > since remote segments without a matching epoch
> in the
> > > > > > leader
> > > > > > > > > > > (potentially
> > > > > > > > > > > > > > due to unclean leader election) also need to be
> > > garbage
> > > > > > > > > collected.
> > > > > > > > > > > The
> > > > > > > > > > > > > > latter seems to be used for the new leader to
> > > > determine the
> > > > > > > > last
> > > > > > > > > > > tiered
> > > > > > > > > > > > > > segment.
> > > > > > > > > > > > > >     default Iterator<RemoteLogSegmentMetadata>
> > > > > > > > > > > > > > listRemoteLogSegments(TopicPartition
> topicPartition)
> > > > > > > > > > > > > >     Iterator<RemoteLogSegmentMetadata>
> > > > > > > > > > > > > listRemoteLogSegments(TopicPartition
> > > > > > > > > > > > > > topicPartition, long leaderEpoch);
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Right,.that is what we are currently doing. We
> will
> > > > update
> > > > > > the
> > > > > > > > > > > > > > javadocs and wiki with that. Earlier, we did not
> want
> > > > to
> > > > > > remove
> > > > > > > > > the
> > > > > > > > > > > > > > segments which are not matched with leader epochs
> > > from
> > > > the
> > > > > > > > ladder
> > > > > > > > > > > > > > partition as they may be used later by a replica
> > > which
> > > > can
> > > > > > > > > become a
> > > > > > > > > > > > > > leader (unclean leader election) and refer those
> > > > segments.
> > > > > > But
> > > > > > > > > that
> > > > > > > > > > > > > > may leak these segments in remote storage until
> the
> > > > topic
> > > > > > > > > lifetime.
> > > > > > > > > > > We
> > > > > > > > > > > > > > decided to cleanup the segments with the oldest
> > > incase
> > > > of
> > > > > > size
> > > > > > > > > based
> > > > > > > > > > > > > > retention also.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5102. RSM:
> > > > > > > > > > > > > > 5102.1 For methods like fetchLogSegmentData(), it
> > > seems
> > > > > > that
> > > > > > > > > they can
> > > > > > > > > > > > > > use RemoteLogSegmentId instead of
> > > > RemoteLogSegmentMetadata.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > It will be useful to have metadata for RSM to
> fetch
> > > log
> > > > > > > > segment.
> > > > > > > > > It
> > > > > > > > > > > > > > may create location/path using id with other
> metadata
> > > > too.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5102.2 In fetchLogSegmentData(), should we use
> long
> > > > > > instead of
> > > > > > > > > Long?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Wanted to keep endPosition as optional to read
> till
> > > the
> > > > > > end of
> > > > > > > > > the
> > > > > > > > > > > > > > segment and avoid sentinels.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5102.3 Why only some of the methods have default
> > > > > > implementation
> > > > > > > > > and
> > > > > > > > > > > > > others
> > > > > > > > > > > > > > Don't?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Actually,  RSM will not have any default
> > > > implementations.
> > > > > > > > Those 3
> > > > > > > > > > > > > > methods were made default earlier for tests etc.
> > > > Updated
> > > > > > the
> > > > > > > > > wiki.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5102.4. Could we define
> > > RemoteLogSegmentMetadataUpdate
> > > > > > > > > > > > > > and DeletePartitionUpdate?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Sure, they will be added.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5102.5 LogSegmentData: It seems that it's easier
> to
> > > > pass
> > > > > > > > > > > > > > in leaderEpochIndex as a ByteBuffer or byte array
> > > than
> > > > a
> > > > > > file
> > > > > > > > > since
> > > > > > > > > > > it
> > > > > > > > > > > > > will
> > > > > > > > > > > > > > be generated in memory.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Right, this is in plan.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5102.6 RemoteLogSegmentMetadata: It seems that it
> > > needs
> > > > > > both
> > > > > > > > > > > baseOffset
> > > > > > > > > > > > > and
> > > > > > > > > > > > > > startOffset. For example, deleteRecords() could
> move
> > > > the
> > > > > > > > > startOffset
> > > > > > > > > > > to
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > middle of a segment. If we copy the full segment
> to
> > > > remote
> > > > > > > > > storage,
> > > > > > > > > > > the
> > > > > > > > > > > > > > baseOffset and the startOffset will be different.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Good point. startOffset is baseOffset by
> default, if
> > > > not
> > > > > > set
> > > > > > > > > > > explicitly.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5102.7 Could we define all the public methods for
> > > > > > > > > > > > > RemoteLogSegmentMetadata
> > > > > > > > > > > > > > and LogSegmentData?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Sure, updated the wiki.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5102.8 Could we document whether endOffset in
> > > > > > > > > > > RemoteLogSegmentMetadata is
> > > > > > > > > > > > > > inclusive/exclusive?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > It is inclusive, will update.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5103. configs:
> > > > > > > > > > > > > > 5103.1 Could we define the default value of
> > > > non-required
> > > > > > > > configs
> > > > > > > > > > > (e.g the
> > > > > > > > > > > > > > size of new thread pools)?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Sure, that makes sense.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5103.2 It seems that local.log.retention.ms
> should
> > > > > > default to
> > > > > > > > > > > > > retention.ms,
> > > > > > > > > > > > > > instead of remote.log.retention.minutes.
> Similarly,
> > > it
> > > > > > seems
> > > > > > > > > > > > > > that local.log.retention.bytes should default to
> > > > > > segment.bytes.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Right, we do not have  remote.log.retention as we
> > > > discussed
> > > > > > > > > earlier.
> > > > > > > > > > > > > > Thanks for catching the typo.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5103.3 remote.log.manager.thread.pool.size: The
> > > > description
> > > > > > > > says
> > > > > > > > > > > "used in
> > > > > > > > > > > > > > scheduling tasks to copy segments, fetch remote
> log
> > > > > > indexes and
> > > > > > > > > > > clean up
> > > > > > > > > > > > > > remote log segments". However, there is a
> separate
> > > > > > > > > > > > > > config remote.log.reader.threads for fetching
> remote
> > > > data.
> > > > > > It's
> > > > > > > > > > > weird to
> > > > > > > > > > > > > > fetch remote index and log in different thread
> pools
> > > > since
> > > > > > both
> > > > > > > > > are
> > > > > > > > > > > used
> > > > > > > > > > > > > > for serving fetch requests.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Right, remote.log.manager.thread.pool is mainly
> used
> > > > for
> > > > > > > > > copy/cleanup
> > > > > > > > > > > > > > activities. Fetch path always goes through
> > > > > > > > > remote.log.reader.threads.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5103.4 remote.log.manager.task.interval.ms: Is
> that
> > > > the
> > > > > > amount
> > > > > > > > > of
> > > > > > > > > > > time
> > > > > > > > > > > > > to
> > > > > > > > > > > > > > back off when there is no work to do? If so,
> perhaps
> > > it
> > > > > > can be
> > > > > > > > > > > renamed as
> > > > > > > > > > > > > > backoff.ms.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > This is the delay interval for each iteration.
> It may
> > > > be
> > > > > > > > renamed
> > > > > > > > > to
> > > > > > > > > > > > > > remote.log.manager.task.delay.ms
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5103.5 Are rlm_process_interval_ms and
> > > > > > rlm_retry_interval_ms
> > > > > > > > > > > configs? If
> > > > > > > > > > > > > > so, they need to be listed in this section.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > remote.log.manager.task.interval.ms is the
> process
> > > > > > internal,
> > > > > > > > > retry
> > > > > > > > > > > > > > interval is missing in the configs, which will be
> > > > updated
> > > > > > in
> > > > > > > > the
> > > > > > > > > KIP.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5104. "RLM maintains a bounded cache(possibly
> LRU) of
> > > > the
> > > > > > index
> > > > > > > > > > > files of
> > > > > > > > > > > > > > remote log segments to avoid multiple index
> fetches
> > > > from
> > > > > > the
> > > > > > > > > remote
> > > > > > > > > > > > > > storage." Is the RLM in memory or on disk? If on
> > > disk,
> > > > > > where is
> > > > > > > > > it
> > > > > > > > > > > > > stored?
> > > > > > > > > > > > > > Do we need a configuration to bound the size?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > It is stored on disk. They are stored in a
> directory
> > > > > > > > > > > > > > `remote-log-index-cache` under log dir. We plan
> to
> > > > have a
> > > > > > > > config
> > > > > > > > > for
> > > > > > > > > > > > > > that instead of default. We will have a
> configuration
> > > > for
> > > > > > that.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5105. The KIP uses local-log-start-offset and
> > > Earliest
> > > > > > Local
> > > > > > > > > Offset
> > > > > > > > > > > in
> > > > > > > > > > > > > > different places. It would be useful to
> standardize
> > > the
> > > > > > > > > terminology.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Sure.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5106. The section on "In BuildingRemoteLogAux
> state".
> > > > It
> > > > > > listed
> > > > > > > > > two
> > > > > > > > > > > > > options
> > > > > > > > > > > > > > without saying which option is chosen.
> > > > > > > > > > > > > > We already mentioned in the KIP that we chose
> > > option-2.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5107. Follower to leader transition: It has step
> 2,
> > > > but not
> > > > > > > > step
> > > > > > > > > 1.
> > > > > > > > > > > > > > Step-1 is there but it is not explicitly
> highlighted.
> > > > It is
> > > > > > > > > previous
> > > > > > > > > > > > > > table to step-2.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5108. If a consumer fetches from the remote data
> and
> > > > the
> > > > > > remote
> > > > > > > > > > > storage
> > > > > > > > > > > > > is
> > > > > > > > > > > > > > not available, what error code is used in the
> fetch
> > > > > > response?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Good point. We have not yet defined the error for
> > > this
> > > > > > case. We
> > > > > > > > > need
> > > > > > > > > > > > > > to define an error message and send the same in
> fetch
> > > > > > response.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5109. "ListOffsets: For timestamps >= 0, it
> returns
> > > the
> > > > > > first
> > > > > > > > > message
> > > > > > > > > > > > > > offset whose timestamp is >= to the given
> timestamp
> > > in
> > > > the
> > > > > > > > > request.
> > > > > > > > > > > That
> > > > > > > > > > > > > > means it checks in remote log time indexes first,
> > > after
> > > > > > which
> > > > > > > > > local
> > > > > > > > > > > log
> > > > > > > > > > > > > > time indexes are checked." Could you document
> which
> > > > method
> > > > > > in
> > > > > > > > > RLMM is
> > > > > > > > > > > > > used
> > > > > > > > > > > > > > for this?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Okay.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5110. Stopreplica: "it sets all the remote log
> > > segment
> > > > > > metadata
> > > > > > > > > of
> > > > > > > > > > > that
> > > > > > > > > > > > > > partition with a delete marker and publishes
> them to
> > > > RLMM."
> > > > > > > > This
> > > > > > > > > > > seems
> > > > > > > > > > > > > > outdated given the new topic deletion logic.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Will update with KIP-516 related points.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5111. "RLM follower fetches the earliest offset
> for
> > > the
> > > > > > > > earliest
> > > > > > > > > > > leader
> > > > > > > > > > > > > > epoch by calling
> > > RLMM.earliestLogOffset(TopicPartition
> > > > > > > > > > > topicPartition,
> > > > > > > > > > > > > int
> > > > > > > > > > > > > > leaderEpoch) and updates that as the log start
> > > > offset." Do
> > > > > > we
> > > > > > > > > need
> > > > > > > > > > > that
> > > > > > > > > > > > > > since replication propagates logStartOffset
> already?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Good point. Right, existing replication protocol
> > > takes
> > > > > > care of
> > > > > > > > > > > > > > updating the followers’s log start offset
> received
> > > > from the
> > > > > > > > > leader.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5112. Is the default maxWaitMs of 500ms enough
> for
> > > > fetching
> > > > > > > > from
> > > > > > > > > > > remote
> > > > > > > > > > > > > > storage?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Remote reads may fail within the current default
> wait
> > > > > > time, but
> > > > > > > > > > > > > > subsequent fetches would be able to serve as that
> > > data
> > > > is
> > > > > > > > stored
> > > > > > > > > in
> > > > > > > > > > > > > > the local cache. This cache is currently
> implemented
> > > in
> > > > > > RSMs.
> > > > > > > > > But we
> > > > > > > > > > > > > > plan to pull this into the remote log messaging
> layer
> > > > in
> > > > > > > > future.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5113. "Committed offsets can be stored in a local
> > > file
> > > > to
> > > > > > avoid
> > > > > > > > > > > reading
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > messages again when a broker is restarted."
> Could you
> > > > > > describe
> > > > > > > > > the
> > > > > > > > > > > format
> > > > > > > > > > > > > > and the location of the file? Also, could the
> same
> > > > message
> > > > > > be
> > > > > > > > > > > processed
> > > > > > > > > > > > > by
> > > > > > > > > > > > > > RLMM again after broker restart? If so, how do we
> > > > handle
> > > > > > that?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Sure, we will update in the KIP.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5114. Message format
> > > > > > > > > > > > > > 5114.1 There are two records named
> > > > > > > > RemoteLogSegmentMetadataRecord
> > > > > > > > > > > with
> > > > > > > > > > > > > > apiKey 0 and 1.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Nice catch, that was a typo. Fixed in the wiki.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5114.2 RemoteLogSegmentMetadataRecord: Could we
> > > > document
> > > > > > > > whether
> > > > > > > > > > > > > endOffset
> > > > > > > > > > > > > > is inclusive/exclusive?
> > > > > > > > > > > > > > It is inclusive, will update.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5114.3 RemoteLogSegmentMetadataRecord: Could you
> > > > explain
> > > > > > > > > LeaderEpoch
> > > > > > > > > > > a
> > > > > > > > > > > > > bit
> > > > > > > > > > > > > > more? Is that the epoch of the leader when it
> copies
> > > > the
> > > > > > > > segment
> > > > > > > > > to
> > > > > > > > > > > > > remote
> > > > > > > > > > > > > > storage? Also, how will this field be used?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Right, this is the leader epoch of the broker
> which
> > > > copied
> > > > > > this
> > > > > > > > > > > > > > segment. This is helpful in reason about which
> broker
> > > > > > copied
> > > > > > > > the
> > > > > > > > > > > > > > segment to remote storage.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5114.4 EventTimestamp: Could you explain this a
> bit
> > > > more?
> > > > > > Each
> > > > > > > > > > > record in
> > > > > > > > > > > > > > Kafka already has a timestamp field. Could we
> just
> > > use
> > > > > > that?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > This is the  timestamp at which  the respective
> event
> > > > > > occurred.
> > > > > > > > > Added
> > > > > > > > > > > > > > this  to RemoteLogSegmentMetadata as RLMM can
> be  any
> > > > other
> > > > > > > > > > > > > > implementation. We thought about that but it
> looked
> > > > > > cleaner to
> > > > > > > > > use at
> > > > > > > > > > > > > > the message structure level instead of getting
> that
> > > > from
> > > > > > the
> > > > > > > > > consumer
> > > > > > > > > > > > > > record and using that to build the respective
> event.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5114.5 SegmentSizeInBytes: Could this just be
> int32?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Right, it looks like config allows only int
> value >=
> > > > 14.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5115. RemoteLogCleaner(RLC): This could be
> confused
> > > > with
> > > > > > the
> > > > > > > > log
> > > > > > > > > > > cleaner
> > > > > > > > > > > > > > for compaction. Perhaps it can be renamed to sth
> like
> > > > > > > > > > > > > > RemotePartitionRemover.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > I am fine with RemotePartitionRemover or
> > > > > > > > > RemoteLogDeletionManager(we
> > > > > > > > > > > > > > have other manager classes like RLM, RLMM).
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5116. "RLC receives the delete_partition_marked
> and
> > > > > > processes
> > > > > > > > it
> > > > > > > > > if
> > > > > > > > > > > it is
> > > > > > > > > > > > > > not yet processed earlier." How does it know
> whether
> > > > > > > > > > > > > > delete_partition_marked has been processed
> earlier?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > This is to handle duplicate
> delete_partition_marked
> > > > > > events. RLC
> > > > > > > > > > > > > > internally maintains a state for the
> delete_partition
> > > > > > events
> > > > > > > > and
> > > > > > > > > if
> > > > > > > > > > > it
> > > > > > > > > > > > > > already has an existing event then it ignores if
> it
> > > is
> > > > > > already
> > > > > > > > > being
> > > > > > > > > > > > > > processed.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5117. Should we add a new MessageFormatter to
> read
> > > the
> > > > tier
> > > > > > > > > metadata
> > > > > > > > > > > > > topic?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Right, this is in plan but did not mention it in
> the
> > > > KIP.
> > > > > > This
> > > > > > > > > will
> > > > > > > > > > > be
> > > > > > > > > > > > > > useful for debugging purposes too.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5118. "Maximum remote log reader thread pool task
> > > queue
> > > > > > size.
> > > > > > > > If
> > > > > > > > > the
> > > > > > > > > > > task
> > > > > > > > > > > > > > queue is full, broker will stop reading remote
> log
> > > > > > segments."
> > > > > > > > > What
> > > > > > > > > > > do we
> > > > > > > > > > > > > > return to the fetch request in this case?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > We return an error response for that partition.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5119. It would be useful to list all things not
> > > > supported
> > > > > > in
> > > > > > > > the
> > > > > > > > > > > first
> > > > > > > > > > > > > > version in a Future work or Limitations section.
> For
> > > > > > example,
> > > > > > > > > > > compacted
> > > > > > > > > > > > > > topic, JBOD, changing remote.log.storage.enable
> from
> > > > true
> > > > > > to
> > > > > > > > > false,
> > > > > > > > > > > etc.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > We already have a non-goals section which is
> filled
> > > > with
> > > > > > some
> > > > > > > > of
> > > > > > > > > > > these
> > > > > > > > > > > > > > details. Do we need another limitations section?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > Satish.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > On Wed, Nov 4, 2020 at 11:27 PM Jun Rao <
> > > > jun@confluent.io>
> > > > > > > > > wrote:
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Hi, Satish,
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Thanks for the updated KIP. A few more comments
> > > > below.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 605.2 "Build the local leader epoch cache by
> > > cutting
> > > > the
> > > > > > > > leader
> > > > > > > > > > > epoch
> > > > > > > > > > > > > > > sequence received from remote storage to [LSO,
> > > > ELO]." I
> > > > > > > > > mentioned
> > > > > > > > > > > an
> > > > > > > > > > > > > issue
> > > > > > > > > > > > > > > earlier. Suppose the leader's local start
> offset is
> > > > 100.
> > > > > > The
> > > > > > > > > > > follower
> > > > > > > > > > > > > finds
> > > > > > > > > > > > > > > a remote segment covering offset range [80,
> 120).
> > > The
> > > > > > > > > producerState
> > > > > > > > > > > > > with
> > > > > > > > > > > > > > > this remote segment is up to offset 120. To
> trim
> > > the
> > > > > > > > > producerState
> > > > > > > > > > > to
> > > > > > > > > > > > > > > offset 100 requires more work since one needs
> to
> > > > > > download the
> > > > > > > > > > > previous
> > > > > > > > > > > > > > > producerState up to offset 80 and then replay
> the
> > > > > > messages
> > > > > > > > > from 80
> > > > > > > > > > > to
> > > > > > > > > > > > > 100.
> > > > > > > > > > > > > > > It seems that it's simpler in this case for the
> > > > follower
> > > > > > just
> > > > > > > > > to
> > > > > > > > > > > take
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > remote segment as it is and start fetching from
> > > > offset
> > > > > > 120.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5016. Just to echo what Kowshik was saying. It
> > > seems
> > > > that
> > > > > > > > > > > > > > > RLMM.onPartitionLeadershipChanges() is only
> called
> > > > on the
> > > > > > > > > replicas
> > > > > > > > > > > for
> > > > > > > > > > > > > a
> > > > > > > > > > > > > > > partition, not on the replicas for the
> > > > > > > > > > > __remote_log_segment_metadata
> > > > > > > > > > > > > > > partition. It's not clear how the leader of
> > > > > > > > > > > > > __remote_log_segment_metadata
> > > > > > > > > > > > > > > obtains the metadata for remote segments for
> > > > deletion.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5100. KIP-516 has been accepted and is being
> > > > implemented
> > > > > > now.
> > > > > > > > > > > Could you
> > > > > > > > > > > > > > > update the KIP based on topicID?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5101. RLMM: It would be useful to clarify how
> the
> > > > > > following
> > > > > > > > two
> > > > > > > > > > > APIs
> > > > > > > > > > > > > are
> > > > > > > > > > > > > > > used. According to the wiki, the former is
> used for
> > > > topic
> > > > > > > > > deletion
> > > > > > > > > > > and
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > latter is used for retention. It seems that
> > > retention
> > > > > > should
> > > > > > > > > use
> > > > > > > > > > > the
> > > > > > > > > > > > > former
> > > > > > > > > > > > > > > since remote segments without a matching epoch
> in
> > > the
> > > > > > leader
> > > > > > > > > > > > > (potentially
> > > > > > > > > > > > > > > due to unclean leader election) also need to be
> > > > garbage
> > > > > > > > > collected.
> > > > > > > > > > > The
> > > > > > > > > > > > > > > latter seems to be used for the new leader to
> > > > determine
> > > > > > the
> > > > > > > > > last
> > > > > > > > > > > tiered
> > > > > > > > > > > > > > > segment.
> > > > > > > > > > > > > > >     default Iterator<RemoteLogSegmentMetadata>
> > > > > > > > > > > > > > > listRemoteLogSegments(TopicPartition
> > > topicPartition)
> > > > > > > > > > > > > > >     Iterator<RemoteLogSegmentMetadata>
> > > > > > > > > > > > > listRemoteLogSegments(TopicPartition
> > > > > > > > > > > > > > > topicPartition, long leaderEpoch);
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5102. RSM:
> > > > > > > > > > > > > > > 5102.1 For methods like fetchLogSegmentData(),
> it
> > > > seems
> > > > > > that
> > > > > > > > > they
> > > > > > > > > > > can
> > > > > > > > > > > > > > > use RemoteLogSegmentId instead of
> > > > > > RemoteLogSegmentMetadata.
> > > > > > > > > > > > > > > 5102.2 In fetchLogSegmentData(), should we use
> long
> > > > > > instead
> > > > > > > > of
> > > > > > > > > > > Long?
> > > > > > > > > > > > > > > 5102.3 Why only some of the methods have
> default
> > > > > > > > > implementation and
> > > > > > > > > > > > > others
> > > > > > > > > > > > > > > don't?
> > > > > > > > > > > > > > > 5102.4. Could we define
> > > > RemoteLogSegmentMetadataUpdate
> > > > > > > > > > > > > > > and DeletePartitionUpdate?
> > > > > > > > > > > > > > > 5102.5 LogSegmentData: It seems that it's
> easier to
> > > > pass
> > > > > > > > > > > > > > > in leaderEpochIndex as a ByteBuffer or byte
> array
> > > > than a
> > > > > > file
> > > > > > > > > > > since it
> > > > > > > > > > > > > will
> > > > > > > > > > > > > > > be generated in memory.
> > > > > > > > > > > > > > > 5102.6 RemoteLogSegmentMetadata: It seems that
> it
> > > > needs
> > > > > > both
> > > > > > > > > > > > > baseOffset and
> > > > > > > > > > > > > > > startOffset. For example, deleteRecords() could
> > > move
> > > > the
> > > > > > > > > > > startOffset
> > > > > > > > > > > > > to the
> > > > > > > > > > > > > > > middle of a segment. If we copy the full
> segment to
> > > > > > remote
> > > > > > > > > > > storage, the
> > > > > > > > > > > > > > > baseOffset and the startOffset will be
> different.
> > > > > > > > > > > > > > > 5102.7 Could we define all the public methods
> for
> > > > > > > > > > > > > RemoteLogSegmentMetadata
> > > > > > > > > > > > > > > and LogSegmentData?
> > > > > > > > > > > > > > > 5102.8 Could we document whether endOffset in
> > > > > > > > > > > RemoteLogSegmentMetadata
> > > > > > > > > > > > > is
> > > > > > > > > > > > > > > inclusive/exclusive?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5103. configs:
> > > > > > > > > > > > > > > 5103.1 Could we define the default value of
> > > > non-required
> > > > > > > > > configs
> > > > > > > > > > > (e.g
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > size of new thread pools)?
> > > > > > > > > > > > > > > 5103.2 It seems that local.log.retention.ms
> should
> > > > > > default
> > > > > > > > to
> > > > > > > > > > > > > retention.ms,
> > > > > > > > > > > > > > > instead of remote.log.retention.minutes.
> Similarly,
> > > > it
> > > > > > seems
> > > > > > > > > > > > > > > that local.log.retention.bytes should default
> to
> > > > > > > > segment.bytes.
> > > > > > > > > > > > > > > 5103.3 remote.log.manager.thread.pool.size: The
> > > > > > description
> > > > > > > > > says
> > > > > > > > > > > "used
> > > > > > > > > > > > > in
> > > > > > > > > > > > > > > scheduling tasks to copy segments, fetch
> remote log
> > > > > > indexes
> > > > > > > > and
> > > > > > > > > > > clean
> > > > > > > > > > > > > up
> > > > > > > > > > > > > > > remote log segments". However, there is a
> separate
> > > > > > > > > > > > > > > config remote.log.reader.threads for fetching
> > > remote
> > > > > > data.
> > > > > > > > It's
> > > > > > > > > > > weird
> > > > > > > > > > > > > to
> > > > > > > > > > > > > > > fetch remote index and log in different thread
> > > pools
> > > > > > since
> > > > > > > > > both are
> > > > > > > > > > > > > used
> > > > > > > > > > > > > > > for serving fetch requests.
> > > > > > > > > > > > > > > 5103.4 remote.log.manager.task.interval.ms: Is
> > > that
> > > > the
> > > > > > > > > amount of
> > > > > > > > > > > > > time to
> > > > > > > > > > > > > > > back off when there is no work to do? If so,
> > > perhaps
> > > > it
> > > > > > can
> > > > > > > > be
> > > > > > > > > > > renamed
> > > > > > > > > > > > > as
> > > > > > > > > > > > > > > backoff.ms.
> > > > > > > > > > > > > > > 5103.5 Are rlm_process_interval_ms and
> > > > > > rlm_retry_interval_ms
> > > > > > > > > > > configs?
> > > > > > > > > > > > > If
> > > > > > > > > > > > > > > so, they need to be listed in this section.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5104. "RLM maintains a bounded cache(possibly
> LRU)
> > > > of the
> > > > > > > > index
> > > > > > > > > > > files
> > > > > > > > > > > > > of
> > > > > > > > > > > > > > > remote log segments to avoid multiple index
> fetches
> > > > from
> > > > > > the
> > > > > > > > > remote
> > > > > > > > > > > > > > > storage." Is the RLM in memory or on disk? If
> on
> > > > disk,
> > > > > > where
> > > > > > > > > is it
> > > > > > > > > > > > > stored?
> > > > > > > > > > > > > > > Do we need a configuration to bound the size?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5105. The KIP uses local-log-start-offset and
> > > > Earliest
> > > > > > Local
> > > > > > > > > > > Offset in
> > > > > > > > > > > > > > > different places. It would be useful to
> standardize
> > > > the
> > > > > > > > > > > terminology.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5106. The section on "In BuildingRemoteLogAux
> > > > state". It
> > > > > > > > > listed two
> > > > > > > > > > > > > options
> > > > > > > > > > > > > > > without saying which option is chosen.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5107. Follower to leader transition: It has
> step 2,
> > > > but
> > > > > > not
> > > > > > > > > step 1.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5108. If a consumer fetches from the remote
> data
> > > and
> > > > the
> > > > > > > > remote
> > > > > > > > > > > > > storage is
> > > > > > > > > > > > > > > not available, what error code is used in the
> fetch
> > > > > > response?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5109. "ListOffsets: For timestamps >= 0, it
> returns
> > > > the
> > > > > > first
> > > > > > > > > > > message
> > > > > > > > > > > > > > > offset whose timestamp is >= to the given
> timestamp
> > > > in
> > > > > > the
> > > > > > > > > request.
> > > > > > > > > > > > > That
> > > > > > > > > > > > > > > means it checks in remote log time indexes
> first,
> > > > after
> > > > > > which
> > > > > > > > > > > local log
> > > > > > > > > > > > > > > time indexes are checked." Could you document
> which
> > > > > > method in
> > > > > > > > > RLMM
> > > > > > > > > > > is
> > > > > > > > > > > > > used
> > > > > > > > > > > > > > > for this?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5110. Stopreplica: "it sets all the remote log
> > > > segment
> > > > > > > > > metadata of
> > > > > > > > > > > that
> > > > > > > > > > > > > > > partition with a delete marker and publishes
> them
> > > to
> > > > > > RLMM."
> > > > > > > > > This
> > > > > > > > > > > seems
> > > > > > > > > > > > > > > outdated given the new topic deletion logic.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5111. "RLM follower fetches the earliest
> offset for
> > > > the
> > > > > > > > > earliest
> > > > > > > > > > > leader
> > > > > > > > > > > > > > > epoch by calling
> > > > RLMM.earliestLogOffset(TopicPartition
> > > > > > > > > > > topicPartition,
> > > > > > > > > > > > > int
> > > > > > > > > > > > > > > leaderEpoch) and updates that as the log start
> > > > offset."
> > > > > > Do we
> > > > > > > > > need
> > > > > > > > > > > that
> > > > > > > > > > > > > > > since replication propagates logStartOffset
> > > already?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5112. Is the default maxWaitMs of 500ms enough
> for
> > > > > > fetching
> > > > > > > > > from
> > > > > > > > > > > remote
> > > > > > > > > > > > > > > storage?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5113. "Committed offsets can be stored in a
> local
> > > > file to
> > > > > > > > avoid
> > > > > > > > > > > > > reading the
> > > > > > > > > > > > > > > messages again when a broker is restarted."
> Could
> > > you
> > > > > > > > describe
> > > > > > > > > the
> > > > > > > > > > > > > format
> > > > > > > > > > > > > > > and the location of the file? Also, could the
> same
> > > > > > message be
> > > > > > > > > > > > > processed by
> > > > > > > > > > > > > > > RLMM again after broker restart? If so, how do
> we
> > > > handle
> > > > > > > > that?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5114. Message format
> > > > > > > > > > > > > > > 5114.1 There are two records named
> > > > > > > > > RemoteLogSegmentMetadataRecord
> > > > > > > > > > > with
> > > > > > > > > > > > > > > apiKey 0 and 1.
> > > > > > > > > > > > > > > 5114.2 RemoteLogSegmentMetadataRecord: Could we
> > > > document
> > > > > > > > > whether
> > > > > > > > > > > > > endOffset
> > > > > > > > > > > > > > > is inclusive/exclusive?
> > > > > > > > > > > > > > > 5114.3 RemoteLogSegmentMetadataRecord: Could
> you
> > > > explain
> > > > > > > > > > > LeaderEpoch a
> > > > > > > > > > > > > bit
> > > > > > > > > > > > > > > more? Is that the epoch of the leader when it
> > > copies
> > > > the
> > > > > > > > > segment to
> > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > storage? Also, how will this field be used?
> > > > > > > > > > > > > > > 5114.4 EventTimestamp: Could you explain this
> a bit
> > > > more?
> > > > > > > > Each
> > > > > > > > > > > record
> > > > > > > > > > > > > in
> > > > > > > > > > > > > > > Kafka already has a timestamp field. Could we
> just
> > > > use
> > > > > > that?
> > > > > > > > > > > > > > > 5114.5 SegmentSizeInBytes: Could this just be
> > > int32?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5115. RemoteLogCleaner(RLC): This could be
> confused
> > > > with
> > > > > > the
> > > > > > > > > log
> > > > > > > > > > > > > cleaner
> > > > > > > > > > > > > > > for compaction. Perhaps it can be renamed to
> sth
> > > like
> > > > > > > > > > > > > > > RemotePartitionRemover.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5116. "RLC receives the
> delete_partition_marked and
> > > > > > processes
> > > > > > > > > it
> > > > > > > > > > > if it
> > > > > > > > > > > > > is
> > > > > > > > > > > > > > > not yet processed earlier." How does it know
> > > whether
> > > > > > > > > > > > > > > delete_partition_marked has been processed
> earlier?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5117. Should we add a new MessageFormatter to
> read
> > > > the
> > > > > > tier
> > > > > > > > > > > metadata
> > > > > > > > > > > > > topic?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5118. "Maximum remote log reader thread pool
> task
> > > > queue
> > > > > > size.
> > > > > > > > > If
> > > > > > > > > > > the
> > > > > > > > > > > > > task
> > > > > > > > > > > > > > > queue is full, broker will stop reading remote
> log
> > > > > > segments."
> > > > > > > > > What
> > > > > > > > > > > do
> > > > > > > > > > > > > we
> > > > > > > > > > > > > > > return to the fetch request in this case?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5119. It would be useful to list all things not
> > > > > > supported in
> > > > > > > > > the
> > > > > > > > > > > first
> > > > > > > > > > > > > > > version in a Future work or Limitations
> section.
> > > For
> > > > > > example,
> > > > > > > > > > > compacted
> > > > > > > > > > > > > > > topic, JBOD, changing remote.log.storage.enable
> > > from
> > > > > > true to
> > > > > > > > > false,
> > > > > > > > > > > > > etc.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Jun
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > On Tue, Oct 27, 2020 at 5:57 PM Kowshik
> Prakasam <
> > > > > > > > > > > > > kprakasam@confluent.io>
> > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Hi Satish,
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Thanks for the updates to the KIP. Here are
> my
> > > > first
> > > > > > batch
> > > > > > > > of
> > > > > > > > > > > > > > > > comments/suggestions on the latest version
> of the
> > > > KIP.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 5012. In the RemoteStorageManager interface,
> > > there
> > > > is
> > > > > > an
> > > > > > > > API
> > > > > > > > > > > defined
> > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > each file type. For example,
> fetchOffsetIndex,
> > > > > > > > > > > fetchTimestampIndex
> > > > > > > > > > > > > etc. To
> > > > > > > > > > > > > > > > avoid the duplication, I'd suggest we can
> instead
> > > > have
> > > > > > a
> > > > > > > > > FileType
> > > > > > > > > > > > > enum and
> > > > > > > > > > > > > > > > a common get API based on the FileType.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 5013. There are some references to the
> Google doc
> > > > in
> > > > > > the
> > > > > > > > > KIP. I
> > > > > > > > > > > > > wasn't sure
> > > > > > > > > > > > > > > > if the Google doc is expected to be in sync
> with
> > > > the
> > > > > > > > > contents of
> > > > > > > > > > > the
> > > > > > > > > > > > > wiki.
> > > > > > > > > > > > > > > > Going forward, it seems easier if just the
> KIP is
> > > > > > > > maintained
> > > > > > > > > as
> > > > > > > > > > > the
> > > > > > > > > > > > > source
> > > > > > > > > > > > > > > > of truth. In this regard, could you please
> move
> > > > all the
> > > > > > > > > > > references
> > > > > > > > > > > > > to the
> > > > > > > > > > > > > > > > Google doc, maybe to a separate References
> > > section
> > > > at
> > > > > > the
> > > > > > > > > bottom
> > > > > > > > > > > of
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > KIP?
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 5014. There are some TODO sections in the
> KIP.
> > > > Would
> > > > > > these
> > > > > > > > be
> > > > > > > > > > > filled
> > > > > > > > > > > > > up in
> > > > > > > > > > > > > > > > future iterations?
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 5015. Under "Topic deletion lifecycle", I'm
> > > trying
> > > > to
> > > > > > > > > understand
> > > > > > > > > > > why
> > > > > > > > > > > > > do we
> > > > > > > > > > > > > > > > need delete_partition_marked as well as the
> > > > > > > > > > > delete_partition_started
> > > > > > > > > > > > > > > > messages. I couldn't spot a drawback if
> supposing
> > > > we
> > > > > > > > > simplified
> > > > > > > > > > > the
> > > > > > > > > > > > > design
> > > > > > > > > > > > > > > > such that the controller would only write
> > > > > > > > > > > delete_partition_started
> > > > > > > > > > > > > message,
> > > > > > > > > > > > > > > > and RemoteLogCleaner (RLC) instance picks it
> up
> > > for
> > > > > > > > > processing.
> > > > > > > > > > > What
> > > > > > > > > > > > > am I
> > > > > > > > > > > > > > > > missing?
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 5016. Under "Topic deletion lifecycle", step
> (4)
> > > is
> > > > > > > > > mentioned as
> > > > > > > > > > > > > "RLC gets
> > > > > > > > > > > > > > > > all the remote log segments for the
> partition and
> > > > each
> > > > > > of
> > > > > > > > > these
> > > > > > > > > > > > > remote log
> > > > > > > > > > > > > > > > segments is deleted with the next steps.".
> Since
> > > > the
> > > > > > RLC
> > > > > > > > > instance
> > > > > > > > > > > > > runs on
> > > > > > > > > > > > > > > > each tier topic partition leader, how does
> the
> > > RLC
> > > > > > then get
> > > > > > > > > the
> > > > > > > > > > > list
> > > > > > > > > > > > > of
> > > > > > > > > > > > > > > > remote log segments to be deleted? It will be
> > > > useful
> > > > > > to add
> > > > > > > > > that
> > > > > > > > > > > > > detail to
> > > > > > > > > > > > > > > > the KIP.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 5017. Under "Public Interfaces -> Configs",
> there
> > > > is a
> > > > > > line
> > > > > > > > > > > > > mentioning "We
> > > > > > > > > > > > > > > > will support flipping
> remote.log.storage.enable
> > > in
> > > > next
> > > > > > > > > > > versions."
> > > > > > > > > > > > > It will
> > > > > > > > > > > > > > > > be useful to mention this in the "Future
> Work"
> > > > section
> > > > > > of
> > > > > > > > > the KIP
> > > > > > > > > > > > > too.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 5018. The KIP introduces a number of
> > > configuration
> > > > > > > > > parameters. It
> > > > > > > > > > > > > will be
> > > > > > > > > > > > > > > > useful to mention in the KIP if the user
> should
> > > > assume
> > > > > > > > these
> > > > > > > > > as
> > > > > > > > > > > > > static
> > > > > > > > > > > > > > > > configuration in the server.properties file,
> or
> > > > dynamic
> > > > > > > > > > > > > configuration which
> > > > > > > > > > > > > > > > can be modified without restarting the
> broker.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 5019.  Maybe this is planned as a future
> update
> > > to
> > > > the
> > > > > > KIP,
> > > > > > > > > but I
> > > > > > > > > > > > > thought
> > > > > > > > > > > > > > > > I'd mention it here. Could you please add
> details
> > > > to
> > > > > > the
> > > > > > > > KIP
> > > > > > > > > on
> > > > > > > > > > > why
> > > > > > > > > > > > > RocksDB
> > > > > > > > > > > > > > > > was chosen as the default cache
> implementation of
> > > > > > RLMM, and
> > > > > > > > > how
> > > > > > > > > > > it
> > > > > > > > > > > > > is going
> > > > > > > > > > > > > > > > to be used? Were alternatives
> > > compared/considered?
> > > > For
> > > > > > > > > example,
> > > > > > > > > > > it
> > > > > > > > > > > > > would be
> > > > > > > > > > > > > > > > useful to explain/evaluate the following: 1)
> > > > > > debuggability
> > > > > > > > > of the
> > > > > > > > > > > > > RocksDB
> > > > > > > > > > > > > > > > JNI interface, 2) performance, 3) portability
> > > > across
> > > > > > > > > platforms
> > > > > > > > > > > and 4)
> > > > > > > > > > > > > > > > interface parity of RocksDB’s JNI api with
> it's
> > > > > > underlying
> > > > > > > > > C/C++
> > > > > > > > > > > api.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 5020. Following up on (5019), for the RocksDB
> > > > cache, it
> > > > > > > > will
> > > > > > > > > be
> > > > > > > > > > > > > useful to
> > > > > > > > > > > > > > > > explain the relationship/mapping between the
> > > > following
> > > > > > in
> > > > > > > > the
> > > > > > > > > > > KIP:
> > > > > > > > > > > > > 1) # of
> > > > > > > > > > > > > > > > tiered partitions, 2) # of partitions of
> metadata
> > > > topic
> > > > > > > > > > > > > > > > __remote_log_metadata and 3) # of RocksDB
> > > > instances.
> > > > > > i.e.
> > > > > > > > is
> > > > > > > > > the
> > > > > > > > > > > > > plan to
> > > > > > > > > > > > > > > > have a RocksDB instance per tiered
> partition, or
> > > > per
> > > > > > > > metadata
> > > > > > > > > > > topic
> > > > > > > > > > > > > > > > partition, or just 1 for per broker?
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 5021. I was looking at the implementation
> > > > prototype (PR
> > > > > > > > link:
> > > > > > > > > > > > > > > > https://github.com/apache/kafka/pull/7561).
> It
> > > > seems
> > > > > > that
> > > > > > > > a
> > > > > > > > > > > boolean
> > > > > > > > > > > > > > > > attribute is being introduced into the Log
> layer
> > > to
> > > > > > check
> > > > > > > > if
> > > > > > > > > > > remote
> > > > > > > > > > > > > log
> > > > > > > > > > > > > > > > capability is enabled. While the boolean
> > > footprint
> > > > is
> > > > > > small
> > > > > > > > > at
> > > > > > > > > > > the
> > > > > > > > > > > > > moment,
> > > > > > > > > > > > > > > > this can easily grow in the future and become
> > > > harder to
> > > > > > > > > > > > > > > > test/maintain, considering that the Log
> layer is
> > > > > > already
> > > > > > > > > pretty
> > > > > > > > > > > > > complex. We
> > > > > > > > > > > > > > > > should start thinking about how to manage
> such
> > > > changes
> > > > > > to
> > > > > > > > > the Log
> > > > > > > > > > > > > layer
> > > > > > > > > > > > > > > > (for the purpose of improved testability,
> better
> > > > > > separation
> > > > > > > > > of
> > > > > > > > > > > > > concerns and
> > > > > > > > > > > > > > > > readability). One proposal I have is to take
> a
> > > step
> > > > > > back
> > > > > > > > and
> > > > > > > > > > > define a
> > > > > > > > > > > > > > > > higher level Log interface. Then, the Broker
> code
> > > > can
> > > > > > be
> > > > > > > > > changed
> > > > > > > > > > > to
> > > > > > > > > > > > > use
> > > > > > > > > > > > > > > > this interface. It can be changed such that
> only
> > > a
> > > > > > handle
> > > > > > > > to
> > > > > > > > > the
> > > > > > > > > > > > > interface
> > > > > > > > > > > > > > > > is exposed to other components (such as
> > > LogCleaner,
> > > > > > > > > > > ReplicaManager
> > > > > > > > > > > > > etc.)
> > > > > > > > > > > > > > > > and not the underlying Log object. This
> approach
> > > > keeps
> > > > > > the
> > > > > > > > > user
> > > > > > > > > > > of
> > > > > > > > > > > > > the Log
> > > > > > > > > > > > > > > > layer agnostic of the whereabouts of the
> data.
> > > > > > Underneath
> > > > > > > > the
> > > > > > > > > > > > > interface,
> > > > > > > > > > > > > > > > the implementing classes can completely
> separate
> > > > local
> > > > > > log
> > > > > > > > > > > > > capabilities
> > > > > > > > > > > > > > > > from the remote log. For example, the Log
> class
> > > > can be
> > > > > > > > > > > simplified to
> > > > > > > > > > > > > only
> > > > > > > > > > > > > > > > manage logic surrounding local log segments
> and
> > > > > > metadata.
> > > > > > > > > > > > > Additionally, a
> > > > > > > > > > > > > > > > wrapper class can be provided (implementing
> the
> > > > higher
> > > > > > > > level
> > > > > > > > > Log
> > > > > > > > > > > > > interface)
> > > > > > > > > > > > > > > > which will contain any/all logic surrounding
> > > tiered
> > > > > > data.
> > > > > > > > The
> > > > > > > > > > > wrapper
> > > > > > > > > > > > > > > > class will wrap around an instance of the Log
> > > class
> > > > > > > > > delegating
> > > > > > > > > > > the
> > > > > > > > > > > > > local
> > > > > > > > > > > > > > > > log logic to it. Finally, a handle to the
> wrapper
> > > > > > class can
> > > > > > > > > be
> > > > > > > > > > > > > exposed to
> > > > > > > > > > > > > > > > the other components wherever they need a
> handle
> > > > to the
> > > > > > > > > higher
> > > > > > > > > > > level
> > > > > > > > > > > > > Log
> > > > > > > > > > > > > > > > interface.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Cheers,
> > > > > > > > > > > > > > > > Kowshik
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > On Mon, Oct 26, 2020 at 9:52 PM Satish
> Duggana <
> > > > > > > > > > > > > satish.duggana@gmail.com>
> > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Hi,
> > > > > > > > > > > > > > > > > KIP is updated with 1) topic deletion
> lifecycle
> > > > and
> > > > > > its
> > > > > > > > > related
> > > > > > > > > > > > > items
> > > > > > > > > > > > > > > > > 2) Protocol changes(mainly related to
> > > > ListOffsets)
> > > > > > and
> > > > > > > > > other
> > > > > > > > > > > minor
> > > > > > > > > > > > > > > > > changes.
> > > > > > > > > > > > > > > > > Please go through them and let us know your
> > > > comments.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > > Satish.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > On Mon, Sep 28, 2020 at 9:10 PM Satish
> Duggana
> > > <
> > > > > > > > > > > > > satish.duggana@gmail.com
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > Hi Dhruvil,
> > > > > > > > > > > > > > > > > > Thanks for looking into the KIP and
> sending
> > > > your
> > > > > > > > > comments.
> > > > > > > > > > > Sorry
> > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > > > the late reply, missed it in the mail
> thread.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > 1. Could you describe how retention would
> > > work
> > > > with
> > > > > > > > this
> > > > > > > > > KIP
> > > > > > > > > > > and
> > > > > > > > > > > > > which
> > > > > > > > > > > > > > > > > > threads are responsible for driving this
> > > work?
> > > > I
> > > > > > > > believe
> > > > > > > > > > > there
> > > > > > > > > > > > > are 3
> > > > > > > > > > > > > > > > > kinds
> > > > > > > > > > > > > > > > > > of retention processes we are looking at:
> > > > > > > > > > > > > > > > > >   (a) Regular retention for data in
> tiered
> > > > storage
> > > > > > as
> > > > > > > > per
> > > > > > > > > > > > > configured `
> > > > > > > > > > > > > > > > > > retention.ms` / `retention.bytes`.
> > > > > > > > > > > > > > > > > >   (b) Local retention for data in local
> > > > storage as
> > > > > > per
> > > > > > > > > > > > > configured `
> > > > > > > > > > > > > > > > > > local.log.retention.ms` /
> > > > > > `local.log.retention.bytes`
> > > > > > > > > > > > > > > > > >   (c) Possibly regular retention for
> data in
> > > > local
> > > > > > > > > storage,
> > > > > > > > > > > if
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > tiering
> > > > > > > > > > > > > > > > > > task is lagging or for data that is
> below the
> > > > log
> > > > > > start
> > > > > > > > > > > offset.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > Local log retention is done by the
> existing
> > > log
> > > > > > cleanup
> > > > > > > > > > > tasks.
> > > > > > > > > > > > > These
> > > > > > > > > > > > > > > > > > are not done for segments that are not
> yet
> > > > copied
> > > > > > to
> > > > > > > > > remote
> > > > > > > > > > > > > storage.
> > > > > > > > > > > > > > > > > > Remote log cleanup is done by the leader
> > > > > > partition’s
> > > > > > > > > RLMTask.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > 2. When does a segment become eligible
> to be
> > > > > > tiered? Is
> > > > > > > > > it as
> > > > > > > > > > > > > soon as
> > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > segment is rolled and the end offset is
> less
> > > > than
> > > > > > the
> > > > > > > > > last
> > > > > > > > > > > stable
> > > > > > > > > > > > > > > > offset
> > > > > > > > > > > > > > > > > as
> > > > > > > > > > > > > > > > > > mentioned in the KIP? I wonder if we
> need to
> > > > > > consider
> > > > > > > > > other
> > > > > > > > > > > > > parameters
> > > > > > > > > > > > > > > > > too,
> > > > > > > > > > > > > > > > > > like the highwatermark so that we are
> > > > guaranteed
> > > > > > that
> > > > > > > > > what
> > > > > > > > > > > we are
> > > > > > > > > > > > > > > > tiering
> > > > > > > > > > > > > > > > > > has been committed to the log and
> accepted by
> > > > the
> > > > > > ISR.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > AFAIK, last stable offset is always <=
> > > > > > highwatermark.
> > > > > > > > > This
> > > > > > > > > > > will
> > > > > > > > > > > > > make
> > > > > > > > > > > > > > > > > > sure we are always tiering the message
> > > segments
> > > > > > which
> > > > > > > > > have
> > > > > > > > > > > been
> > > > > > > > > > > > > > > > > > accepted by ISR and transactionally
> > > completed.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > 3. The section on "Follower Fetch
> Scenarios"
> > > is
> > > > > > useful
> > > > > > > > > but
> > > > > > > > > > > is a
> > > > > > > > > > > > > bit
> > > > > > > > > > > > > > > > > > difficult to parse at the moment. It
> would be
> > > > > > useful to
> > > > > > > > > > > > > summarize the
> > > > > > > > > > > > > > > > > > changes we need in the ReplicaFetcher.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > It may become difficult for users to
> > > > read/follow
> > > > > > if we
> > > > > > > > > add
> > > > > > > > > > > code
> > > > > > > > > > > > > changes
> > > > > > > > > > > > > > > > > here.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > 4. Related to the above, it's a bit
> unclear
> > > > how we
> > > > > > are
> > > > > > > > > > > planning
> > > > > > > > > > > > > on
> > > > > > > > > > > > > > > > > > restoring the producer state for a new
> > > replica.
> > > > > > Could
> > > > > > > > you
> > > > > > > > > > > expand
> > > > > > > > > > > > > on
> > > > > > > > > > > > > > > > that?
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > It is mentioned in the KIP
> > > > > > BuildingRemoteLogAuxState is
> > > > > > > > > > > > > introduced to
> > > > > > > > > > > > > > > > > > build the state like leader epoch
> sequence
> > > and
> > > > > > producer
> > > > > > > > > > > snapshots
> > > > > > > > > > > > > > > > > > before it starts fetching the data from
> the
> > > > > > leader. We
> > > > > > > > > will
> > > > > > > > > > > make
> > > > > > > > > > > > > it
> > > > > > > > > > > > > > > > > > clear in the KIP.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > 5. Similarly, it would be worth
> summarizing
> > > the
> > > > > > > > behavior
> > > > > > > > > on
> > > > > > > > > > > > > unclean
> > > > > > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > > > election. There are several scenarios to
> > > > consider
> > > > > > here:
> > > > > > > > > data
> > > > > > > > > > > > > loss from
> > > > > > > > > > > > > > > > > > local log, data loss from remote log,
> data
> > > loss
> > > > > > from
> > > > > > > > > metadata
> > > > > > > > > > > > > topic,
> > > > > > > > > > > > > > > > etc.
> > > > > > > > > > > > > > > > > > It's worth describing these in detail.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > We mentioned the cases about unclean
> leader
> > > > > > election in
> > > > > > > > > the
> > > > > > > > > > > > > follower
> > > > > > > > > > > > > > > > > > fetch scenarios.
> > > > > > > > > > > > > > > > > > If there are errors while fetching data
> from
> > > > remote
> > > > > > > > > store or
> > > > > > > > > > > > > metadata
> > > > > > > > > > > > > > > > > > store, it will work the same way as it
> works
> > > > with
> > > > > > local
> > > > > > > > > log.
> > > > > > > > > > > It
> > > > > > > > > > > > > > > > > > returns the error back to the caller.
> Please
> > > > let us
> > > > > > > > know
> > > > > > > > > if
> > > > > > > > > > > I am
> > > > > > > > > > > > > > > > > > missing your point here.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > 7. For a READ_COMMITTED FetchRequest,
> how do
> > > we
> > > > > > > > retrieve
> > > > > > > > > and
> > > > > > > > > > > > > return the
> > > > > > > > > > > > > > > > > > aborted transaction metadata?
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > When a fetch for a remote log is
> accessed, we
> > > > will
> > > > > > > > fetch
> > > > > > > > > > > aborted
> > > > > > > > > > > > > > > > > > transactions along with the segment if
> it is
> > > > not
> > > > > > found
> > > > > > > > > in the
> > > > > > > > > > > > > local
> > > > > > > > > > > > > > > > > > index cache. This includes the case of
> > > > transaction
> > > > > > > > index
> > > > > > > > > not
> > > > > > > > > > > > > existing
> > > > > > > > > > > > > > > > > > in the remote log segment. That means,
> the
> > > > cache
> > > > > > entry
> > > > > > > > > can be
> > > > > > > > > > > > > empty or
> > > > > > > > > > > > > > > > > > have a list of aborted transactions.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > 8. The `LogSegmentData` class assumes
> that we
> > > > have
> > > > > > a
> > > > > > > > log
> > > > > > > > > > > segment,
> > > > > > > > > > > > > > > > offset
> > > > > > > > > > > > > > > > > > index, time index, transaction index,
> > > producer
> > > > > > snapshot
> > > > > > > > > and
> > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > epoch
> > > > > > > > > > > > > > > > > > index. How do we deal with cases where
> we do
> > > > not
> > > > > > have
> > > > > > > > > one or
> > > > > > > > > > > > > more of
> > > > > > > > > > > > > > > > > these?
> > > > > > > > > > > > > > > > > > For example, we may not have a
> transaction
> > > > index or
> > > > > > > > > producer
> > > > > > > > > > > > > snapshot
> > > > > > > > > > > > > > > > > for a
> > > > > > > > > > > > > > > > > > particular segment. The former is
> optional,
> > > > and the
> > > > > > > > > latter is
> > > > > > > > > > > > > only kept
> > > > > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > > > up to the 3 latest segments.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > This is a good point,  we discussed this
> in
> > > the
> > > > > > last
> > > > > > > > > meeting.
> > > > > > > > > > > > > > > > > > Transaction index is optional and we will
> > > copy
> > > > them
> > > > > > > > only
> > > > > > > > > if
> > > > > > > > > > > it
> > > > > > > > > > > > > exists.
> > > > > > > > > > > > > > > > > > We want to keep all the producer
> snapshots at
> > > > each
> > > > > > log
> > > > > > > > > > > segment
> > > > > > > > > > > > > rolling
> > > > > > > > > > > > > > > > > > and they can be removed if the log
> copying is
> > > > > > > > successful
> > > > > > > > > and
> > > > > > > > > > > it
> > > > > > > > > > > > > still
> > > > > > > > > > > > > > > > > > maintains the existing latest 3
> segments, We
> > > > only
> > > > > > > > delete
> > > > > > > > > the
> > > > > > > > > > > > > producer
> > > > > > > > > > > > > > > > > > snapshots which have been copied to
> remote
> > > log
> > > > > > segments
> > > > > > > > > on
> > > > > > > > > > > > > leader.
> > > > > > > > > > > > > > > > > > Follower will keep the log segments
> beyond
> > > the
> > > > > > segments
> > > > > > > > > which
> > > > > > > > > > > > > have not
> > > > > > > > > > > > > > > > > > been copied to remote storage. We will
> update
> > > > the
> > > > > > KIP
> > > > > > > > > with
> > > > > > > > > > > these
> > > > > > > > > > > > > > > > > > details.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > > > Satish.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > On Thu, Sep 17, 2020 at 1:47 AM Dhruvil
> Shah
> > > <
> > > > > > > > > > > > > dhruvil@confluent.io>
> > > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Hi Satish, Harsha,
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Thanks for the KIP. Few questions
> below:
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 1. Could you describe how retention
> would
> > > > work
> > > > > > with
> > > > > > > > > this
> > > > > > > > > > > KIP
> > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > which
> > > > > > > > > > > > > > > > > > > threads are responsible for driving
> this
> > > > work? I
> > > > > > > > > believe
> > > > > > > > > > > there
> > > > > > > > > > > > > are 3
> > > > > > > > > > > > > > > > > kinds
> > > > > > > > > > > > > > > > > > > of retention processes we are looking
> at:
> > > > > > > > > > > > > > > > > > >   (a) Regular retention for data in
> tiered
> > > > > > storage as
> > > > > > > > > per
> > > > > > > > > > > > > configured
> > > > > > > > > > > > > > > > `
> > > > > > > > > > > > > > > > > > > retention.ms` / `retention.bytes`.
> > > > > > > > > > > > > > > > > > >   (b) Local retention for data in local
> > > > storage
> > > > > > as
> > > > > > > > per
> > > > > > > > > > > > > configured `
> > > > > > > > > > > > > > > > > > > local.log.retention.ms` /
> > > > > > > > `local.log.retention.bytes`
> > > > > > > > > > > > > > > > > > >   (c) Possibly regular retention for
> data
> > > in
> > > > > > local
> > > > > > > > > > > storage, if
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > tiering
> > > > > > > > > > > > > > > > > > > task is lagging or for data that is
> below
> > > > the log
> > > > > > > > start
> > > > > > > > > > > offset.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 2. When does a segment become eligible
> to
> > > be
> > > > > > tiered?
> > > > > > > > > Is it
> > > > > > > > > > > as
> > > > > > > > > > > > > soon as
> > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > segment is rolled and the end offset is
> > > less
> > > > > > than the
> > > > > > > > > last
> > > > > > > > > > > > > stable
> > > > > > > > > > > > > > > > > offset as
> > > > > > > > > > > > > > > > > > > mentioned in the KIP? I wonder if we
> need
> > > to
> > > > > > consider
> > > > > > > > > other
> > > > > > > > > > > > > > > > parameters
> > > > > > > > > > > > > > > > > too,
> > > > > > > > > > > > > > > > > > > like the highwatermark so that we are
> > > > guaranteed
> > > > > > that
> > > > > > > > > what
> > > > > > > > > > > we
> > > > > > > > > > > > > are
> > > > > > > > > > > > > > > > > tiering
> > > > > > > > > > > > > > > > > > > has been committed to the log and
> accepted
> > > > by the
> > > > > > > > ISR.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 3. The section on "Follower Fetch
> > > Scenarios"
> > > > is
> > > > > > > > useful
> > > > > > > > > but
> > > > > > > > > > > is
> > > > > > > > > > > > > a bit
> > > > > > > > > > > > > > > > > > > difficult to parse at the moment. It
> would
> > > be
> > > > > > useful
> > > > > > > > to
> > > > > > > > > > > > > summarize the
> > > > > > > > > > > > > > > > > > > changes we need in the ReplicaFetcher.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 4. Related to the above, it's a bit
> unclear
> > > > how
> > > > > > we
> > > > > > > > are
> > > > > > > > > > > > > planning on
> > > > > > > > > > > > > > > > > > > restoring the producer state for a new
> > > > replica.
> > > > > > Could
> > > > > > > > > you
> > > > > > > > > > > > > expand on
> > > > > > > > > > > > > > > > > that?
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 5. Similarly, it would be worth
> summarizing
> > > > the
> > > > > > > > > behavior on
> > > > > > > > > > > > > unclean
> > > > > > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > > > > election. There are several scenarios
> to
> > > > consider
> > > > > > > > here:
> > > > > > > > > > > data
> > > > > > > > > > > > > loss
> > > > > > > > > > > > > > > > from
> > > > > > > > > > > > > > > > > > > local log, data loss from remote log,
> data
> > > > loss
> > > > > > from
> > > > > > > > > > > metadata
> > > > > > > > > > > > > topic,
> > > > > > > > > > > > > > > > > etc.
> > > > > > > > > > > > > > > > > > > It's worth describing these in detail.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 6. It would be useful to add details
> about
> > > > how we
> > > > > > > > plan
> > > > > > > > > on
> > > > > > > > > > > using
> > > > > > > > > > > > > > > > > RocksDB in
> > > > > > > > > > > > > > > > > > > the default implementation of
> > > > > > > > > `RemoteLogMetadataManager`.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 7. For a READ_COMMITTED FetchRequest,
> how
> > > do
> > > > we
> > > > > > > > > retrieve
> > > > > > > > > > > and
> > > > > > > > > > > > > return
> > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > aborted transaction metadata?
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 8. The `LogSegmentData` class assumes
> that
> > > we
> > > > > > have a
> > > > > > > > > log
> > > > > > > > > > > > > segment,
> > > > > > > > > > > > > > > > > offset
> > > > > > > > > > > > > > > > > > > index, time index, transaction index,
> > > > producer
> > > > > > > > > snapshot and
> > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > > epoch
> > > > > > > > > > > > > > > > > > > index. How do we deal with cases where
> we
> > > do
> > > > not
> > > > > > have
> > > > > > > > > one
> > > > > > > > > > > or
> > > > > > > > > > > > > more of
> > > > > > > > > > > > > > > > > these?
> > > > > > > > > > > > > > > > > > > For example, we may not have a
> transaction
> > > > index
> > > > > > or
> > > > > > > > > > > producer
> > > > > > > > > > > > > snapshot
> > > > > > > > > > > > > > > > > for a
> > > > > > > > > > > > > > > > > > > particular segment. The former is
> optional,
> > > > and
> > > > > > the
> > > > > > > > > latter
> > > > > > > > > > > is
> > > > > > > > > > > > > only
> > > > > > > > > > > > > > > > > kept for
> > > > > > > > > > > > > > > > > > > up to the 3 latest segments.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > > > > Dhruvil
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > On Mon, Sep 7, 2020 at 6:54 PM Harsha
> Ch <
> > > > > > > > > > > harsha.ch@gmail.com>
> > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > Hi All,
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > We are all working through the last
> > > meeting
> > > > > > > > feedback.
> > > > > > > > > > > I'll
> > > > > > > > > > > > > cancel
> > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > > tomorrow 's meeting and we can
> meanwhile
> > > > > > continue
> > > > > > > > our
> > > > > > > > > > > > > discussion in
> > > > > > > > > > > > > > > > > mailing
> > > > > > > > > > > > > > > > > > > > list. We can start the regular
> meeting
> > > from
> > > > > > next
> > > > > > > > week
> > > > > > > > > > > > > onwards.
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > Harsha
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > On Fri, Sep 04, 2020 at 8:41 AM,
> Satish
> > > > > > Duggana <
> > > > > > > > > > > > > > > > > satish.duggana@gmail.com
> > > > > > > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > Hi Jun,
> > > > > > > > > > > > > > > > > > > > > Thanks for your thorough review and
> > > > comments.
> > > > > > > > > Please
> > > > > > > > > > > find
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > inline
> > > > > > > > > > > > > > > > > > > > > replies below.
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > 600. The topic deletion logic needs
> > > more
> > > > > > details.
> > > > > > > > > > > > > > > > > > > > > 600.1 The KIP mentions "The
> controller
> > > > > > considers
> > > > > > > > > the
> > > > > > > > > > > topic
> > > > > > > > > > > > > > > > > partition is
> > > > > > > > > > > > > > > > > > > > > deleted only when it determines
> that
> > > > there
> > > > > > are no
> > > > > > > > > log
> > > > > > > > > > > > > segments
> > > > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > > that
> > > > > > > > > > > > > > > > > > > > > topic partition by using RLMM".
> How is
> > > > this
> > > > > > done?
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > It uses RLMM#listSegments()
> returns all
> > > > the
> > > > > > > > > segments
> > > > > > > > > > > for
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > given
> > > > > > > > > > > > > > > > > topic
> > > > > > > > > > > > > > > > > > > > > partition.
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > 600.2 "If the delete option is
> enabled
> > > > then
> > > > > > the
> > > > > > > > > leader
> > > > > > > > > > > > > will stop
> > > > > > > > > > > > > > > > > RLM task
> > > > > > > > > > > > > > > > > > > > > and stop processing and it sets
> all the
> > > > > > remote
> > > > > > > > log
> > > > > > > > > > > segment
> > > > > > > > > > > > > > > > > metadata of
> > > > > > > > > > > > > > > > > > > > > that partition with a delete
> marker and
> > > > > > publishes
> > > > > > > > > them
> > > > > > > > > > > to
> > > > > > > > > > > > > RLMM."
> > > > > > > > > > > > > > > > We
> > > > > > > > > > > > > > > > > > > > > discussed this earlier. When a
> topic is
> > > > being
> > > > > > > > > deleted,
> > > > > > > > > > > > > there may
> > > > > > > > > > > > > > > > > not be a
> > > > > > > > > > > > > > > > > > > > > leader for the deleted partition.
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > This is a good point. As suggested
> in
> > > the
> > > > > > > > meeting,
> > > > > > > > > we
> > > > > > > > > > > will
> > > > > > > > > > > > > add a
> > > > > > > > > > > > > > > > > separate
> > > > > > > > > > > > > > > > > > > > > section for topic/partition
> deletion
> > > > > > lifecycle
> > > > > > > > and
> > > > > > > > > this
> > > > > > > > > > > > > scenario
> > > > > > > > > > > > > > > > > will be
> > > > > > > > > > > > > > > > > > > > > addressed.
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > 601. Unclean leader election
> > > > > > > > > > > > > > > > > > > > > 601.1 Scenario 1: new empty
> follower
> > > > > > > > > > > > > > > > > > > > > After step 1, the follower
> restores up
> > > to
> > > > > > offset
> > > > > > > > > 3. So
> > > > > > > > > > > why
> > > > > > > > > > > > > does
> > > > > > > > > > > > > > > > it
> > > > > > > > > > > > > > > > > have
> > > > > > > > > > > > > > > > > > > > > LE-2 <
> > > > > > https://issues.apache.org/jira/browse/LE-2
> > > > > > > > >
> > > > > > > > > at
> > > > > > > > > > > > > offset 5?
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > Nice catch. It was showing the
> leader
> > > > epoch
> > > > > > > > fetched
> > > > > > > > > > > from
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > > > > > storage. It should be shown with
> the
> > > > > > truncated
> > > > > > > > till
> > > > > > > > > > > offset
> > > > > > > > > > > > > 3.
> > > > > > > > > > > > > > > > > Updated the
> > > > > > > > > > > > > > > > > > > > > KIP.
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > 601.2 senario 5: After Step 3,
> leader A
> > > > has
> > > > > > > > > > > inconsistent
> > > > > > > > > > > > > data
> > > > > > > > > > > > > > > > > between its
> > > > > > > > > > > > > > > > > > > > > local and the tiered data. For
> example.
> > > > > > offset 3
> > > > > > > > > has
> > > > > > > > > > > msg 3
> > > > > > > > > > > > > LE-0
> > > > > > > > > > > > > > > > > <
> https://issues.apache.org/jira/browse/LE-0>
> > > > > > locally,
> > > > > > > > > > > > > > > > > > > > > but msg 5 LE-1 <
> > > > > > > > > > > https://issues.apache.org/jira/browse/LE-1>
> > > > > > > > > > > > > in
> > > > > > > > > > > > > > > > > the remote store. While it's ok for the
> unclean
> > > > > > leader
> > > > > > > > > > > > > > > > > > > > > to lose data, it should still
> return
> > > > > > consistent
> > > > > > > > > data,
> > > > > > > > > > > > > whether
> > > > > > > > > > > > > > > > it's
> > > > > > > > > > > > > > > > > from
> > > > > > > > > > > > > > > > > > > > > the local or the remote store.
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > There is no inconsistency here as
> LE-0
> > > > > > > > > > > > > > > > > <
> https://issues.apache.org/jira/browse/LE-0>
> > > > > > offsets are
> > > > > > > > > [0,
> > > > > > > > > > > 4]
> > > > > > > > > > > > > and LE-2
> > > > > > > > > > > > > > > > > <
> https://issues.apache.org/jira/browse/LE-2>:
> > > > > > > > > > > > > > > > > > > > > [5, ]. It will always get the right
> > > > records
> > > > > > for
> > > > > > > > the
> > > > > > > > > > > given
> > > > > > > > > > > > > offset
> > > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > > > leader epoch. In case of remote,
> RSM is
> > > > > > invoked
> > > > > > > > to
> > > > > > > > > get
> > > > > > > > > > > the
> > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > log
> > > > > > > > > > > > > > > > > > > > > segment that contains the given
> offset
> > > > with
> > > > > > the
> > > > > > > > > leader
> > > > > > > > > > > > > epoch.
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > 601.4 It seems that retention is
> based
> > > on
> > > > > > > > > > > > > > > > > > > > >
> listRemoteLogSegments(TopicPartition
> > > > > > > > > topicPartition,
> > > > > > > > > > > long
> > > > > > > > > > > > > > > > > leaderEpoch).
> > > > > > > > > > > > > > > > > > > > > When there is an unclean leader
> > > election,
> > > > > > it's
> > > > > > > > > possible
> > > > > > > > > > > > > for the
> > > > > > > > > > > > > > > > new
> > > > > > > > > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > > > > > > to not to include certain epochs
> in its
> > > > epoch
> > > > > > > > > cache.
> > > > > > > > > > > How
> > > > > > > > > > > > > are
> > > > > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > > > > > segments associated with those
> epochs
> > > > being
> > > > > > > > > cleaned?
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > That is a good point. This leader
> will
> > > > also
> > > > > > > > > cleanup the
> > > > > > > > > > > > > epochs
> > > > > > > > > > > > > > > > > earlier to
> > > > > > > > > > > > > > > > > > > > > its start leader epoch and delete
> those
> > > > > > segments.
> > > > > > > > > It
> > > > > > > > > > > gets
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > earliest
> > > > > > > > > > > > > > > > > > > > > epoch for a partition and starts
> > > deleting
> > > > > > > > segments
> > > > > > > > > from
> > > > > > > > > > > > > that
> > > > > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > > > > > epoch.
> > > > > > > > > > > > > > > > > > > > > We need one more API in RLMM to
> get the
> > > > > > earliest
> > > > > > > > > leader
> > > > > > > > > > > > > epoch.
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > 601.5 The KIP discusses the
> handling of
> > > > > > unclean
> > > > > > > > > leader
> > > > > > > > > > > > > elections
> > > > > > > > > > > > > > > > > for user
> > > > > > > > > > > > > > > > > > > > > topics. What about unclean leader
> > > > elections
> > > > > > on
> > > > > > > > > > > > > > > > > > > > > __remote_log_segment_metadata?
> > > > > > > > > > > > > > > > > > > > > This is the same as other system
> topics
> > > > like
> > > > > > > > > > > > > consumer_offsets,
> > > > > > > > > > > > > > > > > > > > > __transaction_state topics. As
> > > discussed
> > > > in
> > > > > > the
> > > > > > > > > > > meeting,
> > > > > > > > > > > > > we will
> > > > > > > > > > > > > > > > > add the
> > > > > > > > > > > > > > > > > > > > > behavior of
> > > __remote_log_segment_metadata
> > > > > > topic’s
> > > > > > > > > > > unclean
> > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > > > > > > truncation.
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > 602. It would be useful to clarify
> the
> > > > > > > > limitations
> > > > > > > > > in
> > > > > > > > > > > the
> > > > > > > > > > > > > initial
> > > > > > > > > > > > > > > > > > > > release.
> > > > > > > > > > > > > > > > > > > > > The KIP mentions not supporting
> > > compacted
> > > > > > topics.
> > > > > > > > > What
> > > > > > > > > > > > > about JBOD
> > > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > > > changing the configuration of a
> topic
> > > > from
> > > > > > delete
> > > > > > > > > to
> > > > > > > > > > > > > compact
> > > > > > > > > > > > > > > > after
> > > > > > > > > > > > > > > > > > > > remote.
> > > > > > > > > > > > > > > > > > > > > log. storage. enable (
> > > > > > > > > > > http://remote.log.storage.enable/
> > > > > > > > > > > > > ) is
> > > > > > > > > > > > > > > > > enabled?
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > This was updated in the KIP
> earlier.
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > 603. RLM leader tasks:
> > > > > > > > > > > > > > > > > > > > > 603.1"It checks for rolled over
> > > > LogSegments
> > > > > > > > (which
> > > > > > > > > have
> > > > > > > > > > > > > the last
> > > > > > > > > > > > > > > > > message
> > > > > > > > > > > > > > > > > > > > > offset less than last stable
> offset of
> > > > that
> > > > > > topic
> > > > > > > > > > > > > partition) and
> > > > > > > > > > > > > > > > > copies
> > > > > > > > > > > > > > > > > > > > > them along with their
> > > > offset/time/transaction
> > > > > > > > > indexes
> > > > > > > > > > > and
> > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > > epoch
> > > > > > > > > > > > > > > > > > > > > cache to the remote tier." It
> needs to
> > > > copy
> > > > > > the
> > > > > > > > > > > producer
> > > > > > > > > > > > > snapshot
> > > > > > > > > > > > > > > > > too.
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > Right. It copies producer
> snapshots too
> > > > as
> > > > > > > > > mentioned in
> > > > > > > > > > > > > > > > > LogSegmentData.
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > 603.2 "Local logs are not cleaned
> up
> > > till
> > > > > > those
> > > > > > > > > > > segments
> > > > > > > > > > > > > are
> > > > > > > > > > > > > > > > copied
> > > > > > > > > > > > > > > > > > > > > successfully to remote even though
> > > their
> > > > > > > > retention
> > > > > > > > > > > > > time/size is
> > > > > > > > > > > > > > > > > reached"
> > > > > > > > > > > > > > > > > > > > > This seems weird. If the tiering
> stops
> > > > > > because
> > > > > > > > the
> > > > > > > > > > > remote
> > > > > > > > > > > > > store
> > > > > > > > > > > > > > > > is
> > > > > > > > > > > > > > > > > not
> > > > > > > > > > > > > > > > > > > > > available, we don't want the local
> data
> > > > to
> > > > > > grow
> > > > > > > > > > > forever.
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > It was clarified in the discussion
> that
> > > > the
> > > > > > > > > comment was
> > > > > > > > > > > > > more
> > > > > > > > > > > > > > > > about
> > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > > > local storage goes beyond the
> > > > log.retention.
> > > > > > The
> > > > > > > > > above
> > > > > > > > > > > > > statement
> > > > > > > > > > > > > > > > > is about
> > > > > > > > > > > > > > > > > > > > > local.log.retention but not for the
> > > > complete
> > > > > > > > > > > > > log.retention. When
> > > > > > > > > > > > > > > > it
> > > > > > > > > > > > > > > > > > > > > reaches the log.retention then it
> will
> > > > > > delete the
> > > > > > > > > local
> > > > > > > > > > > > > logs even
> > > > > > > > > > > > > > > > > though
> > > > > > > > > > > > > > > > > > > > > those are not copied to remote
> storage.
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > 604. "RLM maintains a bounded
> > > > cache(possibly
> > > > > > LRU)
> > > > > > > > > of
> > > > > > > > > > > the
> > > > > > > > > > > > > index
> > > > > > > > > > > > > > > > > files of
> > > > > > > > > > > > > > > > > > > > > remote log segments to avoid
> multiple
> > > > index
> > > > > > > > fetches
> > > > > > > > > > > from
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > > > > > storage. These indexes can be used
> in
> > > the
> > > > > > same
> > > > > > > > way
> > > > > > > > > as
> > > > > > > > > > > local
> > > > > > > > > > > > > > > > segment
> > > > > > > > > > > > > > > > > > > > > indexes are used." Could you
> provide
> > > more
> > > > > > details
> > > > > > > > > on
> > > > > > > > > > > this?
> > > > > > > > > > > > > Are
> > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > > indexes
> > > > > > > > > > > > > > > > > > > > > cached in memory or on disk? If on
> > > disk,
> > > > > > where
> > > > > > > > are
> > > > > > > > > they
> > > > > > > > > > > > > stored?
> > > > > > > > > > > > > > > > > Are the
> > > > > > > > > > > > > > > > > > > > > cached indexes bound by a certain
> size?
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > These are cached on disk and
> stored in
> > > > > > log.dir
> > > > > > > > > with a
> > > > > > > > > > > name
> > > > > > > > > > > > > > > > > > > > > “__remote_log_index_cache”. They
> are
> > > > bound
> > > > > > by the
> > > > > > > > > total
> > > > > > > > > > > > > size.
> > > > > > > > > > > > > > > > This
> > > > > > > > > > > > > > > > > will
> > > > > > > > > > > > > > > > > > > > be
> > > > > > > > > > > > > > > > > > > > > exposed as a user configuration,
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > 605. BuildingRemoteLogAux
> > > > > > > > > > > > > > > > > > > > > 605.1 In this section, two options
> are
> > > > > > listed.
> > > > > > > > > Which
> > > > > > > > > > > one is
> > > > > > > > > > > > > > > > chosen?
> > > > > > > > > > > > > > > > > > > > > Option-2, updated the KIP.
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > 605.2 In option 2, it says "Build
> the
> > > > local
> > > > > > > > leader
> > > > > > > > > > > epoch
> > > > > > > > > > > > > cache by
> > > > > > > > > > > > > > > > > cutting
> > > > > > > > > > > > > > > > > > > > > the leader epoch sequence received
> from
> > > > > > remote
> > > > > > > > > storage
> > > > > > > > > > > to
> > > > > > > > > > > > > [LSO,
> > > > > > > > > > > > > > > > > ELO].
> > > > > > > > > > > > > > > > > > > > (LSO
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > = log start offset)." We need to
> do the
> > > > same
> > > > > > > > thing
> > > > > > > > > for
> > > > > > > > > > > the
> > > > > > > > > > > > > > > > producer
> > > > > > > > > > > > > > > > > > > > > snapshot. However, it's hard to
> cut the
> > > > > > producer
> > > > > > > > > > > snapshot
> > > > > > > > > > > > > to an
> > > > > > > > > > > > > > > > > earlier
> > > > > > > > > > > > > > > > > > > > > offset. Another option is to simply
> > > take
> > > > the
> > > > > > > > > lastOffset
> > > > > > > > > > > > > from the
> > > > > > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > > > > > segment and use that as the
> starting
> > > > fetch
> > > > > > offset
> > > > > > > > > in
> > > > > > > > > > > the
> > > > > > > > > > > > > > > > follower.
> > > > > > > > > > > > > > > > > This
> > > > > > > > > > > > > > > > > > > > > avoids the need for cutting.
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > Right, this was mentioned in the
> > > > > > “transactional
> > > > > > > > > > > support”
> > > > > > > > > > > > > section
> > > > > > > > > > > > > > > > > about
> > > > > > > > > > > > > > > > > > > > > adding these details.
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > 606. ListOffsets: Since we need a
> > > version
> > > > > > bump,
> > > > > > > > > could
> > > > > > > > > > > you
> > > > > > > > > > > > > > > > document
> > > > > > > > > > > > > > > > > it
> > > > > > > > > > > > > > > > > > > > > under a protocol change section?
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > Sure, we will update the KIP.
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > 607. "LogStartOffset of a topic can
> > > > point to
> > > > > > > > > either of
> > > > > > > > > > > > > local
> > > > > > > > > > > > > > > > > segment or
> > > > > > > > > > > > > > > > > > > > > remote segment but it is
> initialised
> > > and
> > > > > > > > > maintained in
> > > > > > > > > > > the
> > > > > > > > > > > > > Log
> > > > > > > > > > > > > > > > > class like
> > > > > > > > > > > > > > > > > > > > > now. This is already maintained in
> > > `Log`
> > > > > > class
> > > > > > > > > while
> > > > > > > > > > > > > loading the
> > > > > > > > > > > > > > > > > logs and
> > > > > > > > > > > > > > > > > > > > > it can also be fetched from
> > > > > > > > > RemoteLogMetadataManager."
> > > > > > > > > > > > > What will
> > > > > > > > > > > > > > > > > happen
> > > > > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > > > > the existing logic (e.g. log
> recovery)
> > > > that
> > > > > > > > > currently
> > > > > > > > > > > > > depends on
> > > > > > > > > > > > > > > > > > > > > logStartOffset but assumes it's
> local?
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > They use a field called
> > > > localLogStartOffset
> > > > > > which
> > > > > > > > > is
> > > > > > > > > > > the
> > > > > > > > > > > > > local
> > > > > > > > > > > > > > > > log
> > > > > > > > > > > > > > > > > start
> > > > > > > > > > > > > > > > > > > > > offset..
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > 608. Handle expired remote
> segment: How
> > > > does
> > > > > > it
> > > > > > > > > pick
> > > > > > > > > > > up new
> > > > > > > > > > > > > > > > > > > > logStartOffset
> > > > > > > > > > > > > > > > > > > > > from deleteRecords?
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > Good point. This was not addressed
> in
> > > the
> > > > > > KIP.
> > > > > > > > Will
> > > > > > > > > > > update
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > KIP
> > > > > > > > > > > > > > > > > on how
> > > > > > > > > > > > > > > > > > > > > the RLM task handles this scenario.
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > 609. RLMM message format:
> > > > > > > > > > > > > > > > > > > > > 609.1 It includes both
> MaxTimestamp and
> > > > > > > > > EventTimestamp.
> > > > > > > > > > > > > Where
> > > > > > > > > > > > > > > > does
> > > > > > > > > > > > > > > > > it get
> > > > > > > > > > > > > > > > > > > > > both since the message in the log
> only
> > > > > > contains
> > > > > > > > one
> > > > > > > > > > > > > timestamp?
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > `EventTimeStamp` is the timestamp
> at
> > > > which
> > > > > > that
> > > > > > > > > segment
> > > > > > > > > > > > > metadata
> > > > > > > > > > > > > > > > > event is
> > > > > > > > > > > > > > > > > > > > > generated. This is more for audits.
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > 609.2 If we change just the state
> (e.g.
> > > > to
> > > > > > > > > > > > > DELETE_STARTED), it
> > > > > > > > > > > > > > > > > seems it's
> > > > > > > > > > > > > > > > > > > > > wasteful to have to include all
> other
> > > > fields
> > > > > > not
> > > > > > > > > > > changed.
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > This is a good point. We thought
> about
> > > > > > > > incremental
> > > > > > > > > > > > > updates. But
> > > > > > > > > > > > > > > > we
> > > > > > > > > > > > > > > > > want
> > > > > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > > > > make sure all the events are in the
> > > > expected
> > > > > > > > order
> > > > > > > > > and
> > > > > > > > > > > take
> > > > > > > > > > > > > > > > action
> > > > > > > > > > > > > > > > > based
> > > > > > > > > > > > > > > > > > > > > on the latest event. Will think
> through
> > > > the
> > > > > > > > > approaches
> > > > > > > > > > > in
> > > > > > > > > > > > > detail
> > > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > > > update here.
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > 609.3 Could you document which
> process
> > > > makes
> > > > > > the
> > > > > > > > > > > following
> > > > > > > > > > > > > > > > > transitions
> > > > > > > > > > > > > > > > > > > > > DELETE_MARKED, DELETE_STARTED,
> > > > > > DELETE_FINISHED?
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > Okay, will document more details.
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > 610.
> > > remote.log.reader.max.pending.tasks:
> > > > > > > > "Maximum
> > > > > > > > > > > remote
> > > > > > > > > > > > > log
> > > > > > > > > > > > > > > > > reader
> > > > > > > > > > > > > > > > > > > > > thread pool task queue size. If the
> > > task
> > > > > > queue is
> > > > > > > > > full,
> > > > > > > > > > > > > broker
> > > > > > > > > > > > > > > > > will stop
> > > > > > > > > > > > > > > > > > > > > reading remote log segments." What
> does
> > > > the
> > > > > > > > broker
> > > > > > > > > do
> > > > > > > > > > > if
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > queue
> > > > > > > > > > > > > > > > > is
> > > > > > > > > > > > > > > > > > > > > full?
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > It returns an error for this topic
> > > > partition.
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > 611. What do we return if the
> request
> > > > > > > > offset/epoch
> > > > > > > > > > > doesn't
> > > > > > > > > > > > > exist
> > > > > > > > > > > > > > > > > in the
> > > > > > > > > > > > > > > > > > > > > following API?
> > > > > > > > > > > > > > > > > > > > > RemoteLogSegmentMetadata
> > > > > > > > > > > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > > > > > > > > > > > > > topicPartition, long offset, int
> > > > > > epochForOffset)
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > This returns null. But we prefer to
> > > > update
> > > > > > the
> > > > > > > > > return
> > > > > > > > > > > type
> > > > > > > > > > > > > as
> > > > > > > > > > > > > > > > > Optional
> > > > > > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > > > return Empty if that does not
> exist.
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > > > > > > Satish.
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > On Tue, Sep 1, 2020 at 9:45 AM Jun
> Rao
> > > <
> > > > jun@
> > > > > > > > > > > confluent.
> > > > > > > > > > > > > io (
> > > > > > > > > > > > > > > > > > > > > jun@confluent.io ) > wrote:
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >> Hi, Satish,
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >> Thanks for the updated KIP. Made
> > > another
> > > > > > pass. A
> > > > > > > > > few
> > > > > > > > > > > more
> > > > > > > > > > > > > > > > comments
> > > > > > > > > > > > > > > > > > > > below.
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >> 600. The topic deletion logic
> needs
> > > more
> > > > > > > > details.
> > > > > > > > > > > > > > > > > > > > >> 600.1 The KIP mentions "The
> controller
> > > > > > considers
> > > > > > > > > the
> > > > > > > > > > > topic
> > > > > > > > > > > > > > > > > partition is
> > > > > > > > > > > > > > > > > > > > >> deleted only when it determines
> that
> > > > there
> > > > > > are
> > > > > > > > no
> > > > > > > > > log
> > > > > > > > > > > > > segments
> > > > > > > > > > > > > > > > > for that
> > > > > > > > > > > > > > > > > > > > >> topic partition by using RLMM".
> How is
> > > > this
> > > > > > > > done?
> > > > > > > > > > > 600.2
> > > > > > > > > > > > > "If the
> > > > > > > > > > > > > > > > > delete
> > > > > > > > > > > > > > > > > > > > >> option is enabled then the leader
> will
> > > > stop
> > > > > > RLM
> > > > > > > > > task
> > > > > > > > > > > and
> > > > > > > > > > > > > stop
> > > > > > > > > > > > > > > > > processing
> > > > > > > > > > > > > > > > > > > > >> and it sets all the remote log
> segment
> > > > > > metadata
> > > > > > > > of
> > > > > > > > > > > that
> > > > > > > > > > > > > > > > partition
> > > > > > > > > > > > > > > > > with a
> > > > > > > > > > > > > > > > > > > > >> delete marker and publishes them
> to
> > > > RLMM."
> > > > > > We
> > > > > > > > > > > discussed
> > > > > > > > > > > > > this
> > > > > > > > > > > > > > > > > earlier.
> > > > > > > > > > > > > > > > > > > > When
> > > > > > > > > > > > > > > > > > > > >> a topic is being deleted, there
> may
> > > not
> > > > be a
> > > > > > > > > leader
> > > > > > > > > > > for
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > deleted
> > > > > > > > > > > > > > > > > > > > >> partition.
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >> 601. Unclean leader election
> > > > > > > > > > > > > > > > > > > > >> 601.1 Scenario 1: new empty
> follower
> > > > > > > > > > > > > > > > > > > > >> After step 1, the follower
> restores up
> > > > to
> > > > > > offset
> > > > > > > > > 3. So
> > > > > > > > > > > > > why does
> > > > > > > > > > > > > > > > > it have
> > > > > > > > > > > > > > > > > > > > >> LE-2 <
> > > > > > > > https://issues.apache.org/jira/browse/LE-2>
> > > > > > > > > at
> > > > > > > > > > > > > offset 5?
> > > > > > > > > > > > > > > > > > > > >> 601.2 senario 5: After Step 3,
> leader
> > > A
> > > > has
> > > > > > > > > > > inconsistent
> > > > > > > > > > > > > data
> > > > > > > > > > > > > > > > > between
> > > > > > > > > > > > > > > > > > > > its
> > > > > > > > > > > > > > > > > > > > >> local and the tiered data. For
> > > example.
> > > > > > offset 3
> > > > > > > > > has
> > > > > > > > > > > msg
> > > > > > > > > > > > > 3 LE-0
> > > > > > > > > > > > > > > > > <
> https://issues.apache.org/jira/browse/LE-0>
> > > > > > locally,
> > > > > > > > > > > > > > > > > > > > >> but msg 5 LE-1 <
> > > > > > > > > > > > > https://issues.apache.org/jira/browse/LE-1> in
> > > > > > > > > > > > > > > > > the remote store. While it's ok for the
> unclean
> > > > > > leader
> > > > > > > > > > > > > > > > > > > > >> to lose data, it should still
> return
> > > > > > consistent
> > > > > > > > > data,
> > > > > > > > > > > > > whether
> > > > > > > > > > > > > > > > > it's from
> > > > > > > > > > > > > > > > > > > > >> the local or the remote store.
> > > > > > > > > > > > > > > > > > > > >> 601.3 The follower picks up log
> start
> > > > offset
> > > > > > > > > using the
> > > > > > > > > > > > > following
> > > > > > > > > > > > > > > > > api.
> > > > > > > > > > > > > > > > > > > > >> Suppose that we have 3 remote
> segments
> > > > (LE,
> > > > > > > > > > > > > SegmentStartOffset)
> > > > > > > > > > > > > > > > > as (2,
> > > > > > > > > > > > > > > > > > > > >> 10),
> > > > > > > > > > > > > > > > > > > > >> (3, 20) and (7, 15) due to an
> unclean
> > > > leader
> > > > > > > > > election.
> > > > > > > > > > > > > Using the
> > > > > > > > > > > > > > > > > > > > following
> > > > > > > > > > > > > > > > > > > > >> api will cause logStartOffset to
> go
> > > > backward
> > > > > > > > from
> > > > > > > > > 20
> > > > > > > > > > > to
> > > > > > > > > > > > > 15. How
> > > > > > > > > > > > > > > > > do we
> > > > > > > > > > > > > > > > > > > > >> prevent that?
> > > > > > > > > > > > > > > > > > > > >> earliestLogOffset(TopicPartition
> > > > > > topicPartition,
> > > > > > > > > int
> > > > > > > > > > > > > > > > leaderEpoch)
> > > > > > > > > > > > > > > > > 601.4
> > > > > > > > > > > > > > > > > > > > It
> > > > > > > > > > > > > > > > > > > > >> seems that retention is based on
> > > > > > > > > > > > > > > > > > > > >>
> listRemoteLogSegments(TopicPartition
> > > > > > > > > topicPartition,
> > > > > > > > > > > long
> > > > > > > > > > > > > > > > > leaderEpoch).
> > > > > > > > > > > > > > > > > > > > >> When there is an unclean leader
> > > > election,
> > > > > > it's
> > > > > > > > > > > possible
> > > > > > > > > > > > > for the
> > > > > > > > > > > > > > > > > new
> > > > > > > > > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > > > > > >> to not to include certain epochs
> in
> > > its
> > > > > > epoch
> > > > > > > > > cache.
> > > > > > > > > > > How
> > > > > > > > > > > > > are
> > > > > > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > > > > >> segments associated with those
> epochs
> > > > being
> > > > > > > > > cleaned?
> > > > > > > > > > > > > 601.5 The
> > > > > > > > > > > > > > > > KIP
> > > > > > > > > > > > > > > > > > > > >> discusses the handling of unclean
> > > leader
> > > > > > > > > elections for
> > > > > > > > > > > > > user
> > > > > > > > > > > > > > > > > topics. What
> > > > > > > > > > > > > > > > > > > > >> about unclean leader elections on
> > > > > > > > > > > > > > > > > > > > >> __remote_log_segment_metadata?
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >> 602. It would be useful to
> clarify the
> > > > > > > > > limitations in
> > > > > > > > > > > the
> > > > > > > > > > > > > > > > initial
> > > > > > > > > > > > > > > > > > > > release.
> > > > > > > > > > > > > > > > > > > > >> The KIP mentions not supporting
> > > > compacted
> > > > > > > > topics.
> > > > > > > > > What
> > > > > > > > > > > > > about
> > > > > > > > > > > > > > > > JBOD
> > > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > > >> changing the configuration of a
> topic
> > > > from
> > > > > > > > delete
> > > > > > > > > to
> > > > > > > > > > > > > compact
> > > > > > > > > > > > > > > > after
> > > > > > > > > > > > > > > > > > > > remote.
> > > > > > > > > > > > > > > > > > > > >> log. storage. enable (
> > > > > > > > > > > http://remote.log.storage.enable/
> > > > > > > > > > > > > ) is
> > > > > > > > > > > > > > > > > enabled?
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >> 603. RLM leader tasks:
> > > > > > > > > > > > > > > > > > > > >> 603.1"It checks for rolled over
> > > > LogSegments
> > > > > > > > (which
> > > > > > > > > > > have
> > > > > > > > > > > > > the last
> > > > > > > > > > > > > > > > > message
> > > > > > > > > > > > > > > > > > > > >> offset less than last stable
> offset of
> > > > that
> > > > > > > > topic
> > > > > > > > > > > > > partition) and
> > > > > > > > > > > > > > > > > copies
> > > > > > > > > > > > > > > > > > > > >> them along with their
> > > > > > offset/time/transaction
> > > > > > > > > indexes
> > > > > > > > > > > and
> > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > > epoch
> > > > > > > > > > > > > > > > > > > > >> cache to the remote tier." It
> needs to
> > > > copy
> > > > > > the
> > > > > > > > > > > producer
> > > > > > > > > > > > > > > > snapshot
> > > > > > > > > > > > > > > > > too.
> > > > > > > > > > > > > > > > > > > > >> 603.2 "Local logs are not cleaned
> up
> > > > till
> > > > > > those
> > > > > > > > > > > segments
> > > > > > > > > > > > > are
> > > > > > > > > > > > > > > > > copied
> > > > > > > > > > > > > > > > > > > > >> successfully to remote even though
> > > their
> > > > > > > > retention
> > > > > > > > > > > > > time/size is
> > > > > > > > > > > > > > > > > reached"
> > > > > > > > > > > > > > > > > > > > >> This seems weird. If the tiering
> stops
> > > > > > because
> > > > > > > > the
> > > > > > > > > > > remote
> > > > > > > > > > > > > store
> > > > > > > > > > > > > > > > > is not
> > > > > > > > > > > > > > > > > > > > >> available, we don't want the local
> > > data
> > > > to
> > > > > > grow
> > > > > > > > > > > forever.
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >> 604. "RLM maintains a bounded
> > > > cache(possibly
> > > > > > > > LRU)
> > > > > > > > > of
> > > > > > > > > > > the
> > > > > > > > > > > > > index
> > > > > > > > > > > > > > > > > files of
> > > > > > > > > > > > > > > > > > > > >> remote log segments to avoid
> multiple
> > > > index
> > > > > > > > > fetches
> > > > > > > > > > > from
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > > > > >> storage. These indexes can be
> used in
> > > > the
> > > > > > same
> > > > > > > > > way as
> > > > > > > > > > > > > local
> > > > > > > > > > > > > > > > > segment
> > > > > > > > > > > > > > > > > > > > >> indexes are used." Could you
> provide
> > > > more
> > > > > > > > details
> > > > > > > > > on
> > > > > > > > > > > > > this? Are
> > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > > indexes
> > > > > > > > > > > > > > > > > > > > >> cached in memory or on disk? If on
> > > disk,
> > > > > > where
> > > > > > > > are
> > > > > > > > > > > they
> > > > > > > > > > > > > stored?
> > > > > > > > > > > > > > > > > Are the
> > > > > > > > > > > > > > > > > > > > >> cached indexes bound by a certain
> > > size?
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >> 605. BuildingRemoteLogAux
> > > > > > > > > > > > > > > > > > > > >> 605.1 In this section, two
> options are
> > > > > > listed.
> > > > > > > > > Which
> > > > > > > > > > > one
> > > > > > > > > > > > > is
> > > > > > > > > > > > > > > > > chosen?
> > > > > > > > > > > > > > > > > > > > 605.2
> > > > > > > > > > > > > > > > > > > > >> In option 2, it says "Build the
> local
> > > > leader
> > > > > > > > epoch
> > > > > > > > > > > cache
> > > > > > > > > > > > > by
> > > > > > > > > > > > > > > > > cutting the
> > > > > > > > > > > > > > > > > > > > >> leader epoch sequence received
> from
> > > > remote
> > > > > > > > > storage to
> > > > > > > > > > > > > [LSO,
> > > > > > > > > > > > > > > > ELO].
> > > > > > > > > > > > > > > > > (LSO
> > > > > > > > > > > > > > > > > > > > >> = log start offset)." We need to
> do
> > > the
> > > > same
> > > > > > > > thing
> > > > > > > > > > > for the
> > > > > > > > > > > > > > > > > producer
> > > > > > > > > > > > > > > > > > > > >> snapshot. However, it's hard to
> cut
> > > the
> > > > > > producer
> > > > > > > > > > > snapshot
> > > > > > > > > > > > > to an
> > > > > > > > > > > > > > > > > earlier
> > > > > > > > > > > > > > > > > > > > >> offset. Another option is to
> simply
> > > > take the
> > > > > > > > > > > lastOffset
> > > > > > > > > > > > > from the
> > > > > > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > > > > >> segment and use that as the
> starting
> > > > fetch
> > > > > > > > offset
> > > > > > > > > in
> > > > > > > > > > > the
> > > > > > > > > > > > > > > > > follower. This
> > > > > > > > > > > > > > > > > > > > >> avoids the need for cutting.
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >> 606. ListOffsets: Since we need a
> > > > version
> > > > > > bump,
> > > > > > > > > could
> > > > > > > > > > > you
> > > > > > > > > > > > > > > > > document it
> > > > > > > > > > > > > > > > > > > > >> under a protocol change section?
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >> 607. "LogStartOffset of a topic
> can
> > > > point to
> > > > > > > > > either of
> > > > > > > > > > > > > local
> > > > > > > > > > > > > > > > > segment or
> > > > > > > > > > > > > > > > > > > > >> remote segment but it is
> initialised
> > > and
> > > > > > > > > maintained in
> > > > > > > > > > > > > the Log
> > > > > > > > > > > > > > > > > class
> > > > > > > > > > > > > > > > > > > > like
> > > > > > > > > > > > > > > > > > > > >> now. This is already maintained in
> > > `Log`
> > > > > > class
> > > > > > > > > while
> > > > > > > > > > > > > loading the
> > > > > > > > > > > > > > > > > logs
> > > > > > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > > >> it can also be fetched from
> > > > > > > > > RemoteLogMetadataManager."
> > > > > > > > > > > > > What will
> > > > > > > > > > > > > > > > > happen
> > > > > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > > > >> the existing logic (e.g. log
> recovery)
> > > > that
> > > > > > > > > currently
> > > > > > > > > > > > > depends on
> > > > > > > > > > > > > > > > > > > > >> logStartOffset but assumes it's
> local?
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >> 608. Handle expired remote
> segment:
> > > How
> > > > > > does it
> > > > > > > > > pick
> > > > > > > > > > > up
> > > > > > > > > > > > > new
> > > > > > > > > > > > > > > > > > > > logStartOffset
> > > > > > > > > > > > > > > > > > > > >> from deleteRecords?
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >> 609. RLMM message format:
> > > > > > > > > > > > > > > > > > > > >> 609.1 It includes both
> MaxTimestamp
> > > and
> > > > > > > > > > > EventTimestamp.
> > > > > > > > > > > > > Where
> > > > > > > > > > > > > > > > > does it
> > > > > > > > > > > > > > > > > > > > get
> > > > > > > > > > > > > > > > > > > > >> both since the message in the log
> only
> > > > > > contains
> > > > > > > > > one
> > > > > > > > > > > > > timestamp?
> > > > > > > > > > > > > > > > > 609.2 If
> > > > > > > > > > > > > > > > > > > > we
> > > > > > > > > > > > > > > > > > > > >> change just the state (e.g. to
> > > > > > DELETE_STARTED),
> > > > > > > > it
> > > > > > > > > > > seems
> > > > > > > > > > > > > it's
> > > > > > > > > > > > > > > > > wasteful
> > > > > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > > > >> have to include all other fields
> not
> > > > > > changed.
> > > > > > > > > 609.3
> > > > > > > > > > > Could
> > > > > > > > > > > > > you
> > > > > > > > > > > > > > > > > document
> > > > > > > > > > > > > > > > > > > > >> which process makes the following
> > > > > > transitions
> > > > > > > > > > > > > DELETE_MARKED,
> > > > > > > > > > > > > > > > > > > > >> DELETE_STARTED, DELETE_FINISHED?
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >> 610.
> > > > remote.log.reader.max.pending.tasks:
> > > > > > > > "Maximum
> > > > > > > > > > > remote
> > > > > > > > > > > > > log
> > > > > > > > > > > > > > > > > reader
> > > > > > > > > > > > > > > > > > > > >> thread pool task queue size. If
> the
> > > task
> > > > > > queue
> > > > > > > > is
> > > > > > > > > > > full,
> > > > > > > > > > > > > broker
> > > > > > > > > > > > > > > > > will stop
> > > > > > > > > > > > > > > > > > > > >> reading remote log segments." What
> > > does
> > > > the
> > > > > > > > > broker do
> > > > > > > > > > > if
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > queue is
> > > > > > > > > > > > > > > > > > > > >> full?
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >> 611. What do we return if the
> request
> > > > > > > > offset/epoch
> > > > > > > > > > > > > doesn't exist
> > > > > > > > > > > > > > > > > in the
> > > > > > > > > > > > > > > > > > > > >> following API?
> > > > > > > > > > > > > > > > > > > > >> RemoteLogSegmentMetadata
> > > > > > > > > > > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > > > > > > > > > > > > >> topicPartition, long offset, int
> > > > > > epochForOffset)
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >> Jun
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >> On Mon, Aug 31, 2020 at 11:19 AM
> > > Satish
> > > > > > Duggana
> > > > > > > > <
> > > > > > > > > > > satish.
> > > > > > > > > > > > > > > > duggana@
> > > > > > > > > > > > > > > > > > > > gmail. com
> > > > > > > > > > > > > > > > > > > > >> ( satish.duggana@gmail.com ) >
> wrote:
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>> KIP is updated with
> > > > > > > > > > > > > > > > > > > > >>> - Remote log segment metadata
> topic
> > > > message
> > > > > > > > > > > > > format/schema.
> > > > > > > > > > > > > > > > > > > > >>> - Added remote log segment
> metadata
> > > > state
> > > > > > > > > > > transitions and
> > > > > > > > > > > > > > > > > explained how
> > > > > > > > > > > > > > > > > > > > >>> the deletion of segments is
> handled,
> > > > > > including
> > > > > > > > > the
> > > > > > > > > > > case
> > > > > > > > > > > > > of
> > > > > > > > > > > > > > > > > partition
> > > > > > > > > > > > > > > > > > > > >>> deletions.
> > > > > > > > > > > > > > > > > > > > >>> - Added a few more limitations
> in the
> > > > "Non
> > > > > > > > goals"
> > > > > > > > > > > > > section.
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>> Thanks,
> > > > > > > > > > > > > > > > > > > > >>> Satish.
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>> On Thu, Aug 27, 2020 at 12:42 AM
> > > > Harsha Ch
> > > > > > <
> > > > > > > > > harsha.
> > > > > > > > > > > ch@
> > > > > > > > > > > > > > > > gmail.
> > > > > > > > > > > > > > > > > com (
> > > > > > > > > > > > > > > > > > > > >>> harsha.ch@gmail.com ) > wrote:
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > >>>> Updated the KIP with Meeting
> Notes
> > > > section
> > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>> https:/ / cwiki. apache. org/
> > > > confluence/
> > > > > > > > > display/
> > > > > > > > > > > KAFKA/
> > > > > > > > > > > > > > > > > > > > KIP-405 <
> > > > > > > > > https://issues.apache.org/jira/browse/KIP-405>
> > > > > > > > > > > > > > > > >
> > > > > > > > >
> %3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> > > > > > > > > > > > > > > > > > > > >>> (
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > >
> > > >
> > >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-405%3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> > > > > > > > > > > > > > > > > > > > >>> )
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > >>>> On Tue, Aug 25, 2020 at 1:03 PM
> Jun
> > > > Rao <
> > > > > > jun@
> > > > > > > > > > > > > confluent. io
> > > > > > > > > > > > > > > > (
> > > > > > > > > > > > > > > > > > > > >>>> jun@confluent.io ) > wrote:
> > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > >>>>
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> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>> Hi, Harsha,
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>> Thanks for the summary. Could
> you
> > > > add the
> > > > > > > > > summary
> > > > > > > > > > > and
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > recording
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>> link to
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>> the last section of
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>
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> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>> https:/ / cwiki. apache. org/
> > > > confluence/
> > > > > > > > > display/
> > > > > > > > > > > KAFKA/
> > > > > > > > > > > > > > > > > > > > Kafka+Improvement+Proposals
> > > > > > > > > > > > > > > > > > > > >>> (
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >
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> > > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > >
> > > >
> > >
> https://cwiki.apache.org/confluence/display/KAFKA/Kafka+Improvement+Proposals
> > > > > > > > > > > > > > > > > > > > >>> )
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
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> > > > > > > > > > > > > > > > > > > > >>>>> ?
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>> Jun
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>> On Tue, Aug 25, 2020 at 11:12
> AM
> > > > Harsha
> > > > > > > > > > > Chintalapani <
> > > > > > > > > > > > > kafka@
> > > > > > > > > > > > > > > > > > > > harsha. io (
> > > > > > > > > > > > > > > > > > > > >>>>> kafka@harsha.io ) > wrote:
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>> Thanks everyone for attending
> the
> > > > > > meeting
> > > > > > > > > today.
> > > > > > > > > > > > > > > > > > > > >>>>>> Here is the recording
> > > > > > > > > > > > > > > > > > > > >>>>>>
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> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>> https:/ / drive. google. com/
> file/
> > > d/
> > > > > > > > > > > > > > > > > > > > 14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/
> > > > > > view?usp=sharing
> > > > > > > > > > > > > > > > > > > > >>> (
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > >
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> > > > > > > >
> > > > > >
> > > >
> > >
> https://drive.google.com/file/d/14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/view?usp=sharing
> > > > > > > > > > > > > > > > > > > > >>> )
> > > > > > > > > > > > > > > > > > > > >>>
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> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>> Notes:
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>> 1. KIP is updated with
> follower
> > > > fetch
> > > > > > > > > protocol and
> > > > > > > > > > > > > ready to
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>> reviewed
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>> 2. Satish to capture schema of
> > > > internal
> > > > > > > > > metadata
> > > > > > > > > > > > > topic in
> > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > KIP
> > > > > > > > > > > > > > > > > > > > >>>>>> 3. We will update the KIP with
> > > > details
> > > > > > of
> > > > > > > > > > > different
> > > > > > > > > > > > > cases
> > > > > > > > > > > > > > > > > > > > >>>>>> 4. Test plan will be captured
> in a
> > > > doc
> > > > > > and
> > > > > > > > > will
> > > > > > > > > > > add
> > > > > > > > > > > > > to the
> > > > > > > > > > > > > > > > KIP
> > > > > > > > > > > > > > > > > > > > >>>>>> 5. Add a section
> "Limitations" to
> > > > > > capture
> > > > > > > > the
> > > > > > > > > > > > > capabilities
> > > > > > > > > > > > > > > > > that
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>> will
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>> be
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>> introduced with this KIP and
> what
> > > > will
> > > > > > not
> > > > > > > > be
> > > > > > > > > > > covered
> > > > > > > > > > > > > in
> > > > > > > > > > > > > > > > this
> > > > > > > > > > > > > > > > > KIP.
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>> Please add to it I missed
> > > anything.
> > > > Will
> > > > > > > > > produce a
> > > > > > > > > > > > > formal
> > > > > > > > > > > > > > > > > meeting
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
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> > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>> notes
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>> from next meeting onwards.
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>> Thanks,
> > > > > > > > > > > > > > > > > > > > >>>>>> Harsha
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>> On Mon, Aug 24, 2020 at 9:42
> PM,
> > > > Ying
> > > > > > Zheng
> > > > > > > > <
> > > > > > > > > > > yingz@
> > > > > > > > > > > > > uber.
> > > > > > > > > > > > > > > > > com.
> > > > > > > > > > > > > > > > > > > > invalid (
> > > > > > > > > > > > > > > > > > > > >>>>>> yingz@uber.com.invalid ) >
> wrote:
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> We did some basic feature
> tests
> > > at
> > > > > > Uber.
> > > > > > > > The
> > > > > > > > > test
> > > > > > > > > > > > > cases and
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
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> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
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> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>> results are
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>>
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> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> shared in this google doc:
> > > > > > > > > > > > > > > > > > > > >>>>>>> https:/ / docs. google. com/
> > > > > > spreadsheets/
> > > > > > > > > d/ (
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > https://docs.google.com/spreadsheets/d/ )
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >
> > > > > > > > 1XhNJqjzwXvMCcAOhEH0sSXU6RTvyoSf93DHF-YMfGLk/edit?usp=sharing
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> The performance test results
> were
> > > > > > already
> > > > > > > > > shared
> > > > > > > > > > > in
> > > > > > > > > > > > > the KIP
> > > > > > > > > > > > > > > > > last
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
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> > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>> month.
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> On Mon, Aug 24, 2020 at
> 11:10 AM
> > > > > > Harsha Ch
> > > > > > > > <
> > > > > > > > > > > harsha.
> > > > > > > > > > > > > ch@
> > > > > > > > > > > > > > > > > gmail.
> > > > > > > > > > > > > > > > > > > > com (
> > > > > > > > > > > > > > > > > > > > >>>>>>> harsha.ch@gmail.com ) >
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>> wrote:
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> "Understand commitments
> towards
> > > > driving
> > > > > > > > > design &
> > > > > > > > > > > > > > > > > implementation of
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
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> > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>> the
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>> KIP
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> further and how it aligns
> with
> > > > > > participant
> > > > > > > > > > > interests
> > > > > > > > > > > > > in
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>> contributing to
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>> the
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> efforts (ex: in the context
> of
> > > > Uber’s
> > > > > > Q3/Q4
> > > > > > > > > > > > > roadmap)." What
> > > > > > > > > > > > > > > > > is that
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>> about?
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> On Mon, Aug 24, 2020 at
> 11:05 AM
> > > > > > Kowshik
> > > > > > > > > > > Prakasam <
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>> kprakasam@ confluent. io (
> > > > > > > > > kprakasam@confluent.io
> > > > > > > > > > > ) >
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> wrote:
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> Hi Harsha,
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> The following google doc
> > > contains a
> > > > > > > > proposal
> > > > > > > > > for
> > > > > > > > > > > > > temporary
> > > > > > > > > > > > > > > > > agenda
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>> for
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>> the
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> KIP-405 <
> > > > > > > > > > > > > https://issues.apache.org/jira/browse/KIP-405> <
> > > > > > > > > > > > > > > > > https:/ / issues. apache. org/ jira/
> browse/
> > > > KIP-405
> > > > > > > > > > > > > > > > > <
> https://issues.apache.org/jira/browse/KIP-405
> > > >
> > > > (
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > https://issues.apache.org/jira/browse/KIP-405 )
> > > > > > > > > > > >
> > > > > > > > > > > > > sync
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>> meeting
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> tomorrow:
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> https:/ / docs. google. com/
> > > > document/
> > > > > > d/ (
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > https://docs.google.com/document/d/ )
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > 1pqo8X5LU8TpwfC_iqSuVPezhfCfhGkbGN2TqiPA3LBU/edit
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> .
> > > > > > > > > > > > > > > > > > > > >>>>>>> Please could you add it to
> the
> > > > Google
> > > > > > > > > calendar
> > > > > > > > > > > > > invite?
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> Thank you.
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> Cheers,
> > > > > > > > > > > > > > > > > > > > >>>>>>> Kowshik
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> On Thu, Aug 20, 2020 at
> 10:58 AM
> > > > > > Harsha Ch
> > > > > > > > <
> > > > > > > > > > > harsha.
> > > > > > > > > > > > > ch@
> > > > > > > > > > > > > > > > > gmail.
> > > > > > > > > > > > > > > > > > > > com (
> > > > > > > > > > > > > > > > > > > > >>>>>>> harsha.ch@gmail.com ) >
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>> wrote:
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> Hi All,
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> Scheduled a meeting for
> Tuesday
> > > > 9am -
> > > > > > 10am.
> > > > > > > > > I can
> > > > > > > > > > > > > record
> > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>> upload for
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> community to be able to
> follow
> > > the
> > > > > > > > > discussion.
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> Jun, please add the required
> > > folks
> > > > on
> > > > > > > > > confluent
> > > > > > > > > > > side.
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> Thanks,
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> Harsha
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> On Thu, Aug 20, 2020 at
> 12:33 AM,
> > > > > > Alexandre
> > > > > > > > > > > Dupriez <
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>> alexandre.dupriez@
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> gmail. com (
> http://gmail.com/
> > > ) >
> > > > > > wrote:
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> Hi Jun,
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> Many thanks for your
> initiative.
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> If you like, I am happy to
> attend
> > > > at
> > > > > > the
> > > > > > > > > time you
> > > > > > > > > > > > > > > > suggested.
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> Many thanks,
> > > > > > > > > > > > > > > > > > > > >>>>>>> Alexandre
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> Le mer. 19 août 2020 à 22:00,
> > > > Harsha
> > > > > > Ch <
> > > > > > > > > > > harsha. ch@
> > > > > > > > > > > > > > > > > gmail. com (
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>> harsha.
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> ch@ gmail. com (
> ch@gmail.com )
> > > )
> > > > > a
> > > > > > > > écrit
> > > > > > > > > :
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> Hi Jun,
> > > > > > > > > > > > > > > > > > > > >>>>>>> Thanks. This will help a lot.
> > > > Tuesday
> > > > > > will
> > > > > > > > > work
> > > > > > > > > > > for
> > > > > > > > > > > > > us.
> > > > > > > > > > > > > > > > > > > > >>>>>>> -Harsha
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> On Wed, Aug 19, 2020 at 1:24
> PM
> > > Jun
> > > > > > Rao <
> > > > > > > > > jun@
> > > > > > > > > > > > > confluent.
> > > > > > > > > > > > > > > > > io (
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>> jun@
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> confluent. io (
> > > > http://confluent.io/
> > > > > > ) ) >
> > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> Hi, Satish, Ying, Harsha,
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> Do you think it would be
> useful
> > > to
> > > > > > have a
> > > > > > > > > regular
> > > > > > > > > > > > > virtual
> > > > > > > > > > > > > > > > > meeting
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>> to
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> discuss this KIP? The goal
> of the
> > > > > > meeting
> > > > > > > > > will be
> > > > > > > > > > > > > sharing
> > > > > > > > > > > > > > > > > > > > >>>>>>> design/development progress
> and
> > > > > > discussing
> > > > > > > > > any
> > > > > > > > > > > open
> > > > > > > > > > > > > issues
> > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> accelerate
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> this KIP. If so, will every
> > > Tuesday
> > > > > > (from
> > > > > > > > > next
> > > > > > > > > > > week)
> > > > > > > > > > > > > > > > 9am-10am
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> PT
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> work for you? I can help set
> up a
> > > > Zoom
> > > > > > > > > meeting,
> > > > > > > > > > > > > invite
> > > > > > > > > > > > > > > > > everyone who
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> might
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> be interested, have it
> recorded
> > > and
> > > > > > shared,
> > > > > > > > > etc.
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> Thanks,
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> Jun
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> On Tue, Aug 18, 2020 at
> 11:01 AM
> > > > Satish
> > > > > > > > > Duggana <
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> satish. duggana@ gmail. com
> (
> > > > satish.
> > > > > > > > > duggana@
> > > > > > > > > > > > > gmail. com
> > > > > > > > > > > > > > > > (
> > > > > > > > > > > > > > > > > > > > >>>>>>> satish.duggana@gmail.com )
> ) >
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> wrote:
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> Hi Kowshik,
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> Thanks for looking into the
> KIP
> > > and
> > > > > > sending
> > > > > > > > > your
> > > > > > > > > > > > > comments.
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > > >>>>>>> 5001. Under the section
> "Follower
> > > > fetch
> > > > > > > > > protocol
> > > > > > > > > > > in
> > > > > > > > > > > > > > > > detail",
> > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > > >>>>>>> next-local-offset is the
> offset
> > > > upto
> > > > > > which
> > > > > > > > > the
> > > > > > > > > > > > > segments are
> > > > > > > > > > > > > > > > > copied
> > > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > >
> > > >
> > >
>

Re: [DISCUSS] KIP-405: Kafka Tiered Storage

[Satish Duggana <sa...@gmail.com>]

Hi Manikumar,
Thanks for your comment. Please find the inline replies below.

9201. Can we make it clear by mentioning RLM as an internal component and
RLMM and RSM are pluggable components.
It's also good to update/add the RLM, RLMM components  diagrams with
internal components/tasks.

Updated the KIP.

9202. RLMM metadata topic is a non-compact topic. Can we make clear that
metadata topic retention time should be greater
 than user topics. or How about setting retention set to -1 (unlimited) and
let users to modify it.

I am fine with -1 and updated the configuration doc and made it clear
in the KIP.

9203. RLMM has additional responsibility of handling topic delete requests.
With current design, RLMM implementations need
to implement deletion logic. How about making RemotePartitionRemover as a
separate task, which can be reused..

Good point. We had plans to address that in a future KIP, added in
future work items.

9204. Can we list all the new error codes added by the KIP?

Those are mentioned in the protocol changes section.

9205. Can we also support  `remote.log.metadata.producr.*`,
`remote.log.metadata.consumer.*` prefixed configs to
override any default configs ?. also include RLMM cache configs, if any.

Good point. Updated the KIP.

9206. In the Upgrade section, we have below statement
"Before enabling tiered storage, you should make sure the producer
snapshots are built for all the segments for that topic
in all followers. You should wait till the log retention occurs for all the
segments so that all the segments have producer snapshots."
Can you add more details about this constraint?

Sure, updated in the KIP.


~Satish.

On Tue, 2 Feb 2021 at 21:04, Manikumar <ma...@gmail.com> wrote:
>
> Hi Satish,
>
> Thanks for the KIP.  some of my comments below.
>
> 9201. Can we make it clear by mentioning RLM as an internal component and
> RLMM and RSM are pluggable components.
> It's also good to update/add the RLM, RLMM components  diagrams with
> internal components/tasks.
>
> 9202. RLMM metadata topic is a non-compact topic. Can we make clear that
> metadata topic retention time should be greater
>  than user topics. or How about setting retention set to -1 (unlimited) and
> let users to modify it.
>
> 9203. RLMM has additional responsibility of handling topic delete requests.
> With current design, RLMM implementations need
> to implement deletion logic. How about making RemotePartitionRemover as a
> separate task, which can be reused..
>
> 9204. Can we list all the new error codes added by the KIP?
>
> 9205. Can we also support  `remote.log.metadata.producr.*`,
> `remote.log.metadata.consumer.*` prefixed configs to
> override any default configs ?. also include RLMM cache configs, if any.
>
> 9206. In the Upgrade section, we have below statement
> "Before enabling tiered storage, you should make sure the producer
> snapshots are built for all the segments for that topic
> in all followers. You should wait till the log retention occurs for all the
> segments so that all the segments have producer snapshots."
>
>  Can you add more details about this constraint?
>
>
> Thanks,
> Manikumar
>
> On Tue, Jan 26, 2021 at 1:12 AM Jun Rao <ju...@confluent.io> wrote:
>
> > Hi, Satish,
> >
> > Thanks for the reply. A few more comments below.
> >
> > 6000. When RSM/RLMM is not available, it seems that we need to return a
> > retriable error to the affected client requests. So, should we add a new
> > error code for requests like fetch and listOffset?
> >
> > 9111. RemotePartitionRemover:
> > 91111.1 Could we make it clear that it's part of the default RLMM
> > implementation and a separate implementation is needed if one has a
> > customized RLMM?
> > 91111.2 "RPRM gets all the remote log segments for the partition using RLMM
> > and each of these remote log segments is deleted with the next steps.RLMM
> > subscribes to the local remote log metadata partitions and it will have the
> > segment metadata of all the user topic partitions associated with that
> > remote log metadata partition." It seems that RLMM needs to subscribe to
> > the remote log metadata partitions first before those segments can be
> > deleted?
> > 9111.3 There are still references to "remote log cleaners". They need to be
> > replaced with RemotePartitionRemover.
> >
> > 9114.1 Could we add the requirement on log.message.format before enabling
> > tiered storage?
> >
> > 9116. RemoteLogMetadataFormatter: This is used with the ConsoleConsumer
> > tool, right? Then, are those new options for ConsoleConsumer and how are
> > they passed in?
> >
> > Thanks,
> >
> > Jun
> >
> >
> > On Mon, Jan 25, 2021 at 8:02 AM Satish Duggana <sa...@gmail.com>
> > wrote:
> >
> > > Hi Jun,
> > >
> > > Thanks for your comments. Please find the inline replies below.
> > > Several of these were discussed/clarified in our last discussion.
> > >
> > > 6000. Since we are returning new error codes, we need to bump up the
> > > protocol version for Fetch request. Also, it will be useful to document
> > all
> > > new error codes and whether they are retriable or not.
> > > This previous comment doesn't seem to be addressed.
> > >
> > > Updated KIP on fetch protocol and error code.
> > >
> > > 9110. flat_file_format: Could you define the serialized representation
> > for
> > > each field in the header?
> > >
> > > Added the serialized representation types in the KIP.
> > >
> > > 9111. RPM has the following 2 steps.
> > > "1. The controller publishes delete_partition_marked event to say that
> > the
> > > partition is marked for deletion. There can be multiple events published
> > > when the controller restarts or failover and this event will be
> > > deduplicated by RPM.
> > > 2. RPM receives the delete_partition_marked and processes it if it is not
> > > yet processed earlier."
> > > What triggers RPM to read __remote_log_metadata? Is RPM part of the
> > default
> > > RLMM implementation or is it meant for any RLMM implementation?
> > >
> > > RPM(or RPRM) is only for the default RLMM implementation. RPM receives
> > > the delete_partition_marked events from RLMM and acts on them. Updated
> > > KIP with more details.
> > >
> > > 9112. remote.log.manager.task.retry.backoff.ms: It would be useful to
> > make
> > > it clear in the comment that this is for the initial retry backoff.
> > >
> > > Updated the KIP.
> > >
> > > 9113. RLMM:
> > > 9113.1 updateRemoteLogSegmentMetadata(): This comment needs to be
> > updated.
> > >
> > > Updated javadoc of this method.
> > >
> > > 9113.2 Should RemoteLogSegmentMetadataUpdate include a leadeEpoch field
> > > since all other update events have leaderEpoch?
> > >
> > > +1 to have that,  updated the KIP.
> > >
> > > 9113.3 Could we rename RemotePartitionState to RemotePartitionDeleteState
> > > to make it clear this is for deletion?
> > >
> > > Sure, updated the KIP.
> > >
> > > 9113.4 Could we rename RemoteLogState to RemoteLogSegmentState to make it
> > > clear this is for segment?
> > >
> > > Sure, Updated the KIP.
> > >
> > > 9114.Upgrade:
> > > 9114.1 It seems that we require message format > 0.11 for turning on the
> > > remote store feature.
> > >
> > > 9114.2 It's not clear to me why remote.log.storage.system.enable needs to
> > > be set to true before bumping up inter.broker.protocol.version.
> > >
> > > Agree that based on our discussion, this is not required. Upgrade
> > > notes is updated.
> > >
> > > 9114.3 "If the topic-id is not received in the LeaderAndIsr request then
> > > remote log storage will not start. But it will log an error message in
> > the
> > > log. One way to address this is to do a rolling restart of that broker,
> > so
> > > that the leader will be moved to another broker and the controller will
> > > send LeaderAndIsr with the registered topic-id." Why is this needed? With
> > > KIP-516, after upgrading to the latest protocol, topicIds are auto
> > created.
> > >
> > > I thought there may be edge cases of not receiving topic-id but you
> > > clarified in the meeting that won’t be the case. I agree that it is
> > > not needed.
> > >
> > > 9115. testing: Could you comment on how we plan to do integration and
> > > system tests? Do we plan to include, for example, an in-memory
> > > implementation of RSM?
> > >
> > > For integration tests, we can have file based RSM that we have. For
> > > system tests, we can have a single node HDFS cluster in one of the
> > > containers and use HDFS RSM implementation.
> > >
> > > 9116. There is still a todo for the message formatter.
> > >
> > > Updated the KIP with the format.
> > >
> > >
> > > Satish.
> > >
> > >
> > > On Tue, 12 Jan 2021 at 07:07, Jun Rao <ju...@confluent.io> wrote:
> > > >
> > > > Hi, Satish,
> > > >
> > > > Thanks for the reply. A few more followup comments.
> > > >
> > > > 6000. Since we are returning new error codes, we need to bump up the
> > > > protocol version for Fetch request. Also, it will be useful to document
> > > all
> > > > new error codes and whether they are retriable or not.
> > > > This previous comment doesn't seem to be addressed.
> > > >
> > > > 9110. flat_file_format: Could you define the serialized representation
> > > for
> > > > each field in the header?
> > > >
> > > > 9111. RPM has the following 2 steps.
> > > > "1. The controller publishes delete_partition_marked event to say that
> > > the
> > > > partition is marked for deletion. There can be multiple events
> > published
> > > > when the controller restarts or failover and this event will be
> > > > deduplicated by RPM.
> > > > 2. RPM receives the delete_partition_marked and processes it if it is
> > not
> > > > yet processed earlier."
> > > > What triggers RPM to read __remote_log_metadata? Is RPM part of the
> > > default
> > > > RLMM implementation or is it meant for any RLMM implementation?
> > > >
> > > > 9112. remote.log.manager.task.retry.backoff.ms: It would be useful to
> > > make
> > > > it clear in the comment that this is for the initial retry backoff.
> > > >
> > > > 9113. RLMM:
> > > > 9113.1 updateRemoteLogSegmentMetadata(): This comment needs to be
> > > updated.
> > > > 9113.2 Should RemoteLogSegmentMetadataUpdate include a leadeEpoch field
> > > > since all other update events have leaderEpoch?
> > > > 9113.3 Could we rename RemotePartitionState to
> > RemotePartitionDeleteState
> > > > to make it clear this is for deletion?
> > > > 9113.4 Could we rename RemoteLogState to RemoteLogSegmentState to make
> > it
> > > > clear this is for segment?
> > > >
> > > > 9114.Upgrade:
> > > > 9114.1 It seems that we require message format > 0.11 for turning on
> > the
> > > > remote store feature.
> > > > 9114.2 It's not clear to me why remote.log.storage.system.enable needs
> > to
> > > > be set to true before bumping up inter.broker.protocol.version.
> > > > 9114.3 "If the topic-id is not received in the LeaderAndIsr request
> > then
> > > > remote log storage will not start. But it will log an error message in
> > > the
> > > > log. One way to address this is to do a rolling restart of that broker,
> > > so
> > > > that the leader will be moved to another broker and the controller will
> > > > send LeaderAndIsr with the registered topic-id." Why is this needed?
> > With
> > > > KIP-516, after upgrading to the latest protocol, topicIds are auto
> > > created.
> > > >
> > > > 9115. testing: Could you comment on how we plan to do integration and
> > > > system tests? Do we plan to include, for example, an in-memory
> > > > implementation of RSM?
> > > >
> > > > 9116. There is still a todo for the message formatter.
> > > >
> > > > Jun
> > > >
> > > > On Sat, Jan 9, 2021 at 2:04 AM Satish Duggana <
> > satish.duggana@gmail.com>
> > > > wrote:
> > > >
> > > > > Hi Jun,
> > > > > Thanks for your comments. Please find the inline replies below.
> > > > >
> > > > > 6022. For packages used for server plugins, the convention is to
> > > > > use org.apache.kafka.server. See java-based Authorizer as an example.
> > > > >
> > > > > Sure, ‘org.apache.kafka.common.log.remote.storage’ renamed to
> > > > > ‘org.apache.kafka.server.log.remote.storage’.  Updated in the KIP.
> > > > >
> > > > > 9100. Do we need DeletePartitionStateRecord in flat_file_format? The
> > > flat
> > > > > file captures the state of the remote segments. After a partition is
> > > > > deleted, it seems that we just need to remove the partitions's remote
> > > > > segments from the flat file.
> > > > >
> > > > > DeletePartitionState might not yet have been processed by RPM and not
> > > > > completed. We  will not have  that in flat  file format  once it
> > > > > reaches DELETE_PARTITION_FINISHED state.
> > > > >
> > > > > 9101. Upgrade: It will be useful to allow direct upgrade from an old
> > > > > version. It seems that's doable. One can just do the normal upgrade
> > > first
> > > > > and wait enough time (for producer snapshots to be built), and then
> > > enable
> > > > > remote storage.
> > > > >
> > > > > Upgrade notes updates in the KIP.
> > > > >
> > > > > 9102. RemotePartitionRemover(RPM) process: Is it true that RPM starts
> > > > > tracking the remote segments when RLMM.onPartitionLeadershipChanges()
> > > is
> > > > > called with the broker being the leader for __remote_log_metadata
> > > > > partition? If so, could we document it?
> > > > >
> > > > > The current plan is to have that as part of RLMM and RPM uses that to
> > > > > get the remote segments list. I will add this detail in the
> > respective
> > > > > sections.
> > > > >
> > > > > Satish.
> > > > >
> > > > > On Wed, 16 Dec 2020 at 23:55, Jun Rao <ju...@confluent.io> wrote:
> > > > > >
> > > > > > Hi, Satish,
> > > > > >
> > > > > > Thanks for the reply. A few more followup comments.
> > > > > >
> > > > > > 6022. For packages used for server plugins, the convention is to
> > > > > > use org.apache.kafka.server. See java-based Authorizer as an
> > example.
> > > > > >
> > > > > > 9100. Do we need DeletePartitionStateRecord in flat_file_format?
> > The
> > > flat
> > > > > > file captures the state of the remote segments. After a partition
> > is
> > > > > > deleted, it seems that we just need to remove the partitions's
> > remote
> > > > > > segments from the flat file.
> > > > > >
> > > > > > 9101. Upgrade: It will be useful to allow direct upgrade from an
> > old
> > > > > > version. It seems that's doable. One can just do the normal upgrade
> > > first
> > > > > > and wait enough time (for producer snapshots to be built), and then
> > > > > enable
> > > > > > remote storage.
> > > > > >
> > > > > > 9102. RemotePartitionRemover(RPM) process: Is it true that RPM
> > starts
> > > > > > tracking the remote segments when
> > > RLMM.onPartitionLeadershipChanges() is
> > > > > > called with the broker being the leader for __remote_log_metadata
> > > > > > partition? If so, could we document it?
> > > > > >
> > > > > > Jun
> > > > > >
> > > > > > On Tue, Dec 15, 2020 at 8:47 AM Kowshik Prakasam <
> > > kprakasam@confluent.io
> > > > > >
> > > > > > wrote:
> > > > > >
> > > > > > > Hi Satish,
> > > > > > >
> > > > > > > Thanks for the updates! A few more comments below.
> > > > > > >
> > > > > > > 9001. Under the "Upgrade" section, there is a line mentioning:
> > > > > "Upgrade the
> > > > > > > existing Kafka cluster to 2.7 version and allow this to run for
> > > the log
> > > > > > > retention of user topics that you want to enable tiered storage.
> > > This
> > > > > will
> > > > > > > allow all the topics to have the producer snapshots generated for
> > > each
> > > > > log
> > > > > > > segment." -- Which associated change in AK were you referring to
> > > here?
> > > > > Is
> > > > > > > it: https://github.com/apache/kafka/pull/7929 ? It seems like I
> > > don't
> > > > > see
> > > > > > > it in the 2.7 release branch yet, here is the link:
> > > > > > > https://github.com/apache/kafka/commits/2.7.
> > > > > > >
> > > > > > > 9002. Under the "Upgrade" section, the configuration mentioned is
> > > > > > > 'remote.log.storage.system.enable'. However, under "Public
> > > Interfaces"
> > > > > > > section the corresponding configuration is
> > > > > 'remote.storage.system.enable'.
> > > > > > > Could we use the same one in both, maybe
> > > > > > > 'remote.log.storage.system.enable'?
> > > > > > >
> > > > > > > 9003. Under "Per Topic Configuration", the KIP recommends setting
> > > > > > > 'remote.log.storage.enable' to true at a per-topic level. It will
> > > be
> > > > > useful
> > > > > > > to add a line that if the user wants to enable it for all topics,
> > > then
> > > > > they
> > > > > > > should be able to set the cluster-wide default to true. Also, it
> > > will
> > > > > be
> > > > > > > useful to mention that the KIP currently does not support setting
> > > it to
> > > > > > > false (after it is set to true), and add that to the future work
> > > > > section.
> > > > > > >
> > > > > > > 9004. Under "Committed offsets file format", the sample provided
> > > shows
> > > > > > > partition number and offset. Is the topic name required for
> > > identifying
> > > > > > > which topic the partitions belong to?
> > > > > > >
> > > > > > > 9005. Under "Internal flat-file store format of remote log
> > > metadata",
> > > > > it
> > > > > > > seems useful to specify both topic name and topic ID for
> > debugging
> > > > > > > purposes.
> > > > > > >
> > > > > > > 9006. Under "Internal flat-file store format of remote log
> > > metadata",
> > > > > the
> > > > > > > description of "metadata-topic-offset" currently says "offset of
> > > the
> > > > > remote
> > > > > > > log metadata topic from which this topic partition's remote log
> > > > > metadata is
> > > > > > > fetched." Just for the wording, perhaps you meant to refer to the
> > > > > offset
> > > > > > > upto which the file has been committed? i.e. "offset of the
> > remote
> > > log
> > > > > > > metadata topic upto which this topic partition's remote log
> > > metadata
> > > > > has
> > > > > > > been committed into this file."
> > > > > > >
> > > > > > > 9007. Under "Internal flat-file store format of remote log
> > > metadata",
> > > > > the
> > > > > > > schema of the payload (i.e. beyond the header) seems to contain
> > the
> > > > > events
> > > > > > > from the metadata topic. It seems useful to instead persist the
> > > > > > > representation of the materialized state of the events, so that
> > > for the
> > > > > > > same segment only the latest state is stored. Besides reducing
> > > storage
> > > > > > > footprint, this also is likely to relate directly with the
> > > in-memory
> > > > > > > representation of the RLMM cache (which probably is some kind of
> > a
> > > Map
> > > > > with
> > > > > > > key being segment ID and value being the segment state), so
> > > recovery
> > > > > from
> > > > > > > disk will be straightforward.
> > > > > > >
> > > > > > > 9008. Under "Topic deletion lifecycle", step (1), it will be
> > > useful to
> > > > > > > mention when in the deletion flow does the controller publish the
> > > > > > > delete_partition_marked event to say that the partition is marked
> > > for
> > > > > > > deletion?
> > > > > > >
> > > > > > > 9009. There are ~4 TODOs in the KIP. Could you please address
> > > these or
> > > > > > > remove them?
> > > > > > >
> > > > > > > 9010. There is a reference to a Google doc on the KIP which was
> > > used
> > > > > > > earlier for discussions. Please could you remove the reference,
> > > since
> > > > > the
> > > > > > > KIP is the source of the truth?
> > > > > > >
> > > > > > > 9011. This feedback is from an earlier comment. In the
> > > > > RemoteStorageManager
> > > > > > > interface, there is an API defined for each file type. For
> > example,
> > > > > > > fetchOffsetIndex, fetchTimestampIndex etc. To avoid the
> > > duplication,
> > > > > I'd
> > > > > > > suggest we can instead have a FileType enum and a common get API
> > > based
> > > > > on
> > > > > > > the FileType. What do you think?
> > > > > > >
> > > > > > >
> > > > > > > Cheers,
> > > > > > > Kowshik
> > > > > > >
> > > > > > >
> > > > > > > On Mon, Dec 14, 2020 at 11:07 AM Satish Duggana <
> > > > > satish.duggana@gmail.com>
> > > > > > > wrote:
> > > > > > >
> > > > > > > > Hi Jun,
> > > > > > > > Thanks for your comments. Please go through the inline replies.
> > > > > > > >
> > > > > > > >
> > > > > > > > 5102.2: It seems that both positions can just be int. Another
> > > option
> > > > > is
> > > > > > > to
> > > > > > > > have two methods. Would it be clearer?
> > > > > > > >
> > > > > > > >     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> > > > > > > > remoteLogSegmentMetadata,  int startPosition)
> > > > > > > throwsRemoteStorageException;
> > > > > > > >
> > > > > > > >     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> > > > > > > > remoteLogSegmentMetadata, int startPosition, int endPosition)
> > > throws
> > > > > > > > RemoteStorageException;
> > > > > > > >
> > > > > > > > That makes sense to me, updated the KIP.
> > > > > > > >
> > > > > > > > 6003: Could you also update the javadoc for the return value?
> > > > > > > >
> > > > > > > > Updated.
> > > > > > > >
> > > > > > > > 6020: local.log.retention.bytes: Should it default to
> > > > > log.retention.bytes
> > > > > > > > to be consistent with local.log.retention.ms?
> > > > > > > >
> > > > > > > > Yes, it can be defaulted to log.retention.bytes.
> > > > > > > >
> > > > > > > > 6021: Could you define TopicIdPartition?
> > > > > > > >
> > > > > > > > Added TopicIdPartition in the KIP.
> > > > > > > >
> > > > > > > > 6022: For all public facing classes, could you specify the
> > > package
> > > > > name?
> > > > > > > >
> > > > > > > > Updated.
> > > > > > > >
> > > > > > > >
> > > > > > > > Thanks,
> > > > > > > > Satish.
> > > > > > > >
> > > > > > > > On Tue, Dec 8, 2020 at 12:59 AM Jun Rao <ju...@confluent.io>
> > > wrote:
> > > > > > > > >
> > > > > > > > > Hi, Satish,
> > > > > > > > >
> > > > > > > > > Thanks for the reply. A few more comments below.
> > > > > > > > >
> > > > > > > > > 5102.2: It seems that both positions can just be int. Another
> > > > > option is
> > > > > > > > to
> > > > > > > > > have two methods. Would it be clearer?
> > > > > > > > >
> > > > > > > > >     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> > > > > > > > > remoteLogSegmentMetadata,
> > > > > > > > >                                     int startPosition) throws
> > > > > > > > > RemoteStorageException;
> > > > > > > > >
> > > > > > > > >     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> > > > > > > > > remoteLogSegmentMetadata,
> > > > > > > > >                                     int startPosition, int
> > > > > endPosition)
> > > > > > > > > throws RemoteStorageException;
> > > > > > > > >
> > > > > > > > > 6003: Could you also update the javadoc for the return value?
> > > > > > > > >
> > > > > > > > > 6010: What kind of tiering throughput have you seen with 5
> > > threads?
> > > > > > > > >
> > > > > > > > > 6020: local.log.retention.bytes: Should it default to
> > > > > > > log.retention.bytes
> > > > > > > > > to be consistent with local.log.retention.ms?
> > > > > > > > >
> > > > > > > > > 6021: Could you define TopicIdPartition?
> > > > > > > > >
> > > > > > > > > 6022: For all public facing classes, could you specify the
> > > package
> > > > > > > name?
> > > > > > > > >
> > > > > > > > > It seems that you already added the topicId support. Two
> > other
> > > > > > > remaining
> > > > > > > > > items are (a) the format of local tier metadata storage and
> > (b)
> > > > > > > upgrade.
> > > > > > > > >
> > > > > > > > > Jun
> > > > > > > > >
> > > > > > > > > On Mon, Dec 7, 2020 at 8:56 AM Satish Duggana <
> > > > > > > satish.duggana@gmail.com>
> > > > > > > > > wrote:
> > > > > > > > >
> > > > > > > > > > Hi Jun,
> > > > > > > > > > Thanks for your comments. Please find the inline replies
> > > below.
> > > > > > > > > >
> > > > > > > > > > >605.2 It's rare for the follower to need the remote data.
> > > So,
> > > > > the
> > > > > > > > current
> > > > > > > > > > approach is fine too. Could you document the process of
> > > > > rebuilding
> > > > > > > the
> > > > > > > > > > producer state since we can't simply trim the producerState
> > > to an
> > > > > > > > offset in
> > > > > > > > > > the middle of a segment.
> > > > > > > > > >
> > > > > > > > > > Will clarify in the KIP.
> > > > > > > > > >
> > > > > > > > > > >5102.2 Would it be clearer to make startPosiont long and
> > > > > endPosition
> > > > > > > > of
> > > > > > > > > > Optional<Long>?
> > > > > > > > > >
> > > > > > > > > > We will have arg checks with respective validation. It is
> > > not a
> > > > > good
> > > > > > > > > > practice to have arguments with optional as mentioned here.
> > > > > > > > > > https://rules.sonarsource.com/java/RSPEC-3553
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > >5102.5 LogSegmentData still has leaderEpochIndex as File
> > > > > instead of
> > > > > > > > > > ByteBuffer.
> > > > > > > > > >
> > > > > > > > > > Updated.
> > > > > > > > > >
> > > > > > > > > > >5102.7 Could you define all public methods for
> > > LogSegmentData?
> > > > > > > > > >
> > > > > > > > > > Updated.
> > > > > > > > > >
> > > > > > > > > > >5103.5 Could you change the reference to
> > > > > rlm_process_interval_ms and
> > > > > > > > > > rlm_retry_interval_ms to the new config names? Also, the
> > > retry
> > > > > > > interval
> > > > > > > > > > config seems still missing. It would be useful to support
> > > > > exponential
> > > > > > > > > > backoff with the retry interval config.
> > > > > > > > > >
> > > > > > > > > > Good point. We wanted the retry with truncated exponential
> > > > > backoff,
> > > > > > > > > > updated the KIP.
> > > > > > > > > >
> > > > > > > > > > >5111. "RLM follower fetches the earliest offset for the
> > > earliest
> > > > > > > > leader
> > > > > > > > > > epoch by calling RLMM.earliestLogOffset(TopicPartition
> > > > > > > topicPartition,
> > > > > > > > int
> > > > > > > > > > leaderEpoch) and updates that as the log start offset."
> > This
> > > > > text is
> > > > > > > > still
> > > > > > > > > > there. Also, could we remove earliestLogOffset() from RLMM?
> > > > > > > > > >
> > > > > > > > > > Updated.
> > > > > > > > > >
> > > > > > > > > > >5115. There are still references to "remote log cleaners".
> > > > > > > > > >
> > > > > > > > > > Updated.
> > > > > > > > > >
> > > > > > > > > > >6000. Since we are returning new error codes, we need to
> > > bump
> > > > > up the
> > > > > > > > > > protocol version for Fetch request. Also, it will be useful
> > > to
> > > > > > > > document all
> > > > > > > > > > new error codes and whether they are retriable or not.
> > > > > > > > > >
> > > > > > > > > > Sure, we will add that in the KIP.
> > > > > > > > > >
> > > > > > > > > > >6001. public Map<Long, Long> segmentLeaderEpochs():
> > > Currently,
> > > > > > > > leaderEpoch
> > > > > > > > > > is int32 instead of long.
> > > > > > > > > >
> > > > > > > > > > Updated.
> > > > > > > > > >
> > > > > > > > > > >6002. Is RemoteLogSegmentMetadata.markedForDeletion()
> > needed
> > > > > given
> > > > > > > > > > RemoteLogSegmentMetadata.state()?
> > > > > > > > > >
> > > > > > > > > > No, it is fixed.
> > > > > > > > > >
> > > > > > > > > > >6003. RemoteLogSegmentMetadata
> > > > > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > > topicPartition, long offset, int epochForOffset): Should
> > this
> > > > > return
> > > > > > > > > > Optional<RemoteLogSegmentMetadata>?
> > > > > > > > > >
> > > > > > > > > > That makes sense, updated.
> > > > > > > > > >
> > > > > > > > > > >6005. RemoteLogState: It seems it's better to split it
> > > between
> > > > > > > > > > DeletePartitionUpdate and RemoteLogSegmentMetadataUpdate
> > > since
> > > > > the
> > > > > > > > states
> > > > > > > > > > are never shared between the two use cases.
> > > > > > > > > >
> > > > > > > > > > Agree with that, updated.
> > > > > > > > > >
> > > > > > > > > > >6006. RLMM.onPartitionLeadershipChanges(): This may be ok.
> > > > > However,
> > > > > > > > is it
> > > > > > > > > > ture that other than the metadata topic, RLMM just needs to
> > > know
> > > > > > > > whether
> > > > > > > > > > there is a replica assigned to this broker and doesn't need
> > > to
> > > > > know
> > > > > > > > whether
> > > > > > > > > > the replica is the leader or the follower?
> > > > > > > > > >
> > > > > > > > > > That may be true. If the implementation does not need that,
> > > it
> > > > > can
> > > > > > > > > > ignore the information in the callback.
> > > > > > > > > >
> > > > > > > > > > >6007: "Handle expired remote segments (leader and
> > > follower)":
> > > > > Why is
> > > > > > > > this
> > > > > > > > > > needed in both the leader and the follower?
> > > > > > > > > >
> > > > > > > > > > Updated.
> > > > > > > > > >
> > > > > > > > > > >6008.       "name": "SegmentSizeInBytes",
> > > > > > > > > >                 "type": "int64",
> > > > > > > > > > The segment size can just be int32.
> > > > > > > > > >
> > > > > > > > > > Updated.
> > > > > > > > > >
> > > > > > > > > > >6009. For the record format in the log, it seems that we
> > > need
> > > > > to add
> > > > > > > > > > record
> > > > > > > > > > type and record version before the serialized bytes. We can
> > > > > follow
> > > > > > > the
> > > > > > > > > > convention used in
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > >
> > >
> > https://cwiki.apache.org/confluence/display/KAFKA/KIP-631%3A+The+Quorum-based+Kafka+Controller#KIP631:TheQuorumbasedKafkaController-RecordFormats
> > > > > > > > > >
> > > > > > > > > > Yes, KIP already mentions that these are serialized before
> > > the
> > > > > > > payload
> > > > > > > > > > as below. We will mention explicitly that these two are
> > > written
> > > > > > > before
> > > > > > > > > > the data is written.
> > > > > > > > > >
> > > > > > > > > > RLMM instance on broker publishes the message to the topic
> > > with
> > > > > key
> > > > > > > as
> > > > > > > > > > null and value with the below format.
> > > > > > > > > >
> > > > > > > > > > type      : unsigned var int, represents the value type.
> > This
> > > > > value
> > > > > > > is
> > > > > > > > > > 'apikey' as mentioned in the schema.
> > > > > > > > > > version : unsigned var int, the 'version' number of the
> > type
> > > as
> > > > > > > > > > mentioned in the schema.
> > > > > > > > > > data      : record payload in kafka protocol message
> > format.
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > >6010. remote.log.manager.thread.pool.size: The default
> > > value is
> > > > > 10.
> > > > > > > > This
> > > > > > > > > > might be too high when enabling the tiered feature for the
> > > first
> > > > > > > time.
> > > > > > > > > > Since there are lots of segments that need to be tiered
> > > > > initially, a
> > > > > > > > large
> > > > > > > > > > number of threads could overwhelm the broker.
> > > > > > > > > >
> > > > > > > > > > Is the default value 5 reasonable?
> > > > > > > > > >
> > > > > > > > > > 6011. "The number of milli seconds to keep the local log
> > > segment
> > > > > > > > before it
> > > > > > > > > > gets deleted. If not set, the value in
> > > `log.retention.minutes` is
> > > > > > > > used. If
> > > > > > > > > > set to -1, no time limit is applied." We should use
> > > > > log.retention.ms
> > > > > > > > > > instead of log.retention.minutes.
> > > > > > > > > > Nice typo catch. Updated the KIP.
> > > > > > > > > >
> > > > > > > > > > Thanks,
> > > > > > > > > > Satish.
> > > > > > > > > >
> > > > > > > > > > On Thu, Dec 3, 2020 at 8:03 AM Jun Rao <ju...@confluent.io>
> > > wrote:
> > > > > > > > > > >
> > > > > > > > > > > Hi, Satish,
> > > > > > > > > > >
> > > > > > > > > > > Thanks for the updated KIP. A few more comments below.
> > > > > > > > > > >
> > > > > > > > > > > 605.2 It's rare for the follower to need the remote data.
> > > So,
> > > > > the
> > > > > > > > current
> > > > > > > > > > > approach is fine too. Could you document the process of
> > > > > rebuilding
> > > > > > > > the
> > > > > > > > > > > producer state since we can't simply trim the
> > > producerState to
> > > > > an
> > > > > > > > offset
> > > > > > > > > > in
> > > > > > > > > > > the middle of a segment.
> > > > > > > > > > >
> > > > > > > > > > > 5102.2 Would it be clearer to make startPosiont long and
> > > > > > > endPosition
> > > > > > > > of
> > > > > > > > > > > Optional<Long>?
> > > > > > > > > > >
> > > > > > > > > > > 5102.5 LogSegmentData still has leaderEpochIndex as File
> > > > > instead of
> > > > > > > > > > > ByteBuffer.
> > > > > > > > > > >
> > > > > > > > > > > 5102.7 Could you define all public methods for
> > > LogSegmentData?
> > > > > > > > > > >
> > > > > > > > > > > 5103.5 Could you change the reference to
> > > > > rlm_process_interval_ms
> > > > > > > and
> > > > > > > > > > > rlm_retry_interval_ms to the new config names? Also, the
> > > retry
> > > > > > > > interval
> > > > > > > > > > > config seems still missing. It would be useful to support
> > > > > > > exponential
> > > > > > > > > > > backoff with the retry interval config.
> > > > > > > > > > >
> > > > > > > > > > > 5111. "RLM follower fetches the earliest offset for the
> > > > > earliest
> > > > > > > > leader
> > > > > > > > > > > epoch by calling RLMM.earliestLogOffset(TopicPartition
> > > > > > > > topicPartition,
> > > > > > > > > > int
> > > > > > > > > > > leaderEpoch) and updates that as the log start offset."
> > > This
> > > > > text
> > > > > > > is
> > > > > > > > > > still
> > > > > > > > > > > there. Also, could we remove earliestLogOffset() from
> > RLMM?
> > > > > > > > > > >
> > > > > > > > > > > 5115. There are still references to "remote log
> > cleaners".
> > > > > > > > > > >
> > > > > > > > > > > 6000. Since we are returning new error codes, we need to
> > > bump
> > > > > up
> > > > > > > the
> > > > > > > > > > > protocol version for Fetch request. Also, it will be
> > > useful to
> > > > > > > > document
> > > > > > > > > > all
> > > > > > > > > > > new error codes and whether they are retriable or not.
> > > > > > > > > > >
> > > > > > > > > > > 6001. public Map<Long, Long> segmentLeaderEpochs():
> > > Currently,
> > > > > > > > > > leaderEpoch
> > > > > > > > > > > is int32 instead of long.
> > > > > > > > > > >
> > > > > > > > > > > 6002. Is RemoteLogSegmentMetadata.markedForDeletion()
> > > needed
> > > > > given
> > > > > > > > > > > RemoteLogSegmentMetadata.state()?
> > > > > > > > > > >
> > > > > > > > > > > 6003. RemoteLogSegmentMetadata
> > > > > > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > > > topicPartition, long offset, int epochForOffset): Should
> > > this
> > > > > > > return
> > > > > > > > > > > Optional<RemoteLogSegmentMetadata>?
> > > > > > > > > > >
> > > > > > > > > > > 6004. DeletePartitionUpdate.epoch(): It would be useful
> > to
> > > > > pick a
> > > > > > > > more
> > > > > > > > > > > indicative name so that people understand what epoch this
> > > is.
> > > > > > > > > > >
> > > > > > > > > > > 6005. RemoteLogState: It seems it's better to split it
> > > between
> > > > > > > > > > > DeletePartitionUpdate and RemoteLogSegmentMetadataUpdate
> > > since
> > > > > the
> > > > > > > > states
> > > > > > > > > > > are never shared between the two use cases.
> > > > > > > > > > >
> > > > > > > > > > > 6006. RLMM.onPartitionLeadershipChanges(): This may be
> > ok.
> > > > > However,
> > > > > > > > is it
> > > > > > > > > > > ture that other than the metadata topic, RLMM just needs
> > to
> > > > > know
> > > > > > > > whether
> > > > > > > > > > > there is a replica assigned to this broker and doesn't
> > > need to
> > > > > know
> > > > > > > > > > whether
> > > > > > > > > > > the replica is the leader or the follower?
> > > > > > > > > > >
> > > > > > > > > > > 6007: "Handle expired remote segments (leader and
> > > follower)":
> > > > > Why
> > > > > > > is
> > > > > > > > this
> > > > > > > > > > > needed in both the leader and the follower?
> > > > > > > > > > >
> > > > > > > > > > > 6008.       "name": "SegmentSizeInBytes",
> > > > > > > > > > >                 "type": "int64",
> > > > > > > > > > > The segment size can just be int32.
> > > > > > > > > > >
> > > > > > > > > > > 6009. For the record format in the log, it seems that we
> > > need
> > > > > to
> > > > > > > add
> > > > > > > > > > record
> > > > > > > > > > > type and record version before the serialized bytes. We
> > can
> > > > > follow
> > > > > > > > the
> > > > > > > > > > > convention used in
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > >
> > >
> > https://cwiki.apache.org/confluence/display/KAFKA/KIP-631%3A+The+Quorum-based+Kafka+Controller#KIP631:TheQuorumbasedKafkaController-RecordFormats
> > > > > > > > > > > .
> > > > > > > > > > >
> > > > > > > > > > > 6010. remote.log.manager.thread.pool.size: The default
> > > value
> > > > > is 10.
> > > > > > > > This
> > > > > > > > > > > might be too high when enabling the tiered feature for
> > the
> > > > > first
> > > > > > > > time.
> > > > > > > > > > > Since there are lots of segments that need to be tiered
> > > > > initially,
> > > > > > > a
> > > > > > > > > > large
> > > > > > > > > > > number of threads could overwhelm the broker.
> > > > > > > > > > >
> > > > > > > > > > > 6011. "The number of milli seconds to keep the local log
> > > > > segment
> > > > > > > > before
> > > > > > > > > > it
> > > > > > > > > > > gets deleted. If not set, the value in
> > > `log.retention.minutes`
> > > > > is
> > > > > > > > used.
> > > > > > > > > > If
> > > > > > > > > > > set to -1, no time limit is applied." We should use
> > > > > > > log.retention.ms
> > > > > > > > > > > instead of log.retention.minutes.
> > > > > > > > > > >
> > > > > > > > > > > Jun
> > > > > > > > > > >
> > > > > > > > > > > On Tue, Dec 1, 2020 at 2:42 AM Satish Duggana <
> > > > > > > > satish.duggana@gmail.com>
> > > > > > > > > > > wrote:
> > > > > > > > > > >
> > > > > > > > > > > > Hi,
> > > > > > > > > > > > We updated the KIP with the points mentioned in the
> > > earlier
> > > > > mail
> > > > > > > > > > > > except for KIP-516 related changes. You can go through
> > > them
> > > > > and
> > > > > > > > let us
> > > > > > > > > > > > know if you have any comments. We will update the KIP
> > > with
> > > > > the
> > > > > > > > > > > > remaining todo items and KIP-516 related changes by end
> > > of
> > > > > this
> > > > > > > > > > > > week(5th Dec).
> > > > > > > > > > > >
> > > > > > > > > > > > Thanks,
> > > > > > > > > > > > Satish.
> > > > > > > > > > > >
> > > > > > > > > > > > On Tue, Nov 10, 2020 at 8:26 PM Satish Duggana <
> > > > > > > > > > satish.duggana@gmail.com>
> > > > > > > > > > > > wrote:
> > > > > > > > > > > > >
> > > > > > > > > > > > > Hi Jun,
> > > > > > > > > > > > > Thanks for your comments. Please find the inline
> > > replies
> > > > > below.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 605.2 "Build the local leader epoch cache by cutting
> > > the
> > > > > leader
> > > > > > > > epoch
> > > > > > > > > > > > > sequence received from remote storage to [LSO,
> > ELO]." I
> > > > > > > > mentioned an
> > > > > > > > > > > > issue
> > > > > > > > > > > > > earlier. Suppose the leader's local start offset is
> > > 100.
> > > > > The
> > > > > > > > follower
> > > > > > > > > > > > finds
> > > > > > > > > > > > > a remote segment covering offset range [80, 120). The
> > > > > > > > producerState
> > > > > > > > > > with
> > > > > > > > > > > > > this remote segment is up to offset 120. To trim the
> > > > > > > > producerState to
> > > > > > > > > > > > > offset 100 requires more work since one needs to
> > > download
> > > > > the
> > > > > > > > > > previous
> > > > > > > > > > > > > producerState up to offset 80 and then replay the
> > > messages
> > > > > from
> > > > > > > > 80 to
> > > > > > > > > > > > 100.
> > > > > > > > > > > > > It seems that it's simpler in this case for the
> > > follower
> > > > > just
> > > > > > > to
> > > > > > > > > > take the
> > > > > > > > > > > > > remote segment as it is and start fetching from
> > offset
> > > 120.
> > > > > > > > > > > > >
> > > > > > > > > > > > > We chose that approach to avoid any edge cases here.
> > It
> > > > > may be
> > > > > > > > > > > > > possible that the remote log segment that is received
> > > may
> > > > > not
> > > > > > > > have
> > > > > > > > > > the
> > > > > > > > > > > > > same leader epoch sequence from 100-120 as it
> > contains
> > > on
> > > > > the
> > > > > > > > > > > > > leader(this can happen due to unclean leader). It is
> > > safe
> > > > > to
> > > > > > > > start
> > > > > > > > > > > > > from what the leader returns here.Another way is to
> > > find
> > > > > the
> > > > > > > > remote
> > > > > > > > > > > > > log segment
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5016. Just to echo what Kowshik was saying. It seems
> > > that
> > > > > > > > > > > > > RLMM.onPartitionLeadershipChanges() is only called on
> > > the
> > > > > > > > replicas
> > > > > > > > > > for a
> > > > > > > > > > > > > partition, not on the replicas for the
> > > > > > > > __remote_log_segment_metadata
> > > > > > > > > > > > > partition. It's not clear how the leader of
> > > > > > > > > > __remote_log_segment_metadata
> > > > > > > > > > > > > obtains the metadata for remote segments for
> > deletion.
> > > > > > > > > > > > >
> > > > > > > > > > > > > RLMM will always receive the callback for the remote
> > > log
> > > > > > > metadata
> > > > > > > > > > > > > topic partitions hosted on the local broker and these
> > > will
> > > > > be
> > > > > > > > > > > > > subscribed. I will make this clear in the KIP.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5100. KIP-516 has been accepted and is being
> > > implemented
> > > > > now.
> > > > > > > > Could
> > > > > > > > > > you
> > > > > > > > > > > > > update the KIP based on topicID?
> > > > > > > > > > > > >
> > > > > > > > > > > > > We mentioned KIP-516 and how it helps. We will update
> > > this
> > > > > KIP
> > > > > > > > with
> > > > > > > > > > > > > all the changes it brings with KIP-516.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5101. RLMM: It would be useful to clarify how the
> > > > > following two
> > > > > > > > APIs
> > > > > > > > > > are
> > > > > > > > > > > > > used. According to the wiki, the former is used for
> > > topic
> > > > > > > > deletion
> > > > > > > > > > and
> > > > > > > > > > > > the
> > > > > > > > > > > > > latter is used for retention. It seems that retention
> > > > > should
> > > > > > > use
> > > > > > > > the
> > > > > > > > > > > > former
> > > > > > > > > > > > > since remote segments without a matching epoch in the
> > > > > leader
> > > > > > > > > > (potentially
> > > > > > > > > > > > > due to unclean leader election) also need to be
> > garbage
> > > > > > > > collected.
> > > > > > > > > > The
> > > > > > > > > > > > > latter seems to be used for the new leader to
> > > determine the
> > > > > > > last
> > > > > > > > > > tiered
> > > > > > > > > > > > > segment.
> > > > > > > > > > > > >     default Iterator<RemoteLogSegmentMetadata>
> > > > > > > > > > > > > listRemoteLogSegments(TopicPartition topicPartition)
> > > > > > > > > > > > >     Iterator<RemoteLogSegmentMetadata>
> > > > > > > > > > > > listRemoteLogSegments(TopicPartition
> > > > > > > > > > > > > topicPartition, long leaderEpoch);
> > > > > > > > > > > > >
> > > > > > > > > > > > > Right,.that is what we are currently doing. We will
> > > update
> > > > > the
> > > > > > > > > > > > > javadocs and wiki with that. Earlier, we did not want
> > > to
> > > > > remove
> > > > > > > > the
> > > > > > > > > > > > > segments which are not matched with leader epochs
> > from
> > > the
> > > > > > > ladder
> > > > > > > > > > > > > partition as they may be used later by a replica
> > which
> > > can
> > > > > > > > become a
> > > > > > > > > > > > > leader (unclean leader election) and refer those
> > > segments.
> > > > > But
> > > > > > > > that
> > > > > > > > > > > > > may leak these segments in remote storage until the
> > > topic
> > > > > > > > lifetime.
> > > > > > > > > > We
> > > > > > > > > > > > > decided to cleanup the segments with the oldest
> > incase
> > > of
> > > > > size
> > > > > > > > based
> > > > > > > > > > > > > retention also.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5102. RSM:
> > > > > > > > > > > > > 5102.1 For methods like fetchLogSegmentData(), it
> > seems
> > > > > that
> > > > > > > > they can
> > > > > > > > > > > > > use RemoteLogSegmentId instead of
> > > RemoteLogSegmentMetadata.
> > > > > > > > > > > > >
> > > > > > > > > > > > > It will be useful to have metadata for RSM to fetch
> > log
> > > > > > > segment.
> > > > > > > > It
> > > > > > > > > > > > > may create location/path using id with other metadata
> > > too.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5102.2 In fetchLogSegmentData(), should we use long
> > > > > instead of
> > > > > > > > Long?
> > > > > > > > > > > > >
> > > > > > > > > > > > > Wanted to keep endPosition as optional to read till
> > the
> > > > > end of
> > > > > > > > the
> > > > > > > > > > > > > segment and avoid sentinels.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5102.3 Why only some of the methods have default
> > > > > implementation
> > > > > > > > and
> > > > > > > > > > > > others
> > > > > > > > > > > > > Don't?
> > > > > > > > > > > > >
> > > > > > > > > > > > > Actually,  RSM will not have any default
> > > implementations.
> > > > > > > Those 3
> > > > > > > > > > > > > methods were made default earlier for tests etc.
> > > Updated
> > > > > the
> > > > > > > > wiki.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5102.4. Could we define
> > RemoteLogSegmentMetadataUpdate
> > > > > > > > > > > > > and DeletePartitionUpdate?
> > > > > > > > > > > > >
> > > > > > > > > > > > > Sure, they will be added.
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5102.5 LogSegmentData: It seems that it's easier to
> > > pass
> > > > > > > > > > > > > in leaderEpochIndex as a ByteBuffer or byte array
> > than
> > > a
> > > > > file
> > > > > > > > since
> > > > > > > > > > it
> > > > > > > > > > > > will
> > > > > > > > > > > > > be generated in memory.
> > > > > > > > > > > > >
> > > > > > > > > > > > > Right, this is in plan.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5102.6 RemoteLogSegmentMetadata: It seems that it
> > needs
> > > > > both
> > > > > > > > > > baseOffset
> > > > > > > > > > > > and
> > > > > > > > > > > > > startOffset. For example, deleteRecords() could move
> > > the
> > > > > > > > startOffset
> > > > > > > > > > to
> > > > > > > > > > > > the
> > > > > > > > > > > > > middle of a segment. If we copy the full segment to
> > > remote
> > > > > > > > storage,
> > > > > > > > > > the
> > > > > > > > > > > > > baseOffset and the startOffset will be different.
> > > > > > > > > > > > >
> > > > > > > > > > > > > Good point. startOffset is baseOffset by default, if
> > > not
> > > > > set
> > > > > > > > > > explicitly.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5102.7 Could we define all the public methods for
> > > > > > > > > > > > RemoteLogSegmentMetadata
> > > > > > > > > > > > > and LogSegmentData?
> > > > > > > > > > > > >
> > > > > > > > > > > > > Sure, updated the wiki.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5102.8 Could we document whether endOffset in
> > > > > > > > > > RemoteLogSegmentMetadata is
> > > > > > > > > > > > > inclusive/exclusive?
> > > > > > > > > > > > >
> > > > > > > > > > > > > It is inclusive, will update.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5103. configs:
> > > > > > > > > > > > > 5103.1 Could we define the default value of
> > > non-required
> > > > > > > configs
> > > > > > > > > > (e.g the
> > > > > > > > > > > > > size of new thread pools)?
> > > > > > > > > > > > >
> > > > > > > > > > > > > Sure, that makes sense.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5103.2 It seems that local.log.retention.ms should
> > > > > default to
> > > > > > > > > > > > retention.ms,
> > > > > > > > > > > > > instead of remote.log.retention.minutes. Similarly,
> > it
> > > > > seems
> > > > > > > > > > > > > that local.log.retention.bytes should default to
> > > > > segment.bytes.
> > > > > > > > > > > > >
> > > > > > > > > > > > > Right, we do not have  remote.log.retention as we
> > > discussed
> > > > > > > > earlier.
> > > > > > > > > > > > > Thanks for catching the typo.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5103.3 remote.log.manager.thread.pool.size: The
> > > description
> > > > > > > says
> > > > > > > > > > "used in
> > > > > > > > > > > > > scheduling tasks to copy segments, fetch remote log
> > > > > indexes and
> > > > > > > > > > clean up
> > > > > > > > > > > > > remote log segments". However, there is a separate
> > > > > > > > > > > > > config remote.log.reader.threads for fetching remote
> > > data.
> > > > > It's
> > > > > > > > > > weird to
> > > > > > > > > > > > > fetch remote index and log in different thread pools
> > > since
> > > > > both
> > > > > > > > are
> > > > > > > > > > used
> > > > > > > > > > > > > for serving fetch requests.
> > > > > > > > > > > > >
> > > > > > > > > > > > > Right, remote.log.manager.thread.pool is mainly used
> > > for
> > > > > > > > copy/cleanup
> > > > > > > > > > > > > activities. Fetch path always goes through
> > > > > > > > remote.log.reader.threads.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5103.4 remote.log.manager.task.interval.ms: Is that
> > > the
> > > > > amount
> > > > > > > > of
> > > > > > > > > > time
> > > > > > > > > > > > to
> > > > > > > > > > > > > back off when there is no work to do? If so, perhaps
> > it
> > > > > can be
> > > > > > > > > > renamed as
> > > > > > > > > > > > > backoff.ms.
> > > > > > > > > > > > >
> > > > > > > > > > > > > This is the delay interval for each iteration. It may
> > > be
> > > > > > > renamed
> > > > > > > > to
> > > > > > > > > > > > > remote.log.manager.task.delay.ms
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5103.5 Are rlm_process_interval_ms and
> > > > > rlm_retry_interval_ms
> > > > > > > > > > configs? If
> > > > > > > > > > > > > so, they need to be listed in this section.
> > > > > > > > > > > > >
> > > > > > > > > > > > > remote.log.manager.task.interval.ms is the process
> > > > > internal,
> > > > > > > > retry
> > > > > > > > > > > > > interval is missing in the configs, which will be
> > > updated
> > > > > in
> > > > > > > the
> > > > > > > > KIP.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5104. "RLM maintains a bounded cache(possibly LRU) of
> > > the
> > > > > index
> > > > > > > > > > files of
> > > > > > > > > > > > > remote log segments to avoid multiple index fetches
> > > from
> > > > > the
> > > > > > > > remote
> > > > > > > > > > > > > storage." Is the RLM in memory or on disk? If on
> > disk,
> > > > > where is
> > > > > > > > it
> > > > > > > > > > > > stored?
> > > > > > > > > > > > > Do we need a configuration to bound the size?
> > > > > > > > > > > > >
> > > > > > > > > > > > > It is stored on disk. They are stored in a directory
> > > > > > > > > > > > > `remote-log-index-cache` under log dir. We plan to
> > > have a
> > > > > > > config
> > > > > > > > for
> > > > > > > > > > > > > that instead of default. We will have a configuration
> > > for
> > > > > that.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5105. The KIP uses local-log-start-offset and
> > Earliest
> > > > > Local
> > > > > > > > Offset
> > > > > > > > > > in
> > > > > > > > > > > > > different places. It would be useful to standardize
> > the
> > > > > > > > terminology.
> > > > > > > > > > > > >
> > > > > > > > > > > > > Sure.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5106. The section on "In BuildingRemoteLogAux state".
> > > It
> > > > > listed
> > > > > > > > two
> > > > > > > > > > > > options
> > > > > > > > > > > > > without saying which option is chosen.
> > > > > > > > > > > > > We already mentioned in the KIP that we chose
> > option-2.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5107. Follower to leader transition: It has step 2,
> > > but not
> > > > > > > step
> > > > > > > > 1.
> > > > > > > > > > > > > Step-1 is there but it is not explicitly highlighted.
> > > It is
> > > > > > > > previous
> > > > > > > > > > > > > table to step-2.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5108. If a consumer fetches from the remote data and
> > > the
> > > > > remote
> > > > > > > > > > storage
> > > > > > > > > > > > is
> > > > > > > > > > > > > not available, what error code is used in the fetch
> > > > > response?
> > > > > > > > > > > > >
> > > > > > > > > > > > > Good point. We have not yet defined the error for
> > this
> > > > > case. We
> > > > > > > > need
> > > > > > > > > > > > > to define an error message and send the same in fetch
> > > > > response.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5109. "ListOffsets: For timestamps >= 0, it returns
> > the
> > > > > first
> > > > > > > > message
> > > > > > > > > > > > > offset whose timestamp is >= to the given timestamp
> > in
> > > the
> > > > > > > > request.
> > > > > > > > > > That
> > > > > > > > > > > > > means it checks in remote log time indexes first,
> > after
> > > > > which
> > > > > > > > local
> > > > > > > > > > log
> > > > > > > > > > > > > time indexes are checked." Could you document which
> > > method
> > > > > in
> > > > > > > > RLMM is
> > > > > > > > > > > > used
> > > > > > > > > > > > > for this?
> > > > > > > > > > > > >
> > > > > > > > > > > > > Okay.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5110. Stopreplica: "it sets all the remote log
> > segment
> > > > > metadata
> > > > > > > > of
> > > > > > > > > > that
> > > > > > > > > > > > > partition with a delete marker and publishes them to
> > > RLMM."
> > > > > > > This
> > > > > > > > > > seems
> > > > > > > > > > > > > outdated given the new topic deletion logic.
> > > > > > > > > > > > >
> > > > > > > > > > > > > Will update with KIP-516 related points.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5111. "RLM follower fetches the earliest offset for
> > the
> > > > > > > earliest
> > > > > > > > > > leader
> > > > > > > > > > > > > epoch by calling
> > RLMM.earliestLogOffset(TopicPartition
> > > > > > > > > > topicPartition,
> > > > > > > > > > > > int
> > > > > > > > > > > > > leaderEpoch) and updates that as the log start
> > > offset." Do
> > > > > we
> > > > > > > > need
> > > > > > > > > > that
> > > > > > > > > > > > > since replication propagates logStartOffset already?
> > > > > > > > > > > > >
> > > > > > > > > > > > > Good point. Right, existing replication protocol
> > takes
> > > > > care of
> > > > > > > > > > > > > updating the followers’s log start offset received
> > > from the
> > > > > > > > leader.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5112. Is the default maxWaitMs of 500ms enough for
> > > fetching
> > > > > > > from
> > > > > > > > > > remote
> > > > > > > > > > > > > storage?
> > > > > > > > > > > > >
> > > > > > > > > > > > > Remote reads may fail within the current default wait
> > > > > time, but
> > > > > > > > > > > > > subsequent fetches would be able to serve as that
> > data
> > > is
> > > > > > > stored
> > > > > > > > in
> > > > > > > > > > > > > the local cache. This cache is currently implemented
> > in
> > > > > RSMs.
> > > > > > > > But we
> > > > > > > > > > > > > plan to pull this into the remote log messaging layer
> > > in
> > > > > > > future.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5113. "Committed offsets can be stored in a local
> > file
> > > to
> > > > > avoid
> > > > > > > > > > reading
> > > > > > > > > > > > the
> > > > > > > > > > > > > messages again when a broker is restarted." Could you
> > > > > describe
> > > > > > > > the
> > > > > > > > > > format
> > > > > > > > > > > > > and the location of the file? Also, could the same
> > > message
> > > > > be
> > > > > > > > > > processed
> > > > > > > > > > > > by
> > > > > > > > > > > > > RLMM again after broker restart? If so, how do we
> > > handle
> > > > > that?
> > > > > > > > > > > > >
> > > > > > > > > > > > > Sure, we will update in the KIP.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5114. Message format
> > > > > > > > > > > > > 5114.1 There are two records named
> > > > > > > RemoteLogSegmentMetadataRecord
> > > > > > > > > > with
> > > > > > > > > > > > > apiKey 0 and 1.
> > > > > > > > > > > > >
> > > > > > > > > > > > > Nice catch, that was a typo. Fixed in the wiki.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5114.2 RemoteLogSegmentMetadataRecord: Could we
> > > document
> > > > > > > whether
> > > > > > > > > > > > endOffset
> > > > > > > > > > > > > is inclusive/exclusive?
> > > > > > > > > > > > > It is inclusive, will update.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5114.3 RemoteLogSegmentMetadataRecord: Could you
> > > explain
> > > > > > > > LeaderEpoch
> > > > > > > > > > a
> > > > > > > > > > > > bit
> > > > > > > > > > > > > more? Is that the epoch of the leader when it copies
> > > the
> > > > > > > segment
> > > > > > > > to
> > > > > > > > > > > > remote
> > > > > > > > > > > > > storage? Also, how will this field be used?
> > > > > > > > > > > > >
> > > > > > > > > > > > > Right, this is the leader epoch of the broker which
> > > copied
> > > > > this
> > > > > > > > > > > > > segment. This is helpful in reason about which broker
> > > > > copied
> > > > > > > the
> > > > > > > > > > > > > segment to remote storage.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5114.4 EventTimestamp: Could you explain this a bit
> > > more?
> > > > > Each
> > > > > > > > > > record in
> > > > > > > > > > > > > Kafka already has a timestamp field. Could we just
> > use
> > > > > that?
> > > > > > > > > > > > >
> > > > > > > > > > > > > This is the  timestamp at which  the respective event
> > > > > occurred.
> > > > > > > > Added
> > > > > > > > > > > > > this  to RemoteLogSegmentMetadata as RLMM can be  any
> > > other
> > > > > > > > > > > > > implementation. We thought about that but it looked
> > > > > cleaner to
> > > > > > > > use at
> > > > > > > > > > > > > the message structure level instead of getting that
> > > from
> > > > > the
> > > > > > > > consumer
> > > > > > > > > > > > > record and using that to build the respective event.
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5114.5 SegmentSizeInBytes: Could this just be int32?
> > > > > > > > > > > > >
> > > > > > > > > > > > > Right, it looks like config allows only int value >=
> > > 14.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5115. RemoteLogCleaner(RLC): This could be confused
> > > with
> > > > > the
> > > > > > > log
> > > > > > > > > > cleaner
> > > > > > > > > > > > > for compaction. Perhaps it can be renamed to sth like
> > > > > > > > > > > > > RemotePartitionRemover.
> > > > > > > > > > > > >
> > > > > > > > > > > > > I am fine with RemotePartitionRemover or
> > > > > > > > RemoteLogDeletionManager(we
> > > > > > > > > > > > > have other manager classes like RLM, RLMM).
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5116. "RLC receives the delete_partition_marked and
> > > > > processes
> > > > > > > it
> > > > > > > > if
> > > > > > > > > > it is
> > > > > > > > > > > > > not yet processed earlier." How does it know whether
> > > > > > > > > > > > > delete_partition_marked has been processed earlier?
> > > > > > > > > > > > >
> > > > > > > > > > > > > This is to handle duplicate delete_partition_marked
> > > > > events. RLC
> > > > > > > > > > > > > internally maintains a state for the delete_partition
> > > > > events
> > > > > > > and
> > > > > > > > if
> > > > > > > > > > it
> > > > > > > > > > > > > already has an existing event then it ignores if it
> > is
> > > > > already
> > > > > > > > being
> > > > > > > > > > > > > processed.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5117. Should we add a new MessageFormatter to read
> > the
> > > tier
> > > > > > > > metadata
> > > > > > > > > > > > topic?
> > > > > > > > > > > > >
> > > > > > > > > > > > > Right, this is in plan but did not mention it in the
> > > KIP.
> > > > > This
> > > > > > > > will
> > > > > > > > > > be
> > > > > > > > > > > > > useful for debugging purposes too.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5118. "Maximum remote log reader thread pool task
> > queue
> > > > > size.
> > > > > > > If
> > > > > > > > the
> > > > > > > > > > task
> > > > > > > > > > > > > queue is full, broker will stop reading remote log
> > > > > segments."
> > > > > > > > What
> > > > > > > > > > do we
> > > > > > > > > > > > > return to the fetch request in this case?
> > > > > > > > > > > > >
> > > > > > > > > > > > > We return an error response for that partition.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5119. It would be useful to list all things not
> > > supported
> > > > > in
> > > > > > > the
> > > > > > > > > > first
> > > > > > > > > > > > > version in a Future work or Limitations section. For
> > > > > example,
> > > > > > > > > > compacted
> > > > > > > > > > > > > topic, JBOD, changing remote.log.storage.enable from
> > > true
> > > > > to
> > > > > > > > false,
> > > > > > > > > > etc.
> > > > > > > > > > > > >
> > > > > > > > > > > > > We already have a non-goals section which is filled
> > > with
> > > > > some
> > > > > > > of
> > > > > > > > > > these
> > > > > > > > > > > > > details. Do we need another limitations section?
> > > > > > > > > > > > >
> > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > Satish.
> > > > > > > > > > > > >
> > > > > > > > > > > > > On Wed, Nov 4, 2020 at 11:27 PM Jun Rao <
> > > jun@confluent.io>
> > > > > > > > wrote:
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Hi, Satish,
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Thanks for the updated KIP. A few more comments
> > > below.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 605.2 "Build the local leader epoch cache by
> > cutting
> > > the
> > > > > > > leader
> > > > > > > > > > epoch
> > > > > > > > > > > > > > sequence received from remote storage to [LSO,
> > > ELO]." I
> > > > > > > > mentioned
> > > > > > > > > > an
> > > > > > > > > > > > issue
> > > > > > > > > > > > > > earlier. Suppose the leader's local start offset is
> > > 100.
> > > > > The
> > > > > > > > > > follower
> > > > > > > > > > > > finds
> > > > > > > > > > > > > > a remote segment covering offset range [80, 120).
> > The
> > > > > > > > producerState
> > > > > > > > > > > > with
> > > > > > > > > > > > > > this remote segment is up to offset 120. To trim
> > the
> > > > > > > > producerState
> > > > > > > > > > to
> > > > > > > > > > > > > > offset 100 requires more work since one needs to
> > > > > download the
> > > > > > > > > > previous
> > > > > > > > > > > > > > producerState up to offset 80 and then replay the
> > > > > messages
> > > > > > > > from 80
> > > > > > > > > > to
> > > > > > > > > > > > 100.
> > > > > > > > > > > > > > It seems that it's simpler in this case for the
> > > follower
> > > > > just
> > > > > > > > to
> > > > > > > > > > take
> > > > > > > > > > > > the
> > > > > > > > > > > > > > remote segment as it is and start fetching from
> > > offset
> > > > > 120.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5016. Just to echo what Kowshik was saying. It
> > seems
> > > that
> > > > > > > > > > > > > > RLMM.onPartitionLeadershipChanges() is only called
> > > on the
> > > > > > > > replicas
> > > > > > > > > > for
> > > > > > > > > > > > a
> > > > > > > > > > > > > > partition, not on the replicas for the
> > > > > > > > > > __remote_log_segment_metadata
> > > > > > > > > > > > > > partition. It's not clear how the leader of
> > > > > > > > > > > > __remote_log_segment_metadata
> > > > > > > > > > > > > > obtains the metadata for remote segments for
> > > deletion.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5100. KIP-516 has been accepted and is being
> > > implemented
> > > > > now.
> > > > > > > > > > Could you
> > > > > > > > > > > > > > update the KIP based on topicID?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5101. RLMM: It would be useful to clarify how the
> > > > > following
> > > > > > > two
> > > > > > > > > > APIs
> > > > > > > > > > > > are
> > > > > > > > > > > > > > used. According to the wiki, the former is used for
> > > topic
> > > > > > > > deletion
> > > > > > > > > > and
> > > > > > > > > > > > the
> > > > > > > > > > > > > > latter is used for retention. It seems that
> > retention
> > > > > should
> > > > > > > > use
> > > > > > > > > > the
> > > > > > > > > > > > former
> > > > > > > > > > > > > > since remote segments without a matching epoch in
> > the
> > > > > leader
> > > > > > > > > > > > (potentially
> > > > > > > > > > > > > > due to unclean leader election) also need to be
> > > garbage
> > > > > > > > collected.
> > > > > > > > > > The
> > > > > > > > > > > > > > latter seems to be used for the new leader to
> > > determine
> > > > > the
> > > > > > > > last
> > > > > > > > > > tiered
> > > > > > > > > > > > > > segment.
> > > > > > > > > > > > > >     default Iterator<RemoteLogSegmentMetadata>
> > > > > > > > > > > > > > listRemoteLogSegments(TopicPartition
> > topicPartition)
> > > > > > > > > > > > > >     Iterator<RemoteLogSegmentMetadata>
> > > > > > > > > > > > listRemoteLogSegments(TopicPartition
> > > > > > > > > > > > > > topicPartition, long leaderEpoch);
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5102. RSM:
> > > > > > > > > > > > > > 5102.1 For methods like fetchLogSegmentData(), it
> > > seems
> > > > > that
> > > > > > > > they
> > > > > > > > > > can
> > > > > > > > > > > > > > use RemoteLogSegmentId instead of
> > > > > RemoteLogSegmentMetadata.
> > > > > > > > > > > > > > 5102.2 In fetchLogSegmentData(), should we use long
> > > > > instead
> > > > > > > of
> > > > > > > > > > Long?
> > > > > > > > > > > > > > 5102.3 Why only some of the methods have default
> > > > > > > > implementation and
> > > > > > > > > > > > others
> > > > > > > > > > > > > > don't?
> > > > > > > > > > > > > > 5102.4. Could we define
> > > RemoteLogSegmentMetadataUpdate
> > > > > > > > > > > > > > and DeletePartitionUpdate?
> > > > > > > > > > > > > > 5102.5 LogSegmentData: It seems that it's easier to
> > > pass
> > > > > > > > > > > > > > in leaderEpochIndex as a ByteBuffer or byte array
> > > than a
> > > > > file
> > > > > > > > > > since it
> > > > > > > > > > > > will
> > > > > > > > > > > > > > be generated in memory.
> > > > > > > > > > > > > > 5102.6 RemoteLogSegmentMetadata: It seems that it
> > > needs
> > > > > both
> > > > > > > > > > > > baseOffset and
> > > > > > > > > > > > > > startOffset. For example, deleteRecords() could
> > move
> > > the
> > > > > > > > > > startOffset
> > > > > > > > > > > > to the
> > > > > > > > > > > > > > middle of a segment. If we copy the full segment to
> > > > > remote
> > > > > > > > > > storage, the
> > > > > > > > > > > > > > baseOffset and the startOffset will be different.
> > > > > > > > > > > > > > 5102.7 Could we define all the public methods for
> > > > > > > > > > > > RemoteLogSegmentMetadata
> > > > > > > > > > > > > > and LogSegmentData?
> > > > > > > > > > > > > > 5102.8 Could we document whether endOffset in
> > > > > > > > > > RemoteLogSegmentMetadata
> > > > > > > > > > > > is
> > > > > > > > > > > > > > inclusive/exclusive?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5103. configs:
> > > > > > > > > > > > > > 5103.1 Could we define the default value of
> > > non-required
> > > > > > > > configs
> > > > > > > > > > (e.g
> > > > > > > > > > > > the
> > > > > > > > > > > > > > size of new thread pools)?
> > > > > > > > > > > > > > 5103.2 It seems that local.log.retention.ms should
> > > > > default
> > > > > > > to
> > > > > > > > > > > > retention.ms,
> > > > > > > > > > > > > > instead of remote.log.retention.minutes. Similarly,
> > > it
> > > > > seems
> > > > > > > > > > > > > > that local.log.retention.bytes should default to
> > > > > > > segment.bytes.
> > > > > > > > > > > > > > 5103.3 remote.log.manager.thread.pool.size: The
> > > > > description
> > > > > > > > says
> > > > > > > > > > "used
> > > > > > > > > > > > in
> > > > > > > > > > > > > > scheduling tasks to copy segments, fetch remote log
> > > > > indexes
> > > > > > > and
> > > > > > > > > > clean
> > > > > > > > > > > > up
> > > > > > > > > > > > > > remote log segments". However, there is a separate
> > > > > > > > > > > > > > config remote.log.reader.threads for fetching
> > remote
> > > > > data.
> > > > > > > It's
> > > > > > > > > > weird
> > > > > > > > > > > > to
> > > > > > > > > > > > > > fetch remote index and log in different thread
> > pools
> > > > > since
> > > > > > > > both are
> > > > > > > > > > > > used
> > > > > > > > > > > > > > for serving fetch requests.
> > > > > > > > > > > > > > 5103.4 remote.log.manager.task.interval.ms: Is
> > that
> > > the
> > > > > > > > amount of
> > > > > > > > > > > > time to
> > > > > > > > > > > > > > back off when there is no work to do? If so,
> > perhaps
> > > it
> > > > > can
> > > > > > > be
> > > > > > > > > > renamed
> > > > > > > > > > > > as
> > > > > > > > > > > > > > backoff.ms.
> > > > > > > > > > > > > > 5103.5 Are rlm_process_interval_ms and
> > > > > rlm_retry_interval_ms
> > > > > > > > > > configs?
> > > > > > > > > > > > If
> > > > > > > > > > > > > > so, they need to be listed in this section.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5104. "RLM maintains a bounded cache(possibly LRU)
> > > of the
> > > > > > > index
> > > > > > > > > > files
> > > > > > > > > > > > of
> > > > > > > > > > > > > > remote log segments to avoid multiple index fetches
> > > from
> > > > > the
> > > > > > > > remote
> > > > > > > > > > > > > > storage." Is the RLM in memory or on disk? If on
> > > disk,
> > > > > where
> > > > > > > > is it
> > > > > > > > > > > > stored?
> > > > > > > > > > > > > > Do we need a configuration to bound the size?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5105. The KIP uses local-log-start-offset and
> > > Earliest
> > > > > Local
> > > > > > > > > > Offset in
> > > > > > > > > > > > > > different places. It would be useful to standardize
> > > the
> > > > > > > > > > terminology.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5106. The section on "In BuildingRemoteLogAux
> > > state". It
> > > > > > > > listed two
> > > > > > > > > > > > options
> > > > > > > > > > > > > > without saying which option is chosen.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5107. Follower to leader transition: It has step 2,
> > > but
> > > > > not
> > > > > > > > step 1.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5108. If a consumer fetches from the remote data
> > and
> > > the
> > > > > > > remote
> > > > > > > > > > > > storage is
> > > > > > > > > > > > > > not available, what error code is used in the fetch
> > > > > response?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5109. "ListOffsets: For timestamps >= 0, it returns
> > > the
> > > > > first
> > > > > > > > > > message
> > > > > > > > > > > > > > offset whose timestamp is >= to the given timestamp
> > > in
> > > > > the
> > > > > > > > request.
> > > > > > > > > > > > That
> > > > > > > > > > > > > > means it checks in remote log time indexes first,
> > > after
> > > > > which
> > > > > > > > > > local log
> > > > > > > > > > > > > > time indexes are checked." Could you document which
> > > > > method in
> > > > > > > > RLMM
> > > > > > > > > > is
> > > > > > > > > > > > used
> > > > > > > > > > > > > > for this?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5110. Stopreplica: "it sets all the remote log
> > > segment
> > > > > > > > metadata of
> > > > > > > > > > that
> > > > > > > > > > > > > > partition with a delete marker and publishes them
> > to
> > > > > RLMM."
> > > > > > > > This
> > > > > > > > > > seems
> > > > > > > > > > > > > > outdated given the new topic deletion logic.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5111. "RLM follower fetches the earliest offset for
> > > the
> > > > > > > > earliest
> > > > > > > > > > leader
> > > > > > > > > > > > > > epoch by calling
> > > RLMM.earliestLogOffset(TopicPartition
> > > > > > > > > > topicPartition,
> > > > > > > > > > > > int
> > > > > > > > > > > > > > leaderEpoch) and updates that as the log start
> > > offset."
> > > > > Do we
> > > > > > > > need
> > > > > > > > > > that
> > > > > > > > > > > > > > since replication propagates logStartOffset
> > already?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5112. Is the default maxWaitMs of 500ms enough for
> > > > > fetching
> > > > > > > > from
> > > > > > > > > > remote
> > > > > > > > > > > > > > storage?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5113. "Committed offsets can be stored in a local
> > > file to
> > > > > > > avoid
> > > > > > > > > > > > reading the
> > > > > > > > > > > > > > messages again when a broker is restarted." Could
> > you
> > > > > > > describe
> > > > > > > > the
> > > > > > > > > > > > format
> > > > > > > > > > > > > > and the location of the file? Also, could the same
> > > > > message be
> > > > > > > > > > > > processed by
> > > > > > > > > > > > > > RLMM again after broker restart? If so, how do we
> > > handle
> > > > > > > that?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5114. Message format
> > > > > > > > > > > > > > 5114.1 There are two records named
> > > > > > > > RemoteLogSegmentMetadataRecord
> > > > > > > > > > with
> > > > > > > > > > > > > > apiKey 0 and 1.
> > > > > > > > > > > > > > 5114.2 RemoteLogSegmentMetadataRecord: Could we
> > > document
> > > > > > > > whether
> > > > > > > > > > > > endOffset
> > > > > > > > > > > > > > is inclusive/exclusive?
> > > > > > > > > > > > > > 5114.3 RemoteLogSegmentMetadataRecord: Could you
> > > explain
> > > > > > > > > > LeaderEpoch a
> > > > > > > > > > > > bit
> > > > > > > > > > > > > > more? Is that the epoch of the leader when it
> > copies
> > > the
> > > > > > > > segment to
> > > > > > > > > > > > remote
> > > > > > > > > > > > > > storage? Also, how will this field be used?
> > > > > > > > > > > > > > 5114.4 EventTimestamp: Could you explain this a bit
> > > more?
> > > > > > > Each
> > > > > > > > > > record
> > > > > > > > > > > > in
> > > > > > > > > > > > > > Kafka already has a timestamp field. Could we just
> > > use
> > > > > that?
> > > > > > > > > > > > > > 5114.5 SegmentSizeInBytes: Could this just be
> > int32?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5115. RemoteLogCleaner(RLC): This could be confused
> > > with
> > > > > the
> > > > > > > > log
> > > > > > > > > > > > cleaner
> > > > > > > > > > > > > > for compaction. Perhaps it can be renamed to sth
> > like
> > > > > > > > > > > > > > RemotePartitionRemover.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5116. "RLC receives the delete_partition_marked and
> > > > > processes
> > > > > > > > it
> > > > > > > > > > if it
> > > > > > > > > > > > is
> > > > > > > > > > > > > > not yet processed earlier." How does it know
> > whether
> > > > > > > > > > > > > > delete_partition_marked has been processed earlier?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5117. Should we add a new MessageFormatter to read
> > > the
> > > > > tier
> > > > > > > > > > metadata
> > > > > > > > > > > > topic?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5118. "Maximum remote log reader thread pool task
> > > queue
> > > > > size.
> > > > > > > > If
> > > > > > > > > > the
> > > > > > > > > > > > task
> > > > > > > > > > > > > > queue is full, broker will stop reading remote log
> > > > > segments."
> > > > > > > > What
> > > > > > > > > > do
> > > > > > > > > > > > we
> > > > > > > > > > > > > > return to the fetch request in this case?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5119. It would be useful to list all things not
> > > > > supported in
> > > > > > > > the
> > > > > > > > > > first
> > > > > > > > > > > > > > version in a Future work or Limitations section.
> > For
> > > > > example,
> > > > > > > > > > compacted
> > > > > > > > > > > > > > topic, JBOD, changing remote.log.storage.enable
> > from
> > > > > true to
> > > > > > > > false,
> > > > > > > > > > > > etc.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Jun
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > On Tue, Oct 27, 2020 at 5:57 PM Kowshik Prakasam <
> > > > > > > > > > > > kprakasam@confluent.io>
> > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Hi Satish,
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Thanks for the updates to the KIP. Here are my
> > > first
> > > > > batch
> > > > > > > of
> > > > > > > > > > > > > > > comments/suggestions on the latest version of the
> > > KIP.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5012. In the RemoteStorageManager interface,
> > there
> > > is
> > > > > an
> > > > > > > API
> > > > > > > > > > defined
> > > > > > > > > > > > for
> > > > > > > > > > > > > > > each file type. For example, fetchOffsetIndex,
> > > > > > > > > > fetchTimestampIndex
> > > > > > > > > > > > etc. To
> > > > > > > > > > > > > > > avoid the duplication, I'd suggest we can instead
> > > have
> > > > > a
> > > > > > > > FileType
> > > > > > > > > > > > enum and
> > > > > > > > > > > > > > > a common get API based on the FileType.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5013. There are some references to the Google doc
> > > in
> > > > > the
> > > > > > > > KIP. I
> > > > > > > > > > > > wasn't sure
> > > > > > > > > > > > > > > if the Google doc is expected to be in sync with
> > > the
> > > > > > > > contents of
> > > > > > > > > > the
> > > > > > > > > > > > wiki.
> > > > > > > > > > > > > > > Going forward, it seems easier if just the KIP is
> > > > > > > maintained
> > > > > > > > as
> > > > > > > > > > the
> > > > > > > > > > > > source
> > > > > > > > > > > > > > > of truth. In this regard, could you please move
> > > all the
> > > > > > > > > > references
> > > > > > > > > > > > to the
> > > > > > > > > > > > > > > Google doc, maybe to a separate References
> > section
> > > at
> > > > > the
> > > > > > > > bottom
> > > > > > > > > > of
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > KIP?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5014. There are some TODO sections in the KIP.
> > > Would
> > > > > these
> > > > > > > be
> > > > > > > > > > filled
> > > > > > > > > > > > up in
> > > > > > > > > > > > > > > future iterations?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5015. Under "Topic deletion lifecycle", I'm
> > trying
> > > to
> > > > > > > > understand
> > > > > > > > > > why
> > > > > > > > > > > > do we
> > > > > > > > > > > > > > > need delete_partition_marked as well as the
> > > > > > > > > > delete_partition_started
> > > > > > > > > > > > > > > messages. I couldn't spot a drawback if supposing
> > > we
> > > > > > > > simplified
> > > > > > > > > > the
> > > > > > > > > > > > design
> > > > > > > > > > > > > > > such that the controller would only write
> > > > > > > > > > delete_partition_started
> > > > > > > > > > > > message,
> > > > > > > > > > > > > > > and RemoteLogCleaner (RLC) instance picks it up
> > for
> > > > > > > > processing.
> > > > > > > > > > What
> > > > > > > > > > > > am I
> > > > > > > > > > > > > > > missing?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5016. Under "Topic deletion lifecycle", step (4)
> > is
> > > > > > > > mentioned as
> > > > > > > > > > > > "RLC gets
> > > > > > > > > > > > > > > all the remote log segments for the partition and
> > > each
> > > > > of
> > > > > > > > these
> > > > > > > > > > > > remote log
> > > > > > > > > > > > > > > segments is deleted with the next steps.". Since
> > > the
> > > > > RLC
> > > > > > > > instance
> > > > > > > > > > > > runs on
> > > > > > > > > > > > > > > each tier topic partition leader, how does the
> > RLC
> > > > > then get
> > > > > > > > the
> > > > > > > > > > list
> > > > > > > > > > > > of
> > > > > > > > > > > > > > > remote log segments to be deleted? It will be
> > > useful
> > > > > to add
> > > > > > > > that
> > > > > > > > > > > > detail to
> > > > > > > > > > > > > > > the KIP.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5017. Under "Public Interfaces -> Configs", there
> > > is a
> > > > > line
> > > > > > > > > > > > mentioning "We
> > > > > > > > > > > > > > > will support flipping remote.log.storage.enable
> > in
> > > next
> > > > > > > > > > versions."
> > > > > > > > > > > > It will
> > > > > > > > > > > > > > > be useful to mention this in the "Future Work"
> > > section
> > > > > of
> > > > > > > > the KIP
> > > > > > > > > > > > too.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5018. The KIP introduces a number of
> > configuration
> > > > > > > > parameters. It
> > > > > > > > > > > > will be
> > > > > > > > > > > > > > > useful to mention in the KIP if the user should
> > > assume
> > > > > > > these
> > > > > > > > as
> > > > > > > > > > > > static
> > > > > > > > > > > > > > > configuration in the server.properties file, or
> > > dynamic
> > > > > > > > > > > > configuration which
> > > > > > > > > > > > > > > can be modified without restarting the broker.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5019.  Maybe this is planned as a future update
> > to
> > > the
> > > > > KIP,
> > > > > > > > but I
> > > > > > > > > > > > thought
> > > > > > > > > > > > > > > I'd mention it here. Could you please add details
> > > to
> > > > > the
> > > > > > > KIP
> > > > > > > > on
> > > > > > > > > > why
> > > > > > > > > > > > RocksDB
> > > > > > > > > > > > > > > was chosen as the default cache implementation of
> > > > > RLMM, and
> > > > > > > > how
> > > > > > > > > > it
> > > > > > > > > > > > is going
> > > > > > > > > > > > > > > to be used? Were alternatives
> > compared/considered?
> > > For
> > > > > > > > example,
> > > > > > > > > > it
> > > > > > > > > > > > would be
> > > > > > > > > > > > > > > useful to explain/evaluate the following: 1)
> > > > > debuggability
> > > > > > > > of the
> > > > > > > > > > > > RocksDB
> > > > > > > > > > > > > > > JNI interface, 2) performance, 3) portability
> > > across
> > > > > > > > platforms
> > > > > > > > > > and 4)
> > > > > > > > > > > > > > > interface parity of RocksDB’s JNI api with it's
> > > > > underlying
> > > > > > > > C/C++
> > > > > > > > > > api.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5020. Following up on (5019), for the RocksDB
> > > cache, it
> > > > > > > will
> > > > > > > > be
> > > > > > > > > > > > useful to
> > > > > > > > > > > > > > > explain the relationship/mapping between the
> > > following
> > > > > in
> > > > > > > the
> > > > > > > > > > KIP:
> > > > > > > > > > > > 1) # of
> > > > > > > > > > > > > > > tiered partitions, 2) # of partitions of metadata
> > > topic
> > > > > > > > > > > > > > > __remote_log_metadata and 3) # of RocksDB
> > > instances.
> > > > > i.e.
> > > > > > > is
> > > > > > > > the
> > > > > > > > > > > > plan to
> > > > > > > > > > > > > > > have a RocksDB instance per tiered partition, or
> > > per
> > > > > > > metadata
> > > > > > > > > > topic
> > > > > > > > > > > > > > > partition, or just 1 for per broker?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5021. I was looking at the implementation
> > > prototype (PR
> > > > > > > link:
> > > > > > > > > > > > > > > https://github.com/apache/kafka/pull/7561). It
> > > seems
> > > > > that
> > > > > > > a
> > > > > > > > > > boolean
> > > > > > > > > > > > > > > attribute is being introduced into the Log layer
> > to
> > > > > check
> > > > > > > if
> > > > > > > > > > remote
> > > > > > > > > > > > log
> > > > > > > > > > > > > > > capability is enabled. While the boolean
> > footprint
> > > is
> > > > > small
> > > > > > > > at
> > > > > > > > > > the
> > > > > > > > > > > > moment,
> > > > > > > > > > > > > > > this can easily grow in the future and become
> > > harder to
> > > > > > > > > > > > > > > test/maintain, considering that the Log layer is
> > > > > already
> > > > > > > > pretty
> > > > > > > > > > > > complex. We
> > > > > > > > > > > > > > > should start thinking about how to manage such
> > > changes
> > > > > to
> > > > > > > > the Log
> > > > > > > > > > > > layer
> > > > > > > > > > > > > > > (for the purpose of improved testability, better
> > > > > separation
> > > > > > > > of
> > > > > > > > > > > > concerns and
> > > > > > > > > > > > > > > readability). One proposal I have is to take a
> > step
> > > > > back
> > > > > > > and
> > > > > > > > > > define a
> > > > > > > > > > > > > > > higher level Log interface. Then, the Broker code
> > > can
> > > > > be
> > > > > > > > changed
> > > > > > > > > > to
> > > > > > > > > > > > use
> > > > > > > > > > > > > > > this interface. It can be changed such that only
> > a
> > > > > handle
> > > > > > > to
> > > > > > > > the
> > > > > > > > > > > > interface
> > > > > > > > > > > > > > > is exposed to other components (such as
> > LogCleaner,
> > > > > > > > > > ReplicaManager
> > > > > > > > > > > > etc.)
> > > > > > > > > > > > > > > and not the underlying Log object. This approach
> > > keeps
> > > > > the
> > > > > > > > user
> > > > > > > > > > of
> > > > > > > > > > > > the Log
> > > > > > > > > > > > > > > layer agnostic of the whereabouts of the data.
> > > > > Underneath
> > > > > > > the
> > > > > > > > > > > > interface,
> > > > > > > > > > > > > > > the implementing classes can completely separate
> > > local
> > > > > log
> > > > > > > > > > > > capabilities
> > > > > > > > > > > > > > > from the remote log. For example, the Log class
> > > can be
> > > > > > > > > > simplified to
> > > > > > > > > > > > only
> > > > > > > > > > > > > > > manage logic surrounding local log segments and
> > > > > metadata.
> > > > > > > > > > > > Additionally, a
> > > > > > > > > > > > > > > wrapper class can be provided (implementing the
> > > higher
> > > > > > > level
> > > > > > > > Log
> > > > > > > > > > > > interface)
> > > > > > > > > > > > > > > which will contain any/all logic surrounding
> > tiered
> > > > > data.
> > > > > > > The
> > > > > > > > > > wrapper
> > > > > > > > > > > > > > > class will wrap around an instance of the Log
> > class
> > > > > > > > delegating
> > > > > > > > > > the
> > > > > > > > > > > > local
> > > > > > > > > > > > > > > log logic to it. Finally, a handle to the wrapper
> > > > > class can
> > > > > > > > be
> > > > > > > > > > > > exposed to
> > > > > > > > > > > > > > > the other components wherever they need a handle
> > > to the
> > > > > > > > higher
> > > > > > > > > > level
> > > > > > > > > > > > Log
> > > > > > > > > > > > > > > interface.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Cheers,
> > > > > > > > > > > > > > > Kowshik
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > On Mon, Oct 26, 2020 at 9:52 PM Satish Duggana <
> > > > > > > > > > > > satish.duggana@gmail.com>
> > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Hi,
> > > > > > > > > > > > > > > > KIP is updated with 1) topic deletion lifecycle
> > > and
> > > > > its
> > > > > > > > related
> > > > > > > > > > > > items
> > > > > > > > > > > > > > > > 2) Protocol changes(mainly related to
> > > ListOffsets)
> > > > > and
> > > > > > > > other
> > > > > > > > > > minor
> > > > > > > > > > > > > > > > changes.
> > > > > > > > > > > > > > > > Please go through them and let us know your
> > > comments.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > Satish.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > On Mon, Sep 28, 2020 at 9:10 PM Satish Duggana
> > <
> > > > > > > > > > > > satish.duggana@gmail.com
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Hi Dhruvil,
> > > > > > > > > > > > > > > > > Thanks for looking into the KIP and sending
> > > your
> > > > > > > > comments.
> > > > > > > > > > Sorry
> > > > > > > > > > > > for
> > > > > > > > > > > > > > > > > the late reply, missed it in the mail thread.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 1. Could you describe how retention would
> > work
> > > with
> > > > > > > this
> > > > > > > > KIP
> > > > > > > > > > and
> > > > > > > > > > > > which
> > > > > > > > > > > > > > > > > threads are responsible for driving this
> > work?
> > > I
> > > > > > > believe
> > > > > > > > > > there
> > > > > > > > > > > > are 3
> > > > > > > > > > > > > > > > kinds
> > > > > > > > > > > > > > > > > of retention processes we are looking at:
> > > > > > > > > > > > > > > > >   (a) Regular retention for data in tiered
> > > storage
> > > > > as
> > > > > > > per
> > > > > > > > > > > > configured `
> > > > > > > > > > > > > > > > > retention.ms` / `retention.bytes`.
> > > > > > > > > > > > > > > > >   (b) Local retention for data in local
> > > storage as
> > > > > per
> > > > > > > > > > > > configured `
> > > > > > > > > > > > > > > > > local.log.retention.ms` /
> > > > > `local.log.retention.bytes`
> > > > > > > > > > > > > > > > >   (c) Possibly regular retention for data in
> > > local
> > > > > > > > storage,
> > > > > > > > > > if
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > > tiering
> > > > > > > > > > > > > > > > > task is lagging or for data that is below the
> > > log
> > > > > start
> > > > > > > > > > offset.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Local log retention is done by the existing
> > log
> > > > > cleanup
> > > > > > > > > > tasks.
> > > > > > > > > > > > These
> > > > > > > > > > > > > > > > > are not done for segments that are not yet
> > > copied
> > > > > to
> > > > > > > > remote
> > > > > > > > > > > > storage.
> > > > > > > > > > > > > > > > > Remote log cleanup is done by the leader
> > > > > partition’s
> > > > > > > > RLMTask.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 2. When does a segment become eligible to be
> > > > > tiered? Is
> > > > > > > > it as
> > > > > > > > > > > > soon as
> > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > segment is rolled and the end offset is less
> > > than
> > > > > the
> > > > > > > > last
> > > > > > > > > > stable
> > > > > > > > > > > > > > > offset
> > > > > > > > > > > > > > > > as
> > > > > > > > > > > > > > > > > mentioned in the KIP? I wonder if we need to
> > > > > consider
> > > > > > > > other
> > > > > > > > > > > > parameters
> > > > > > > > > > > > > > > > too,
> > > > > > > > > > > > > > > > > like the highwatermark so that we are
> > > guaranteed
> > > > > that
> > > > > > > > what
> > > > > > > > > > we are
> > > > > > > > > > > > > > > tiering
> > > > > > > > > > > > > > > > > has been committed to the log and accepted by
> > > the
> > > > > ISR.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > AFAIK, last stable offset is always <=
> > > > > highwatermark.
> > > > > > > > This
> > > > > > > > > > will
> > > > > > > > > > > > make
> > > > > > > > > > > > > > > > > sure we are always tiering the message
> > segments
> > > > > which
> > > > > > > > have
> > > > > > > > > > been
> > > > > > > > > > > > > > > > > accepted by ISR and transactionally
> > completed.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 3. The section on "Follower Fetch Scenarios"
> > is
> > > > > useful
> > > > > > > > but
> > > > > > > > > > is a
> > > > > > > > > > > > bit
> > > > > > > > > > > > > > > > > difficult to parse at the moment. It would be
> > > > > useful to
> > > > > > > > > > > > summarize the
> > > > > > > > > > > > > > > > > changes we need in the ReplicaFetcher.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > It may become difficult for users to
> > > read/follow
> > > > > if we
> > > > > > > > add
> > > > > > > > > > code
> > > > > > > > > > > > changes
> > > > > > > > > > > > > > > > here.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 4. Related to the above, it's a bit unclear
> > > how we
> > > > > are
> > > > > > > > > > planning
> > > > > > > > > > > > on
> > > > > > > > > > > > > > > > > restoring the producer state for a new
> > replica.
> > > > > Could
> > > > > > > you
> > > > > > > > > > expand
> > > > > > > > > > > > on
> > > > > > > > > > > > > > > that?
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > It is mentioned in the KIP
> > > > > BuildingRemoteLogAuxState is
> > > > > > > > > > > > introduced to
> > > > > > > > > > > > > > > > > build the state like leader epoch sequence
> > and
> > > > > producer
> > > > > > > > > > snapshots
> > > > > > > > > > > > > > > > > before it starts fetching the data from the
> > > > > leader. We
> > > > > > > > will
> > > > > > > > > > make
> > > > > > > > > > > > it
> > > > > > > > > > > > > > > > > clear in the KIP.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 5. Similarly, it would be worth summarizing
> > the
> > > > > > > behavior
> > > > > > > > on
> > > > > > > > > > > > unclean
> > > > > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > > election. There are several scenarios to
> > > consider
> > > > > here:
> > > > > > > > data
> > > > > > > > > > > > loss from
> > > > > > > > > > > > > > > > > local log, data loss from remote log, data
> > loss
> > > > > from
> > > > > > > > metadata
> > > > > > > > > > > > topic,
> > > > > > > > > > > > > > > etc.
> > > > > > > > > > > > > > > > > It's worth describing these in detail.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > We mentioned the cases about unclean leader
> > > > > election in
> > > > > > > > the
> > > > > > > > > > > > follower
> > > > > > > > > > > > > > > > > fetch scenarios.
> > > > > > > > > > > > > > > > > If there are errors while fetching data from
> > > remote
> > > > > > > > store or
> > > > > > > > > > > > metadata
> > > > > > > > > > > > > > > > > store, it will work the same way as it works
> > > with
> > > > > local
> > > > > > > > log.
> > > > > > > > > > It
> > > > > > > > > > > > > > > > > returns the error back to the caller. Please
> > > let us
> > > > > > > know
> > > > > > > > if
> > > > > > > > > > I am
> > > > > > > > > > > > > > > > > missing your point here.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 7. For a READ_COMMITTED FetchRequest, how do
> > we
> > > > > > > retrieve
> > > > > > > > and
> > > > > > > > > > > > return the
> > > > > > > > > > > > > > > > > aborted transaction metadata?
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > When a fetch for a remote log is accessed, we
> > > will
> > > > > > > fetch
> > > > > > > > > > aborted
> > > > > > > > > > > > > > > > > transactions along with the segment if it is
> > > not
> > > > > found
> > > > > > > > in the
> > > > > > > > > > > > local
> > > > > > > > > > > > > > > > > index cache. This includes the case of
> > > transaction
> > > > > > > index
> > > > > > > > not
> > > > > > > > > > > > existing
> > > > > > > > > > > > > > > > > in the remote log segment. That means, the
> > > cache
> > > > > entry
> > > > > > > > can be
> > > > > > > > > > > > empty or
> > > > > > > > > > > > > > > > > have a list of aborted transactions.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 8. The `LogSegmentData` class assumes that we
> > > have
> > > > > a
> > > > > > > log
> > > > > > > > > > segment,
> > > > > > > > > > > > > > > offset
> > > > > > > > > > > > > > > > > index, time index, transaction index,
> > producer
> > > > > snapshot
> > > > > > > > and
> > > > > > > > > > > > leader
> > > > > > > > > > > > > > > epoch
> > > > > > > > > > > > > > > > > index. How do we deal with cases where we do
> > > not
> > > > > have
> > > > > > > > one or
> > > > > > > > > > > > more of
> > > > > > > > > > > > > > > > these?
> > > > > > > > > > > > > > > > > For example, we may not have a transaction
> > > index or
> > > > > > > > producer
> > > > > > > > > > > > snapshot
> > > > > > > > > > > > > > > > for a
> > > > > > > > > > > > > > > > > particular segment. The former is optional,
> > > and the
> > > > > > > > latter is
> > > > > > > > > > > > only kept
> > > > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > > up to the 3 latest segments.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > This is a good point,  we discussed this in
> > the
> > > > > last
> > > > > > > > meeting.
> > > > > > > > > > > > > > > > > Transaction index is optional and we will
> > copy
> > > them
> > > > > > > only
> > > > > > > > if
> > > > > > > > > > it
> > > > > > > > > > > > exists.
> > > > > > > > > > > > > > > > > We want to keep all the producer snapshots at
> > > each
> > > > > log
> > > > > > > > > > segment
> > > > > > > > > > > > rolling
> > > > > > > > > > > > > > > > > and they can be removed if the log copying is
> > > > > > > successful
> > > > > > > > and
> > > > > > > > > > it
> > > > > > > > > > > > still
> > > > > > > > > > > > > > > > > maintains the existing latest 3 segments, We
> > > only
> > > > > > > delete
> > > > > > > > the
> > > > > > > > > > > > producer
> > > > > > > > > > > > > > > > > snapshots which have been copied to remote
> > log
> > > > > segments
> > > > > > > > on
> > > > > > > > > > > > leader.
> > > > > > > > > > > > > > > > > Follower will keep the log segments beyond
> > the
> > > > > segments
> > > > > > > > which
> > > > > > > > > > > > have not
> > > > > > > > > > > > > > > > > been copied to remote storage. We will update
> > > the
> > > > > KIP
> > > > > > > > with
> > > > > > > > > > these
> > > > > > > > > > > > > > > > > details.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > > Satish.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > On Thu, Sep 17, 2020 at 1:47 AM Dhruvil Shah
> > <
> > > > > > > > > > > > dhruvil@confluent.io>
> > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > Hi Satish, Harsha,
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > Thanks for the KIP. Few questions below:
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > 1. Could you describe how retention would
> > > work
> > > > > with
> > > > > > > > this
> > > > > > > > > > KIP
> > > > > > > > > > > > and
> > > > > > > > > > > > > > > which
> > > > > > > > > > > > > > > > > > threads are responsible for driving this
> > > work? I
> > > > > > > > believe
> > > > > > > > > > there
> > > > > > > > > > > > are 3
> > > > > > > > > > > > > > > > kinds
> > > > > > > > > > > > > > > > > > of retention processes we are looking at:
> > > > > > > > > > > > > > > > > >   (a) Regular retention for data in tiered
> > > > > storage as
> > > > > > > > per
> > > > > > > > > > > > configured
> > > > > > > > > > > > > > > `
> > > > > > > > > > > > > > > > > > retention.ms` / `retention.bytes`.
> > > > > > > > > > > > > > > > > >   (b) Local retention for data in local
> > > storage
> > > > > as
> > > > > > > per
> > > > > > > > > > > > configured `
> > > > > > > > > > > > > > > > > > local.log.retention.ms` /
> > > > > > > `local.log.retention.bytes`
> > > > > > > > > > > > > > > > > >   (c) Possibly regular retention for data
> > in
> > > > > local
> > > > > > > > > > storage, if
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > > tiering
> > > > > > > > > > > > > > > > > > task is lagging or for data that is below
> > > the log
> > > > > > > start
> > > > > > > > > > offset.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > 2. When does a segment become eligible to
> > be
> > > > > tiered?
> > > > > > > > Is it
> > > > > > > > > > as
> > > > > > > > > > > > soon as
> > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > segment is rolled and the end offset is
> > less
> > > > > than the
> > > > > > > > last
> > > > > > > > > > > > stable
> > > > > > > > > > > > > > > > offset as
> > > > > > > > > > > > > > > > > > mentioned in the KIP? I wonder if we need
> > to
> > > > > consider
> > > > > > > > other
> > > > > > > > > > > > > > > parameters
> > > > > > > > > > > > > > > > too,
> > > > > > > > > > > > > > > > > > like the highwatermark so that we are
> > > guaranteed
> > > > > that
> > > > > > > > what
> > > > > > > > > > we
> > > > > > > > > > > > are
> > > > > > > > > > > > > > > > tiering
> > > > > > > > > > > > > > > > > > has been committed to the log and accepted
> > > by the
> > > > > > > ISR.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > 3. The section on "Follower Fetch
> > Scenarios"
> > > is
> > > > > > > useful
> > > > > > > > but
> > > > > > > > > > is
> > > > > > > > > > > > a bit
> > > > > > > > > > > > > > > > > > difficult to parse at the moment. It would
> > be
> > > > > useful
> > > > > > > to
> > > > > > > > > > > > summarize the
> > > > > > > > > > > > > > > > > > changes we need in the ReplicaFetcher.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > 4. Related to the above, it's a bit unclear
> > > how
> > > > > we
> > > > > > > are
> > > > > > > > > > > > planning on
> > > > > > > > > > > > > > > > > > restoring the producer state for a new
> > > replica.
> > > > > Could
> > > > > > > > you
> > > > > > > > > > > > expand on
> > > > > > > > > > > > > > > > that?
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > 5. Similarly, it would be worth summarizing
> > > the
> > > > > > > > behavior on
> > > > > > > > > > > > unclean
> > > > > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > > > election. There are several scenarios to
> > > consider
> > > > > > > here:
> > > > > > > > > > data
> > > > > > > > > > > > loss
> > > > > > > > > > > > > > > from
> > > > > > > > > > > > > > > > > > local log, data loss from remote log, data
> > > loss
> > > > > from
> > > > > > > > > > metadata
> > > > > > > > > > > > topic,
> > > > > > > > > > > > > > > > etc.
> > > > > > > > > > > > > > > > > > It's worth describing these in detail.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > 6. It would be useful to add details about
> > > how we
> > > > > > > plan
> > > > > > > > on
> > > > > > > > > > using
> > > > > > > > > > > > > > > > RocksDB in
> > > > > > > > > > > > > > > > > > the default implementation of
> > > > > > > > `RemoteLogMetadataManager`.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > 7. For a READ_COMMITTED FetchRequest, how
> > do
> > > we
> > > > > > > > retrieve
> > > > > > > > > > and
> > > > > > > > > > > > return
> > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > aborted transaction metadata?
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > 8. The `LogSegmentData` class assumes that
> > we
> > > > > have a
> > > > > > > > log
> > > > > > > > > > > > segment,
> > > > > > > > > > > > > > > > offset
> > > > > > > > > > > > > > > > > > index, time index, transaction index,
> > > producer
> > > > > > > > snapshot and
> > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > epoch
> > > > > > > > > > > > > > > > > > index. How do we deal with cases where we
> > do
> > > not
> > > > > have
> > > > > > > > one
> > > > > > > > > > or
> > > > > > > > > > > > more of
> > > > > > > > > > > > > > > > these?
> > > > > > > > > > > > > > > > > > For example, we may not have a transaction
> > > index
> > > > > or
> > > > > > > > > > producer
> > > > > > > > > > > > snapshot
> > > > > > > > > > > > > > > > for a
> > > > > > > > > > > > > > > > > > particular segment. The former is optional,
> > > and
> > > > > the
> > > > > > > > latter
> > > > > > > > > > is
> > > > > > > > > > > > only
> > > > > > > > > > > > > > > > kept for
> > > > > > > > > > > > > > > > > > up to the 3 latest segments.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > > > Dhruvil
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > On Mon, Sep 7, 2020 at 6:54 PM Harsha Ch <
> > > > > > > > > > harsha.ch@gmail.com>
> > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Hi All,
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > We are all working through the last
> > meeting
> > > > > > > feedback.
> > > > > > > > > > I'll
> > > > > > > > > > > > cancel
> > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > tomorrow 's meeting and we can meanwhile
> > > > > continue
> > > > > > > our
> > > > > > > > > > > > discussion in
> > > > > > > > > > > > > > > > mailing
> > > > > > > > > > > > > > > > > > > list. We can start the regular meeting
> > from
> > > > > next
> > > > > > > week
> > > > > > > > > > > > onwards.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Harsha
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > On Fri, Sep 04, 2020 at 8:41 AM, Satish
> > > > > Duggana <
> > > > > > > > > > > > > > > > satish.duggana@gmail.com
> > > > > > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > Hi Jun,
> > > > > > > > > > > > > > > > > > > > Thanks for your thorough review and
> > > comments.
> > > > > > > > Please
> > > > > > > > > > find
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > > inline
> > > > > > > > > > > > > > > > > > > > replies below.
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > 600. The topic deletion logic needs
> > more
> > > > > details.
> > > > > > > > > > > > > > > > > > > > 600.1 The KIP mentions "The controller
> > > > > considers
> > > > > > > > the
> > > > > > > > > > topic
> > > > > > > > > > > > > > > > partition is
> > > > > > > > > > > > > > > > > > > > deleted only when it determines that
> > > there
> > > > > are no
> > > > > > > > log
> > > > > > > > > > > > segments
> > > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > that
> > > > > > > > > > > > > > > > > > > > topic partition by using RLMM". How is
> > > this
> > > > > done?
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > It uses RLMM#listSegments() returns all
> > > the
> > > > > > > > segments
> > > > > > > > > > for
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > given
> > > > > > > > > > > > > > > > topic
> > > > > > > > > > > > > > > > > > > > partition.
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > 600.2 "If the delete option is enabled
> > > then
> > > > > the
> > > > > > > > leader
> > > > > > > > > > > > will stop
> > > > > > > > > > > > > > > > RLM task
> > > > > > > > > > > > > > > > > > > > and stop processing and it sets all the
> > > > > remote
> > > > > > > log
> > > > > > > > > > segment
> > > > > > > > > > > > > > > > metadata of
> > > > > > > > > > > > > > > > > > > > that partition with a delete marker and
> > > > > publishes
> > > > > > > > them
> > > > > > > > > > to
> > > > > > > > > > > > RLMM."
> > > > > > > > > > > > > > > We
> > > > > > > > > > > > > > > > > > > > discussed this earlier. When a topic is
> > > being
> > > > > > > > deleted,
> > > > > > > > > > > > there may
> > > > > > > > > > > > > > > > not be a
> > > > > > > > > > > > > > > > > > > > leader for the deleted partition.
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > This is a good point. As suggested in
> > the
> > > > > > > meeting,
> > > > > > > > we
> > > > > > > > > > will
> > > > > > > > > > > > add a
> > > > > > > > > > > > > > > > separate
> > > > > > > > > > > > > > > > > > > > section for topic/partition deletion
> > > > > lifecycle
> > > > > > > and
> > > > > > > > this
> > > > > > > > > > > > scenario
> > > > > > > > > > > > > > > > will be
> > > > > > > > > > > > > > > > > > > > addressed.
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > 601. Unclean leader election
> > > > > > > > > > > > > > > > > > > > 601.1 Scenario 1: new empty follower
> > > > > > > > > > > > > > > > > > > > After step 1, the follower restores up
> > to
> > > > > offset
> > > > > > > > 3. So
> > > > > > > > > > why
> > > > > > > > > > > > does
> > > > > > > > > > > > > > > it
> > > > > > > > > > > > > > > > have
> > > > > > > > > > > > > > > > > > > > LE-2 <
> > > > > https://issues.apache.org/jira/browse/LE-2
> > > > > > > >
> > > > > > > > at
> > > > > > > > > > > > offset 5?
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > Nice catch. It was showing the leader
> > > epoch
> > > > > > > fetched
> > > > > > > > > > from
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > > > > storage. It should be shown with the
> > > > > truncated
> > > > > > > till
> > > > > > > > > > offset
> > > > > > > > > > > > 3.
> > > > > > > > > > > > > > > > Updated the
> > > > > > > > > > > > > > > > > > > > KIP.
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > 601.2 senario 5: After Step 3, leader A
> > > has
> > > > > > > > > > inconsistent
> > > > > > > > > > > > data
> > > > > > > > > > > > > > > > between its
> > > > > > > > > > > > > > > > > > > > local and the tiered data. For example.
> > > > > offset 3
> > > > > > > > has
> > > > > > > > > > msg 3
> > > > > > > > > > > > LE-0
> > > > > > > > > > > > > > > > <https://issues.apache.org/jira/browse/LE-0>
> > > > > locally,
> > > > > > > > > > > > > > > > > > > > but msg 5 LE-1 <
> > > > > > > > > > https://issues.apache.org/jira/browse/LE-1>
> > > > > > > > > > > > in
> > > > > > > > > > > > > > > > the remote store. While it's ok for the unclean
> > > > > leader
> > > > > > > > > > > > > > > > > > > > to lose data, it should still return
> > > > > consistent
> > > > > > > > data,
> > > > > > > > > > > > whether
> > > > > > > > > > > > > > > it's
> > > > > > > > > > > > > > > > from
> > > > > > > > > > > > > > > > > > > > the local or the remote store.
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > There is no inconsistency here as LE-0
> > > > > > > > > > > > > > > > <https://issues.apache.org/jira/browse/LE-0>
> > > > > offsets are
> > > > > > > > [0,
> > > > > > > > > > 4]
> > > > > > > > > > > > and LE-2
> > > > > > > > > > > > > > > > <https://issues.apache.org/jira/browse/LE-2>:
> > > > > > > > > > > > > > > > > > > > [5, ]. It will always get the right
> > > records
> > > > > for
> > > > > > > the
> > > > > > > > > > given
> > > > > > > > > > > > offset
> > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > > leader epoch. In case of remote, RSM is
> > > > > invoked
> > > > > > > to
> > > > > > > > get
> > > > > > > > > > the
> > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > log
> > > > > > > > > > > > > > > > > > > > segment that contains the given offset
> > > with
> > > > > the
> > > > > > > > leader
> > > > > > > > > > > > epoch.
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > 601.4 It seems that retention is based
> > on
> > > > > > > > > > > > > > > > > > > > listRemoteLogSegments(TopicPartition
> > > > > > > > topicPartition,
> > > > > > > > > > long
> > > > > > > > > > > > > > > > leaderEpoch).
> > > > > > > > > > > > > > > > > > > > When there is an unclean leader
> > election,
> > > > > it's
> > > > > > > > possible
> > > > > > > > > > > > for the
> > > > > > > > > > > > > > > new
> > > > > > > > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > > > > > to not to include certain epochs in its
> > > epoch
> > > > > > > > cache.
> > > > > > > > > > How
> > > > > > > > > > > > are
> > > > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > > > > segments associated with those epochs
> > > being
> > > > > > > > cleaned?
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > That is a good point. This leader will
> > > also
> > > > > > > > cleanup the
> > > > > > > > > > > > epochs
> > > > > > > > > > > > > > > > earlier to
> > > > > > > > > > > > > > > > > > > > its start leader epoch and delete those
> > > > > segments.
> > > > > > > > It
> > > > > > > > > > gets
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > > earliest
> > > > > > > > > > > > > > > > > > > > epoch for a partition and starts
> > deleting
> > > > > > > segments
> > > > > > > > from
> > > > > > > > > > > > that
> > > > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > > > > epoch.
> > > > > > > > > > > > > > > > > > > > We need one more API in RLMM to get the
> > > > > earliest
> > > > > > > > leader
> > > > > > > > > > > > epoch.
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > 601.5 The KIP discusses the handling of
> > > > > unclean
> > > > > > > > leader
> > > > > > > > > > > > elections
> > > > > > > > > > > > > > > > for user
> > > > > > > > > > > > > > > > > > > > topics. What about unclean leader
> > > elections
> > > > > on
> > > > > > > > > > > > > > > > > > > > __remote_log_segment_metadata?
> > > > > > > > > > > > > > > > > > > > This is the same as other system topics
> > > like
> > > > > > > > > > > > consumer_offsets,
> > > > > > > > > > > > > > > > > > > > __transaction_state topics. As
> > discussed
> > > in
> > > > > the
> > > > > > > > > > meeting,
> > > > > > > > > > > > we will
> > > > > > > > > > > > > > > > add the
> > > > > > > > > > > > > > > > > > > > behavior of
> > __remote_log_segment_metadata
> > > > > topic’s
> > > > > > > > > > unclean
> > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > > > > > truncation.
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > 602. It would be useful to clarify the
> > > > > > > limitations
> > > > > > > > in
> > > > > > > > > > the
> > > > > > > > > > > > initial
> > > > > > > > > > > > > > > > > > > release.
> > > > > > > > > > > > > > > > > > > > The KIP mentions not supporting
> > compacted
> > > > > topics.
> > > > > > > > What
> > > > > > > > > > > > about JBOD
> > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > > changing the configuration of a topic
> > > from
> > > > > delete
> > > > > > > > to
> > > > > > > > > > > > compact
> > > > > > > > > > > > > > > after
> > > > > > > > > > > > > > > > > > > remote.
> > > > > > > > > > > > > > > > > > > > log. storage. enable (
> > > > > > > > > > http://remote.log.storage.enable/
> > > > > > > > > > > > ) is
> > > > > > > > > > > > > > > > enabled?
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > This was updated in the KIP earlier.
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > 603. RLM leader tasks:
> > > > > > > > > > > > > > > > > > > > 603.1"It checks for rolled over
> > > LogSegments
> > > > > > > (which
> > > > > > > > have
> > > > > > > > > > > > the last
> > > > > > > > > > > > > > > > message
> > > > > > > > > > > > > > > > > > > > offset less than last stable offset of
> > > that
> > > > > topic
> > > > > > > > > > > > partition) and
> > > > > > > > > > > > > > > > copies
> > > > > > > > > > > > > > > > > > > > them along with their
> > > offset/time/transaction
> > > > > > > > indexes
> > > > > > > > > > and
> > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > epoch
> > > > > > > > > > > > > > > > > > > > cache to the remote tier." It needs to
> > > copy
> > > > > the
> > > > > > > > > > producer
> > > > > > > > > > > > snapshot
> > > > > > > > > > > > > > > > too.
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > Right. It copies producer snapshots too
> > > as
> > > > > > > > mentioned in
> > > > > > > > > > > > > > > > LogSegmentData.
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > 603.2 "Local logs are not cleaned up
> > till
> > > > > those
> > > > > > > > > > segments
> > > > > > > > > > > > are
> > > > > > > > > > > > > > > copied
> > > > > > > > > > > > > > > > > > > > successfully to remote even though
> > their
> > > > > > > retention
> > > > > > > > > > > > time/size is
> > > > > > > > > > > > > > > > reached"
> > > > > > > > > > > > > > > > > > > > This seems weird. If the tiering stops
> > > > > because
> > > > > > > the
> > > > > > > > > > remote
> > > > > > > > > > > > store
> > > > > > > > > > > > > > > is
> > > > > > > > > > > > > > > > not
> > > > > > > > > > > > > > > > > > > > available, we don't want the local data
> > > to
> > > > > grow
> > > > > > > > > > forever.
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > It was clarified in the discussion that
> > > the
> > > > > > > > comment was
> > > > > > > > > > > > more
> > > > > > > > > > > > > > > about
> > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > > local storage goes beyond the
> > > log.retention.
> > > > > The
> > > > > > > > above
> > > > > > > > > > > > statement
> > > > > > > > > > > > > > > > is about
> > > > > > > > > > > > > > > > > > > > local.log.retention but not for the
> > > complete
> > > > > > > > > > > > log.retention. When
> > > > > > > > > > > > > > > it
> > > > > > > > > > > > > > > > > > > > reaches the log.retention then it will
> > > > > delete the
> > > > > > > > local
> > > > > > > > > > > > logs even
> > > > > > > > > > > > > > > > though
> > > > > > > > > > > > > > > > > > > > those are not copied to remote storage.
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > 604. "RLM maintains a bounded
> > > cache(possibly
> > > > > LRU)
> > > > > > > > of
> > > > > > > > > > the
> > > > > > > > > > > > index
> > > > > > > > > > > > > > > > files of
> > > > > > > > > > > > > > > > > > > > remote log segments to avoid multiple
> > > index
> > > > > > > fetches
> > > > > > > > > > from
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > > > > storage. These indexes can be used in
> > the
> > > > > same
> > > > > > > way
> > > > > > > > as
> > > > > > > > > > local
> > > > > > > > > > > > > > > segment
> > > > > > > > > > > > > > > > > > > > indexes are used." Could you provide
> > more
> > > > > details
> > > > > > > > on
> > > > > > > > > > this?
> > > > > > > > > > > > Are
> > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > indexes
> > > > > > > > > > > > > > > > > > > > cached in memory or on disk? If on
> > disk,
> > > > > where
> > > > > > > are
> > > > > > > > they
> > > > > > > > > > > > stored?
> > > > > > > > > > > > > > > > Are the
> > > > > > > > > > > > > > > > > > > > cached indexes bound by a certain size?
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > These are cached on disk and stored in
> > > > > log.dir
> > > > > > > > with a
> > > > > > > > > > name
> > > > > > > > > > > > > > > > > > > > “__remote_log_index_cache”. They are
> > > bound
> > > > > by the
> > > > > > > > total
> > > > > > > > > > > > size.
> > > > > > > > > > > > > > > This
> > > > > > > > > > > > > > > > will
> > > > > > > > > > > > > > > > > > > be
> > > > > > > > > > > > > > > > > > > > exposed as a user configuration,
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > 605. BuildingRemoteLogAux
> > > > > > > > > > > > > > > > > > > > 605.1 In this section, two options are
> > > > > listed.
> > > > > > > > Which
> > > > > > > > > > one is
> > > > > > > > > > > > > > > chosen?
> > > > > > > > > > > > > > > > > > > > Option-2, updated the KIP.
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > 605.2 In option 2, it says "Build the
> > > local
> > > > > > > leader
> > > > > > > > > > epoch
> > > > > > > > > > > > cache by
> > > > > > > > > > > > > > > > cutting
> > > > > > > > > > > > > > > > > > > > the leader epoch sequence received from
> > > > > remote
> > > > > > > > storage
> > > > > > > > > > to
> > > > > > > > > > > > [LSO,
> > > > > > > > > > > > > > > > ELO].
> > > > > > > > > > > > > > > > > > > (LSO
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > = log start offset)." We need to do the
> > > same
> > > > > > > thing
> > > > > > > > for
> > > > > > > > > > the
> > > > > > > > > > > > > > > producer
> > > > > > > > > > > > > > > > > > > > snapshot. However, it's hard to cut the
> > > > > producer
> > > > > > > > > > snapshot
> > > > > > > > > > > > to an
> > > > > > > > > > > > > > > > earlier
> > > > > > > > > > > > > > > > > > > > offset. Another option is to simply
> > take
> > > the
> > > > > > > > lastOffset
> > > > > > > > > > > > from the
> > > > > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > > > > segment and use that as the starting
> > > fetch
> > > > > offset
> > > > > > > > in
> > > > > > > > > > the
> > > > > > > > > > > > > > > follower.
> > > > > > > > > > > > > > > > This
> > > > > > > > > > > > > > > > > > > > avoids the need for cutting.
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > Right, this was mentioned in the
> > > > > “transactional
> > > > > > > > > > support”
> > > > > > > > > > > > section
> > > > > > > > > > > > > > > > about
> > > > > > > > > > > > > > > > > > > > adding these details.
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > 606. ListOffsets: Since we need a
> > version
> > > > > bump,
> > > > > > > > could
> > > > > > > > > > you
> > > > > > > > > > > > > > > document
> > > > > > > > > > > > > > > > it
> > > > > > > > > > > > > > > > > > > > under a protocol change section?
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > Sure, we will update the KIP.
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > 607. "LogStartOffset of a topic can
> > > point to
> > > > > > > > either of
> > > > > > > > > > > > local
> > > > > > > > > > > > > > > > segment or
> > > > > > > > > > > > > > > > > > > > remote segment but it is initialised
> > and
> > > > > > > > maintained in
> > > > > > > > > > the
> > > > > > > > > > > > Log
> > > > > > > > > > > > > > > > class like
> > > > > > > > > > > > > > > > > > > > now. This is already maintained in
> > `Log`
> > > > > class
> > > > > > > > while
> > > > > > > > > > > > loading the
> > > > > > > > > > > > > > > > logs and
> > > > > > > > > > > > > > > > > > > > it can also be fetched from
> > > > > > > > RemoteLogMetadataManager."
> > > > > > > > > > > > What will
> > > > > > > > > > > > > > > > happen
> > > > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > > > the existing logic (e.g. log recovery)
> > > that
> > > > > > > > currently
> > > > > > > > > > > > depends on
> > > > > > > > > > > > > > > > > > > > logStartOffset but assumes it's local?
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > They use a field called
> > > localLogStartOffset
> > > > > which
> > > > > > > > is
> > > > > > > > > > the
> > > > > > > > > > > > local
> > > > > > > > > > > > > > > log
> > > > > > > > > > > > > > > > start
> > > > > > > > > > > > > > > > > > > > offset..
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > 608. Handle expired remote segment: How
> > > does
> > > > > it
> > > > > > > > pick
> > > > > > > > > > up new
> > > > > > > > > > > > > > > > > > > logStartOffset
> > > > > > > > > > > > > > > > > > > > from deleteRecords?
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > Good point. This was not addressed in
> > the
> > > > > KIP.
> > > > > > > Will
> > > > > > > > > > update
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > KIP
> > > > > > > > > > > > > > > > on how
> > > > > > > > > > > > > > > > > > > > the RLM task handles this scenario.
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > 609. RLMM message format:
> > > > > > > > > > > > > > > > > > > > 609.1 It includes both MaxTimestamp and
> > > > > > > > EventTimestamp.
> > > > > > > > > > > > Where
> > > > > > > > > > > > > > > does
> > > > > > > > > > > > > > > > it get
> > > > > > > > > > > > > > > > > > > > both since the message in the log only
> > > > > contains
> > > > > > > one
> > > > > > > > > > > > timestamp?
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > `EventTimeStamp` is the timestamp at
> > > which
> > > > > that
> > > > > > > > segment
> > > > > > > > > > > > metadata
> > > > > > > > > > > > > > > > event is
> > > > > > > > > > > > > > > > > > > > generated. This is more for audits.
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > 609.2 If we change just the state (e.g.
> > > to
> > > > > > > > > > > > DELETE_STARTED), it
> > > > > > > > > > > > > > > > seems it's
> > > > > > > > > > > > > > > > > > > > wasteful to have to include all other
> > > fields
> > > > > not
> > > > > > > > > > changed.
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > This is a good point. We thought about
> > > > > > > incremental
> > > > > > > > > > > > updates. But
> > > > > > > > > > > > > > > we
> > > > > > > > > > > > > > > > want
> > > > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > > > make sure all the events are in the
> > > expected
> > > > > > > order
> > > > > > > > and
> > > > > > > > > > take
> > > > > > > > > > > > > > > action
> > > > > > > > > > > > > > > > based
> > > > > > > > > > > > > > > > > > > > on the latest event. Will think through
> > > the
> > > > > > > > approaches
> > > > > > > > > > in
> > > > > > > > > > > > detail
> > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > > update here.
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > 609.3 Could you document which process
> > > makes
> > > > > the
> > > > > > > > > > following
> > > > > > > > > > > > > > > > transitions
> > > > > > > > > > > > > > > > > > > > DELETE_MARKED, DELETE_STARTED,
> > > > > DELETE_FINISHED?
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > Okay, will document more details.
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > 610.
> > remote.log.reader.max.pending.tasks:
> > > > > > > "Maximum
> > > > > > > > > > remote
> > > > > > > > > > > > log
> > > > > > > > > > > > > > > > reader
> > > > > > > > > > > > > > > > > > > > thread pool task queue size. If the
> > task
> > > > > queue is
> > > > > > > > full,
> > > > > > > > > > > > broker
> > > > > > > > > > > > > > > > will stop
> > > > > > > > > > > > > > > > > > > > reading remote log segments." What does
> > > the
> > > > > > > broker
> > > > > > > > do
> > > > > > > > > > if
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > queue
> > > > > > > > > > > > > > > > is
> > > > > > > > > > > > > > > > > > > > full?
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > It returns an error for this topic
> > > partition.
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > 611. What do we return if the request
> > > > > > > offset/epoch
> > > > > > > > > > doesn't
> > > > > > > > > > > > exist
> > > > > > > > > > > > > > > > in the
> > > > > > > > > > > > > > > > > > > > following API?
> > > > > > > > > > > > > > > > > > > > RemoteLogSegmentMetadata
> > > > > > > > > > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > > > > > > > > > > > > topicPartition, long offset, int
> > > > > epochForOffset)
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > This returns null. But we prefer to
> > > update
> > > > > the
> > > > > > > > return
> > > > > > > > > > type
> > > > > > > > > > > > as
> > > > > > > > > > > > > > > > Optional
> > > > > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > > return Empty if that does not exist.
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > > > > > Satish.
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > On Tue, Sep 1, 2020 at 9:45 AM Jun Rao
> > <
> > > jun@
> > > > > > > > > > confluent.
> > > > > > > > > > > > io (
> > > > > > > > > > > > > > > > > > > > jun@confluent.io ) > wrote:
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >> Hi, Satish,
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >> Thanks for the updated KIP. Made
> > another
> > > > > pass. A
> > > > > > > > few
> > > > > > > > > > more
> > > > > > > > > > > > > > > comments
> > > > > > > > > > > > > > > > > > > below.
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >> 600. The topic deletion logic needs
> > more
> > > > > > > details.
> > > > > > > > > > > > > > > > > > > >> 600.1 The KIP mentions "The controller
> > > > > considers
> > > > > > > > the
> > > > > > > > > > topic
> > > > > > > > > > > > > > > > partition is
> > > > > > > > > > > > > > > > > > > >> deleted only when it determines that
> > > there
> > > > > are
> > > > > > > no
> > > > > > > > log
> > > > > > > > > > > > segments
> > > > > > > > > > > > > > > > for that
> > > > > > > > > > > > > > > > > > > >> topic partition by using RLMM". How is
> > > this
> > > > > > > done?
> > > > > > > > > > 600.2
> > > > > > > > > > > > "If the
> > > > > > > > > > > > > > > > delete
> > > > > > > > > > > > > > > > > > > >> option is enabled then the leader will
> > > stop
> > > > > RLM
> > > > > > > > task
> > > > > > > > > > and
> > > > > > > > > > > > stop
> > > > > > > > > > > > > > > > processing
> > > > > > > > > > > > > > > > > > > >> and it sets all the remote log segment
> > > > > metadata
> > > > > > > of
> > > > > > > > > > that
> > > > > > > > > > > > > > > partition
> > > > > > > > > > > > > > > > with a
> > > > > > > > > > > > > > > > > > > >> delete marker and publishes them to
> > > RLMM."
> > > > > We
> > > > > > > > > > discussed
> > > > > > > > > > > > this
> > > > > > > > > > > > > > > > earlier.
> > > > > > > > > > > > > > > > > > > When
> > > > > > > > > > > > > > > > > > > >> a topic is being deleted, there may
> > not
> > > be a
> > > > > > > > leader
> > > > > > > > > > for
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > > deleted
> > > > > > > > > > > > > > > > > > > >> partition.
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >> 601. Unclean leader election
> > > > > > > > > > > > > > > > > > > >> 601.1 Scenario 1: new empty follower
> > > > > > > > > > > > > > > > > > > >> After step 1, the follower restores up
> > > to
> > > > > offset
> > > > > > > > 3. So
> > > > > > > > > > > > why does
> > > > > > > > > > > > > > > > it have
> > > > > > > > > > > > > > > > > > > >> LE-2 <
> > > > > > > https://issues.apache.org/jira/browse/LE-2>
> > > > > > > > at
> > > > > > > > > > > > offset 5?
> > > > > > > > > > > > > > > > > > > >> 601.2 senario 5: After Step 3, leader
> > A
> > > has
> > > > > > > > > > inconsistent
> > > > > > > > > > > > data
> > > > > > > > > > > > > > > > between
> > > > > > > > > > > > > > > > > > > its
> > > > > > > > > > > > > > > > > > > >> local and the tiered data. For
> > example.
> > > > > offset 3
> > > > > > > > has
> > > > > > > > > > msg
> > > > > > > > > > > > 3 LE-0
> > > > > > > > > > > > > > > > <https://issues.apache.org/jira/browse/LE-0>
> > > > > locally,
> > > > > > > > > > > > > > > > > > > >> but msg 5 LE-1 <
> > > > > > > > > > > > https://issues.apache.org/jira/browse/LE-1> in
> > > > > > > > > > > > > > > > the remote store. While it's ok for the unclean
> > > > > leader
> > > > > > > > > > > > > > > > > > > >> to lose data, it should still return
> > > > > consistent
> > > > > > > > data,
> > > > > > > > > > > > whether
> > > > > > > > > > > > > > > > it's from
> > > > > > > > > > > > > > > > > > > >> the local or the remote store.
> > > > > > > > > > > > > > > > > > > >> 601.3 The follower picks up log start
> > > offset
> > > > > > > > using the
> > > > > > > > > > > > following
> > > > > > > > > > > > > > > > api.
> > > > > > > > > > > > > > > > > > > >> Suppose that we have 3 remote segments
> > > (LE,
> > > > > > > > > > > > SegmentStartOffset)
> > > > > > > > > > > > > > > > as (2,
> > > > > > > > > > > > > > > > > > > >> 10),
> > > > > > > > > > > > > > > > > > > >> (3, 20) and (7, 15) due to an unclean
> > > leader
> > > > > > > > election.
> > > > > > > > > > > > Using the
> > > > > > > > > > > > > > > > > > > following
> > > > > > > > > > > > > > > > > > > >> api will cause logStartOffset to go
> > > backward
> > > > > > > from
> > > > > > > > 20
> > > > > > > > > > to
> > > > > > > > > > > > 15. How
> > > > > > > > > > > > > > > > do we
> > > > > > > > > > > > > > > > > > > >> prevent that?
> > > > > > > > > > > > > > > > > > > >> earliestLogOffset(TopicPartition
> > > > > topicPartition,
> > > > > > > > int
> > > > > > > > > > > > > > > leaderEpoch)
> > > > > > > > > > > > > > > > 601.4
> > > > > > > > > > > > > > > > > > > It
> > > > > > > > > > > > > > > > > > > >> seems that retention is based on
> > > > > > > > > > > > > > > > > > > >> listRemoteLogSegments(TopicPartition
> > > > > > > > topicPartition,
> > > > > > > > > > long
> > > > > > > > > > > > > > > > leaderEpoch).
> > > > > > > > > > > > > > > > > > > >> When there is an unclean leader
> > > election,
> > > > > it's
> > > > > > > > > > possible
> > > > > > > > > > > > for the
> > > > > > > > > > > > > > > > new
> > > > > > > > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > > > > >> to not to include certain epochs in
> > its
> > > > > epoch
> > > > > > > > cache.
> > > > > > > > > > How
> > > > > > > > > > > > are
> > > > > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > > > >> segments associated with those epochs
> > > being
> > > > > > > > cleaned?
> > > > > > > > > > > > 601.5 The
> > > > > > > > > > > > > > > KIP
> > > > > > > > > > > > > > > > > > > >> discusses the handling of unclean
> > leader
> > > > > > > > elections for
> > > > > > > > > > > > user
> > > > > > > > > > > > > > > > topics. What
> > > > > > > > > > > > > > > > > > > >> about unclean leader elections on
> > > > > > > > > > > > > > > > > > > >> __remote_log_segment_metadata?
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >> 602. It would be useful to clarify the
> > > > > > > > limitations in
> > > > > > > > > > the
> > > > > > > > > > > > > > > initial
> > > > > > > > > > > > > > > > > > > release.
> > > > > > > > > > > > > > > > > > > >> The KIP mentions not supporting
> > > compacted
> > > > > > > topics.
> > > > > > > > What
> > > > > > > > > > > > about
> > > > > > > > > > > > > > > JBOD
> > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > >> changing the configuration of a topic
> > > from
> > > > > > > delete
> > > > > > > > to
> > > > > > > > > > > > compact
> > > > > > > > > > > > > > > after
> > > > > > > > > > > > > > > > > > > remote.
> > > > > > > > > > > > > > > > > > > >> log. storage. enable (
> > > > > > > > > > http://remote.log.storage.enable/
> > > > > > > > > > > > ) is
> > > > > > > > > > > > > > > > enabled?
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >> 603. RLM leader tasks:
> > > > > > > > > > > > > > > > > > > >> 603.1"It checks for rolled over
> > > LogSegments
> > > > > > > (which
> > > > > > > > > > have
> > > > > > > > > > > > the last
> > > > > > > > > > > > > > > > message
> > > > > > > > > > > > > > > > > > > >> offset less than last stable offset of
> > > that
> > > > > > > topic
> > > > > > > > > > > > partition) and
> > > > > > > > > > > > > > > > copies
> > > > > > > > > > > > > > > > > > > >> them along with their
> > > > > offset/time/transaction
> > > > > > > > indexes
> > > > > > > > > > and
> > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > epoch
> > > > > > > > > > > > > > > > > > > >> cache to the remote tier." It needs to
> > > copy
> > > > > the
> > > > > > > > > > producer
> > > > > > > > > > > > > > > snapshot
> > > > > > > > > > > > > > > > too.
> > > > > > > > > > > > > > > > > > > >> 603.2 "Local logs are not cleaned up
> > > till
> > > > > those
> > > > > > > > > > segments
> > > > > > > > > > > > are
> > > > > > > > > > > > > > > > copied
> > > > > > > > > > > > > > > > > > > >> successfully to remote even though
> > their
> > > > > > > retention
> > > > > > > > > > > > time/size is
> > > > > > > > > > > > > > > > reached"
> > > > > > > > > > > > > > > > > > > >> This seems weird. If the tiering stops
> > > > > because
> > > > > > > the
> > > > > > > > > > remote
> > > > > > > > > > > > store
> > > > > > > > > > > > > > > > is not
> > > > > > > > > > > > > > > > > > > >> available, we don't want the local
> > data
> > > to
> > > > > grow
> > > > > > > > > > forever.
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >> 604. "RLM maintains a bounded
> > > cache(possibly
> > > > > > > LRU)
> > > > > > > > of
> > > > > > > > > > the
> > > > > > > > > > > > index
> > > > > > > > > > > > > > > > files of
> > > > > > > > > > > > > > > > > > > >> remote log segments to avoid multiple
> > > index
> > > > > > > > fetches
> > > > > > > > > > from
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > > > >> storage. These indexes can be used in
> > > the
> > > > > same
> > > > > > > > way as
> > > > > > > > > > > > local
> > > > > > > > > > > > > > > > segment
> > > > > > > > > > > > > > > > > > > >> indexes are used." Could you provide
> > > more
> > > > > > > details
> > > > > > > > on
> > > > > > > > > > > > this? Are
> > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > indexes
> > > > > > > > > > > > > > > > > > > >> cached in memory or on disk? If on
> > disk,
> > > > > where
> > > > > > > are
> > > > > > > > > > they
> > > > > > > > > > > > stored?
> > > > > > > > > > > > > > > > Are the
> > > > > > > > > > > > > > > > > > > >> cached indexes bound by a certain
> > size?
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >> 605. BuildingRemoteLogAux
> > > > > > > > > > > > > > > > > > > >> 605.1 In this section, two options are
> > > > > listed.
> > > > > > > > Which
> > > > > > > > > > one
> > > > > > > > > > > > is
> > > > > > > > > > > > > > > > chosen?
> > > > > > > > > > > > > > > > > > > 605.2
> > > > > > > > > > > > > > > > > > > >> In option 2, it says "Build the local
> > > leader
> > > > > > > epoch
> > > > > > > > > > cache
> > > > > > > > > > > > by
> > > > > > > > > > > > > > > > cutting the
> > > > > > > > > > > > > > > > > > > >> leader epoch sequence received from
> > > remote
> > > > > > > > storage to
> > > > > > > > > > > > [LSO,
> > > > > > > > > > > > > > > ELO].
> > > > > > > > > > > > > > > > (LSO
> > > > > > > > > > > > > > > > > > > >> = log start offset)." We need to do
> > the
> > > same
> > > > > > > thing
> > > > > > > > > > for the
> > > > > > > > > > > > > > > > producer
> > > > > > > > > > > > > > > > > > > >> snapshot. However, it's hard to cut
> > the
> > > > > producer
> > > > > > > > > > snapshot
> > > > > > > > > > > > to an
> > > > > > > > > > > > > > > > earlier
> > > > > > > > > > > > > > > > > > > >> offset. Another option is to simply
> > > take the
> > > > > > > > > > lastOffset
> > > > > > > > > > > > from the
> > > > > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > > > >> segment and use that as the starting
> > > fetch
> > > > > > > offset
> > > > > > > > in
> > > > > > > > > > the
> > > > > > > > > > > > > > > > follower. This
> > > > > > > > > > > > > > > > > > > >> avoids the need for cutting.
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >> 606. ListOffsets: Since we need a
> > > version
> > > > > bump,
> > > > > > > > could
> > > > > > > > > > you
> > > > > > > > > > > > > > > > document it
> > > > > > > > > > > > > > > > > > > >> under a protocol change section?
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >> 607. "LogStartOffset of a topic can
> > > point to
> > > > > > > > either of
> > > > > > > > > > > > local
> > > > > > > > > > > > > > > > segment or
> > > > > > > > > > > > > > > > > > > >> remote segment but it is initialised
> > and
> > > > > > > > maintained in
> > > > > > > > > > > > the Log
> > > > > > > > > > > > > > > > class
> > > > > > > > > > > > > > > > > > > like
> > > > > > > > > > > > > > > > > > > >> now. This is already maintained in
> > `Log`
> > > > > class
> > > > > > > > while
> > > > > > > > > > > > loading the
> > > > > > > > > > > > > > > > logs
> > > > > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > >> it can also be fetched from
> > > > > > > > RemoteLogMetadataManager."
> > > > > > > > > > > > What will
> > > > > > > > > > > > > > > > happen
> > > > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > > >> the existing logic (e.g. log recovery)
> > > that
> > > > > > > > currently
> > > > > > > > > > > > depends on
> > > > > > > > > > > > > > > > > > > >> logStartOffset but assumes it's local?
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >> 608. Handle expired remote segment:
> > How
> > > > > does it
> > > > > > > > pick
> > > > > > > > > > up
> > > > > > > > > > > > new
> > > > > > > > > > > > > > > > > > > logStartOffset
> > > > > > > > > > > > > > > > > > > >> from deleteRecords?
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >> 609. RLMM message format:
> > > > > > > > > > > > > > > > > > > >> 609.1 It includes both MaxTimestamp
> > and
> > > > > > > > > > EventTimestamp.
> > > > > > > > > > > > Where
> > > > > > > > > > > > > > > > does it
> > > > > > > > > > > > > > > > > > > get
> > > > > > > > > > > > > > > > > > > >> both since the message in the log only
> > > > > contains
> > > > > > > > one
> > > > > > > > > > > > timestamp?
> > > > > > > > > > > > > > > > 609.2 If
> > > > > > > > > > > > > > > > > > > we
> > > > > > > > > > > > > > > > > > > >> change just the state (e.g. to
> > > > > DELETE_STARTED),
> > > > > > > it
> > > > > > > > > > seems
> > > > > > > > > > > > it's
> > > > > > > > > > > > > > > > wasteful
> > > > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > > >> have to include all other fields not
> > > > > changed.
> > > > > > > > 609.3
> > > > > > > > > > Could
> > > > > > > > > > > > you
> > > > > > > > > > > > > > > > document
> > > > > > > > > > > > > > > > > > > >> which process makes the following
> > > > > transitions
> > > > > > > > > > > > DELETE_MARKED,
> > > > > > > > > > > > > > > > > > > >> DELETE_STARTED, DELETE_FINISHED?
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >> 610.
> > > remote.log.reader.max.pending.tasks:
> > > > > > > "Maximum
> > > > > > > > > > remote
> > > > > > > > > > > > log
> > > > > > > > > > > > > > > > reader
> > > > > > > > > > > > > > > > > > > >> thread pool task queue size. If the
> > task
> > > > > queue
> > > > > > > is
> > > > > > > > > > full,
> > > > > > > > > > > > broker
> > > > > > > > > > > > > > > > will stop
> > > > > > > > > > > > > > > > > > > >> reading remote log segments." What
> > does
> > > the
> > > > > > > > broker do
> > > > > > > > > > if
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > > queue is
> > > > > > > > > > > > > > > > > > > >> full?
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >> 611. What do we return if the request
> > > > > > > offset/epoch
> > > > > > > > > > > > doesn't exist
> > > > > > > > > > > > > > > > in the
> > > > > > > > > > > > > > > > > > > >> following API?
> > > > > > > > > > > > > > > > > > > >> RemoteLogSegmentMetadata
> > > > > > > > > > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > > > > > > > > > > > >> topicPartition, long offset, int
> > > > > epochForOffset)
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >> Jun
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >> On Mon, Aug 31, 2020 at 11:19 AM
> > Satish
> > > > > Duggana
> > > > > > > <
> > > > > > > > > > satish.
> > > > > > > > > > > > > > > duggana@
> > > > > > > > > > > > > > > > > > > gmail. com
> > > > > > > > > > > > > > > > > > > >> ( satish.duggana@gmail.com ) > wrote:
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>> KIP is updated with
> > > > > > > > > > > > > > > > > > > >>> - Remote log segment metadata topic
> > > message
> > > > > > > > > > > > format/schema.
> > > > > > > > > > > > > > > > > > > >>> - Added remote log segment metadata
> > > state
> > > > > > > > > > transitions and
> > > > > > > > > > > > > > > > explained how
> > > > > > > > > > > > > > > > > > > >>> the deletion of segments is handled,
> > > > > including
> > > > > > > > the
> > > > > > > > > > case
> > > > > > > > > > > > of
> > > > > > > > > > > > > > > > partition
> > > > > > > > > > > > > > > > > > > >>> deletions.
> > > > > > > > > > > > > > > > > > > >>> - Added a few more limitations in the
> > > "Non
> > > > > > > goals"
> > > > > > > > > > > > section.
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>> Thanks,
> > > > > > > > > > > > > > > > > > > >>> Satish.
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>> On Thu, Aug 27, 2020 at 12:42 AM
> > > Harsha Ch
> > > > > <
> > > > > > > > harsha.
> > > > > > > > > > ch@
> > > > > > > > > > > > > > > gmail.
> > > > > > > > > > > > > > > > com (
> > > > > > > > > > > > > > > > > > > >>> harsha.ch@gmail.com ) > wrote:
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > >>>> Updated the KIP with Meeting Notes
> > > section
> > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>> https:/ / cwiki. apache. org/
> > > confluence/
> > > > > > > > display/
> > > > > > > > > > KAFKA/
> > > > > > > > > > > > > > > > > > > KIP-405 <
> > > > > > > > https://issues.apache.org/jira/browse/KIP-405>
> > > > > > > > > > > > > > > >
> > > > > > > > %3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> > > > > > > > > > > > > > > > > > > >>> (
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > >
> > >
> > https://cwiki.apache.org/confluence/display/KAFKA/KIP-405%3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> > > > > > > > > > > > > > > > > > > >>> )
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > >>>> On Tue, Aug 25, 2020 at 1:03 PM Jun
> > > Rao <
> > > > > jun@
> > > > > > > > > > > > confluent. io
> > > > > > > > > > > > > > > (
> > > > > > > > > > > > > > > > > > > >>>> jun@confluent.io ) > wrote:
> > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>> Hi, Harsha,
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>> Thanks for the summary. Could you
> > > add the
> > > > > > > > summary
> > > > > > > > > > and
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > > recording
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>> link to
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>> the last section of
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>> https:/ / cwiki. apache. org/
> > > confluence/
> > > > > > > > display/
> > > > > > > > > > KAFKA/
> > > > > > > > > > > > > > > > > > > Kafka+Improvement+Proposals
> > > > > > > > > > > > > > > > > > > >>> (
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > >
> > >
> > https://cwiki.apache.org/confluence/display/KAFKA/Kafka+Improvement+Proposals
> > > > > > > > > > > > > > > > > > > >>> )
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>> ?
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>> Jun
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>> On Tue, Aug 25, 2020 at 11:12 AM
> > > Harsha
> > > > > > > > > > Chintalapani <
> > > > > > > > > > > > kafka@
> > > > > > > > > > > > > > > > > > > harsha. io (
> > > > > > > > > > > > > > > > > > > >>>>> kafka@harsha.io ) > wrote:
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>> Thanks everyone for attending the
> > > > > meeting
> > > > > > > > today.
> > > > > > > > > > > > > > > > > > > >>>>>> Here is the recording
> > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>> https:/ / drive. google. com/ file/
> > d/
> > > > > > > > > > > > > > > > > > > 14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/
> > > > > view?usp=sharing
> > > > > > > > > > > > > > > > > > > >>> (
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > >
> > >
> > https://drive.google.com/file/d/14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/view?usp=sharing
> > > > > > > > > > > > > > > > > > > >>> )
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>> Notes:
> > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>> 1. KIP is updated with follower
> > > fetch
> > > > > > > > protocol and
> > > > > > > > > > > > ready to
> > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>> reviewed
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>> 2. Satish to capture schema of
> > > internal
> > > > > > > > metadata
> > > > > > > > > > > > topic in
> > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > KIP
> > > > > > > > > > > > > > > > > > > >>>>>> 3. We will update the KIP with
> > > details
> > > > > of
> > > > > > > > > > different
> > > > > > > > > > > > cases
> > > > > > > > > > > > > > > > > > > >>>>>> 4. Test plan will be captured in a
> > > doc
> > > > > and
> > > > > > > > will
> > > > > > > > > > add
> > > > > > > > > > > > to the
> > > > > > > > > > > > > > > KIP
> > > > > > > > > > > > > > > > > > > >>>>>> 5. Add a section "Limitations" to
> > > > > capture
> > > > > > > the
> > > > > > > > > > > > capabilities
> > > > > > > > > > > > > > > > that
> > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>> will
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>> be
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>> introduced with this KIP and what
> > > will
> > > > > not
> > > > > > > be
> > > > > > > > > > covered
> > > > > > > > > > > > in
> > > > > > > > > > > > > > > this
> > > > > > > > > > > > > > > > KIP.
> > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>> Please add to it I missed
> > anything.
> > > Will
> > > > > > > > produce a
> > > > > > > > > > > > formal
> > > > > > > > > > > > > > > > meeting
> > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>> notes
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>> from next meeting onwards.
> > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>> Thanks,
> > > > > > > > > > > > > > > > > > > >>>>>> Harsha
> > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>> On Mon, Aug 24, 2020 at 9:42 PM,
> > > Ying
> > > > > Zheng
> > > > > > > <
> > > > > > > > > > yingz@
> > > > > > > > > > > > uber.
> > > > > > > > > > > > > > > > com.
> > > > > > > > > > > > > > > > > > > invalid (
> > > > > > > > > > > > > > > > > > > >>>>>> yingz@uber.com.invalid ) > wrote:
> > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>> We did some basic feature tests
> > at
> > > > > Uber.
> > > > > > > The
> > > > > > > > test
> > > > > > > > > > > > cases and
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> > > > > > > > > > > > > > > > > > > >>>>>>> https:/ / docs. google. com/
> > > > > spreadsheets/
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> > > > > already
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> > > > > > > > > > > > > > > > > > > >>>>>>> On Mon, Aug 24, 2020 at 11:10 AM
> > > > > Harsha Ch
> > > > > > > <
> > > > > > > > > > harsha.
> > > > > > > > > > > > ch@
> > > > > > > > > > > > > > > > gmail.
> > > > > > > > > > > > > > > > > > > com (
> > > > > > > > > > > > > > > > > > > >>>>>>> harsha.ch@gmail.com ) >
> > > > > > > > > > > > > > > > > > > >>>>>>>
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> > > > > > > > > > > > > > > > > > > >>>>>>> "Understand commitments towards
> > > driving
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> > > > > > > > > > > > > > > > implementation of
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> > > > > > > > > > > > > > > > > > > >>>>>>> further and how it aligns with
> > > > > participant
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> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>> efforts (ex: in the context of
> > > Uber’s
> > > > > Q3/Q4
> > > > > > > > > > > > roadmap)." What
> > > > > > > > > > > > > > > > is that
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> > > > > > > > > > > > > > > > > > > >>>>>>> On Mon, Aug 24, 2020 at 11:05 AM
> > > > > Kowshik
> > > > > > > > > > Prakasam <
> > > > > > > > > > > > > > > > > > > >>>>>>>
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> > > > > > > > > > > > > > > > > > > >>>>>> kprakasam@ confluent. io (
> > > > > > > > kprakasam@confluent.io
> > > > > > > > > > ) >
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> > > > > > > > > > > > > > > > > > > >>>>>>>
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> > contains a
> > > > > > > proposal
> > > > > > > > for
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> > > > > > > > > > > > > > > > > > > >>> for
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> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>> KIP-405 <
> > > > > > > > > > > > https://issues.apache.org/jira/browse/KIP-405> <
> > > > > > > > > > > > > > > > https:/ / issues. apache. org/ jira/ browse/
> > > KIP-405
> > > > > > > > > > > > > > > > <https://issues.apache.org/jira/browse/KIP-405
> > >
> > > (
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > https://issues.apache.org/jira/browse/KIP-405 )
> > > > > > > > > > >
> > > > > > > > > > > > sync
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> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>> tomorrow:
> > > > > > > > > > > > > > > > > > > >>>>>>>
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> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>> https:/ / docs. google. com/
> > > document/
> > > > > d/ (
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > https://docs.google.com/document/d/ )
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > 1pqo8X5LU8TpwfC_iqSuVPezhfCfhGkbGN2TqiPA3LBU/edit
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>> .
> > > > > > > > > > > > > > > > > > > >>>>>>> Please could you add it to the
> > > Google
> > > > > > > > calendar
> > > > > > > > > > > > invite?
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>> Thank you.
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
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> > > > > > > > > > > > > > > > > > > >>>>>>> Kowshik
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
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> > > > > > > > > > > > > > > > > > > >>>>>>> On Thu, Aug 20, 2020 at 10:58 AM
> > > > > Harsha Ch
> > > > > > > <
> > > > > > > > > > harsha.
> > > > > > > > > > > > ch@
> > > > > > > > > > > > > > > > gmail.
> > > > > > > > > > > > > > > > > > > com (
> > > > > > > > > > > > > > > > > > > >>>>>>> harsha.ch@gmail.com ) >
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>
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> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>> wrote:
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>>
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> > > > > > > > > > > > > > > > > > > >>>>>>> Hi All,
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>> Scheduled a meeting for Tuesday
> > > 9am -
> > > > > 10am.
> > > > > > > > I can
> > > > > > > > > > > > record
> > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > >>>>>>>
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> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>> community to be able to follow
> > the
> > > > > > > > discussion.
> > > > > > > > > > > > > > > > > > > >>>>>>>
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> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>> Jun, please add the required
> > folks
> > > on
> > > > > > > > confluent
> > > > > > > > > > side.
> > > > > > > > > > > > > > > > > > > >>>>>>>
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> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>> Thanks,
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>> Harsha
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>> On Thu, Aug 20, 2020 at 12:33 AM,
> > > > > Alexandre
> > > > > > > > > > Dupriez <
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
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> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>> alexandre.dupriez@
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>>
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> > > > > > > > > > > > > > > > > > > >>>>>>>
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> > > > > > > > > > > > > > > > > > > >>>>>>> gmail. com ( http://gmail.com/
> > ) >
> > > > > wrote:
> > > > > > > > > > > > > > > > > > > >>>>>>>
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> > > > > > > > > > > > > > > > > > > >>>>>>> Hi Jun,
> > > > > > > > > > > > > > > > > > > >>>>>>>
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> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>> Many thanks for your initiative.
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>> If you like, I am happy to attend
> > > at
> > > > > the
> > > > > > > > time you
> > > > > > > > > > > > > > > suggested.
> > > > > > > > > > > > > > > > > > > >>>>>>>
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> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>> Many thanks,
> > > > > > > > > > > > > > > > > > > >>>>>>> Alexandre
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>> Le mer. 19 août 2020 à 22:00,
> > > Harsha
> > > > > Ch <
> > > > > > > > > > harsha. ch@
> > > > > > > > > > > > > > > > gmail. com (
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>> harsha.
> > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>> ch@ gmail. com ( ch@gmail.com )
> > )
> > > > a
> > > > > > > écrit
> > > > > > > > :
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>> Hi Jun,
> > > > > > > > > > > > > > > > > > > >>>>>>> Thanks. This will help a lot.
> > > Tuesday
> > > > > will
> > > > > > > > work
> > > > > > > > > > for
> > > > > > > > > > > > us.
> > > > > > > > > > > > > > > > > > > >>>>>>> -Harsha
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>> On Wed, Aug 19, 2020 at 1:24 PM
> > Jun
> > > > > Rao <
> > > > > > > > jun@
> > > > > > > > > > > > confluent.
> > > > > > > > > > > > > > > > io (
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>> jun@
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>> confluent. io (
> > > http://confluent.io/
> > > > > ) ) >
> > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>> Hi, Satish, Ying, Harsha,
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>> Do you think it would be useful
> > to
> > > > > have a
> > > > > > > > regular
> > > > > > > > > > > > virtual
> > > > > > > > > > > > > > > > meeting
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>> to
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>> discuss this KIP? The goal of the
> > > > > meeting
> > > > > > > > will be
> > > > > > > > > > > > sharing
> > > > > > > > > > > > > > > > > > > >>>>>>> design/development progress and
> > > > > discussing
> > > > > > > > any
> > > > > > > > > > open
> > > > > > > > > > > > issues
> > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>> accelerate
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>> this KIP. If so, will every
> > Tuesday
> > > > > (from
> > > > > > > > next
> > > > > > > > > > week)
> > > > > > > > > > > > > > > 9am-10am
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>> PT
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>> work for you? I can help set up a
> > > Zoom
> > > > > > > > meeting,
> > > > > > > > > > > > invite
> > > > > > > > > > > > > > > > everyone who
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>> might
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>> be interested, have it recorded
> > and
> > > > > shared,
> > > > > > > > etc.
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>> Thanks,
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>> Jun
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>> On Tue, Aug 18, 2020 at 11:01 AM
> > > Satish
> > > > > > > > Duggana <
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>> satish. duggana@ gmail. com (
> > > satish.
> > > > > > > > duggana@
> > > > > > > > > > > > gmail. com
> > > > > > > > > > > > > > > (
> > > > > > > > > > > > > > > > > > > >>>>>>> satish.duggana@gmail.com ) ) >
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>> wrote:
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>> Hi Kowshik,
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>> Thanks for looking into the KIP
> > and
> > > > > sending
> > > > > > > > your
> > > > > > > > > > > > comments.
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > > >>>>>>> 5001. Under the section "Follower
> > > fetch
> > > > > > > > protocol
> > > > > > > > > > in
> > > > > > > > > > > > > > > detail",
> > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > >>>>>>> next-local-offset is the offset
> > > upto
> > > > > which
> > > > > > > > the
> > > > > > > > > > > > segments are
> > > > > > > > > > > > > > > > copied
> > > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > >
> > >
> >

Re: [DISCUSS] KIP-405: Kafka Tiered Storage

[Manikumar <ma...@gmail.com>]

Hi Satish,

Thanks for the KIP.  some of my comments below.

9201. Can we make it clear by mentioning RLM as an internal component and
RLMM and RSM are pluggable components.
It's also good to update/add the RLM, RLMM components  diagrams with
internal components/tasks.

9202. RLMM metadata topic is a non-compact topic. Can we make clear that
metadata topic retention time should be greater
 than user topics. or How about setting retention set to -1 (unlimited) and
let users to modify it.

9203. RLMM has additional responsibility of handling topic delete requests.
With current design, RLMM implementations need
to implement deletion logic. How about making RemotePartitionRemover as a
separate task, which can be reused..

9204. Can we list all the new error codes added by the KIP?

9205. Can we also support  `remote.log.metadata.producr.*`,
`remote.log.metadata.consumer.*` prefixed configs to
override any default configs ?. also include RLMM cache configs, if any.

9206. In the Upgrade section, we have below statement
"Before enabling tiered storage, you should make sure the producer
snapshots are built for all the segments for that topic
in all followers. You should wait till the log retention occurs for all the
segments so that all the segments have producer snapshots."

 Can you add more details about this constraint?


Thanks,
Manikumar

On Tue, Jan 26, 2021 at 1:12 AM Jun Rao <ju...@confluent.io> wrote:

> Hi, Satish,
>
> Thanks for the reply. A few more comments below.
>
> 6000. When RSM/RLMM is not available, it seems that we need to return a
> retriable error to the affected client requests. So, should we add a new
> error code for requests like fetch and listOffset?
>
> 9111. RemotePartitionRemover:
> 91111.1 Could we make it clear that it's part of the default RLMM
> implementation and a separate implementation is needed if one has a
> customized RLMM?
> 91111.2 "RPRM gets all the remote log segments for the partition using RLMM
> and each of these remote log segments is deleted with the next steps.RLMM
> subscribes to the local remote log metadata partitions and it will have the
> segment metadata of all the user topic partitions associated with that
> remote log metadata partition." It seems that RLMM needs to subscribe to
> the remote log metadata partitions first before those segments can be
> deleted?
> 9111.3 There are still references to "remote log cleaners". They need to be
> replaced with RemotePartitionRemover.
>
> 9114.1 Could we add the requirement on log.message.format before enabling
> tiered storage?
>
> 9116. RemoteLogMetadataFormatter: This is used with the ConsoleConsumer
> tool, right? Then, are those new options for ConsoleConsumer and how are
> they passed in?
>
> Thanks,
>
> Jun
>
>
> On Mon, Jan 25, 2021 at 8:02 AM Satish Duggana <sa...@gmail.com>
> wrote:
>
> > Hi Jun,
> >
> > Thanks for your comments. Please find the inline replies below.
> > Several of these were discussed/clarified in our last discussion.
> >
> > 6000. Since we are returning new error codes, we need to bump up the
> > protocol version for Fetch request. Also, it will be useful to document
> all
> > new error codes and whether they are retriable or not.
> > This previous comment doesn't seem to be addressed.
> >
> > Updated KIP on fetch protocol and error code.
> >
> > 9110. flat_file_format: Could you define the serialized representation
> for
> > each field in the header?
> >
> > Added the serialized representation types in the KIP.
> >
> > 9111. RPM has the following 2 steps.
> > "1. The controller publishes delete_partition_marked event to say that
> the
> > partition is marked for deletion. There can be multiple events published
> > when the controller restarts or failover and this event will be
> > deduplicated by RPM.
> > 2. RPM receives the delete_partition_marked and processes it if it is not
> > yet processed earlier."
> > What triggers RPM to read __remote_log_metadata? Is RPM part of the
> default
> > RLMM implementation or is it meant for any RLMM implementation?
> >
> > RPM(or RPRM) is only for the default RLMM implementation. RPM receives
> > the delete_partition_marked events from RLMM and acts on them. Updated
> > KIP with more details.
> >
> > 9112. remote.log.manager.task.retry.backoff.ms: It would be useful to
> make
> > it clear in the comment that this is for the initial retry backoff.
> >
> > Updated the KIP.
> >
> > 9113. RLMM:
> > 9113.1 updateRemoteLogSegmentMetadata(): This comment needs to be
> updated.
> >
> > Updated javadoc of this method.
> >
> > 9113.2 Should RemoteLogSegmentMetadataUpdate include a leadeEpoch field
> > since all other update events have leaderEpoch?
> >
> > +1 to have that,  updated the KIP.
> >
> > 9113.3 Could we rename RemotePartitionState to RemotePartitionDeleteState
> > to make it clear this is for deletion?
> >
> > Sure, updated the KIP.
> >
> > 9113.4 Could we rename RemoteLogState to RemoteLogSegmentState to make it
> > clear this is for segment?
> >
> > Sure, Updated the KIP.
> >
> > 9114.Upgrade:
> > 9114.1 It seems that we require message format > 0.11 for turning on the
> > remote store feature.
> >
> > 9114.2 It's not clear to me why remote.log.storage.system.enable needs to
> > be set to true before bumping up inter.broker.protocol.version.
> >
> > Agree that based on our discussion, this is not required. Upgrade
> > notes is updated.
> >
> > 9114.3 "If the topic-id is not received in the LeaderAndIsr request then
> > remote log storage will not start. But it will log an error message in
> the
> > log. One way to address this is to do a rolling restart of that broker,
> so
> > that the leader will be moved to another broker and the controller will
> > send LeaderAndIsr with the registered topic-id." Why is this needed? With
> > KIP-516, after upgrading to the latest protocol, topicIds are auto
> created.
> >
> > I thought there may be edge cases of not receiving topic-id but you
> > clarified in the meeting that won’t be the case. I agree that it is
> > not needed.
> >
> > 9115. testing: Could you comment on how we plan to do integration and
> > system tests? Do we plan to include, for example, an in-memory
> > implementation of RSM?
> >
> > For integration tests, we can have file based RSM that we have. For
> > system tests, we can have a single node HDFS cluster in one of the
> > containers and use HDFS RSM implementation.
> >
> > 9116. There is still a todo for the message formatter.
> >
> > Updated the KIP with the format.
> >
> >
> > Satish.
> >
> >
> > On Tue, 12 Jan 2021 at 07:07, Jun Rao <ju...@confluent.io> wrote:
> > >
> > > Hi, Satish,
> > >
> > > Thanks for the reply. A few more followup comments.
> > >
> > > 6000. Since we are returning new error codes, we need to bump up the
> > > protocol version for Fetch request. Also, it will be useful to document
> > all
> > > new error codes and whether they are retriable or not.
> > > This previous comment doesn't seem to be addressed.
> > >
> > > 9110. flat_file_format: Could you define the serialized representation
> > for
> > > each field in the header?
> > >
> > > 9111. RPM has the following 2 steps.
> > > "1. The controller publishes delete_partition_marked event to say that
> > the
> > > partition is marked for deletion. There can be multiple events
> published
> > > when the controller restarts or failover and this event will be
> > > deduplicated by RPM.
> > > 2. RPM receives the delete_partition_marked and processes it if it is
> not
> > > yet processed earlier."
> > > What triggers RPM to read __remote_log_metadata? Is RPM part of the
> > default
> > > RLMM implementation or is it meant for any RLMM implementation?
> > >
> > > 9112. remote.log.manager.task.retry.backoff.ms: It would be useful to
> > make
> > > it clear in the comment that this is for the initial retry backoff.
> > >
> > > 9113. RLMM:
> > > 9113.1 updateRemoteLogSegmentMetadata(): This comment needs to be
> > updated.
> > > 9113.2 Should RemoteLogSegmentMetadataUpdate include a leadeEpoch field
> > > since all other update events have leaderEpoch?
> > > 9113.3 Could we rename RemotePartitionState to
> RemotePartitionDeleteState
> > > to make it clear this is for deletion?
> > > 9113.4 Could we rename RemoteLogState to RemoteLogSegmentState to make
> it
> > > clear this is for segment?
> > >
> > > 9114.Upgrade:
> > > 9114.1 It seems that we require message format > 0.11 for turning on
> the
> > > remote store feature.
> > > 9114.2 It's not clear to me why remote.log.storage.system.enable needs
> to
> > > be set to true before bumping up inter.broker.protocol.version.
> > > 9114.3 "If the topic-id is not received in the LeaderAndIsr request
> then
> > > remote log storage will not start. But it will log an error message in
> > the
> > > log. One way to address this is to do a rolling restart of that broker,
> > so
> > > that the leader will be moved to another broker and the controller will
> > > send LeaderAndIsr with the registered topic-id." Why is this needed?
> With
> > > KIP-516, after upgrading to the latest protocol, topicIds are auto
> > created.
> > >
> > > 9115. testing: Could you comment on how we plan to do integration and
> > > system tests? Do we plan to include, for example, an in-memory
> > > implementation of RSM?
> > >
> > > 9116. There is still a todo for the message formatter.
> > >
> > > Jun
> > >
> > > On Sat, Jan 9, 2021 at 2:04 AM Satish Duggana <
> satish.duggana@gmail.com>
> > > wrote:
> > >
> > > > Hi Jun,
> > > > Thanks for your comments. Please find the inline replies below.
> > > >
> > > > 6022. For packages used for server plugins, the convention is to
> > > > use org.apache.kafka.server. See java-based Authorizer as an example.
> > > >
> > > > Sure, ‘org.apache.kafka.common.log.remote.storage’ renamed to
> > > > ‘org.apache.kafka.server.log.remote.storage’.  Updated in the KIP.
> > > >
> > > > 9100. Do we need DeletePartitionStateRecord in flat_file_format? The
> > flat
> > > > file captures the state of the remote segments. After a partition is
> > > > deleted, it seems that we just need to remove the partitions's remote
> > > > segments from the flat file.
> > > >
> > > > DeletePartitionState might not yet have been processed by RPM and not
> > > > completed. We  will not have  that in flat  file format  once it
> > > > reaches DELETE_PARTITION_FINISHED state.
> > > >
> > > > 9101. Upgrade: It will be useful to allow direct upgrade from an old
> > > > version. It seems that's doable. One can just do the normal upgrade
> > first
> > > > and wait enough time (for producer snapshots to be built), and then
> > enable
> > > > remote storage.
> > > >
> > > > Upgrade notes updates in the KIP.
> > > >
> > > > 9102. RemotePartitionRemover(RPM) process: Is it true that RPM starts
> > > > tracking the remote segments when RLMM.onPartitionLeadershipChanges()
> > is
> > > > called with the broker being the leader for __remote_log_metadata
> > > > partition? If so, could we document it?
> > > >
> > > > The current plan is to have that as part of RLMM and RPM uses that to
> > > > get the remote segments list. I will add this detail in the
> respective
> > > > sections.
> > > >
> > > > Satish.
> > > >
> > > > On Wed, 16 Dec 2020 at 23:55, Jun Rao <ju...@confluent.io> wrote:
> > > > >
> > > > > Hi, Satish,
> > > > >
> > > > > Thanks for the reply. A few more followup comments.
> > > > >
> > > > > 6022. For packages used for server plugins, the convention is to
> > > > > use org.apache.kafka.server. See java-based Authorizer as an
> example.
> > > > >
> > > > > 9100. Do we need DeletePartitionStateRecord in flat_file_format?
> The
> > flat
> > > > > file captures the state of the remote segments. After a partition
> is
> > > > > deleted, it seems that we just need to remove the partitions's
> remote
> > > > > segments from the flat file.
> > > > >
> > > > > 9101. Upgrade: It will be useful to allow direct upgrade from an
> old
> > > > > version. It seems that's doable. One can just do the normal upgrade
> > first
> > > > > and wait enough time (for producer snapshots to be built), and then
> > > > enable
> > > > > remote storage.
> > > > >
> > > > > 9102. RemotePartitionRemover(RPM) process: Is it true that RPM
> starts
> > > > > tracking the remote segments when
> > RLMM.onPartitionLeadershipChanges() is
> > > > > called with the broker being the leader for __remote_log_metadata
> > > > > partition? If so, could we document it?
> > > > >
> > > > > Jun
> > > > >
> > > > > On Tue, Dec 15, 2020 at 8:47 AM Kowshik Prakasam <
> > kprakasam@confluent.io
> > > > >
> > > > > wrote:
> > > > >
> > > > > > Hi Satish,
> > > > > >
> > > > > > Thanks for the updates! A few more comments below.
> > > > > >
> > > > > > 9001. Under the "Upgrade" section, there is a line mentioning:
> > > > "Upgrade the
> > > > > > existing Kafka cluster to 2.7 version and allow this to run for
> > the log
> > > > > > retention of user topics that you want to enable tiered storage.
> > This
> > > > will
> > > > > > allow all the topics to have the producer snapshots generated for
> > each
> > > > log
> > > > > > segment." -- Which associated change in AK were you referring to
> > here?
> > > > Is
> > > > > > it: https://github.com/apache/kafka/pull/7929 ? It seems like I
> > don't
> > > > see
> > > > > > it in the 2.7 release branch yet, here is the link:
> > > > > > https://github.com/apache/kafka/commits/2.7.
> > > > > >
> > > > > > 9002. Under the "Upgrade" section, the configuration mentioned is
> > > > > > 'remote.log.storage.system.enable'. However, under "Public
> > Interfaces"
> > > > > > section the corresponding configuration is
> > > > 'remote.storage.system.enable'.
> > > > > > Could we use the same one in both, maybe
> > > > > > 'remote.log.storage.system.enable'?
> > > > > >
> > > > > > 9003. Under "Per Topic Configuration", the KIP recommends setting
> > > > > > 'remote.log.storage.enable' to true at a per-topic level. It will
> > be
> > > > useful
> > > > > > to add a line that if the user wants to enable it for all topics,
> > then
> > > > they
> > > > > > should be able to set the cluster-wide default to true. Also, it
> > will
> > > > be
> > > > > > useful to mention that the KIP currently does not support setting
> > it to
> > > > > > false (after it is set to true), and add that to the future work
> > > > section.
> > > > > >
> > > > > > 9004. Under "Committed offsets file format", the sample provided
> > shows
> > > > > > partition number and offset. Is the topic name required for
> > identifying
> > > > > > which topic the partitions belong to?
> > > > > >
> > > > > > 9005. Under "Internal flat-file store format of remote log
> > metadata",
> > > > it
> > > > > > seems useful to specify both topic name and topic ID for
> debugging
> > > > > > purposes.
> > > > > >
> > > > > > 9006. Under "Internal flat-file store format of remote log
> > metadata",
> > > > the
> > > > > > description of "metadata-topic-offset" currently says "offset of
> > the
> > > > remote
> > > > > > log metadata topic from which this topic partition's remote log
> > > > metadata is
> > > > > > fetched." Just for the wording, perhaps you meant to refer to the
> > > > offset
> > > > > > upto which the file has been committed? i.e. "offset of the
> remote
> > log
> > > > > > metadata topic upto which this topic partition's remote log
> > metadata
> > > > has
> > > > > > been committed into this file."
> > > > > >
> > > > > > 9007. Under "Internal flat-file store format of remote log
> > metadata",
> > > > the
> > > > > > schema of the payload (i.e. beyond the header) seems to contain
> the
> > > > events
> > > > > > from the metadata topic. It seems useful to instead persist the
> > > > > > representation of the materialized state of the events, so that
> > for the
> > > > > > same segment only the latest state is stored. Besides reducing
> > storage
> > > > > > footprint, this also is likely to relate directly with the
> > in-memory
> > > > > > representation of the RLMM cache (which probably is some kind of
> a
> > Map
> > > > with
> > > > > > key being segment ID and value being the segment state), so
> > recovery
> > > > from
> > > > > > disk will be straightforward.
> > > > > >
> > > > > > 9008. Under "Topic deletion lifecycle", step (1), it will be
> > useful to
> > > > > > mention when in the deletion flow does the controller publish the
> > > > > > delete_partition_marked event to say that the partition is marked
> > for
> > > > > > deletion?
> > > > > >
> > > > > > 9009. There are ~4 TODOs in the KIP. Could you please address
> > these or
> > > > > > remove them?
> > > > > >
> > > > > > 9010. There is a reference to a Google doc on the KIP which was
> > used
> > > > > > earlier for discussions. Please could you remove the reference,
> > since
> > > > the
> > > > > > KIP is the source of the truth?
> > > > > >
> > > > > > 9011. This feedback is from an earlier comment. In the
> > > > RemoteStorageManager
> > > > > > interface, there is an API defined for each file type. For
> example,
> > > > > > fetchOffsetIndex, fetchTimestampIndex etc. To avoid the
> > duplication,
> > > > I'd
> > > > > > suggest we can instead have a FileType enum and a common get API
> > based
> > > > on
> > > > > > the FileType. What do you think?
> > > > > >
> > > > > >
> > > > > > Cheers,
> > > > > > Kowshik
> > > > > >
> > > > > >
> > > > > > On Mon, Dec 14, 2020 at 11:07 AM Satish Duggana <
> > > > satish.duggana@gmail.com>
> > > > > > wrote:
> > > > > >
> > > > > > > Hi Jun,
> > > > > > > Thanks for your comments. Please go through the inline replies.
> > > > > > >
> > > > > > >
> > > > > > > 5102.2: It seems that both positions can just be int. Another
> > option
> > > > is
> > > > > > to
> > > > > > > have two methods. Would it be clearer?
> > > > > > >
> > > > > > >     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> > > > > > > remoteLogSegmentMetadata,  int startPosition)
> > > > > > throwsRemoteStorageException;
> > > > > > >
> > > > > > >     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> > > > > > > remoteLogSegmentMetadata, int startPosition, int endPosition)
> > throws
> > > > > > > RemoteStorageException;
> > > > > > >
> > > > > > > That makes sense to me, updated the KIP.
> > > > > > >
> > > > > > > 6003: Could you also update the javadoc for the return value?
> > > > > > >
> > > > > > > Updated.
> > > > > > >
> > > > > > > 6020: local.log.retention.bytes: Should it default to
> > > > log.retention.bytes
> > > > > > > to be consistent with local.log.retention.ms?
> > > > > > >
> > > > > > > Yes, it can be defaulted to log.retention.bytes.
> > > > > > >
> > > > > > > 6021: Could you define TopicIdPartition?
> > > > > > >
> > > > > > > Added TopicIdPartition in the KIP.
> > > > > > >
> > > > > > > 6022: For all public facing classes, could you specify the
> > package
> > > > name?
> > > > > > >
> > > > > > > Updated.
> > > > > > >
> > > > > > >
> > > > > > > Thanks,
> > > > > > > Satish.
> > > > > > >
> > > > > > > On Tue, Dec 8, 2020 at 12:59 AM Jun Rao <ju...@confluent.io>
> > wrote:
> > > > > > > >
> > > > > > > > Hi, Satish,
> > > > > > > >
> > > > > > > > Thanks for the reply. A few more comments below.
> > > > > > > >
> > > > > > > > 5102.2: It seems that both positions can just be int. Another
> > > > option is
> > > > > > > to
> > > > > > > > have two methods. Would it be clearer?
> > > > > > > >
> > > > > > > >     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> > > > > > > > remoteLogSegmentMetadata,
> > > > > > > >                                     int startPosition) throws
> > > > > > > > RemoteStorageException;
> > > > > > > >
> > > > > > > >     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> > > > > > > > remoteLogSegmentMetadata,
> > > > > > > >                                     int startPosition, int
> > > > endPosition)
> > > > > > > > throws RemoteStorageException;
> > > > > > > >
> > > > > > > > 6003: Could you also update the javadoc for the return value?
> > > > > > > >
> > > > > > > > 6010: What kind of tiering throughput have you seen with 5
> > threads?
> > > > > > > >
> > > > > > > > 6020: local.log.retention.bytes: Should it default to
> > > > > > log.retention.bytes
> > > > > > > > to be consistent with local.log.retention.ms?
> > > > > > > >
> > > > > > > > 6021: Could you define TopicIdPartition?
> > > > > > > >
> > > > > > > > 6022: For all public facing classes, could you specify the
> > package
> > > > > > name?
> > > > > > > >
> > > > > > > > It seems that you already added the topicId support. Two
> other
> > > > > > remaining
> > > > > > > > items are (a) the format of local tier metadata storage and
> (b)
> > > > > > upgrade.
> > > > > > > >
> > > > > > > > Jun
> > > > > > > >
> > > > > > > > On Mon, Dec 7, 2020 at 8:56 AM Satish Duggana <
> > > > > > satish.duggana@gmail.com>
> > > > > > > > wrote:
> > > > > > > >
> > > > > > > > > Hi Jun,
> > > > > > > > > Thanks for your comments. Please find the inline replies
> > below.
> > > > > > > > >
> > > > > > > > > >605.2 It's rare for the follower to need the remote data.
> > So,
> > > > the
> > > > > > > current
> > > > > > > > > approach is fine too. Could you document the process of
> > > > rebuilding
> > > > > > the
> > > > > > > > > producer state since we can't simply trim the producerState
> > to an
> > > > > > > offset in
> > > > > > > > > the middle of a segment.
> > > > > > > > >
> > > > > > > > > Will clarify in the KIP.
> > > > > > > > >
> > > > > > > > > >5102.2 Would it be clearer to make startPosiont long and
> > > > endPosition
> > > > > > > of
> > > > > > > > > Optional<Long>?
> > > > > > > > >
> > > > > > > > > We will have arg checks with respective validation. It is
> > not a
> > > > good
> > > > > > > > > practice to have arguments with optional as mentioned here.
> > > > > > > > > https://rules.sonarsource.com/java/RSPEC-3553
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > >5102.5 LogSegmentData still has leaderEpochIndex as File
> > > > instead of
> > > > > > > > > ByteBuffer.
> > > > > > > > >
> > > > > > > > > Updated.
> > > > > > > > >
> > > > > > > > > >5102.7 Could you define all public methods for
> > LogSegmentData?
> > > > > > > > >
> > > > > > > > > Updated.
> > > > > > > > >
> > > > > > > > > >5103.5 Could you change the reference to
> > > > rlm_process_interval_ms and
> > > > > > > > > rlm_retry_interval_ms to the new config names? Also, the
> > retry
> > > > > > interval
> > > > > > > > > config seems still missing. It would be useful to support
> > > > exponential
> > > > > > > > > backoff with the retry interval config.
> > > > > > > > >
> > > > > > > > > Good point. We wanted the retry with truncated exponential
> > > > backoff,
> > > > > > > > > updated the KIP.
> > > > > > > > >
> > > > > > > > > >5111. "RLM follower fetches the earliest offset for the
> > earliest
> > > > > > > leader
> > > > > > > > > epoch by calling RLMM.earliestLogOffset(TopicPartition
> > > > > > topicPartition,
> > > > > > > int
> > > > > > > > > leaderEpoch) and updates that as the log start offset."
> This
> > > > text is
> > > > > > > still
> > > > > > > > > there. Also, could we remove earliestLogOffset() from RLMM?
> > > > > > > > >
> > > > > > > > > Updated.
> > > > > > > > >
> > > > > > > > > >5115. There are still references to "remote log cleaners".
> > > > > > > > >
> > > > > > > > > Updated.
> > > > > > > > >
> > > > > > > > > >6000. Since we are returning new error codes, we need to
> > bump
> > > > up the
> > > > > > > > > protocol version for Fetch request. Also, it will be useful
> > to
> > > > > > > document all
> > > > > > > > > new error codes and whether they are retriable or not.
> > > > > > > > >
> > > > > > > > > Sure, we will add that in the KIP.
> > > > > > > > >
> > > > > > > > > >6001. public Map<Long, Long> segmentLeaderEpochs():
> > Currently,
> > > > > > > leaderEpoch
> > > > > > > > > is int32 instead of long.
> > > > > > > > >
> > > > > > > > > Updated.
> > > > > > > > >
> > > > > > > > > >6002. Is RemoteLogSegmentMetadata.markedForDeletion()
> needed
> > > > given
> > > > > > > > > RemoteLogSegmentMetadata.state()?
> > > > > > > > >
> > > > > > > > > No, it is fixed.
> > > > > > > > >
> > > > > > > > > >6003. RemoteLogSegmentMetadata
> > > > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > topicPartition, long offset, int epochForOffset): Should
> this
> > > > return
> > > > > > > > > Optional<RemoteLogSegmentMetadata>?
> > > > > > > > >
> > > > > > > > > That makes sense, updated.
> > > > > > > > >
> > > > > > > > > >6005. RemoteLogState: It seems it's better to split it
> > between
> > > > > > > > > DeletePartitionUpdate and RemoteLogSegmentMetadataUpdate
> > since
> > > > the
> > > > > > > states
> > > > > > > > > are never shared between the two use cases.
> > > > > > > > >
> > > > > > > > > Agree with that, updated.
> > > > > > > > >
> > > > > > > > > >6006. RLMM.onPartitionLeadershipChanges(): This may be ok.
> > > > However,
> > > > > > > is it
> > > > > > > > > ture that other than the metadata topic, RLMM just needs to
> > know
> > > > > > > whether
> > > > > > > > > there is a replica assigned to this broker and doesn't need
> > to
> > > > know
> > > > > > > whether
> > > > > > > > > the replica is the leader or the follower?
> > > > > > > > >
> > > > > > > > > That may be true. If the implementation does not need that,
> > it
> > > > can
> > > > > > > > > ignore the information in the callback.
> > > > > > > > >
> > > > > > > > > >6007: "Handle expired remote segments (leader and
> > follower)":
> > > > Why is
> > > > > > > this
> > > > > > > > > needed in both the leader and the follower?
> > > > > > > > >
> > > > > > > > > Updated.
> > > > > > > > >
> > > > > > > > > >6008.       "name": "SegmentSizeInBytes",
> > > > > > > > >                 "type": "int64",
> > > > > > > > > The segment size can just be int32.
> > > > > > > > >
> > > > > > > > > Updated.
> > > > > > > > >
> > > > > > > > > >6009. For the record format in the log, it seems that we
> > need
> > > > to add
> > > > > > > > > record
> > > > > > > > > type and record version before the serialized bytes. We can
> > > > follow
> > > > > > the
> > > > > > > > > convention used in
> > > > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > >
> > > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-631%3A+The+Quorum-based+Kafka+Controller#KIP631:TheQuorumbasedKafkaController-RecordFormats
> > > > > > > > >
> > > > > > > > > Yes, KIP already mentions that these are serialized before
> > the
> > > > > > payload
> > > > > > > > > as below. We will mention explicitly that these two are
> > written
> > > > > > before
> > > > > > > > > the data is written.
> > > > > > > > >
> > > > > > > > > RLMM instance on broker publishes the message to the topic
> > with
> > > > key
> > > > > > as
> > > > > > > > > null and value with the below format.
> > > > > > > > >
> > > > > > > > > type      : unsigned var int, represents the value type.
> This
> > > > value
> > > > > > is
> > > > > > > > > 'apikey' as mentioned in the schema.
> > > > > > > > > version : unsigned var int, the 'version' number of the
> type
> > as
> > > > > > > > > mentioned in the schema.
> > > > > > > > > data      : record payload in kafka protocol message
> format.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > >6010. remote.log.manager.thread.pool.size: The default
> > value is
> > > > 10.
> > > > > > > This
> > > > > > > > > might be too high when enabling the tiered feature for the
> > first
> > > > > > time.
> > > > > > > > > Since there are lots of segments that need to be tiered
> > > > initially, a
> > > > > > > large
> > > > > > > > > number of threads could overwhelm the broker.
> > > > > > > > >
> > > > > > > > > Is the default value 5 reasonable?
> > > > > > > > >
> > > > > > > > > 6011. "The number of milli seconds to keep the local log
> > segment
> > > > > > > before it
> > > > > > > > > gets deleted. If not set, the value in
> > `log.retention.minutes` is
> > > > > > > used. If
> > > > > > > > > set to -1, no time limit is applied." We should use
> > > > log.retention.ms
> > > > > > > > > instead of log.retention.minutes.
> > > > > > > > > Nice typo catch. Updated the KIP.
> > > > > > > > >
> > > > > > > > > Thanks,
> > > > > > > > > Satish.
> > > > > > > > >
> > > > > > > > > On Thu, Dec 3, 2020 at 8:03 AM Jun Rao <ju...@confluent.io>
> > wrote:
> > > > > > > > > >
> > > > > > > > > > Hi, Satish,
> > > > > > > > > >
> > > > > > > > > > Thanks for the updated KIP. A few more comments below.
> > > > > > > > > >
> > > > > > > > > > 605.2 It's rare for the follower to need the remote data.
> > So,
> > > > the
> > > > > > > current
> > > > > > > > > > approach is fine too. Could you document the process of
> > > > rebuilding
> > > > > > > the
> > > > > > > > > > producer state since we can't simply trim the
> > producerState to
> > > > an
> > > > > > > offset
> > > > > > > > > in
> > > > > > > > > > the middle of a segment.
> > > > > > > > > >
> > > > > > > > > > 5102.2 Would it be clearer to make startPosiont long and
> > > > > > endPosition
> > > > > > > of
> > > > > > > > > > Optional<Long>?
> > > > > > > > > >
> > > > > > > > > > 5102.5 LogSegmentData still has leaderEpochIndex as File
> > > > instead of
> > > > > > > > > > ByteBuffer.
> > > > > > > > > >
> > > > > > > > > > 5102.7 Could you define all public methods for
> > LogSegmentData?
> > > > > > > > > >
> > > > > > > > > > 5103.5 Could you change the reference to
> > > > rlm_process_interval_ms
> > > > > > and
> > > > > > > > > > rlm_retry_interval_ms to the new config names? Also, the
> > retry
> > > > > > > interval
> > > > > > > > > > config seems still missing. It would be useful to support
> > > > > > exponential
> > > > > > > > > > backoff with the retry interval config.
> > > > > > > > > >
> > > > > > > > > > 5111. "RLM follower fetches the earliest offset for the
> > > > earliest
> > > > > > > leader
> > > > > > > > > > epoch by calling RLMM.earliestLogOffset(TopicPartition
> > > > > > > topicPartition,
> > > > > > > > > int
> > > > > > > > > > leaderEpoch) and updates that as the log start offset."
> > This
> > > > text
> > > > > > is
> > > > > > > > > still
> > > > > > > > > > there. Also, could we remove earliestLogOffset() from
> RLMM?
> > > > > > > > > >
> > > > > > > > > > 5115. There are still references to "remote log
> cleaners".
> > > > > > > > > >
> > > > > > > > > > 6000. Since we are returning new error codes, we need to
> > bump
> > > > up
> > > > > > the
> > > > > > > > > > protocol version for Fetch request. Also, it will be
> > useful to
> > > > > > > document
> > > > > > > > > all
> > > > > > > > > > new error codes and whether they are retriable or not.
> > > > > > > > > >
> > > > > > > > > > 6001. public Map<Long, Long> segmentLeaderEpochs():
> > Currently,
> > > > > > > > > leaderEpoch
> > > > > > > > > > is int32 instead of long.
> > > > > > > > > >
> > > > > > > > > > 6002. Is RemoteLogSegmentMetadata.markedForDeletion()
> > needed
> > > > given
> > > > > > > > > > RemoteLogSegmentMetadata.state()?
> > > > > > > > > >
> > > > > > > > > > 6003. RemoteLogSegmentMetadata
> > > > > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > > topicPartition, long offset, int epochForOffset): Should
> > this
> > > > > > return
> > > > > > > > > > Optional<RemoteLogSegmentMetadata>?
> > > > > > > > > >
> > > > > > > > > > 6004. DeletePartitionUpdate.epoch(): It would be useful
> to
> > > > pick a
> > > > > > > more
> > > > > > > > > > indicative name so that people understand what epoch this
> > is.
> > > > > > > > > >
> > > > > > > > > > 6005. RemoteLogState: It seems it's better to split it
> > between
> > > > > > > > > > DeletePartitionUpdate and RemoteLogSegmentMetadataUpdate
> > since
> > > > the
> > > > > > > states
> > > > > > > > > > are never shared between the two use cases.
> > > > > > > > > >
> > > > > > > > > > 6006. RLMM.onPartitionLeadershipChanges(): This may be
> ok.
> > > > However,
> > > > > > > is it
> > > > > > > > > > ture that other than the metadata topic, RLMM just needs
> to
> > > > know
> > > > > > > whether
> > > > > > > > > > there is a replica assigned to this broker and doesn't
> > need to
> > > > know
> > > > > > > > > whether
> > > > > > > > > > the replica is the leader or the follower?
> > > > > > > > > >
> > > > > > > > > > 6007: "Handle expired remote segments (leader and
> > follower)":
> > > > Why
> > > > > > is
> > > > > > > this
> > > > > > > > > > needed in both the leader and the follower?
> > > > > > > > > >
> > > > > > > > > > 6008.       "name": "SegmentSizeInBytes",
> > > > > > > > > >                 "type": "int64",
> > > > > > > > > > The segment size can just be int32.
> > > > > > > > > >
> > > > > > > > > > 6009. For the record format in the log, it seems that we
> > need
> > > > to
> > > > > > add
> > > > > > > > > record
> > > > > > > > > > type and record version before the serialized bytes. We
> can
> > > > follow
> > > > > > > the
> > > > > > > > > > convention used in
> > > > > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > >
> > > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-631%3A+The+Quorum-based+Kafka+Controller#KIP631:TheQuorumbasedKafkaController-RecordFormats
> > > > > > > > > > .
> > > > > > > > > >
> > > > > > > > > > 6010. remote.log.manager.thread.pool.size: The default
> > value
> > > > is 10.
> > > > > > > This
> > > > > > > > > > might be too high when enabling the tiered feature for
> the
> > > > first
> > > > > > > time.
> > > > > > > > > > Since there are lots of segments that need to be tiered
> > > > initially,
> > > > > > a
> > > > > > > > > large
> > > > > > > > > > number of threads could overwhelm the broker.
> > > > > > > > > >
> > > > > > > > > > 6011. "The number of milli seconds to keep the local log
> > > > segment
> > > > > > > before
> > > > > > > > > it
> > > > > > > > > > gets deleted. If not set, the value in
> > `log.retention.minutes`
> > > > is
> > > > > > > used.
> > > > > > > > > If
> > > > > > > > > > set to -1, no time limit is applied." We should use
> > > > > > log.retention.ms
> > > > > > > > > > instead of log.retention.minutes.
> > > > > > > > > >
> > > > > > > > > > Jun
> > > > > > > > > >
> > > > > > > > > > On Tue, Dec 1, 2020 at 2:42 AM Satish Duggana <
> > > > > > > satish.duggana@gmail.com>
> > > > > > > > > > wrote:
> > > > > > > > > >
> > > > > > > > > > > Hi,
> > > > > > > > > > > We updated the KIP with the points mentioned in the
> > earlier
> > > > mail
> > > > > > > > > > > except for KIP-516 related changes. You can go through
> > them
> > > > and
> > > > > > > let us
> > > > > > > > > > > know if you have any comments. We will update the KIP
> > with
> > > > the
> > > > > > > > > > > remaining todo items and KIP-516 related changes by end
> > of
> > > > this
> > > > > > > > > > > week(5th Dec).
> > > > > > > > > > >
> > > > > > > > > > > Thanks,
> > > > > > > > > > > Satish.
> > > > > > > > > > >
> > > > > > > > > > > On Tue, Nov 10, 2020 at 8:26 PM Satish Duggana <
> > > > > > > > > satish.duggana@gmail.com>
> > > > > > > > > > > wrote:
> > > > > > > > > > > >
> > > > > > > > > > > > Hi Jun,
> > > > > > > > > > > > Thanks for your comments. Please find the inline
> > replies
> > > > below.
> > > > > > > > > > > >
> > > > > > > > > > > > 605.2 "Build the local leader epoch cache by cutting
> > the
> > > > leader
> > > > > > > epoch
> > > > > > > > > > > > sequence received from remote storage to [LSO,
> ELO]." I
> > > > > > > mentioned an
> > > > > > > > > > > issue
> > > > > > > > > > > > earlier. Suppose the leader's local start offset is
> > 100.
> > > > The
> > > > > > > follower
> > > > > > > > > > > finds
> > > > > > > > > > > > a remote segment covering offset range [80, 120). The
> > > > > > > producerState
> > > > > > > > > with
> > > > > > > > > > > > this remote segment is up to offset 120. To trim the
> > > > > > > producerState to
> > > > > > > > > > > > offset 100 requires more work since one needs to
> > download
> > > > the
> > > > > > > > > previous
> > > > > > > > > > > > producerState up to offset 80 and then replay the
> > messages
> > > > from
> > > > > > > 80 to
> > > > > > > > > > > 100.
> > > > > > > > > > > > It seems that it's simpler in this case for the
> > follower
> > > > just
> > > > > > to
> > > > > > > > > take the
> > > > > > > > > > > > remote segment as it is and start fetching from
> offset
> > 120.
> > > > > > > > > > > >
> > > > > > > > > > > > We chose that approach to avoid any edge cases here.
> It
> > > > may be
> > > > > > > > > > > > possible that the remote log segment that is received
> > may
> > > > not
> > > > > > > have
> > > > > > > > > the
> > > > > > > > > > > > same leader epoch sequence from 100-120 as it
> contains
> > on
> > > > the
> > > > > > > > > > > > leader(this can happen due to unclean leader). It is
> > safe
> > > > to
> > > > > > > start
> > > > > > > > > > > > from what the leader returns here.Another way is to
> > find
> > > > the
> > > > > > > remote
> > > > > > > > > > > > log segment
> > > > > > > > > > > >
> > > > > > > > > > > > 5016. Just to echo what Kowshik was saying. It seems
> > that
> > > > > > > > > > > > RLMM.onPartitionLeadershipChanges() is only called on
> > the
> > > > > > > replicas
> > > > > > > > > for a
> > > > > > > > > > > > partition, not on the replicas for the
> > > > > > > __remote_log_segment_metadata
> > > > > > > > > > > > partition. It's not clear how the leader of
> > > > > > > > > __remote_log_segment_metadata
> > > > > > > > > > > > obtains the metadata for remote segments for
> deletion.
> > > > > > > > > > > >
> > > > > > > > > > > > RLMM will always receive the callback for the remote
> > log
> > > > > > metadata
> > > > > > > > > > > > topic partitions hosted on the local broker and these
> > will
> > > > be
> > > > > > > > > > > > subscribed. I will make this clear in the KIP.
> > > > > > > > > > > >
> > > > > > > > > > > > 5100. KIP-516 has been accepted and is being
> > implemented
> > > > now.
> > > > > > > Could
> > > > > > > > > you
> > > > > > > > > > > > update the KIP based on topicID?
> > > > > > > > > > > >
> > > > > > > > > > > > We mentioned KIP-516 and how it helps. We will update
> > this
> > > > KIP
> > > > > > > with
> > > > > > > > > > > > all the changes it brings with KIP-516.
> > > > > > > > > > > >
> > > > > > > > > > > > 5101. RLMM: It would be useful to clarify how the
> > > > following two
> > > > > > > APIs
> > > > > > > > > are
> > > > > > > > > > > > used. According to the wiki, the former is used for
> > topic
> > > > > > > deletion
> > > > > > > > > and
> > > > > > > > > > > the
> > > > > > > > > > > > latter is used for retention. It seems that retention
> > > > should
> > > > > > use
> > > > > > > the
> > > > > > > > > > > former
> > > > > > > > > > > > since remote segments without a matching epoch in the
> > > > leader
> > > > > > > > > (potentially
> > > > > > > > > > > > due to unclean leader election) also need to be
> garbage
> > > > > > > collected.
> > > > > > > > > The
> > > > > > > > > > > > latter seems to be used for the new leader to
> > determine the
> > > > > > last
> > > > > > > > > tiered
> > > > > > > > > > > > segment.
> > > > > > > > > > > >     default Iterator<RemoteLogSegmentMetadata>
> > > > > > > > > > > > listRemoteLogSegments(TopicPartition topicPartition)
> > > > > > > > > > > >     Iterator<RemoteLogSegmentMetadata>
> > > > > > > > > > > listRemoteLogSegments(TopicPartition
> > > > > > > > > > > > topicPartition, long leaderEpoch);
> > > > > > > > > > > >
> > > > > > > > > > > > Right,.that is what we are currently doing. We will
> > update
> > > > the
> > > > > > > > > > > > javadocs and wiki with that. Earlier, we did not want
> > to
> > > > remove
> > > > > > > the
> > > > > > > > > > > > segments which are not matched with leader epochs
> from
> > the
> > > > > > ladder
> > > > > > > > > > > > partition as they may be used later by a replica
> which
> > can
> > > > > > > become a
> > > > > > > > > > > > leader (unclean leader election) and refer those
> > segments.
> > > > But
> > > > > > > that
> > > > > > > > > > > > may leak these segments in remote storage until the
> > topic
> > > > > > > lifetime.
> > > > > > > > > We
> > > > > > > > > > > > decided to cleanup the segments with the oldest
> incase
> > of
> > > > size
> > > > > > > based
> > > > > > > > > > > > retention also.
> > > > > > > > > > > >
> > > > > > > > > > > > 5102. RSM:
> > > > > > > > > > > > 5102.1 For methods like fetchLogSegmentData(), it
> seems
> > > > that
> > > > > > > they can
> > > > > > > > > > > > use RemoteLogSegmentId instead of
> > RemoteLogSegmentMetadata.
> > > > > > > > > > > >
> > > > > > > > > > > > It will be useful to have metadata for RSM to fetch
> log
> > > > > > segment.
> > > > > > > It
> > > > > > > > > > > > may create location/path using id with other metadata
> > too.
> > > > > > > > > > > >
> > > > > > > > > > > > 5102.2 In fetchLogSegmentData(), should we use long
> > > > instead of
> > > > > > > Long?
> > > > > > > > > > > >
> > > > > > > > > > > > Wanted to keep endPosition as optional to read till
> the
> > > > end of
> > > > > > > the
> > > > > > > > > > > > segment and avoid sentinels.
> > > > > > > > > > > >
> > > > > > > > > > > > 5102.3 Why only some of the methods have default
> > > > implementation
> > > > > > > and
> > > > > > > > > > > others
> > > > > > > > > > > > Don't?
> > > > > > > > > > > >
> > > > > > > > > > > > Actually,  RSM will not have any default
> > implementations.
> > > > > > Those 3
> > > > > > > > > > > > methods were made default earlier for tests etc.
> > Updated
> > > > the
> > > > > > > wiki.
> > > > > > > > > > > >
> > > > > > > > > > > > 5102.4. Could we define
> RemoteLogSegmentMetadataUpdate
> > > > > > > > > > > > and DeletePartitionUpdate?
> > > > > > > > > > > >
> > > > > > > > > > > > Sure, they will be added.
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > 5102.5 LogSegmentData: It seems that it's easier to
> > pass
> > > > > > > > > > > > in leaderEpochIndex as a ByteBuffer or byte array
> than
> > a
> > > > file
> > > > > > > since
> > > > > > > > > it
> > > > > > > > > > > will
> > > > > > > > > > > > be generated in memory.
> > > > > > > > > > > >
> > > > > > > > > > > > Right, this is in plan.
> > > > > > > > > > > >
> > > > > > > > > > > > 5102.6 RemoteLogSegmentMetadata: It seems that it
> needs
> > > > both
> > > > > > > > > baseOffset
> > > > > > > > > > > and
> > > > > > > > > > > > startOffset. For example, deleteRecords() could move
> > the
> > > > > > > startOffset
> > > > > > > > > to
> > > > > > > > > > > the
> > > > > > > > > > > > middle of a segment. If we copy the full segment to
> > remote
> > > > > > > storage,
> > > > > > > > > the
> > > > > > > > > > > > baseOffset and the startOffset will be different.
> > > > > > > > > > > >
> > > > > > > > > > > > Good point. startOffset is baseOffset by default, if
> > not
> > > > set
> > > > > > > > > explicitly.
> > > > > > > > > > > >
> > > > > > > > > > > > 5102.7 Could we define all the public methods for
> > > > > > > > > > > RemoteLogSegmentMetadata
> > > > > > > > > > > > and LogSegmentData?
> > > > > > > > > > > >
> > > > > > > > > > > > Sure, updated the wiki.
> > > > > > > > > > > >
> > > > > > > > > > > > 5102.8 Could we document whether endOffset in
> > > > > > > > > RemoteLogSegmentMetadata is
> > > > > > > > > > > > inclusive/exclusive?
> > > > > > > > > > > >
> > > > > > > > > > > > It is inclusive, will update.
> > > > > > > > > > > >
> > > > > > > > > > > > 5103. configs:
> > > > > > > > > > > > 5103.1 Could we define the default value of
> > non-required
> > > > > > configs
> > > > > > > > > (e.g the
> > > > > > > > > > > > size of new thread pools)?
> > > > > > > > > > > >
> > > > > > > > > > > > Sure, that makes sense.
> > > > > > > > > > > >
> > > > > > > > > > > > 5103.2 It seems that local.log.retention.ms should
> > > > default to
> > > > > > > > > > > retention.ms,
> > > > > > > > > > > > instead of remote.log.retention.minutes. Similarly,
> it
> > > > seems
> > > > > > > > > > > > that local.log.retention.bytes should default to
> > > > segment.bytes.
> > > > > > > > > > > >
> > > > > > > > > > > > Right, we do not have  remote.log.retention as we
> > discussed
> > > > > > > earlier.
> > > > > > > > > > > > Thanks for catching the typo.
> > > > > > > > > > > >
> > > > > > > > > > > > 5103.3 remote.log.manager.thread.pool.size: The
> > description
> > > > > > says
> > > > > > > > > "used in
> > > > > > > > > > > > scheduling tasks to copy segments, fetch remote log
> > > > indexes and
> > > > > > > > > clean up
> > > > > > > > > > > > remote log segments". However, there is a separate
> > > > > > > > > > > > config remote.log.reader.threads for fetching remote
> > data.
> > > > It's
> > > > > > > > > weird to
> > > > > > > > > > > > fetch remote index and log in different thread pools
> > since
> > > > both
> > > > > > > are
> > > > > > > > > used
> > > > > > > > > > > > for serving fetch requests.
> > > > > > > > > > > >
> > > > > > > > > > > > Right, remote.log.manager.thread.pool is mainly used
> > for
> > > > > > > copy/cleanup
> > > > > > > > > > > > activities. Fetch path always goes through
> > > > > > > remote.log.reader.threads.
> > > > > > > > > > > >
> > > > > > > > > > > > 5103.4 remote.log.manager.task.interval.ms: Is that
> > the
> > > > amount
> > > > > > > of
> > > > > > > > > time
> > > > > > > > > > > to
> > > > > > > > > > > > back off when there is no work to do? If so, perhaps
> it
> > > > can be
> > > > > > > > > renamed as
> > > > > > > > > > > > backoff.ms.
> > > > > > > > > > > >
> > > > > > > > > > > > This is the delay interval for each iteration. It may
> > be
> > > > > > renamed
> > > > > > > to
> > > > > > > > > > > > remote.log.manager.task.delay.ms
> > > > > > > > > > > >
> > > > > > > > > > > > 5103.5 Are rlm_process_interval_ms and
> > > > rlm_retry_interval_ms
> > > > > > > > > configs? If
> > > > > > > > > > > > so, they need to be listed in this section.
> > > > > > > > > > > >
> > > > > > > > > > > > remote.log.manager.task.interval.ms is the process
> > > > internal,
> > > > > > > retry
> > > > > > > > > > > > interval is missing in the configs, which will be
> > updated
> > > > in
> > > > > > the
> > > > > > > KIP.
> > > > > > > > > > > >
> > > > > > > > > > > > 5104. "RLM maintains a bounded cache(possibly LRU) of
> > the
> > > > index
> > > > > > > > > files of
> > > > > > > > > > > > remote log segments to avoid multiple index fetches
> > from
> > > > the
> > > > > > > remote
> > > > > > > > > > > > storage." Is the RLM in memory or on disk? If on
> disk,
> > > > where is
> > > > > > > it
> > > > > > > > > > > stored?
> > > > > > > > > > > > Do we need a configuration to bound the size?
> > > > > > > > > > > >
> > > > > > > > > > > > It is stored on disk. They are stored in a directory
> > > > > > > > > > > > `remote-log-index-cache` under log dir. We plan to
> > have a
> > > > > > config
> > > > > > > for
> > > > > > > > > > > > that instead of default. We will have a configuration
> > for
> > > > that.
> > > > > > > > > > > >
> > > > > > > > > > > > 5105. The KIP uses local-log-start-offset and
> Earliest
> > > > Local
> > > > > > > Offset
> > > > > > > > > in
> > > > > > > > > > > > different places. It would be useful to standardize
> the
> > > > > > > terminology.
> > > > > > > > > > > >
> > > > > > > > > > > > Sure.
> > > > > > > > > > > >
> > > > > > > > > > > > 5106. The section on "In BuildingRemoteLogAux state".
> > It
> > > > listed
> > > > > > > two
> > > > > > > > > > > options
> > > > > > > > > > > > without saying which option is chosen.
> > > > > > > > > > > > We already mentioned in the KIP that we chose
> option-2.
> > > > > > > > > > > >
> > > > > > > > > > > > 5107. Follower to leader transition: It has step 2,
> > but not
> > > > > > step
> > > > > > > 1.
> > > > > > > > > > > > Step-1 is there but it is not explicitly highlighted.
> > It is
> > > > > > > previous
> > > > > > > > > > > > table to step-2.
> > > > > > > > > > > >
> > > > > > > > > > > > 5108. If a consumer fetches from the remote data and
> > the
> > > > remote
> > > > > > > > > storage
> > > > > > > > > > > is
> > > > > > > > > > > > not available, what error code is used in the fetch
> > > > response?
> > > > > > > > > > > >
> > > > > > > > > > > > Good point. We have not yet defined the error for
> this
> > > > case. We
> > > > > > > need
> > > > > > > > > > > > to define an error message and send the same in fetch
> > > > response.
> > > > > > > > > > > >
> > > > > > > > > > > > 5109. "ListOffsets: For timestamps >= 0, it returns
> the
> > > > first
> > > > > > > message
> > > > > > > > > > > > offset whose timestamp is >= to the given timestamp
> in
> > the
> > > > > > > request.
> > > > > > > > > That
> > > > > > > > > > > > means it checks in remote log time indexes first,
> after
> > > > which
> > > > > > > local
> > > > > > > > > log
> > > > > > > > > > > > time indexes are checked." Could you document which
> > method
> > > > in
> > > > > > > RLMM is
> > > > > > > > > > > used
> > > > > > > > > > > > for this?
> > > > > > > > > > > >
> > > > > > > > > > > > Okay.
> > > > > > > > > > > >
> > > > > > > > > > > > 5110. Stopreplica: "it sets all the remote log
> segment
> > > > metadata
> > > > > > > of
> > > > > > > > > that
> > > > > > > > > > > > partition with a delete marker and publishes them to
> > RLMM."
> > > > > > This
> > > > > > > > > seems
> > > > > > > > > > > > outdated given the new topic deletion logic.
> > > > > > > > > > > >
> > > > > > > > > > > > Will update with KIP-516 related points.
> > > > > > > > > > > >
> > > > > > > > > > > > 5111. "RLM follower fetches the earliest offset for
> the
> > > > > > earliest
> > > > > > > > > leader
> > > > > > > > > > > > epoch by calling
> RLMM.earliestLogOffset(TopicPartition
> > > > > > > > > topicPartition,
> > > > > > > > > > > int
> > > > > > > > > > > > leaderEpoch) and updates that as the log start
> > offset." Do
> > > > we
> > > > > > > need
> > > > > > > > > that
> > > > > > > > > > > > since replication propagates logStartOffset already?
> > > > > > > > > > > >
> > > > > > > > > > > > Good point. Right, existing replication protocol
> takes
> > > > care of
> > > > > > > > > > > > updating the followers’s log start offset received
> > from the
> > > > > > > leader.
> > > > > > > > > > > >
> > > > > > > > > > > > 5112. Is the default maxWaitMs of 500ms enough for
> > fetching
> > > > > > from
> > > > > > > > > remote
> > > > > > > > > > > > storage?
> > > > > > > > > > > >
> > > > > > > > > > > > Remote reads may fail within the current default wait
> > > > time, but
> > > > > > > > > > > > subsequent fetches would be able to serve as that
> data
> > is
> > > > > > stored
> > > > > > > in
> > > > > > > > > > > > the local cache. This cache is currently implemented
> in
> > > > RSMs.
> > > > > > > But we
> > > > > > > > > > > > plan to pull this into the remote log messaging layer
> > in
> > > > > > future.
> > > > > > > > > > > >
> > > > > > > > > > > > 5113. "Committed offsets can be stored in a local
> file
> > to
> > > > avoid
> > > > > > > > > reading
> > > > > > > > > > > the
> > > > > > > > > > > > messages again when a broker is restarted." Could you
> > > > describe
> > > > > > > the
> > > > > > > > > format
> > > > > > > > > > > > and the location of the file? Also, could the same
> > message
> > > > be
> > > > > > > > > processed
> > > > > > > > > > > by
> > > > > > > > > > > > RLMM again after broker restart? If so, how do we
> > handle
> > > > that?
> > > > > > > > > > > >
> > > > > > > > > > > > Sure, we will update in the KIP.
> > > > > > > > > > > >
> > > > > > > > > > > > 5114. Message format
> > > > > > > > > > > > 5114.1 There are two records named
> > > > > > RemoteLogSegmentMetadataRecord
> > > > > > > > > with
> > > > > > > > > > > > apiKey 0 and 1.
> > > > > > > > > > > >
> > > > > > > > > > > > Nice catch, that was a typo. Fixed in the wiki.
> > > > > > > > > > > >
> > > > > > > > > > > > 5114.2 RemoteLogSegmentMetadataRecord: Could we
> > document
> > > > > > whether
> > > > > > > > > > > endOffset
> > > > > > > > > > > > is inclusive/exclusive?
> > > > > > > > > > > > It is inclusive, will update.
> > > > > > > > > > > >
> > > > > > > > > > > > 5114.3 RemoteLogSegmentMetadataRecord: Could you
> > explain
> > > > > > > LeaderEpoch
> > > > > > > > > a
> > > > > > > > > > > bit
> > > > > > > > > > > > more? Is that the epoch of the leader when it copies
> > the
> > > > > > segment
> > > > > > > to
> > > > > > > > > > > remote
> > > > > > > > > > > > storage? Also, how will this field be used?
> > > > > > > > > > > >
> > > > > > > > > > > > Right, this is the leader epoch of the broker which
> > copied
> > > > this
> > > > > > > > > > > > segment. This is helpful in reason about which broker
> > > > copied
> > > > > > the
> > > > > > > > > > > > segment to remote storage.
> > > > > > > > > > > >
> > > > > > > > > > > > 5114.4 EventTimestamp: Could you explain this a bit
> > more?
> > > > Each
> > > > > > > > > record in
> > > > > > > > > > > > Kafka already has a timestamp field. Could we just
> use
> > > > that?
> > > > > > > > > > > >
> > > > > > > > > > > > This is the  timestamp at which  the respective event
> > > > occurred.
> > > > > > > Added
> > > > > > > > > > > > this  to RemoteLogSegmentMetadata as RLMM can be  any
> > other
> > > > > > > > > > > > implementation. We thought about that but it looked
> > > > cleaner to
> > > > > > > use at
> > > > > > > > > > > > the message structure level instead of getting that
> > from
> > > > the
> > > > > > > consumer
> > > > > > > > > > > > record and using that to build the respective event.
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > 5114.5 SegmentSizeInBytes: Could this just be int32?
> > > > > > > > > > > >
> > > > > > > > > > > > Right, it looks like config allows only int value >=
> > 14.
> > > > > > > > > > > >
> > > > > > > > > > > > 5115. RemoteLogCleaner(RLC): This could be confused
> > with
> > > > the
> > > > > > log
> > > > > > > > > cleaner
> > > > > > > > > > > > for compaction. Perhaps it can be renamed to sth like
> > > > > > > > > > > > RemotePartitionRemover.
> > > > > > > > > > > >
> > > > > > > > > > > > I am fine with RemotePartitionRemover or
> > > > > > > RemoteLogDeletionManager(we
> > > > > > > > > > > > have other manager classes like RLM, RLMM).
> > > > > > > > > > > >
> > > > > > > > > > > > 5116. "RLC receives the delete_partition_marked and
> > > > processes
> > > > > > it
> > > > > > > if
> > > > > > > > > it is
> > > > > > > > > > > > not yet processed earlier." How does it know whether
> > > > > > > > > > > > delete_partition_marked has been processed earlier?
> > > > > > > > > > > >
> > > > > > > > > > > > This is to handle duplicate delete_partition_marked
> > > > events. RLC
> > > > > > > > > > > > internally maintains a state for the delete_partition
> > > > events
> > > > > > and
> > > > > > > if
> > > > > > > > > it
> > > > > > > > > > > > already has an existing event then it ignores if it
> is
> > > > already
> > > > > > > being
> > > > > > > > > > > > processed.
> > > > > > > > > > > >
> > > > > > > > > > > > 5117. Should we add a new MessageFormatter to read
> the
> > tier
> > > > > > > metadata
> > > > > > > > > > > topic?
> > > > > > > > > > > >
> > > > > > > > > > > > Right, this is in plan but did not mention it in the
> > KIP.
> > > > This
> > > > > > > will
> > > > > > > > > be
> > > > > > > > > > > > useful for debugging purposes too.
> > > > > > > > > > > >
> > > > > > > > > > > > 5118. "Maximum remote log reader thread pool task
> queue
> > > > size.
> > > > > > If
> > > > > > > the
> > > > > > > > > task
> > > > > > > > > > > > queue is full, broker will stop reading remote log
> > > > segments."
> > > > > > > What
> > > > > > > > > do we
> > > > > > > > > > > > return to the fetch request in this case?
> > > > > > > > > > > >
> > > > > > > > > > > > We return an error response for that partition.
> > > > > > > > > > > >
> > > > > > > > > > > > 5119. It would be useful to list all things not
> > supported
> > > > in
> > > > > > the
> > > > > > > > > first
> > > > > > > > > > > > version in a Future work or Limitations section. For
> > > > example,
> > > > > > > > > compacted
> > > > > > > > > > > > topic, JBOD, changing remote.log.storage.enable from
> > true
> > > > to
> > > > > > > false,
> > > > > > > > > etc.
> > > > > > > > > > > >
> > > > > > > > > > > > We already have a non-goals section which is filled
> > with
> > > > some
> > > > > > of
> > > > > > > > > these
> > > > > > > > > > > > details. Do we need another limitations section?
> > > > > > > > > > > >
> > > > > > > > > > > > Thanks,
> > > > > > > > > > > > Satish.
> > > > > > > > > > > >
> > > > > > > > > > > > On Wed, Nov 4, 2020 at 11:27 PM Jun Rao <
> > jun@confluent.io>
> > > > > > > wrote:
> > > > > > > > > > > > >
> > > > > > > > > > > > > Hi, Satish,
> > > > > > > > > > > > >
> > > > > > > > > > > > > Thanks for the updated KIP. A few more comments
> > below.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 605.2 "Build the local leader epoch cache by
> cutting
> > the
> > > > > > leader
> > > > > > > > > epoch
> > > > > > > > > > > > > sequence received from remote storage to [LSO,
> > ELO]." I
> > > > > > > mentioned
> > > > > > > > > an
> > > > > > > > > > > issue
> > > > > > > > > > > > > earlier. Suppose the leader's local start offset is
> > 100.
> > > > The
> > > > > > > > > follower
> > > > > > > > > > > finds
> > > > > > > > > > > > > a remote segment covering offset range [80, 120).
> The
> > > > > > > producerState
> > > > > > > > > > > with
> > > > > > > > > > > > > this remote segment is up to offset 120. To trim
> the
> > > > > > > producerState
> > > > > > > > > to
> > > > > > > > > > > > > offset 100 requires more work since one needs to
> > > > download the
> > > > > > > > > previous
> > > > > > > > > > > > > producerState up to offset 80 and then replay the
> > > > messages
> > > > > > > from 80
> > > > > > > > > to
> > > > > > > > > > > 100.
> > > > > > > > > > > > > It seems that it's simpler in this case for the
> > follower
> > > > just
> > > > > > > to
> > > > > > > > > take
> > > > > > > > > > > the
> > > > > > > > > > > > > remote segment as it is and start fetching from
> > offset
> > > > 120.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5016. Just to echo what Kowshik was saying. It
> seems
> > that
> > > > > > > > > > > > > RLMM.onPartitionLeadershipChanges() is only called
> > on the
> > > > > > > replicas
> > > > > > > > > for
> > > > > > > > > > > a
> > > > > > > > > > > > > partition, not on the replicas for the
> > > > > > > > > __remote_log_segment_metadata
> > > > > > > > > > > > > partition. It's not clear how the leader of
> > > > > > > > > > > __remote_log_segment_metadata
> > > > > > > > > > > > > obtains the metadata for remote segments for
> > deletion.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5100. KIP-516 has been accepted and is being
> > implemented
> > > > now.
> > > > > > > > > Could you
> > > > > > > > > > > > > update the KIP based on topicID?
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5101. RLMM: It would be useful to clarify how the
> > > > following
> > > > > > two
> > > > > > > > > APIs
> > > > > > > > > > > are
> > > > > > > > > > > > > used. According to the wiki, the former is used for
> > topic
> > > > > > > deletion
> > > > > > > > > and
> > > > > > > > > > > the
> > > > > > > > > > > > > latter is used for retention. It seems that
> retention
> > > > should
> > > > > > > use
> > > > > > > > > the
> > > > > > > > > > > former
> > > > > > > > > > > > > since remote segments without a matching epoch in
> the
> > > > leader
> > > > > > > > > > > (potentially
> > > > > > > > > > > > > due to unclean leader election) also need to be
> > garbage
> > > > > > > collected.
> > > > > > > > > The
> > > > > > > > > > > > > latter seems to be used for the new leader to
> > determine
> > > > the
> > > > > > > last
> > > > > > > > > tiered
> > > > > > > > > > > > > segment.
> > > > > > > > > > > > >     default Iterator<RemoteLogSegmentMetadata>
> > > > > > > > > > > > > listRemoteLogSegments(TopicPartition
> topicPartition)
> > > > > > > > > > > > >     Iterator<RemoteLogSegmentMetadata>
> > > > > > > > > > > listRemoteLogSegments(TopicPartition
> > > > > > > > > > > > > topicPartition, long leaderEpoch);
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5102. RSM:
> > > > > > > > > > > > > 5102.1 For methods like fetchLogSegmentData(), it
> > seems
> > > > that
> > > > > > > they
> > > > > > > > > can
> > > > > > > > > > > > > use RemoteLogSegmentId instead of
> > > > RemoteLogSegmentMetadata.
> > > > > > > > > > > > > 5102.2 In fetchLogSegmentData(), should we use long
> > > > instead
> > > > > > of
> > > > > > > > > Long?
> > > > > > > > > > > > > 5102.3 Why only some of the methods have default
> > > > > > > implementation and
> > > > > > > > > > > others
> > > > > > > > > > > > > don't?
> > > > > > > > > > > > > 5102.4. Could we define
> > RemoteLogSegmentMetadataUpdate
> > > > > > > > > > > > > and DeletePartitionUpdate?
> > > > > > > > > > > > > 5102.5 LogSegmentData: It seems that it's easier to
> > pass
> > > > > > > > > > > > > in leaderEpochIndex as a ByteBuffer or byte array
> > than a
> > > > file
> > > > > > > > > since it
> > > > > > > > > > > will
> > > > > > > > > > > > > be generated in memory.
> > > > > > > > > > > > > 5102.6 RemoteLogSegmentMetadata: It seems that it
> > needs
> > > > both
> > > > > > > > > > > baseOffset and
> > > > > > > > > > > > > startOffset. For example, deleteRecords() could
> move
> > the
> > > > > > > > > startOffset
> > > > > > > > > > > to the
> > > > > > > > > > > > > middle of a segment. If we copy the full segment to
> > > > remote
> > > > > > > > > storage, the
> > > > > > > > > > > > > baseOffset and the startOffset will be different.
> > > > > > > > > > > > > 5102.7 Could we define all the public methods for
> > > > > > > > > > > RemoteLogSegmentMetadata
> > > > > > > > > > > > > and LogSegmentData?
> > > > > > > > > > > > > 5102.8 Could we document whether endOffset in
> > > > > > > > > RemoteLogSegmentMetadata
> > > > > > > > > > > is
> > > > > > > > > > > > > inclusive/exclusive?
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5103. configs:
> > > > > > > > > > > > > 5103.1 Could we define the default value of
> > non-required
> > > > > > > configs
> > > > > > > > > (e.g
> > > > > > > > > > > the
> > > > > > > > > > > > > size of new thread pools)?
> > > > > > > > > > > > > 5103.2 It seems that local.log.retention.ms should
> > > > default
> > > > > > to
> > > > > > > > > > > retention.ms,
> > > > > > > > > > > > > instead of remote.log.retention.minutes. Similarly,
> > it
> > > > seems
> > > > > > > > > > > > > that local.log.retention.bytes should default to
> > > > > > segment.bytes.
> > > > > > > > > > > > > 5103.3 remote.log.manager.thread.pool.size: The
> > > > description
> > > > > > > says
> > > > > > > > > "used
> > > > > > > > > > > in
> > > > > > > > > > > > > scheduling tasks to copy segments, fetch remote log
> > > > indexes
> > > > > > and
> > > > > > > > > clean
> > > > > > > > > > > up
> > > > > > > > > > > > > remote log segments". However, there is a separate
> > > > > > > > > > > > > config remote.log.reader.threads for fetching
> remote
> > > > data.
> > > > > > It's
> > > > > > > > > weird
> > > > > > > > > > > to
> > > > > > > > > > > > > fetch remote index and log in different thread
> pools
> > > > since
> > > > > > > both are
> > > > > > > > > > > used
> > > > > > > > > > > > > for serving fetch requests.
> > > > > > > > > > > > > 5103.4 remote.log.manager.task.interval.ms: Is
> that
> > the
> > > > > > > amount of
> > > > > > > > > > > time to
> > > > > > > > > > > > > back off when there is no work to do? If so,
> perhaps
> > it
> > > > can
> > > > > > be
> > > > > > > > > renamed
> > > > > > > > > > > as
> > > > > > > > > > > > > backoff.ms.
> > > > > > > > > > > > > 5103.5 Are rlm_process_interval_ms and
> > > > rlm_retry_interval_ms
> > > > > > > > > configs?
> > > > > > > > > > > If
> > > > > > > > > > > > > so, they need to be listed in this section.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5104. "RLM maintains a bounded cache(possibly LRU)
> > of the
> > > > > > index
> > > > > > > > > files
> > > > > > > > > > > of
> > > > > > > > > > > > > remote log segments to avoid multiple index fetches
> > from
> > > > the
> > > > > > > remote
> > > > > > > > > > > > > storage." Is the RLM in memory or on disk? If on
> > disk,
> > > > where
> > > > > > > is it
> > > > > > > > > > > stored?
> > > > > > > > > > > > > Do we need a configuration to bound the size?
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5105. The KIP uses local-log-start-offset and
> > Earliest
> > > > Local
> > > > > > > > > Offset in
> > > > > > > > > > > > > different places. It would be useful to standardize
> > the
> > > > > > > > > terminology.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5106. The section on "In BuildingRemoteLogAux
> > state". It
> > > > > > > listed two
> > > > > > > > > > > options
> > > > > > > > > > > > > without saying which option is chosen.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5107. Follower to leader transition: It has step 2,
> > but
> > > > not
> > > > > > > step 1.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5108. If a consumer fetches from the remote data
> and
> > the
> > > > > > remote
> > > > > > > > > > > storage is
> > > > > > > > > > > > > not available, what error code is used in the fetch
> > > > response?
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5109. "ListOffsets: For timestamps >= 0, it returns
> > the
> > > > first
> > > > > > > > > message
> > > > > > > > > > > > > offset whose timestamp is >= to the given timestamp
> > in
> > > > the
> > > > > > > request.
> > > > > > > > > > > That
> > > > > > > > > > > > > means it checks in remote log time indexes first,
> > after
> > > > which
> > > > > > > > > local log
> > > > > > > > > > > > > time indexes are checked." Could you document which
> > > > method in
> > > > > > > RLMM
> > > > > > > > > is
> > > > > > > > > > > used
> > > > > > > > > > > > > for this?
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5110. Stopreplica: "it sets all the remote log
> > segment
> > > > > > > metadata of
> > > > > > > > > that
> > > > > > > > > > > > > partition with a delete marker and publishes them
> to
> > > > RLMM."
> > > > > > > This
> > > > > > > > > seems
> > > > > > > > > > > > > outdated given the new topic deletion logic.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5111. "RLM follower fetches the earliest offset for
> > the
> > > > > > > earliest
> > > > > > > > > leader
> > > > > > > > > > > > > epoch by calling
> > RLMM.earliestLogOffset(TopicPartition
> > > > > > > > > topicPartition,
> > > > > > > > > > > int
> > > > > > > > > > > > > leaderEpoch) and updates that as the log start
> > offset."
> > > > Do we
> > > > > > > need
> > > > > > > > > that
> > > > > > > > > > > > > since replication propagates logStartOffset
> already?
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5112. Is the default maxWaitMs of 500ms enough for
> > > > fetching
> > > > > > > from
> > > > > > > > > remote
> > > > > > > > > > > > > storage?
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5113. "Committed offsets can be stored in a local
> > file to
> > > > > > avoid
> > > > > > > > > > > reading the
> > > > > > > > > > > > > messages again when a broker is restarted." Could
> you
> > > > > > describe
> > > > > > > the
> > > > > > > > > > > format
> > > > > > > > > > > > > and the location of the file? Also, could the same
> > > > message be
> > > > > > > > > > > processed by
> > > > > > > > > > > > > RLMM again after broker restart? If so, how do we
> > handle
> > > > > > that?
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5114. Message format
> > > > > > > > > > > > > 5114.1 There are two records named
> > > > > > > RemoteLogSegmentMetadataRecord
> > > > > > > > > with
> > > > > > > > > > > > > apiKey 0 and 1.
> > > > > > > > > > > > > 5114.2 RemoteLogSegmentMetadataRecord: Could we
> > document
> > > > > > > whether
> > > > > > > > > > > endOffset
> > > > > > > > > > > > > is inclusive/exclusive?
> > > > > > > > > > > > > 5114.3 RemoteLogSegmentMetadataRecord: Could you
> > explain
> > > > > > > > > LeaderEpoch a
> > > > > > > > > > > bit
> > > > > > > > > > > > > more? Is that the epoch of the leader when it
> copies
> > the
> > > > > > > segment to
> > > > > > > > > > > remote
> > > > > > > > > > > > > storage? Also, how will this field be used?
> > > > > > > > > > > > > 5114.4 EventTimestamp: Could you explain this a bit
> > more?
> > > > > > Each
> > > > > > > > > record
> > > > > > > > > > > in
> > > > > > > > > > > > > Kafka already has a timestamp field. Could we just
> > use
> > > > that?
> > > > > > > > > > > > > 5114.5 SegmentSizeInBytes: Could this just be
> int32?
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5115. RemoteLogCleaner(RLC): This could be confused
> > with
> > > > the
> > > > > > > log
> > > > > > > > > > > cleaner
> > > > > > > > > > > > > for compaction. Perhaps it can be renamed to sth
> like
> > > > > > > > > > > > > RemotePartitionRemover.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5116. "RLC receives the delete_partition_marked and
> > > > processes
> > > > > > > it
> > > > > > > > > if it
> > > > > > > > > > > is
> > > > > > > > > > > > > not yet processed earlier." How does it know
> whether
> > > > > > > > > > > > > delete_partition_marked has been processed earlier?
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5117. Should we add a new MessageFormatter to read
> > the
> > > > tier
> > > > > > > > > metadata
> > > > > > > > > > > topic?
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5118. "Maximum remote log reader thread pool task
> > queue
> > > > size.
> > > > > > > If
> > > > > > > > > the
> > > > > > > > > > > task
> > > > > > > > > > > > > queue is full, broker will stop reading remote log
> > > > segments."
> > > > > > > What
> > > > > > > > > do
> > > > > > > > > > > we
> > > > > > > > > > > > > return to the fetch request in this case?
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5119. It would be useful to list all things not
> > > > supported in
> > > > > > > the
> > > > > > > > > first
> > > > > > > > > > > > > version in a Future work or Limitations section.
> For
> > > > example,
> > > > > > > > > compacted
> > > > > > > > > > > > > topic, JBOD, changing remote.log.storage.enable
> from
> > > > true to
> > > > > > > false,
> > > > > > > > > > > etc.
> > > > > > > > > > > > >
> > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > >
> > > > > > > > > > > > > Jun
> > > > > > > > > > > > >
> > > > > > > > > > > > > On Tue, Oct 27, 2020 at 5:57 PM Kowshik Prakasam <
> > > > > > > > > > > kprakasam@confluent.io>
> > > > > > > > > > > > > wrote:
> > > > > > > > > > > > >
> > > > > > > > > > > > > > Hi Satish,
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Thanks for the updates to the KIP. Here are my
> > first
> > > > batch
> > > > > > of
> > > > > > > > > > > > > > comments/suggestions on the latest version of the
> > KIP.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5012. In the RemoteStorageManager interface,
> there
> > is
> > > > an
> > > > > > API
> > > > > > > > > defined
> > > > > > > > > > > for
> > > > > > > > > > > > > > each file type. For example, fetchOffsetIndex,
> > > > > > > > > fetchTimestampIndex
> > > > > > > > > > > etc. To
> > > > > > > > > > > > > > avoid the duplication, I'd suggest we can instead
> > have
> > > > a
> > > > > > > FileType
> > > > > > > > > > > enum and
> > > > > > > > > > > > > > a common get API based on the FileType.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5013. There are some references to the Google doc
> > in
> > > > the
> > > > > > > KIP. I
> > > > > > > > > > > wasn't sure
> > > > > > > > > > > > > > if the Google doc is expected to be in sync with
> > the
> > > > > > > contents of
> > > > > > > > > the
> > > > > > > > > > > wiki.
> > > > > > > > > > > > > > Going forward, it seems easier if just the KIP is
> > > > > > maintained
> > > > > > > as
> > > > > > > > > the
> > > > > > > > > > > source
> > > > > > > > > > > > > > of truth. In this regard, could you please move
> > all the
> > > > > > > > > references
> > > > > > > > > > > to the
> > > > > > > > > > > > > > Google doc, maybe to a separate References
> section
> > at
> > > > the
> > > > > > > bottom
> > > > > > > > > of
> > > > > > > > > > > the
> > > > > > > > > > > > > > KIP?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5014. There are some TODO sections in the KIP.
> > Would
> > > > these
> > > > > > be
> > > > > > > > > filled
> > > > > > > > > > > up in
> > > > > > > > > > > > > > future iterations?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5015. Under "Topic deletion lifecycle", I'm
> trying
> > to
> > > > > > > understand
> > > > > > > > > why
> > > > > > > > > > > do we
> > > > > > > > > > > > > > need delete_partition_marked as well as the
> > > > > > > > > delete_partition_started
> > > > > > > > > > > > > > messages. I couldn't spot a drawback if supposing
> > we
> > > > > > > simplified
> > > > > > > > > the
> > > > > > > > > > > design
> > > > > > > > > > > > > > such that the controller would only write
> > > > > > > > > delete_partition_started
> > > > > > > > > > > message,
> > > > > > > > > > > > > > and RemoteLogCleaner (RLC) instance picks it up
> for
> > > > > > > processing.
> > > > > > > > > What
> > > > > > > > > > > am I
> > > > > > > > > > > > > > missing?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5016. Under "Topic deletion lifecycle", step (4)
> is
> > > > > > > mentioned as
> > > > > > > > > > > "RLC gets
> > > > > > > > > > > > > > all the remote log segments for the partition and
> > each
> > > > of
> > > > > > > these
> > > > > > > > > > > remote log
> > > > > > > > > > > > > > segments is deleted with the next steps.". Since
> > the
> > > > RLC
> > > > > > > instance
> > > > > > > > > > > runs on
> > > > > > > > > > > > > > each tier topic partition leader, how does the
> RLC
> > > > then get
> > > > > > > the
> > > > > > > > > list
> > > > > > > > > > > of
> > > > > > > > > > > > > > remote log segments to be deleted? It will be
> > useful
> > > > to add
> > > > > > > that
> > > > > > > > > > > detail to
> > > > > > > > > > > > > > the KIP.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5017. Under "Public Interfaces -> Configs", there
> > is a
> > > > line
> > > > > > > > > > > mentioning "We
> > > > > > > > > > > > > > will support flipping remote.log.storage.enable
> in
> > next
> > > > > > > > > versions."
> > > > > > > > > > > It will
> > > > > > > > > > > > > > be useful to mention this in the "Future Work"
> > section
> > > > of
> > > > > > > the KIP
> > > > > > > > > > > too.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5018. The KIP introduces a number of
> configuration
> > > > > > > parameters. It
> > > > > > > > > > > will be
> > > > > > > > > > > > > > useful to mention in the KIP if the user should
> > assume
> > > > > > these
> > > > > > > as
> > > > > > > > > > > static
> > > > > > > > > > > > > > configuration in the server.properties file, or
> > dynamic
> > > > > > > > > > > configuration which
> > > > > > > > > > > > > > can be modified without restarting the broker.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5019.  Maybe this is planned as a future update
> to
> > the
> > > > KIP,
> > > > > > > but I
> > > > > > > > > > > thought
> > > > > > > > > > > > > > I'd mention it here. Could you please add details
> > to
> > > > the
> > > > > > KIP
> > > > > > > on
> > > > > > > > > why
> > > > > > > > > > > RocksDB
> > > > > > > > > > > > > > was chosen as the default cache implementation of
> > > > RLMM, and
> > > > > > > how
> > > > > > > > > it
> > > > > > > > > > > is going
> > > > > > > > > > > > > > to be used? Were alternatives
> compared/considered?
> > For
> > > > > > > example,
> > > > > > > > > it
> > > > > > > > > > > would be
> > > > > > > > > > > > > > useful to explain/evaluate the following: 1)
> > > > debuggability
> > > > > > > of the
> > > > > > > > > > > RocksDB
> > > > > > > > > > > > > > JNI interface, 2) performance, 3) portability
> > across
> > > > > > > platforms
> > > > > > > > > and 4)
> > > > > > > > > > > > > > interface parity of RocksDB’s JNI api with it's
> > > > underlying
> > > > > > > C/C++
> > > > > > > > > api.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5020. Following up on (5019), for the RocksDB
> > cache, it
> > > > > > will
> > > > > > > be
> > > > > > > > > > > useful to
> > > > > > > > > > > > > > explain the relationship/mapping between the
> > following
> > > > in
> > > > > > the
> > > > > > > > > KIP:
> > > > > > > > > > > 1) # of
> > > > > > > > > > > > > > tiered partitions, 2) # of partitions of metadata
> > topic
> > > > > > > > > > > > > > __remote_log_metadata and 3) # of RocksDB
> > instances.
> > > > i.e.
> > > > > > is
> > > > > > > the
> > > > > > > > > > > plan to
> > > > > > > > > > > > > > have a RocksDB instance per tiered partition, or
> > per
> > > > > > metadata
> > > > > > > > > topic
> > > > > > > > > > > > > > partition, or just 1 for per broker?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5021. I was looking at the implementation
> > prototype (PR
> > > > > > link:
> > > > > > > > > > > > > > https://github.com/apache/kafka/pull/7561). It
> > seems
> > > > that
> > > > > > a
> > > > > > > > > boolean
> > > > > > > > > > > > > > attribute is being introduced into the Log layer
> to
> > > > check
> > > > > > if
> > > > > > > > > remote
> > > > > > > > > > > log
> > > > > > > > > > > > > > capability is enabled. While the boolean
> footprint
> > is
> > > > small
> > > > > > > at
> > > > > > > > > the
> > > > > > > > > > > moment,
> > > > > > > > > > > > > > this can easily grow in the future and become
> > harder to
> > > > > > > > > > > > > > test/maintain, considering that the Log layer is
> > > > already
> > > > > > > pretty
> > > > > > > > > > > complex. We
> > > > > > > > > > > > > > should start thinking about how to manage such
> > changes
> > > > to
> > > > > > > the Log
> > > > > > > > > > > layer
> > > > > > > > > > > > > > (for the purpose of improved testability, better
> > > > separation
> > > > > > > of
> > > > > > > > > > > concerns and
> > > > > > > > > > > > > > readability). One proposal I have is to take a
> step
> > > > back
> > > > > > and
> > > > > > > > > define a
> > > > > > > > > > > > > > higher level Log interface. Then, the Broker code
> > can
> > > > be
> > > > > > > changed
> > > > > > > > > to
> > > > > > > > > > > use
> > > > > > > > > > > > > > this interface. It can be changed such that only
> a
> > > > handle
> > > > > > to
> > > > > > > the
> > > > > > > > > > > interface
> > > > > > > > > > > > > > is exposed to other components (such as
> LogCleaner,
> > > > > > > > > ReplicaManager
> > > > > > > > > > > etc.)
> > > > > > > > > > > > > > and not the underlying Log object. This approach
> > keeps
> > > > the
> > > > > > > user
> > > > > > > > > of
> > > > > > > > > > > the Log
> > > > > > > > > > > > > > layer agnostic of the whereabouts of the data.
> > > > Underneath
> > > > > > the
> > > > > > > > > > > interface,
> > > > > > > > > > > > > > the implementing classes can completely separate
> > local
> > > > log
> > > > > > > > > > > capabilities
> > > > > > > > > > > > > > from the remote log. For example, the Log class
> > can be
> > > > > > > > > simplified to
> > > > > > > > > > > only
> > > > > > > > > > > > > > manage logic surrounding local log segments and
> > > > metadata.
> > > > > > > > > > > Additionally, a
> > > > > > > > > > > > > > wrapper class can be provided (implementing the
> > higher
> > > > > > level
> > > > > > > Log
> > > > > > > > > > > interface)
> > > > > > > > > > > > > > which will contain any/all logic surrounding
> tiered
> > > > data.
> > > > > > The
> > > > > > > > > wrapper
> > > > > > > > > > > > > > class will wrap around an instance of the Log
> class
> > > > > > > delegating
> > > > > > > > > the
> > > > > > > > > > > local
> > > > > > > > > > > > > > log logic to it. Finally, a handle to the wrapper
> > > > class can
> > > > > > > be
> > > > > > > > > > > exposed to
> > > > > > > > > > > > > > the other components wherever they need a handle
> > to the
> > > > > > > higher
> > > > > > > > > level
> > > > > > > > > > > Log
> > > > > > > > > > > > > > interface.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Cheers,
> > > > > > > > > > > > > > Kowshik
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > On Mon, Oct 26, 2020 at 9:52 PM Satish Duggana <
> > > > > > > > > > > satish.duggana@gmail.com>
> > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Hi,
> > > > > > > > > > > > > > > KIP is updated with 1) topic deletion lifecycle
> > and
> > > > its
> > > > > > > related
> > > > > > > > > > > items
> > > > > > > > > > > > > > > 2) Protocol changes(mainly related to
> > ListOffsets)
> > > > and
> > > > > > > other
> > > > > > > > > minor
> > > > > > > > > > > > > > > changes.
> > > > > > > > > > > > > > > Please go through them and let us know your
> > comments.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > Satish.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > On Mon, Sep 28, 2020 at 9:10 PM Satish Duggana
> <
> > > > > > > > > > > satish.duggana@gmail.com
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Hi Dhruvil,
> > > > > > > > > > > > > > > > Thanks for looking into the KIP and sending
> > your
> > > > > > > comments.
> > > > > > > > > Sorry
> > > > > > > > > > > for
> > > > > > > > > > > > > > > > the late reply, missed it in the mail thread.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 1. Could you describe how retention would
> work
> > with
> > > > > > this
> > > > > > > KIP
> > > > > > > > > and
> > > > > > > > > > > which
> > > > > > > > > > > > > > > > threads are responsible for driving this
> work?
> > I
> > > > > > believe
> > > > > > > > > there
> > > > > > > > > > > are 3
> > > > > > > > > > > > > > > kinds
> > > > > > > > > > > > > > > > of retention processes we are looking at:
> > > > > > > > > > > > > > > >   (a) Regular retention for data in tiered
> > storage
> > > > as
> > > > > > per
> > > > > > > > > > > configured `
> > > > > > > > > > > > > > > > retention.ms` / `retention.bytes`.
> > > > > > > > > > > > > > > >   (b) Local retention for data in local
> > storage as
> > > > per
> > > > > > > > > > > configured `
> > > > > > > > > > > > > > > > local.log.retention.ms` /
> > > > `local.log.retention.bytes`
> > > > > > > > > > > > > > > >   (c) Possibly regular retention for data in
> > local
> > > > > > > storage,
> > > > > > > > > if
> > > > > > > > > > > the
> > > > > > > > > > > > > > > tiering
> > > > > > > > > > > > > > > > task is lagging or for data that is below the
> > log
> > > > start
> > > > > > > > > offset.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Local log retention is done by the existing
> log
> > > > cleanup
> > > > > > > > > tasks.
> > > > > > > > > > > These
> > > > > > > > > > > > > > > > are not done for segments that are not yet
> > copied
> > > > to
> > > > > > > remote
> > > > > > > > > > > storage.
> > > > > > > > > > > > > > > > Remote log cleanup is done by the leader
> > > > partition’s
> > > > > > > RLMTask.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 2. When does a segment become eligible to be
> > > > tiered? Is
> > > > > > > it as
> > > > > > > > > > > soon as
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > segment is rolled and the end offset is less
> > than
> > > > the
> > > > > > > last
> > > > > > > > > stable
> > > > > > > > > > > > > > offset
> > > > > > > > > > > > > > > as
> > > > > > > > > > > > > > > > mentioned in the KIP? I wonder if we need to
> > > > consider
> > > > > > > other
> > > > > > > > > > > parameters
> > > > > > > > > > > > > > > too,
> > > > > > > > > > > > > > > > like the highwatermark so that we are
> > guaranteed
> > > > that
> > > > > > > what
> > > > > > > > > we are
> > > > > > > > > > > > > > tiering
> > > > > > > > > > > > > > > > has been committed to the log and accepted by
> > the
> > > > ISR.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > AFAIK, last stable offset is always <=
> > > > highwatermark.
> > > > > > > This
> > > > > > > > > will
> > > > > > > > > > > make
> > > > > > > > > > > > > > > > sure we are always tiering the message
> segments
> > > > which
> > > > > > > have
> > > > > > > > > been
> > > > > > > > > > > > > > > > accepted by ISR and transactionally
> completed.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 3. The section on "Follower Fetch Scenarios"
> is
> > > > useful
> > > > > > > but
> > > > > > > > > is a
> > > > > > > > > > > bit
> > > > > > > > > > > > > > > > difficult to parse at the moment. It would be
> > > > useful to
> > > > > > > > > > > summarize the
> > > > > > > > > > > > > > > > changes we need in the ReplicaFetcher.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > It may become difficult for users to
> > read/follow
> > > > if we
> > > > > > > add
> > > > > > > > > code
> > > > > > > > > > > changes
> > > > > > > > > > > > > > > here.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 4. Related to the above, it's a bit unclear
> > how we
> > > > are
> > > > > > > > > planning
> > > > > > > > > > > on
> > > > > > > > > > > > > > > > restoring the producer state for a new
> replica.
> > > > Could
> > > > > > you
> > > > > > > > > expand
> > > > > > > > > > > on
> > > > > > > > > > > > > > that?
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > It is mentioned in the KIP
> > > > BuildingRemoteLogAuxState is
> > > > > > > > > > > introduced to
> > > > > > > > > > > > > > > > build the state like leader epoch sequence
> and
> > > > producer
> > > > > > > > > snapshots
> > > > > > > > > > > > > > > > before it starts fetching the data from the
> > > > leader. We
> > > > > > > will
> > > > > > > > > make
> > > > > > > > > > > it
> > > > > > > > > > > > > > > > clear in the KIP.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 5. Similarly, it would be worth summarizing
> the
> > > > > > behavior
> > > > > > > on
> > > > > > > > > > > unclean
> > > > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > election. There are several scenarios to
> > consider
> > > > here:
> > > > > > > data
> > > > > > > > > > > loss from
> > > > > > > > > > > > > > > > local log, data loss from remote log, data
> loss
> > > > from
> > > > > > > metadata
> > > > > > > > > > > topic,
> > > > > > > > > > > > > > etc.
> > > > > > > > > > > > > > > > It's worth describing these in detail.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > We mentioned the cases about unclean leader
> > > > election in
> > > > > > > the
> > > > > > > > > > > follower
> > > > > > > > > > > > > > > > fetch scenarios.
> > > > > > > > > > > > > > > > If there are errors while fetching data from
> > remote
> > > > > > > store or
> > > > > > > > > > > metadata
> > > > > > > > > > > > > > > > store, it will work the same way as it works
> > with
> > > > local
> > > > > > > log.
> > > > > > > > > It
> > > > > > > > > > > > > > > > returns the error back to the caller. Please
> > let us
> > > > > > know
> > > > > > > if
> > > > > > > > > I am
> > > > > > > > > > > > > > > > missing your point here.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 7. For a READ_COMMITTED FetchRequest, how do
> we
> > > > > > retrieve
> > > > > > > and
> > > > > > > > > > > return the
> > > > > > > > > > > > > > > > aborted transaction metadata?
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > When a fetch for a remote log is accessed, we
> > will
> > > > > > fetch
> > > > > > > > > aborted
> > > > > > > > > > > > > > > > transactions along with the segment if it is
> > not
> > > > found
> > > > > > > in the
> > > > > > > > > > > local
> > > > > > > > > > > > > > > > index cache. This includes the case of
> > transaction
> > > > > > index
> > > > > > > not
> > > > > > > > > > > existing
> > > > > > > > > > > > > > > > in the remote log segment. That means, the
> > cache
> > > > entry
> > > > > > > can be
> > > > > > > > > > > empty or
> > > > > > > > > > > > > > > > have a list of aborted transactions.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 8. The `LogSegmentData` class assumes that we
> > have
> > > > a
> > > > > > log
> > > > > > > > > segment,
> > > > > > > > > > > > > > offset
> > > > > > > > > > > > > > > > index, time index, transaction index,
> producer
> > > > snapshot
> > > > > > > and
> > > > > > > > > > > leader
> > > > > > > > > > > > > > epoch
> > > > > > > > > > > > > > > > index. How do we deal with cases where we do
> > not
> > > > have
> > > > > > > one or
> > > > > > > > > > > more of
> > > > > > > > > > > > > > > these?
> > > > > > > > > > > > > > > > For example, we may not have a transaction
> > index or
> > > > > > > producer
> > > > > > > > > > > snapshot
> > > > > > > > > > > > > > > for a
> > > > > > > > > > > > > > > > particular segment. The former is optional,
> > and the
> > > > > > > latter is
> > > > > > > > > > > only kept
> > > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > up to the 3 latest segments.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > This is a good point,  we discussed this in
> the
> > > > last
> > > > > > > meeting.
> > > > > > > > > > > > > > > > Transaction index is optional and we will
> copy
> > them
> > > > > > only
> > > > > > > if
> > > > > > > > > it
> > > > > > > > > > > exists.
> > > > > > > > > > > > > > > > We want to keep all the producer snapshots at
> > each
> > > > log
> > > > > > > > > segment
> > > > > > > > > > > rolling
> > > > > > > > > > > > > > > > and they can be removed if the log copying is
> > > > > > successful
> > > > > > > and
> > > > > > > > > it
> > > > > > > > > > > still
> > > > > > > > > > > > > > > > maintains the existing latest 3 segments, We
> > only
> > > > > > delete
> > > > > > > the
> > > > > > > > > > > producer
> > > > > > > > > > > > > > > > snapshots which have been copied to remote
> log
> > > > segments
> > > > > > > on
> > > > > > > > > > > leader.
> > > > > > > > > > > > > > > > Follower will keep the log segments beyond
> the
> > > > segments
> > > > > > > which
> > > > > > > > > > > have not
> > > > > > > > > > > > > > > > been copied to remote storage. We will update
> > the
> > > > KIP
> > > > > > > with
> > > > > > > > > these
> > > > > > > > > > > > > > > > details.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > Satish.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > On Thu, Sep 17, 2020 at 1:47 AM Dhruvil Shah
> <
> > > > > > > > > > > dhruvil@confluent.io>
> > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Hi Satish, Harsha,
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Thanks for the KIP. Few questions below:
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 1. Could you describe how retention would
> > work
> > > > with
> > > > > > > this
> > > > > > > > > KIP
> > > > > > > > > > > and
> > > > > > > > > > > > > > which
> > > > > > > > > > > > > > > > > threads are responsible for driving this
> > work? I
> > > > > > > believe
> > > > > > > > > there
> > > > > > > > > > > are 3
> > > > > > > > > > > > > > > kinds
> > > > > > > > > > > > > > > > > of retention processes we are looking at:
> > > > > > > > > > > > > > > > >   (a) Regular retention for data in tiered
> > > > storage as
> > > > > > > per
> > > > > > > > > > > configured
> > > > > > > > > > > > > > `
> > > > > > > > > > > > > > > > > retention.ms` / `retention.bytes`.
> > > > > > > > > > > > > > > > >   (b) Local retention for data in local
> > storage
> > > > as
> > > > > > per
> > > > > > > > > > > configured `
> > > > > > > > > > > > > > > > > local.log.retention.ms` /
> > > > > > `local.log.retention.bytes`
> > > > > > > > > > > > > > > > >   (c) Possibly regular retention for data
> in
> > > > local
> > > > > > > > > storage, if
> > > > > > > > > > > the
> > > > > > > > > > > > > > > tiering
> > > > > > > > > > > > > > > > > task is lagging or for data that is below
> > the log
> > > > > > start
> > > > > > > > > offset.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 2. When does a segment become eligible to
> be
> > > > tiered?
> > > > > > > Is it
> > > > > > > > > as
> > > > > > > > > > > soon as
> > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > segment is rolled and the end offset is
> less
> > > > than the
> > > > > > > last
> > > > > > > > > > > stable
> > > > > > > > > > > > > > > offset as
> > > > > > > > > > > > > > > > > mentioned in the KIP? I wonder if we need
> to
> > > > consider
> > > > > > > other
> > > > > > > > > > > > > > parameters
> > > > > > > > > > > > > > > too,
> > > > > > > > > > > > > > > > > like the highwatermark so that we are
> > guaranteed
> > > > that
> > > > > > > what
> > > > > > > > > we
> > > > > > > > > > > are
> > > > > > > > > > > > > > > tiering
> > > > > > > > > > > > > > > > > has been committed to the log and accepted
> > by the
> > > > > > ISR.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 3. The section on "Follower Fetch
> Scenarios"
> > is
> > > > > > useful
> > > > > > > but
> > > > > > > > > is
> > > > > > > > > > > a bit
> > > > > > > > > > > > > > > > > difficult to parse at the moment. It would
> be
> > > > useful
> > > > > > to
> > > > > > > > > > > summarize the
> > > > > > > > > > > > > > > > > changes we need in the ReplicaFetcher.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 4. Related to the above, it's a bit unclear
> > how
> > > > we
> > > > > > are
> > > > > > > > > > > planning on
> > > > > > > > > > > > > > > > > restoring the producer state for a new
> > replica.
> > > > Could
> > > > > > > you
> > > > > > > > > > > expand on
> > > > > > > > > > > > > > > that?
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 5. Similarly, it would be worth summarizing
> > the
> > > > > > > behavior on
> > > > > > > > > > > unclean
> > > > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > > election. There are several scenarios to
> > consider
> > > > > > here:
> > > > > > > > > data
> > > > > > > > > > > loss
> > > > > > > > > > > > > > from
> > > > > > > > > > > > > > > > > local log, data loss from remote log, data
> > loss
> > > > from
> > > > > > > > > metadata
> > > > > > > > > > > topic,
> > > > > > > > > > > > > > > etc.
> > > > > > > > > > > > > > > > > It's worth describing these in detail.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 6. It would be useful to add details about
> > how we
> > > > > > plan
> > > > > > > on
> > > > > > > > > using
> > > > > > > > > > > > > > > RocksDB in
> > > > > > > > > > > > > > > > > the default implementation of
> > > > > > > `RemoteLogMetadataManager`.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 7. For a READ_COMMITTED FetchRequest, how
> do
> > we
> > > > > > > retrieve
> > > > > > > > > and
> > > > > > > > > > > return
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > aborted transaction metadata?
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 8. The `LogSegmentData` class assumes that
> we
> > > > have a
> > > > > > > log
> > > > > > > > > > > segment,
> > > > > > > > > > > > > > > offset
> > > > > > > > > > > > > > > > > index, time index, transaction index,
> > producer
> > > > > > > snapshot and
> > > > > > > > > > > leader
> > > > > > > > > > > > > > > epoch
> > > > > > > > > > > > > > > > > index. How do we deal with cases where we
> do
> > not
> > > > have
> > > > > > > one
> > > > > > > > > or
> > > > > > > > > > > more of
> > > > > > > > > > > > > > > these?
> > > > > > > > > > > > > > > > > For example, we may not have a transaction
> > index
> > > > or
> > > > > > > > > producer
> > > > > > > > > > > snapshot
> > > > > > > > > > > > > > > for a
> > > > > > > > > > > > > > > > > particular segment. The former is optional,
> > and
> > > > the
> > > > > > > latter
> > > > > > > > > is
> > > > > > > > > > > only
> > > > > > > > > > > > > > > kept for
> > > > > > > > > > > > > > > > > up to the 3 latest segments.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > > Dhruvil
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > On Mon, Sep 7, 2020 at 6:54 PM Harsha Ch <
> > > > > > > > > harsha.ch@gmail.com>
> > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > Hi All,
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > We are all working through the last
> meeting
> > > > > > feedback.
> > > > > > > > > I'll
> > > > > > > > > > > cancel
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > tomorrow 's meeting and we can meanwhile
> > > > continue
> > > > > > our
> > > > > > > > > > > discussion in
> > > > > > > > > > > > > > > mailing
> > > > > > > > > > > > > > > > > > list. We can start the regular meeting
> from
> > > > next
> > > > > > week
> > > > > > > > > > > onwards.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > Harsha
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > On Fri, Sep 04, 2020 at 8:41 AM, Satish
> > > > Duggana <
> > > > > > > > > > > > > > > satish.duggana@gmail.com
> > > > > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Hi Jun,
> > > > > > > > > > > > > > > > > > > Thanks for your thorough review and
> > comments.
> > > > > > > Please
> > > > > > > > > find
> > > > > > > > > > > the
> > > > > > > > > > > > > > > inline
> > > > > > > > > > > > > > > > > > > replies below.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 600. The topic deletion logic needs
> more
> > > > details.
> > > > > > > > > > > > > > > > > > > 600.1 The KIP mentions "The controller
> > > > considers
> > > > > > > the
> > > > > > > > > topic
> > > > > > > > > > > > > > > partition is
> > > > > > > > > > > > > > > > > > > deleted only when it determines that
> > there
> > > > are no
> > > > > > > log
> > > > > > > > > > > segments
> > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > that
> > > > > > > > > > > > > > > > > > > topic partition by using RLMM". How is
> > this
> > > > done?
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > It uses RLMM#listSegments() returns all
> > the
> > > > > > > segments
> > > > > > > > > for
> > > > > > > > > > > the
> > > > > > > > > > > > > > given
> > > > > > > > > > > > > > > topic
> > > > > > > > > > > > > > > > > > > partition.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 600.2 "If the delete option is enabled
> > then
> > > > the
> > > > > > > leader
> > > > > > > > > > > will stop
> > > > > > > > > > > > > > > RLM task
> > > > > > > > > > > > > > > > > > > and stop processing and it sets all the
> > > > remote
> > > > > > log
> > > > > > > > > segment
> > > > > > > > > > > > > > > metadata of
> > > > > > > > > > > > > > > > > > > that partition with a delete marker and
> > > > publishes
> > > > > > > them
> > > > > > > > > to
> > > > > > > > > > > RLMM."
> > > > > > > > > > > > > > We
> > > > > > > > > > > > > > > > > > > discussed this earlier. When a topic is
> > being
> > > > > > > deleted,
> > > > > > > > > > > there may
> > > > > > > > > > > > > > > not be a
> > > > > > > > > > > > > > > > > > > leader for the deleted partition.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > This is a good point. As suggested in
> the
> > > > > > meeting,
> > > > > > > we
> > > > > > > > > will
> > > > > > > > > > > add a
> > > > > > > > > > > > > > > separate
> > > > > > > > > > > > > > > > > > > section for topic/partition deletion
> > > > lifecycle
> > > > > > and
> > > > > > > this
> > > > > > > > > > > scenario
> > > > > > > > > > > > > > > will be
> > > > > > > > > > > > > > > > > > > addressed.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 601. Unclean leader election
> > > > > > > > > > > > > > > > > > > 601.1 Scenario 1: new empty follower
> > > > > > > > > > > > > > > > > > > After step 1, the follower restores up
> to
> > > > offset
> > > > > > > 3. So
> > > > > > > > > why
> > > > > > > > > > > does
> > > > > > > > > > > > > > it
> > > > > > > > > > > > > > > have
> > > > > > > > > > > > > > > > > > > LE-2 <
> > > > https://issues.apache.org/jira/browse/LE-2
> > > > > > >
> > > > > > > at
> > > > > > > > > > > offset 5?
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Nice catch. It was showing the leader
> > epoch
> > > > > > fetched
> > > > > > > > > from
> > > > > > > > > > > the
> > > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > > > storage. It should be shown with the
> > > > truncated
> > > > > > till
> > > > > > > > > offset
> > > > > > > > > > > 3.
> > > > > > > > > > > > > > > Updated the
> > > > > > > > > > > > > > > > > > > KIP.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 601.2 senario 5: After Step 3, leader A
> > has
> > > > > > > > > inconsistent
> > > > > > > > > > > data
> > > > > > > > > > > > > > > between its
> > > > > > > > > > > > > > > > > > > local and the tiered data. For example.
> > > > offset 3
> > > > > > > has
> > > > > > > > > msg 3
> > > > > > > > > > > LE-0
> > > > > > > > > > > > > > > <https://issues.apache.org/jira/browse/LE-0>
> > > > locally,
> > > > > > > > > > > > > > > > > > > but msg 5 LE-1 <
> > > > > > > > > https://issues.apache.org/jira/browse/LE-1>
> > > > > > > > > > > in
> > > > > > > > > > > > > > > the remote store. While it's ok for the unclean
> > > > leader
> > > > > > > > > > > > > > > > > > > to lose data, it should still return
> > > > consistent
> > > > > > > data,
> > > > > > > > > > > whether
> > > > > > > > > > > > > > it's
> > > > > > > > > > > > > > > from
> > > > > > > > > > > > > > > > > > > the local or the remote store.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > There is no inconsistency here as LE-0
> > > > > > > > > > > > > > > <https://issues.apache.org/jira/browse/LE-0>
> > > > offsets are
> > > > > > > [0,
> > > > > > > > > 4]
> > > > > > > > > > > and LE-2
> > > > > > > > > > > > > > > <https://issues.apache.org/jira/browse/LE-2>:
> > > > > > > > > > > > > > > > > > > [5, ]. It will always get the right
> > records
> > > > for
> > > > > > the
> > > > > > > > > given
> > > > > > > > > > > offset
> > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > leader epoch. In case of remote, RSM is
> > > > invoked
> > > > > > to
> > > > > > > get
> > > > > > > > > the
> > > > > > > > > > > remote
> > > > > > > > > > > > > > > log
> > > > > > > > > > > > > > > > > > > segment that contains the given offset
> > with
> > > > the
> > > > > > > leader
> > > > > > > > > > > epoch.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 601.4 It seems that retention is based
> on
> > > > > > > > > > > > > > > > > > > listRemoteLogSegments(TopicPartition
> > > > > > > topicPartition,
> > > > > > > > > long
> > > > > > > > > > > > > > > leaderEpoch).
> > > > > > > > > > > > > > > > > > > When there is an unclean leader
> election,
> > > > it's
> > > > > > > possible
> > > > > > > > > > > for the
> > > > > > > > > > > > > > new
> > > > > > > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > > > > to not to include certain epochs in its
> > epoch
> > > > > > > cache.
> > > > > > > > > How
> > > > > > > > > > > are
> > > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > > > segments associated with those epochs
> > being
> > > > > > > cleaned?
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > That is a good point. This leader will
> > also
> > > > > > > cleanup the
> > > > > > > > > > > epochs
> > > > > > > > > > > > > > > earlier to
> > > > > > > > > > > > > > > > > > > its start leader epoch and delete those
> > > > segments.
> > > > > > > It
> > > > > > > > > gets
> > > > > > > > > > > the
> > > > > > > > > > > > > > > earliest
> > > > > > > > > > > > > > > > > > > epoch for a partition and starts
> deleting
> > > > > > segments
> > > > > > > from
> > > > > > > > > > > that
> > > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > > > epoch.
> > > > > > > > > > > > > > > > > > > We need one more API in RLMM to get the
> > > > earliest
> > > > > > > leader
> > > > > > > > > > > epoch.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 601.5 The KIP discusses the handling of
> > > > unclean
> > > > > > > leader
> > > > > > > > > > > elections
> > > > > > > > > > > > > > > for user
> > > > > > > > > > > > > > > > > > > topics. What about unclean leader
> > elections
> > > > on
> > > > > > > > > > > > > > > > > > > __remote_log_segment_metadata?
> > > > > > > > > > > > > > > > > > > This is the same as other system topics
> > like
> > > > > > > > > > > consumer_offsets,
> > > > > > > > > > > > > > > > > > > __transaction_state topics. As
> discussed
> > in
> > > > the
> > > > > > > > > meeting,
> > > > > > > > > > > we will
> > > > > > > > > > > > > > > add the
> > > > > > > > > > > > > > > > > > > behavior of
> __remote_log_segment_metadata
> > > > topic’s
> > > > > > > > > unclean
> > > > > > > > > > > leader
> > > > > > > > > > > > > > > > > > > truncation.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 602. It would be useful to clarify the
> > > > > > limitations
> > > > > > > in
> > > > > > > > > the
> > > > > > > > > > > initial
> > > > > > > > > > > > > > > > > > release.
> > > > > > > > > > > > > > > > > > > The KIP mentions not supporting
> compacted
> > > > topics.
> > > > > > > What
> > > > > > > > > > > about JBOD
> > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > changing the configuration of a topic
> > from
> > > > delete
> > > > > > > to
> > > > > > > > > > > compact
> > > > > > > > > > > > > > after
> > > > > > > > > > > > > > > > > > remote.
> > > > > > > > > > > > > > > > > > > log. storage. enable (
> > > > > > > > > http://remote.log.storage.enable/
> > > > > > > > > > > ) is
> > > > > > > > > > > > > > > enabled?
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > This was updated in the KIP earlier.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 603. RLM leader tasks:
> > > > > > > > > > > > > > > > > > > 603.1"It checks for rolled over
> > LogSegments
> > > > > > (which
> > > > > > > have
> > > > > > > > > > > the last
> > > > > > > > > > > > > > > message
> > > > > > > > > > > > > > > > > > > offset less than last stable offset of
> > that
> > > > topic
> > > > > > > > > > > partition) and
> > > > > > > > > > > > > > > copies
> > > > > > > > > > > > > > > > > > > them along with their
> > offset/time/transaction
> > > > > > > indexes
> > > > > > > > > and
> > > > > > > > > > > leader
> > > > > > > > > > > > > > > epoch
> > > > > > > > > > > > > > > > > > > cache to the remote tier." It needs to
> > copy
> > > > the
> > > > > > > > > producer
> > > > > > > > > > > snapshot
> > > > > > > > > > > > > > > too.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Right. It copies producer snapshots too
> > as
> > > > > > > mentioned in
> > > > > > > > > > > > > > > LogSegmentData.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 603.2 "Local logs are not cleaned up
> till
> > > > those
> > > > > > > > > segments
> > > > > > > > > > > are
> > > > > > > > > > > > > > copied
> > > > > > > > > > > > > > > > > > > successfully to remote even though
> their
> > > > > > retention
> > > > > > > > > > > time/size is
> > > > > > > > > > > > > > > reached"
> > > > > > > > > > > > > > > > > > > This seems weird. If the tiering stops
> > > > because
> > > > > > the
> > > > > > > > > remote
> > > > > > > > > > > store
> > > > > > > > > > > > > > is
> > > > > > > > > > > > > > > not
> > > > > > > > > > > > > > > > > > > available, we don't want the local data
> > to
> > > > grow
> > > > > > > > > forever.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > It was clarified in the discussion that
> > the
> > > > > > > comment was
> > > > > > > > > > > more
> > > > > > > > > > > > > > about
> > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > local storage goes beyond the
> > log.retention.
> > > > The
> > > > > > > above
> > > > > > > > > > > statement
> > > > > > > > > > > > > > > is about
> > > > > > > > > > > > > > > > > > > local.log.retention but not for the
> > complete
> > > > > > > > > > > log.retention. When
> > > > > > > > > > > > > > it
> > > > > > > > > > > > > > > > > > > reaches the log.retention then it will
> > > > delete the
> > > > > > > local
> > > > > > > > > > > logs even
> > > > > > > > > > > > > > > though
> > > > > > > > > > > > > > > > > > > those are not copied to remote storage.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 604. "RLM maintains a bounded
> > cache(possibly
> > > > LRU)
> > > > > > > of
> > > > > > > > > the
> > > > > > > > > > > index
> > > > > > > > > > > > > > > files of
> > > > > > > > > > > > > > > > > > > remote log segments to avoid multiple
> > index
> > > > > > fetches
> > > > > > > > > from
> > > > > > > > > > > the
> > > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > > > storage. These indexes can be used in
> the
> > > > same
> > > > > > way
> > > > > > > as
> > > > > > > > > local
> > > > > > > > > > > > > > segment
> > > > > > > > > > > > > > > > > > > indexes are used." Could you provide
> more
> > > > details
> > > > > > > on
> > > > > > > > > this?
> > > > > > > > > > > Are
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > indexes
> > > > > > > > > > > > > > > > > > > cached in memory or on disk? If on
> disk,
> > > > where
> > > > > > are
> > > > > > > they
> > > > > > > > > > > stored?
> > > > > > > > > > > > > > > Are the
> > > > > > > > > > > > > > > > > > > cached indexes bound by a certain size?
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > These are cached on disk and stored in
> > > > log.dir
> > > > > > > with a
> > > > > > > > > name
> > > > > > > > > > > > > > > > > > > “__remote_log_index_cache”. They are
> > bound
> > > > by the
> > > > > > > total
> > > > > > > > > > > size.
> > > > > > > > > > > > > > This
> > > > > > > > > > > > > > > will
> > > > > > > > > > > > > > > > > > be
> > > > > > > > > > > > > > > > > > > exposed as a user configuration,
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 605. BuildingRemoteLogAux
> > > > > > > > > > > > > > > > > > > 605.1 In this section, two options are
> > > > listed.
> > > > > > > Which
> > > > > > > > > one is
> > > > > > > > > > > > > > chosen?
> > > > > > > > > > > > > > > > > > > Option-2, updated the KIP.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 605.2 In option 2, it says "Build the
> > local
> > > > > > leader
> > > > > > > > > epoch
> > > > > > > > > > > cache by
> > > > > > > > > > > > > > > cutting
> > > > > > > > > > > > > > > > > > > the leader epoch sequence received from
> > > > remote
> > > > > > > storage
> > > > > > > > > to
> > > > > > > > > > > [LSO,
> > > > > > > > > > > > > > > ELO].
> > > > > > > > > > > > > > > > > > (LSO
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > = log start offset)." We need to do the
> > same
> > > > > > thing
> > > > > > > for
> > > > > > > > > the
> > > > > > > > > > > > > > producer
> > > > > > > > > > > > > > > > > > > snapshot. However, it's hard to cut the
> > > > producer
> > > > > > > > > snapshot
> > > > > > > > > > > to an
> > > > > > > > > > > > > > > earlier
> > > > > > > > > > > > > > > > > > > offset. Another option is to simply
> take
> > the
> > > > > > > lastOffset
> > > > > > > > > > > from the
> > > > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > > > segment and use that as the starting
> > fetch
> > > > offset
> > > > > > > in
> > > > > > > > > the
> > > > > > > > > > > > > > follower.
> > > > > > > > > > > > > > > This
> > > > > > > > > > > > > > > > > > > avoids the need for cutting.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Right, this was mentioned in the
> > > > “transactional
> > > > > > > > > support”
> > > > > > > > > > > section
> > > > > > > > > > > > > > > about
> > > > > > > > > > > > > > > > > > > adding these details.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 606. ListOffsets: Since we need a
> version
> > > > bump,
> > > > > > > could
> > > > > > > > > you
> > > > > > > > > > > > > > document
> > > > > > > > > > > > > > > it
> > > > > > > > > > > > > > > > > > > under a protocol change section?
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Sure, we will update the KIP.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 607. "LogStartOffset of a topic can
> > point to
> > > > > > > either of
> > > > > > > > > > > local
> > > > > > > > > > > > > > > segment or
> > > > > > > > > > > > > > > > > > > remote segment but it is initialised
> and
> > > > > > > maintained in
> > > > > > > > > the
> > > > > > > > > > > Log
> > > > > > > > > > > > > > > class like
> > > > > > > > > > > > > > > > > > > now. This is already maintained in
> `Log`
> > > > class
> > > > > > > while
> > > > > > > > > > > loading the
> > > > > > > > > > > > > > > logs and
> > > > > > > > > > > > > > > > > > > it can also be fetched from
> > > > > > > RemoteLogMetadataManager."
> > > > > > > > > > > What will
> > > > > > > > > > > > > > > happen
> > > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > > the existing logic (e.g. log recovery)
> > that
> > > > > > > currently
> > > > > > > > > > > depends on
> > > > > > > > > > > > > > > > > > > logStartOffset but assumes it's local?
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > They use a field called
> > localLogStartOffset
> > > > which
> > > > > > > is
> > > > > > > > > the
> > > > > > > > > > > local
> > > > > > > > > > > > > > log
> > > > > > > > > > > > > > > start
> > > > > > > > > > > > > > > > > > > offset..
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 608. Handle expired remote segment: How
> > does
> > > > it
> > > > > > > pick
> > > > > > > > > up new
> > > > > > > > > > > > > > > > > > logStartOffset
> > > > > > > > > > > > > > > > > > > from deleteRecords?
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Good point. This was not addressed in
> the
> > > > KIP.
> > > > > > Will
> > > > > > > > > update
> > > > > > > > > > > the
> > > > > > > > > > > > > > KIP
> > > > > > > > > > > > > > > on how
> > > > > > > > > > > > > > > > > > > the RLM task handles this scenario.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 609. RLMM message format:
> > > > > > > > > > > > > > > > > > > 609.1 It includes both MaxTimestamp and
> > > > > > > EventTimestamp.
> > > > > > > > > > > Where
> > > > > > > > > > > > > > does
> > > > > > > > > > > > > > > it get
> > > > > > > > > > > > > > > > > > > both since the message in the log only
> > > > contains
> > > > > > one
> > > > > > > > > > > timestamp?
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > `EventTimeStamp` is the timestamp at
> > which
> > > > that
> > > > > > > segment
> > > > > > > > > > > metadata
> > > > > > > > > > > > > > > event is
> > > > > > > > > > > > > > > > > > > generated. This is more for audits.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 609.2 If we change just the state (e.g.
> > to
> > > > > > > > > > > DELETE_STARTED), it
> > > > > > > > > > > > > > > seems it's
> > > > > > > > > > > > > > > > > > > wasteful to have to include all other
> > fields
> > > > not
> > > > > > > > > changed.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > This is a good point. We thought about
> > > > > > incremental
> > > > > > > > > > > updates. But
> > > > > > > > > > > > > > we
> > > > > > > > > > > > > > > want
> > > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > > make sure all the events are in the
> > expected
> > > > > > order
> > > > > > > and
> > > > > > > > > take
> > > > > > > > > > > > > > action
> > > > > > > > > > > > > > > based
> > > > > > > > > > > > > > > > > > > on the latest event. Will think through
> > the
> > > > > > > approaches
> > > > > > > > > in
> > > > > > > > > > > detail
> > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > update here.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 609.3 Could you document which process
> > makes
> > > > the
> > > > > > > > > following
> > > > > > > > > > > > > > > transitions
> > > > > > > > > > > > > > > > > > > DELETE_MARKED, DELETE_STARTED,
> > > > DELETE_FINISHED?
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Okay, will document more details.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 610.
> remote.log.reader.max.pending.tasks:
> > > > > > "Maximum
> > > > > > > > > remote
> > > > > > > > > > > log
> > > > > > > > > > > > > > > reader
> > > > > > > > > > > > > > > > > > > thread pool task queue size. If the
> task
> > > > queue is
> > > > > > > full,
> > > > > > > > > > > broker
> > > > > > > > > > > > > > > will stop
> > > > > > > > > > > > > > > > > > > reading remote log segments." What does
> > the
> > > > > > broker
> > > > > > > do
> > > > > > > > > if
> > > > > > > > > > > the
> > > > > > > > > > > > > > queue
> > > > > > > > > > > > > > > is
> > > > > > > > > > > > > > > > > > > full?
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > It returns an error for this topic
> > partition.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 611. What do we return if the request
> > > > > > offset/epoch
> > > > > > > > > doesn't
> > > > > > > > > > > exist
> > > > > > > > > > > > > > > in the
> > > > > > > > > > > > > > > > > > > following API?
> > > > > > > > > > > > > > > > > > > RemoteLogSegmentMetadata
> > > > > > > > > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > > > > > > > > > > > topicPartition, long offset, int
> > > > epochForOffset)
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > This returns null. But we prefer to
> > update
> > > > the
> > > > > > > return
> > > > > > > > > type
> > > > > > > > > > > as
> > > > > > > > > > > > > > > Optional
> > > > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > return Empty if that does not exist.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > > > > Satish.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > On Tue, Sep 1, 2020 at 9:45 AM Jun Rao
> <
> > jun@
> > > > > > > > > confluent.
> > > > > > > > > > > io (
> > > > > > > > > > > > > > > > > > > jun@confluent.io ) > wrote:
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >> Hi, Satish,
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >> Thanks for the updated KIP. Made
> another
> > > > pass. A
> > > > > > > few
> > > > > > > > > more
> > > > > > > > > > > > > > comments
> > > > > > > > > > > > > > > > > > below.
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >> 600. The topic deletion logic needs
> more
> > > > > > details.
> > > > > > > > > > > > > > > > > > >> 600.1 The KIP mentions "The controller
> > > > considers
> > > > > > > the
> > > > > > > > > topic
> > > > > > > > > > > > > > > partition is
> > > > > > > > > > > > > > > > > > >> deleted only when it determines that
> > there
> > > > are
> > > > > > no
> > > > > > > log
> > > > > > > > > > > segments
> > > > > > > > > > > > > > > for that
> > > > > > > > > > > > > > > > > > >> topic partition by using RLMM". How is
> > this
> > > > > > done?
> > > > > > > > > 600.2
> > > > > > > > > > > "If the
> > > > > > > > > > > > > > > delete
> > > > > > > > > > > > > > > > > > >> option is enabled then the leader will
> > stop
> > > > RLM
> > > > > > > task
> > > > > > > > > and
> > > > > > > > > > > stop
> > > > > > > > > > > > > > > processing
> > > > > > > > > > > > > > > > > > >> and it sets all the remote log segment
> > > > metadata
> > > > > > of
> > > > > > > > > that
> > > > > > > > > > > > > > partition
> > > > > > > > > > > > > > > with a
> > > > > > > > > > > > > > > > > > >> delete marker and publishes them to
> > RLMM."
> > > > We
> > > > > > > > > discussed
> > > > > > > > > > > this
> > > > > > > > > > > > > > > earlier.
> > > > > > > > > > > > > > > > > > When
> > > > > > > > > > > > > > > > > > >> a topic is being deleted, there may
> not
> > be a
> > > > > > > leader
> > > > > > > > > for
> > > > > > > > > > > the
> > > > > > > > > > > > > > > deleted
> > > > > > > > > > > > > > > > > > >> partition.
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >> 601. Unclean leader election
> > > > > > > > > > > > > > > > > > >> 601.1 Scenario 1: new empty follower
> > > > > > > > > > > > > > > > > > >> After step 1, the follower restores up
> > to
> > > > offset
> > > > > > > 3. So
> > > > > > > > > > > why does
> > > > > > > > > > > > > > > it have
> > > > > > > > > > > > > > > > > > >> LE-2 <
> > > > > > https://issues.apache.org/jira/browse/LE-2>
> > > > > > > at
> > > > > > > > > > > offset 5?
> > > > > > > > > > > > > > > > > > >> 601.2 senario 5: After Step 3, leader
> A
> > has
> > > > > > > > > inconsistent
> > > > > > > > > > > data
> > > > > > > > > > > > > > > between
> > > > > > > > > > > > > > > > > > its
> > > > > > > > > > > > > > > > > > >> local and the tiered data. For
> example.
> > > > offset 3
> > > > > > > has
> > > > > > > > > msg
> > > > > > > > > > > 3 LE-0
> > > > > > > > > > > > > > > <https://issues.apache.org/jira/browse/LE-0>
> > > > locally,
> > > > > > > > > > > > > > > > > > >> but msg 5 LE-1 <
> > > > > > > > > > > https://issues.apache.org/jira/browse/LE-1> in
> > > > > > > > > > > > > > > the remote store. While it's ok for the unclean
> > > > leader
> > > > > > > > > > > > > > > > > > >> to lose data, it should still return
> > > > consistent
> > > > > > > data,
> > > > > > > > > > > whether
> > > > > > > > > > > > > > > it's from
> > > > > > > > > > > > > > > > > > >> the local or the remote store.
> > > > > > > > > > > > > > > > > > >> 601.3 The follower picks up log start
> > offset
> > > > > > > using the
> > > > > > > > > > > following
> > > > > > > > > > > > > > > api.
> > > > > > > > > > > > > > > > > > >> Suppose that we have 3 remote segments
> > (LE,
> > > > > > > > > > > SegmentStartOffset)
> > > > > > > > > > > > > > > as (2,
> > > > > > > > > > > > > > > > > > >> 10),
> > > > > > > > > > > > > > > > > > >> (3, 20) and (7, 15) due to an unclean
> > leader
> > > > > > > election.
> > > > > > > > > > > Using the
> > > > > > > > > > > > > > > > > > following
> > > > > > > > > > > > > > > > > > >> api will cause logStartOffset to go
> > backward
> > > > > > from
> > > > > > > 20
> > > > > > > > > to
> > > > > > > > > > > 15. How
> > > > > > > > > > > > > > > do we
> > > > > > > > > > > > > > > > > > >> prevent that?
> > > > > > > > > > > > > > > > > > >> earliestLogOffset(TopicPartition
> > > > topicPartition,
> > > > > > > int
> > > > > > > > > > > > > > leaderEpoch)
> > > > > > > > > > > > > > > 601.4
> > > > > > > > > > > > > > > > > > It
> > > > > > > > > > > > > > > > > > >> seems that retention is based on
> > > > > > > > > > > > > > > > > > >> listRemoteLogSegments(TopicPartition
> > > > > > > topicPartition,
> > > > > > > > > long
> > > > > > > > > > > > > > > leaderEpoch).
> > > > > > > > > > > > > > > > > > >> When there is an unclean leader
> > election,
> > > > it's
> > > > > > > > > possible
> > > > > > > > > > > for the
> > > > > > > > > > > > > > > new
> > > > > > > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > > > >> to not to include certain epochs in
> its
> > > > epoch
> > > > > > > cache.
> > > > > > > > > How
> > > > > > > > > > > are
> > > > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > > >> segments associated with those epochs
> > being
> > > > > > > cleaned?
> > > > > > > > > > > 601.5 The
> > > > > > > > > > > > > > KIP
> > > > > > > > > > > > > > > > > > >> discusses the handling of unclean
> leader
> > > > > > > elections for
> > > > > > > > > > > user
> > > > > > > > > > > > > > > topics. What
> > > > > > > > > > > > > > > > > > >> about unclean leader elections on
> > > > > > > > > > > > > > > > > > >> __remote_log_segment_metadata?
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >> 602. It would be useful to clarify the
> > > > > > > limitations in
> > > > > > > > > the
> > > > > > > > > > > > > > initial
> > > > > > > > > > > > > > > > > > release.
> > > > > > > > > > > > > > > > > > >> The KIP mentions not supporting
> > compacted
> > > > > > topics.
> > > > > > > What
> > > > > > > > > > > about
> > > > > > > > > > > > > > JBOD
> > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > >> changing the configuration of a topic
> > from
> > > > > > delete
> > > > > > > to
> > > > > > > > > > > compact
> > > > > > > > > > > > > > after
> > > > > > > > > > > > > > > > > > remote.
> > > > > > > > > > > > > > > > > > >> log. storage. enable (
> > > > > > > > > http://remote.log.storage.enable/
> > > > > > > > > > > ) is
> > > > > > > > > > > > > > > enabled?
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >> 603. RLM leader tasks:
> > > > > > > > > > > > > > > > > > >> 603.1"It checks for rolled over
> > LogSegments
> > > > > > (which
> > > > > > > > > have
> > > > > > > > > > > the last
> > > > > > > > > > > > > > > message
> > > > > > > > > > > > > > > > > > >> offset less than last stable offset of
> > that
> > > > > > topic
> > > > > > > > > > > partition) and
> > > > > > > > > > > > > > > copies
> > > > > > > > > > > > > > > > > > >> them along with their
> > > > offset/time/transaction
> > > > > > > indexes
> > > > > > > > > and
> > > > > > > > > > > leader
> > > > > > > > > > > > > > > epoch
> > > > > > > > > > > > > > > > > > >> cache to the remote tier." It needs to
> > copy
> > > > the
> > > > > > > > > producer
> > > > > > > > > > > > > > snapshot
> > > > > > > > > > > > > > > too.
> > > > > > > > > > > > > > > > > > >> 603.2 "Local logs are not cleaned up
> > till
> > > > those
> > > > > > > > > segments
> > > > > > > > > > > are
> > > > > > > > > > > > > > > copied
> > > > > > > > > > > > > > > > > > >> successfully to remote even though
> their
> > > > > > retention
> > > > > > > > > > > time/size is
> > > > > > > > > > > > > > > reached"
> > > > > > > > > > > > > > > > > > >> This seems weird. If the tiering stops
> > > > because
> > > > > > the
> > > > > > > > > remote
> > > > > > > > > > > store
> > > > > > > > > > > > > > > is not
> > > > > > > > > > > > > > > > > > >> available, we don't want the local
> data
> > to
> > > > grow
> > > > > > > > > forever.
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >> 604. "RLM maintains a bounded
> > cache(possibly
> > > > > > LRU)
> > > > > > > of
> > > > > > > > > the
> > > > > > > > > > > index
> > > > > > > > > > > > > > > files of
> > > > > > > > > > > > > > > > > > >> remote log segments to avoid multiple
> > index
> > > > > > > fetches
> > > > > > > > > from
> > > > > > > > > > > the
> > > > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > > >> storage. These indexes can be used in
> > the
> > > > same
> > > > > > > way as
> > > > > > > > > > > local
> > > > > > > > > > > > > > > segment
> > > > > > > > > > > > > > > > > > >> indexes are used." Could you provide
> > more
> > > > > > details
> > > > > > > on
> > > > > > > > > > > this? Are
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > indexes
> > > > > > > > > > > > > > > > > > >> cached in memory or on disk? If on
> disk,
> > > > where
> > > > > > are
> > > > > > > > > they
> > > > > > > > > > > stored?
> > > > > > > > > > > > > > > Are the
> > > > > > > > > > > > > > > > > > >> cached indexes bound by a certain
> size?
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >> 605. BuildingRemoteLogAux
> > > > > > > > > > > > > > > > > > >> 605.1 In this section, two options are
> > > > listed.
> > > > > > > Which
> > > > > > > > > one
> > > > > > > > > > > is
> > > > > > > > > > > > > > > chosen?
> > > > > > > > > > > > > > > > > > 605.2
> > > > > > > > > > > > > > > > > > >> In option 2, it says "Build the local
> > leader
> > > > > > epoch
> > > > > > > > > cache
> > > > > > > > > > > by
> > > > > > > > > > > > > > > cutting the
> > > > > > > > > > > > > > > > > > >> leader epoch sequence received from
> > remote
> > > > > > > storage to
> > > > > > > > > > > [LSO,
> > > > > > > > > > > > > > ELO].
> > > > > > > > > > > > > > > (LSO
> > > > > > > > > > > > > > > > > > >> = log start offset)." We need to do
> the
> > same
> > > > > > thing
> > > > > > > > > for the
> > > > > > > > > > > > > > > producer
> > > > > > > > > > > > > > > > > > >> snapshot. However, it's hard to cut
> the
> > > > producer
> > > > > > > > > snapshot
> > > > > > > > > > > to an
> > > > > > > > > > > > > > > earlier
> > > > > > > > > > > > > > > > > > >> offset. Another option is to simply
> > take the
> > > > > > > > > lastOffset
> > > > > > > > > > > from the
> > > > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > > >> segment and use that as the starting
> > fetch
> > > > > > offset
> > > > > > > in
> > > > > > > > > the
> > > > > > > > > > > > > > > follower. This
> > > > > > > > > > > > > > > > > > >> avoids the need for cutting.
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >> 606. ListOffsets: Since we need a
> > version
> > > > bump,
> > > > > > > could
> > > > > > > > > you
> > > > > > > > > > > > > > > document it
> > > > > > > > > > > > > > > > > > >> under a protocol change section?
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >> 607. "LogStartOffset of a topic can
> > point to
> > > > > > > either of
> > > > > > > > > > > local
> > > > > > > > > > > > > > > segment or
> > > > > > > > > > > > > > > > > > >> remote segment but it is initialised
> and
> > > > > > > maintained in
> > > > > > > > > > > the Log
> > > > > > > > > > > > > > > class
> > > > > > > > > > > > > > > > > > like
> > > > > > > > > > > > > > > > > > >> now. This is already maintained in
> `Log`
> > > > class
> > > > > > > while
> > > > > > > > > > > loading the
> > > > > > > > > > > > > > > logs
> > > > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > >> it can also be fetched from
> > > > > > > RemoteLogMetadataManager."
> > > > > > > > > > > What will
> > > > > > > > > > > > > > > happen
> > > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > >> the existing logic (e.g. log recovery)
> > that
> > > > > > > currently
> > > > > > > > > > > depends on
> > > > > > > > > > > > > > > > > > >> logStartOffset but assumes it's local?
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >> 608. Handle expired remote segment:
> How
> > > > does it
> > > > > > > pick
> > > > > > > > > up
> > > > > > > > > > > new
> > > > > > > > > > > > > > > > > > logStartOffset
> > > > > > > > > > > > > > > > > > >> from deleteRecords?
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >> 609. RLMM message format:
> > > > > > > > > > > > > > > > > > >> 609.1 It includes both MaxTimestamp
> and
> > > > > > > > > EventTimestamp.
> > > > > > > > > > > Where
> > > > > > > > > > > > > > > does it
> > > > > > > > > > > > > > > > > > get
> > > > > > > > > > > > > > > > > > >> both since the message in the log only
> > > > contains
> > > > > > > one
> > > > > > > > > > > timestamp?
> > > > > > > > > > > > > > > 609.2 If
> > > > > > > > > > > > > > > > > > we
> > > > > > > > > > > > > > > > > > >> change just the state (e.g. to
> > > > DELETE_STARTED),
> > > > > > it
> > > > > > > > > seems
> > > > > > > > > > > it's
> > > > > > > > > > > > > > > wasteful
> > > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > >> have to include all other fields not
> > > > changed.
> > > > > > > 609.3
> > > > > > > > > Could
> > > > > > > > > > > you
> > > > > > > > > > > > > > > document
> > > > > > > > > > > > > > > > > > >> which process makes the following
> > > > transitions
> > > > > > > > > > > DELETE_MARKED,
> > > > > > > > > > > > > > > > > > >> DELETE_STARTED, DELETE_FINISHED?
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >> 610.
> > remote.log.reader.max.pending.tasks:
> > > > > > "Maximum
> > > > > > > > > remote
> > > > > > > > > > > log
> > > > > > > > > > > > > > > reader
> > > > > > > > > > > > > > > > > > >> thread pool task queue size. If the
> task
> > > > queue
> > > > > > is
> > > > > > > > > full,
> > > > > > > > > > > broker
> > > > > > > > > > > > > > > will stop
> > > > > > > > > > > > > > > > > > >> reading remote log segments." What
> does
> > the
> > > > > > > broker do
> > > > > > > > > if
> > > > > > > > > > > the
> > > > > > > > > > > > > > > queue is
> > > > > > > > > > > > > > > > > > >> full?
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >> 611. What do we return if the request
> > > > > > offset/epoch
> > > > > > > > > > > doesn't exist
> > > > > > > > > > > > > > > in the
> > > > > > > > > > > > > > > > > > >> following API?
> > > > > > > > > > > > > > > > > > >> RemoteLogSegmentMetadata
> > > > > > > > > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > > > > > > > > > > >> topicPartition, long offset, int
> > > > epochForOffset)
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >> Jun
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >> On Mon, Aug 31, 2020 at 11:19 AM
> Satish
> > > > Duggana
> > > > > > <
> > > > > > > > > satish.
> > > > > > > > > > > > > > duggana@
> > > > > > > > > > > > > > > > > > gmail. com
> > > > > > > > > > > > > > > > > > >> ( satish.duggana@gmail.com ) > wrote:
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>> KIP is updated with
> > > > > > > > > > > > > > > > > > >>> - Remote log segment metadata topic
> > message
> > > > > > > > > > > format/schema.
> > > > > > > > > > > > > > > > > > >>> - Added remote log segment metadata
> > state
> > > > > > > > > transitions and
> > > > > > > > > > > > > > > explained how
> > > > > > > > > > > > > > > > > > >>> the deletion of segments is handled,
> > > > including
> > > > > > > the
> > > > > > > > > case
> > > > > > > > > > > of
> > > > > > > > > > > > > > > partition
> > > > > > > > > > > > > > > > > > >>> deletions.
> > > > > > > > > > > > > > > > > > >>> - Added a few more limitations in the
> > "Non
> > > > > > goals"
> > > > > > > > > > > section.
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>> Thanks,
> > > > > > > > > > > > > > > > > > >>> Satish.
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>> On Thu, Aug 27, 2020 at 12:42 AM
> > Harsha Ch
> > > > <
> > > > > > > harsha.
> > > > > > > > > ch@
> > > > > > > > > > > > > > gmail.
> > > > > > > > > > > > > > > com (
> > > > > > > > > > > > > > > > > > >>> harsha.ch@gmail.com ) > wrote:
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>> Updated the KIP with Meeting Notes
> > section
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>> https:/ / cwiki. apache. org/
> > confluence/
> > > > > > > display/
> > > > > > > > > KAFKA/
> > > > > > > > > > > > > > > > > > KIP-405 <
> > > > > > > https://issues.apache.org/jira/browse/KIP-405>
> > > > > > > > > > > > > > >
> > > > > > > %3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> > > > > > > > > > > > > > > > > > >>> (
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > >
> > > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-405%3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> > > > > > > > > > > > > > > > > > >>> )
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>> On Tue, Aug 25, 2020 at 1:03 PM Jun
> > Rao <
> > > > jun@
> > > > > > > > > > > confluent. io
> > > > > > > > > > > > > > (
> > > > > > > > > > > > > > > > > > >>>> jun@confluent.io ) > wrote:
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>> Hi, Harsha,
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>> Thanks for the summary. Could you
> > add the
> > > > > > > summary
> > > > > > > > > and
> > > > > > > > > > > the
> > > > > > > > > > > > > > > recording
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>> link to
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>> the last section of
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>> https:/ / cwiki. apache. org/
> > confluence/
> > > > > > > display/
> > > > > > > > > KAFKA/
> > > > > > > > > > > > > > > > > > Kafka+Improvement+Proposals
> > > > > > > > > > > > > > > > > > >>> (
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > >
> > > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/Kafka+Improvement+Proposals
> > > > > > > > > > > > > > > > > > >>> )
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>> ?
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>> Jun
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>> On Tue, Aug 25, 2020 at 11:12 AM
> > Harsha
> > > > > > > > > Chintalapani <
> > > > > > > > > > > kafka@
> > > > > > > > > > > > > > > > > > harsha. io (
> > > > > > > > > > > > > > > > > > >>>>> kafka@harsha.io ) > wrote:
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>> Thanks everyone for attending the
> > > > meeting
> > > > > > > today.
> > > > > > > > > > > > > > > > > > >>>>>> Here is the recording
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>> https:/ / drive. google. com/ file/
> d/
> > > > > > > > > > > > > > > > > > 14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/
> > > > view?usp=sharing
> > > > > > > > > > > > > > > > > > >>> (
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > >
> > > >
> >
> https://drive.google.com/file/d/14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/view?usp=sharing
> > > > > > > > > > > > > > > > > > >>> )
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>> Notes:
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>> 1. KIP is updated with follower
> > fetch
> > > > > > > protocol and
> > > > > > > > > > > ready to
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>> reviewed
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>> 2. Satish to capture schema of
> > internal
> > > > > > > metadata
> > > > > > > > > > > topic in
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > KIP
> > > > > > > > > > > > > > > > > > >>>>>> 3. We will update the KIP with
> > details
> > > > of
> > > > > > > > > different
> > > > > > > > > > > cases
> > > > > > > > > > > > > > > > > > >>>>>> 4. Test plan will be captured in a
> > doc
> > > > and
> > > > > > > will
> > > > > > > > > add
> > > > > > > > > > > to the
> > > > > > > > > > > > > > KIP
> > > > > > > > > > > > > > > > > > >>>>>> 5. Add a section "Limitations" to
> > > > capture
> > > > > > the
> > > > > > > > > > > capabilities
> > > > > > > > > > > > > > > that
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>> will
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>> be
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>> introduced with this KIP and what
> > will
> > > > not
> > > > > > be
> > > > > > > > > covered
> > > > > > > > > > > in
> > > > > > > > > > > > > > this
> > > > > > > > > > > > > > > KIP.
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>> Please add to it I missed
> anything.
> > Will
> > > > > > > produce a
> > > > > > > > > > > formal
> > > > > > > > > > > > > > > meeting
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>> notes
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>> from next meeting onwards.
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>> Thanks,
> > > > > > > > > > > > > > > > > > >>>>>> Harsha
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>> On Mon, Aug 24, 2020 at 9:42 PM,
> > Ying
> > > > Zheng
> > > > > > <
> > > > > > > > > yingz@
> > > > > > > > > > > uber.
> > > > > > > > > > > > > > > com.
> > > > > > > > > > > > > > > > > > invalid (
> > > > > > > > > > > > > > > > > > >>>>>> yingz@uber.com.invalid ) > wrote:
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> We did some basic feature tests
> at
> > > > Uber.
> > > > > > The
> > > > > > > test
> > > > > > > > > > > cases and
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>> results are
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> shared in this google doc:
> > > > > > > > > > > > > > > > > > >>>>>>> https:/ / docs. google. com/
> > > > spreadsheets/
> > > > > > > d/ (
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > https://docs.google.com/spreadsheets/d/ )
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >
> > > > > > 1XhNJqjzwXvMCcAOhEH0sSXU6RTvyoSf93DHF-YMfGLk/edit?usp=sharing
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> The performance test results were
> > > > already
> > > > > > > shared
> > > > > > > > > in
> > > > > > > > > > > the KIP
> > > > > > > > > > > > > > > last
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>> month.
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> On Mon, Aug 24, 2020 at 11:10 AM
> > > > Harsha Ch
> > > > > > <
> > > > > > > > > harsha.
> > > > > > > > > > > ch@
> > > > > > > > > > > > > > > gmail.
> > > > > > > > > > > > > > > > > > com (
> > > > > > > > > > > > > > > > > > >>>>>>> harsha.ch@gmail.com ) >
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>> wrote:
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> "Understand commitments towards
> > driving
> > > > > > > design &
> > > > > > > > > > > > > > > implementation of
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>> the
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>> KIP
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> further and how it aligns with
> > > > participant
> > > > > > > > > interests
> > > > > > > > > > > in
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>> contributing to
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>> the
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> efforts (ex: in the context of
> > Uber’s
> > > > Q3/Q4
> > > > > > > > > > > roadmap)." What
> > > > > > > > > > > > > > > is that
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>> about?
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> On Mon, Aug 24, 2020 at 11:05 AM
> > > > Kowshik
> > > > > > > > > Prakasam <
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>> kprakasam@ confluent. io (
> > > > > > > kprakasam@confluent.io
> > > > > > > > > ) >
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> wrote:
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> Hi Harsha,
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> The following google doc
> contains a
> > > > > > proposal
> > > > > > > for
> > > > > > > > > > > temporary
> > > > > > > > > > > > > > > agenda
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>> for
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>> the
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> KIP-405 <
> > > > > > > > > > > https://issues.apache.org/jira/browse/KIP-405> <
> > > > > > > > > > > > > > > https:/ / issues. apache. org/ jira/ browse/
> > KIP-405
> > > > > > > > > > > > > > > <https://issues.apache.org/jira/browse/KIP-405
> >
> > (
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > https://issues.apache.org/jira/browse/KIP-405 )
> > > > > > > > > >
> > > > > > > > > > > sync
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>> meeting
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> tomorrow:
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> https:/ / docs. google. com/
> > document/
> > > > d/ (
> > > > > > > > > > > > > > > > > > >>>>>>>
> > https://docs.google.com/document/d/ )
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > 1pqo8X5LU8TpwfC_iqSuVPezhfCfhGkbGN2TqiPA3LBU/edit
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> .
> > > > > > > > > > > > > > > > > > >>>>>>> Please could you add it to the
> > Google
> > > > > > > calendar
> > > > > > > > > > > invite?
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> Thank you.
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> Cheers,
> > > > > > > > > > > > > > > > > > >>>>>>> Kowshik
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> On Thu, Aug 20, 2020 at 10:58 AM
> > > > Harsha Ch
> > > > > > <
> > > > > > > > > harsha.
> > > > > > > > > > > ch@
> > > > > > > > > > > > > > > gmail.
> > > > > > > > > > > > > > > > > > com (
> > > > > > > > > > > > > > > > > > >>>>>>> harsha.ch@gmail.com ) >
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>> wrote:
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> Hi All,
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> Scheduled a meeting for Tuesday
> > 9am -
> > > > 10am.
> > > > > > > I can
> > > > > > > > > > > record
> > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>> upload for
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> community to be able to follow
> the
> > > > > > > discussion.
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> Jun, please add the required
> folks
> > on
> > > > > > > confluent
> > > > > > > > > side.
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> Thanks,
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> Harsha
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> On Thu, Aug 20, 2020 at 12:33 AM,
> > > > Alexandre
> > > > > > > > > Dupriez <
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>> alexandre.dupriez@
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> gmail. com ( http://gmail.com/
> ) >
> > > > wrote:
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> Hi Jun,
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> Many thanks for your initiative.
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> If you like, I am happy to attend
> > at
> > > > the
> > > > > > > time you
> > > > > > > > > > > > > > suggested.
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> Many thanks,
> > > > > > > > > > > > > > > > > > >>>>>>> Alexandre
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> Le mer. 19 août 2020 à 22:00,
> > Harsha
> > > > Ch <
> > > > > > > > > harsha. ch@
> > > > > > > > > > > > > > > gmail. com (
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>> harsha.
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> ch@ gmail. com ( ch@gmail.com )
> )
> > > a
> > > > > > écrit
> > > > > > > :
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> Hi Jun,
> > > > > > > > > > > > > > > > > > >>>>>>> Thanks. This will help a lot.
> > Tuesday
> > > > will
> > > > > > > work
> > > > > > > > > for
> > > > > > > > > > > us.
> > > > > > > > > > > > > > > > > > >>>>>>> -Harsha
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> On Wed, Aug 19, 2020 at 1:24 PM
> Jun
> > > > Rao <
> > > > > > > jun@
> > > > > > > > > > > confluent.
> > > > > > > > > > > > > > > io (
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>> jun@
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> confluent. io (
> > http://confluent.io/
> > > > ) ) >
> > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> Hi, Satish, Ying, Harsha,
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> Do you think it would be useful
> to
> > > > have a
> > > > > > > regular
> > > > > > > > > > > virtual
> > > > > > > > > > > > > > > meeting
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>> to
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> discuss this KIP? The goal of the
> > > > meeting
> > > > > > > will be
> > > > > > > > > > > sharing
> > > > > > > > > > > > > > > > > > >>>>>>> design/development progress and
> > > > discussing
> > > > > > > any
> > > > > > > > > open
> > > > > > > > > > > issues
> > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> accelerate
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> this KIP. If so, will every
> Tuesday
> > > > (from
> > > > > > > next
> > > > > > > > > week)
> > > > > > > > > > > > > > 9am-10am
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> PT
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> work for you? I can help set up a
> > Zoom
> > > > > > > meeting,
> > > > > > > > > > > invite
> > > > > > > > > > > > > > > everyone who
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> might
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> be interested, have it recorded
> and
> > > > shared,
> > > > > > > etc.
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> Thanks,
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> Jun
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> On Tue, Aug 18, 2020 at 11:01 AM
> > Satish
> > > > > > > Duggana <
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> satish. duggana@ gmail. com (
> > satish.
> > > > > > > duggana@
> > > > > > > > > > > gmail. com
> > > > > > > > > > > > > > (
> > > > > > > > > > > > > > > > > > >>>>>>> satish.duggana@gmail.com ) ) >
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> wrote:
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> Hi Kowshik,
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> Thanks for looking into the KIP
> and
> > > > sending
> > > > > > > your
> > > > > > > > > > > comments.
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> 5001. Under the section "Follower
> > fetch
> > > > > > > protocol
> > > > > > > > > in
> > > > > > > > > > > > > > detail",
> > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > >>>>>>> next-local-offset is the offset
> > upto
> > > > which
> > > > > > > the
> > > > > > > > > > > segments are
> > > > > > > > > > > > > > > copied
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > >
> > > >
> >
>

Re: [DISCUSS] KIP-405: Kafka Tiered Storage

[Satish Duggana <sa...@gmail.com>]

Hi Jun,
Thanks for your reply.  Most of these were discussed in our earlier
syncup, updating here in the mail thread too.

6000. When RSM/RLMM is not available, it seems that we need to return a
retriable error to the affected client requests. So, should we add a new
error code for requests like fetch and listOffset?

When RSM/RLMM is not available, the existing KafkaStorageException is
used, which is a retriable error. It can be considered a storage error
as we could not get the data needed from remote storage or RLMM backed
storage.

9111. RemotePartitionRemover:
91111.1 Could we make it clear that it's part of the default RLMM
implementation and a separate implementation is needed if one has a
customized RLMM?

RemotePartitionRemover is part of default implementation of RLMM.
Custom RLMM implementors need to have a separate implementation of
deleting remote log segments when they receive delete partition state
events.

91111.2 "RPRM gets all the remote log segments for the partition using RLMM
and each of these remote log segments is deleted with the next steps.RLMM
subscribes to the local remote log metadata partitions and it will have the
segment metadata of all the user topic partitions associated with that
remote log metadata partition." It seems that RLMM needs to subscribe to
the remote log metadata partitions first before those segments can be
Deleted?

Yes, RLMM subscribes to local remote log metadata topic partitions.
RemotePartionRemover(RPRM) can get all the remote log segments from
RLMM when it needs to process delete partition marked events.

9111.3 There are still references to "remote log cleaners". They need to be
replaced with RemotePartitionRemover.

Nice catch, replaced those 2 occurrences.

9114.1 Could we add the requirement on log.message.format before enabling
tiered storage?

Updated the KIP.

9116. RemoteLogMetadataFormatter: This is used with the ConsoleConsumer
tool, right? Then, are those new options for ConsoleConsumer and how are
they passed in?

Right, these are for console consumer. It allows taking properties
through `property` flag and user needs to pass them while running
console consumer.


~Satish.

On Tue, 26 Jan 2021 at 01:12, Jun Rao <ju...@confluent.io> wrote:
>
> Hi, Satish,
>
> Thanks for the reply. A few more comments below.
>
> 6000. When RSM/RLMM is not available, it seems that we need to return a
> retriable error to the affected client requests. So, should we add a new
> error code for requests like fetch and listOffset?
>
> 9111. RemotePartitionRemover:
> 91111.1 Could we make it clear that it's part of the default RLMM
> implementation and a separate implementation is needed if one has a
> customized RLMM?
> 91111.2 "RPRM gets all the remote log segments for the partition using RLMM
> and each of these remote log segments is deleted with the next steps.RLMM
> subscribes to the local remote log metadata partitions and it will have the
> segment metadata of all the user topic partitions associated with that
> remote log metadata partition." It seems that RLMM needs to subscribe to
> the remote log metadata partitions first before those segments can be
> deleted?
> 9111.3 There are still references to "remote log cleaners". They need to be
> replaced with RemotePartitionRemover.
>
> 9114.1 Could we add the requirement on log.message.format before enabling
> tiered storage?
>
> 9116. RemoteLogMetadataFormatter: This is used with the ConsoleConsumer
> tool, right? Then, are those new options for ConsoleConsumer and how are
> they passed in?
>
> Thanks,
>
> Jun
>
>
> On Mon, Jan 25, 2021 at 8:02 AM Satish Duggana <sa...@gmail.com>
> wrote:
>
> > Hi Jun,
> >
> > Thanks for your comments. Please find the inline replies below.
> > Several of these were discussed/clarified in our last discussion.
> >
> > 6000. Since we are returning new error codes, we need to bump up the
> > protocol version for Fetch request. Also, it will be useful to document all
> > new error codes and whether they are retriable or not.
> > This previous comment doesn't seem to be addressed.
> >
> > Updated KIP on fetch protocol and error code.
> >
> > 9110. flat_file_format: Could you define the serialized representation for
> > each field in the header?
> >
> > Added the serialized representation types in the KIP.
> >
> > 9111. RPM has the following 2 steps.
> > "1. The controller publishes delete_partition_marked event to say that the
> > partition is marked for deletion. There can be multiple events published
> > when the controller restarts or failover and this event will be
> > deduplicated by RPM.
> > 2. RPM receives the delete_partition_marked and processes it if it is not
> > yet processed earlier."
> > What triggers RPM to read __remote_log_metadata? Is RPM part of the default
> > RLMM implementation or is it meant for any RLMM implementation?
> >
> > RPM(or RPRM) is only for the default RLMM implementation. RPM receives
> > the delete_partition_marked events from RLMM and acts on them. Updated
> > KIP with more details.
> >
> > 9112. remote.log.manager.task.retry.backoff.ms: It would be useful to make
> > it clear in the comment that this is for the initial retry backoff.
> >
> > Updated the KIP.
> >
> > 9113. RLMM:
> > 9113.1 updateRemoteLogSegmentMetadata(): This comment needs to be updated.
> >
> > Updated javadoc of this method.
> >
> > 9113.2 Should RemoteLogSegmentMetadataUpdate include a leadeEpoch field
> > since all other update events have leaderEpoch?
> >
> > +1 to have that,  updated the KIP.
> >
> > 9113.3 Could we rename RemotePartitionState to RemotePartitionDeleteState
> > to make it clear this is for deletion?
> >
> > Sure, updated the KIP.
> >
> > 9113.4 Could we rename RemoteLogState to RemoteLogSegmentState to make it
> > clear this is for segment?
> >
> > Sure, Updated the KIP.
> >
> > 9114.Upgrade:
> > 9114.1 It seems that we require message format > 0.11 for turning on the
> > remote store feature.
> >
> > 9114.2 It's not clear to me why remote.log.storage.system.enable needs to
> > be set to true before bumping up inter.broker.protocol.version.
> >
> > Agree that based on our discussion, this is not required. Upgrade
> > notes is updated.
> >
> > 9114.3 "If the topic-id is not received in the LeaderAndIsr request then
> > remote log storage will not start. But it will log an error message in the
> > log. One way to address this is to do a rolling restart of that broker, so
> > that the leader will be moved to another broker and the controller will
> > send LeaderAndIsr with the registered topic-id." Why is this needed? With
> > KIP-516, after upgrading to the latest protocol, topicIds are auto created.
> >
> > I thought there may be edge cases of not receiving topic-id but you
> > clarified in the meeting that won’t be the case. I agree that it is
> > not needed.
> >
> > 9115. testing: Could you comment on how we plan to do integration and
> > system tests? Do we plan to include, for example, an in-memory
> > implementation of RSM?
> >
> > For integration tests, we can have file based RSM that we have. For
> > system tests, we can have a single node HDFS cluster in one of the
> > containers and use HDFS RSM implementation.
> >
> > 9116. There is still a todo for the message formatter.
> >
> > Updated the KIP with the format.
> >
> >
> > Satish.
> >
> >
> > On Tue, 12 Jan 2021 at 07:07, Jun Rao <ju...@confluent.io> wrote:
> > >
> > > Hi, Satish,
> > >
> > > Thanks for the reply. A few more followup comments.
> > >
> > > 6000. Since we are returning new error codes, we need to bump up the
> > > protocol version for Fetch request. Also, it will be useful to document
> > all
> > > new error codes and whether they are retriable or not.
> > > This previous comment doesn't seem to be addressed.
> > >
> > > 9110. flat_file_format: Could you define the serialized representation
> > for
> > > each field in the header?
> > >
> > > 9111. RPM has the following 2 steps.
> > > "1. The controller publishes delete_partition_marked event to say that
> > the
> > > partition is marked for deletion. There can be multiple events published
> > > when the controller restarts or failover and this event will be
> > > deduplicated by RPM.
> > > 2. RPM receives the delete_partition_marked and processes it if it is not
> > > yet processed earlier."
> > > What triggers RPM to read __remote_log_metadata? Is RPM part of the
> > default
> > > RLMM implementation or is it meant for any RLMM implementation?
> > >
> > > 9112. remote.log.manager.task.retry.backoff.ms: It would be useful to
> > make
> > > it clear in the comment that this is for the initial retry backoff.
> > >
> > > 9113. RLMM:
> > > 9113.1 updateRemoteLogSegmentMetadata(): This comment needs to be
> > updated.
> > > 9113.2 Should RemoteLogSegmentMetadataUpdate include a leadeEpoch field
> > > since all other update events have leaderEpoch?
> > > 9113.3 Could we rename RemotePartitionState to RemotePartitionDeleteState
> > > to make it clear this is for deletion?
> > > 9113.4 Could we rename RemoteLogState to RemoteLogSegmentState to make it
> > > clear this is for segment?
> > >
> > > 9114.Upgrade:
> > > 9114.1 It seems that we require message format > 0.11 for turning on the
> > > remote store feature.
> > > 9114.2 It's not clear to me why remote.log.storage.system.enable needs to
> > > be set to true before bumping up inter.broker.protocol.version.
> > > 9114.3 "If the topic-id is not received in the LeaderAndIsr request then
> > > remote log storage will not start. But it will log an error message in
> > the
> > > log. One way to address this is to do a rolling restart of that broker,
> > so
> > > that the leader will be moved to another broker and the controller will
> > > send LeaderAndIsr with the registered topic-id." Why is this needed? With
> > > KIP-516, after upgrading to the latest protocol, topicIds are auto
> > created.
> > >
> > > 9115. testing: Could you comment on how we plan to do integration and
> > > system tests? Do we plan to include, for example, an in-memory
> > > implementation of RSM?
> > >
> > > 9116. There is still a todo for the message formatter.
> > >
> > > Jun
> > >
> > > On Sat, Jan 9, 2021 at 2:04 AM Satish Duggana <sa...@gmail.com>
> > > wrote:
> > >
> > > > Hi Jun,
> > > > Thanks for your comments. Please find the inline replies below.
> > > >
> > > > 6022. For packages used for server plugins, the convention is to
> > > > use org.apache.kafka.server. See java-based Authorizer as an example.
> > > >
> > > > Sure, ‘org.apache.kafka.common.log.remote.storage’ renamed to
> > > > ‘org.apache.kafka.server.log.remote.storage’.  Updated in the KIP.
> > > >
> > > > 9100. Do we need DeletePartitionStateRecord in flat_file_format? The
> > flat
> > > > file captures the state of the remote segments. After a partition is
> > > > deleted, it seems that we just need to remove the partitions's remote
> > > > segments from the flat file.
> > > >
> > > > DeletePartitionState might not yet have been processed by RPM and not
> > > > completed. We  will not have  that in flat  file format  once it
> > > > reaches DELETE_PARTITION_FINISHED state.
> > > >
> > > > 9101. Upgrade: It will be useful to allow direct upgrade from an old
> > > > version. It seems that's doable. One can just do the normal upgrade
> > first
> > > > and wait enough time (for producer snapshots to be built), and then
> > enable
> > > > remote storage.
> > > >
> > > > Upgrade notes updates in the KIP.
> > > >
> > > > 9102. RemotePartitionRemover(RPM) process: Is it true that RPM starts
> > > > tracking the remote segments when RLMM.onPartitionLeadershipChanges()
> > is
> > > > called with the broker being the leader for __remote_log_metadata
> > > > partition? If so, could we document it?
> > > >
> > > > The current plan is to have that as part of RLMM and RPM uses that to
> > > > get the remote segments list. I will add this detail in the respective
> > > > sections.
> > > >
> > > > Satish.
> > > >
> > > > On Wed, 16 Dec 2020 at 23:55, Jun Rao <ju...@confluent.io> wrote:
> > > > >
> > > > > Hi, Satish,
> > > > >
> > > > > Thanks for the reply. A few more followup comments.
> > > > >
> > > > > 6022. For packages used for server plugins, the convention is to
> > > > > use org.apache.kafka.server. See java-based Authorizer as an example.
> > > > >
> > > > > 9100. Do we need DeletePartitionStateRecord in flat_file_format? The
> > flat
> > > > > file captures the state of the remote segments. After a partition is
> > > > > deleted, it seems that we just need to remove the partitions's remote
> > > > > segments from the flat file.
> > > > >
> > > > > 9101. Upgrade: It will be useful to allow direct upgrade from an old
> > > > > version. It seems that's doable. One can just do the normal upgrade
> > first
> > > > > and wait enough time (for producer snapshots to be built), and then
> > > > enable
> > > > > remote storage.
> > > > >
> > > > > 9102. RemotePartitionRemover(RPM) process: Is it true that RPM starts
> > > > > tracking the remote segments when
> > RLMM.onPartitionLeadershipChanges() is
> > > > > called with the broker being the leader for __remote_log_metadata
> > > > > partition? If so, could we document it?
> > > > >
> > > > > Jun
> > > > >
> > > > > On Tue, Dec 15, 2020 at 8:47 AM Kowshik Prakasam <
> > kprakasam@confluent.io
> > > > >
> > > > > wrote:
> > > > >
> > > > > > Hi Satish,
> > > > > >
> > > > > > Thanks for the updates! A few more comments below.
> > > > > >
> > > > > > 9001. Under the "Upgrade" section, there is a line mentioning:
> > > > "Upgrade the
> > > > > > existing Kafka cluster to 2.7 version and allow this to run for
> > the log
> > > > > > retention of user topics that you want to enable tiered storage.
> > This
> > > > will
> > > > > > allow all the topics to have the producer snapshots generated for
> > each
> > > > log
> > > > > > segment." -- Which associated change in AK were you referring to
> > here?
> > > > Is
> > > > > > it: https://github.com/apache/kafka/pull/7929 ? It seems like I
> > don't
> > > > see
> > > > > > it in the 2.7 release branch yet, here is the link:
> > > > > > https://github.com/apache/kafka/commits/2.7.
> > > > > >
> > > > > > 9002. Under the "Upgrade" section, the configuration mentioned is
> > > > > > 'remote.log.storage.system.enable'. However, under "Public
> > Interfaces"
> > > > > > section the corresponding configuration is
> > > > 'remote.storage.system.enable'.
> > > > > > Could we use the same one in both, maybe
> > > > > > 'remote.log.storage.system.enable'?
> > > > > >
> > > > > > 9003. Under "Per Topic Configuration", the KIP recommends setting
> > > > > > 'remote.log.storage.enable' to true at a per-topic level. It will
> > be
> > > > useful
> > > > > > to add a line that if the user wants to enable it for all topics,
> > then
> > > > they
> > > > > > should be able to set the cluster-wide default to true. Also, it
> > will
> > > > be
> > > > > > useful to mention that the KIP currently does not support setting
> > it to
> > > > > > false (after it is set to true), and add that to the future work
> > > > section.
> > > > > >
> > > > > > 9004. Under "Committed offsets file format", the sample provided
> > shows
> > > > > > partition number and offset. Is the topic name required for
> > identifying
> > > > > > which topic the partitions belong to?
> > > > > >
> > > > > > 9005. Under "Internal flat-file store format of remote log
> > metadata",
> > > > it
> > > > > > seems useful to specify both topic name and topic ID for debugging
> > > > > > purposes.
> > > > > >
> > > > > > 9006. Under "Internal flat-file store format of remote log
> > metadata",
> > > > the
> > > > > > description of "metadata-topic-offset" currently says "offset of
> > the
> > > > remote
> > > > > > log metadata topic from which this topic partition's remote log
> > > > metadata is
> > > > > > fetched." Just for the wording, perhaps you meant to refer to the
> > > > offset
> > > > > > upto which the file has been committed? i.e. "offset of the remote
> > log
> > > > > > metadata topic upto which this topic partition's remote log
> > metadata
> > > > has
> > > > > > been committed into this file."
> > > > > >
> > > > > > 9007. Under "Internal flat-file store format of remote log
> > metadata",
> > > > the
> > > > > > schema of the payload (i.e. beyond the header) seems to contain the
> > > > events
> > > > > > from the metadata topic. It seems useful to instead persist the
> > > > > > representation of the materialized state of the events, so that
> > for the
> > > > > > same segment only the latest state is stored. Besides reducing
> > storage
> > > > > > footprint, this also is likely to relate directly with the
> > in-memory
> > > > > > representation of the RLMM cache (which probably is some kind of a
> > Map
> > > > with
> > > > > > key being segment ID and value being the segment state), so
> > recovery
> > > > from
> > > > > > disk will be straightforward.
> > > > > >
> > > > > > 9008. Under "Topic deletion lifecycle", step (1), it will be
> > useful to
> > > > > > mention when in the deletion flow does the controller publish the
> > > > > > delete_partition_marked event to say that the partition is marked
> > for
> > > > > > deletion?
> > > > > >
> > > > > > 9009. There are ~4 TODOs in the KIP. Could you please address
> > these or
> > > > > > remove them?
> > > > > >
> > > > > > 9010. There is a reference to a Google doc on the KIP which was
> > used
> > > > > > earlier for discussions. Please could you remove the reference,
> > since
> > > > the
> > > > > > KIP is the source of the truth?
> > > > > >
> > > > > > 9011. This feedback is from an earlier comment. In the
> > > > RemoteStorageManager
> > > > > > interface, there is an API defined for each file type. For example,
> > > > > > fetchOffsetIndex, fetchTimestampIndex etc. To avoid the
> > duplication,
> > > > I'd
> > > > > > suggest we can instead have a FileType enum and a common get API
> > based
> > > > on
> > > > > > the FileType. What do you think?
> > > > > >
> > > > > >
> > > > > > Cheers,
> > > > > > Kowshik
> > > > > >
> > > > > >
> > > > > > On Mon, Dec 14, 2020 at 11:07 AM Satish Duggana <
> > > > satish.duggana@gmail.com>
> > > > > > wrote:
> > > > > >
> > > > > > > Hi Jun,
> > > > > > > Thanks for your comments. Please go through the inline replies.
> > > > > > >
> > > > > > >
> > > > > > > 5102.2: It seems that both positions can just be int. Another
> > option
> > > > is
> > > > > > to
> > > > > > > have two methods. Would it be clearer?
> > > > > > >
> > > > > > >     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> > > > > > > remoteLogSegmentMetadata,  int startPosition)
> > > > > > throwsRemoteStorageException;
> > > > > > >
> > > > > > >     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> > > > > > > remoteLogSegmentMetadata, int startPosition, int endPosition)
> > throws
> > > > > > > RemoteStorageException;
> > > > > > >
> > > > > > > That makes sense to me, updated the KIP.
> > > > > > >
> > > > > > > 6003: Could you also update the javadoc for the return value?
> > > > > > >
> > > > > > > Updated.
> > > > > > >
> > > > > > > 6020: local.log.retention.bytes: Should it default to
> > > > log.retention.bytes
> > > > > > > to be consistent with local.log.retention.ms?
> > > > > > >
> > > > > > > Yes, it can be defaulted to log.retention.bytes.
> > > > > > >
> > > > > > > 6021: Could you define TopicIdPartition?
> > > > > > >
> > > > > > > Added TopicIdPartition in the KIP.
> > > > > > >
> > > > > > > 6022: For all public facing classes, could you specify the
> > package
> > > > name?
> > > > > > >
> > > > > > > Updated.
> > > > > > >
> > > > > > >
> > > > > > > Thanks,
> > > > > > > Satish.
> > > > > > >
> > > > > > > On Tue, Dec 8, 2020 at 12:59 AM Jun Rao <ju...@confluent.io>
> > wrote:
> > > > > > > >
> > > > > > > > Hi, Satish,
> > > > > > > >
> > > > > > > > Thanks for the reply. A few more comments below.
> > > > > > > >
> > > > > > > > 5102.2: It seems that both positions can just be int. Another
> > > > option is
> > > > > > > to
> > > > > > > > have two methods. Would it be clearer?
> > > > > > > >
> > > > > > > >     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> > > > > > > > remoteLogSegmentMetadata,
> > > > > > > >                                     int startPosition) throws
> > > > > > > > RemoteStorageException;
> > > > > > > >
> > > > > > > >     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> > > > > > > > remoteLogSegmentMetadata,
> > > > > > > >                                     int startPosition, int
> > > > endPosition)
> > > > > > > > throws RemoteStorageException;
> > > > > > > >
> > > > > > > > 6003: Could you also update the javadoc for the return value?
> > > > > > > >
> > > > > > > > 6010: What kind of tiering throughput have you seen with 5
> > threads?
> > > > > > > >
> > > > > > > > 6020: local.log.retention.bytes: Should it default to
> > > > > > log.retention.bytes
> > > > > > > > to be consistent with local.log.retention.ms?
> > > > > > > >
> > > > > > > > 6021: Could you define TopicIdPartition?
> > > > > > > >
> > > > > > > > 6022: For all public facing classes, could you specify the
> > package
> > > > > > name?
> > > > > > > >
> > > > > > > > It seems that you already added the topicId support. Two other
> > > > > > remaining
> > > > > > > > items are (a) the format of local tier metadata storage and (b)
> > > > > > upgrade.
> > > > > > > >
> > > > > > > > Jun
> > > > > > > >
> > > > > > > > On Mon, Dec 7, 2020 at 8:56 AM Satish Duggana <
> > > > > > satish.duggana@gmail.com>
> > > > > > > > wrote:
> > > > > > > >
> > > > > > > > > Hi Jun,
> > > > > > > > > Thanks for your comments. Please find the inline replies
> > below.
> > > > > > > > >
> > > > > > > > > >605.2 It's rare for the follower to need the remote data.
> > So,
> > > > the
> > > > > > > current
> > > > > > > > > approach is fine too. Could you document the process of
> > > > rebuilding
> > > > > > the
> > > > > > > > > producer state since we can't simply trim the producerState
> > to an
> > > > > > > offset in
> > > > > > > > > the middle of a segment.
> > > > > > > > >
> > > > > > > > > Will clarify in the KIP.
> > > > > > > > >
> > > > > > > > > >5102.2 Would it be clearer to make startPosiont long and
> > > > endPosition
> > > > > > > of
> > > > > > > > > Optional<Long>?
> > > > > > > > >
> > > > > > > > > We will have arg checks with respective validation. It is
> > not a
> > > > good
> > > > > > > > > practice to have arguments with optional as mentioned here.
> > > > > > > > > https://rules.sonarsource.com/java/RSPEC-3553
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > >5102.5 LogSegmentData still has leaderEpochIndex as File
> > > > instead of
> > > > > > > > > ByteBuffer.
> > > > > > > > >
> > > > > > > > > Updated.
> > > > > > > > >
> > > > > > > > > >5102.7 Could you define all public methods for
> > LogSegmentData?
> > > > > > > > >
> > > > > > > > > Updated.
> > > > > > > > >
> > > > > > > > > >5103.5 Could you change the reference to
> > > > rlm_process_interval_ms and
> > > > > > > > > rlm_retry_interval_ms to the new config names? Also, the
> > retry
> > > > > > interval
> > > > > > > > > config seems still missing. It would be useful to support
> > > > exponential
> > > > > > > > > backoff with the retry interval config.
> > > > > > > > >
> > > > > > > > > Good point. We wanted the retry with truncated exponential
> > > > backoff,
> > > > > > > > > updated the KIP.
> > > > > > > > >
> > > > > > > > > >5111. "RLM follower fetches the earliest offset for the
> > earliest
> > > > > > > leader
> > > > > > > > > epoch by calling RLMM.earliestLogOffset(TopicPartition
> > > > > > topicPartition,
> > > > > > > int
> > > > > > > > > leaderEpoch) and updates that as the log start offset." This
> > > > text is
> > > > > > > still
> > > > > > > > > there. Also, could we remove earliestLogOffset() from RLMM?
> > > > > > > > >
> > > > > > > > > Updated.
> > > > > > > > >
> > > > > > > > > >5115. There are still references to "remote log cleaners".
> > > > > > > > >
> > > > > > > > > Updated.
> > > > > > > > >
> > > > > > > > > >6000. Since we are returning new error codes, we need to
> > bump
> > > > up the
> > > > > > > > > protocol version for Fetch request. Also, it will be useful
> > to
> > > > > > > document all
> > > > > > > > > new error codes and whether they are retriable or not.
> > > > > > > > >
> > > > > > > > > Sure, we will add that in the KIP.
> > > > > > > > >
> > > > > > > > > >6001. public Map<Long, Long> segmentLeaderEpochs():
> > Currently,
> > > > > > > leaderEpoch
> > > > > > > > > is int32 instead of long.
> > > > > > > > >
> > > > > > > > > Updated.
> > > > > > > > >
> > > > > > > > > >6002. Is RemoteLogSegmentMetadata.markedForDeletion() needed
> > > > given
> > > > > > > > > RemoteLogSegmentMetadata.state()?
> > > > > > > > >
> > > > > > > > > No, it is fixed.
> > > > > > > > >
> > > > > > > > > >6003. RemoteLogSegmentMetadata
> > > > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > topicPartition, long offset, int epochForOffset): Should this
> > > > return
> > > > > > > > > Optional<RemoteLogSegmentMetadata>?
> > > > > > > > >
> > > > > > > > > That makes sense, updated.
> > > > > > > > >
> > > > > > > > > >6005. RemoteLogState: It seems it's better to split it
> > between
> > > > > > > > > DeletePartitionUpdate and RemoteLogSegmentMetadataUpdate
> > since
> > > > the
> > > > > > > states
> > > > > > > > > are never shared between the two use cases.
> > > > > > > > >
> > > > > > > > > Agree with that, updated.
> > > > > > > > >
> > > > > > > > > >6006. RLMM.onPartitionLeadershipChanges(): This may be ok.
> > > > However,
> > > > > > > is it
> > > > > > > > > ture that other than the metadata topic, RLMM just needs to
> > know
> > > > > > > whether
> > > > > > > > > there is a replica assigned to this broker and doesn't need
> > to
> > > > know
> > > > > > > whether
> > > > > > > > > the replica is the leader or the follower?
> > > > > > > > >
> > > > > > > > > That may be true. If the implementation does not need that,
> > it
> > > > can
> > > > > > > > > ignore the information in the callback.
> > > > > > > > >
> > > > > > > > > >6007: "Handle expired remote segments (leader and
> > follower)":
> > > > Why is
> > > > > > > this
> > > > > > > > > needed in both the leader and the follower?
> > > > > > > > >
> > > > > > > > > Updated.
> > > > > > > > >
> > > > > > > > > >6008.       "name": "SegmentSizeInBytes",
> > > > > > > > >                 "type": "int64",
> > > > > > > > > The segment size can just be int32.
> > > > > > > > >
> > > > > > > > > Updated.
> > > > > > > > >
> > > > > > > > > >6009. For the record format in the log, it seems that we
> > need
> > > > to add
> > > > > > > > > record
> > > > > > > > > type and record version before the serialized bytes. We can
> > > > follow
> > > > > > the
> > > > > > > > > convention used in
> > > > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > >
> > > >
> > https://cwiki.apache.org/confluence/display/KAFKA/KIP-631%3A+The+Quorum-based+Kafka+Controller#KIP631:TheQuorumbasedKafkaController-RecordFormats
> > > > > > > > >
> > > > > > > > > Yes, KIP already mentions that these are serialized before
> > the
> > > > > > payload
> > > > > > > > > as below. We will mention explicitly that these two are
> > written
> > > > > > before
> > > > > > > > > the data is written.
> > > > > > > > >
> > > > > > > > > RLMM instance on broker publishes the message to the topic
> > with
> > > > key
> > > > > > as
> > > > > > > > > null and value with the below format.
> > > > > > > > >
> > > > > > > > > type      : unsigned var int, represents the value type. This
> > > > value
> > > > > > is
> > > > > > > > > 'apikey' as mentioned in the schema.
> > > > > > > > > version : unsigned var int, the 'version' number of the type
> > as
> > > > > > > > > mentioned in the schema.
> > > > > > > > > data      : record payload in kafka protocol message format.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > >6010. remote.log.manager.thread.pool.size: The default
> > value is
> > > > 10.
> > > > > > > This
> > > > > > > > > might be too high when enabling the tiered feature for the
> > first
> > > > > > time.
> > > > > > > > > Since there are lots of segments that need to be tiered
> > > > initially, a
> > > > > > > large
> > > > > > > > > number of threads could overwhelm the broker.
> > > > > > > > >
> > > > > > > > > Is the default value 5 reasonable?
> > > > > > > > >
> > > > > > > > > 6011. "The number of milli seconds to keep the local log
> > segment
> > > > > > > before it
> > > > > > > > > gets deleted. If not set, the value in
> > `log.retention.minutes` is
> > > > > > > used. If
> > > > > > > > > set to -1, no time limit is applied." We should use
> > > > log.retention.ms
> > > > > > > > > instead of log.retention.minutes.
> > > > > > > > > Nice typo catch. Updated the KIP.
> > > > > > > > >
> > > > > > > > > Thanks,
> > > > > > > > > Satish.
> > > > > > > > >
> > > > > > > > > On Thu, Dec 3, 2020 at 8:03 AM Jun Rao <ju...@confluent.io>
> > wrote:
> > > > > > > > > >
> > > > > > > > > > Hi, Satish,
> > > > > > > > > >
> > > > > > > > > > Thanks for the updated KIP. A few more comments below.
> > > > > > > > > >
> > > > > > > > > > 605.2 It's rare for the follower to need the remote data.
> > So,
> > > > the
> > > > > > > current
> > > > > > > > > > approach is fine too. Could you document the process of
> > > > rebuilding
> > > > > > > the
> > > > > > > > > > producer state since we can't simply trim the
> > producerState to
> > > > an
> > > > > > > offset
> > > > > > > > > in
> > > > > > > > > > the middle of a segment.
> > > > > > > > > >
> > > > > > > > > > 5102.2 Would it be clearer to make startPosiont long and
> > > > > > endPosition
> > > > > > > of
> > > > > > > > > > Optional<Long>?
> > > > > > > > > >
> > > > > > > > > > 5102.5 LogSegmentData still has leaderEpochIndex as File
> > > > instead of
> > > > > > > > > > ByteBuffer.
> > > > > > > > > >
> > > > > > > > > > 5102.7 Could you define all public methods for
> > LogSegmentData?
> > > > > > > > > >
> > > > > > > > > > 5103.5 Could you change the reference to
> > > > rlm_process_interval_ms
> > > > > > and
> > > > > > > > > > rlm_retry_interval_ms to the new config names? Also, the
> > retry
> > > > > > > interval
> > > > > > > > > > config seems still missing. It would be useful to support
> > > > > > exponential
> > > > > > > > > > backoff with the retry interval config.
> > > > > > > > > >
> > > > > > > > > > 5111. "RLM follower fetches the earliest offset for the
> > > > earliest
> > > > > > > leader
> > > > > > > > > > epoch by calling RLMM.earliestLogOffset(TopicPartition
> > > > > > > topicPartition,
> > > > > > > > > int
> > > > > > > > > > leaderEpoch) and updates that as the log start offset."
> > This
> > > > text
> > > > > > is
> > > > > > > > > still
> > > > > > > > > > there. Also, could we remove earliestLogOffset() from RLMM?
> > > > > > > > > >
> > > > > > > > > > 5115. There are still references to "remote log cleaners".
> > > > > > > > > >
> > > > > > > > > > 6000. Since we are returning new error codes, we need to
> > bump
> > > > up
> > > > > > the
> > > > > > > > > > protocol version for Fetch request. Also, it will be
> > useful to
> > > > > > > document
> > > > > > > > > all
> > > > > > > > > > new error codes and whether they are retriable or not.
> > > > > > > > > >
> > > > > > > > > > 6001. public Map<Long, Long> segmentLeaderEpochs():
> > Currently,
> > > > > > > > > leaderEpoch
> > > > > > > > > > is int32 instead of long.
> > > > > > > > > >
> > > > > > > > > > 6002. Is RemoteLogSegmentMetadata.markedForDeletion()
> > needed
> > > > given
> > > > > > > > > > RemoteLogSegmentMetadata.state()?
> > > > > > > > > >
> > > > > > > > > > 6003. RemoteLogSegmentMetadata
> > > > > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > > topicPartition, long offset, int epochForOffset): Should
> > this
> > > > > > return
> > > > > > > > > > Optional<RemoteLogSegmentMetadata>?
> > > > > > > > > >
> > > > > > > > > > 6004. DeletePartitionUpdate.epoch(): It would be useful to
> > > > pick a
> > > > > > > more
> > > > > > > > > > indicative name so that people understand what epoch this
> > is.
> > > > > > > > > >
> > > > > > > > > > 6005. RemoteLogState: It seems it's better to split it
> > between
> > > > > > > > > > DeletePartitionUpdate and RemoteLogSegmentMetadataUpdate
> > since
> > > > the
> > > > > > > states
> > > > > > > > > > are never shared between the two use cases.
> > > > > > > > > >
> > > > > > > > > > 6006. RLMM.onPartitionLeadershipChanges(): This may be ok.
> > > > However,
> > > > > > > is it
> > > > > > > > > > ture that other than the metadata topic, RLMM just needs to
> > > > know
> > > > > > > whether
> > > > > > > > > > there is a replica assigned to this broker and doesn't
> > need to
> > > > know
> > > > > > > > > whether
> > > > > > > > > > the replica is the leader or the follower?
> > > > > > > > > >
> > > > > > > > > > 6007: "Handle expired remote segments (leader and
> > follower)":
> > > > Why
> > > > > > is
> > > > > > > this
> > > > > > > > > > needed in both the leader and the follower?
> > > > > > > > > >
> > > > > > > > > > 6008.       "name": "SegmentSizeInBytes",
> > > > > > > > > >                 "type": "int64",
> > > > > > > > > > The segment size can just be int32.
> > > > > > > > > >
> > > > > > > > > > 6009. For the record format in the log, it seems that we
> > need
> > > > to
> > > > > > add
> > > > > > > > > record
> > > > > > > > > > type and record version before the serialized bytes. We can
> > > > follow
> > > > > > > the
> > > > > > > > > > convention used in
> > > > > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > >
> > > >
> > https://cwiki.apache.org/confluence/display/KAFKA/KIP-631%3A+The+Quorum-based+Kafka+Controller#KIP631:TheQuorumbasedKafkaController-RecordFormats
> > > > > > > > > > .
> > > > > > > > > >
> > > > > > > > > > 6010. remote.log.manager.thread.pool.size: The default
> > value
> > > > is 10.
> > > > > > > This
> > > > > > > > > > might be too high when enabling the tiered feature for the
> > > > first
> > > > > > > time.
> > > > > > > > > > Since there are lots of segments that need to be tiered
> > > > initially,
> > > > > > a
> > > > > > > > > large
> > > > > > > > > > number of threads could overwhelm the broker.
> > > > > > > > > >
> > > > > > > > > > 6011. "The number of milli seconds to keep the local log
> > > > segment
> > > > > > > before
> > > > > > > > > it
> > > > > > > > > > gets deleted. If not set, the value in
> > `log.retention.minutes`
> > > > is
> > > > > > > used.
> > > > > > > > > If
> > > > > > > > > > set to -1, no time limit is applied." We should use
> > > > > > log.retention.ms
> > > > > > > > > > instead of log.retention.minutes.
> > > > > > > > > >
> > > > > > > > > > Jun
> > > > > > > > > >
> > > > > > > > > > On Tue, Dec 1, 2020 at 2:42 AM Satish Duggana <
> > > > > > > satish.duggana@gmail.com>
> > > > > > > > > > wrote:
> > > > > > > > > >
> > > > > > > > > > > Hi,
> > > > > > > > > > > We updated the KIP with the points mentioned in the
> > earlier
> > > > mail
> > > > > > > > > > > except for KIP-516 related changes. You can go through
> > them
> > > > and
> > > > > > > let us
> > > > > > > > > > > know if you have any comments. We will update the KIP
> > with
> > > > the
> > > > > > > > > > > remaining todo items and KIP-516 related changes by end
> > of
> > > > this
> > > > > > > > > > > week(5th Dec).
> > > > > > > > > > >
> > > > > > > > > > > Thanks,
> > > > > > > > > > > Satish.
> > > > > > > > > > >
> > > > > > > > > > > On Tue, Nov 10, 2020 at 8:26 PM Satish Duggana <
> > > > > > > > > satish.duggana@gmail.com>
> > > > > > > > > > > wrote:
> > > > > > > > > > > >
> > > > > > > > > > > > Hi Jun,
> > > > > > > > > > > > Thanks for your comments. Please find the inline
> > replies
> > > > below.
> > > > > > > > > > > >
> > > > > > > > > > > > 605.2 "Build the local leader epoch cache by cutting
> > the
> > > > leader
> > > > > > > epoch
> > > > > > > > > > > > sequence received from remote storage to [LSO, ELO]." I
> > > > > > > mentioned an
> > > > > > > > > > > issue
> > > > > > > > > > > > earlier. Suppose the leader's local start offset is
> > 100.
> > > > The
> > > > > > > follower
> > > > > > > > > > > finds
> > > > > > > > > > > > a remote segment covering offset range [80, 120). The
> > > > > > > producerState
> > > > > > > > > with
> > > > > > > > > > > > this remote segment is up to offset 120. To trim the
> > > > > > > producerState to
> > > > > > > > > > > > offset 100 requires more work since one needs to
> > download
> > > > the
> > > > > > > > > previous
> > > > > > > > > > > > producerState up to offset 80 and then replay the
> > messages
> > > > from
> > > > > > > 80 to
> > > > > > > > > > > 100.
> > > > > > > > > > > > It seems that it's simpler in this case for the
> > follower
> > > > just
> > > > > > to
> > > > > > > > > take the
> > > > > > > > > > > > remote segment as it is and start fetching from offset
> > 120.
> > > > > > > > > > > >
> > > > > > > > > > > > We chose that approach to avoid any edge cases here. It
> > > > may be
> > > > > > > > > > > > possible that the remote log segment that is received
> > may
> > > > not
> > > > > > > have
> > > > > > > > > the
> > > > > > > > > > > > same leader epoch sequence from 100-120 as it contains
> > on
> > > > the
> > > > > > > > > > > > leader(this can happen due to unclean leader). It is
> > safe
> > > > to
> > > > > > > start
> > > > > > > > > > > > from what the leader returns here.Another way is to
> > find
> > > > the
> > > > > > > remote
> > > > > > > > > > > > log segment
> > > > > > > > > > > >
> > > > > > > > > > > > 5016. Just to echo what Kowshik was saying. It seems
> > that
> > > > > > > > > > > > RLMM.onPartitionLeadershipChanges() is only called on
> > the
> > > > > > > replicas
> > > > > > > > > for a
> > > > > > > > > > > > partition, not on the replicas for the
> > > > > > > __remote_log_segment_metadata
> > > > > > > > > > > > partition. It's not clear how the leader of
> > > > > > > > > __remote_log_segment_metadata
> > > > > > > > > > > > obtains the metadata for remote segments for deletion.
> > > > > > > > > > > >
> > > > > > > > > > > > RLMM will always receive the callback for the remote
> > log
> > > > > > metadata
> > > > > > > > > > > > topic partitions hosted on the local broker and these
> > will
> > > > be
> > > > > > > > > > > > subscribed. I will make this clear in the KIP.
> > > > > > > > > > > >
> > > > > > > > > > > > 5100. KIP-516 has been accepted and is being
> > implemented
> > > > now.
> > > > > > > Could
> > > > > > > > > you
> > > > > > > > > > > > update the KIP based on topicID?
> > > > > > > > > > > >
> > > > > > > > > > > > We mentioned KIP-516 and how it helps. We will update
> > this
> > > > KIP
> > > > > > > with
> > > > > > > > > > > > all the changes it brings with KIP-516.
> > > > > > > > > > > >
> > > > > > > > > > > > 5101. RLMM: It would be useful to clarify how the
> > > > following two
> > > > > > > APIs
> > > > > > > > > are
> > > > > > > > > > > > used. According to the wiki, the former is used for
> > topic
> > > > > > > deletion
> > > > > > > > > and
> > > > > > > > > > > the
> > > > > > > > > > > > latter is used for retention. It seems that retention
> > > > should
> > > > > > use
> > > > > > > the
> > > > > > > > > > > former
> > > > > > > > > > > > since remote segments without a matching epoch in the
> > > > leader
> > > > > > > > > (potentially
> > > > > > > > > > > > due to unclean leader election) also need to be garbage
> > > > > > > collected.
> > > > > > > > > The
> > > > > > > > > > > > latter seems to be used for the new leader to
> > determine the
> > > > > > last
> > > > > > > > > tiered
> > > > > > > > > > > > segment.
> > > > > > > > > > > >     default Iterator<RemoteLogSegmentMetadata>
> > > > > > > > > > > > listRemoteLogSegments(TopicPartition topicPartition)
> > > > > > > > > > > >     Iterator<RemoteLogSegmentMetadata>
> > > > > > > > > > > listRemoteLogSegments(TopicPartition
> > > > > > > > > > > > topicPartition, long leaderEpoch);
> > > > > > > > > > > >
> > > > > > > > > > > > Right,.that is what we are currently doing. We will
> > update
> > > > the
> > > > > > > > > > > > javadocs and wiki with that. Earlier, we did not want
> > to
> > > > remove
> > > > > > > the
> > > > > > > > > > > > segments which are not matched with leader epochs from
> > the
> > > > > > ladder
> > > > > > > > > > > > partition as they may be used later by a replica which
> > can
> > > > > > > become a
> > > > > > > > > > > > leader (unclean leader election) and refer those
> > segments.
> > > > But
> > > > > > > that
> > > > > > > > > > > > may leak these segments in remote storage until the
> > topic
> > > > > > > lifetime.
> > > > > > > > > We
> > > > > > > > > > > > decided to cleanup the segments with the oldest incase
> > of
> > > > size
> > > > > > > based
> > > > > > > > > > > > retention also.
> > > > > > > > > > > >
> > > > > > > > > > > > 5102. RSM:
> > > > > > > > > > > > 5102.1 For methods like fetchLogSegmentData(), it seems
> > > > that
> > > > > > > they can
> > > > > > > > > > > > use RemoteLogSegmentId instead of
> > RemoteLogSegmentMetadata.
> > > > > > > > > > > >
> > > > > > > > > > > > It will be useful to have metadata for RSM to fetch log
> > > > > > segment.
> > > > > > > It
> > > > > > > > > > > > may create location/path using id with other metadata
> > too.
> > > > > > > > > > > >
> > > > > > > > > > > > 5102.2 In fetchLogSegmentData(), should we use long
> > > > instead of
> > > > > > > Long?
> > > > > > > > > > > >
> > > > > > > > > > > > Wanted to keep endPosition as optional to read till the
> > > > end of
> > > > > > > the
> > > > > > > > > > > > segment and avoid sentinels.
> > > > > > > > > > > >
> > > > > > > > > > > > 5102.3 Why only some of the methods have default
> > > > implementation
> > > > > > > and
> > > > > > > > > > > others
> > > > > > > > > > > > Don't?
> > > > > > > > > > > >
> > > > > > > > > > > > Actually,  RSM will not have any default
> > implementations.
> > > > > > Those 3
> > > > > > > > > > > > methods were made default earlier for tests etc.
> > Updated
> > > > the
> > > > > > > wiki.
> > > > > > > > > > > >
> > > > > > > > > > > > 5102.4. Could we define RemoteLogSegmentMetadataUpdate
> > > > > > > > > > > > and DeletePartitionUpdate?
> > > > > > > > > > > >
> > > > > > > > > > > > Sure, they will be added.
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > 5102.5 LogSegmentData: It seems that it's easier to
> > pass
> > > > > > > > > > > > in leaderEpochIndex as a ByteBuffer or byte array than
> > a
> > > > file
> > > > > > > since
> > > > > > > > > it
> > > > > > > > > > > will
> > > > > > > > > > > > be generated in memory.
> > > > > > > > > > > >
> > > > > > > > > > > > Right, this is in plan.
> > > > > > > > > > > >
> > > > > > > > > > > > 5102.6 RemoteLogSegmentMetadata: It seems that it needs
> > > > both
> > > > > > > > > baseOffset
> > > > > > > > > > > and
> > > > > > > > > > > > startOffset. For example, deleteRecords() could move
> > the
> > > > > > > startOffset
> > > > > > > > > to
> > > > > > > > > > > the
> > > > > > > > > > > > middle of a segment. If we copy the full segment to
> > remote
> > > > > > > storage,
> > > > > > > > > the
> > > > > > > > > > > > baseOffset and the startOffset will be different.
> > > > > > > > > > > >
> > > > > > > > > > > > Good point. startOffset is baseOffset by default, if
> > not
> > > > set
> > > > > > > > > explicitly.
> > > > > > > > > > > >
> > > > > > > > > > > > 5102.7 Could we define all the public methods for
> > > > > > > > > > > RemoteLogSegmentMetadata
> > > > > > > > > > > > and LogSegmentData?
> > > > > > > > > > > >
> > > > > > > > > > > > Sure, updated the wiki.
> > > > > > > > > > > >
> > > > > > > > > > > > 5102.8 Could we document whether endOffset in
> > > > > > > > > RemoteLogSegmentMetadata is
> > > > > > > > > > > > inclusive/exclusive?
> > > > > > > > > > > >
> > > > > > > > > > > > It is inclusive, will update.
> > > > > > > > > > > >
> > > > > > > > > > > > 5103. configs:
> > > > > > > > > > > > 5103.1 Could we define the default value of
> > non-required
> > > > > > configs
> > > > > > > > > (e.g the
> > > > > > > > > > > > size of new thread pools)?
> > > > > > > > > > > >
> > > > > > > > > > > > Sure, that makes sense.
> > > > > > > > > > > >
> > > > > > > > > > > > 5103.2 It seems that local.log.retention.ms should
> > > > default to
> > > > > > > > > > > retention.ms,
> > > > > > > > > > > > instead of remote.log.retention.minutes. Similarly, it
> > > > seems
> > > > > > > > > > > > that local.log.retention.bytes should default to
> > > > segment.bytes.
> > > > > > > > > > > >
> > > > > > > > > > > > Right, we do not have  remote.log.retention as we
> > discussed
> > > > > > > earlier.
> > > > > > > > > > > > Thanks for catching the typo.
> > > > > > > > > > > >
> > > > > > > > > > > > 5103.3 remote.log.manager.thread.pool.size: The
> > description
> > > > > > says
> > > > > > > > > "used in
> > > > > > > > > > > > scheduling tasks to copy segments, fetch remote log
> > > > indexes and
> > > > > > > > > clean up
> > > > > > > > > > > > remote log segments". However, there is a separate
> > > > > > > > > > > > config remote.log.reader.threads for fetching remote
> > data.
> > > > It's
> > > > > > > > > weird to
> > > > > > > > > > > > fetch remote index and log in different thread pools
> > since
> > > > both
> > > > > > > are
> > > > > > > > > used
> > > > > > > > > > > > for serving fetch requests.
> > > > > > > > > > > >
> > > > > > > > > > > > Right, remote.log.manager.thread.pool is mainly used
> > for
> > > > > > > copy/cleanup
> > > > > > > > > > > > activities. Fetch path always goes through
> > > > > > > remote.log.reader.threads.
> > > > > > > > > > > >
> > > > > > > > > > > > 5103.4 remote.log.manager.task.interval.ms: Is that
> > the
> > > > amount
> > > > > > > of
> > > > > > > > > time
> > > > > > > > > > > to
> > > > > > > > > > > > back off when there is no work to do? If so, perhaps it
> > > > can be
> > > > > > > > > renamed as
> > > > > > > > > > > > backoff.ms.
> > > > > > > > > > > >
> > > > > > > > > > > > This is the delay interval for each iteration. It may
> > be
> > > > > > renamed
> > > > > > > to
> > > > > > > > > > > > remote.log.manager.task.delay.ms
> > > > > > > > > > > >
> > > > > > > > > > > > 5103.5 Are rlm_process_interval_ms and
> > > > rlm_retry_interval_ms
> > > > > > > > > configs? If
> > > > > > > > > > > > so, they need to be listed in this section.
> > > > > > > > > > > >
> > > > > > > > > > > > remote.log.manager.task.interval.ms is the process
> > > > internal,
> > > > > > > retry
> > > > > > > > > > > > interval is missing in the configs, which will be
> > updated
> > > > in
> > > > > > the
> > > > > > > KIP.
> > > > > > > > > > > >
> > > > > > > > > > > > 5104. "RLM maintains a bounded cache(possibly LRU) of
> > the
> > > > index
> > > > > > > > > files of
> > > > > > > > > > > > remote log segments to avoid multiple index fetches
> > from
> > > > the
> > > > > > > remote
> > > > > > > > > > > > storage." Is the RLM in memory or on disk? If on disk,
> > > > where is
> > > > > > > it
> > > > > > > > > > > stored?
> > > > > > > > > > > > Do we need a configuration to bound the size?
> > > > > > > > > > > >
> > > > > > > > > > > > It is stored on disk. They are stored in a directory
> > > > > > > > > > > > `remote-log-index-cache` under log dir. We plan to
> > have a
> > > > > > config
> > > > > > > for
> > > > > > > > > > > > that instead of default. We will have a configuration
> > for
> > > > that.
> > > > > > > > > > > >
> > > > > > > > > > > > 5105. The KIP uses local-log-start-offset and Earliest
> > > > Local
> > > > > > > Offset
> > > > > > > > > in
> > > > > > > > > > > > different places. It would be useful to standardize the
> > > > > > > terminology.
> > > > > > > > > > > >
> > > > > > > > > > > > Sure.
> > > > > > > > > > > >
> > > > > > > > > > > > 5106. The section on "In BuildingRemoteLogAux state".
> > It
> > > > listed
> > > > > > > two
> > > > > > > > > > > options
> > > > > > > > > > > > without saying which option is chosen.
> > > > > > > > > > > > We already mentioned in the KIP that we chose option-2.
> > > > > > > > > > > >
> > > > > > > > > > > > 5107. Follower to leader transition: It has step 2,
> > but not
> > > > > > step
> > > > > > > 1.
> > > > > > > > > > > > Step-1 is there but it is not explicitly highlighted.
> > It is
> > > > > > > previous
> > > > > > > > > > > > table to step-2.
> > > > > > > > > > > >
> > > > > > > > > > > > 5108. If a consumer fetches from the remote data and
> > the
> > > > remote
> > > > > > > > > storage
> > > > > > > > > > > is
> > > > > > > > > > > > not available, what error code is used in the fetch
> > > > response?
> > > > > > > > > > > >
> > > > > > > > > > > > Good point. We have not yet defined the error for this
> > > > case. We
> > > > > > > need
> > > > > > > > > > > > to define an error message and send the same in fetch
> > > > response.
> > > > > > > > > > > >
> > > > > > > > > > > > 5109. "ListOffsets: For timestamps >= 0, it returns the
> > > > first
> > > > > > > message
> > > > > > > > > > > > offset whose timestamp is >= to the given timestamp in
> > the
> > > > > > > request.
> > > > > > > > > That
> > > > > > > > > > > > means it checks in remote log time indexes first, after
> > > > which
> > > > > > > local
> > > > > > > > > log
> > > > > > > > > > > > time indexes are checked." Could you document which
> > method
> > > > in
> > > > > > > RLMM is
> > > > > > > > > > > used
> > > > > > > > > > > > for this?
> > > > > > > > > > > >
> > > > > > > > > > > > Okay.
> > > > > > > > > > > >
> > > > > > > > > > > > 5110. Stopreplica: "it sets all the remote log segment
> > > > metadata
> > > > > > > of
> > > > > > > > > that
> > > > > > > > > > > > partition with a delete marker and publishes them to
> > RLMM."
> > > > > > This
> > > > > > > > > seems
> > > > > > > > > > > > outdated given the new topic deletion logic.
> > > > > > > > > > > >
> > > > > > > > > > > > Will update with KIP-516 related points.
> > > > > > > > > > > >
> > > > > > > > > > > > 5111. "RLM follower fetches the earliest offset for the
> > > > > > earliest
> > > > > > > > > leader
> > > > > > > > > > > > epoch by calling RLMM.earliestLogOffset(TopicPartition
> > > > > > > > > topicPartition,
> > > > > > > > > > > int
> > > > > > > > > > > > leaderEpoch) and updates that as the log start
> > offset." Do
> > > > we
> > > > > > > need
> > > > > > > > > that
> > > > > > > > > > > > since replication propagates logStartOffset already?
> > > > > > > > > > > >
> > > > > > > > > > > > Good point. Right, existing replication protocol takes
> > > > care of
> > > > > > > > > > > > updating the followers’s log start offset received
> > from the
> > > > > > > leader.
> > > > > > > > > > > >
> > > > > > > > > > > > 5112. Is the default maxWaitMs of 500ms enough for
> > fetching
> > > > > > from
> > > > > > > > > remote
> > > > > > > > > > > > storage?
> > > > > > > > > > > >
> > > > > > > > > > > > Remote reads may fail within the current default wait
> > > > time, but
> > > > > > > > > > > > subsequent fetches would be able to serve as that data
> > is
> > > > > > stored
> > > > > > > in
> > > > > > > > > > > > the local cache. This cache is currently implemented in
> > > > RSMs.
> > > > > > > But we
> > > > > > > > > > > > plan to pull this into the remote log messaging layer
> > in
> > > > > > future.
> > > > > > > > > > > >
> > > > > > > > > > > > 5113. "Committed offsets can be stored in a local file
> > to
> > > > avoid
> > > > > > > > > reading
> > > > > > > > > > > the
> > > > > > > > > > > > messages again when a broker is restarted." Could you
> > > > describe
> > > > > > > the
> > > > > > > > > format
> > > > > > > > > > > > and the location of the file? Also, could the same
> > message
> > > > be
> > > > > > > > > processed
> > > > > > > > > > > by
> > > > > > > > > > > > RLMM again after broker restart? If so, how do we
> > handle
> > > > that?
> > > > > > > > > > > >
> > > > > > > > > > > > Sure, we will update in the KIP.
> > > > > > > > > > > >
> > > > > > > > > > > > 5114. Message format
> > > > > > > > > > > > 5114.1 There are two records named
> > > > > > RemoteLogSegmentMetadataRecord
> > > > > > > > > with
> > > > > > > > > > > > apiKey 0 and 1.
> > > > > > > > > > > >
> > > > > > > > > > > > Nice catch, that was a typo. Fixed in the wiki.
> > > > > > > > > > > >
> > > > > > > > > > > > 5114.2 RemoteLogSegmentMetadataRecord: Could we
> > document
> > > > > > whether
> > > > > > > > > > > endOffset
> > > > > > > > > > > > is inclusive/exclusive?
> > > > > > > > > > > > It is inclusive, will update.
> > > > > > > > > > > >
> > > > > > > > > > > > 5114.3 RemoteLogSegmentMetadataRecord: Could you
> > explain
> > > > > > > LeaderEpoch
> > > > > > > > > a
> > > > > > > > > > > bit
> > > > > > > > > > > > more? Is that the epoch of the leader when it copies
> > the
> > > > > > segment
> > > > > > > to
> > > > > > > > > > > remote
> > > > > > > > > > > > storage? Also, how will this field be used?
> > > > > > > > > > > >
> > > > > > > > > > > > Right, this is the leader epoch of the broker which
> > copied
> > > > this
> > > > > > > > > > > > segment. This is helpful in reason about which broker
> > > > copied
> > > > > > the
> > > > > > > > > > > > segment to remote storage.
> > > > > > > > > > > >
> > > > > > > > > > > > 5114.4 EventTimestamp: Could you explain this a bit
> > more?
> > > > Each
> > > > > > > > > record in
> > > > > > > > > > > > Kafka already has a timestamp field. Could we just use
> > > > that?
> > > > > > > > > > > >
> > > > > > > > > > > > This is the  timestamp at which  the respective event
> > > > occurred.
> > > > > > > Added
> > > > > > > > > > > > this  to RemoteLogSegmentMetadata as RLMM can be  any
> > other
> > > > > > > > > > > > implementation. We thought about that but it looked
> > > > cleaner to
> > > > > > > use at
> > > > > > > > > > > > the message structure level instead of getting that
> > from
> > > > the
> > > > > > > consumer
> > > > > > > > > > > > record and using that to build the respective event.
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > 5114.5 SegmentSizeInBytes: Could this just be int32?
> > > > > > > > > > > >
> > > > > > > > > > > > Right, it looks like config allows only int value >=
> > 14.
> > > > > > > > > > > >
> > > > > > > > > > > > 5115. RemoteLogCleaner(RLC): This could be confused
> > with
> > > > the
> > > > > > log
> > > > > > > > > cleaner
> > > > > > > > > > > > for compaction. Perhaps it can be renamed to sth like
> > > > > > > > > > > > RemotePartitionRemover.
> > > > > > > > > > > >
> > > > > > > > > > > > I am fine with RemotePartitionRemover or
> > > > > > > RemoteLogDeletionManager(we
> > > > > > > > > > > > have other manager classes like RLM, RLMM).
> > > > > > > > > > > >
> > > > > > > > > > > > 5116. "RLC receives the delete_partition_marked and
> > > > processes
> > > > > > it
> > > > > > > if
> > > > > > > > > it is
> > > > > > > > > > > > not yet processed earlier." How does it know whether
> > > > > > > > > > > > delete_partition_marked has been processed earlier?
> > > > > > > > > > > >
> > > > > > > > > > > > This is to handle duplicate delete_partition_marked
> > > > events. RLC
> > > > > > > > > > > > internally maintains a state for the delete_partition
> > > > events
> > > > > > and
> > > > > > > if
> > > > > > > > > it
> > > > > > > > > > > > already has an existing event then it ignores if it is
> > > > already
> > > > > > > being
> > > > > > > > > > > > processed.
> > > > > > > > > > > >
> > > > > > > > > > > > 5117. Should we add a new MessageFormatter to read the
> > tier
> > > > > > > metadata
> > > > > > > > > > > topic?
> > > > > > > > > > > >
> > > > > > > > > > > > Right, this is in plan but did not mention it in the
> > KIP.
> > > > This
> > > > > > > will
> > > > > > > > > be
> > > > > > > > > > > > useful for debugging purposes too.
> > > > > > > > > > > >
> > > > > > > > > > > > 5118. "Maximum remote log reader thread pool task queue
> > > > size.
> > > > > > If
> > > > > > > the
> > > > > > > > > task
> > > > > > > > > > > > queue is full, broker will stop reading remote log
> > > > segments."
> > > > > > > What
> > > > > > > > > do we
> > > > > > > > > > > > return to the fetch request in this case?
> > > > > > > > > > > >
> > > > > > > > > > > > We return an error response for that partition.
> > > > > > > > > > > >
> > > > > > > > > > > > 5119. It would be useful to list all things not
> > supported
> > > > in
> > > > > > the
> > > > > > > > > first
> > > > > > > > > > > > version in a Future work or Limitations section. For
> > > > example,
> > > > > > > > > compacted
> > > > > > > > > > > > topic, JBOD, changing remote.log.storage.enable from
> > true
> > > > to
> > > > > > > false,
> > > > > > > > > etc.
> > > > > > > > > > > >
> > > > > > > > > > > > We already have a non-goals section which is filled
> > with
> > > > some
> > > > > > of
> > > > > > > > > these
> > > > > > > > > > > > details. Do we need another limitations section?
> > > > > > > > > > > >
> > > > > > > > > > > > Thanks,
> > > > > > > > > > > > Satish.
> > > > > > > > > > > >
> > > > > > > > > > > > On Wed, Nov 4, 2020 at 11:27 PM Jun Rao <
> > jun@confluent.io>
> > > > > > > wrote:
> > > > > > > > > > > > >
> > > > > > > > > > > > > Hi, Satish,
> > > > > > > > > > > > >
> > > > > > > > > > > > > Thanks for the updated KIP. A few more comments
> > below.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 605.2 "Build the local leader epoch cache by cutting
> > the
> > > > > > leader
> > > > > > > > > epoch
> > > > > > > > > > > > > sequence received from remote storage to [LSO,
> > ELO]." I
> > > > > > > mentioned
> > > > > > > > > an
> > > > > > > > > > > issue
> > > > > > > > > > > > > earlier. Suppose the leader's local start offset is
> > 100.
> > > > The
> > > > > > > > > follower
> > > > > > > > > > > finds
> > > > > > > > > > > > > a remote segment covering offset range [80, 120). The
> > > > > > > producerState
> > > > > > > > > > > with
> > > > > > > > > > > > > this remote segment is up to offset 120. To trim the
> > > > > > > producerState
> > > > > > > > > to
> > > > > > > > > > > > > offset 100 requires more work since one needs to
> > > > download the
> > > > > > > > > previous
> > > > > > > > > > > > > producerState up to offset 80 and then replay the
> > > > messages
> > > > > > > from 80
> > > > > > > > > to
> > > > > > > > > > > 100.
> > > > > > > > > > > > > It seems that it's simpler in this case for the
> > follower
> > > > just
> > > > > > > to
> > > > > > > > > take
> > > > > > > > > > > the
> > > > > > > > > > > > > remote segment as it is and start fetching from
> > offset
> > > > 120.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5016. Just to echo what Kowshik was saying. It seems
> > that
> > > > > > > > > > > > > RLMM.onPartitionLeadershipChanges() is only called
> > on the
> > > > > > > replicas
> > > > > > > > > for
> > > > > > > > > > > a
> > > > > > > > > > > > > partition, not on the replicas for the
> > > > > > > > > __remote_log_segment_metadata
> > > > > > > > > > > > > partition. It's not clear how the leader of
> > > > > > > > > > > __remote_log_segment_metadata
> > > > > > > > > > > > > obtains the metadata for remote segments for
> > deletion.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5100. KIP-516 has been accepted and is being
> > implemented
> > > > now.
> > > > > > > > > Could you
> > > > > > > > > > > > > update the KIP based on topicID?
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5101. RLMM: It would be useful to clarify how the
> > > > following
> > > > > > two
> > > > > > > > > APIs
> > > > > > > > > > > are
> > > > > > > > > > > > > used. According to the wiki, the former is used for
> > topic
> > > > > > > deletion
> > > > > > > > > and
> > > > > > > > > > > the
> > > > > > > > > > > > > latter is used for retention. It seems that retention
> > > > should
> > > > > > > use
> > > > > > > > > the
> > > > > > > > > > > former
> > > > > > > > > > > > > since remote segments without a matching epoch in the
> > > > leader
> > > > > > > > > > > (potentially
> > > > > > > > > > > > > due to unclean leader election) also need to be
> > garbage
> > > > > > > collected.
> > > > > > > > > The
> > > > > > > > > > > > > latter seems to be used for the new leader to
> > determine
> > > > the
> > > > > > > last
> > > > > > > > > tiered
> > > > > > > > > > > > > segment.
> > > > > > > > > > > > >     default Iterator<RemoteLogSegmentMetadata>
> > > > > > > > > > > > > listRemoteLogSegments(TopicPartition topicPartition)
> > > > > > > > > > > > >     Iterator<RemoteLogSegmentMetadata>
> > > > > > > > > > > listRemoteLogSegments(TopicPartition
> > > > > > > > > > > > > topicPartition, long leaderEpoch);
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5102. RSM:
> > > > > > > > > > > > > 5102.1 For methods like fetchLogSegmentData(), it
> > seems
> > > > that
> > > > > > > they
> > > > > > > > > can
> > > > > > > > > > > > > use RemoteLogSegmentId instead of
> > > > RemoteLogSegmentMetadata.
> > > > > > > > > > > > > 5102.2 In fetchLogSegmentData(), should we use long
> > > > instead
> > > > > > of
> > > > > > > > > Long?
> > > > > > > > > > > > > 5102.3 Why only some of the methods have default
> > > > > > > implementation and
> > > > > > > > > > > others
> > > > > > > > > > > > > don't?
> > > > > > > > > > > > > 5102.4. Could we define
> > RemoteLogSegmentMetadataUpdate
> > > > > > > > > > > > > and DeletePartitionUpdate?
> > > > > > > > > > > > > 5102.5 LogSegmentData: It seems that it's easier to
> > pass
> > > > > > > > > > > > > in leaderEpochIndex as a ByteBuffer or byte array
> > than a
> > > > file
> > > > > > > > > since it
> > > > > > > > > > > will
> > > > > > > > > > > > > be generated in memory.
> > > > > > > > > > > > > 5102.6 RemoteLogSegmentMetadata: It seems that it
> > needs
> > > > both
> > > > > > > > > > > baseOffset and
> > > > > > > > > > > > > startOffset. For example, deleteRecords() could move
> > the
> > > > > > > > > startOffset
> > > > > > > > > > > to the
> > > > > > > > > > > > > middle of a segment. If we copy the full segment to
> > > > remote
> > > > > > > > > storage, the
> > > > > > > > > > > > > baseOffset and the startOffset will be different.
> > > > > > > > > > > > > 5102.7 Could we define all the public methods for
> > > > > > > > > > > RemoteLogSegmentMetadata
> > > > > > > > > > > > > and LogSegmentData?
> > > > > > > > > > > > > 5102.8 Could we document whether endOffset in
> > > > > > > > > RemoteLogSegmentMetadata
> > > > > > > > > > > is
> > > > > > > > > > > > > inclusive/exclusive?
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5103. configs:
> > > > > > > > > > > > > 5103.1 Could we define the default value of
> > non-required
> > > > > > > configs
> > > > > > > > > (e.g
> > > > > > > > > > > the
> > > > > > > > > > > > > size of new thread pools)?
> > > > > > > > > > > > > 5103.2 It seems that local.log.retention.ms should
> > > > default
> > > > > > to
> > > > > > > > > > > retention.ms,
> > > > > > > > > > > > > instead of remote.log.retention.minutes. Similarly,
> > it
> > > > seems
> > > > > > > > > > > > > that local.log.retention.bytes should default to
> > > > > > segment.bytes.
> > > > > > > > > > > > > 5103.3 remote.log.manager.thread.pool.size: The
> > > > description
> > > > > > > says
> > > > > > > > > "used
> > > > > > > > > > > in
> > > > > > > > > > > > > scheduling tasks to copy segments, fetch remote log
> > > > indexes
> > > > > > and
> > > > > > > > > clean
> > > > > > > > > > > up
> > > > > > > > > > > > > remote log segments". However, there is a separate
> > > > > > > > > > > > > config remote.log.reader.threads for fetching remote
> > > > data.
> > > > > > It's
> > > > > > > > > weird
> > > > > > > > > > > to
> > > > > > > > > > > > > fetch remote index and log in different thread pools
> > > > since
> > > > > > > both are
> > > > > > > > > > > used
> > > > > > > > > > > > > for serving fetch requests.
> > > > > > > > > > > > > 5103.4 remote.log.manager.task.interval.ms: Is that
> > the
> > > > > > > amount of
> > > > > > > > > > > time to
> > > > > > > > > > > > > back off when there is no work to do? If so, perhaps
> > it
> > > > can
> > > > > > be
> > > > > > > > > renamed
> > > > > > > > > > > as
> > > > > > > > > > > > > backoff.ms.
> > > > > > > > > > > > > 5103.5 Are rlm_process_interval_ms and
> > > > rlm_retry_interval_ms
> > > > > > > > > configs?
> > > > > > > > > > > If
> > > > > > > > > > > > > so, they need to be listed in this section.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5104. "RLM maintains a bounded cache(possibly LRU)
> > of the
> > > > > > index
> > > > > > > > > files
> > > > > > > > > > > of
> > > > > > > > > > > > > remote log segments to avoid multiple index fetches
> > from
> > > > the
> > > > > > > remote
> > > > > > > > > > > > > storage." Is the RLM in memory or on disk? If on
> > disk,
> > > > where
> > > > > > > is it
> > > > > > > > > > > stored?
> > > > > > > > > > > > > Do we need a configuration to bound the size?
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5105. The KIP uses local-log-start-offset and
> > Earliest
> > > > Local
> > > > > > > > > Offset in
> > > > > > > > > > > > > different places. It would be useful to standardize
> > the
> > > > > > > > > terminology.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5106. The section on "In BuildingRemoteLogAux
> > state". It
> > > > > > > listed two
> > > > > > > > > > > options
> > > > > > > > > > > > > without saying which option is chosen.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5107. Follower to leader transition: It has step 2,
> > but
> > > > not
> > > > > > > step 1.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5108. If a consumer fetches from the remote data and
> > the
> > > > > > remote
> > > > > > > > > > > storage is
> > > > > > > > > > > > > not available, what error code is used in the fetch
> > > > response?
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5109. "ListOffsets: For timestamps >= 0, it returns
> > the
> > > > first
> > > > > > > > > message
> > > > > > > > > > > > > offset whose timestamp is >= to the given timestamp
> > in
> > > > the
> > > > > > > request.
> > > > > > > > > > > That
> > > > > > > > > > > > > means it checks in remote log time indexes first,
> > after
> > > > which
> > > > > > > > > local log
> > > > > > > > > > > > > time indexes are checked." Could you document which
> > > > method in
> > > > > > > RLMM
> > > > > > > > > is
> > > > > > > > > > > used
> > > > > > > > > > > > > for this?
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5110. Stopreplica: "it sets all the remote log
> > segment
> > > > > > > metadata of
> > > > > > > > > that
> > > > > > > > > > > > > partition with a delete marker and publishes them to
> > > > RLMM."
> > > > > > > This
> > > > > > > > > seems
> > > > > > > > > > > > > outdated given the new topic deletion logic.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5111. "RLM follower fetches the earliest offset for
> > the
> > > > > > > earliest
> > > > > > > > > leader
> > > > > > > > > > > > > epoch by calling
> > RLMM.earliestLogOffset(TopicPartition
> > > > > > > > > topicPartition,
> > > > > > > > > > > int
> > > > > > > > > > > > > leaderEpoch) and updates that as the log start
> > offset."
> > > > Do we
> > > > > > > need
> > > > > > > > > that
> > > > > > > > > > > > > since replication propagates logStartOffset already?
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5112. Is the default maxWaitMs of 500ms enough for
> > > > fetching
> > > > > > > from
> > > > > > > > > remote
> > > > > > > > > > > > > storage?
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5113. "Committed offsets can be stored in a local
> > file to
> > > > > > avoid
> > > > > > > > > > > reading the
> > > > > > > > > > > > > messages again when a broker is restarted." Could you
> > > > > > describe
> > > > > > > the
> > > > > > > > > > > format
> > > > > > > > > > > > > and the location of the file? Also, could the same
> > > > message be
> > > > > > > > > > > processed by
> > > > > > > > > > > > > RLMM again after broker restart? If so, how do we
> > handle
> > > > > > that?
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5114. Message format
> > > > > > > > > > > > > 5114.1 There are two records named
> > > > > > > RemoteLogSegmentMetadataRecord
> > > > > > > > > with
> > > > > > > > > > > > > apiKey 0 and 1.
> > > > > > > > > > > > > 5114.2 RemoteLogSegmentMetadataRecord: Could we
> > document
> > > > > > > whether
> > > > > > > > > > > endOffset
> > > > > > > > > > > > > is inclusive/exclusive?
> > > > > > > > > > > > > 5114.3 RemoteLogSegmentMetadataRecord: Could you
> > explain
> > > > > > > > > LeaderEpoch a
> > > > > > > > > > > bit
> > > > > > > > > > > > > more? Is that the epoch of the leader when it copies
> > the
> > > > > > > segment to
> > > > > > > > > > > remote
> > > > > > > > > > > > > storage? Also, how will this field be used?
> > > > > > > > > > > > > 5114.4 EventTimestamp: Could you explain this a bit
> > more?
> > > > > > Each
> > > > > > > > > record
> > > > > > > > > > > in
> > > > > > > > > > > > > Kafka already has a timestamp field. Could we just
> > use
> > > > that?
> > > > > > > > > > > > > 5114.5 SegmentSizeInBytes: Could this just be int32?
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5115. RemoteLogCleaner(RLC): This could be confused
> > with
> > > > the
> > > > > > > log
> > > > > > > > > > > cleaner
> > > > > > > > > > > > > for compaction. Perhaps it can be renamed to sth like
> > > > > > > > > > > > > RemotePartitionRemover.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5116. "RLC receives the delete_partition_marked and
> > > > processes
> > > > > > > it
> > > > > > > > > if it
> > > > > > > > > > > is
> > > > > > > > > > > > > not yet processed earlier." How does it know whether
> > > > > > > > > > > > > delete_partition_marked has been processed earlier?
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5117. Should we add a new MessageFormatter to read
> > the
> > > > tier
> > > > > > > > > metadata
> > > > > > > > > > > topic?
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5118. "Maximum remote log reader thread pool task
> > queue
> > > > size.
> > > > > > > If
> > > > > > > > > the
> > > > > > > > > > > task
> > > > > > > > > > > > > queue is full, broker will stop reading remote log
> > > > segments."
> > > > > > > What
> > > > > > > > > do
> > > > > > > > > > > we
> > > > > > > > > > > > > return to the fetch request in this case?
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5119. It would be useful to list all things not
> > > > supported in
> > > > > > > the
> > > > > > > > > first
> > > > > > > > > > > > > version in a Future work or Limitations section. For
> > > > example,
> > > > > > > > > compacted
> > > > > > > > > > > > > topic, JBOD, changing remote.log.storage.enable from
> > > > true to
> > > > > > > false,
> > > > > > > > > > > etc.
> > > > > > > > > > > > >
> > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > >
> > > > > > > > > > > > > Jun
> > > > > > > > > > > > >
> > > > > > > > > > > > > On Tue, Oct 27, 2020 at 5:57 PM Kowshik Prakasam <
> > > > > > > > > > > kprakasam@confluent.io>
> > > > > > > > > > > > > wrote:
> > > > > > > > > > > > >
> > > > > > > > > > > > > > Hi Satish,
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Thanks for the updates to the KIP. Here are my
> > first
> > > > batch
> > > > > > of
> > > > > > > > > > > > > > comments/suggestions on the latest version of the
> > KIP.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5012. In the RemoteStorageManager interface, there
> > is
> > > > an
> > > > > > API
> > > > > > > > > defined
> > > > > > > > > > > for
> > > > > > > > > > > > > > each file type. For example, fetchOffsetIndex,
> > > > > > > > > fetchTimestampIndex
> > > > > > > > > > > etc. To
> > > > > > > > > > > > > > avoid the duplication, I'd suggest we can instead
> > have
> > > > a
> > > > > > > FileType
> > > > > > > > > > > enum and
> > > > > > > > > > > > > > a common get API based on the FileType.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5013. There are some references to the Google doc
> > in
> > > > the
> > > > > > > KIP. I
> > > > > > > > > > > wasn't sure
> > > > > > > > > > > > > > if the Google doc is expected to be in sync with
> > the
> > > > > > > contents of
> > > > > > > > > the
> > > > > > > > > > > wiki.
> > > > > > > > > > > > > > Going forward, it seems easier if just the KIP is
> > > > > > maintained
> > > > > > > as
> > > > > > > > > the
> > > > > > > > > > > source
> > > > > > > > > > > > > > of truth. In this regard, could you please move
> > all the
> > > > > > > > > references
> > > > > > > > > > > to the
> > > > > > > > > > > > > > Google doc, maybe to a separate References section
> > at
> > > > the
> > > > > > > bottom
> > > > > > > > > of
> > > > > > > > > > > the
> > > > > > > > > > > > > > KIP?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5014. There are some TODO sections in the KIP.
> > Would
> > > > these
> > > > > > be
> > > > > > > > > filled
> > > > > > > > > > > up in
> > > > > > > > > > > > > > future iterations?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5015. Under "Topic deletion lifecycle", I'm trying
> > to
> > > > > > > understand
> > > > > > > > > why
> > > > > > > > > > > do we
> > > > > > > > > > > > > > need delete_partition_marked as well as the
> > > > > > > > > delete_partition_started
> > > > > > > > > > > > > > messages. I couldn't spot a drawback if supposing
> > we
> > > > > > > simplified
> > > > > > > > > the
> > > > > > > > > > > design
> > > > > > > > > > > > > > such that the controller would only write
> > > > > > > > > delete_partition_started
> > > > > > > > > > > message,
> > > > > > > > > > > > > > and RemoteLogCleaner (RLC) instance picks it up for
> > > > > > > processing.
> > > > > > > > > What
> > > > > > > > > > > am I
> > > > > > > > > > > > > > missing?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5016. Under "Topic deletion lifecycle", step (4) is
> > > > > > > mentioned as
> > > > > > > > > > > "RLC gets
> > > > > > > > > > > > > > all the remote log segments for the partition and
> > each
> > > > of
> > > > > > > these
> > > > > > > > > > > remote log
> > > > > > > > > > > > > > segments is deleted with the next steps.". Since
> > the
> > > > RLC
> > > > > > > instance
> > > > > > > > > > > runs on
> > > > > > > > > > > > > > each tier topic partition leader, how does the RLC
> > > > then get
> > > > > > > the
> > > > > > > > > list
> > > > > > > > > > > of
> > > > > > > > > > > > > > remote log segments to be deleted? It will be
> > useful
> > > > to add
> > > > > > > that
> > > > > > > > > > > detail to
> > > > > > > > > > > > > > the KIP.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5017. Under "Public Interfaces -> Configs", there
> > is a
> > > > line
> > > > > > > > > > > mentioning "We
> > > > > > > > > > > > > > will support flipping remote.log.storage.enable in
> > next
> > > > > > > > > versions."
> > > > > > > > > > > It will
> > > > > > > > > > > > > > be useful to mention this in the "Future Work"
> > section
> > > > of
> > > > > > > the KIP
> > > > > > > > > > > too.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5018. The KIP introduces a number of configuration
> > > > > > > parameters. It
> > > > > > > > > > > will be
> > > > > > > > > > > > > > useful to mention in the KIP if the user should
> > assume
> > > > > > these
> > > > > > > as
> > > > > > > > > > > static
> > > > > > > > > > > > > > configuration in the server.properties file, or
> > dynamic
> > > > > > > > > > > configuration which
> > > > > > > > > > > > > > can be modified without restarting the broker.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5019.  Maybe this is planned as a future update to
> > the
> > > > KIP,
> > > > > > > but I
> > > > > > > > > > > thought
> > > > > > > > > > > > > > I'd mention it here. Could you please add details
> > to
> > > > the
> > > > > > KIP
> > > > > > > on
> > > > > > > > > why
> > > > > > > > > > > RocksDB
> > > > > > > > > > > > > > was chosen as the default cache implementation of
> > > > RLMM, and
> > > > > > > how
> > > > > > > > > it
> > > > > > > > > > > is going
> > > > > > > > > > > > > > to be used? Were alternatives compared/considered?
> > For
> > > > > > > example,
> > > > > > > > > it
> > > > > > > > > > > would be
> > > > > > > > > > > > > > useful to explain/evaluate the following: 1)
> > > > debuggability
> > > > > > > of the
> > > > > > > > > > > RocksDB
> > > > > > > > > > > > > > JNI interface, 2) performance, 3) portability
> > across
> > > > > > > platforms
> > > > > > > > > and 4)
> > > > > > > > > > > > > > interface parity of RocksDB’s JNI api with it's
> > > > underlying
> > > > > > > C/C++
> > > > > > > > > api.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5020. Following up on (5019), for the RocksDB
> > cache, it
> > > > > > will
> > > > > > > be
> > > > > > > > > > > useful to
> > > > > > > > > > > > > > explain the relationship/mapping between the
> > following
> > > > in
> > > > > > the
> > > > > > > > > KIP:
> > > > > > > > > > > 1) # of
> > > > > > > > > > > > > > tiered partitions, 2) # of partitions of metadata
> > topic
> > > > > > > > > > > > > > __remote_log_metadata and 3) # of RocksDB
> > instances.
> > > > i.e.
> > > > > > is
> > > > > > > the
> > > > > > > > > > > plan to
> > > > > > > > > > > > > > have a RocksDB instance per tiered partition, or
> > per
> > > > > > metadata
> > > > > > > > > topic
> > > > > > > > > > > > > > partition, or just 1 for per broker?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5021. I was looking at the implementation
> > prototype (PR
> > > > > > link:
> > > > > > > > > > > > > > https://github.com/apache/kafka/pull/7561). It
> > seems
> > > > that
> > > > > > a
> > > > > > > > > boolean
> > > > > > > > > > > > > > attribute is being introduced into the Log layer to
> > > > check
> > > > > > if
> > > > > > > > > remote
> > > > > > > > > > > log
> > > > > > > > > > > > > > capability is enabled. While the boolean footprint
> > is
> > > > small
> > > > > > > at
> > > > > > > > > the
> > > > > > > > > > > moment,
> > > > > > > > > > > > > > this can easily grow in the future and become
> > harder to
> > > > > > > > > > > > > > test/maintain, considering that the Log layer is
> > > > already
> > > > > > > pretty
> > > > > > > > > > > complex. We
> > > > > > > > > > > > > > should start thinking about how to manage such
> > changes
> > > > to
> > > > > > > the Log
> > > > > > > > > > > layer
> > > > > > > > > > > > > > (for the purpose of improved testability, better
> > > > separation
> > > > > > > of
> > > > > > > > > > > concerns and
> > > > > > > > > > > > > > readability). One proposal I have is to take a step
> > > > back
> > > > > > and
> > > > > > > > > define a
> > > > > > > > > > > > > > higher level Log interface. Then, the Broker code
> > can
> > > > be
> > > > > > > changed
> > > > > > > > > to
> > > > > > > > > > > use
> > > > > > > > > > > > > > this interface. It can be changed such that only a
> > > > handle
> > > > > > to
> > > > > > > the
> > > > > > > > > > > interface
> > > > > > > > > > > > > > is exposed to other components (such as LogCleaner,
> > > > > > > > > ReplicaManager
> > > > > > > > > > > etc.)
> > > > > > > > > > > > > > and not the underlying Log object. This approach
> > keeps
> > > > the
> > > > > > > user
> > > > > > > > > of
> > > > > > > > > > > the Log
> > > > > > > > > > > > > > layer agnostic of the whereabouts of the data.
> > > > Underneath
> > > > > > the
> > > > > > > > > > > interface,
> > > > > > > > > > > > > > the implementing classes can completely separate
> > local
> > > > log
> > > > > > > > > > > capabilities
> > > > > > > > > > > > > > from the remote log. For example, the Log class
> > can be
> > > > > > > > > simplified to
> > > > > > > > > > > only
> > > > > > > > > > > > > > manage logic surrounding local log segments and
> > > > metadata.
> > > > > > > > > > > Additionally, a
> > > > > > > > > > > > > > wrapper class can be provided (implementing the
> > higher
> > > > > > level
> > > > > > > Log
> > > > > > > > > > > interface)
> > > > > > > > > > > > > > which will contain any/all logic surrounding tiered
> > > > data.
> > > > > > The
> > > > > > > > > wrapper
> > > > > > > > > > > > > > class will wrap around an instance of the Log class
> > > > > > > delegating
> > > > > > > > > the
> > > > > > > > > > > local
> > > > > > > > > > > > > > log logic to it. Finally, a handle to the wrapper
> > > > class can
> > > > > > > be
> > > > > > > > > > > exposed to
> > > > > > > > > > > > > > the other components wherever they need a handle
> > to the
> > > > > > > higher
> > > > > > > > > level
> > > > > > > > > > > Log
> > > > > > > > > > > > > > interface.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Cheers,
> > > > > > > > > > > > > > Kowshik
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > On Mon, Oct 26, 2020 at 9:52 PM Satish Duggana <
> > > > > > > > > > > satish.duggana@gmail.com>
> > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Hi,
> > > > > > > > > > > > > > > KIP is updated with 1) topic deletion lifecycle
> > and
> > > > its
> > > > > > > related
> > > > > > > > > > > items
> > > > > > > > > > > > > > > 2) Protocol changes(mainly related to
> > ListOffsets)
> > > > and
> > > > > > > other
> > > > > > > > > minor
> > > > > > > > > > > > > > > changes.
> > > > > > > > > > > > > > > Please go through them and let us know your
> > comments.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > Satish.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > On Mon, Sep 28, 2020 at 9:10 PM Satish Duggana <
> > > > > > > > > > > satish.duggana@gmail.com
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Hi Dhruvil,
> > > > > > > > > > > > > > > > Thanks for looking into the KIP and sending
> > your
> > > > > > > comments.
> > > > > > > > > Sorry
> > > > > > > > > > > for
> > > > > > > > > > > > > > > > the late reply, missed it in the mail thread.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 1. Could you describe how retention would work
> > with
> > > > > > this
> > > > > > > KIP
> > > > > > > > > and
> > > > > > > > > > > which
> > > > > > > > > > > > > > > > threads are responsible for driving this work?
> > I
> > > > > > believe
> > > > > > > > > there
> > > > > > > > > > > are 3
> > > > > > > > > > > > > > > kinds
> > > > > > > > > > > > > > > > of retention processes we are looking at:
> > > > > > > > > > > > > > > >   (a) Regular retention for data in tiered
> > storage
> > > > as
> > > > > > per
> > > > > > > > > > > configured `
> > > > > > > > > > > > > > > > retention.ms` / `retention.bytes`.
> > > > > > > > > > > > > > > >   (b) Local retention for data in local
> > storage as
> > > > per
> > > > > > > > > > > configured `
> > > > > > > > > > > > > > > > local.log.retention.ms` /
> > > > `local.log.retention.bytes`
> > > > > > > > > > > > > > > >   (c) Possibly regular retention for data in
> > local
> > > > > > > storage,
> > > > > > > > > if
> > > > > > > > > > > the
> > > > > > > > > > > > > > > tiering
> > > > > > > > > > > > > > > > task is lagging or for data that is below the
> > log
> > > > start
> > > > > > > > > offset.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Local log retention is done by the existing log
> > > > cleanup
> > > > > > > > > tasks.
> > > > > > > > > > > These
> > > > > > > > > > > > > > > > are not done for segments that are not yet
> > copied
> > > > to
> > > > > > > remote
> > > > > > > > > > > storage.
> > > > > > > > > > > > > > > > Remote log cleanup is done by the leader
> > > > partition’s
> > > > > > > RLMTask.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 2. When does a segment become eligible to be
> > > > tiered? Is
> > > > > > > it as
> > > > > > > > > > > soon as
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > segment is rolled and the end offset is less
> > than
> > > > the
> > > > > > > last
> > > > > > > > > stable
> > > > > > > > > > > > > > offset
> > > > > > > > > > > > > > > as
> > > > > > > > > > > > > > > > mentioned in the KIP? I wonder if we need to
> > > > consider
> > > > > > > other
> > > > > > > > > > > parameters
> > > > > > > > > > > > > > > too,
> > > > > > > > > > > > > > > > like the highwatermark so that we are
> > guaranteed
> > > > that
> > > > > > > what
> > > > > > > > > we are
> > > > > > > > > > > > > > tiering
> > > > > > > > > > > > > > > > has been committed to the log and accepted by
> > the
> > > > ISR.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > AFAIK, last stable offset is always <=
> > > > highwatermark.
> > > > > > > This
> > > > > > > > > will
> > > > > > > > > > > make
> > > > > > > > > > > > > > > > sure we are always tiering the message segments
> > > > which
> > > > > > > have
> > > > > > > > > been
> > > > > > > > > > > > > > > > accepted by ISR and transactionally completed.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 3. The section on "Follower Fetch Scenarios" is
> > > > useful
> > > > > > > but
> > > > > > > > > is a
> > > > > > > > > > > bit
> > > > > > > > > > > > > > > > difficult to parse at the moment. It would be
> > > > useful to
> > > > > > > > > > > summarize the
> > > > > > > > > > > > > > > > changes we need in the ReplicaFetcher.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > It may become difficult for users to
> > read/follow
> > > > if we
> > > > > > > add
> > > > > > > > > code
> > > > > > > > > > > changes
> > > > > > > > > > > > > > > here.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 4. Related to the above, it's a bit unclear
> > how we
> > > > are
> > > > > > > > > planning
> > > > > > > > > > > on
> > > > > > > > > > > > > > > > restoring the producer state for a new replica.
> > > > Could
> > > > > > you
> > > > > > > > > expand
> > > > > > > > > > > on
> > > > > > > > > > > > > > that?
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > It is mentioned in the KIP
> > > > BuildingRemoteLogAuxState is
> > > > > > > > > > > introduced to
> > > > > > > > > > > > > > > > build the state like leader epoch sequence and
> > > > producer
> > > > > > > > > snapshots
> > > > > > > > > > > > > > > > before it starts fetching the data from the
> > > > leader. We
> > > > > > > will
> > > > > > > > > make
> > > > > > > > > > > it
> > > > > > > > > > > > > > > > clear in the KIP.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 5. Similarly, it would be worth summarizing the
> > > > > > behavior
> > > > > > > on
> > > > > > > > > > > unclean
> > > > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > election. There are several scenarios to
> > consider
> > > > here:
> > > > > > > data
> > > > > > > > > > > loss from
> > > > > > > > > > > > > > > > local log, data loss from remote log, data loss
> > > > from
> > > > > > > metadata
> > > > > > > > > > > topic,
> > > > > > > > > > > > > > etc.
> > > > > > > > > > > > > > > > It's worth describing these in detail.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > We mentioned the cases about unclean leader
> > > > election in
> > > > > > > the
> > > > > > > > > > > follower
> > > > > > > > > > > > > > > > fetch scenarios.
> > > > > > > > > > > > > > > > If there are errors while fetching data from
> > remote
> > > > > > > store or
> > > > > > > > > > > metadata
> > > > > > > > > > > > > > > > store, it will work the same way as it works
> > with
> > > > local
> > > > > > > log.
> > > > > > > > > It
> > > > > > > > > > > > > > > > returns the error back to the caller. Please
> > let us
> > > > > > know
> > > > > > > if
> > > > > > > > > I am
> > > > > > > > > > > > > > > > missing your point here.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 7. For a READ_COMMITTED FetchRequest, how do we
> > > > > > retrieve
> > > > > > > and
> > > > > > > > > > > return the
> > > > > > > > > > > > > > > > aborted transaction metadata?
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > When a fetch for a remote log is accessed, we
> > will
> > > > > > fetch
> > > > > > > > > aborted
> > > > > > > > > > > > > > > > transactions along with the segment if it is
> > not
> > > > found
> > > > > > > in the
> > > > > > > > > > > local
> > > > > > > > > > > > > > > > index cache. This includes the case of
> > transaction
> > > > > > index
> > > > > > > not
> > > > > > > > > > > existing
> > > > > > > > > > > > > > > > in the remote log segment. That means, the
> > cache
> > > > entry
> > > > > > > can be
> > > > > > > > > > > empty or
> > > > > > > > > > > > > > > > have a list of aborted transactions.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 8. The `LogSegmentData` class assumes that we
> > have
> > > > a
> > > > > > log
> > > > > > > > > segment,
> > > > > > > > > > > > > > offset
> > > > > > > > > > > > > > > > index, time index, transaction index, producer
> > > > snapshot
> > > > > > > and
> > > > > > > > > > > leader
> > > > > > > > > > > > > > epoch
> > > > > > > > > > > > > > > > index. How do we deal with cases where we do
> > not
> > > > have
> > > > > > > one or
> > > > > > > > > > > more of
> > > > > > > > > > > > > > > these?
> > > > > > > > > > > > > > > > For example, we may not have a transaction
> > index or
> > > > > > > producer
> > > > > > > > > > > snapshot
> > > > > > > > > > > > > > > for a
> > > > > > > > > > > > > > > > particular segment. The former is optional,
> > and the
> > > > > > > latter is
> > > > > > > > > > > only kept
> > > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > up to the 3 latest segments.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > This is a good point,  we discussed this in the
> > > > last
> > > > > > > meeting.
> > > > > > > > > > > > > > > > Transaction index is optional and we will copy
> > them
> > > > > > only
> > > > > > > if
> > > > > > > > > it
> > > > > > > > > > > exists.
> > > > > > > > > > > > > > > > We want to keep all the producer snapshots at
> > each
> > > > log
> > > > > > > > > segment
> > > > > > > > > > > rolling
> > > > > > > > > > > > > > > > and they can be removed if the log copying is
> > > > > > successful
> > > > > > > and
> > > > > > > > > it
> > > > > > > > > > > still
> > > > > > > > > > > > > > > > maintains the existing latest 3 segments, We
> > only
> > > > > > delete
> > > > > > > the
> > > > > > > > > > > producer
> > > > > > > > > > > > > > > > snapshots which have been copied to remote log
> > > > segments
> > > > > > > on
> > > > > > > > > > > leader.
> > > > > > > > > > > > > > > > Follower will keep the log segments beyond the
> > > > segments
> > > > > > > which
> > > > > > > > > > > have not
> > > > > > > > > > > > > > > > been copied to remote storage. We will update
> > the
> > > > KIP
> > > > > > > with
> > > > > > > > > these
> > > > > > > > > > > > > > > > details.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > Satish.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > On Thu, Sep 17, 2020 at 1:47 AM Dhruvil Shah <
> > > > > > > > > > > dhruvil@confluent.io>
> > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Hi Satish, Harsha,
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Thanks for the KIP. Few questions below:
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 1. Could you describe how retention would
> > work
> > > > with
> > > > > > > this
> > > > > > > > > KIP
> > > > > > > > > > > and
> > > > > > > > > > > > > > which
> > > > > > > > > > > > > > > > > threads are responsible for driving this
> > work? I
> > > > > > > believe
> > > > > > > > > there
> > > > > > > > > > > are 3
> > > > > > > > > > > > > > > kinds
> > > > > > > > > > > > > > > > > of retention processes we are looking at:
> > > > > > > > > > > > > > > > >   (a) Regular retention for data in tiered
> > > > storage as
> > > > > > > per
> > > > > > > > > > > configured
> > > > > > > > > > > > > > `
> > > > > > > > > > > > > > > > > retention.ms` / `retention.bytes`.
> > > > > > > > > > > > > > > > >   (b) Local retention for data in local
> > storage
> > > > as
> > > > > > per
> > > > > > > > > > > configured `
> > > > > > > > > > > > > > > > > local.log.retention.ms` /
> > > > > > `local.log.retention.bytes`
> > > > > > > > > > > > > > > > >   (c) Possibly regular retention for data in
> > > > local
> > > > > > > > > storage, if
> > > > > > > > > > > the
> > > > > > > > > > > > > > > tiering
> > > > > > > > > > > > > > > > > task is lagging or for data that is below
> > the log
> > > > > > start
> > > > > > > > > offset.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 2. When does a segment become eligible to be
> > > > tiered?
> > > > > > > Is it
> > > > > > > > > as
> > > > > > > > > > > soon as
> > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > segment is rolled and the end offset is less
> > > > than the
> > > > > > > last
> > > > > > > > > > > stable
> > > > > > > > > > > > > > > offset as
> > > > > > > > > > > > > > > > > mentioned in the KIP? I wonder if we need to
> > > > consider
> > > > > > > other
> > > > > > > > > > > > > > parameters
> > > > > > > > > > > > > > > too,
> > > > > > > > > > > > > > > > > like the highwatermark so that we are
> > guaranteed
> > > > that
> > > > > > > what
> > > > > > > > > we
> > > > > > > > > > > are
> > > > > > > > > > > > > > > tiering
> > > > > > > > > > > > > > > > > has been committed to the log and accepted
> > by the
> > > > > > ISR.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 3. The section on "Follower Fetch Scenarios"
> > is
> > > > > > useful
> > > > > > > but
> > > > > > > > > is
> > > > > > > > > > > a bit
> > > > > > > > > > > > > > > > > difficult to parse at the moment. It would be
> > > > useful
> > > > > > to
> > > > > > > > > > > summarize the
> > > > > > > > > > > > > > > > > changes we need in the ReplicaFetcher.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 4. Related to the above, it's a bit unclear
> > how
> > > > we
> > > > > > are
> > > > > > > > > > > planning on
> > > > > > > > > > > > > > > > > restoring the producer state for a new
> > replica.
> > > > Could
> > > > > > > you
> > > > > > > > > > > expand on
> > > > > > > > > > > > > > > that?
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 5. Similarly, it would be worth summarizing
> > the
> > > > > > > behavior on
> > > > > > > > > > > unclean
> > > > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > > election. There are several scenarios to
> > consider
> > > > > > here:
> > > > > > > > > data
> > > > > > > > > > > loss
> > > > > > > > > > > > > > from
> > > > > > > > > > > > > > > > > local log, data loss from remote log, data
> > loss
> > > > from
> > > > > > > > > metadata
> > > > > > > > > > > topic,
> > > > > > > > > > > > > > > etc.
> > > > > > > > > > > > > > > > > It's worth describing these in detail.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 6. It would be useful to add details about
> > how we
> > > > > > plan
> > > > > > > on
> > > > > > > > > using
> > > > > > > > > > > > > > > RocksDB in
> > > > > > > > > > > > > > > > > the default implementation of
> > > > > > > `RemoteLogMetadataManager`.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 7. For a READ_COMMITTED FetchRequest, how do
> > we
> > > > > > > retrieve
> > > > > > > > > and
> > > > > > > > > > > return
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > aborted transaction metadata?
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 8. The `LogSegmentData` class assumes that we
> > > > have a
> > > > > > > log
> > > > > > > > > > > segment,
> > > > > > > > > > > > > > > offset
> > > > > > > > > > > > > > > > > index, time index, transaction index,
> > producer
> > > > > > > snapshot and
> > > > > > > > > > > leader
> > > > > > > > > > > > > > > epoch
> > > > > > > > > > > > > > > > > index. How do we deal with cases where we do
> > not
> > > > have
> > > > > > > one
> > > > > > > > > or
> > > > > > > > > > > more of
> > > > > > > > > > > > > > > these?
> > > > > > > > > > > > > > > > > For example, we may not have a transaction
> > index
> > > > or
> > > > > > > > > producer
> > > > > > > > > > > snapshot
> > > > > > > > > > > > > > > for a
> > > > > > > > > > > > > > > > > particular segment. The former is optional,
> > and
> > > > the
> > > > > > > latter
> > > > > > > > > is
> > > > > > > > > > > only
> > > > > > > > > > > > > > > kept for
> > > > > > > > > > > > > > > > > up to the 3 latest segments.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > > Dhruvil
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > On Mon, Sep 7, 2020 at 6:54 PM Harsha Ch <
> > > > > > > > > harsha.ch@gmail.com>
> > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > Hi All,
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > We are all working through the last meeting
> > > > > > feedback.
> > > > > > > > > I'll
> > > > > > > > > > > cancel
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > tomorrow 's meeting and we can meanwhile
> > > > continue
> > > > > > our
> > > > > > > > > > > discussion in
> > > > > > > > > > > > > > > mailing
> > > > > > > > > > > > > > > > > > list. We can start the regular meeting from
> > > > next
> > > > > > week
> > > > > > > > > > > onwards.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > Harsha
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > On Fri, Sep 04, 2020 at 8:41 AM, Satish
> > > > Duggana <
> > > > > > > > > > > > > > > satish.duggana@gmail.com
> > > > > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Hi Jun,
> > > > > > > > > > > > > > > > > > > Thanks for your thorough review and
> > comments.
> > > > > > > Please
> > > > > > > > > find
> > > > > > > > > > > the
> > > > > > > > > > > > > > > inline
> > > > > > > > > > > > > > > > > > > replies below.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 600. The topic deletion logic needs more
> > > > details.
> > > > > > > > > > > > > > > > > > > 600.1 The KIP mentions "The controller
> > > > considers
> > > > > > > the
> > > > > > > > > topic
> > > > > > > > > > > > > > > partition is
> > > > > > > > > > > > > > > > > > > deleted only when it determines that
> > there
> > > > are no
> > > > > > > log
> > > > > > > > > > > segments
> > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > that
> > > > > > > > > > > > > > > > > > > topic partition by using RLMM". How is
> > this
> > > > done?
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > It uses RLMM#listSegments() returns all
> > the
> > > > > > > segments
> > > > > > > > > for
> > > > > > > > > > > the
> > > > > > > > > > > > > > given
> > > > > > > > > > > > > > > topic
> > > > > > > > > > > > > > > > > > > partition.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 600.2 "If the delete option is enabled
> > then
> > > > the
> > > > > > > leader
> > > > > > > > > > > will stop
> > > > > > > > > > > > > > > RLM task
> > > > > > > > > > > > > > > > > > > and stop processing and it sets all the
> > > > remote
> > > > > > log
> > > > > > > > > segment
> > > > > > > > > > > > > > > metadata of
> > > > > > > > > > > > > > > > > > > that partition with a delete marker and
> > > > publishes
> > > > > > > them
> > > > > > > > > to
> > > > > > > > > > > RLMM."
> > > > > > > > > > > > > > We
> > > > > > > > > > > > > > > > > > > discussed this earlier. When a topic is
> > being
> > > > > > > deleted,
> > > > > > > > > > > there may
> > > > > > > > > > > > > > > not be a
> > > > > > > > > > > > > > > > > > > leader for the deleted partition.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > This is a good point. As suggested in the
> > > > > > meeting,
> > > > > > > we
> > > > > > > > > will
> > > > > > > > > > > add a
> > > > > > > > > > > > > > > separate
> > > > > > > > > > > > > > > > > > > section for topic/partition deletion
> > > > lifecycle
> > > > > > and
> > > > > > > this
> > > > > > > > > > > scenario
> > > > > > > > > > > > > > > will be
> > > > > > > > > > > > > > > > > > > addressed.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 601. Unclean leader election
> > > > > > > > > > > > > > > > > > > 601.1 Scenario 1: new empty follower
> > > > > > > > > > > > > > > > > > > After step 1, the follower restores up to
> > > > offset
> > > > > > > 3. So
> > > > > > > > > why
> > > > > > > > > > > does
> > > > > > > > > > > > > > it
> > > > > > > > > > > > > > > have
> > > > > > > > > > > > > > > > > > > LE-2 <
> > > > https://issues.apache.org/jira/browse/LE-2
> > > > > > >
> > > > > > > at
> > > > > > > > > > > offset 5?
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Nice catch. It was showing the leader
> > epoch
> > > > > > fetched
> > > > > > > > > from
> > > > > > > > > > > the
> > > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > > > storage. It should be shown with the
> > > > truncated
> > > > > > till
> > > > > > > > > offset
> > > > > > > > > > > 3.
> > > > > > > > > > > > > > > Updated the
> > > > > > > > > > > > > > > > > > > KIP.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 601.2 senario 5: After Step 3, leader A
> > has
> > > > > > > > > inconsistent
> > > > > > > > > > > data
> > > > > > > > > > > > > > > between its
> > > > > > > > > > > > > > > > > > > local and the tiered data. For example.
> > > > offset 3
> > > > > > > has
> > > > > > > > > msg 3
> > > > > > > > > > > LE-0
> > > > > > > > > > > > > > > <https://issues.apache.org/jira/browse/LE-0>
> > > > locally,
> > > > > > > > > > > > > > > > > > > but msg 5 LE-1 <
> > > > > > > > > https://issues.apache.org/jira/browse/LE-1>
> > > > > > > > > > > in
> > > > > > > > > > > > > > > the remote store. While it's ok for the unclean
> > > > leader
> > > > > > > > > > > > > > > > > > > to lose data, it should still return
> > > > consistent
> > > > > > > data,
> > > > > > > > > > > whether
> > > > > > > > > > > > > > it's
> > > > > > > > > > > > > > > from
> > > > > > > > > > > > > > > > > > > the local or the remote store.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > There is no inconsistency here as LE-0
> > > > > > > > > > > > > > > <https://issues.apache.org/jira/browse/LE-0>
> > > > offsets are
> > > > > > > [0,
> > > > > > > > > 4]
> > > > > > > > > > > and LE-2
> > > > > > > > > > > > > > > <https://issues.apache.org/jira/browse/LE-2>:
> > > > > > > > > > > > > > > > > > > [5, ]. It will always get the right
> > records
> > > > for
> > > > > > the
> > > > > > > > > given
> > > > > > > > > > > offset
> > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > leader epoch. In case of remote, RSM is
> > > > invoked
> > > > > > to
> > > > > > > get
> > > > > > > > > the
> > > > > > > > > > > remote
> > > > > > > > > > > > > > > log
> > > > > > > > > > > > > > > > > > > segment that contains the given offset
> > with
> > > > the
> > > > > > > leader
> > > > > > > > > > > epoch.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 601.4 It seems that retention is based on
> > > > > > > > > > > > > > > > > > > listRemoteLogSegments(TopicPartition
> > > > > > > topicPartition,
> > > > > > > > > long
> > > > > > > > > > > > > > > leaderEpoch).
> > > > > > > > > > > > > > > > > > > When there is an unclean leader election,
> > > > it's
> > > > > > > possible
> > > > > > > > > > > for the
> > > > > > > > > > > > > > new
> > > > > > > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > > > > to not to include certain epochs in its
> > epoch
> > > > > > > cache.
> > > > > > > > > How
> > > > > > > > > > > are
> > > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > > > segments associated with those epochs
> > being
> > > > > > > cleaned?
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > That is a good point. This leader will
> > also
> > > > > > > cleanup the
> > > > > > > > > > > epochs
> > > > > > > > > > > > > > > earlier to
> > > > > > > > > > > > > > > > > > > its start leader epoch and delete those
> > > > segments.
> > > > > > > It
> > > > > > > > > gets
> > > > > > > > > > > the
> > > > > > > > > > > > > > > earliest
> > > > > > > > > > > > > > > > > > > epoch for a partition and starts deleting
> > > > > > segments
> > > > > > > from
> > > > > > > > > > > that
> > > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > > > epoch.
> > > > > > > > > > > > > > > > > > > We need one more API in RLMM to get the
> > > > earliest
> > > > > > > leader
> > > > > > > > > > > epoch.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 601.5 The KIP discusses the handling of
> > > > unclean
> > > > > > > leader
> > > > > > > > > > > elections
> > > > > > > > > > > > > > > for user
> > > > > > > > > > > > > > > > > > > topics. What about unclean leader
> > elections
> > > > on
> > > > > > > > > > > > > > > > > > > __remote_log_segment_metadata?
> > > > > > > > > > > > > > > > > > > This is the same as other system topics
> > like
> > > > > > > > > > > consumer_offsets,
> > > > > > > > > > > > > > > > > > > __transaction_state topics. As discussed
> > in
> > > > the
> > > > > > > > > meeting,
> > > > > > > > > > > we will
> > > > > > > > > > > > > > > add the
> > > > > > > > > > > > > > > > > > > behavior of __remote_log_segment_metadata
> > > > topic’s
> > > > > > > > > unclean
> > > > > > > > > > > leader
> > > > > > > > > > > > > > > > > > > truncation.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 602. It would be useful to clarify the
> > > > > > limitations
> > > > > > > in
> > > > > > > > > the
> > > > > > > > > > > initial
> > > > > > > > > > > > > > > > > > release.
> > > > > > > > > > > > > > > > > > > The KIP mentions not supporting compacted
> > > > topics.
> > > > > > > What
> > > > > > > > > > > about JBOD
> > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > changing the configuration of a topic
> > from
> > > > delete
> > > > > > > to
> > > > > > > > > > > compact
> > > > > > > > > > > > > > after
> > > > > > > > > > > > > > > > > > remote.
> > > > > > > > > > > > > > > > > > > log. storage. enable (
> > > > > > > > > http://remote.log.storage.enable/
> > > > > > > > > > > ) is
> > > > > > > > > > > > > > > enabled?
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > This was updated in the KIP earlier.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 603. RLM leader tasks:
> > > > > > > > > > > > > > > > > > > 603.1"It checks for rolled over
> > LogSegments
> > > > > > (which
> > > > > > > have
> > > > > > > > > > > the last
> > > > > > > > > > > > > > > message
> > > > > > > > > > > > > > > > > > > offset less than last stable offset of
> > that
> > > > topic
> > > > > > > > > > > partition) and
> > > > > > > > > > > > > > > copies
> > > > > > > > > > > > > > > > > > > them along with their
> > offset/time/transaction
> > > > > > > indexes
> > > > > > > > > and
> > > > > > > > > > > leader
> > > > > > > > > > > > > > > epoch
> > > > > > > > > > > > > > > > > > > cache to the remote tier." It needs to
> > copy
> > > > the
> > > > > > > > > producer
> > > > > > > > > > > snapshot
> > > > > > > > > > > > > > > too.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Right. It copies producer snapshots too
> > as
> > > > > > > mentioned in
> > > > > > > > > > > > > > > LogSegmentData.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 603.2 "Local logs are not cleaned up till
> > > > those
> > > > > > > > > segments
> > > > > > > > > > > are
> > > > > > > > > > > > > > copied
> > > > > > > > > > > > > > > > > > > successfully to remote even though their
> > > > > > retention
> > > > > > > > > > > time/size is
> > > > > > > > > > > > > > > reached"
> > > > > > > > > > > > > > > > > > > This seems weird. If the tiering stops
> > > > because
> > > > > > the
> > > > > > > > > remote
> > > > > > > > > > > store
> > > > > > > > > > > > > > is
> > > > > > > > > > > > > > > not
> > > > > > > > > > > > > > > > > > > available, we don't want the local data
> > to
> > > > grow
> > > > > > > > > forever.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > It was clarified in the discussion that
> > the
> > > > > > > comment was
> > > > > > > > > > > more
> > > > > > > > > > > > > > about
> > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > local storage goes beyond the
> > log.retention.
> > > > The
> > > > > > > above
> > > > > > > > > > > statement
> > > > > > > > > > > > > > > is about
> > > > > > > > > > > > > > > > > > > local.log.retention but not for the
> > complete
> > > > > > > > > > > log.retention. When
> > > > > > > > > > > > > > it
> > > > > > > > > > > > > > > > > > > reaches the log.retention then it will
> > > > delete the
> > > > > > > local
> > > > > > > > > > > logs even
> > > > > > > > > > > > > > > though
> > > > > > > > > > > > > > > > > > > those are not copied to remote storage.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 604. "RLM maintains a bounded
> > cache(possibly
> > > > LRU)
> > > > > > > of
> > > > > > > > > the
> > > > > > > > > > > index
> > > > > > > > > > > > > > > files of
> > > > > > > > > > > > > > > > > > > remote log segments to avoid multiple
> > index
> > > > > > fetches
> > > > > > > > > from
> > > > > > > > > > > the
> > > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > > > storage. These indexes can be used in the
> > > > same
> > > > > > way
> > > > > > > as
> > > > > > > > > local
> > > > > > > > > > > > > > segment
> > > > > > > > > > > > > > > > > > > indexes are used." Could you provide more
> > > > details
> > > > > > > on
> > > > > > > > > this?
> > > > > > > > > > > Are
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > indexes
> > > > > > > > > > > > > > > > > > > cached in memory or on disk? If on disk,
> > > > where
> > > > > > are
> > > > > > > they
> > > > > > > > > > > stored?
> > > > > > > > > > > > > > > Are the
> > > > > > > > > > > > > > > > > > > cached indexes bound by a certain size?
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > These are cached on disk and stored in
> > > > log.dir
> > > > > > > with a
> > > > > > > > > name
> > > > > > > > > > > > > > > > > > > “__remote_log_index_cache”. They are
> > bound
> > > > by the
> > > > > > > total
> > > > > > > > > > > size.
> > > > > > > > > > > > > > This
> > > > > > > > > > > > > > > will
> > > > > > > > > > > > > > > > > > be
> > > > > > > > > > > > > > > > > > > exposed as a user configuration,
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 605. BuildingRemoteLogAux
> > > > > > > > > > > > > > > > > > > 605.1 In this section, two options are
> > > > listed.
> > > > > > > Which
> > > > > > > > > one is
> > > > > > > > > > > > > > chosen?
> > > > > > > > > > > > > > > > > > > Option-2, updated the KIP.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 605.2 In option 2, it says "Build the
> > local
> > > > > > leader
> > > > > > > > > epoch
> > > > > > > > > > > cache by
> > > > > > > > > > > > > > > cutting
> > > > > > > > > > > > > > > > > > > the leader epoch sequence received from
> > > > remote
> > > > > > > storage
> > > > > > > > > to
> > > > > > > > > > > [LSO,
> > > > > > > > > > > > > > > ELO].
> > > > > > > > > > > > > > > > > > (LSO
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > = log start offset)." We need to do the
> > same
> > > > > > thing
> > > > > > > for
> > > > > > > > > the
> > > > > > > > > > > > > > producer
> > > > > > > > > > > > > > > > > > > snapshot. However, it's hard to cut the
> > > > producer
> > > > > > > > > snapshot
> > > > > > > > > > > to an
> > > > > > > > > > > > > > > earlier
> > > > > > > > > > > > > > > > > > > offset. Another option is to simply take
> > the
> > > > > > > lastOffset
> > > > > > > > > > > from the
> > > > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > > > segment and use that as the starting
> > fetch
> > > > offset
> > > > > > > in
> > > > > > > > > the
> > > > > > > > > > > > > > follower.
> > > > > > > > > > > > > > > This
> > > > > > > > > > > > > > > > > > > avoids the need for cutting.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Right, this was mentioned in the
> > > > “transactional
> > > > > > > > > support”
> > > > > > > > > > > section
> > > > > > > > > > > > > > > about
> > > > > > > > > > > > > > > > > > > adding these details.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 606. ListOffsets: Since we need a version
> > > > bump,
> > > > > > > could
> > > > > > > > > you
> > > > > > > > > > > > > > document
> > > > > > > > > > > > > > > it
> > > > > > > > > > > > > > > > > > > under a protocol change section?
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Sure, we will update the KIP.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 607. "LogStartOffset of a topic can
> > point to
> > > > > > > either of
> > > > > > > > > > > local
> > > > > > > > > > > > > > > segment or
> > > > > > > > > > > > > > > > > > > remote segment but it is initialised and
> > > > > > > maintained in
> > > > > > > > > the
> > > > > > > > > > > Log
> > > > > > > > > > > > > > > class like
> > > > > > > > > > > > > > > > > > > now. This is already maintained in `Log`
> > > > class
> > > > > > > while
> > > > > > > > > > > loading the
> > > > > > > > > > > > > > > logs and
> > > > > > > > > > > > > > > > > > > it can also be fetched from
> > > > > > > RemoteLogMetadataManager."
> > > > > > > > > > > What will
> > > > > > > > > > > > > > > happen
> > > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > > the existing logic (e.g. log recovery)
> > that
> > > > > > > currently
> > > > > > > > > > > depends on
> > > > > > > > > > > > > > > > > > > logStartOffset but assumes it's local?
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > They use a field called
> > localLogStartOffset
> > > > which
> > > > > > > is
> > > > > > > > > the
> > > > > > > > > > > local
> > > > > > > > > > > > > > log
> > > > > > > > > > > > > > > start
> > > > > > > > > > > > > > > > > > > offset..
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 608. Handle expired remote segment: How
> > does
> > > > it
> > > > > > > pick
> > > > > > > > > up new
> > > > > > > > > > > > > > > > > > logStartOffset
> > > > > > > > > > > > > > > > > > > from deleteRecords?
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Good point. This was not addressed in the
> > > > KIP.
> > > > > > Will
> > > > > > > > > update
> > > > > > > > > > > the
> > > > > > > > > > > > > > KIP
> > > > > > > > > > > > > > > on how
> > > > > > > > > > > > > > > > > > > the RLM task handles this scenario.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 609. RLMM message format:
> > > > > > > > > > > > > > > > > > > 609.1 It includes both MaxTimestamp and
> > > > > > > EventTimestamp.
> > > > > > > > > > > Where
> > > > > > > > > > > > > > does
> > > > > > > > > > > > > > > it get
> > > > > > > > > > > > > > > > > > > both since the message in the log only
> > > > contains
> > > > > > one
> > > > > > > > > > > timestamp?
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > `EventTimeStamp` is the timestamp at
> > which
> > > > that
> > > > > > > segment
> > > > > > > > > > > metadata
> > > > > > > > > > > > > > > event is
> > > > > > > > > > > > > > > > > > > generated. This is more for audits.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 609.2 If we change just the state (e.g.
> > to
> > > > > > > > > > > DELETE_STARTED), it
> > > > > > > > > > > > > > > seems it's
> > > > > > > > > > > > > > > > > > > wasteful to have to include all other
> > fields
> > > > not
> > > > > > > > > changed.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > This is a good point. We thought about
> > > > > > incremental
> > > > > > > > > > > updates. But
> > > > > > > > > > > > > > we
> > > > > > > > > > > > > > > want
> > > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > > make sure all the events are in the
> > expected
> > > > > > order
> > > > > > > and
> > > > > > > > > take
> > > > > > > > > > > > > > action
> > > > > > > > > > > > > > > based
> > > > > > > > > > > > > > > > > > > on the latest event. Will think through
> > the
> > > > > > > approaches
> > > > > > > > > in
> > > > > > > > > > > detail
> > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > update here.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 609.3 Could you document which process
> > makes
> > > > the
> > > > > > > > > following
> > > > > > > > > > > > > > > transitions
> > > > > > > > > > > > > > > > > > > DELETE_MARKED, DELETE_STARTED,
> > > > DELETE_FINISHED?
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Okay, will document more details.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 610. remote.log.reader.max.pending.tasks:
> > > > > > "Maximum
> > > > > > > > > remote
> > > > > > > > > > > log
> > > > > > > > > > > > > > > reader
> > > > > > > > > > > > > > > > > > > thread pool task queue size. If the task
> > > > queue is
> > > > > > > full,
> > > > > > > > > > > broker
> > > > > > > > > > > > > > > will stop
> > > > > > > > > > > > > > > > > > > reading remote log segments." What does
> > the
> > > > > > broker
> > > > > > > do
> > > > > > > > > if
> > > > > > > > > > > the
> > > > > > > > > > > > > > queue
> > > > > > > > > > > > > > > is
> > > > > > > > > > > > > > > > > > > full?
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > It returns an error for this topic
> > partition.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > 611. What do we return if the request
> > > > > > offset/epoch
> > > > > > > > > doesn't
> > > > > > > > > > > exist
> > > > > > > > > > > > > > > in the
> > > > > > > > > > > > > > > > > > > following API?
> > > > > > > > > > > > > > > > > > > RemoteLogSegmentMetadata
> > > > > > > > > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > > > > > > > > > > > topicPartition, long offset, int
> > > > epochForOffset)
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > This returns null. But we prefer to
> > update
> > > > the
> > > > > > > return
> > > > > > > > > type
> > > > > > > > > > > as
> > > > > > > > > > > > > > > Optional
> > > > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > return Empty if that does not exist.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > > > > Satish.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > On Tue, Sep 1, 2020 at 9:45 AM Jun Rao <
> > jun@
> > > > > > > > > confluent.
> > > > > > > > > > > io (
> > > > > > > > > > > > > > > > > > > jun@confluent.io ) > wrote:
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >> Hi, Satish,
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >> Thanks for the updated KIP. Made another
> > > > pass. A
> > > > > > > few
> > > > > > > > > more
> > > > > > > > > > > > > > comments
> > > > > > > > > > > > > > > > > > below.
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >> 600. The topic deletion logic needs more
> > > > > > details.
> > > > > > > > > > > > > > > > > > >> 600.1 The KIP mentions "The controller
> > > > considers
> > > > > > > the
> > > > > > > > > topic
> > > > > > > > > > > > > > > partition is
> > > > > > > > > > > > > > > > > > >> deleted only when it determines that
> > there
> > > > are
> > > > > > no
> > > > > > > log
> > > > > > > > > > > segments
> > > > > > > > > > > > > > > for that
> > > > > > > > > > > > > > > > > > >> topic partition by using RLMM". How is
> > this
> > > > > > done?
> > > > > > > > > 600.2
> > > > > > > > > > > "If the
> > > > > > > > > > > > > > > delete
> > > > > > > > > > > > > > > > > > >> option is enabled then the leader will
> > stop
> > > > RLM
> > > > > > > task
> > > > > > > > > and
> > > > > > > > > > > stop
> > > > > > > > > > > > > > > processing
> > > > > > > > > > > > > > > > > > >> and it sets all the remote log segment
> > > > metadata
> > > > > > of
> > > > > > > > > that
> > > > > > > > > > > > > > partition
> > > > > > > > > > > > > > > with a
> > > > > > > > > > > > > > > > > > >> delete marker and publishes them to
> > RLMM."
> > > > We
> > > > > > > > > discussed
> > > > > > > > > > > this
> > > > > > > > > > > > > > > earlier.
> > > > > > > > > > > > > > > > > > When
> > > > > > > > > > > > > > > > > > >> a topic is being deleted, there may not
> > be a
> > > > > > > leader
> > > > > > > > > for
> > > > > > > > > > > the
> > > > > > > > > > > > > > > deleted
> > > > > > > > > > > > > > > > > > >> partition.
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >> 601. Unclean leader election
> > > > > > > > > > > > > > > > > > >> 601.1 Scenario 1: new empty follower
> > > > > > > > > > > > > > > > > > >> After step 1, the follower restores up
> > to
> > > > offset
> > > > > > > 3. So
> > > > > > > > > > > why does
> > > > > > > > > > > > > > > it have
> > > > > > > > > > > > > > > > > > >> LE-2 <
> > > > > > https://issues.apache.org/jira/browse/LE-2>
> > > > > > > at
> > > > > > > > > > > offset 5?
> > > > > > > > > > > > > > > > > > >> 601.2 senario 5: After Step 3, leader A
> > has
> > > > > > > > > inconsistent
> > > > > > > > > > > data
> > > > > > > > > > > > > > > between
> > > > > > > > > > > > > > > > > > its
> > > > > > > > > > > > > > > > > > >> local and the tiered data. For example.
> > > > offset 3
> > > > > > > has
> > > > > > > > > msg
> > > > > > > > > > > 3 LE-0
> > > > > > > > > > > > > > > <https://issues.apache.org/jira/browse/LE-0>
> > > > locally,
> > > > > > > > > > > > > > > > > > >> but msg 5 LE-1 <
> > > > > > > > > > > https://issues.apache.org/jira/browse/LE-1> in
> > > > > > > > > > > > > > > the remote store. While it's ok for the unclean
> > > > leader
> > > > > > > > > > > > > > > > > > >> to lose data, it should still return
> > > > consistent
> > > > > > > data,
> > > > > > > > > > > whether
> > > > > > > > > > > > > > > it's from
> > > > > > > > > > > > > > > > > > >> the local or the remote store.
> > > > > > > > > > > > > > > > > > >> 601.3 The follower picks up log start
> > offset
> > > > > > > using the
> > > > > > > > > > > following
> > > > > > > > > > > > > > > api.
> > > > > > > > > > > > > > > > > > >> Suppose that we have 3 remote segments
> > (LE,
> > > > > > > > > > > SegmentStartOffset)
> > > > > > > > > > > > > > > as (2,
> > > > > > > > > > > > > > > > > > >> 10),
> > > > > > > > > > > > > > > > > > >> (3, 20) and (7, 15) due to an unclean
> > leader
> > > > > > > election.
> > > > > > > > > > > Using the
> > > > > > > > > > > > > > > > > > following
> > > > > > > > > > > > > > > > > > >> api will cause logStartOffset to go
> > backward
> > > > > > from
> > > > > > > 20
> > > > > > > > > to
> > > > > > > > > > > 15. How
> > > > > > > > > > > > > > > do we
> > > > > > > > > > > > > > > > > > >> prevent that?
> > > > > > > > > > > > > > > > > > >> earliestLogOffset(TopicPartition
> > > > topicPartition,
> > > > > > > int
> > > > > > > > > > > > > > leaderEpoch)
> > > > > > > > > > > > > > > 601.4
> > > > > > > > > > > > > > > > > > It
> > > > > > > > > > > > > > > > > > >> seems that retention is based on
> > > > > > > > > > > > > > > > > > >> listRemoteLogSegments(TopicPartition
> > > > > > > topicPartition,
> > > > > > > > > long
> > > > > > > > > > > > > > > leaderEpoch).
> > > > > > > > > > > > > > > > > > >> When there is an unclean leader
> > election,
> > > > it's
> > > > > > > > > possible
> > > > > > > > > > > for the
> > > > > > > > > > > > > > > new
> > > > > > > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > > > >> to not to include certain epochs in its
> > > > epoch
> > > > > > > cache.
> > > > > > > > > How
> > > > > > > > > > > are
> > > > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > > >> segments associated with those epochs
> > being
> > > > > > > cleaned?
> > > > > > > > > > > 601.5 The
> > > > > > > > > > > > > > KIP
> > > > > > > > > > > > > > > > > > >> discusses the handling of unclean leader
> > > > > > > elections for
> > > > > > > > > > > user
> > > > > > > > > > > > > > > topics. What
> > > > > > > > > > > > > > > > > > >> about unclean leader elections on
> > > > > > > > > > > > > > > > > > >> __remote_log_segment_metadata?
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >> 602. It would be useful to clarify the
> > > > > > > limitations in
> > > > > > > > > the
> > > > > > > > > > > > > > initial
> > > > > > > > > > > > > > > > > > release.
> > > > > > > > > > > > > > > > > > >> The KIP mentions not supporting
> > compacted
> > > > > > topics.
> > > > > > > What
> > > > > > > > > > > about
> > > > > > > > > > > > > > JBOD
> > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > >> changing the configuration of a topic
> > from
> > > > > > delete
> > > > > > > to
> > > > > > > > > > > compact
> > > > > > > > > > > > > > after
> > > > > > > > > > > > > > > > > > remote.
> > > > > > > > > > > > > > > > > > >> log. storage. enable (
> > > > > > > > > http://remote.log.storage.enable/
> > > > > > > > > > > ) is
> > > > > > > > > > > > > > > enabled?
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >> 603. RLM leader tasks:
> > > > > > > > > > > > > > > > > > >> 603.1"It checks for rolled over
> > LogSegments
> > > > > > (which
> > > > > > > > > have
> > > > > > > > > > > the last
> > > > > > > > > > > > > > > message
> > > > > > > > > > > > > > > > > > >> offset less than last stable offset of
> > that
> > > > > > topic
> > > > > > > > > > > partition) and
> > > > > > > > > > > > > > > copies
> > > > > > > > > > > > > > > > > > >> them along with their
> > > > offset/time/transaction
> > > > > > > indexes
> > > > > > > > > and
> > > > > > > > > > > leader
> > > > > > > > > > > > > > > epoch
> > > > > > > > > > > > > > > > > > >> cache to the remote tier." It needs to
> > copy
> > > > the
> > > > > > > > > producer
> > > > > > > > > > > > > > snapshot
> > > > > > > > > > > > > > > too.
> > > > > > > > > > > > > > > > > > >> 603.2 "Local logs are not cleaned up
> > till
> > > > those
> > > > > > > > > segments
> > > > > > > > > > > are
> > > > > > > > > > > > > > > copied
> > > > > > > > > > > > > > > > > > >> successfully to remote even though their
> > > > > > retention
> > > > > > > > > > > time/size is
> > > > > > > > > > > > > > > reached"
> > > > > > > > > > > > > > > > > > >> This seems weird. If the tiering stops
> > > > because
> > > > > > the
> > > > > > > > > remote
> > > > > > > > > > > store
> > > > > > > > > > > > > > > is not
> > > > > > > > > > > > > > > > > > >> available, we don't want the local data
> > to
> > > > grow
> > > > > > > > > forever.
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >> 604. "RLM maintains a bounded
> > cache(possibly
> > > > > > LRU)
> > > > > > > of
> > > > > > > > > the
> > > > > > > > > > > index
> > > > > > > > > > > > > > > files of
> > > > > > > > > > > > > > > > > > >> remote log segments to avoid multiple
> > index
> > > > > > > fetches
> > > > > > > > > from
> > > > > > > > > > > the
> > > > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > > >> storage. These indexes can be used in
> > the
> > > > same
> > > > > > > way as
> > > > > > > > > > > local
> > > > > > > > > > > > > > > segment
> > > > > > > > > > > > > > > > > > >> indexes are used." Could you provide
> > more
> > > > > > details
> > > > > > > on
> > > > > > > > > > > this? Are
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > indexes
> > > > > > > > > > > > > > > > > > >> cached in memory or on disk? If on disk,
> > > > where
> > > > > > are
> > > > > > > > > they
> > > > > > > > > > > stored?
> > > > > > > > > > > > > > > Are the
> > > > > > > > > > > > > > > > > > >> cached indexes bound by a certain size?
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >> 605. BuildingRemoteLogAux
> > > > > > > > > > > > > > > > > > >> 605.1 In this section, two options are
> > > > listed.
> > > > > > > Which
> > > > > > > > > one
> > > > > > > > > > > is
> > > > > > > > > > > > > > > chosen?
> > > > > > > > > > > > > > > > > > 605.2
> > > > > > > > > > > > > > > > > > >> In option 2, it says "Build the local
> > leader
> > > > > > epoch
> > > > > > > > > cache
> > > > > > > > > > > by
> > > > > > > > > > > > > > > cutting the
> > > > > > > > > > > > > > > > > > >> leader epoch sequence received from
> > remote
> > > > > > > storage to
> > > > > > > > > > > [LSO,
> > > > > > > > > > > > > > ELO].
> > > > > > > > > > > > > > > (LSO
> > > > > > > > > > > > > > > > > > >> = log start offset)." We need to do the
> > same
> > > > > > thing
> > > > > > > > > for the
> > > > > > > > > > > > > > > producer
> > > > > > > > > > > > > > > > > > >> snapshot. However, it's hard to cut the
> > > > producer
> > > > > > > > > snapshot
> > > > > > > > > > > to an
> > > > > > > > > > > > > > > earlier
> > > > > > > > > > > > > > > > > > >> offset. Another option is to simply
> > take the
> > > > > > > > > lastOffset
> > > > > > > > > > > from the
> > > > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > > >> segment and use that as the starting
> > fetch
> > > > > > offset
> > > > > > > in
> > > > > > > > > the
> > > > > > > > > > > > > > > follower. This
> > > > > > > > > > > > > > > > > > >> avoids the need for cutting.
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >> 606. ListOffsets: Since we need a
> > version
> > > > bump,
> > > > > > > could
> > > > > > > > > you
> > > > > > > > > > > > > > > document it
> > > > > > > > > > > > > > > > > > >> under a protocol change section?
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >> 607. "LogStartOffset of a topic can
> > point to
> > > > > > > either of
> > > > > > > > > > > local
> > > > > > > > > > > > > > > segment or
> > > > > > > > > > > > > > > > > > >> remote segment but it is initialised and
> > > > > > > maintained in
> > > > > > > > > > > the Log
> > > > > > > > > > > > > > > class
> > > > > > > > > > > > > > > > > > like
> > > > > > > > > > > > > > > > > > >> now. This is already maintained in `Log`
> > > > class
> > > > > > > while
> > > > > > > > > > > loading the
> > > > > > > > > > > > > > > logs
> > > > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > >> it can also be fetched from
> > > > > > > RemoteLogMetadataManager."
> > > > > > > > > > > What will
> > > > > > > > > > > > > > > happen
> > > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > >> the existing logic (e.g. log recovery)
> > that
> > > > > > > currently
> > > > > > > > > > > depends on
> > > > > > > > > > > > > > > > > > >> logStartOffset but assumes it's local?
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >> 608. Handle expired remote segment: How
> > > > does it
> > > > > > > pick
> > > > > > > > > up
> > > > > > > > > > > new
> > > > > > > > > > > > > > > > > > logStartOffset
> > > > > > > > > > > > > > > > > > >> from deleteRecords?
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >> 609. RLMM message format:
> > > > > > > > > > > > > > > > > > >> 609.1 It includes both MaxTimestamp and
> > > > > > > > > EventTimestamp.
> > > > > > > > > > > Where
> > > > > > > > > > > > > > > does it
> > > > > > > > > > > > > > > > > > get
> > > > > > > > > > > > > > > > > > >> both since the message in the log only
> > > > contains
> > > > > > > one
> > > > > > > > > > > timestamp?
> > > > > > > > > > > > > > > 609.2 If
> > > > > > > > > > > > > > > > > > we
> > > > > > > > > > > > > > > > > > >> change just the state (e.g. to
> > > > DELETE_STARTED),
> > > > > > it
> > > > > > > > > seems
> > > > > > > > > > > it's
> > > > > > > > > > > > > > > wasteful
> > > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > >> have to include all other fields not
> > > > changed.
> > > > > > > 609.3
> > > > > > > > > Could
> > > > > > > > > > > you
> > > > > > > > > > > > > > > document
> > > > > > > > > > > > > > > > > > >> which process makes the following
> > > > transitions
> > > > > > > > > > > DELETE_MARKED,
> > > > > > > > > > > > > > > > > > >> DELETE_STARTED, DELETE_FINISHED?
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >> 610.
> > remote.log.reader.max.pending.tasks:
> > > > > > "Maximum
> > > > > > > > > remote
> > > > > > > > > > > log
> > > > > > > > > > > > > > > reader
> > > > > > > > > > > > > > > > > > >> thread pool task queue size. If the task
> > > > queue
> > > > > > is
> > > > > > > > > full,
> > > > > > > > > > > broker
> > > > > > > > > > > > > > > will stop
> > > > > > > > > > > > > > > > > > >> reading remote log segments." What does
> > the
> > > > > > > broker do
> > > > > > > > > if
> > > > > > > > > > > the
> > > > > > > > > > > > > > > queue is
> > > > > > > > > > > > > > > > > > >> full?
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >> 611. What do we return if the request
> > > > > > offset/epoch
> > > > > > > > > > > doesn't exist
> > > > > > > > > > > > > > > in the
> > > > > > > > > > > > > > > > > > >> following API?
> > > > > > > > > > > > > > > > > > >> RemoteLogSegmentMetadata
> > > > > > > > > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > > > > > > > > > > >> topicPartition, long offset, int
> > > > epochForOffset)
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >> Jun
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >> On Mon, Aug 31, 2020 at 11:19 AM Satish
> > > > Duggana
> > > > > > <
> > > > > > > > > satish.
> > > > > > > > > > > > > > duggana@
> > > > > > > > > > > > > > > > > > gmail. com
> > > > > > > > > > > > > > > > > > >> ( satish.duggana@gmail.com ) > wrote:
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>> KIP is updated with
> > > > > > > > > > > > > > > > > > >>> - Remote log segment metadata topic
> > message
> > > > > > > > > > > format/schema.
> > > > > > > > > > > > > > > > > > >>> - Added remote log segment metadata
> > state
> > > > > > > > > transitions and
> > > > > > > > > > > > > > > explained how
> > > > > > > > > > > > > > > > > > >>> the deletion of segments is handled,
> > > > including
> > > > > > > the
> > > > > > > > > case
> > > > > > > > > > > of
> > > > > > > > > > > > > > > partition
> > > > > > > > > > > > > > > > > > >>> deletions.
> > > > > > > > > > > > > > > > > > >>> - Added a few more limitations in the
> > "Non
> > > > > > goals"
> > > > > > > > > > > section.
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>> Thanks,
> > > > > > > > > > > > > > > > > > >>> Satish.
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>> On Thu, Aug 27, 2020 at 12:42 AM
> > Harsha Ch
> > > > <
> > > > > > > harsha.
> > > > > > > > > ch@
> > > > > > > > > > > > > > gmail.
> > > > > > > > > > > > > > > com (
> > > > > > > > > > > > > > > > > > >>> harsha.ch@gmail.com ) > wrote:
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>> Updated the KIP with Meeting Notes
> > section
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>> https:/ / cwiki. apache. org/
> > confluence/
> > > > > > > display/
> > > > > > > > > KAFKA/
> > > > > > > > > > > > > > > > > > KIP-405 <
> > > > > > > https://issues.apache.org/jira/browse/KIP-405>
> > > > > > > > > > > > > > >
> > > > > > > %3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> > > > > > > > > > > > > > > > > > >>> (
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > >
> > > >
> > https://cwiki.apache.org/confluence/display/KAFKA/KIP-405%3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> > > > > > > > > > > > > > > > > > >>> )
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>> On Tue, Aug 25, 2020 at 1:03 PM Jun
> > Rao <
> > > > jun@
> > > > > > > > > > > confluent. io
> > > > > > > > > > > > > > (
> > > > > > > > > > > > > > > > > > >>>> jun@confluent.io ) > wrote:
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>> Hi, Harsha,
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>> Thanks for the summary. Could you
> > add the
> > > > > > > summary
> > > > > > > > > and
> > > > > > > > > > > the
> > > > > > > > > > > > > > > recording
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>> link to
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>> the last section of
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>> https:/ / cwiki. apache. org/
> > confluence/
> > > > > > > display/
> > > > > > > > > KAFKA/
> > > > > > > > > > > > > > > > > > Kafka+Improvement+Proposals
> > > > > > > > > > > > > > > > > > >>> (
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > >
> > > >
> > https://cwiki.apache.org/confluence/display/KAFKA/Kafka+Improvement+Proposals
> > > > > > > > > > > > > > > > > > >>> )
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>> ?
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>> Jun
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>> On Tue, Aug 25, 2020 at 11:12 AM
> > Harsha
> > > > > > > > > Chintalapani <
> > > > > > > > > > > kafka@
> > > > > > > > > > > > > > > > > > harsha. io (
> > > > > > > > > > > > > > > > > > >>>>> kafka@harsha.io ) > wrote:
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>> Thanks everyone for attending the
> > > > meeting
> > > > > > > today.
> > > > > > > > > > > > > > > > > > >>>>>> Here is the recording
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>> https:/ / drive. google. com/ file/ d/
> > > > > > > > > > > > > > > > > > 14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/
> > > > view?usp=sharing
> > > > > > > > > > > > > > > > > > >>> (
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > >
> > > >
> > https://drive.google.com/file/d/14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/view?usp=sharing
> > > > > > > > > > > > > > > > > > >>> )
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>> Notes:
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>> 1. KIP is updated with follower
> > fetch
> > > > > > > protocol and
> > > > > > > > > > > ready to
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>> reviewed
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>> 2. Satish to capture schema of
> > internal
> > > > > > > metadata
> > > > > > > > > > > topic in
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > KIP
> > > > > > > > > > > > > > > > > > >>>>>> 3. We will update the KIP with
> > details
> > > > of
> > > > > > > > > different
> > > > > > > > > > > cases
> > > > > > > > > > > > > > > > > > >>>>>> 4. Test plan will be captured in a
> > doc
> > > > and
> > > > > > > will
> > > > > > > > > add
> > > > > > > > > > > to the
> > > > > > > > > > > > > > KIP
> > > > > > > > > > > > > > > > > > >>>>>> 5. Add a section "Limitations" to
> > > > capture
> > > > > > the
> > > > > > > > > > > capabilities
> > > > > > > > > > > > > > > that
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>> will
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>> be
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>> introduced with this KIP and what
> > will
> > > > not
> > > > > > be
> > > > > > > > > covered
> > > > > > > > > > > in
> > > > > > > > > > > > > > this
> > > > > > > > > > > > > > > KIP.
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>> Please add to it I missed anything.
> > Will
> > > > > > > produce a
> > > > > > > > > > > formal
> > > > > > > > > > > > > > > meeting
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>> notes
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>> from next meeting onwards.
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>> Thanks,
> > > > > > > > > > > > > > > > > > >>>>>> Harsha
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>> On Mon, Aug 24, 2020 at 9:42 PM,
> > Ying
> > > > Zheng
> > > > > > <
> > > > > > > > > yingz@
> > > > > > > > > > > uber.
> > > > > > > > > > > > > > > com.
> > > > > > > > > > > > > > > > > > invalid (
> > > > > > > > > > > > > > > > > > >>>>>> yingz@uber.com.invalid ) > wrote:
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> We did some basic feature tests at
> > > > Uber.
> > > > > > The
> > > > > > > test
> > > > > > > > > > > cases and
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
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> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
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> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>> results are
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>>
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> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> shared in this google doc:
> > > > > > > > > > > > > > > > > > >>>>>>> https:/ / docs. google. com/
> > > > spreadsheets/
> > > > > > > d/ (
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > https://docs.google.com/spreadsheets/d/ )
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >
> > > > > > 1XhNJqjzwXvMCcAOhEH0sSXU6RTvyoSf93DHF-YMfGLk/edit?usp=sharing
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> The performance test results were
> > > > already
> > > > > > > shared
> > > > > > > > > in
> > > > > > > > > > > the KIP
> > > > > > > > > > > > > > > last
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
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> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>> month.
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> On Mon, Aug 24, 2020 at 11:10 AM
> > > > Harsha Ch
> > > > > > <
> > > > > > > > > harsha.
> > > > > > > > > > > ch@
> > > > > > > > > > > > > > > gmail.
> > > > > > > > > > > > > > > > > > com (
> > > > > > > > > > > > > > > > > > >>>>>>> harsha.ch@gmail.com ) >
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>> wrote:
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> "Understand commitments towards
> > driving
> > > > > > > design &
> > > > > > > > > > > > > > > implementation of
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>
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> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>> the
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>> KIP
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> further and how it aligns with
> > > > participant
> > > > > > > > > interests
> > > > > > > > > > > in
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>> contributing to
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>> the
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> efforts (ex: in the context of
> > Uber’s
> > > > Q3/Q4
> > > > > > > > > > > roadmap)." What
> > > > > > > > > > > > > > > is that
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>> about?
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> On Mon, Aug 24, 2020 at 11:05 AM
> > > > Kowshik
> > > > > > > > > Prakasam <
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>> kprakasam@ confluent. io (
> > > > > > > kprakasam@confluent.io
> > > > > > > > > ) >
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> wrote:
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> Hi Harsha,
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> The following google doc contains a
> > > > > > proposal
> > > > > > > for
> > > > > > > > > > > temporary
> > > > > > > > > > > > > > > agenda
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>> for
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>> the
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> KIP-405 <
> > > > > > > > > > > https://issues.apache.org/jira/browse/KIP-405> <
> > > > > > > > > > > > > > > https:/ / issues. apache. org/ jira/ browse/
> > KIP-405
> > > > > > > > > > > > > > > <https://issues.apache.org/jira/browse/KIP-405>
> > (
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > https://issues.apache.org/jira/browse/KIP-405 )
> > > > > > > > > >
> > > > > > > > > > > sync
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>> meeting
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> tomorrow:
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> https:/ / docs. google. com/
> > document/
> > > > d/ (
> > > > > > > > > > > > > > > > > > >>>>>>>
> > https://docs.google.com/document/d/ )
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > 1pqo8X5LU8TpwfC_iqSuVPezhfCfhGkbGN2TqiPA3LBU/edit
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> .
> > > > > > > > > > > > > > > > > > >>>>>>> Please could you add it to the
> > Google
> > > > > > > calendar
> > > > > > > > > > > invite?
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> Thank you.
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> Cheers,
> > > > > > > > > > > > > > > > > > >>>>>>> Kowshik
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> On Thu, Aug 20, 2020 at 10:58 AM
> > > > Harsha Ch
> > > > > > <
> > > > > > > > > harsha.
> > > > > > > > > > > ch@
> > > > > > > > > > > > > > > gmail.
> > > > > > > > > > > > > > > > > > com (
> > > > > > > > > > > > > > > > > > >>>>>>> harsha.ch@gmail.com ) >
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>> wrote:
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> Hi All,
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> Scheduled a meeting for Tuesday
> > 9am -
> > > > 10am.
> > > > > > > I can
> > > > > > > > > > > record
> > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>
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> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>> upload for
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> community to be able to follow the
> > > > > > > discussion.
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> Jun, please add the required folks
> > on
> > > > > > > confluent
> > > > > > > > > side.
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> Thanks,
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> Harsha
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> On Thu, Aug 20, 2020 at 12:33 AM,
> > > > Alexandre
> > > > > > > > > Dupriez <
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>> alexandre.dupriez@
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> gmail. com ( http://gmail.com/ ) >
> > > > wrote:
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> Hi Jun,
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> Many thanks for your initiative.
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> If you like, I am happy to attend
> > at
> > > > the
> > > > > > > time you
> > > > > > > > > > > > > > suggested.
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> Many thanks,
> > > > > > > > > > > > > > > > > > >>>>>>> Alexandre
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> Le mer. 19 août 2020 à 22:00,
> > Harsha
> > > > Ch <
> > > > > > > > > harsha. ch@
> > > > > > > > > > > > > > > gmail. com (
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>> harsha.
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> ch@ gmail. com ( ch@gmail.com ) )
> > > a
> > > > > > écrit
> > > > > > > :
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> Hi Jun,
> > > > > > > > > > > > > > > > > > >>>>>>> Thanks. This will help a lot.
> > Tuesday
> > > > will
> > > > > > > work
> > > > > > > > > for
> > > > > > > > > > > us.
> > > > > > > > > > > > > > > > > > >>>>>>> -Harsha
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> On Wed, Aug 19, 2020 at 1:24 PM Jun
> > > > Rao <
> > > > > > > jun@
> > > > > > > > > > > confluent.
> > > > > > > > > > > > > > > io (
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>> jun@
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> confluent. io (
> > http://confluent.io/
> > > > ) ) >
> > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> Hi, Satish, Ying, Harsha,
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> Do you think it would be useful to
> > > > have a
> > > > > > > regular
> > > > > > > > > > > virtual
> > > > > > > > > > > > > > > meeting
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>> to
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> discuss this KIP? The goal of the
> > > > meeting
> > > > > > > will be
> > > > > > > > > > > sharing
> > > > > > > > > > > > > > > > > > >>>>>>> design/development progress and
> > > > discussing
> > > > > > > any
> > > > > > > > > open
> > > > > > > > > > > issues
> > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> accelerate
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> this KIP. If so, will every Tuesday
> > > > (from
> > > > > > > next
> > > > > > > > > week)
> > > > > > > > > > > > > > 9am-10am
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> PT
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> work for you? I can help set up a
> > Zoom
> > > > > > > meeting,
> > > > > > > > > > > invite
> > > > > > > > > > > > > > > everyone who
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> might
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> be interested, have it recorded and
> > > > shared,
> > > > > > > etc.
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> Thanks,
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> Jun
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> On Tue, Aug 18, 2020 at 11:01 AM
> > Satish
> > > > > > > Duggana <
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> satish. duggana@ gmail. com (
> > satish.
> > > > > > > duggana@
> > > > > > > > > > > gmail. com
> > > > > > > > > > > > > > (
> > > > > > > > > > > > > > > > > > >>>>>>> satish.duggana@gmail.com ) ) >
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> wrote:
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> Hi Kowshik,
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> Thanks for looking into the KIP and
> > > > sending
> > > > > > > your
> > > > > > > > > > > comments.
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > > >>>>>>> 5001. Under the section "Follower
> > fetch
> > > > > > > protocol
> > > > > > > > > in
> > > > > > > > > > > > > > detail",
> > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > >>>>>>> next-local-offset is the offset
> > upto
> > > > which
> > > > > > > the
> > > > > > > > > > > segments are
> > > > > > > > > > > > > > > copied
> > > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > >
> > > > > > >
> > > > > >
> > > >
> >

Re: [DISCUSS] KIP-405: Kafka Tiered Storage

[Jun Rao <ju...@confluent.io>]

Hi, Satish,

Thanks for the reply. A few more comments below.

6000. When RSM/RLMM is not available, it seems that we need to return a
retriable error to the affected client requests. So, should we add a new
error code for requests like fetch and listOffset?

9111. RemotePartitionRemover:
91111.1 Could we make it clear that it's part of the default RLMM
implementation and a separate implementation is needed if one has a
customized RLMM?
91111.2 "RPRM gets all the remote log segments for the partition using RLMM
and each of these remote log segments is deleted with the next steps.RLMM
subscribes to the local remote log metadata partitions and it will have the
segment metadata of all the user topic partitions associated with that
remote log metadata partition." It seems that RLMM needs to subscribe to
the remote log metadata partitions first before those segments can be
deleted?
9111.3 There are still references to "remote log cleaners". They need to be
replaced with RemotePartitionRemover.

9114.1 Could we add the requirement on log.message.format before enabling
tiered storage?

9116. RemoteLogMetadataFormatter: This is used with the ConsoleConsumer
tool, right? Then, are those new options for ConsoleConsumer and how are
they passed in?

Thanks,

Jun


On Mon, Jan 25, 2021 at 8:02 AM Satish Duggana <sa...@gmail.com>
wrote:

> Hi Jun,
>
> Thanks for your comments. Please find the inline replies below.
> Several of these were discussed/clarified in our last discussion.
>
> 6000. Since we are returning new error codes, we need to bump up the
> protocol version for Fetch request. Also, it will be useful to document all
> new error codes and whether they are retriable or not.
> This previous comment doesn't seem to be addressed.
>
> Updated KIP on fetch protocol and error code.
>
> 9110. flat_file_format: Could you define the serialized representation for
> each field in the header?
>
> Added the serialized representation types in the KIP.
>
> 9111. RPM has the following 2 steps.
> "1. The controller publishes delete_partition_marked event to say that the
> partition is marked for deletion. There can be multiple events published
> when the controller restarts or failover and this event will be
> deduplicated by RPM.
> 2. RPM receives the delete_partition_marked and processes it if it is not
> yet processed earlier."
> What triggers RPM to read __remote_log_metadata? Is RPM part of the default
> RLMM implementation or is it meant for any RLMM implementation?
>
> RPM(or RPRM) is only for the default RLMM implementation. RPM receives
> the delete_partition_marked events from RLMM and acts on them. Updated
> KIP with more details.
>
> 9112. remote.log.manager.task.retry.backoff.ms: It would be useful to make
> it clear in the comment that this is for the initial retry backoff.
>
> Updated the KIP.
>
> 9113. RLMM:
> 9113.1 updateRemoteLogSegmentMetadata(): This comment needs to be updated.
>
> Updated javadoc of this method.
>
> 9113.2 Should RemoteLogSegmentMetadataUpdate include a leadeEpoch field
> since all other update events have leaderEpoch?
>
> +1 to have that,  updated the KIP.
>
> 9113.3 Could we rename RemotePartitionState to RemotePartitionDeleteState
> to make it clear this is for deletion?
>
> Sure, updated the KIP.
>
> 9113.4 Could we rename RemoteLogState to RemoteLogSegmentState to make it
> clear this is for segment?
>
> Sure, Updated the KIP.
>
> 9114.Upgrade:
> 9114.1 It seems that we require message format > 0.11 for turning on the
> remote store feature.
>
> 9114.2 It's not clear to me why remote.log.storage.system.enable needs to
> be set to true before bumping up inter.broker.protocol.version.
>
> Agree that based on our discussion, this is not required. Upgrade
> notes is updated.
>
> 9114.3 "If the topic-id is not received in the LeaderAndIsr request then
> remote log storage will not start. But it will log an error message in the
> log. One way to address this is to do a rolling restart of that broker, so
> that the leader will be moved to another broker and the controller will
> send LeaderAndIsr with the registered topic-id." Why is this needed? With
> KIP-516, after upgrading to the latest protocol, topicIds are auto created.
>
> I thought there may be edge cases of not receiving topic-id but you
> clarified in the meeting that won’t be the case. I agree that it is
> not needed.
>
> 9115. testing: Could you comment on how we plan to do integration and
> system tests? Do we plan to include, for example, an in-memory
> implementation of RSM?
>
> For integration tests, we can have file based RSM that we have. For
> system tests, we can have a single node HDFS cluster in one of the
> containers and use HDFS RSM implementation.
>
> 9116. There is still a todo for the message formatter.
>
> Updated the KIP with the format.
>
>
> Satish.
>
>
> On Tue, 12 Jan 2021 at 07:07, Jun Rao <ju...@confluent.io> wrote:
> >
> > Hi, Satish,
> >
> > Thanks for the reply. A few more followup comments.
> >
> > 6000. Since we are returning new error codes, we need to bump up the
> > protocol version for Fetch request. Also, it will be useful to document
> all
> > new error codes and whether they are retriable or not.
> > This previous comment doesn't seem to be addressed.
> >
> > 9110. flat_file_format: Could you define the serialized representation
> for
> > each field in the header?
> >
> > 9111. RPM has the following 2 steps.
> > "1. The controller publishes delete_partition_marked event to say that
> the
> > partition is marked for deletion. There can be multiple events published
> > when the controller restarts or failover and this event will be
> > deduplicated by RPM.
> > 2. RPM receives the delete_partition_marked and processes it if it is not
> > yet processed earlier."
> > What triggers RPM to read __remote_log_metadata? Is RPM part of the
> default
> > RLMM implementation or is it meant for any RLMM implementation?
> >
> > 9112. remote.log.manager.task.retry.backoff.ms: It would be useful to
> make
> > it clear in the comment that this is for the initial retry backoff.
> >
> > 9113. RLMM:
> > 9113.1 updateRemoteLogSegmentMetadata(): This comment needs to be
> updated.
> > 9113.2 Should RemoteLogSegmentMetadataUpdate include a leadeEpoch field
> > since all other update events have leaderEpoch?
> > 9113.3 Could we rename RemotePartitionState to RemotePartitionDeleteState
> > to make it clear this is for deletion?
> > 9113.4 Could we rename RemoteLogState to RemoteLogSegmentState to make it
> > clear this is for segment?
> >
> > 9114.Upgrade:
> > 9114.1 It seems that we require message format > 0.11 for turning on the
> > remote store feature.
> > 9114.2 It's not clear to me why remote.log.storage.system.enable needs to
> > be set to true before bumping up inter.broker.protocol.version.
> > 9114.3 "If the topic-id is not received in the LeaderAndIsr request then
> > remote log storage will not start. But it will log an error message in
> the
> > log. One way to address this is to do a rolling restart of that broker,
> so
> > that the leader will be moved to another broker and the controller will
> > send LeaderAndIsr with the registered topic-id." Why is this needed? With
> > KIP-516, after upgrading to the latest protocol, topicIds are auto
> created.
> >
> > 9115. testing: Could you comment on how we plan to do integration and
> > system tests? Do we plan to include, for example, an in-memory
> > implementation of RSM?
> >
> > 9116. There is still a todo for the message formatter.
> >
> > Jun
> >
> > On Sat, Jan 9, 2021 at 2:04 AM Satish Duggana <sa...@gmail.com>
> > wrote:
> >
> > > Hi Jun,
> > > Thanks for your comments. Please find the inline replies below.
> > >
> > > 6022. For packages used for server plugins, the convention is to
> > > use org.apache.kafka.server. See java-based Authorizer as an example.
> > >
> > > Sure, ‘org.apache.kafka.common.log.remote.storage’ renamed to
> > > ‘org.apache.kafka.server.log.remote.storage’.  Updated in the KIP.
> > >
> > > 9100. Do we need DeletePartitionStateRecord in flat_file_format? The
> flat
> > > file captures the state of the remote segments. After a partition is
> > > deleted, it seems that we just need to remove the partitions's remote
> > > segments from the flat file.
> > >
> > > DeletePartitionState might not yet have been processed by RPM and not
> > > completed. We  will not have  that in flat  file format  once it
> > > reaches DELETE_PARTITION_FINISHED state.
> > >
> > > 9101. Upgrade: It will be useful to allow direct upgrade from an old
> > > version. It seems that's doable. One can just do the normal upgrade
> first
> > > and wait enough time (for producer snapshots to be built), and then
> enable
> > > remote storage.
> > >
> > > Upgrade notes updates in the KIP.
> > >
> > > 9102. RemotePartitionRemover(RPM) process: Is it true that RPM starts
> > > tracking the remote segments when RLMM.onPartitionLeadershipChanges()
> is
> > > called with the broker being the leader for __remote_log_metadata
> > > partition? If so, could we document it?
> > >
> > > The current plan is to have that as part of RLMM and RPM uses that to
> > > get the remote segments list. I will add this detail in the respective
> > > sections.
> > >
> > > Satish.
> > >
> > > On Wed, 16 Dec 2020 at 23:55, Jun Rao <ju...@confluent.io> wrote:
> > > >
> > > > Hi, Satish,
> > > >
> > > > Thanks for the reply. A few more followup comments.
> > > >
> > > > 6022. For packages used for server plugins, the convention is to
> > > > use org.apache.kafka.server. See java-based Authorizer as an example.
> > > >
> > > > 9100. Do we need DeletePartitionStateRecord in flat_file_format? The
> flat
> > > > file captures the state of the remote segments. After a partition is
> > > > deleted, it seems that we just need to remove the partitions's remote
> > > > segments from the flat file.
> > > >
> > > > 9101. Upgrade: It will be useful to allow direct upgrade from an old
> > > > version. It seems that's doable. One can just do the normal upgrade
> first
> > > > and wait enough time (for producer snapshots to be built), and then
> > > enable
> > > > remote storage.
> > > >
> > > > 9102. RemotePartitionRemover(RPM) process: Is it true that RPM starts
> > > > tracking the remote segments when
> RLMM.onPartitionLeadershipChanges() is
> > > > called with the broker being the leader for __remote_log_metadata
> > > > partition? If so, could we document it?
> > > >
> > > > Jun
> > > >
> > > > On Tue, Dec 15, 2020 at 8:47 AM Kowshik Prakasam <
> kprakasam@confluent.io
> > > >
> > > > wrote:
> > > >
> > > > > Hi Satish,
> > > > >
> > > > > Thanks for the updates! A few more comments below.
> > > > >
> > > > > 9001. Under the "Upgrade" section, there is a line mentioning:
> > > "Upgrade the
> > > > > existing Kafka cluster to 2.7 version and allow this to run for
> the log
> > > > > retention of user topics that you want to enable tiered storage.
> This
> > > will
> > > > > allow all the topics to have the producer snapshots generated for
> each
> > > log
> > > > > segment." -- Which associated change in AK were you referring to
> here?
> > > Is
> > > > > it: https://github.com/apache/kafka/pull/7929 ? It seems like I
> don't
> > > see
> > > > > it in the 2.7 release branch yet, here is the link:
> > > > > https://github.com/apache/kafka/commits/2.7.
> > > > >
> > > > > 9002. Under the "Upgrade" section, the configuration mentioned is
> > > > > 'remote.log.storage.system.enable'. However, under "Public
> Interfaces"
> > > > > section the corresponding configuration is
> > > 'remote.storage.system.enable'.
> > > > > Could we use the same one in both, maybe
> > > > > 'remote.log.storage.system.enable'?
> > > > >
> > > > > 9003. Under "Per Topic Configuration", the KIP recommends setting
> > > > > 'remote.log.storage.enable' to true at a per-topic level. It will
> be
> > > useful
> > > > > to add a line that if the user wants to enable it for all topics,
> then
> > > they
> > > > > should be able to set the cluster-wide default to true. Also, it
> will
> > > be
> > > > > useful to mention that the KIP currently does not support setting
> it to
> > > > > false (after it is set to true), and add that to the future work
> > > section.
> > > > >
> > > > > 9004. Under "Committed offsets file format", the sample provided
> shows
> > > > > partition number and offset. Is the topic name required for
> identifying
> > > > > which topic the partitions belong to?
> > > > >
> > > > > 9005. Under "Internal flat-file store format of remote log
> metadata",
> > > it
> > > > > seems useful to specify both topic name and topic ID for debugging
> > > > > purposes.
> > > > >
> > > > > 9006. Under "Internal flat-file store format of remote log
> metadata",
> > > the
> > > > > description of "metadata-topic-offset" currently says "offset of
> the
> > > remote
> > > > > log metadata topic from which this topic partition's remote log
> > > metadata is
> > > > > fetched." Just for the wording, perhaps you meant to refer to the
> > > offset
> > > > > upto which the file has been committed? i.e. "offset of the remote
> log
> > > > > metadata topic upto which this topic partition's remote log
> metadata
> > > has
> > > > > been committed into this file."
> > > > >
> > > > > 9007. Under "Internal flat-file store format of remote log
> metadata",
> > > the
> > > > > schema of the payload (i.e. beyond the header) seems to contain the
> > > events
> > > > > from the metadata topic. It seems useful to instead persist the
> > > > > representation of the materialized state of the events, so that
> for the
> > > > > same segment only the latest state is stored. Besides reducing
> storage
> > > > > footprint, this also is likely to relate directly with the
> in-memory
> > > > > representation of the RLMM cache (which probably is some kind of a
> Map
> > > with
> > > > > key being segment ID and value being the segment state), so
> recovery
> > > from
> > > > > disk will be straightforward.
> > > > >
> > > > > 9008. Under "Topic deletion lifecycle", step (1), it will be
> useful to
> > > > > mention when in the deletion flow does the controller publish the
> > > > > delete_partition_marked event to say that the partition is marked
> for
> > > > > deletion?
> > > > >
> > > > > 9009. There are ~4 TODOs in the KIP. Could you please address
> these or
> > > > > remove them?
> > > > >
> > > > > 9010. There is a reference to a Google doc on the KIP which was
> used
> > > > > earlier for discussions. Please could you remove the reference,
> since
> > > the
> > > > > KIP is the source of the truth?
> > > > >
> > > > > 9011. This feedback is from an earlier comment. In the
> > > RemoteStorageManager
> > > > > interface, there is an API defined for each file type. For example,
> > > > > fetchOffsetIndex, fetchTimestampIndex etc. To avoid the
> duplication,
> > > I'd
> > > > > suggest we can instead have a FileType enum and a common get API
> based
> > > on
> > > > > the FileType. What do you think?
> > > > >
> > > > >
> > > > > Cheers,
> > > > > Kowshik
> > > > >
> > > > >
> > > > > On Mon, Dec 14, 2020 at 11:07 AM Satish Duggana <
> > > satish.duggana@gmail.com>
> > > > > wrote:
> > > > >
> > > > > > Hi Jun,
> > > > > > Thanks for your comments. Please go through the inline replies.
> > > > > >
> > > > > >
> > > > > > 5102.2: It seems that both positions can just be int. Another
> option
> > > is
> > > > > to
> > > > > > have two methods. Would it be clearer?
> > > > > >
> > > > > >     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> > > > > > remoteLogSegmentMetadata,  int startPosition)
> > > > > throwsRemoteStorageException;
> > > > > >
> > > > > >     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> > > > > > remoteLogSegmentMetadata, int startPosition, int endPosition)
> throws
> > > > > > RemoteStorageException;
> > > > > >
> > > > > > That makes sense to me, updated the KIP.
> > > > > >
> > > > > > 6003: Could you also update the javadoc for the return value?
> > > > > >
> > > > > > Updated.
> > > > > >
> > > > > > 6020: local.log.retention.bytes: Should it default to
> > > log.retention.bytes
> > > > > > to be consistent with local.log.retention.ms?
> > > > > >
> > > > > > Yes, it can be defaulted to log.retention.bytes.
> > > > > >
> > > > > > 6021: Could you define TopicIdPartition?
> > > > > >
> > > > > > Added TopicIdPartition in the KIP.
> > > > > >
> > > > > > 6022: For all public facing classes, could you specify the
> package
> > > name?
> > > > > >
> > > > > > Updated.
> > > > > >
> > > > > >
> > > > > > Thanks,
> > > > > > Satish.
> > > > > >
> > > > > > On Tue, Dec 8, 2020 at 12:59 AM Jun Rao <ju...@confluent.io>
> wrote:
> > > > > > >
> > > > > > > Hi, Satish,
> > > > > > >
> > > > > > > Thanks for the reply. A few more comments below.
> > > > > > >
> > > > > > > 5102.2: It seems that both positions can just be int. Another
> > > option is
> > > > > > to
> > > > > > > have two methods. Would it be clearer?
> > > > > > >
> > > > > > >     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> > > > > > > remoteLogSegmentMetadata,
> > > > > > >                                     int startPosition) throws
> > > > > > > RemoteStorageException;
> > > > > > >
> > > > > > >     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> > > > > > > remoteLogSegmentMetadata,
> > > > > > >                                     int startPosition, int
> > > endPosition)
> > > > > > > throws RemoteStorageException;
> > > > > > >
> > > > > > > 6003: Could you also update the javadoc for the return value?
> > > > > > >
> > > > > > > 6010: What kind of tiering throughput have you seen with 5
> threads?
> > > > > > >
> > > > > > > 6020: local.log.retention.bytes: Should it default to
> > > > > log.retention.bytes
> > > > > > > to be consistent with local.log.retention.ms?
> > > > > > >
> > > > > > > 6021: Could you define TopicIdPartition?
> > > > > > >
> > > > > > > 6022: For all public facing classes, could you specify the
> package
> > > > > name?
> > > > > > >
> > > > > > > It seems that you already added the topicId support. Two other
> > > > > remaining
> > > > > > > items are (a) the format of local tier metadata storage and (b)
> > > > > upgrade.
> > > > > > >
> > > > > > > Jun
> > > > > > >
> > > > > > > On Mon, Dec 7, 2020 at 8:56 AM Satish Duggana <
> > > > > satish.duggana@gmail.com>
> > > > > > > wrote:
> > > > > > >
> > > > > > > > Hi Jun,
> > > > > > > > Thanks for your comments. Please find the inline replies
> below.
> > > > > > > >
> > > > > > > > >605.2 It's rare for the follower to need the remote data.
> So,
> > > the
> > > > > > current
> > > > > > > > approach is fine too. Could you document the process of
> > > rebuilding
> > > > > the
> > > > > > > > producer state since we can't simply trim the producerState
> to an
> > > > > > offset in
> > > > > > > > the middle of a segment.
> > > > > > > >
> > > > > > > > Will clarify in the KIP.
> > > > > > > >
> > > > > > > > >5102.2 Would it be clearer to make startPosiont long and
> > > endPosition
> > > > > > of
> > > > > > > > Optional<Long>?
> > > > > > > >
> > > > > > > > We will have arg checks with respective validation. It is
> not a
> > > good
> > > > > > > > practice to have arguments with optional as mentioned here.
> > > > > > > > https://rules.sonarsource.com/java/RSPEC-3553
> > > > > > > >
> > > > > > > >
> > > > > > > > >5102.5 LogSegmentData still has leaderEpochIndex as File
> > > instead of
> > > > > > > > ByteBuffer.
> > > > > > > >
> > > > > > > > Updated.
> > > > > > > >
> > > > > > > > >5102.7 Could you define all public methods for
> LogSegmentData?
> > > > > > > >
> > > > > > > > Updated.
> > > > > > > >
> > > > > > > > >5103.5 Could you change the reference to
> > > rlm_process_interval_ms and
> > > > > > > > rlm_retry_interval_ms to the new config names? Also, the
> retry
> > > > > interval
> > > > > > > > config seems still missing. It would be useful to support
> > > exponential
> > > > > > > > backoff with the retry interval config.
> > > > > > > >
> > > > > > > > Good point. We wanted the retry with truncated exponential
> > > backoff,
> > > > > > > > updated the KIP.
> > > > > > > >
> > > > > > > > >5111. "RLM follower fetches the earliest offset for the
> earliest
> > > > > > leader
> > > > > > > > epoch by calling RLMM.earliestLogOffset(TopicPartition
> > > > > topicPartition,
> > > > > > int
> > > > > > > > leaderEpoch) and updates that as the log start offset." This
> > > text is
> > > > > > still
> > > > > > > > there. Also, could we remove earliestLogOffset() from RLMM?
> > > > > > > >
> > > > > > > > Updated.
> > > > > > > >
> > > > > > > > >5115. There are still references to "remote log cleaners".
> > > > > > > >
> > > > > > > > Updated.
> > > > > > > >
> > > > > > > > >6000. Since we are returning new error codes, we need to
> bump
> > > up the
> > > > > > > > protocol version for Fetch request. Also, it will be useful
> to
> > > > > > document all
> > > > > > > > new error codes and whether they are retriable or not.
> > > > > > > >
> > > > > > > > Sure, we will add that in the KIP.
> > > > > > > >
> > > > > > > > >6001. public Map<Long, Long> segmentLeaderEpochs():
> Currently,
> > > > > > leaderEpoch
> > > > > > > > is int32 instead of long.
> > > > > > > >
> > > > > > > > Updated.
> > > > > > > >
> > > > > > > > >6002. Is RemoteLogSegmentMetadata.markedForDeletion() needed
> > > given
> > > > > > > > RemoteLogSegmentMetadata.state()?
> > > > > > > >
> > > > > > > > No, it is fixed.
> > > > > > > >
> > > > > > > > >6003. RemoteLogSegmentMetadata
> > > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > topicPartition, long offset, int epochForOffset): Should this
> > > return
> > > > > > > > Optional<RemoteLogSegmentMetadata>?
> > > > > > > >
> > > > > > > > That makes sense, updated.
> > > > > > > >
> > > > > > > > >6005. RemoteLogState: It seems it's better to split it
> between
> > > > > > > > DeletePartitionUpdate and RemoteLogSegmentMetadataUpdate
> since
> > > the
> > > > > > states
> > > > > > > > are never shared between the two use cases.
> > > > > > > >
> > > > > > > > Agree with that, updated.
> > > > > > > >
> > > > > > > > >6006. RLMM.onPartitionLeadershipChanges(): This may be ok.
> > > However,
> > > > > > is it
> > > > > > > > ture that other than the metadata topic, RLMM just needs to
> know
> > > > > > whether
> > > > > > > > there is a replica assigned to this broker and doesn't need
> to
> > > know
> > > > > > whether
> > > > > > > > the replica is the leader or the follower?
> > > > > > > >
> > > > > > > > That may be true. If the implementation does not need that,
> it
> > > can
> > > > > > > > ignore the information in the callback.
> > > > > > > >
> > > > > > > > >6007: "Handle expired remote segments (leader and
> follower)":
> > > Why is
> > > > > > this
> > > > > > > > needed in both the leader and the follower?
> > > > > > > >
> > > > > > > > Updated.
> > > > > > > >
> > > > > > > > >6008.       "name": "SegmentSizeInBytes",
> > > > > > > >                 "type": "int64",
> > > > > > > > The segment size can just be int32.
> > > > > > > >
> > > > > > > > Updated.
> > > > > > > >
> > > > > > > > >6009. For the record format in the log, it seems that we
> need
> > > to add
> > > > > > > > record
> > > > > > > > type and record version before the serialized bytes. We can
> > > follow
> > > > > the
> > > > > > > > convention used in
> > > > > > > >
> > > > > > > >
> > > > > >
> > > > >
> > >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-631%3A+The+Quorum-based+Kafka+Controller#KIP631:TheQuorumbasedKafkaController-RecordFormats
> > > > > > > >
> > > > > > > > Yes, KIP already mentions that these are serialized before
> the
> > > > > payload
> > > > > > > > as below. We will mention explicitly that these two are
> written
> > > > > before
> > > > > > > > the data is written.
> > > > > > > >
> > > > > > > > RLMM instance on broker publishes the message to the topic
> with
> > > key
> > > > > as
> > > > > > > > null and value with the below format.
> > > > > > > >
> > > > > > > > type      : unsigned var int, represents the value type. This
> > > value
> > > > > is
> > > > > > > > 'apikey' as mentioned in the schema.
> > > > > > > > version : unsigned var int, the 'version' number of the type
> as
> > > > > > > > mentioned in the schema.
> > > > > > > > data      : record payload in kafka protocol message format.
> > > > > > > >
> > > > > > > >
> > > > > > > > >6010. remote.log.manager.thread.pool.size: The default
> value is
> > > 10.
> > > > > > This
> > > > > > > > might be too high when enabling the tiered feature for the
> first
> > > > > time.
> > > > > > > > Since there are lots of segments that need to be tiered
> > > initially, a
> > > > > > large
> > > > > > > > number of threads could overwhelm the broker.
> > > > > > > >
> > > > > > > > Is the default value 5 reasonable?
> > > > > > > >
> > > > > > > > 6011. "The number of milli seconds to keep the local log
> segment
> > > > > > before it
> > > > > > > > gets deleted. If not set, the value in
> `log.retention.minutes` is
> > > > > > used. If
> > > > > > > > set to -1, no time limit is applied." We should use
> > > log.retention.ms
> > > > > > > > instead of log.retention.minutes.
> > > > > > > > Nice typo catch. Updated the KIP.
> > > > > > > >
> > > > > > > > Thanks,
> > > > > > > > Satish.
> > > > > > > >
> > > > > > > > On Thu, Dec 3, 2020 at 8:03 AM Jun Rao <ju...@confluent.io>
> wrote:
> > > > > > > > >
> > > > > > > > > Hi, Satish,
> > > > > > > > >
> > > > > > > > > Thanks for the updated KIP. A few more comments below.
> > > > > > > > >
> > > > > > > > > 605.2 It's rare for the follower to need the remote data.
> So,
> > > the
> > > > > > current
> > > > > > > > > approach is fine too. Could you document the process of
> > > rebuilding
> > > > > > the
> > > > > > > > > producer state since we can't simply trim the
> producerState to
> > > an
> > > > > > offset
> > > > > > > > in
> > > > > > > > > the middle of a segment.
> > > > > > > > >
> > > > > > > > > 5102.2 Would it be clearer to make startPosiont long and
> > > > > endPosition
> > > > > > of
> > > > > > > > > Optional<Long>?
> > > > > > > > >
> > > > > > > > > 5102.5 LogSegmentData still has leaderEpochIndex as File
> > > instead of
> > > > > > > > > ByteBuffer.
> > > > > > > > >
> > > > > > > > > 5102.7 Could you define all public methods for
> LogSegmentData?
> > > > > > > > >
> > > > > > > > > 5103.5 Could you change the reference to
> > > rlm_process_interval_ms
> > > > > and
> > > > > > > > > rlm_retry_interval_ms to the new config names? Also, the
> retry
> > > > > > interval
> > > > > > > > > config seems still missing. It would be useful to support
> > > > > exponential
> > > > > > > > > backoff with the retry interval config.
> > > > > > > > >
> > > > > > > > > 5111. "RLM follower fetches the earliest offset for the
> > > earliest
> > > > > > leader
> > > > > > > > > epoch by calling RLMM.earliestLogOffset(TopicPartition
> > > > > > topicPartition,
> > > > > > > > int
> > > > > > > > > leaderEpoch) and updates that as the log start offset."
> This
> > > text
> > > > > is
> > > > > > > > still
> > > > > > > > > there. Also, could we remove earliestLogOffset() from RLMM?
> > > > > > > > >
> > > > > > > > > 5115. There are still references to "remote log cleaners".
> > > > > > > > >
> > > > > > > > > 6000. Since we are returning new error codes, we need to
> bump
> > > up
> > > > > the
> > > > > > > > > protocol version for Fetch request. Also, it will be
> useful to
> > > > > > document
> > > > > > > > all
> > > > > > > > > new error codes and whether they are retriable or not.
> > > > > > > > >
> > > > > > > > > 6001. public Map<Long, Long> segmentLeaderEpochs():
> Currently,
> > > > > > > > leaderEpoch
> > > > > > > > > is int32 instead of long.
> > > > > > > > >
> > > > > > > > > 6002. Is RemoteLogSegmentMetadata.markedForDeletion()
> needed
> > > given
> > > > > > > > > RemoteLogSegmentMetadata.state()?
> > > > > > > > >
> > > > > > > > > 6003. RemoteLogSegmentMetadata
> > > > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > topicPartition, long offset, int epochForOffset): Should
> this
> > > > > return
> > > > > > > > > Optional<RemoteLogSegmentMetadata>?
> > > > > > > > >
> > > > > > > > > 6004. DeletePartitionUpdate.epoch(): It would be useful to
> > > pick a
> > > > > > more
> > > > > > > > > indicative name so that people understand what epoch this
> is.
> > > > > > > > >
> > > > > > > > > 6005. RemoteLogState: It seems it's better to split it
> between
> > > > > > > > > DeletePartitionUpdate and RemoteLogSegmentMetadataUpdate
> since
> > > the
> > > > > > states
> > > > > > > > > are never shared between the two use cases.
> > > > > > > > >
> > > > > > > > > 6006. RLMM.onPartitionLeadershipChanges(): This may be ok.
> > > However,
> > > > > > is it
> > > > > > > > > ture that other than the metadata topic, RLMM just needs to
> > > know
> > > > > > whether
> > > > > > > > > there is a replica assigned to this broker and doesn't
> need to
> > > know
> > > > > > > > whether
> > > > > > > > > the replica is the leader or the follower?
> > > > > > > > >
> > > > > > > > > 6007: "Handle expired remote segments (leader and
> follower)":
> > > Why
> > > > > is
> > > > > > this
> > > > > > > > > needed in both the leader and the follower?
> > > > > > > > >
> > > > > > > > > 6008.       "name": "SegmentSizeInBytes",
> > > > > > > > >                 "type": "int64",
> > > > > > > > > The segment size can just be int32.
> > > > > > > > >
> > > > > > > > > 6009. For the record format in the log, it seems that we
> need
> > > to
> > > > > add
> > > > > > > > record
> > > > > > > > > type and record version before the serialized bytes. We can
> > > follow
> > > > > > the
> > > > > > > > > convention used in
> > > > > > > > >
> > > > > > > >
> > > > > >
> > > > >
> > >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-631%3A+The+Quorum-based+Kafka+Controller#KIP631:TheQuorumbasedKafkaController-RecordFormats
> > > > > > > > > .
> > > > > > > > >
> > > > > > > > > 6010. remote.log.manager.thread.pool.size: The default
> value
> > > is 10.
> > > > > > This
> > > > > > > > > might be too high when enabling the tiered feature for the
> > > first
> > > > > > time.
> > > > > > > > > Since there are lots of segments that need to be tiered
> > > initially,
> > > > > a
> > > > > > > > large
> > > > > > > > > number of threads could overwhelm the broker.
> > > > > > > > >
> > > > > > > > > 6011. "The number of milli seconds to keep the local log
> > > segment
> > > > > > before
> > > > > > > > it
> > > > > > > > > gets deleted. If not set, the value in
> `log.retention.minutes`
> > > is
> > > > > > used.
> > > > > > > > If
> > > > > > > > > set to -1, no time limit is applied." We should use
> > > > > log.retention.ms
> > > > > > > > > instead of log.retention.minutes.
> > > > > > > > >
> > > > > > > > > Jun
> > > > > > > > >
> > > > > > > > > On Tue, Dec 1, 2020 at 2:42 AM Satish Duggana <
> > > > > > satish.duggana@gmail.com>
> > > > > > > > > wrote:
> > > > > > > > >
> > > > > > > > > > Hi,
> > > > > > > > > > We updated the KIP with the points mentioned in the
> earlier
> > > mail
> > > > > > > > > > except for KIP-516 related changes. You can go through
> them
> > > and
> > > > > > let us
> > > > > > > > > > know if you have any comments. We will update the KIP
> with
> > > the
> > > > > > > > > > remaining todo items and KIP-516 related changes by end
> of
> > > this
> > > > > > > > > > week(5th Dec).
> > > > > > > > > >
> > > > > > > > > > Thanks,
> > > > > > > > > > Satish.
> > > > > > > > > >
> > > > > > > > > > On Tue, Nov 10, 2020 at 8:26 PM Satish Duggana <
> > > > > > > > satish.duggana@gmail.com>
> > > > > > > > > > wrote:
> > > > > > > > > > >
> > > > > > > > > > > Hi Jun,
> > > > > > > > > > > Thanks for your comments. Please find the inline
> replies
> > > below.
> > > > > > > > > > >
> > > > > > > > > > > 605.2 "Build the local leader epoch cache by cutting
> the
> > > leader
> > > > > > epoch
> > > > > > > > > > > sequence received from remote storage to [LSO, ELO]." I
> > > > > > mentioned an
> > > > > > > > > > issue
> > > > > > > > > > > earlier. Suppose the leader's local start offset is
> 100.
> > > The
> > > > > > follower
> > > > > > > > > > finds
> > > > > > > > > > > a remote segment covering offset range [80, 120). The
> > > > > > producerState
> > > > > > > > with
> > > > > > > > > > > this remote segment is up to offset 120. To trim the
> > > > > > producerState to
> > > > > > > > > > > offset 100 requires more work since one needs to
> download
> > > the
> > > > > > > > previous
> > > > > > > > > > > producerState up to offset 80 and then replay the
> messages
> > > from
> > > > > > 80 to
> > > > > > > > > > 100.
> > > > > > > > > > > It seems that it's simpler in this case for the
> follower
> > > just
> > > > > to
> > > > > > > > take the
> > > > > > > > > > > remote segment as it is and start fetching from offset
> 120.
> > > > > > > > > > >
> > > > > > > > > > > We chose that approach to avoid any edge cases here. It
> > > may be
> > > > > > > > > > > possible that the remote log segment that is received
> may
> > > not
> > > > > > have
> > > > > > > > the
> > > > > > > > > > > same leader epoch sequence from 100-120 as it contains
> on
> > > the
> > > > > > > > > > > leader(this can happen due to unclean leader). It is
> safe
> > > to
> > > > > > start
> > > > > > > > > > > from what the leader returns here.Another way is to
> find
> > > the
> > > > > > remote
> > > > > > > > > > > log segment
> > > > > > > > > > >
> > > > > > > > > > > 5016. Just to echo what Kowshik was saying. It seems
> that
> > > > > > > > > > > RLMM.onPartitionLeadershipChanges() is only called on
> the
> > > > > > replicas
> > > > > > > > for a
> > > > > > > > > > > partition, not on the replicas for the
> > > > > > __remote_log_segment_metadata
> > > > > > > > > > > partition. It's not clear how the leader of
> > > > > > > > __remote_log_segment_metadata
> > > > > > > > > > > obtains the metadata for remote segments for deletion.
> > > > > > > > > > >
> > > > > > > > > > > RLMM will always receive the callback for the remote
> log
> > > > > metadata
> > > > > > > > > > > topic partitions hosted on the local broker and these
> will
> > > be
> > > > > > > > > > > subscribed. I will make this clear in the KIP.
> > > > > > > > > > >
> > > > > > > > > > > 5100. KIP-516 has been accepted and is being
> implemented
> > > now.
> > > > > > Could
> > > > > > > > you
> > > > > > > > > > > update the KIP based on topicID?
> > > > > > > > > > >
> > > > > > > > > > > We mentioned KIP-516 and how it helps. We will update
> this
> > > KIP
> > > > > > with
> > > > > > > > > > > all the changes it brings with KIP-516.
> > > > > > > > > > >
> > > > > > > > > > > 5101. RLMM: It would be useful to clarify how the
> > > following two
> > > > > > APIs
> > > > > > > > are
> > > > > > > > > > > used. According to the wiki, the former is used for
> topic
> > > > > > deletion
> > > > > > > > and
> > > > > > > > > > the
> > > > > > > > > > > latter is used for retention. It seems that retention
> > > should
> > > > > use
> > > > > > the
> > > > > > > > > > former
> > > > > > > > > > > since remote segments without a matching epoch in the
> > > leader
> > > > > > > > (potentially
> > > > > > > > > > > due to unclean leader election) also need to be garbage
> > > > > > collected.
> > > > > > > > The
> > > > > > > > > > > latter seems to be used for the new leader to
> determine the
> > > > > last
> > > > > > > > tiered
> > > > > > > > > > > segment.
> > > > > > > > > > >     default Iterator<RemoteLogSegmentMetadata>
> > > > > > > > > > > listRemoteLogSegments(TopicPartition topicPartition)
> > > > > > > > > > >     Iterator<RemoteLogSegmentMetadata>
> > > > > > > > > > listRemoteLogSegments(TopicPartition
> > > > > > > > > > > topicPartition, long leaderEpoch);
> > > > > > > > > > >
> > > > > > > > > > > Right,.that is what we are currently doing. We will
> update
> > > the
> > > > > > > > > > > javadocs and wiki with that. Earlier, we did not want
> to
> > > remove
> > > > > > the
> > > > > > > > > > > segments which are not matched with leader epochs from
> the
> > > > > ladder
> > > > > > > > > > > partition as they may be used later by a replica which
> can
> > > > > > become a
> > > > > > > > > > > leader (unclean leader election) and refer those
> segments.
> > > But
> > > > > > that
> > > > > > > > > > > may leak these segments in remote storage until the
> topic
> > > > > > lifetime.
> > > > > > > > We
> > > > > > > > > > > decided to cleanup the segments with the oldest incase
> of
> > > size
> > > > > > based
> > > > > > > > > > > retention also.
> > > > > > > > > > >
> > > > > > > > > > > 5102. RSM:
> > > > > > > > > > > 5102.1 For methods like fetchLogSegmentData(), it seems
> > > that
> > > > > > they can
> > > > > > > > > > > use RemoteLogSegmentId instead of
> RemoteLogSegmentMetadata.
> > > > > > > > > > >
> > > > > > > > > > > It will be useful to have metadata for RSM to fetch log
> > > > > segment.
> > > > > > It
> > > > > > > > > > > may create location/path using id with other metadata
> too.
> > > > > > > > > > >
> > > > > > > > > > > 5102.2 In fetchLogSegmentData(), should we use long
> > > instead of
> > > > > > Long?
> > > > > > > > > > >
> > > > > > > > > > > Wanted to keep endPosition as optional to read till the
> > > end of
> > > > > > the
> > > > > > > > > > > segment and avoid sentinels.
> > > > > > > > > > >
> > > > > > > > > > > 5102.3 Why only some of the methods have default
> > > implementation
> > > > > > and
> > > > > > > > > > others
> > > > > > > > > > > Don't?
> > > > > > > > > > >
> > > > > > > > > > > Actually,  RSM will not have any default
> implementations.
> > > > > Those 3
> > > > > > > > > > > methods were made default earlier for tests etc.
> Updated
> > > the
> > > > > > wiki.
> > > > > > > > > > >
> > > > > > > > > > > 5102.4. Could we define RemoteLogSegmentMetadataUpdate
> > > > > > > > > > > and DeletePartitionUpdate?
> > > > > > > > > > >
> > > > > > > > > > > Sure, they will be added.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > 5102.5 LogSegmentData: It seems that it's easier to
> pass
> > > > > > > > > > > in leaderEpochIndex as a ByteBuffer or byte array than
> a
> > > file
> > > > > > since
> > > > > > > > it
> > > > > > > > > > will
> > > > > > > > > > > be generated in memory.
> > > > > > > > > > >
> > > > > > > > > > > Right, this is in plan.
> > > > > > > > > > >
> > > > > > > > > > > 5102.6 RemoteLogSegmentMetadata: It seems that it needs
> > > both
> > > > > > > > baseOffset
> > > > > > > > > > and
> > > > > > > > > > > startOffset. For example, deleteRecords() could move
> the
> > > > > > startOffset
> > > > > > > > to
> > > > > > > > > > the
> > > > > > > > > > > middle of a segment. If we copy the full segment to
> remote
> > > > > > storage,
> > > > > > > > the
> > > > > > > > > > > baseOffset and the startOffset will be different.
> > > > > > > > > > >
> > > > > > > > > > > Good point. startOffset is baseOffset by default, if
> not
> > > set
> > > > > > > > explicitly.
> > > > > > > > > > >
> > > > > > > > > > > 5102.7 Could we define all the public methods for
> > > > > > > > > > RemoteLogSegmentMetadata
> > > > > > > > > > > and LogSegmentData?
> > > > > > > > > > >
> > > > > > > > > > > Sure, updated the wiki.
> > > > > > > > > > >
> > > > > > > > > > > 5102.8 Could we document whether endOffset in
> > > > > > > > RemoteLogSegmentMetadata is
> > > > > > > > > > > inclusive/exclusive?
> > > > > > > > > > >
> > > > > > > > > > > It is inclusive, will update.
> > > > > > > > > > >
> > > > > > > > > > > 5103. configs:
> > > > > > > > > > > 5103.1 Could we define the default value of
> non-required
> > > > > configs
> > > > > > > > (e.g the
> > > > > > > > > > > size of new thread pools)?
> > > > > > > > > > >
> > > > > > > > > > > Sure, that makes sense.
> > > > > > > > > > >
> > > > > > > > > > > 5103.2 It seems that local.log.retention.ms should
> > > default to
> > > > > > > > > > retention.ms,
> > > > > > > > > > > instead of remote.log.retention.minutes. Similarly, it
> > > seems
> > > > > > > > > > > that local.log.retention.bytes should default to
> > > segment.bytes.
> > > > > > > > > > >
> > > > > > > > > > > Right, we do not have  remote.log.retention as we
> discussed
> > > > > > earlier.
> > > > > > > > > > > Thanks for catching the typo.
> > > > > > > > > > >
> > > > > > > > > > > 5103.3 remote.log.manager.thread.pool.size: The
> description
> > > > > says
> > > > > > > > "used in
> > > > > > > > > > > scheduling tasks to copy segments, fetch remote log
> > > indexes and
> > > > > > > > clean up
> > > > > > > > > > > remote log segments". However, there is a separate
> > > > > > > > > > > config remote.log.reader.threads for fetching remote
> data.
> > > It's
> > > > > > > > weird to
> > > > > > > > > > > fetch remote index and log in different thread pools
> since
> > > both
> > > > > > are
> > > > > > > > used
> > > > > > > > > > > for serving fetch requests.
> > > > > > > > > > >
> > > > > > > > > > > Right, remote.log.manager.thread.pool is mainly used
> for
> > > > > > copy/cleanup
> > > > > > > > > > > activities. Fetch path always goes through
> > > > > > remote.log.reader.threads.
> > > > > > > > > > >
> > > > > > > > > > > 5103.4 remote.log.manager.task.interval.ms: Is that
> the
> > > amount
> > > > > > of
> > > > > > > > time
> > > > > > > > > > to
> > > > > > > > > > > back off when there is no work to do? If so, perhaps it
> > > can be
> > > > > > > > renamed as
> > > > > > > > > > > backoff.ms.
> > > > > > > > > > >
> > > > > > > > > > > This is the delay interval for each iteration. It may
> be
> > > > > renamed
> > > > > > to
> > > > > > > > > > > remote.log.manager.task.delay.ms
> > > > > > > > > > >
> > > > > > > > > > > 5103.5 Are rlm_process_interval_ms and
> > > rlm_retry_interval_ms
> > > > > > > > configs? If
> > > > > > > > > > > so, they need to be listed in this section.
> > > > > > > > > > >
> > > > > > > > > > > remote.log.manager.task.interval.ms is the process
> > > internal,
> > > > > > retry
> > > > > > > > > > > interval is missing in the configs, which will be
> updated
> > > in
> > > > > the
> > > > > > KIP.
> > > > > > > > > > >
> > > > > > > > > > > 5104. "RLM maintains a bounded cache(possibly LRU) of
> the
> > > index
> > > > > > > > files of
> > > > > > > > > > > remote log segments to avoid multiple index fetches
> from
> > > the
> > > > > > remote
> > > > > > > > > > > storage." Is the RLM in memory or on disk? If on disk,
> > > where is
> > > > > > it
> > > > > > > > > > stored?
> > > > > > > > > > > Do we need a configuration to bound the size?
> > > > > > > > > > >
> > > > > > > > > > > It is stored on disk. They are stored in a directory
> > > > > > > > > > > `remote-log-index-cache` under log dir. We plan to
> have a
> > > > > config
> > > > > > for
> > > > > > > > > > > that instead of default. We will have a configuration
> for
> > > that.
> > > > > > > > > > >
> > > > > > > > > > > 5105. The KIP uses local-log-start-offset and Earliest
> > > Local
> > > > > > Offset
> > > > > > > > in
> > > > > > > > > > > different places. It would be useful to standardize the
> > > > > > terminology.
> > > > > > > > > > >
> > > > > > > > > > > Sure.
> > > > > > > > > > >
> > > > > > > > > > > 5106. The section on "In BuildingRemoteLogAux state".
> It
> > > listed
> > > > > > two
> > > > > > > > > > options
> > > > > > > > > > > without saying which option is chosen.
> > > > > > > > > > > We already mentioned in the KIP that we chose option-2.
> > > > > > > > > > >
> > > > > > > > > > > 5107. Follower to leader transition: It has step 2,
> but not
> > > > > step
> > > > > > 1.
> > > > > > > > > > > Step-1 is there but it is not explicitly highlighted.
> It is
> > > > > > previous
> > > > > > > > > > > table to step-2.
> > > > > > > > > > >
> > > > > > > > > > > 5108. If a consumer fetches from the remote data and
> the
> > > remote
> > > > > > > > storage
> > > > > > > > > > is
> > > > > > > > > > > not available, what error code is used in the fetch
> > > response?
> > > > > > > > > > >
> > > > > > > > > > > Good point. We have not yet defined the error for this
> > > case. We
> > > > > > need
> > > > > > > > > > > to define an error message and send the same in fetch
> > > response.
> > > > > > > > > > >
> > > > > > > > > > > 5109. "ListOffsets: For timestamps >= 0, it returns the
> > > first
> > > > > > message
> > > > > > > > > > > offset whose timestamp is >= to the given timestamp in
> the
> > > > > > request.
> > > > > > > > That
> > > > > > > > > > > means it checks in remote log time indexes first, after
> > > which
> > > > > > local
> > > > > > > > log
> > > > > > > > > > > time indexes are checked." Could you document which
> method
> > > in
> > > > > > RLMM is
> > > > > > > > > > used
> > > > > > > > > > > for this?
> > > > > > > > > > >
> > > > > > > > > > > Okay.
> > > > > > > > > > >
> > > > > > > > > > > 5110. Stopreplica: "it sets all the remote log segment
> > > metadata
> > > > > > of
> > > > > > > > that
> > > > > > > > > > > partition with a delete marker and publishes them to
> RLMM."
> > > > > This
> > > > > > > > seems
> > > > > > > > > > > outdated given the new topic deletion logic.
> > > > > > > > > > >
> > > > > > > > > > > Will update with KIP-516 related points.
> > > > > > > > > > >
> > > > > > > > > > > 5111. "RLM follower fetches the earliest offset for the
> > > > > earliest
> > > > > > > > leader
> > > > > > > > > > > epoch by calling RLMM.earliestLogOffset(TopicPartition
> > > > > > > > topicPartition,
> > > > > > > > > > int
> > > > > > > > > > > leaderEpoch) and updates that as the log start
> offset." Do
> > > we
> > > > > > need
> > > > > > > > that
> > > > > > > > > > > since replication propagates logStartOffset already?
> > > > > > > > > > >
> > > > > > > > > > > Good point. Right, existing replication protocol takes
> > > care of
> > > > > > > > > > > updating the followers’s log start offset received
> from the
> > > > > > leader.
> > > > > > > > > > >
> > > > > > > > > > > 5112. Is the default maxWaitMs of 500ms enough for
> fetching
> > > > > from
> > > > > > > > remote
> > > > > > > > > > > storage?
> > > > > > > > > > >
> > > > > > > > > > > Remote reads may fail within the current default wait
> > > time, but
> > > > > > > > > > > subsequent fetches would be able to serve as that data
> is
> > > > > stored
> > > > > > in
> > > > > > > > > > > the local cache. This cache is currently implemented in
> > > RSMs.
> > > > > > But we
> > > > > > > > > > > plan to pull this into the remote log messaging layer
> in
> > > > > future.
> > > > > > > > > > >
> > > > > > > > > > > 5113. "Committed offsets can be stored in a local file
> to
> > > avoid
> > > > > > > > reading
> > > > > > > > > > the
> > > > > > > > > > > messages again when a broker is restarted." Could you
> > > describe
> > > > > > the
> > > > > > > > format
> > > > > > > > > > > and the location of the file? Also, could the same
> message
> > > be
> > > > > > > > processed
> > > > > > > > > > by
> > > > > > > > > > > RLMM again after broker restart? If so, how do we
> handle
> > > that?
> > > > > > > > > > >
> > > > > > > > > > > Sure, we will update in the KIP.
> > > > > > > > > > >
> > > > > > > > > > > 5114. Message format
> > > > > > > > > > > 5114.1 There are two records named
> > > > > RemoteLogSegmentMetadataRecord
> > > > > > > > with
> > > > > > > > > > > apiKey 0 and 1.
> > > > > > > > > > >
> > > > > > > > > > > Nice catch, that was a typo. Fixed in the wiki.
> > > > > > > > > > >
> > > > > > > > > > > 5114.2 RemoteLogSegmentMetadataRecord: Could we
> document
> > > > > whether
> > > > > > > > > > endOffset
> > > > > > > > > > > is inclusive/exclusive?
> > > > > > > > > > > It is inclusive, will update.
> > > > > > > > > > >
> > > > > > > > > > > 5114.3 RemoteLogSegmentMetadataRecord: Could you
> explain
> > > > > > LeaderEpoch
> > > > > > > > a
> > > > > > > > > > bit
> > > > > > > > > > > more? Is that the epoch of the leader when it copies
> the
> > > > > segment
> > > > > > to
> > > > > > > > > > remote
> > > > > > > > > > > storage? Also, how will this field be used?
> > > > > > > > > > >
> > > > > > > > > > > Right, this is the leader epoch of the broker which
> copied
> > > this
> > > > > > > > > > > segment. This is helpful in reason about which broker
> > > copied
> > > > > the
> > > > > > > > > > > segment to remote storage.
> > > > > > > > > > >
> > > > > > > > > > > 5114.4 EventTimestamp: Could you explain this a bit
> more?
> > > Each
> > > > > > > > record in
> > > > > > > > > > > Kafka already has a timestamp field. Could we just use
> > > that?
> > > > > > > > > > >
> > > > > > > > > > > This is the  timestamp at which  the respective event
> > > occurred.
> > > > > > Added
> > > > > > > > > > > this  to RemoteLogSegmentMetadata as RLMM can be  any
> other
> > > > > > > > > > > implementation. We thought about that but it looked
> > > cleaner to
> > > > > > use at
> > > > > > > > > > > the message structure level instead of getting that
> from
> > > the
> > > > > > consumer
> > > > > > > > > > > record and using that to build the respective event.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > 5114.5 SegmentSizeInBytes: Could this just be int32?
> > > > > > > > > > >
> > > > > > > > > > > Right, it looks like config allows only int value >=
> 14.
> > > > > > > > > > >
> > > > > > > > > > > 5115. RemoteLogCleaner(RLC): This could be confused
> with
> > > the
> > > > > log
> > > > > > > > cleaner
> > > > > > > > > > > for compaction. Perhaps it can be renamed to sth like
> > > > > > > > > > > RemotePartitionRemover.
> > > > > > > > > > >
> > > > > > > > > > > I am fine with RemotePartitionRemover or
> > > > > > RemoteLogDeletionManager(we
> > > > > > > > > > > have other manager classes like RLM, RLMM).
> > > > > > > > > > >
> > > > > > > > > > > 5116. "RLC receives the delete_partition_marked and
> > > processes
> > > > > it
> > > > > > if
> > > > > > > > it is
> > > > > > > > > > > not yet processed earlier." How does it know whether
> > > > > > > > > > > delete_partition_marked has been processed earlier?
> > > > > > > > > > >
> > > > > > > > > > > This is to handle duplicate delete_partition_marked
> > > events. RLC
> > > > > > > > > > > internally maintains a state for the delete_partition
> > > events
> > > > > and
> > > > > > if
> > > > > > > > it
> > > > > > > > > > > already has an existing event then it ignores if it is
> > > already
> > > > > > being
> > > > > > > > > > > processed.
> > > > > > > > > > >
> > > > > > > > > > > 5117. Should we add a new MessageFormatter to read the
> tier
> > > > > > metadata
> > > > > > > > > > topic?
> > > > > > > > > > >
> > > > > > > > > > > Right, this is in plan but did not mention it in the
> KIP.
> > > This
> > > > > > will
> > > > > > > > be
> > > > > > > > > > > useful for debugging purposes too.
> > > > > > > > > > >
> > > > > > > > > > > 5118. "Maximum remote log reader thread pool task queue
> > > size.
> > > > > If
> > > > > > the
> > > > > > > > task
> > > > > > > > > > > queue is full, broker will stop reading remote log
> > > segments."
> > > > > > What
> > > > > > > > do we
> > > > > > > > > > > return to the fetch request in this case?
> > > > > > > > > > >
> > > > > > > > > > > We return an error response for that partition.
> > > > > > > > > > >
> > > > > > > > > > > 5119. It would be useful to list all things not
> supported
> > > in
> > > > > the
> > > > > > > > first
> > > > > > > > > > > version in a Future work or Limitations section. For
> > > example,
> > > > > > > > compacted
> > > > > > > > > > > topic, JBOD, changing remote.log.storage.enable from
> true
> > > to
> > > > > > false,
> > > > > > > > etc.
> > > > > > > > > > >
> > > > > > > > > > > We already have a non-goals section which is filled
> with
> > > some
> > > > > of
> > > > > > > > these
> > > > > > > > > > > details. Do we need another limitations section?
> > > > > > > > > > >
> > > > > > > > > > > Thanks,
> > > > > > > > > > > Satish.
> > > > > > > > > > >
> > > > > > > > > > > On Wed, Nov 4, 2020 at 11:27 PM Jun Rao <
> jun@confluent.io>
> > > > > > wrote:
> > > > > > > > > > > >
> > > > > > > > > > > > Hi, Satish,
> > > > > > > > > > > >
> > > > > > > > > > > > Thanks for the updated KIP. A few more comments
> below.
> > > > > > > > > > > >
> > > > > > > > > > > > 605.2 "Build the local leader epoch cache by cutting
> the
> > > > > leader
> > > > > > > > epoch
> > > > > > > > > > > > sequence received from remote storage to [LSO,
> ELO]." I
> > > > > > mentioned
> > > > > > > > an
> > > > > > > > > > issue
> > > > > > > > > > > > earlier. Suppose the leader's local start offset is
> 100.
> > > The
> > > > > > > > follower
> > > > > > > > > > finds
> > > > > > > > > > > > a remote segment covering offset range [80, 120). The
> > > > > > producerState
> > > > > > > > > > with
> > > > > > > > > > > > this remote segment is up to offset 120. To trim the
> > > > > > producerState
> > > > > > > > to
> > > > > > > > > > > > offset 100 requires more work since one needs to
> > > download the
> > > > > > > > previous
> > > > > > > > > > > > producerState up to offset 80 and then replay the
> > > messages
> > > > > > from 80
> > > > > > > > to
> > > > > > > > > > 100.
> > > > > > > > > > > > It seems that it's simpler in this case for the
> follower
> > > just
> > > > > > to
> > > > > > > > take
> > > > > > > > > > the
> > > > > > > > > > > > remote segment as it is and start fetching from
> offset
> > > 120.
> > > > > > > > > > > >
> > > > > > > > > > > > 5016. Just to echo what Kowshik was saying. It seems
> that
> > > > > > > > > > > > RLMM.onPartitionLeadershipChanges() is only called
> on the
> > > > > > replicas
> > > > > > > > for
> > > > > > > > > > a
> > > > > > > > > > > > partition, not on the replicas for the
> > > > > > > > __remote_log_segment_metadata
> > > > > > > > > > > > partition. It's not clear how the leader of
> > > > > > > > > > __remote_log_segment_metadata
> > > > > > > > > > > > obtains the metadata for remote segments for
> deletion.
> > > > > > > > > > > >
> > > > > > > > > > > > 5100. KIP-516 has been accepted and is being
> implemented
> > > now.
> > > > > > > > Could you
> > > > > > > > > > > > update the KIP based on topicID?
> > > > > > > > > > > >
> > > > > > > > > > > > 5101. RLMM: It would be useful to clarify how the
> > > following
> > > > > two
> > > > > > > > APIs
> > > > > > > > > > are
> > > > > > > > > > > > used. According to the wiki, the former is used for
> topic
> > > > > > deletion
> > > > > > > > and
> > > > > > > > > > the
> > > > > > > > > > > > latter is used for retention. It seems that retention
> > > should
> > > > > > use
> > > > > > > > the
> > > > > > > > > > former
> > > > > > > > > > > > since remote segments without a matching epoch in the
> > > leader
> > > > > > > > > > (potentially
> > > > > > > > > > > > due to unclean leader election) also need to be
> garbage
> > > > > > collected.
> > > > > > > > The
> > > > > > > > > > > > latter seems to be used for the new leader to
> determine
> > > the
> > > > > > last
> > > > > > > > tiered
> > > > > > > > > > > > segment.
> > > > > > > > > > > >     default Iterator<RemoteLogSegmentMetadata>
> > > > > > > > > > > > listRemoteLogSegments(TopicPartition topicPartition)
> > > > > > > > > > > >     Iterator<RemoteLogSegmentMetadata>
> > > > > > > > > > listRemoteLogSegments(TopicPartition
> > > > > > > > > > > > topicPartition, long leaderEpoch);
> > > > > > > > > > > >
> > > > > > > > > > > > 5102. RSM:
> > > > > > > > > > > > 5102.1 For methods like fetchLogSegmentData(), it
> seems
> > > that
> > > > > > they
> > > > > > > > can
> > > > > > > > > > > > use RemoteLogSegmentId instead of
> > > RemoteLogSegmentMetadata.
> > > > > > > > > > > > 5102.2 In fetchLogSegmentData(), should we use long
> > > instead
> > > > > of
> > > > > > > > Long?
> > > > > > > > > > > > 5102.3 Why only some of the methods have default
> > > > > > implementation and
> > > > > > > > > > others
> > > > > > > > > > > > don't?
> > > > > > > > > > > > 5102.4. Could we define
> RemoteLogSegmentMetadataUpdate
> > > > > > > > > > > > and DeletePartitionUpdate?
> > > > > > > > > > > > 5102.5 LogSegmentData: It seems that it's easier to
> pass
> > > > > > > > > > > > in leaderEpochIndex as a ByteBuffer or byte array
> than a
> > > file
> > > > > > > > since it
> > > > > > > > > > will
> > > > > > > > > > > > be generated in memory.
> > > > > > > > > > > > 5102.6 RemoteLogSegmentMetadata: It seems that it
> needs
> > > both
> > > > > > > > > > baseOffset and
> > > > > > > > > > > > startOffset. For example, deleteRecords() could move
> the
> > > > > > > > startOffset
> > > > > > > > > > to the
> > > > > > > > > > > > middle of a segment. If we copy the full segment to
> > > remote
> > > > > > > > storage, the
> > > > > > > > > > > > baseOffset and the startOffset will be different.
> > > > > > > > > > > > 5102.7 Could we define all the public methods for
> > > > > > > > > > RemoteLogSegmentMetadata
> > > > > > > > > > > > and LogSegmentData?
> > > > > > > > > > > > 5102.8 Could we document whether endOffset in
> > > > > > > > RemoteLogSegmentMetadata
> > > > > > > > > > is
> > > > > > > > > > > > inclusive/exclusive?
> > > > > > > > > > > >
> > > > > > > > > > > > 5103. configs:
> > > > > > > > > > > > 5103.1 Could we define the default value of
> non-required
> > > > > > configs
> > > > > > > > (e.g
> > > > > > > > > > the
> > > > > > > > > > > > size of new thread pools)?
> > > > > > > > > > > > 5103.2 It seems that local.log.retention.ms should
> > > default
> > > > > to
> > > > > > > > > > retention.ms,
> > > > > > > > > > > > instead of remote.log.retention.minutes. Similarly,
> it
> > > seems
> > > > > > > > > > > > that local.log.retention.bytes should default to
> > > > > segment.bytes.
> > > > > > > > > > > > 5103.3 remote.log.manager.thread.pool.size: The
> > > description
> > > > > > says
> > > > > > > > "used
> > > > > > > > > > in
> > > > > > > > > > > > scheduling tasks to copy segments, fetch remote log
> > > indexes
> > > > > and
> > > > > > > > clean
> > > > > > > > > > up
> > > > > > > > > > > > remote log segments". However, there is a separate
> > > > > > > > > > > > config remote.log.reader.threads for fetching remote
> > > data.
> > > > > It's
> > > > > > > > weird
> > > > > > > > > > to
> > > > > > > > > > > > fetch remote index and log in different thread pools
> > > since
> > > > > > both are
> > > > > > > > > > used
> > > > > > > > > > > > for serving fetch requests.
> > > > > > > > > > > > 5103.4 remote.log.manager.task.interval.ms: Is that
> the
> > > > > > amount of
> > > > > > > > > > time to
> > > > > > > > > > > > back off when there is no work to do? If so, perhaps
> it
> > > can
> > > > > be
> > > > > > > > renamed
> > > > > > > > > > as
> > > > > > > > > > > > backoff.ms.
> > > > > > > > > > > > 5103.5 Are rlm_process_interval_ms and
> > > rlm_retry_interval_ms
> > > > > > > > configs?
> > > > > > > > > > If
> > > > > > > > > > > > so, they need to be listed in this section.
> > > > > > > > > > > >
> > > > > > > > > > > > 5104. "RLM maintains a bounded cache(possibly LRU)
> of the
> > > > > index
> > > > > > > > files
> > > > > > > > > > of
> > > > > > > > > > > > remote log segments to avoid multiple index fetches
> from
> > > the
> > > > > > remote
> > > > > > > > > > > > storage." Is the RLM in memory or on disk? If on
> disk,
> > > where
> > > > > > is it
> > > > > > > > > > stored?
> > > > > > > > > > > > Do we need a configuration to bound the size?
> > > > > > > > > > > >
> > > > > > > > > > > > 5105. The KIP uses local-log-start-offset and
> Earliest
> > > Local
> > > > > > > > Offset in
> > > > > > > > > > > > different places. It would be useful to standardize
> the
> > > > > > > > terminology.
> > > > > > > > > > > >
> > > > > > > > > > > > 5106. The section on "In BuildingRemoteLogAux
> state". It
> > > > > > listed two
> > > > > > > > > > options
> > > > > > > > > > > > without saying which option is chosen.
> > > > > > > > > > > >
> > > > > > > > > > > > 5107. Follower to leader transition: It has step 2,
> but
> > > not
> > > > > > step 1.
> > > > > > > > > > > >
> > > > > > > > > > > > 5108. If a consumer fetches from the remote data and
> the
> > > > > remote
> > > > > > > > > > storage is
> > > > > > > > > > > > not available, what error code is used in the fetch
> > > response?
> > > > > > > > > > > >
> > > > > > > > > > > > 5109. "ListOffsets: For timestamps >= 0, it returns
> the
> > > first
> > > > > > > > message
> > > > > > > > > > > > offset whose timestamp is >= to the given timestamp
> in
> > > the
> > > > > > request.
> > > > > > > > > > That
> > > > > > > > > > > > means it checks in remote log time indexes first,
> after
> > > which
> > > > > > > > local log
> > > > > > > > > > > > time indexes are checked." Could you document which
> > > method in
> > > > > > RLMM
> > > > > > > > is
> > > > > > > > > > used
> > > > > > > > > > > > for this?
> > > > > > > > > > > >
> > > > > > > > > > > > 5110. Stopreplica: "it sets all the remote log
> segment
> > > > > > metadata of
> > > > > > > > that
> > > > > > > > > > > > partition with a delete marker and publishes them to
> > > RLMM."
> > > > > > This
> > > > > > > > seems
> > > > > > > > > > > > outdated given the new topic deletion logic.
> > > > > > > > > > > >
> > > > > > > > > > > > 5111. "RLM follower fetches the earliest offset for
> the
> > > > > > earliest
> > > > > > > > leader
> > > > > > > > > > > > epoch by calling
> RLMM.earliestLogOffset(TopicPartition
> > > > > > > > topicPartition,
> > > > > > > > > > int
> > > > > > > > > > > > leaderEpoch) and updates that as the log start
> offset."
> > > Do we
> > > > > > need
> > > > > > > > that
> > > > > > > > > > > > since replication propagates logStartOffset already?
> > > > > > > > > > > >
> > > > > > > > > > > > 5112. Is the default maxWaitMs of 500ms enough for
> > > fetching
> > > > > > from
> > > > > > > > remote
> > > > > > > > > > > > storage?
> > > > > > > > > > > >
> > > > > > > > > > > > 5113. "Committed offsets can be stored in a local
> file to
> > > > > avoid
> > > > > > > > > > reading the
> > > > > > > > > > > > messages again when a broker is restarted." Could you
> > > > > describe
> > > > > > the
> > > > > > > > > > format
> > > > > > > > > > > > and the location of the file? Also, could the same
> > > message be
> > > > > > > > > > processed by
> > > > > > > > > > > > RLMM again after broker restart? If so, how do we
> handle
> > > > > that?
> > > > > > > > > > > >
> > > > > > > > > > > > 5114. Message format
> > > > > > > > > > > > 5114.1 There are two records named
> > > > > > RemoteLogSegmentMetadataRecord
> > > > > > > > with
> > > > > > > > > > > > apiKey 0 and 1.
> > > > > > > > > > > > 5114.2 RemoteLogSegmentMetadataRecord: Could we
> document
> > > > > > whether
> > > > > > > > > > endOffset
> > > > > > > > > > > > is inclusive/exclusive?
> > > > > > > > > > > > 5114.3 RemoteLogSegmentMetadataRecord: Could you
> explain
> > > > > > > > LeaderEpoch a
> > > > > > > > > > bit
> > > > > > > > > > > > more? Is that the epoch of the leader when it copies
> the
> > > > > > segment to
> > > > > > > > > > remote
> > > > > > > > > > > > storage? Also, how will this field be used?
> > > > > > > > > > > > 5114.4 EventTimestamp: Could you explain this a bit
> more?
> > > > > Each
> > > > > > > > record
> > > > > > > > > > in
> > > > > > > > > > > > Kafka already has a timestamp field. Could we just
> use
> > > that?
> > > > > > > > > > > > 5114.5 SegmentSizeInBytes: Could this just be int32?
> > > > > > > > > > > >
> > > > > > > > > > > > 5115. RemoteLogCleaner(RLC): This could be confused
> with
> > > the
> > > > > > log
> > > > > > > > > > cleaner
> > > > > > > > > > > > for compaction. Perhaps it can be renamed to sth like
> > > > > > > > > > > > RemotePartitionRemover.
> > > > > > > > > > > >
> > > > > > > > > > > > 5116. "RLC receives the delete_partition_marked and
> > > processes
> > > > > > it
> > > > > > > > if it
> > > > > > > > > > is
> > > > > > > > > > > > not yet processed earlier." How does it know whether
> > > > > > > > > > > > delete_partition_marked has been processed earlier?
> > > > > > > > > > > >
> > > > > > > > > > > > 5117. Should we add a new MessageFormatter to read
> the
> > > tier
> > > > > > > > metadata
> > > > > > > > > > topic?
> > > > > > > > > > > >
> > > > > > > > > > > > 5118. "Maximum remote log reader thread pool task
> queue
> > > size.
> > > > > > If
> > > > > > > > the
> > > > > > > > > > task
> > > > > > > > > > > > queue is full, broker will stop reading remote log
> > > segments."
> > > > > > What
> > > > > > > > do
> > > > > > > > > > we
> > > > > > > > > > > > return to the fetch request in this case?
> > > > > > > > > > > >
> > > > > > > > > > > > 5119. It would be useful to list all things not
> > > supported in
> > > > > > the
> > > > > > > > first
> > > > > > > > > > > > version in a Future work or Limitations section. For
> > > example,
> > > > > > > > compacted
> > > > > > > > > > > > topic, JBOD, changing remote.log.storage.enable from
> > > true to
> > > > > > false,
> > > > > > > > > > etc.
> > > > > > > > > > > >
> > > > > > > > > > > > Thanks,
> > > > > > > > > > > >
> > > > > > > > > > > > Jun
> > > > > > > > > > > >
> > > > > > > > > > > > On Tue, Oct 27, 2020 at 5:57 PM Kowshik Prakasam <
> > > > > > > > > > kprakasam@confluent.io>
> > > > > > > > > > > > wrote:
> > > > > > > > > > > >
> > > > > > > > > > > > > Hi Satish,
> > > > > > > > > > > > >
> > > > > > > > > > > > > Thanks for the updates to the KIP. Here are my
> first
> > > batch
> > > > > of
> > > > > > > > > > > > > comments/suggestions on the latest version of the
> KIP.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5012. In the RemoteStorageManager interface, there
> is
> > > an
> > > > > API
> > > > > > > > defined
> > > > > > > > > > for
> > > > > > > > > > > > > each file type. For example, fetchOffsetIndex,
> > > > > > > > fetchTimestampIndex
> > > > > > > > > > etc. To
> > > > > > > > > > > > > avoid the duplication, I'd suggest we can instead
> have
> > > a
> > > > > > FileType
> > > > > > > > > > enum and
> > > > > > > > > > > > > a common get API based on the FileType.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5013. There are some references to the Google doc
> in
> > > the
> > > > > > KIP. I
> > > > > > > > > > wasn't sure
> > > > > > > > > > > > > if the Google doc is expected to be in sync with
> the
> > > > > > contents of
> > > > > > > > the
> > > > > > > > > > wiki.
> > > > > > > > > > > > > Going forward, it seems easier if just the KIP is
> > > > > maintained
> > > > > > as
> > > > > > > > the
> > > > > > > > > > source
> > > > > > > > > > > > > of truth. In this regard, could you please move
> all the
> > > > > > > > references
> > > > > > > > > > to the
> > > > > > > > > > > > > Google doc, maybe to a separate References section
> at
> > > the
> > > > > > bottom
> > > > > > > > of
> > > > > > > > > > the
> > > > > > > > > > > > > KIP?
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5014. There are some TODO sections in the KIP.
> Would
> > > these
> > > > > be
> > > > > > > > filled
> > > > > > > > > > up in
> > > > > > > > > > > > > future iterations?
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5015. Under "Topic deletion lifecycle", I'm trying
> to
> > > > > > understand
> > > > > > > > why
> > > > > > > > > > do we
> > > > > > > > > > > > > need delete_partition_marked as well as the
> > > > > > > > delete_partition_started
> > > > > > > > > > > > > messages. I couldn't spot a drawback if supposing
> we
> > > > > > simplified
> > > > > > > > the
> > > > > > > > > > design
> > > > > > > > > > > > > such that the controller would only write
> > > > > > > > delete_partition_started
> > > > > > > > > > message,
> > > > > > > > > > > > > and RemoteLogCleaner (RLC) instance picks it up for
> > > > > > processing.
> > > > > > > > What
> > > > > > > > > > am I
> > > > > > > > > > > > > missing?
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5016. Under "Topic deletion lifecycle", step (4) is
> > > > > > mentioned as
> > > > > > > > > > "RLC gets
> > > > > > > > > > > > > all the remote log segments for the partition and
> each
> > > of
> > > > > > these
> > > > > > > > > > remote log
> > > > > > > > > > > > > segments is deleted with the next steps.". Since
> the
> > > RLC
> > > > > > instance
> > > > > > > > > > runs on
> > > > > > > > > > > > > each tier topic partition leader, how does the RLC
> > > then get
> > > > > > the
> > > > > > > > list
> > > > > > > > > > of
> > > > > > > > > > > > > remote log segments to be deleted? It will be
> useful
> > > to add
> > > > > > that
> > > > > > > > > > detail to
> > > > > > > > > > > > > the KIP.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5017. Under "Public Interfaces -> Configs", there
> is a
> > > line
> > > > > > > > > > mentioning "We
> > > > > > > > > > > > > will support flipping remote.log.storage.enable in
> next
> > > > > > > > versions."
> > > > > > > > > > It will
> > > > > > > > > > > > > be useful to mention this in the "Future Work"
> section
> > > of
> > > > > > the KIP
> > > > > > > > > > too.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5018. The KIP introduces a number of configuration
> > > > > > parameters. It
> > > > > > > > > > will be
> > > > > > > > > > > > > useful to mention in the KIP if the user should
> assume
> > > > > these
> > > > > > as
> > > > > > > > > > static
> > > > > > > > > > > > > configuration in the server.properties file, or
> dynamic
> > > > > > > > > > configuration which
> > > > > > > > > > > > > can be modified without restarting the broker.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5019.  Maybe this is planned as a future update to
> the
> > > KIP,
> > > > > > but I
> > > > > > > > > > thought
> > > > > > > > > > > > > I'd mention it here. Could you please add details
> to
> > > the
> > > > > KIP
> > > > > > on
> > > > > > > > why
> > > > > > > > > > RocksDB
> > > > > > > > > > > > > was chosen as the default cache implementation of
> > > RLMM, and
> > > > > > how
> > > > > > > > it
> > > > > > > > > > is going
> > > > > > > > > > > > > to be used? Were alternatives compared/considered?
> For
> > > > > > example,
> > > > > > > > it
> > > > > > > > > > would be
> > > > > > > > > > > > > useful to explain/evaluate the following: 1)
> > > debuggability
> > > > > > of the
> > > > > > > > > > RocksDB
> > > > > > > > > > > > > JNI interface, 2) performance, 3) portability
> across
> > > > > > platforms
> > > > > > > > and 4)
> > > > > > > > > > > > > interface parity of RocksDB’s JNI api with it's
> > > underlying
> > > > > > C/C++
> > > > > > > > api.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5020. Following up on (5019), for the RocksDB
> cache, it
> > > > > will
> > > > > > be
> > > > > > > > > > useful to
> > > > > > > > > > > > > explain the relationship/mapping between the
> following
> > > in
> > > > > the
> > > > > > > > KIP:
> > > > > > > > > > 1) # of
> > > > > > > > > > > > > tiered partitions, 2) # of partitions of metadata
> topic
> > > > > > > > > > > > > __remote_log_metadata and 3) # of RocksDB
> instances.
> > > i.e.
> > > > > is
> > > > > > the
> > > > > > > > > > plan to
> > > > > > > > > > > > > have a RocksDB instance per tiered partition, or
> per
> > > > > metadata
> > > > > > > > topic
> > > > > > > > > > > > > partition, or just 1 for per broker?
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5021. I was looking at the implementation
> prototype (PR
> > > > > link:
> > > > > > > > > > > > > https://github.com/apache/kafka/pull/7561). It
> seems
> > > that
> > > > > a
> > > > > > > > boolean
> > > > > > > > > > > > > attribute is being introduced into the Log layer to
> > > check
> > > > > if
> > > > > > > > remote
> > > > > > > > > > log
> > > > > > > > > > > > > capability is enabled. While the boolean footprint
> is
> > > small
> > > > > > at
> > > > > > > > the
> > > > > > > > > > moment,
> > > > > > > > > > > > > this can easily grow in the future and become
> harder to
> > > > > > > > > > > > > test/maintain, considering that the Log layer is
> > > already
> > > > > > pretty
> > > > > > > > > > complex. We
> > > > > > > > > > > > > should start thinking about how to manage such
> changes
> > > to
> > > > > > the Log
> > > > > > > > > > layer
> > > > > > > > > > > > > (for the purpose of improved testability, better
> > > separation
> > > > > > of
> > > > > > > > > > concerns and
> > > > > > > > > > > > > readability). One proposal I have is to take a step
> > > back
> > > > > and
> > > > > > > > define a
> > > > > > > > > > > > > higher level Log interface. Then, the Broker code
> can
> > > be
> > > > > > changed
> > > > > > > > to
> > > > > > > > > > use
> > > > > > > > > > > > > this interface. It can be changed such that only a
> > > handle
> > > > > to
> > > > > > the
> > > > > > > > > > interface
> > > > > > > > > > > > > is exposed to other components (such as LogCleaner,
> > > > > > > > ReplicaManager
> > > > > > > > > > etc.)
> > > > > > > > > > > > > and not the underlying Log object. This approach
> keeps
> > > the
> > > > > > user
> > > > > > > > of
> > > > > > > > > > the Log
> > > > > > > > > > > > > layer agnostic of the whereabouts of the data.
> > > Underneath
> > > > > the
> > > > > > > > > > interface,
> > > > > > > > > > > > > the implementing classes can completely separate
> local
> > > log
> > > > > > > > > > capabilities
> > > > > > > > > > > > > from the remote log. For example, the Log class
> can be
> > > > > > > > simplified to
> > > > > > > > > > only
> > > > > > > > > > > > > manage logic surrounding local log segments and
> > > metadata.
> > > > > > > > > > Additionally, a
> > > > > > > > > > > > > wrapper class can be provided (implementing the
> higher
> > > > > level
> > > > > > Log
> > > > > > > > > > interface)
> > > > > > > > > > > > > which will contain any/all logic surrounding tiered
> > > data.
> > > > > The
> > > > > > > > wrapper
> > > > > > > > > > > > > class will wrap around an instance of the Log class
> > > > > > delegating
> > > > > > > > the
> > > > > > > > > > local
> > > > > > > > > > > > > log logic to it. Finally, a handle to the wrapper
> > > class can
> > > > > > be
> > > > > > > > > > exposed to
> > > > > > > > > > > > > the other components wherever they need a handle
> to the
> > > > > > higher
> > > > > > > > level
> > > > > > > > > > Log
> > > > > > > > > > > > > interface.
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > Cheers,
> > > > > > > > > > > > > Kowshik
> > > > > > > > > > > > >
> > > > > > > > > > > > > On Mon, Oct 26, 2020 at 9:52 PM Satish Duggana <
> > > > > > > > > > satish.duggana@gmail.com>
> > > > > > > > > > > > > wrote:
> > > > > > > > > > > > >
> > > > > > > > > > > > > > Hi,
> > > > > > > > > > > > > > KIP is updated with 1) topic deletion lifecycle
> and
> > > its
> > > > > > related
> > > > > > > > > > items
> > > > > > > > > > > > > > 2) Protocol changes(mainly related to
> ListOffsets)
> > > and
> > > > > > other
> > > > > > > > minor
> > > > > > > > > > > > > > changes.
> > > > > > > > > > > > > > Please go through them and let us know your
> comments.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > Satish.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > On Mon, Sep 28, 2020 at 9:10 PM Satish Duggana <
> > > > > > > > > > satish.duggana@gmail.com
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Hi Dhruvil,
> > > > > > > > > > > > > > > Thanks for looking into the KIP and sending
> your
> > > > > > comments.
> > > > > > > > Sorry
> > > > > > > > > > for
> > > > > > > > > > > > > > > the late reply, missed it in the mail thread.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 1. Could you describe how retention would work
> with
> > > > > this
> > > > > > KIP
> > > > > > > > and
> > > > > > > > > > which
> > > > > > > > > > > > > > > threads are responsible for driving this work?
> I
> > > > > believe
> > > > > > > > there
> > > > > > > > > > are 3
> > > > > > > > > > > > > > kinds
> > > > > > > > > > > > > > > of retention processes we are looking at:
> > > > > > > > > > > > > > >   (a) Regular retention for data in tiered
> storage
> > > as
> > > > > per
> > > > > > > > > > configured `
> > > > > > > > > > > > > > > retention.ms` / `retention.bytes`.
> > > > > > > > > > > > > > >   (b) Local retention for data in local
> storage as
> > > per
> > > > > > > > > > configured `
> > > > > > > > > > > > > > > local.log.retention.ms` /
> > > `local.log.retention.bytes`
> > > > > > > > > > > > > > >   (c) Possibly regular retention for data in
> local
> > > > > > storage,
> > > > > > > > if
> > > > > > > > > > the
> > > > > > > > > > > > > > tiering
> > > > > > > > > > > > > > > task is lagging or for data that is below the
> log
> > > start
> > > > > > > > offset.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Local log retention is done by the existing log
> > > cleanup
> > > > > > > > tasks.
> > > > > > > > > > These
> > > > > > > > > > > > > > > are not done for segments that are not yet
> copied
> > > to
> > > > > > remote
> > > > > > > > > > storage.
> > > > > > > > > > > > > > > Remote log cleanup is done by the leader
> > > partition’s
> > > > > > RLMTask.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 2. When does a segment become eligible to be
> > > tiered? Is
> > > > > > it as
> > > > > > > > > > soon as
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > segment is rolled and the end offset is less
> than
> > > the
> > > > > > last
> > > > > > > > stable
> > > > > > > > > > > > > offset
> > > > > > > > > > > > > > as
> > > > > > > > > > > > > > > mentioned in the KIP? I wonder if we need to
> > > consider
> > > > > > other
> > > > > > > > > > parameters
> > > > > > > > > > > > > > too,
> > > > > > > > > > > > > > > like the highwatermark so that we are
> guaranteed
> > > that
> > > > > > what
> > > > > > > > we are
> > > > > > > > > > > > > tiering
> > > > > > > > > > > > > > > has been committed to the log and accepted by
> the
> > > ISR.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > AFAIK, last stable offset is always <=
> > > highwatermark.
> > > > > > This
> > > > > > > > will
> > > > > > > > > > make
> > > > > > > > > > > > > > > sure we are always tiering the message segments
> > > which
> > > > > > have
> > > > > > > > been
> > > > > > > > > > > > > > > accepted by ISR and transactionally completed.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 3. The section on "Follower Fetch Scenarios" is
> > > useful
> > > > > > but
> > > > > > > > is a
> > > > > > > > > > bit
> > > > > > > > > > > > > > > difficult to parse at the moment. It would be
> > > useful to
> > > > > > > > > > summarize the
> > > > > > > > > > > > > > > changes we need in the ReplicaFetcher.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > It may become difficult for users to
> read/follow
> > > if we
> > > > > > add
> > > > > > > > code
> > > > > > > > > > changes
> > > > > > > > > > > > > > here.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 4. Related to the above, it's a bit unclear
> how we
> > > are
> > > > > > > > planning
> > > > > > > > > > on
> > > > > > > > > > > > > > > restoring the producer state for a new replica.
> > > Could
> > > > > you
> > > > > > > > expand
> > > > > > > > > > on
> > > > > > > > > > > > > that?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > It is mentioned in the KIP
> > > BuildingRemoteLogAuxState is
> > > > > > > > > > introduced to
> > > > > > > > > > > > > > > build the state like leader epoch sequence and
> > > producer
> > > > > > > > snapshots
> > > > > > > > > > > > > > > before it starts fetching the data from the
> > > leader. We
> > > > > > will
> > > > > > > > make
> > > > > > > > > > it
> > > > > > > > > > > > > > > clear in the KIP.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5. Similarly, it would be worth summarizing the
> > > > > behavior
> > > > > > on
> > > > > > > > > > unclean
> > > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > election. There are several scenarios to
> consider
> > > here:
> > > > > > data
> > > > > > > > > > loss from
> > > > > > > > > > > > > > > local log, data loss from remote log, data loss
> > > from
> > > > > > metadata
> > > > > > > > > > topic,
> > > > > > > > > > > > > etc.
> > > > > > > > > > > > > > > It's worth describing these in detail.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > We mentioned the cases about unclean leader
> > > election in
> > > > > > the
> > > > > > > > > > follower
> > > > > > > > > > > > > > > fetch scenarios.
> > > > > > > > > > > > > > > If there are errors while fetching data from
> remote
> > > > > > store or
> > > > > > > > > > metadata
> > > > > > > > > > > > > > > store, it will work the same way as it works
> with
> > > local
> > > > > > log.
> > > > > > > > It
> > > > > > > > > > > > > > > returns the error back to the caller. Please
> let us
> > > > > know
> > > > > > if
> > > > > > > > I am
> > > > > > > > > > > > > > > missing your point here.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 7. For a READ_COMMITTED FetchRequest, how do we
> > > > > retrieve
> > > > > > and
> > > > > > > > > > return the
> > > > > > > > > > > > > > > aborted transaction metadata?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > When a fetch for a remote log is accessed, we
> will
> > > > > fetch
> > > > > > > > aborted
> > > > > > > > > > > > > > > transactions along with the segment if it is
> not
> > > found
> > > > > > in the
> > > > > > > > > > local
> > > > > > > > > > > > > > > index cache. This includes the case of
> transaction
> > > > > index
> > > > > > not
> > > > > > > > > > existing
> > > > > > > > > > > > > > > in the remote log segment. That means, the
> cache
> > > entry
> > > > > > can be
> > > > > > > > > > empty or
> > > > > > > > > > > > > > > have a list of aborted transactions.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 8. The `LogSegmentData` class assumes that we
> have
> > > a
> > > > > log
> > > > > > > > segment,
> > > > > > > > > > > > > offset
> > > > > > > > > > > > > > > index, time index, transaction index, producer
> > > snapshot
> > > > > > and
> > > > > > > > > > leader
> > > > > > > > > > > > > epoch
> > > > > > > > > > > > > > > index. How do we deal with cases where we do
> not
> > > have
> > > > > > one or
> > > > > > > > > > more of
> > > > > > > > > > > > > > these?
> > > > > > > > > > > > > > > For example, we may not have a transaction
> index or
> > > > > > producer
> > > > > > > > > > snapshot
> > > > > > > > > > > > > > for a
> > > > > > > > > > > > > > > particular segment. The former is optional,
> and the
> > > > > > latter is
> > > > > > > > > > only kept
> > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > up to the 3 latest segments.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > This is a good point,  we discussed this in the
> > > last
> > > > > > meeting.
> > > > > > > > > > > > > > > Transaction index is optional and we will copy
> them
> > > > > only
> > > > > > if
> > > > > > > > it
> > > > > > > > > > exists.
> > > > > > > > > > > > > > > We want to keep all the producer snapshots at
> each
> > > log
> > > > > > > > segment
> > > > > > > > > > rolling
> > > > > > > > > > > > > > > and they can be removed if the log copying is
> > > > > successful
> > > > > > and
> > > > > > > > it
> > > > > > > > > > still
> > > > > > > > > > > > > > > maintains the existing latest 3 segments, We
> only
> > > > > delete
> > > > > > the
> > > > > > > > > > producer
> > > > > > > > > > > > > > > snapshots which have been copied to remote log
> > > segments
> > > > > > on
> > > > > > > > > > leader.
> > > > > > > > > > > > > > > Follower will keep the log segments beyond the
> > > segments
> > > > > > which
> > > > > > > > > > have not
> > > > > > > > > > > > > > > been copied to remote storage. We will update
> the
> > > KIP
> > > > > > with
> > > > > > > > these
> > > > > > > > > > > > > > > details.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > Satish.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > On Thu, Sep 17, 2020 at 1:47 AM Dhruvil Shah <
> > > > > > > > > > dhruvil@confluent.io>
> > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Hi Satish, Harsha,
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Thanks for the KIP. Few questions below:
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 1. Could you describe how retention would
> work
> > > with
> > > > > > this
> > > > > > > > KIP
> > > > > > > > > > and
> > > > > > > > > > > > > which
> > > > > > > > > > > > > > > > threads are responsible for driving this
> work? I
> > > > > > believe
> > > > > > > > there
> > > > > > > > > > are 3
> > > > > > > > > > > > > > kinds
> > > > > > > > > > > > > > > > of retention processes we are looking at:
> > > > > > > > > > > > > > > >   (a) Regular retention for data in tiered
> > > storage as
> > > > > > per
> > > > > > > > > > configured
> > > > > > > > > > > > > `
> > > > > > > > > > > > > > > > retention.ms` / `retention.bytes`.
> > > > > > > > > > > > > > > >   (b) Local retention for data in local
> storage
> > > as
> > > > > per
> > > > > > > > > > configured `
> > > > > > > > > > > > > > > > local.log.retention.ms` /
> > > > > `local.log.retention.bytes`
> > > > > > > > > > > > > > > >   (c) Possibly regular retention for data in
> > > local
> > > > > > > > storage, if
> > > > > > > > > > the
> > > > > > > > > > > > > > tiering
> > > > > > > > > > > > > > > > task is lagging or for data that is below
> the log
> > > > > start
> > > > > > > > offset.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 2. When does a segment become eligible to be
> > > tiered?
> > > > > > Is it
> > > > > > > > as
> > > > > > > > > > soon as
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > segment is rolled and the end offset is less
> > > than the
> > > > > > last
> > > > > > > > > > stable
> > > > > > > > > > > > > > offset as
> > > > > > > > > > > > > > > > mentioned in the KIP? I wonder if we need to
> > > consider
> > > > > > other
> > > > > > > > > > > > > parameters
> > > > > > > > > > > > > > too,
> > > > > > > > > > > > > > > > like the highwatermark so that we are
> guaranteed
> > > that
> > > > > > what
> > > > > > > > we
> > > > > > > > > > are
> > > > > > > > > > > > > > tiering
> > > > > > > > > > > > > > > > has been committed to the log and accepted
> by the
> > > > > ISR.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 3. The section on "Follower Fetch Scenarios"
> is
> > > > > useful
> > > > > > but
> > > > > > > > is
> > > > > > > > > > a bit
> > > > > > > > > > > > > > > > difficult to parse at the moment. It would be
> > > useful
> > > > > to
> > > > > > > > > > summarize the
> > > > > > > > > > > > > > > > changes we need in the ReplicaFetcher.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 4. Related to the above, it's a bit unclear
> how
> > > we
> > > > > are
> > > > > > > > > > planning on
> > > > > > > > > > > > > > > > restoring the producer state for a new
> replica.
> > > Could
> > > > > > you
> > > > > > > > > > expand on
> > > > > > > > > > > > > > that?
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 5. Similarly, it would be worth summarizing
> the
> > > > > > behavior on
> > > > > > > > > > unclean
> > > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > election. There are several scenarios to
> consider
> > > > > here:
> > > > > > > > data
> > > > > > > > > > loss
> > > > > > > > > > > > > from
> > > > > > > > > > > > > > > > local log, data loss from remote log, data
> loss
> > > from
> > > > > > > > metadata
> > > > > > > > > > topic,
> > > > > > > > > > > > > > etc.
> > > > > > > > > > > > > > > > It's worth describing these in detail.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 6. It would be useful to add details about
> how we
> > > > > plan
> > > > > > on
> > > > > > > > using
> > > > > > > > > > > > > > RocksDB in
> > > > > > > > > > > > > > > > the default implementation of
> > > > > > `RemoteLogMetadataManager`.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 7. For a READ_COMMITTED FetchRequest, how do
> we
> > > > > > retrieve
> > > > > > > > and
> > > > > > > > > > return
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > aborted transaction metadata?
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 8. The `LogSegmentData` class assumes that we
> > > have a
> > > > > > log
> > > > > > > > > > segment,
> > > > > > > > > > > > > > offset
> > > > > > > > > > > > > > > > index, time index, transaction index,
> producer
> > > > > > snapshot and
> > > > > > > > > > leader
> > > > > > > > > > > > > > epoch
> > > > > > > > > > > > > > > > index. How do we deal with cases where we do
> not
> > > have
> > > > > > one
> > > > > > > > or
> > > > > > > > > > more of
> > > > > > > > > > > > > > these?
> > > > > > > > > > > > > > > > For example, we may not have a transaction
> index
> > > or
> > > > > > > > producer
> > > > > > > > > > snapshot
> > > > > > > > > > > > > > for a
> > > > > > > > > > > > > > > > particular segment. The former is optional,
> and
> > > the
> > > > > > latter
> > > > > > > > is
> > > > > > > > > > only
> > > > > > > > > > > > > > kept for
> > > > > > > > > > > > > > > > up to the 3 latest segments.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > Dhruvil
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > On Mon, Sep 7, 2020 at 6:54 PM Harsha Ch <
> > > > > > > > harsha.ch@gmail.com>
> > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Hi All,
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > We are all working through the last meeting
> > > > > feedback.
> > > > > > > > I'll
> > > > > > > > > > cancel
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > tomorrow 's meeting and we can meanwhile
> > > continue
> > > > > our
> > > > > > > > > > discussion in
> > > > > > > > > > > > > > mailing
> > > > > > > > > > > > > > > > > list. We can start the regular meeting from
> > > next
> > > > > week
> > > > > > > > > > onwards.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Harsha
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > On Fri, Sep 04, 2020 at 8:41 AM, Satish
> > > Duggana <
> > > > > > > > > > > > > > satish.duggana@gmail.com
> > > > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > Hi Jun,
> > > > > > > > > > > > > > > > > > Thanks for your thorough review and
> comments.
> > > > > > Please
> > > > > > > > find
> > > > > > > > > > the
> > > > > > > > > > > > > > inline
> > > > > > > > > > > > > > > > > > replies below.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > 600. The topic deletion logic needs more
> > > details.
> > > > > > > > > > > > > > > > > > 600.1 The KIP mentions "The controller
> > > considers
> > > > > > the
> > > > > > > > topic
> > > > > > > > > > > > > > partition is
> > > > > > > > > > > > > > > > > > deleted only when it determines that
> there
> > > are no
> > > > > > log
> > > > > > > > > > segments
> > > > > > > > > > > > > for
> > > > > > > > > > > > > > that
> > > > > > > > > > > > > > > > > > topic partition by using RLMM". How is
> this
> > > done?
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > It uses RLMM#listSegments() returns all
> the
> > > > > > segments
> > > > > > > > for
> > > > > > > > > > the
> > > > > > > > > > > > > given
> > > > > > > > > > > > > > topic
> > > > > > > > > > > > > > > > > > partition.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > 600.2 "If the delete option is enabled
> then
> > > the
> > > > > > leader
> > > > > > > > > > will stop
> > > > > > > > > > > > > > RLM task
> > > > > > > > > > > > > > > > > > and stop processing and it sets all the
> > > remote
> > > > > log
> > > > > > > > segment
> > > > > > > > > > > > > > metadata of
> > > > > > > > > > > > > > > > > > that partition with a delete marker and
> > > publishes
> > > > > > them
> > > > > > > > to
> > > > > > > > > > RLMM."
> > > > > > > > > > > > > We
> > > > > > > > > > > > > > > > > > discussed this earlier. When a topic is
> being
> > > > > > deleted,
> > > > > > > > > > there may
> > > > > > > > > > > > > > not be a
> > > > > > > > > > > > > > > > > > leader for the deleted partition.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > This is a good point. As suggested in the
> > > > > meeting,
> > > > > > we
> > > > > > > > will
> > > > > > > > > > add a
> > > > > > > > > > > > > > separate
> > > > > > > > > > > > > > > > > > section for topic/partition deletion
> > > lifecycle
> > > > > and
> > > > > > this
> > > > > > > > > > scenario
> > > > > > > > > > > > > > will be
> > > > > > > > > > > > > > > > > > addressed.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > 601. Unclean leader election
> > > > > > > > > > > > > > > > > > 601.1 Scenario 1: new empty follower
> > > > > > > > > > > > > > > > > > After step 1, the follower restores up to
> > > offset
> > > > > > 3. So
> > > > > > > > why
> > > > > > > > > > does
> > > > > > > > > > > > > it
> > > > > > > > > > > > > > have
> > > > > > > > > > > > > > > > > > LE-2 <
> > > https://issues.apache.org/jira/browse/LE-2
> > > > > >
> > > > > > at
> > > > > > > > > > offset 5?
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > Nice catch. It was showing the leader
> epoch
> > > > > fetched
> > > > > > > > from
> > > > > > > > > > the
> > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > > storage. It should be shown with the
> > > truncated
> > > > > till
> > > > > > > > offset
> > > > > > > > > > 3.
> > > > > > > > > > > > > > Updated the
> > > > > > > > > > > > > > > > > > KIP.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > 601.2 senario 5: After Step 3, leader A
> has
> > > > > > > > inconsistent
> > > > > > > > > > data
> > > > > > > > > > > > > > between its
> > > > > > > > > > > > > > > > > > local and the tiered data. For example.
> > > offset 3
> > > > > > has
> > > > > > > > msg 3
> > > > > > > > > > LE-0
> > > > > > > > > > > > > > <https://issues.apache.org/jira/browse/LE-0>
> > > locally,
> > > > > > > > > > > > > > > > > > but msg 5 LE-1 <
> > > > > > > > https://issues.apache.org/jira/browse/LE-1>
> > > > > > > > > > in
> > > > > > > > > > > > > > the remote store. While it's ok for the unclean
> > > leader
> > > > > > > > > > > > > > > > > > to lose data, it should still return
> > > consistent
> > > > > > data,
> > > > > > > > > > whether
> > > > > > > > > > > > > it's
> > > > > > > > > > > > > > from
> > > > > > > > > > > > > > > > > > the local or the remote store.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > There is no inconsistency here as LE-0
> > > > > > > > > > > > > > <https://issues.apache.org/jira/browse/LE-0>
> > > offsets are
> > > > > > [0,
> > > > > > > > 4]
> > > > > > > > > > and LE-2
> > > > > > > > > > > > > > <https://issues.apache.org/jira/browse/LE-2>:
> > > > > > > > > > > > > > > > > > [5, ]. It will always get the right
> records
> > > for
> > > > > the
> > > > > > > > given
> > > > > > > > > > offset
> > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > leader epoch. In case of remote, RSM is
> > > invoked
> > > > > to
> > > > > > get
> > > > > > > > the
> > > > > > > > > > remote
> > > > > > > > > > > > > > log
> > > > > > > > > > > > > > > > > > segment that contains the given offset
> with
> > > the
> > > > > > leader
> > > > > > > > > > epoch.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > 601.4 It seems that retention is based on
> > > > > > > > > > > > > > > > > > listRemoteLogSegments(TopicPartition
> > > > > > topicPartition,
> > > > > > > > long
> > > > > > > > > > > > > > leaderEpoch).
> > > > > > > > > > > > > > > > > > When there is an unclean leader election,
> > > it's
> > > > > > possible
> > > > > > > > > > for the
> > > > > > > > > > > > > new
> > > > > > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > > > to not to include certain epochs in its
> epoch
> > > > > > cache.
> > > > > > > > How
> > > > > > > > > > are
> > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > > segments associated with those epochs
> being
> > > > > > cleaned?
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > That is a good point. This leader will
> also
> > > > > > cleanup the
> > > > > > > > > > epochs
> > > > > > > > > > > > > > earlier to
> > > > > > > > > > > > > > > > > > its start leader epoch and delete those
> > > segments.
> > > > > > It
> > > > > > > > gets
> > > > > > > > > > the
> > > > > > > > > > > > > > earliest
> > > > > > > > > > > > > > > > > > epoch for a partition and starts deleting
> > > > > segments
> > > > > > from
> > > > > > > > > > that
> > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > > epoch.
> > > > > > > > > > > > > > > > > > We need one more API in RLMM to get the
> > > earliest
> > > > > > leader
> > > > > > > > > > epoch.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > 601.5 The KIP discusses the handling of
> > > unclean
> > > > > > leader
> > > > > > > > > > elections
> > > > > > > > > > > > > > for user
> > > > > > > > > > > > > > > > > > topics. What about unclean leader
> elections
> > > on
> > > > > > > > > > > > > > > > > > __remote_log_segment_metadata?
> > > > > > > > > > > > > > > > > > This is the same as other system topics
> like
> > > > > > > > > > consumer_offsets,
> > > > > > > > > > > > > > > > > > __transaction_state topics. As discussed
> in
> > > the
> > > > > > > > meeting,
> > > > > > > > > > we will
> > > > > > > > > > > > > > add the
> > > > > > > > > > > > > > > > > > behavior of __remote_log_segment_metadata
> > > topic’s
> > > > > > > > unclean
> > > > > > > > > > leader
> > > > > > > > > > > > > > > > > > truncation.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > 602. It would be useful to clarify the
> > > > > limitations
> > > > > > in
> > > > > > > > the
> > > > > > > > > > initial
> > > > > > > > > > > > > > > > > release.
> > > > > > > > > > > > > > > > > > The KIP mentions not supporting compacted
> > > topics.
> > > > > > What
> > > > > > > > > > about JBOD
> > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > changing the configuration of a topic
> from
> > > delete
> > > > > > to
> > > > > > > > > > compact
> > > > > > > > > > > > > after
> > > > > > > > > > > > > > > > > remote.
> > > > > > > > > > > > > > > > > > log. storage. enable (
> > > > > > > > http://remote.log.storage.enable/
> > > > > > > > > > ) is
> > > > > > > > > > > > > > enabled?
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > This was updated in the KIP earlier.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > 603. RLM leader tasks:
> > > > > > > > > > > > > > > > > > 603.1"It checks for rolled over
> LogSegments
> > > > > (which
> > > > > > have
> > > > > > > > > > the last
> > > > > > > > > > > > > > message
> > > > > > > > > > > > > > > > > > offset less than last stable offset of
> that
> > > topic
> > > > > > > > > > partition) and
> > > > > > > > > > > > > > copies
> > > > > > > > > > > > > > > > > > them along with their
> offset/time/transaction
> > > > > > indexes
> > > > > > > > and
> > > > > > > > > > leader
> > > > > > > > > > > > > > epoch
> > > > > > > > > > > > > > > > > > cache to the remote tier." It needs to
> copy
> > > the
> > > > > > > > producer
> > > > > > > > > > snapshot
> > > > > > > > > > > > > > too.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > Right. It copies producer snapshots too
> as
> > > > > > mentioned in
> > > > > > > > > > > > > > LogSegmentData.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > 603.2 "Local logs are not cleaned up till
> > > those
> > > > > > > > segments
> > > > > > > > > > are
> > > > > > > > > > > > > copied
> > > > > > > > > > > > > > > > > > successfully to remote even though their
> > > > > retention
> > > > > > > > > > time/size is
> > > > > > > > > > > > > > reached"
> > > > > > > > > > > > > > > > > > This seems weird. If the tiering stops
> > > because
> > > > > the
> > > > > > > > remote
> > > > > > > > > > store
> > > > > > > > > > > > > is
> > > > > > > > > > > > > > not
> > > > > > > > > > > > > > > > > > available, we don't want the local data
> to
> > > grow
> > > > > > > > forever.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > It was clarified in the discussion that
> the
> > > > > > comment was
> > > > > > > > > > more
> > > > > > > > > > > > > about
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > local storage goes beyond the
> log.retention.
> > > The
> > > > > > above
> > > > > > > > > > statement
> > > > > > > > > > > > > > is about
> > > > > > > > > > > > > > > > > > local.log.retention but not for the
> complete
> > > > > > > > > > log.retention. When
> > > > > > > > > > > > > it
> > > > > > > > > > > > > > > > > > reaches the log.retention then it will
> > > delete the
> > > > > > local
> > > > > > > > > > logs even
> > > > > > > > > > > > > > though
> > > > > > > > > > > > > > > > > > those are not copied to remote storage.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > 604. "RLM maintains a bounded
> cache(possibly
> > > LRU)
> > > > > > of
> > > > > > > > the
> > > > > > > > > > index
> > > > > > > > > > > > > > files of
> > > > > > > > > > > > > > > > > > remote log segments to avoid multiple
> index
> > > > > fetches
> > > > > > > > from
> > > > > > > > > > the
> > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > > storage. These indexes can be used in the
> > > same
> > > > > way
> > > > > > as
> > > > > > > > local
> > > > > > > > > > > > > segment
> > > > > > > > > > > > > > > > > > indexes are used." Could you provide more
> > > details
> > > > > > on
> > > > > > > > this?
> > > > > > > > > > Are
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > indexes
> > > > > > > > > > > > > > > > > > cached in memory or on disk? If on disk,
> > > where
> > > > > are
> > > > > > they
> > > > > > > > > > stored?
> > > > > > > > > > > > > > Are the
> > > > > > > > > > > > > > > > > > cached indexes bound by a certain size?
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > These are cached on disk and stored in
> > > log.dir
> > > > > > with a
> > > > > > > > name
> > > > > > > > > > > > > > > > > > “__remote_log_index_cache”. They are
> bound
> > > by the
> > > > > > total
> > > > > > > > > > size.
> > > > > > > > > > > > > This
> > > > > > > > > > > > > > will
> > > > > > > > > > > > > > > > > be
> > > > > > > > > > > > > > > > > > exposed as a user configuration,
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > 605. BuildingRemoteLogAux
> > > > > > > > > > > > > > > > > > 605.1 In this section, two options are
> > > listed.
> > > > > > Which
> > > > > > > > one is
> > > > > > > > > > > > > chosen?
> > > > > > > > > > > > > > > > > > Option-2, updated the KIP.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > 605.2 In option 2, it says "Build the
> local
> > > > > leader
> > > > > > > > epoch
> > > > > > > > > > cache by
> > > > > > > > > > > > > > cutting
> > > > > > > > > > > > > > > > > > the leader epoch sequence received from
> > > remote
> > > > > > storage
> > > > > > > > to
> > > > > > > > > > [LSO,
> > > > > > > > > > > > > > ELO].
> > > > > > > > > > > > > > > > > (LSO
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > = log start offset)." We need to do the
> same
> > > > > thing
> > > > > > for
> > > > > > > > the
> > > > > > > > > > > > > producer
> > > > > > > > > > > > > > > > > > snapshot. However, it's hard to cut the
> > > producer
> > > > > > > > snapshot
> > > > > > > > > > to an
> > > > > > > > > > > > > > earlier
> > > > > > > > > > > > > > > > > > offset. Another option is to simply take
> the
> > > > > > lastOffset
> > > > > > > > > > from the
> > > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > > segment and use that as the starting
> fetch
> > > offset
> > > > > > in
> > > > > > > > the
> > > > > > > > > > > > > follower.
> > > > > > > > > > > > > > This
> > > > > > > > > > > > > > > > > > avoids the need for cutting.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > Right, this was mentioned in the
> > > “transactional
> > > > > > > > support”
> > > > > > > > > > section
> > > > > > > > > > > > > > about
> > > > > > > > > > > > > > > > > > adding these details.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > 606. ListOffsets: Since we need a version
> > > bump,
> > > > > > could
> > > > > > > > you
> > > > > > > > > > > > > document
> > > > > > > > > > > > > > it
> > > > > > > > > > > > > > > > > > under a protocol change section?
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > Sure, we will update the KIP.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > 607. "LogStartOffset of a topic can
> point to
> > > > > > either of
> > > > > > > > > > local
> > > > > > > > > > > > > > segment or
> > > > > > > > > > > > > > > > > > remote segment but it is initialised and
> > > > > > maintained in
> > > > > > > > the
> > > > > > > > > > Log
> > > > > > > > > > > > > > class like
> > > > > > > > > > > > > > > > > > now. This is already maintained in `Log`
> > > class
> > > > > > while
> > > > > > > > > > loading the
> > > > > > > > > > > > > > logs and
> > > > > > > > > > > > > > > > > > it can also be fetched from
> > > > > > RemoteLogMetadataManager."
> > > > > > > > > > What will
> > > > > > > > > > > > > > happen
> > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > the existing logic (e.g. log recovery)
> that
> > > > > > currently
> > > > > > > > > > depends on
> > > > > > > > > > > > > > > > > > logStartOffset but assumes it's local?
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > They use a field called
> localLogStartOffset
> > > which
> > > > > > is
> > > > > > > > the
> > > > > > > > > > local
> > > > > > > > > > > > > log
> > > > > > > > > > > > > > start
> > > > > > > > > > > > > > > > > > offset..
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > 608. Handle expired remote segment: How
> does
> > > it
> > > > > > pick
> > > > > > > > up new
> > > > > > > > > > > > > > > > > logStartOffset
> > > > > > > > > > > > > > > > > > from deleteRecords?
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > Good point. This was not addressed in the
> > > KIP.
> > > > > Will
> > > > > > > > update
> > > > > > > > > > the
> > > > > > > > > > > > > KIP
> > > > > > > > > > > > > > on how
> > > > > > > > > > > > > > > > > > the RLM task handles this scenario.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > 609. RLMM message format:
> > > > > > > > > > > > > > > > > > 609.1 It includes both MaxTimestamp and
> > > > > > EventTimestamp.
> > > > > > > > > > Where
> > > > > > > > > > > > > does
> > > > > > > > > > > > > > it get
> > > > > > > > > > > > > > > > > > both since the message in the log only
> > > contains
> > > > > one
> > > > > > > > > > timestamp?
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > `EventTimeStamp` is the timestamp at
> which
> > > that
> > > > > > segment
> > > > > > > > > > metadata
> > > > > > > > > > > > > > event is
> > > > > > > > > > > > > > > > > > generated. This is more for audits.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > 609.2 If we change just the state (e.g.
> to
> > > > > > > > > > DELETE_STARTED), it
> > > > > > > > > > > > > > seems it's
> > > > > > > > > > > > > > > > > > wasteful to have to include all other
> fields
> > > not
> > > > > > > > changed.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > This is a good point. We thought about
> > > > > incremental
> > > > > > > > > > updates. But
> > > > > > > > > > > > > we
> > > > > > > > > > > > > > want
> > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > make sure all the events are in the
> expected
> > > > > order
> > > > > > and
> > > > > > > > take
> > > > > > > > > > > > > action
> > > > > > > > > > > > > > based
> > > > > > > > > > > > > > > > > > on the latest event. Will think through
> the
> > > > > > approaches
> > > > > > > > in
> > > > > > > > > > detail
> > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > update here.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > 609.3 Could you document which process
> makes
> > > the
> > > > > > > > following
> > > > > > > > > > > > > > transitions
> > > > > > > > > > > > > > > > > > DELETE_MARKED, DELETE_STARTED,
> > > DELETE_FINISHED?
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > Okay, will document more details.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > 610. remote.log.reader.max.pending.tasks:
> > > > > "Maximum
> > > > > > > > remote
> > > > > > > > > > log
> > > > > > > > > > > > > > reader
> > > > > > > > > > > > > > > > > > thread pool task queue size. If the task
> > > queue is
> > > > > > full,
> > > > > > > > > > broker
> > > > > > > > > > > > > > will stop
> > > > > > > > > > > > > > > > > > reading remote log segments." What does
> the
> > > > > broker
> > > > > > do
> > > > > > > > if
> > > > > > > > > > the
> > > > > > > > > > > > > queue
> > > > > > > > > > > > > > is
> > > > > > > > > > > > > > > > > > full?
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > It returns an error for this topic
> partition.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > 611. What do we return if the request
> > > > > offset/epoch
> > > > > > > > doesn't
> > > > > > > > > > exist
> > > > > > > > > > > > > > in the
> > > > > > > > > > > > > > > > > > following API?
> > > > > > > > > > > > > > > > > > RemoteLogSegmentMetadata
> > > > > > > > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > > > > > > > > > > topicPartition, long offset, int
> > > epochForOffset)
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > This returns null. But we prefer to
> update
> > > the
> > > > > > return
> > > > > > > > type
> > > > > > > > > > as
> > > > > > > > > > > > > > Optional
> > > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > return Empty if that does not exist.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > > > Satish.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > On Tue, Sep 1, 2020 at 9:45 AM Jun Rao <
> jun@
> > > > > > > > confluent.
> > > > > > > > > > io (
> > > > > > > > > > > > > > > > > > jun@confluent.io ) > wrote:
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >> Hi, Satish,
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >> Thanks for the updated KIP. Made another
> > > pass. A
> > > > > > few
> > > > > > > > more
> > > > > > > > > > > > > comments
> > > > > > > > > > > > > > > > > below.
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >> 600. The topic deletion logic needs more
> > > > > details.
> > > > > > > > > > > > > > > > > >> 600.1 The KIP mentions "The controller
> > > considers
> > > > > > the
> > > > > > > > topic
> > > > > > > > > > > > > > partition is
> > > > > > > > > > > > > > > > > >> deleted only when it determines that
> there
> > > are
> > > > > no
> > > > > > log
> > > > > > > > > > segments
> > > > > > > > > > > > > > for that
> > > > > > > > > > > > > > > > > >> topic partition by using RLMM". How is
> this
> > > > > done?
> > > > > > > > 600.2
> > > > > > > > > > "If the
> > > > > > > > > > > > > > delete
> > > > > > > > > > > > > > > > > >> option is enabled then the leader will
> stop
> > > RLM
> > > > > > task
> > > > > > > > and
> > > > > > > > > > stop
> > > > > > > > > > > > > > processing
> > > > > > > > > > > > > > > > > >> and it sets all the remote log segment
> > > metadata
> > > > > of
> > > > > > > > that
> > > > > > > > > > > > > partition
> > > > > > > > > > > > > > with a
> > > > > > > > > > > > > > > > > >> delete marker and publishes them to
> RLMM."
> > > We
> > > > > > > > discussed
> > > > > > > > > > this
> > > > > > > > > > > > > > earlier.
> > > > > > > > > > > > > > > > > When
> > > > > > > > > > > > > > > > > >> a topic is being deleted, there may not
> be a
> > > > > > leader
> > > > > > > > for
> > > > > > > > > > the
> > > > > > > > > > > > > > deleted
> > > > > > > > > > > > > > > > > >> partition.
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >> 601. Unclean leader election
> > > > > > > > > > > > > > > > > >> 601.1 Scenario 1: new empty follower
> > > > > > > > > > > > > > > > > >> After step 1, the follower restores up
> to
> > > offset
> > > > > > 3. So
> > > > > > > > > > why does
> > > > > > > > > > > > > > it have
> > > > > > > > > > > > > > > > > >> LE-2 <
> > > > > https://issues.apache.org/jira/browse/LE-2>
> > > > > > at
> > > > > > > > > > offset 5?
> > > > > > > > > > > > > > > > > >> 601.2 senario 5: After Step 3, leader A
> has
> > > > > > > > inconsistent
> > > > > > > > > > data
> > > > > > > > > > > > > > between
> > > > > > > > > > > > > > > > > its
> > > > > > > > > > > > > > > > > >> local and the tiered data. For example.
> > > offset 3
> > > > > > has
> > > > > > > > msg
> > > > > > > > > > 3 LE-0
> > > > > > > > > > > > > > <https://issues.apache.org/jira/browse/LE-0>
> > > locally,
> > > > > > > > > > > > > > > > > >> but msg 5 LE-1 <
> > > > > > > > > > https://issues.apache.org/jira/browse/LE-1> in
> > > > > > > > > > > > > > the remote store. While it's ok for the unclean
> > > leader
> > > > > > > > > > > > > > > > > >> to lose data, it should still return
> > > consistent
> > > > > > data,
> > > > > > > > > > whether
> > > > > > > > > > > > > > it's from
> > > > > > > > > > > > > > > > > >> the local or the remote store.
> > > > > > > > > > > > > > > > > >> 601.3 The follower picks up log start
> offset
> > > > > > using the
> > > > > > > > > > following
> > > > > > > > > > > > > > api.
> > > > > > > > > > > > > > > > > >> Suppose that we have 3 remote segments
> (LE,
> > > > > > > > > > SegmentStartOffset)
> > > > > > > > > > > > > > as (2,
> > > > > > > > > > > > > > > > > >> 10),
> > > > > > > > > > > > > > > > > >> (3, 20) and (7, 15) due to an unclean
> leader
> > > > > > election.
> > > > > > > > > > Using the
> > > > > > > > > > > > > > > > > following
> > > > > > > > > > > > > > > > > >> api will cause logStartOffset to go
> backward
> > > > > from
> > > > > > 20
> > > > > > > > to
> > > > > > > > > > 15. How
> > > > > > > > > > > > > > do we
> > > > > > > > > > > > > > > > > >> prevent that?
> > > > > > > > > > > > > > > > > >> earliestLogOffset(TopicPartition
> > > topicPartition,
> > > > > > int
> > > > > > > > > > > > > leaderEpoch)
> > > > > > > > > > > > > > 601.4
> > > > > > > > > > > > > > > > > It
> > > > > > > > > > > > > > > > > >> seems that retention is based on
> > > > > > > > > > > > > > > > > >> listRemoteLogSegments(TopicPartition
> > > > > > topicPartition,
> > > > > > > > long
> > > > > > > > > > > > > > leaderEpoch).
> > > > > > > > > > > > > > > > > >> When there is an unclean leader
> election,
> > > it's
> > > > > > > > possible
> > > > > > > > > > for the
> > > > > > > > > > > > > > new
> > > > > > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > > >> to not to include certain epochs in its
> > > epoch
> > > > > > cache.
> > > > > > > > How
> > > > > > > > > > are
> > > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > >> segments associated with those epochs
> being
> > > > > > cleaned?
> > > > > > > > > > 601.5 The
> > > > > > > > > > > > > KIP
> > > > > > > > > > > > > > > > > >> discusses the handling of unclean leader
> > > > > > elections for
> > > > > > > > > > user
> > > > > > > > > > > > > > topics. What
> > > > > > > > > > > > > > > > > >> about unclean leader elections on
> > > > > > > > > > > > > > > > > >> __remote_log_segment_metadata?
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >> 602. It would be useful to clarify the
> > > > > > limitations in
> > > > > > > > the
> > > > > > > > > > > > > initial
> > > > > > > > > > > > > > > > > release.
> > > > > > > > > > > > > > > > > >> The KIP mentions not supporting
> compacted
> > > > > topics.
> > > > > > What
> > > > > > > > > > about
> > > > > > > > > > > > > JBOD
> > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > >> changing the configuration of a topic
> from
> > > > > delete
> > > > > > to
> > > > > > > > > > compact
> > > > > > > > > > > > > after
> > > > > > > > > > > > > > > > > remote.
> > > > > > > > > > > > > > > > > >> log. storage. enable (
> > > > > > > > http://remote.log.storage.enable/
> > > > > > > > > > ) is
> > > > > > > > > > > > > > enabled?
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >> 603. RLM leader tasks:
> > > > > > > > > > > > > > > > > >> 603.1"It checks for rolled over
> LogSegments
> > > > > (which
> > > > > > > > have
> > > > > > > > > > the last
> > > > > > > > > > > > > > message
> > > > > > > > > > > > > > > > > >> offset less than last stable offset of
> that
> > > > > topic
> > > > > > > > > > partition) and
> > > > > > > > > > > > > > copies
> > > > > > > > > > > > > > > > > >> them along with their
> > > offset/time/transaction
> > > > > > indexes
> > > > > > > > and
> > > > > > > > > > leader
> > > > > > > > > > > > > > epoch
> > > > > > > > > > > > > > > > > >> cache to the remote tier." It needs to
> copy
> > > the
> > > > > > > > producer
> > > > > > > > > > > > > snapshot
> > > > > > > > > > > > > > too.
> > > > > > > > > > > > > > > > > >> 603.2 "Local logs are not cleaned up
> till
> > > those
> > > > > > > > segments
> > > > > > > > > > are
> > > > > > > > > > > > > > copied
> > > > > > > > > > > > > > > > > >> successfully to remote even though their
> > > > > retention
> > > > > > > > > > time/size is
> > > > > > > > > > > > > > reached"
> > > > > > > > > > > > > > > > > >> This seems weird. If the tiering stops
> > > because
> > > > > the
> > > > > > > > remote
> > > > > > > > > > store
> > > > > > > > > > > > > > is not
> > > > > > > > > > > > > > > > > >> available, we don't want the local data
> to
> > > grow
> > > > > > > > forever.
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >> 604. "RLM maintains a bounded
> cache(possibly
> > > > > LRU)
> > > > > > of
> > > > > > > > the
> > > > > > > > > > index
> > > > > > > > > > > > > > files of
> > > > > > > > > > > > > > > > > >> remote log segments to avoid multiple
> index
> > > > > > fetches
> > > > > > > > from
> > > > > > > > > > the
> > > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > >> storage. These indexes can be used in
> the
> > > same
> > > > > > way as
> > > > > > > > > > local
> > > > > > > > > > > > > > segment
> > > > > > > > > > > > > > > > > >> indexes are used." Could you provide
> more
> > > > > details
> > > > > > on
> > > > > > > > > > this? Are
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > indexes
> > > > > > > > > > > > > > > > > >> cached in memory or on disk? If on disk,
> > > where
> > > > > are
> > > > > > > > they
> > > > > > > > > > stored?
> > > > > > > > > > > > > > Are the
> > > > > > > > > > > > > > > > > >> cached indexes bound by a certain size?
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >> 605. BuildingRemoteLogAux
> > > > > > > > > > > > > > > > > >> 605.1 In this section, two options are
> > > listed.
> > > > > > Which
> > > > > > > > one
> > > > > > > > > > is
> > > > > > > > > > > > > > chosen?
> > > > > > > > > > > > > > > > > 605.2
> > > > > > > > > > > > > > > > > >> In option 2, it says "Build the local
> leader
> > > > > epoch
> > > > > > > > cache
> > > > > > > > > > by
> > > > > > > > > > > > > > cutting the
> > > > > > > > > > > > > > > > > >> leader epoch sequence received from
> remote
> > > > > > storage to
> > > > > > > > > > [LSO,
> > > > > > > > > > > > > ELO].
> > > > > > > > > > > > > > (LSO
> > > > > > > > > > > > > > > > > >> = log start offset)." We need to do the
> same
> > > > > thing
> > > > > > > > for the
> > > > > > > > > > > > > > producer
> > > > > > > > > > > > > > > > > >> snapshot. However, it's hard to cut the
> > > producer
> > > > > > > > snapshot
> > > > > > > > > > to an
> > > > > > > > > > > > > > earlier
> > > > > > > > > > > > > > > > > >> offset. Another option is to simply
> take the
> > > > > > > > lastOffset
> > > > > > > > > > from the
> > > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > >> segment and use that as the starting
> fetch
> > > > > offset
> > > > > > in
> > > > > > > > the
> > > > > > > > > > > > > > follower. This
> > > > > > > > > > > > > > > > > >> avoids the need for cutting.
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >> 606. ListOffsets: Since we need a
> version
> > > bump,
> > > > > > could
> > > > > > > > you
> > > > > > > > > > > > > > document it
> > > > > > > > > > > > > > > > > >> under a protocol change section?
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >> 607. "LogStartOffset of a topic can
> point to
> > > > > > either of
> > > > > > > > > > local
> > > > > > > > > > > > > > segment or
> > > > > > > > > > > > > > > > > >> remote segment but it is initialised and
> > > > > > maintained in
> > > > > > > > > > the Log
> > > > > > > > > > > > > > class
> > > > > > > > > > > > > > > > > like
> > > > > > > > > > > > > > > > > >> now. This is already maintained in `Log`
> > > class
> > > > > > while
> > > > > > > > > > loading the
> > > > > > > > > > > > > > logs
> > > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > >> it can also be fetched from
> > > > > > RemoteLogMetadataManager."
> > > > > > > > > > What will
> > > > > > > > > > > > > > happen
> > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > >> the existing logic (e.g. log recovery)
> that
> > > > > > currently
> > > > > > > > > > depends on
> > > > > > > > > > > > > > > > > >> logStartOffset but assumes it's local?
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >> 608. Handle expired remote segment: How
> > > does it
> > > > > > pick
> > > > > > > > up
> > > > > > > > > > new
> > > > > > > > > > > > > > > > > logStartOffset
> > > > > > > > > > > > > > > > > >> from deleteRecords?
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >> 609. RLMM message format:
> > > > > > > > > > > > > > > > > >> 609.1 It includes both MaxTimestamp and
> > > > > > > > EventTimestamp.
> > > > > > > > > > Where
> > > > > > > > > > > > > > does it
> > > > > > > > > > > > > > > > > get
> > > > > > > > > > > > > > > > > >> both since the message in the log only
> > > contains
> > > > > > one
> > > > > > > > > > timestamp?
> > > > > > > > > > > > > > 609.2 If
> > > > > > > > > > > > > > > > > we
> > > > > > > > > > > > > > > > > >> change just the state (e.g. to
> > > DELETE_STARTED),
> > > > > it
> > > > > > > > seems
> > > > > > > > > > it's
> > > > > > > > > > > > > > wasteful
> > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > >> have to include all other fields not
> > > changed.
> > > > > > 609.3
> > > > > > > > Could
> > > > > > > > > > you
> > > > > > > > > > > > > > document
> > > > > > > > > > > > > > > > > >> which process makes the following
> > > transitions
> > > > > > > > > > DELETE_MARKED,
> > > > > > > > > > > > > > > > > >> DELETE_STARTED, DELETE_FINISHED?
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >> 610.
> remote.log.reader.max.pending.tasks:
> > > > > "Maximum
> > > > > > > > remote
> > > > > > > > > > log
> > > > > > > > > > > > > > reader
> > > > > > > > > > > > > > > > > >> thread pool task queue size. If the task
> > > queue
> > > > > is
> > > > > > > > full,
> > > > > > > > > > broker
> > > > > > > > > > > > > > will stop
> > > > > > > > > > > > > > > > > >> reading remote log segments." What does
> the
> > > > > > broker do
> > > > > > > > if
> > > > > > > > > > the
> > > > > > > > > > > > > > queue is
> > > > > > > > > > > > > > > > > >> full?
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >> 611. What do we return if the request
> > > > > offset/epoch
> > > > > > > > > > doesn't exist
> > > > > > > > > > > > > > in the
> > > > > > > > > > > > > > > > > >> following API?
> > > > > > > > > > > > > > > > > >> RemoteLogSegmentMetadata
> > > > > > > > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > > > > > > > > > >> topicPartition, long offset, int
> > > epochForOffset)
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >> Jun
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >> On Mon, Aug 31, 2020 at 11:19 AM Satish
> > > Duggana
> > > > > <
> > > > > > > > satish.
> > > > > > > > > > > > > duggana@
> > > > > > > > > > > > > > > > > gmail. com
> > > > > > > > > > > > > > > > > >> ( satish.duggana@gmail.com ) > wrote:
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>> KIP is updated with
> > > > > > > > > > > > > > > > > >>> - Remote log segment metadata topic
> message
> > > > > > > > > > format/schema.
> > > > > > > > > > > > > > > > > >>> - Added remote log segment metadata
> state
> > > > > > > > transitions and
> > > > > > > > > > > > > > explained how
> > > > > > > > > > > > > > > > > >>> the deletion of segments is handled,
> > > including
> > > > > > the
> > > > > > > > case
> > > > > > > > > > of
> > > > > > > > > > > > > > partition
> > > > > > > > > > > > > > > > > >>> deletions.
> > > > > > > > > > > > > > > > > >>> - Added a few more limitations in the
> "Non
> > > > > goals"
> > > > > > > > > > section.
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>> Thanks,
> > > > > > > > > > > > > > > > > >>> Satish.
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>> On Thu, Aug 27, 2020 at 12:42 AM
> Harsha Ch
> > > <
> > > > > > harsha.
> > > > > > > > ch@
> > > > > > > > > > > > > gmail.
> > > > > > > > > > > > > > com (
> > > > > > > > > > > > > > > > > >>> harsha.ch@gmail.com ) > wrote:
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>> Updated the KIP with Meeting Notes
> section
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>> https:/ / cwiki. apache. org/
> confluence/
> > > > > > display/
> > > > > > > > KAFKA/
> > > > > > > > > > > > > > > > > KIP-405 <
> > > > > > https://issues.apache.org/jira/browse/KIP-405>
> > > > > > > > > > > > > >
> > > > > > %3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> > > > > > > > > > > > > > > > > >>> (
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > >
> > > > > > > >
> > > > > >
> > > > >
> > >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-405%3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> > > > > > > > > > > > > > > > > >>> )
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>> On Tue, Aug 25, 2020 at 1:03 PM Jun
> Rao <
> > > jun@
> > > > > > > > > > confluent. io
> > > > > > > > > > > > > (
> > > > > > > > > > > > > > > > > >>>> jun@confluent.io ) > wrote:
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>> Hi, Harsha,
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>> Thanks for the summary. Could you
> add the
> > > > > > summary
> > > > > > > > and
> > > > > > > > > > the
> > > > > > > > > > > > > > recording
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>> link to
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>> the last section of
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>> https:/ / cwiki. apache. org/
> confluence/
> > > > > > display/
> > > > > > > > KAFKA/
> > > > > > > > > > > > > > > > > Kafka+Improvement+Proposals
> > > > > > > > > > > > > > > > > >>> (
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > >
> > > > > > > >
> > > > > >
> > > > >
> > >
> https://cwiki.apache.org/confluence/display/KAFKA/Kafka+Improvement+Proposals
> > > > > > > > > > > > > > > > > >>> )
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>> ?
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>> Jun
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>> On Tue, Aug 25, 2020 at 11:12 AM
> Harsha
> > > > > > > > Chintalapani <
> > > > > > > > > > kafka@
> > > > > > > > > > > > > > > > > harsha. io (
> > > > > > > > > > > > > > > > > >>>>> kafka@harsha.io ) > wrote:
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>> Thanks everyone for attending the
> > > meeting
> > > > > > today.
> > > > > > > > > > > > > > > > > >>>>>> Here is the recording
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>> https:/ / drive. google. com/ file/ d/
> > > > > > > > > > > > > > > > > 14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/
> > > view?usp=sharing
> > > > > > > > > > > > > > > > > >>> (
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > >
> > > > > > > >
> > > > > >
> > > > >
> > >
> https://drive.google.com/file/d/14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/view?usp=sharing
> > > > > > > > > > > > > > > > > >>> )
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>> Notes:
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>> 1. KIP is updated with follower
> fetch
> > > > > > protocol and
> > > > > > > > > > ready to
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>> reviewed
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>> 2. Satish to capture schema of
> internal
> > > > > > metadata
> > > > > > > > > > topic in
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > KIP
> > > > > > > > > > > > > > > > > >>>>>> 3. We will update the KIP with
> details
> > > of
> > > > > > > > different
> > > > > > > > > > cases
> > > > > > > > > > > > > > > > > >>>>>> 4. Test plan will be captured in a
> doc
> > > and
> > > > > > will
> > > > > > > > add
> > > > > > > > > > to the
> > > > > > > > > > > > > KIP
> > > > > > > > > > > > > > > > > >>>>>> 5. Add a section "Limitations" to
> > > capture
> > > > > the
> > > > > > > > > > capabilities
> > > > > > > > > > > > > > that
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>> will
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>> be
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>> introduced with this KIP and what
> will
> > > not
> > > > > be
> > > > > > > > covered
> > > > > > > > > > in
> > > > > > > > > > > > > this
> > > > > > > > > > > > > > KIP.
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>> Please add to it I missed anything.
> Will
> > > > > > produce a
> > > > > > > > > > formal
> > > > > > > > > > > > > > meeting
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>> notes
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>> from next meeting onwards.
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>> Thanks,
> > > > > > > > > > > > > > > > > >>>>>> Harsha
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>> On Mon, Aug 24, 2020 at 9:42 PM,
> Ying
> > > Zheng
> > > > > <
> > > > > > > > yingz@
> > > > > > > > > > uber.
> > > > > > > > > > > > > > com.
> > > > > > > > > > > > > > > > > invalid (
> > > > > > > > > > > > > > > > > >>>>>> yingz@uber.com.invalid ) > wrote:
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> We did some basic feature tests at
> > > Uber.
> > > > > The
> > > > > > test
> > > > > > > > > > cases and
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>> results are
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> shared in this google doc:
> > > > > > > > > > > > > > > > > >>>>>>> https:/ / docs. google. com/
> > > spreadsheets/
> > > > > > d/ (
> > > > > > > > > > > > > > > > > >>>>>>>
> > > https://docs.google.com/spreadsheets/d/ )
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >
> > > > > 1XhNJqjzwXvMCcAOhEH0sSXU6RTvyoSf93DHF-YMfGLk/edit?usp=sharing
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> The performance test results were
> > > already
> > > > > > shared
> > > > > > > > in
> > > > > > > > > > the KIP
> > > > > > > > > > > > > > last
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>> month.
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> On Mon, Aug 24, 2020 at 11:10 AM
> > > Harsha Ch
> > > > > <
> > > > > > > > harsha.
> > > > > > > > > > ch@
> > > > > > > > > > > > > > gmail.
> > > > > > > > > > > > > > > > > com (
> > > > > > > > > > > > > > > > > >>>>>>> harsha.ch@gmail.com ) >
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>> wrote:
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> "Understand commitments towards
> driving
> > > > > > design &
> > > > > > > > > > > > > > implementation of
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>> the
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>> KIP
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> further and how it aligns with
> > > participant
> > > > > > > > interests
> > > > > > > > > > in
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>> contributing to
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>> the
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> efforts (ex: in the context of
> Uber’s
> > > Q3/Q4
> > > > > > > > > > roadmap)." What
> > > > > > > > > > > > > > is that
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>> about?
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> On Mon, Aug 24, 2020 at 11:05 AM
> > > Kowshik
> > > > > > > > Prakasam <
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>> kprakasam@ confluent. io (
> > > > > > kprakasam@confluent.io
> > > > > > > > ) >
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> wrote:
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> Hi Harsha,
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> The following google doc contains a
> > > > > proposal
> > > > > > for
> > > > > > > > > > temporary
> > > > > > > > > > > > > > agenda
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>> for
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>> the
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> KIP-405 <
> > > > > > > > > > https://issues.apache.org/jira/browse/KIP-405> <
> > > > > > > > > > > > > > https:/ / issues. apache. org/ jira/ browse/
> KIP-405
> > > > > > > > > > > > > > <https://issues.apache.org/jira/browse/KIP-405>
> (
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > https://issues.apache.org/jira/browse/KIP-405 )
> > > > > > > > >
> > > > > > > > > > sync
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>> meeting
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> tomorrow:
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> https:/ / docs. google. com/
> document/
> > > d/ (
> > > > > > > > > > > > > > > > > >>>>>>>
> https://docs.google.com/document/d/ )
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > 1pqo8X5LU8TpwfC_iqSuVPezhfCfhGkbGN2TqiPA3LBU/edit
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> .
> > > > > > > > > > > > > > > > > >>>>>>> Please could you add it to the
> Google
> > > > > > calendar
> > > > > > > > > > invite?
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> Thank you.
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> Cheers,
> > > > > > > > > > > > > > > > > >>>>>>> Kowshik
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> On Thu, Aug 20, 2020 at 10:58 AM
> > > Harsha Ch
> > > > > <
> > > > > > > > harsha.
> > > > > > > > > > ch@
> > > > > > > > > > > > > > gmail.
> > > > > > > > > > > > > > > > > com (
> > > > > > > > > > > > > > > > > >>>>>>> harsha.ch@gmail.com ) >
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>> wrote:
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> Hi All,
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> Scheduled a meeting for Tuesday
> 9am -
> > > 10am.
> > > > > > I can
> > > > > > > > > > record
> > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>> upload for
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> community to be able to follow the
> > > > > > discussion.
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> Jun, please add the required folks
> on
> > > > > > confluent
> > > > > > > > side.
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> Thanks,
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> Harsha
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> On Thu, Aug 20, 2020 at 12:33 AM,
> > > Alexandre
> > > > > > > > Dupriez <
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>> alexandre.dupriez@
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> gmail. com ( http://gmail.com/ ) >
> > > wrote:
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> Hi Jun,
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> Many thanks for your initiative.
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> If you like, I am happy to attend
> at
> > > the
> > > > > > time you
> > > > > > > > > > > > > suggested.
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> Many thanks,
> > > > > > > > > > > > > > > > > >>>>>>> Alexandre
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> Le mer. 19 août 2020 à 22:00,
> Harsha
> > > Ch <
> > > > > > > > harsha. ch@
> > > > > > > > > > > > > > gmail. com (
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>> harsha.
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> ch@ gmail. com ( ch@gmail.com ) )
> > a
> > > > > écrit
> > > > > > :
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> Hi Jun,
> > > > > > > > > > > > > > > > > >>>>>>> Thanks. This will help a lot.
> Tuesday
> > > will
> > > > > > work
> > > > > > > > for
> > > > > > > > > > us.
> > > > > > > > > > > > > > > > > >>>>>>> -Harsha
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> On Wed, Aug 19, 2020 at 1:24 PM Jun
> > > Rao <
> > > > > > jun@
> > > > > > > > > > confluent.
> > > > > > > > > > > > > > io (
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>> jun@
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> confluent. io (
> http://confluent.io/
> > > ) ) >
> > > > > > > > wrote:
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> Hi, Satish, Ying, Harsha,
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> Do you think it would be useful to
> > > have a
> > > > > > regular
> > > > > > > > > > virtual
> > > > > > > > > > > > > > meeting
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>> to
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> discuss this KIP? The goal of the
> > > meeting
> > > > > > will be
> > > > > > > > > > sharing
> > > > > > > > > > > > > > > > > >>>>>>> design/development progress and
> > > discussing
> > > > > > any
> > > > > > > > open
> > > > > > > > > > issues
> > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> accelerate
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> this KIP. If so, will every Tuesday
> > > (from
> > > > > > next
> > > > > > > > week)
> > > > > > > > > > > > > 9am-10am
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> PT
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> work for you? I can help set up a
> Zoom
> > > > > > meeting,
> > > > > > > > > > invite
> > > > > > > > > > > > > > everyone who
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> might
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> be interested, have it recorded and
> > > shared,
> > > > > > etc.
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> Thanks,
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> Jun
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> On Tue, Aug 18, 2020 at 11:01 AM
> Satish
> > > > > > Duggana <
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> satish. duggana@ gmail. com (
> satish.
> > > > > > duggana@
> > > > > > > > > > gmail. com
> > > > > > > > > > > > > (
> > > > > > > > > > > > > > > > > >>>>>>> satish.duggana@gmail.com ) ) >
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> wrote:
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> Hi Kowshik,
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> Thanks for looking into the KIP and
> > > sending
> > > > > > your
> > > > > > > > > > comments.
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > > >>>>>>> 5001. Under the section "Follower
> fetch
> > > > > > protocol
> > > > > > > > in
> > > > > > > > > > > > > detail",
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > >>>>>>> next-local-offset is the offset
> upto
> > > which
> > > > > > the
> > > > > > > > > > segments are
> > > > > > > > > > > > > > copied
> > > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > >
> > > > > >
> > > > >
> > >
>

Re: [DISCUSS] KIP-405: Kafka Tiered Storage

[Satish Duggana <sa...@gmail.com>]

Hi Jun,

Thanks for your comments. Please find the inline replies below.
Several of these were discussed/clarified in our last discussion.

6000. Since we are returning new error codes, we need to bump up the
protocol version for Fetch request. Also, it will be useful to document all
new error codes and whether they are retriable or not.
This previous comment doesn't seem to be addressed.

Updated KIP on fetch protocol and error code.

9110. flat_file_format: Could you define the serialized representation for
each field in the header?

Added the serialized representation types in the KIP.

9111. RPM has the following 2 steps.
"1. The controller publishes delete_partition_marked event to say that the
partition is marked for deletion. There can be multiple events published
when the controller restarts or failover and this event will be
deduplicated by RPM.
2. RPM receives the delete_partition_marked and processes it if it is not
yet processed earlier."
What triggers RPM to read __remote_log_metadata? Is RPM part of the default
RLMM implementation or is it meant for any RLMM implementation?

RPM(or RPRM) is only for the default RLMM implementation. RPM receives
the delete_partition_marked events from RLMM and acts on them. Updated
KIP with more details.

9112. remote.log.manager.task.retry.backoff.ms: It would be useful to make
it clear in the comment that this is for the initial retry backoff.

Updated the KIP.

9113. RLMM:
9113.1 updateRemoteLogSegmentMetadata(): This comment needs to be updated.

Updated javadoc of this method.

9113.2 Should RemoteLogSegmentMetadataUpdate include a leadeEpoch field
since all other update events have leaderEpoch?

+1 to have that,  updated the KIP.

9113.3 Could we rename RemotePartitionState to RemotePartitionDeleteState
to make it clear this is for deletion?

Sure, updated the KIP.

9113.4 Could we rename RemoteLogState to RemoteLogSegmentState to make it
clear this is for segment?

Sure, Updated the KIP.

9114.Upgrade:
9114.1 It seems that we require message format > 0.11 for turning on the
remote store feature.

9114.2 It's not clear to me why remote.log.storage.system.enable needs to
be set to true before bumping up inter.broker.protocol.version.

Agree that based on our discussion, this is not required. Upgrade
notes is updated.

9114.3 "If the topic-id is not received in the LeaderAndIsr request then
remote log storage will not start. But it will log an error message in the
log. One way to address this is to do a rolling restart of that broker, so
that the leader will be moved to another broker and the controller will
send LeaderAndIsr with the registered topic-id." Why is this needed? With
KIP-516, after upgrading to the latest protocol, topicIds are auto created.

I thought there may be edge cases of not receiving topic-id but you
clarified in the meeting that won’t be the case. I agree that it is
not needed.

9115. testing: Could you comment on how we plan to do integration and
system tests? Do we plan to include, for example, an in-memory
implementation of RSM?

For integration tests, we can have file based RSM that we have. For
system tests, we can have a single node HDFS cluster in one of the
containers and use HDFS RSM implementation.

9116. There is still a todo for the message formatter.

Updated the KIP with the format.


Satish.


On Tue, 12 Jan 2021 at 07:07, Jun Rao <ju...@confluent.io> wrote:
>
> Hi, Satish,
>
> Thanks for the reply. A few more followup comments.
>
> 6000. Since we are returning new error codes, we need to bump up the
> protocol version for Fetch request. Also, it will be useful to document all
> new error codes and whether they are retriable or not.
> This previous comment doesn't seem to be addressed.
>
> 9110. flat_file_format: Could you define the serialized representation for
> each field in the header?
>
> 9111. RPM has the following 2 steps.
> "1. The controller publishes delete_partition_marked event to say that the
> partition is marked for deletion. There can be multiple events published
> when the controller restarts or failover and this event will be
> deduplicated by RPM.
> 2. RPM receives the delete_partition_marked and processes it if it is not
> yet processed earlier."
> What triggers RPM to read __remote_log_metadata? Is RPM part of the default
> RLMM implementation or is it meant for any RLMM implementation?
>
> 9112. remote.log.manager.task.retry.backoff.ms: It would be useful to make
> it clear in the comment that this is for the initial retry backoff.
>
> 9113. RLMM:
> 9113.1 updateRemoteLogSegmentMetadata(): This comment needs to be updated.
> 9113.2 Should RemoteLogSegmentMetadataUpdate include a leadeEpoch field
> since all other update events have leaderEpoch?
> 9113.3 Could we rename RemotePartitionState to RemotePartitionDeleteState
> to make it clear this is for deletion?
> 9113.4 Could we rename RemoteLogState to RemoteLogSegmentState to make it
> clear this is for segment?
>
> 9114.Upgrade:
> 9114.1 It seems that we require message format > 0.11 for turning on the
> remote store feature.
> 9114.2 It's not clear to me why remote.log.storage.system.enable needs to
> be set to true before bumping up inter.broker.protocol.version.
> 9114.3 "If the topic-id is not received in the LeaderAndIsr request then
> remote log storage will not start. But it will log an error message in the
> log. One way to address this is to do a rolling restart of that broker, so
> that the leader will be moved to another broker and the controller will
> send LeaderAndIsr with the registered topic-id." Why is this needed? With
> KIP-516, after upgrading to the latest protocol, topicIds are auto created.
>
> 9115. testing: Could you comment on how we plan to do integration and
> system tests? Do we plan to include, for example, an in-memory
> implementation of RSM?
>
> 9116. There is still a todo for the message formatter.
>
> Jun
>
> On Sat, Jan 9, 2021 at 2:04 AM Satish Duggana <sa...@gmail.com>
> wrote:
>
> > Hi Jun,
> > Thanks for your comments. Please find the inline replies below.
> >
> > 6022. For packages used for server plugins, the convention is to
> > use org.apache.kafka.server. See java-based Authorizer as an example.
> >
> > Sure, ‘org.apache.kafka.common.log.remote.storage’ renamed to
> > ‘org.apache.kafka.server.log.remote.storage’.  Updated in the KIP.
> >
> > 9100. Do we need DeletePartitionStateRecord in flat_file_format? The flat
> > file captures the state of the remote segments. After a partition is
> > deleted, it seems that we just need to remove the partitions's remote
> > segments from the flat file.
> >
> > DeletePartitionState might not yet have been processed by RPM and not
> > completed. We  will not have  that in flat  file format  once it
> > reaches DELETE_PARTITION_FINISHED state.
> >
> > 9101. Upgrade: It will be useful to allow direct upgrade from an old
> > version. It seems that's doable. One can just do the normal upgrade first
> > and wait enough time (for producer snapshots to be built), and then enable
> > remote storage.
> >
> > Upgrade notes updates in the KIP.
> >
> > 9102. RemotePartitionRemover(RPM) process: Is it true that RPM starts
> > tracking the remote segments when RLMM.onPartitionLeadershipChanges() is
> > called with the broker being the leader for __remote_log_metadata
> > partition? If so, could we document it?
> >
> > The current plan is to have that as part of RLMM and RPM uses that to
> > get the remote segments list. I will add this detail in the respective
> > sections.
> >
> > Satish.
> >
> > On Wed, 16 Dec 2020 at 23:55, Jun Rao <ju...@confluent.io> wrote:
> > >
> > > Hi, Satish,
> > >
> > > Thanks for the reply. A few more followup comments.
> > >
> > > 6022. For packages used for server plugins, the convention is to
> > > use org.apache.kafka.server. See java-based Authorizer as an example.
> > >
> > > 9100. Do we need DeletePartitionStateRecord in flat_file_format? The flat
> > > file captures the state of the remote segments. After a partition is
> > > deleted, it seems that we just need to remove the partitions's remote
> > > segments from the flat file.
> > >
> > > 9101. Upgrade: It will be useful to allow direct upgrade from an old
> > > version. It seems that's doable. One can just do the normal upgrade first
> > > and wait enough time (for producer snapshots to be built), and then
> > enable
> > > remote storage.
> > >
> > > 9102. RemotePartitionRemover(RPM) process: Is it true that RPM starts
> > > tracking the remote segments when RLMM.onPartitionLeadershipChanges() is
> > > called with the broker being the leader for __remote_log_metadata
> > > partition? If so, could we document it?
> > >
> > > Jun
> > >
> > > On Tue, Dec 15, 2020 at 8:47 AM Kowshik Prakasam <kprakasam@confluent.io
> > >
> > > wrote:
> > >
> > > > Hi Satish,
> > > >
> > > > Thanks for the updates! A few more comments below.
> > > >
> > > > 9001. Under the "Upgrade" section, there is a line mentioning:
> > "Upgrade the
> > > > existing Kafka cluster to 2.7 version and allow this to run for the log
> > > > retention of user topics that you want to enable tiered storage. This
> > will
> > > > allow all the topics to have the producer snapshots generated for each
> > log
> > > > segment." -- Which associated change in AK were you referring to here?
> > Is
> > > > it: https://github.com/apache/kafka/pull/7929 ? It seems like I don't
> > see
> > > > it in the 2.7 release branch yet, here is the link:
> > > > https://github.com/apache/kafka/commits/2.7.
> > > >
> > > > 9002. Under the "Upgrade" section, the configuration mentioned is
> > > > 'remote.log.storage.system.enable'. However, under "Public Interfaces"
> > > > section the corresponding configuration is
> > 'remote.storage.system.enable'.
> > > > Could we use the same one in both, maybe
> > > > 'remote.log.storage.system.enable'?
> > > >
> > > > 9003. Under "Per Topic Configuration", the KIP recommends setting
> > > > 'remote.log.storage.enable' to true at a per-topic level. It will be
> > useful
> > > > to add a line that if the user wants to enable it for all topics, then
> > they
> > > > should be able to set the cluster-wide default to true. Also, it will
> > be
> > > > useful to mention that the KIP currently does not support setting it to
> > > > false (after it is set to true), and add that to the future work
> > section.
> > > >
> > > > 9004. Under "Committed offsets file format", the sample provided shows
> > > > partition number and offset. Is the topic name required for identifying
> > > > which topic the partitions belong to?
> > > >
> > > > 9005. Under "Internal flat-file store format of remote log metadata",
> > it
> > > > seems useful to specify both topic name and topic ID for debugging
> > > > purposes.
> > > >
> > > > 9006. Under "Internal flat-file store format of remote log metadata",
> > the
> > > > description of "metadata-topic-offset" currently says "offset of the
> > remote
> > > > log metadata topic from which this topic partition's remote log
> > metadata is
> > > > fetched." Just for the wording, perhaps you meant to refer to the
> > offset
> > > > upto which the file has been committed? i.e. "offset of the remote log
> > > > metadata topic upto which this topic partition's remote log metadata
> > has
> > > > been committed into this file."
> > > >
> > > > 9007. Under "Internal flat-file store format of remote log metadata",
> > the
> > > > schema of the payload (i.e. beyond the header) seems to contain the
> > events
> > > > from the metadata topic. It seems useful to instead persist the
> > > > representation of the materialized state of the events, so that for the
> > > > same segment only the latest state is stored. Besides reducing storage
> > > > footprint, this also is likely to relate directly with the in-memory
> > > > representation of the RLMM cache (which probably is some kind of a Map
> > with
> > > > key being segment ID and value being the segment state), so recovery
> > from
> > > > disk will be straightforward.
> > > >
> > > > 9008. Under "Topic deletion lifecycle", step (1), it will be useful to
> > > > mention when in the deletion flow does the controller publish the
> > > > delete_partition_marked event to say that the partition is marked for
> > > > deletion?
> > > >
> > > > 9009. There are ~4 TODOs in the KIP. Could you please address these or
> > > > remove them?
> > > >
> > > > 9010. There is a reference to a Google doc on the KIP which was used
> > > > earlier for discussions. Please could you remove the reference, since
> > the
> > > > KIP is the source of the truth?
> > > >
> > > > 9011. This feedback is from an earlier comment. In the
> > RemoteStorageManager
> > > > interface, there is an API defined for each file type. For example,
> > > > fetchOffsetIndex, fetchTimestampIndex etc. To avoid the duplication,
> > I'd
> > > > suggest we can instead have a FileType enum and a common get API based
> > on
> > > > the FileType. What do you think?
> > > >
> > > >
> > > > Cheers,
> > > > Kowshik
> > > >
> > > >
> > > > On Mon, Dec 14, 2020 at 11:07 AM Satish Duggana <
> > satish.duggana@gmail.com>
> > > > wrote:
> > > >
> > > > > Hi Jun,
> > > > > Thanks for your comments. Please go through the inline replies.
> > > > >
> > > > >
> > > > > 5102.2: It seems that both positions can just be int. Another option
> > is
> > > > to
> > > > > have two methods. Would it be clearer?
> > > > >
> > > > >     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> > > > > remoteLogSegmentMetadata,  int startPosition)
> > > > throwsRemoteStorageException;
> > > > >
> > > > >     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> > > > > remoteLogSegmentMetadata, int startPosition, int endPosition) throws
> > > > > RemoteStorageException;
> > > > >
> > > > > That makes sense to me, updated the KIP.
> > > > >
> > > > > 6003: Could you also update the javadoc for the return value?
> > > > >
> > > > > Updated.
> > > > >
> > > > > 6020: local.log.retention.bytes: Should it default to
> > log.retention.bytes
> > > > > to be consistent with local.log.retention.ms?
> > > > >
> > > > > Yes, it can be defaulted to log.retention.bytes.
> > > > >
> > > > > 6021: Could you define TopicIdPartition?
> > > > >
> > > > > Added TopicIdPartition in the KIP.
> > > > >
> > > > > 6022: For all public facing classes, could you specify the package
> > name?
> > > > >
> > > > > Updated.
> > > > >
> > > > >
> > > > > Thanks,
> > > > > Satish.
> > > > >
> > > > > On Tue, Dec 8, 2020 at 12:59 AM Jun Rao <ju...@confluent.io> wrote:
> > > > > >
> > > > > > Hi, Satish,
> > > > > >
> > > > > > Thanks for the reply. A few more comments below.
> > > > > >
> > > > > > 5102.2: It seems that both positions can just be int. Another
> > option is
> > > > > to
> > > > > > have two methods. Would it be clearer?
> > > > > >
> > > > > >     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> > > > > > remoteLogSegmentMetadata,
> > > > > >                                     int startPosition) throws
> > > > > > RemoteStorageException;
> > > > > >
> > > > > >     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> > > > > > remoteLogSegmentMetadata,
> > > > > >                                     int startPosition, int
> > endPosition)
> > > > > > throws RemoteStorageException;
> > > > > >
> > > > > > 6003: Could you also update the javadoc for the return value?
> > > > > >
> > > > > > 6010: What kind of tiering throughput have you seen with 5 threads?
> > > > > >
> > > > > > 6020: local.log.retention.bytes: Should it default to
> > > > log.retention.bytes
> > > > > > to be consistent with local.log.retention.ms?
> > > > > >
> > > > > > 6021: Could you define TopicIdPartition?
> > > > > >
> > > > > > 6022: For all public facing classes, could you specify the package
> > > > name?
> > > > > >
> > > > > > It seems that you already added the topicId support. Two other
> > > > remaining
> > > > > > items are (a) the format of local tier metadata storage and (b)
> > > > upgrade.
> > > > > >
> > > > > > Jun
> > > > > >
> > > > > > On Mon, Dec 7, 2020 at 8:56 AM Satish Duggana <
> > > > satish.duggana@gmail.com>
> > > > > > wrote:
> > > > > >
> > > > > > > Hi Jun,
> > > > > > > Thanks for your comments. Please find the inline replies below.
> > > > > > >
> > > > > > > >605.2 It's rare for the follower to need the remote data. So,
> > the
> > > > > current
> > > > > > > approach is fine too. Could you document the process of
> > rebuilding
> > > > the
> > > > > > > producer state since we can't simply trim the producerState to an
> > > > > offset in
> > > > > > > the middle of a segment.
> > > > > > >
> > > > > > > Will clarify in the KIP.
> > > > > > >
> > > > > > > >5102.2 Would it be clearer to make startPosiont long and
> > endPosition
> > > > > of
> > > > > > > Optional<Long>?
> > > > > > >
> > > > > > > We will have arg checks with respective validation. It is not a
> > good
> > > > > > > practice to have arguments with optional as mentioned here.
> > > > > > > https://rules.sonarsource.com/java/RSPEC-3553
> > > > > > >
> > > > > > >
> > > > > > > >5102.5 LogSegmentData still has leaderEpochIndex as File
> > instead of
> > > > > > > ByteBuffer.
> > > > > > >
> > > > > > > Updated.
> > > > > > >
> > > > > > > >5102.7 Could you define all public methods for LogSegmentData?
> > > > > > >
> > > > > > > Updated.
> > > > > > >
> > > > > > > >5103.5 Could you change the reference to
> > rlm_process_interval_ms and
> > > > > > > rlm_retry_interval_ms to the new config names? Also, the retry
> > > > interval
> > > > > > > config seems still missing. It would be useful to support
> > exponential
> > > > > > > backoff with the retry interval config.
> > > > > > >
> > > > > > > Good point. We wanted the retry with truncated exponential
> > backoff,
> > > > > > > updated the KIP.
> > > > > > >
> > > > > > > >5111. "RLM follower fetches the earliest offset for the earliest
> > > > > leader
> > > > > > > epoch by calling RLMM.earliestLogOffset(TopicPartition
> > > > topicPartition,
> > > > > int
> > > > > > > leaderEpoch) and updates that as the log start offset." This
> > text is
> > > > > still
> > > > > > > there. Also, could we remove earliestLogOffset() from RLMM?
> > > > > > >
> > > > > > > Updated.
> > > > > > >
> > > > > > > >5115. There are still references to "remote log cleaners".
> > > > > > >
> > > > > > > Updated.
> > > > > > >
> > > > > > > >6000. Since we are returning new error codes, we need to bump
> > up the
> > > > > > > protocol version for Fetch request. Also, it will be useful to
> > > > > document all
> > > > > > > new error codes and whether they are retriable or not.
> > > > > > >
> > > > > > > Sure, we will add that in the KIP.
> > > > > > >
> > > > > > > >6001. public Map<Long, Long> segmentLeaderEpochs(): Currently,
> > > > > leaderEpoch
> > > > > > > is int32 instead of long.
> > > > > > >
> > > > > > > Updated.
> > > > > > >
> > > > > > > >6002. Is RemoteLogSegmentMetadata.markedForDeletion() needed
> > given
> > > > > > > RemoteLogSegmentMetadata.state()?
> > > > > > >
> > > > > > > No, it is fixed.
> > > > > > >
> > > > > > > >6003. RemoteLogSegmentMetadata
> > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > topicPartition, long offset, int epochForOffset): Should this
> > return
> > > > > > > Optional<RemoteLogSegmentMetadata>?
> > > > > > >
> > > > > > > That makes sense, updated.
> > > > > > >
> > > > > > > >6005. RemoteLogState: It seems it's better to split it between
> > > > > > > DeletePartitionUpdate and RemoteLogSegmentMetadataUpdate since
> > the
> > > > > states
> > > > > > > are never shared between the two use cases.
> > > > > > >
> > > > > > > Agree with that, updated.
> > > > > > >
> > > > > > > >6006. RLMM.onPartitionLeadershipChanges(): This may be ok.
> > However,
> > > > > is it
> > > > > > > ture that other than the metadata topic, RLMM just needs to know
> > > > > whether
> > > > > > > there is a replica assigned to this broker and doesn't need to
> > know
> > > > > whether
> > > > > > > the replica is the leader or the follower?
> > > > > > >
> > > > > > > That may be true. If the implementation does not need that, it
> > can
> > > > > > > ignore the information in the callback.
> > > > > > >
> > > > > > > >6007: "Handle expired remote segments (leader and follower)":
> > Why is
> > > > > this
> > > > > > > needed in both the leader and the follower?
> > > > > > >
> > > > > > > Updated.
> > > > > > >
> > > > > > > >6008.       "name": "SegmentSizeInBytes",
> > > > > > >                 "type": "int64",
> > > > > > > The segment size can just be int32.
> > > > > > >
> > > > > > > Updated.
> > > > > > >
> > > > > > > >6009. For the record format in the log, it seems that we need
> > to add
> > > > > > > record
> > > > > > > type and record version before the serialized bytes. We can
> > follow
> > > > the
> > > > > > > convention used in
> > > > > > >
> > > > > > >
> > > > >
> > > >
> > https://cwiki.apache.org/confluence/display/KAFKA/KIP-631%3A+The+Quorum-based+Kafka+Controller#KIP631:TheQuorumbasedKafkaController-RecordFormats
> > > > > > >
> > > > > > > Yes, KIP already mentions that these are serialized before the
> > > > payload
> > > > > > > as below. We will mention explicitly that these two are written
> > > > before
> > > > > > > the data is written.
> > > > > > >
> > > > > > > RLMM instance on broker publishes the message to the topic with
> > key
> > > > as
> > > > > > > null and value with the below format.
> > > > > > >
> > > > > > > type      : unsigned var int, represents the value type. This
> > value
> > > > is
> > > > > > > 'apikey' as mentioned in the schema.
> > > > > > > version : unsigned var int, the 'version' number of the type as
> > > > > > > mentioned in the schema.
> > > > > > > data      : record payload in kafka protocol message format.
> > > > > > >
> > > > > > >
> > > > > > > >6010. remote.log.manager.thread.pool.size: The default value is
> > 10.
> > > > > This
> > > > > > > might be too high when enabling the tiered feature for the first
> > > > time.
> > > > > > > Since there are lots of segments that need to be tiered
> > initially, a
> > > > > large
> > > > > > > number of threads could overwhelm the broker.
> > > > > > >
> > > > > > > Is the default value 5 reasonable?
> > > > > > >
> > > > > > > 6011. "The number of milli seconds to keep the local log segment
> > > > > before it
> > > > > > > gets deleted. If not set, the value in `log.retention.minutes` is
> > > > > used. If
> > > > > > > set to -1, no time limit is applied." We should use
> > log.retention.ms
> > > > > > > instead of log.retention.minutes.
> > > > > > > Nice typo catch. Updated the KIP.
> > > > > > >
> > > > > > > Thanks,
> > > > > > > Satish.
> > > > > > >
> > > > > > > On Thu, Dec 3, 2020 at 8:03 AM Jun Rao <ju...@confluent.io> wrote:
> > > > > > > >
> > > > > > > > Hi, Satish,
> > > > > > > >
> > > > > > > > Thanks for the updated KIP. A few more comments below.
> > > > > > > >
> > > > > > > > 605.2 It's rare for the follower to need the remote data. So,
> > the
> > > > > current
> > > > > > > > approach is fine too. Could you document the process of
> > rebuilding
> > > > > the
> > > > > > > > producer state since we can't simply trim the producerState to
> > an
> > > > > offset
> > > > > > > in
> > > > > > > > the middle of a segment.
> > > > > > > >
> > > > > > > > 5102.2 Would it be clearer to make startPosiont long and
> > > > endPosition
> > > > > of
> > > > > > > > Optional<Long>?
> > > > > > > >
> > > > > > > > 5102.5 LogSegmentData still has leaderEpochIndex as File
> > instead of
> > > > > > > > ByteBuffer.
> > > > > > > >
> > > > > > > > 5102.7 Could you define all public methods for LogSegmentData?
> > > > > > > >
> > > > > > > > 5103.5 Could you change the reference to
> > rlm_process_interval_ms
> > > > and
> > > > > > > > rlm_retry_interval_ms to the new config names? Also, the retry
> > > > > interval
> > > > > > > > config seems still missing. It would be useful to support
> > > > exponential
> > > > > > > > backoff with the retry interval config.
> > > > > > > >
> > > > > > > > 5111. "RLM follower fetches the earliest offset for the
> > earliest
> > > > > leader
> > > > > > > > epoch by calling RLMM.earliestLogOffset(TopicPartition
> > > > > topicPartition,
> > > > > > > int
> > > > > > > > leaderEpoch) and updates that as the log start offset." This
> > text
> > > > is
> > > > > > > still
> > > > > > > > there. Also, could we remove earliestLogOffset() from RLMM?
> > > > > > > >
> > > > > > > > 5115. There are still references to "remote log cleaners".
> > > > > > > >
> > > > > > > > 6000. Since we are returning new error codes, we need to bump
> > up
> > > > the
> > > > > > > > protocol version for Fetch request. Also, it will be useful to
> > > > > document
> > > > > > > all
> > > > > > > > new error codes and whether they are retriable or not.
> > > > > > > >
> > > > > > > > 6001. public Map<Long, Long> segmentLeaderEpochs(): Currently,
> > > > > > > leaderEpoch
> > > > > > > > is int32 instead of long.
> > > > > > > >
> > > > > > > > 6002. Is RemoteLogSegmentMetadata.markedForDeletion() needed
> > given
> > > > > > > > RemoteLogSegmentMetadata.state()?
> > > > > > > >
> > > > > > > > 6003. RemoteLogSegmentMetadata
> > > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > topicPartition, long offset, int epochForOffset): Should this
> > > > return
> > > > > > > > Optional<RemoteLogSegmentMetadata>?
> > > > > > > >
> > > > > > > > 6004. DeletePartitionUpdate.epoch(): It would be useful to
> > pick a
> > > > > more
> > > > > > > > indicative name so that people understand what epoch this is.
> > > > > > > >
> > > > > > > > 6005. RemoteLogState: It seems it's better to split it between
> > > > > > > > DeletePartitionUpdate and RemoteLogSegmentMetadataUpdate since
> > the
> > > > > states
> > > > > > > > are never shared between the two use cases.
> > > > > > > >
> > > > > > > > 6006. RLMM.onPartitionLeadershipChanges(): This may be ok.
> > However,
> > > > > is it
> > > > > > > > ture that other than the metadata topic, RLMM just needs to
> > know
> > > > > whether
> > > > > > > > there is a replica assigned to this broker and doesn't need to
> > know
> > > > > > > whether
> > > > > > > > the replica is the leader or the follower?
> > > > > > > >
> > > > > > > > 6007: "Handle expired remote segments (leader and follower)":
> > Why
> > > > is
> > > > > this
> > > > > > > > needed in both the leader and the follower?
> > > > > > > >
> > > > > > > > 6008.       "name": "SegmentSizeInBytes",
> > > > > > > >                 "type": "int64",
> > > > > > > > The segment size can just be int32.
> > > > > > > >
> > > > > > > > 6009. For the record format in the log, it seems that we need
> > to
> > > > add
> > > > > > > record
> > > > > > > > type and record version before the serialized bytes. We can
> > follow
> > > > > the
> > > > > > > > convention used in
> > > > > > > >
> > > > > > >
> > > > >
> > > >
> > https://cwiki.apache.org/confluence/display/KAFKA/KIP-631%3A+The+Quorum-based+Kafka+Controller#KIP631:TheQuorumbasedKafkaController-RecordFormats
> > > > > > > > .
> > > > > > > >
> > > > > > > > 6010. remote.log.manager.thread.pool.size: The default value
> > is 10.
> > > > > This
> > > > > > > > might be too high when enabling the tiered feature for the
> > first
> > > > > time.
> > > > > > > > Since there are lots of segments that need to be tiered
> > initially,
> > > > a
> > > > > > > large
> > > > > > > > number of threads could overwhelm the broker.
> > > > > > > >
> > > > > > > > 6011. "The number of milli seconds to keep the local log
> > segment
> > > > > before
> > > > > > > it
> > > > > > > > gets deleted. If not set, the value in `log.retention.minutes`
> > is
> > > > > used.
> > > > > > > If
> > > > > > > > set to -1, no time limit is applied." We should use
> > > > log.retention.ms
> > > > > > > > instead of log.retention.minutes.
> > > > > > > >
> > > > > > > > Jun
> > > > > > > >
> > > > > > > > On Tue, Dec 1, 2020 at 2:42 AM Satish Duggana <
> > > > > satish.duggana@gmail.com>
> > > > > > > > wrote:
> > > > > > > >
> > > > > > > > > Hi,
> > > > > > > > > We updated the KIP with the points mentioned in the earlier
> > mail
> > > > > > > > > except for KIP-516 related changes. You can go through them
> > and
> > > > > let us
> > > > > > > > > know if you have any comments. We will update the KIP with
> > the
> > > > > > > > > remaining todo items and KIP-516 related changes by end of
> > this
> > > > > > > > > week(5th Dec).
> > > > > > > > >
> > > > > > > > > Thanks,
> > > > > > > > > Satish.
> > > > > > > > >
> > > > > > > > > On Tue, Nov 10, 2020 at 8:26 PM Satish Duggana <
> > > > > > > satish.duggana@gmail.com>
> > > > > > > > > wrote:
> > > > > > > > > >
> > > > > > > > > > Hi Jun,
> > > > > > > > > > Thanks for your comments. Please find the inline replies
> > below.
> > > > > > > > > >
> > > > > > > > > > 605.2 "Build the local leader epoch cache by cutting the
> > leader
> > > > > epoch
> > > > > > > > > > sequence received from remote storage to [LSO, ELO]." I
> > > > > mentioned an
> > > > > > > > > issue
> > > > > > > > > > earlier. Suppose the leader's local start offset is 100.
> > The
> > > > > follower
> > > > > > > > > finds
> > > > > > > > > > a remote segment covering offset range [80, 120). The
> > > > > producerState
> > > > > > > with
> > > > > > > > > > this remote segment is up to offset 120. To trim the
> > > > > producerState to
> > > > > > > > > > offset 100 requires more work since one needs to download
> > the
> > > > > > > previous
> > > > > > > > > > producerState up to offset 80 and then replay the messages
> > from
> > > > > 80 to
> > > > > > > > > 100.
> > > > > > > > > > It seems that it's simpler in this case for the follower
> > just
> > > > to
> > > > > > > take the
> > > > > > > > > > remote segment as it is and start fetching from offset 120.
> > > > > > > > > >
> > > > > > > > > > We chose that approach to avoid any edge cases here. It
> > may be
> > > > > > > > > > possible that the remote log segment that is received may
> > not
> > > > > have
> > > > > > > the
> > > > > > > > > > same leader epoch sequence from 100-120 as it contains on
> > the
> > > > > > > > > > leader(this can happen due to unclean leader). It is safe
> > to
> > > > > start
> > > > > > > > > > from what the leader returns here.Another way is to find
> > the
> > > > > remote
> > > > > > > > > > log segment
> > > > > > > > > >
> > > > > > > > > > 5016. Just to echo what Kowshik was saying. It seems that
> > > > > > > > > > RLMM.onPartitionLeadershipChanges() is only called on the
> > > > > replicas
> > > > > > > for a
> > > > > > > > > > partition, not on the replicas for the
> > > > > __remote_log_segment_metadata
> > > > > > > > > > partition. It's not clear how the leader of
> > > > > > > __remote_log_segment_metadata
> > > > > > > > > > obtains the metadata for remote segments for deletion.
> > > > > > > > > >
> > > > > > > > > > RLMM will always receive the callback for the remote log
> > > > metadata
> > > > > > > > > > topic partitions hosted on the local broker and these will
> > be
> > > > > > > > > > subscribed. I will make this clear in the KIP.
> > > > > > > > > >
> > > > > > > > > > 5100. KIP-516 has been accepted and is being implemented
> > now.
> > > > > Could
> > > > > > > you
> > > > > > > > > > update the KIP based on topicID?
> > > > > > > > > >
> > > > > > > > > > We mentioned KIP-516 and how it helps. We will update this
> > KIP
> > > > > with
> > > > > > > > > > all the changes it brings with KIP-516.
> > > > > > > > > >
> > > > > > > > > > 5101. RLMM: It would be useful to clarify how the
> > following two
> > > > > APIs
> > > > > > > are
> > > > > > > > > > used. According to the wiki, the former is used for topic
> > > > > deletion
> > > > > > > and
> > > > > > > > > the
> > > > > > > > > > latter is used for retention. It seems that retention
> > should
> > > > use
> > > > > the
> > > > > > > > > former
> > > > > > > > > > since remote segments without a matching epoch in the
> > leader
> > > > > > > (potentially
> > > > > > > > > > due to unclean leader election) also need to be garbage
> > > > > collected.
> > > > > > > The
> > > > > > > > > > latter seems to be used for the new leader to determine the
> > > > last
> > > > > > > tiered
> > > > > > > > > > segment.
> > > > > > > > > >     default Iterator<RemoteLogSegmentMetadata>
> > > > > > > > > > listRemoteLogSegments(TopicPartition topicPartition)
> > > > > > > > > >     Iterator<RemoteLogSegmentMetadata>
> > > > > > > > > listRemoteLogSegments(TopicPartition
> > > > > > > > > > topicPartition, long leaderEpoch);
> > > > > > > > > >
> > > > > > > > > > Right,.that is what we are currently doing. We will update
> > the
> > > > > > > > > > javadocs and wiki with that. Earlier, we did not want to
> > remove
> > > > > the
> > > > > > > > > > segments which are not matched with leader epochs from the
> > > > ladder
> > > > > > > > > > partition as they may be used later by a replica which can
> > > > > become a
> > > > > > > > > > leader (unclean leader election) and refer those segments.
> > But
> > > > > that
> > > > > > > > > > may leak these segments in remote storage until the topic
> > > > > lifetime.
> > > > > > > We
> > > > > > > > > > decided to cleanup the segments with the oldest incase of
> > size
> > > > > based
> > > > > > > > > > retention also.
> > > > > > > > > >
> > > > > > > > > > 5102. RSM:
> > > > > > > > > > 5102.1 For methods like fetchLogSegmentData(), it seems
> > that
> > > > > they can
> > > > > > > > > > use RemoteLogSegmentId instead of RemoteLogSegmentMetadata.
> > > > > > > > > >
> > > > > > > > > > It will be useful to have metadata for RSM to fetch log
> > > > segment.
> > > > > It
> > > > > > > > > > may create location/path using id with other metadata too.
> > > > > > > > > >
> > > > > > > > > > 5102.2 In fetchLogSegmentData(), should we use long
> > instead of
> > > > > Long?
> > > > > > > > > >
> > > > > > > > > > Wanted to keep endPosition as optional to read till the
> > end of
> > > > > the
> > > > > > > > > > segment and avoid sentinels.
> > > > > > > > > >
> > > > > > > > > > 5102.3 Why only some of the methods have default
> > implementation
> > > > > and
> > > > > > > > > others
> > > > > > > > > > Don't?
> > > > > > > > > >
> > > > > > > > > > Actually,  RSM will not have any default implementations.
> > > > Those 3
> > > > > > > > > > methods were made default earlier for tests etc. Updated
> > the
> > > > > wiki.
> > > > > > > > > >
> > > > > > > > > > 5102.4. Could we define RemoteLogSegmentMetadataUpdate
> > > > > > > > > > and DeletePartitionUpdate?
> > > > > > > > > >
> > > > > > > > > > Sure, they will be added.
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > 5102.5 LogSegmentData: It seems that it's easier to pass
> > > > > > > > > > in leaderEpochIndex as a ByteBuffer or byte array than a
> > file
> > > > > since
> > > > > > > it
> > > > > > > > > will
> > > > > > > > > > be generated in memory.
> > > > > > > > > >
> > > > > > > > > > Right, this is in plan.
> > > > > > > > > >
> > > > > > > > > > 5102.6 RemoteLogSegmentMetadata: It seems that it needs
> > both
> > > > > > > baseOffset
> > > > > > > > > and
> > > > > > > > > > startOffset. For example, deleteRecords() could move the
> > > > > startOffset
> > > > > > > to
> > > > > > > > > the
> > > > > > > > > > middle of a segment. If we copy the full segment to remote
> > > > > storage,
> > > > > > > the
> > > > > > > > > > baseOffset and the startOffset will be different.
> > > > > > > > > >
> > > > > > > > > > Good point. startOffset is baseOffset by default, if not
> > set
> > > > > > > explicitly.
> > > > > > > > > >
> > > > > > > > > > 5102.7 Could we define all the public methods for
> > > > > > > > > RemoteLogSegmentMetadata
> > > > > > > > > > and LogSegmentData?
> > > > > > > > > >
> > > > > > > > > > Sure, updated the wiki.
> > > > > > > > > >
> > > > > > > > > > 5102.8 Could we document whether endOffset in
> > > > > > > RemoteLogSegmentMetadata is
> > > > > > > > > > inclusive/exclusive?
> > > > > > > > > >
> > > > > > > > > > It is inclusive, will update.
> > > > > > > > > >
> > > > > > > > > > 5103. configs:
> > > > > > > > > > 5103.1 Could we define the default value of non-required
> > > > configs
> > > > > > > (e.g the
> > > > > > > > > > size of new thread pools)?
> > > > > > > > > >
> > > > > > > > > > Sure, that makes sense.
> > > > > > > > > >
> > > > > > > > > > 5103.2 It seems that local.log.retention.ms should
> > default to
> > > > > > > > > retention.ms,
> > > > > > > > > > instead of remote.log.retention.minutes. Similarly, it
> > seems
> > > > > > > > > > that local.log.retention.bytes should default to
> > segment.bytes.
> > > > > > > > > >
> > > > > > > > > > Right, we do not have  remote.log.retention as we discussed
> > > > > earlier.
> > > > > > > > > > Thanks for catching the typo.
> > > > > > > > > >
> > > > > > > > > > 5103.3 remote.log.manager.thread.pool.size: The description
> > > > says
> > > > > > > "used in
> > > > > > > > > > scheduling tasks to copy segments, fetch remote log
> > indexes and
> > > > > > > clean up
> > > > > > > > > > remote log segments". However, there is a separate
> > > > > > > > > > config remote.log.reader.threads for fetching remote data.
> > It's
> > > > > > > weird to
> > > > > > > > > > fetch remote index and log in different thread pools since
> > both
> > > > > are
> > > > > > > used
> > > > > > > > > > for serving fetch requests.
> > > > > > > > > >
> > > > > > > > > > Right, remote.log.manager.thread.pool is mainly used for
> > > > > copy/cleanup
> > > > > > > > > > activities. Fetch path always goes through
> > > > > remote.log.reader.threads.
> > > > > > > > > >
> > > > > > > > > > 5103.4 remote.log.manager.task.interval.ms: Is that the
> > amount
> > > > > of
> > > > > > > time
> > > > > > > > > to
> > > > > > > > > > back off when there is no work to do? If so, perhaps it
> > can be
> > > > > > > renamed as
> > > > > > > > > > backoff.ms.
> > > > > > > > > >
> > > > > > > > > > This is the delay interval for each iteration. It may be
> > > > renamed
> > > > > to
> > > > > > > > > > remote.log.manager.task.delay.ms
> > > > > > > > > >
> > > > > > > > > > 5103.5 Are rlm_process_interval_ms and
> > rlm_retry_interval_ms
> > > > > > > configs? If
> > > > > > > > > > so, they need to be listed in this section.
> > > > > > > > > >
> > > > > > > > > > remote.log.manager.task.interval.ms is the process
> > internal,
> > > > > retry
> > > > > > > > > > interval is missing in the configs, which will be updated
> > in
> > > > the
> > > > > KIP.
> > > > > > > > > >
> > > > > > > > > > 5104. "RLM maintains a bounded cache(possibly LRU) of the
> > index
> > > > > > > files of
> > > > > > > > > > remote log segments to avoid multiple index fetches from
> > the
> > > > > remote
> > > > > > > > > > storage." Is the RLM in memory or on disk? If on disk,
> > where is
> > > > > it
> > > > > > > > > stored?
> > > > > > > > > > Do we need a configuration to bound the size?
> > > > > > > > > >
> > > > > > > > > > It is stored on disk. They are stored in a directory
> > > > > > > > > > `remote-log-index-cache` under log dir. We plan to have a
> > > > config
> > > > > for
> > > > > > > > > > that instead of default. We will have a configuration for
> > that.
> > > > > > > > > >
> > > > > > > > > > 5105. The KIP uses local-log-start-offset and Earliest
> > Local
> > > > > Offset
> > > > > > > in
> > > > > > > > > > different places. It would be useful to standardize the
> > > > > terminology.
> > > > > > > > > >
> > > > > > > > > > Sure.
> > > > > > > > > >
> > > > > > > > > > 5106. The section on "In BuildingRemoteLogAux state". It
> > listed
> > > > > two
> > > > > > > > > options
> > > > > > > > > > without saying which option is chosen.
> > > > > > > > > > We already mentioned in the KIP that we chose option-2.
> > > > > > > > > >
> > > > > > > > > > 5107. Follower to leader transition: It has step 2, but not
> > > > step
> > > > > 1.
> > > > > > > > > > Step-1 is there but it is not explicitly highlighted. It is
> > > > > previous
> > > > > > > > > > table to step-2.
> > > > > > > > > >
> > > > > > > > > > 5108. If a consumer fetches from the remote data and the
> > remote
> > > > > > > storage
> > > > > > > > > is
> > > > > > > > > > not available, what error code is used in the fetch
> > response?
> > > > > > > > > >
> > > > > > > > > > Good point. We have not yet defined the error for this
> > case. We
> > > > > need
> > > > > > > > > > to define an error message and send the same in fetch
> > response.
> > > > > > > > > >
> > > > > > > > > > 5109. "ListOffsets: For timestamps >= 0, it returns the
> > first
> > > > > message
> > > > > > > > > > offset whose timestamp is >= to the given timestamp in the
> > > > > request.
> > > > > > > That
> > > > > > > > > > means it checks in remote log time indexes first, after
> > which
> > > > > local
> > > > > > > log
> > > > > > > > > > time indexes are checked." Could you document which method
> > in
> > > > > RLMM is
> > > > > > > > > used
> > > > > > > > > > for this?
> > > > > > > > > >
> > > > > > > > > > Okay.
> > > > > > > > > >
> > > > > > > > > > 5110. Stopreplica: "it sets all the remote log segment
> > metadata
> > > > > of
> > > > > > > that
> > > > > > > > > > partition with a delete marker and publishes them to RLMM."
> > > > This
> > > > > > > seems
> > > > > > > > > > outdated given the new topic deletion logic.
> > > > > > > > > >
> > > > > > > > > > Will update with KIP-516 related points.
> > > > > > > > > >
> > > > > > > > > > 5111. "RLM follower fetches the earliest offset for the
> > > > earliest
> > > > > > > leader
> > > > > > > > > > epoch by calling RLMM.earliestLogOffset(TopicPartition
> > > > > > > topicPartition,
> > > > > > > > > int
> > > > > > > > > > leaderEpoch) and updates that as the log start offset." Do
> > we
> > > > > need
> > > > > > > that
> > > > > > > > > > since replication propagates logStartOffset already?
> > > > > > > > > >
> > > > > > > > > > Good point. Right, existing replication protocol takes
> > care of
> > > > > > > > > > updating the followers’s log start offset received from the
> > > > > leader.
> > > > > > > > > >
> > > > > > > > > > 5112. Is the default maxWaitMs of 500ms enough for fetching
> > > > from
> > > > > > > remote
> > > > > > > > > > storage?
> > > > > > > > > >
> > > > > > > > > > Remote reads may fail within the current default wait
> > time, but
> > > > > > > > > > subsequent fetches would be able to serve as that data is
> > > > stored
> > > > > in
> > > > > > > > > > the local cache. This cache is currently implemented in
> > RSMs.
> > > > > But we
> > > > > > > > > > plan to pull this into the remote log messaging layer in
> > > > future.
> > > > > > > > > >
> > > > > > > > > > 5113. "Committed offsets can be stored in a local file to
> > avoid
> > > > > > > reading
> > > > > > > > > the
> > > > > > > > > > messages again when a broker is restarted." Could you
> > describe
> > > > > the
> > > > > > > format
> > > > > > > > > > and the location of the file? Also, could the same message
> > be
> > > > > > > processed
> > > > > > > > > by
> > > > > > > > > > RLMM again after broker restart? If so, how do we handle
> > that?
> > > > > > > > > >
> > > > > > > > > > Sure, we will update in the KIP.
> > > > > > > > > >
> > > > > > > > > > 5114. Message format
> > > > > > > > > > 5114.1 There are two records named
> > > > RemoteLogSegmentMetadataRecord
> > > > > > > with
> > > > > > > > > > apiKey 0 and 1.
> > > > > > > > > >
> > > > > > > > > > Nice catch, that was a typo. Fixed in the wiki.
> > > > > > > > > >
> > > > > > > > > > 5114.2 RemoteLogSegmentMetadataRecord: Could we document
> > > > whether
> > > > > > > > > endOffset
> > > > > > > > > > is inclusive/exclusive?
> > > > > > > > > > It is inclusive, will update.
> > > > > > > > > >
> > > > > > > > > > 5114.3 RemoteLogSegmentMetadataRecord: Could you explain
> > > > > LeaderEpoch
> > > > > > > a
> > > > > > > > > bit
> > > > > > > > > > more? Is that the epoch of the leader when it copies the
> > > > segment
> > > > > to
> > > > > > > > > remote
> > > > > > > > > > storage? Also, how will this field be used?
> > > > > > > > > >
> > > > > > > > > > Right, this is the leader epoch of the broker which copied
> > this
> > > > > > > > > > segment. This is helpful in reason about which broker
> > copied
> > > > the
> > > > > > > > > > segment to remote storage.
> > > > > > > > > >
> > > > > > > > > > 5114.4 EventTimestamp: Could you explain this a bit more?
> > Each
> > > > > > > record in
> > > > > > > > > > Kafka already has a timestamp field. Could we just use
> > that?
> > > > > > > > > >
> > > > > > > > > > This is the  timestamp at which  the respective event
> > occurred.
> > > > > Added
> > > > > > > > > > this  to RemoteLogSegmentMetadata as RLMM can be  any other
> > > > > > > > > > implementation. We thought about that but it looked
> > cleaner to
> > > > > use at
> > > > > > > > > > the message structure level instead of getting that from
> > the
> > > > > consumer
> > > > > > > > > > record and using that to build the respective event.
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > 5114.5 SegmentSizeInBytes: Could this just be int32?
> > > > > > > > > >
> > > > > > > > > > Right, it looks like config allows only int value >= 14.
> > > > > > > > > >
> > > > > > > > > > 5115. RemoteLogCleaner(RLC): This could be confused with
> > the
> > > > log
> > > > > > > cleaner
> > > > > > > > > > for compaction. Perhaps it can be renamed to sth like
> > > > > > > > > > RemotePartitionRemover.
> > > > > > > > > >
> > > > > > > > > > I am fine with RemotePartitionRemover or
> > > > > RemoteLogDeletionManager(we
> > > > > > > > > > have other manager classes like RLM, RLMM).
> > > > > > > > > >
> > > > > > > > > > 5116. "RLC receives the delete_partition_marked and
> > processes
> > > > it
> > > > > if
> > > > > > > it is
> > > > > > > > > > not yet processed earlier." How does it know whether
> > > > > > > > > > delete_partition_marked has been processed earlier?
> > > > > > > > > >
> > > > > > > > > > This is to handle duplicate delete_partition_marked
> > events. RLC
> > > > > > > > > > internally maintains a state for the delete_partition
> > events
> > > > and
> > > > > if
> > > > > > > it
> > > > > > > > > > already has an existing event then it ignores if it is
> > already
> > > > > being
> > > > > > > > > > processed.
> > > > > > > > > >
> > > > > > > > > > 5117. Should we add a new MessageFormatter to read the tier
> > > > > metadata
> > > > > > > > > topic?
> > > > > > > > > >
> > > > > > > > > > Right, this is in plan but did not mention it in the KIP.
> > This
> > > > > will
> > > > > > > be
> > > > > > > > > > useful for debugging purposes too.
> > > > > > > > > >
> > > > > > > > > > 5118. "Maximum remote log reader thread pool task queue
> > size.
> > > > If
> > > > > the
> > > > > > > task
> > > > > > > > > > queue is full, broker will stop reading remote log
> > segments."
> > > > > What
> > > > > > > do we
> > > > > > > > > > return to the fetch request in this case?
> > > > > > > > > >
> > > > > > > > > > We return an error response for that partition.
> > > > > > > > > >
> > > > > > > > > > 5119. It would be useful to list all things not supported
> > in
> > > > the
> > > > > > > first
> > > > > > > > > > version in a Future work or Limitations section. For
> > example,
> > > > > > > compacted
> > > > > > > > > > topic, JBOD, changing remote.log.storage.enable from true
> > to
> > > > > false,
> > > > > > > etc.
> > > > > > > > > >
> > > > > > > > > > We already have a non-goals section which is filled with
> > some
> > > > of
> > > > > > > these
> > > > > > > > > > details. Do we need another limitations section?
> > > > > > > > > >
> > > > > > > > > > Thanks,
> > > > > > > > > > Satish.
> > > > > > > > > >
> > > > > > > > > > On Wed, Nov 4, 2020 at 11:27 PM Jun Rao <ju...@confluent.io>
> > > > > wrote:
> > > > > > > > > > >
> > > > > > > > > > > Hi, Satish,
> > > > > > > > > > >
> > > > > > > > > > > Thanks for the updated KIP. A few more comments below.
> > > > > > > > > > >
> > > > > > > > > > > 605.2 "Build the local leader epoch cache by cutting the
> > > > leader
> > > > > > > epoch
> > > > > > > > > > > sequence received from remote storage to [LSO, ELO]." I
> > > > > mentioned
> > > > > > > an
> > > > > > > > > issue
> > > > > > > > > > > earlier. Suppose the leader's local start offset is 100.
> > The
> > > > > > > follower
> > > > > > > > > finds
> > > > > > > > > > > a remote segment covering offset range [80, 120). The
> > > > > producerState
> > > > > > > > > with
> > > > > > > > > > > this remote segment is up to offset 120. To trim the
> > > > > producerState
> > > > > > > to
> > > > > > > > > > > offset 100 requires more work since one needs to
> > download the
> > > > > > > previous
> > > > > > > > > > > producerState up to offset 80 and then replay the
> > messages
> > > > > from 80
> > > > > > > to
> > > > > > > > > 100.
> > > > > > > > > > > It seems that it's simpler in this case for the follower
> > just
> > > > > to
> > > > > > > take
> > > > > > > > > the
> > > > > > > > > > > remote segment as it is and start fetching from offset
> > 120.
> > > > > > > > > > >
> > > > > > > > > > > 5016. Just to echo what Kowshik was saying. It seems that
> > > > > > > > > > > RLMM.onPartitionLeadershipChanges() is only called on the
> > > > > replicas
> > > > > > > for
> > > > > > > > > a
> > > > > > > > > > > partition, not on the replicas for the
> > > > > > > __remote_log_segment_metadata
> > > > > > > > > > > partition. It's not clear how the leader of
> > > > > > > > > __remote_log_segment_metadata
> > > > > > > > > > > obtains the metadata for remote segments for deletion.
> > > > > > > > > > >
> > > > > > > > > > > 5100. KIP-516 has been accepted and is being implemented
> > now.
> > > > > > > Could you
> > > > > > > > > > > update the KIP based on topicID?
> > > > > > > > > > >
> > > > > > > > > > > 5101. RLMM: It would be useful to clarify how the
> > following
> > > > two
> > > > > > > APIs
> > > > > > > > > are
> > > > > > > > > > > used. According to the wiki, the former is used for topic
> > > > > deletion
> > > > > > > and
> > > > > > > > > the
> > > > > > > > > > > latter is used for retention. It seems that retention
> > should
> > > > > use
> > > > > > > the
> > > > > > > > > former
> > > > > > > > > > > since remote segments without a matching epoch in the
> > leader
> > > > > > > > > (potentially
> > > > > > > > > > > due to unclean leader election) also need to be garbage
> > > > > collected.
> > > > > > > The
> > > > > > > > > > > latter seems to be used for the new leader to determine
> > the
> > > > > last
> > > > > > > tiered
> > > > > > > > > > > segment.
> > > > > > > > > > >     default Iterator<RemoteLogSegmentMetadata>
> > > > > > > > > > > listRemoteLogSegments(TopicPartition topicPartition)
> > > > > > > > > > >     Iterator<RemoteLogSegmentMetadata>
> > > > > > > > > listRemoteLogSegments(TopicPartition
> > > > > > > > > > > topicPartition, long leaderEpoch);
> > > > > > > > > > >
> > > > > > > > > > > 5102. RSM:
> > > > > > > > > > > 5102.1 For methods like fetchLogSegmentData(), it seems
> > that
> > > > > they
> > > > > > > can
> > > > > > > > > > > use RemoteLogSegmentId instead of
> > RemoteLogSegmentMetadata.
> > > > > > > > > > > 5102.2 In fetchLogSegmentData(), should we use long
> > instead
> > > > of
> > > > > > > Long?
> > > > > > > > > > > 5102.3 Why only some of the methods have default
> > > > > implementation and
> > > > > > > > > others
> > > > > > > > > > > don't?
> > > > > > > > > > > 5102.4. Could we define RemoteLogSegmentMetadataUpdate
> > > > > > > > > > > and DeletePartitionUpdate?
> > > > > > > > > > > 5102.5 LogSegmentData: It seems that it's easier to pass
> > > > > > > > > > > in leaderEpochIndex as a ByteBuffer or byte array than a
> > file
> > > > > > > since it
> > > > > > > > > will
> > > > > > > > > > > be generated in memory.
> > > > > > > > > > > 5102.6 RemoteLogSegmentMetadata: It seems that it needs
> > both
> > > > > > > > > baseOffset and
> > > > > > > > > > > startOffset. For example, deleteRecords() could move the
> > > > > > > startOffset
> > > > > > > > > to the
> > > > > > > > > > > middle of a segment. If we copy the full segment to
> > remote
> > > > > > > storage, the
> > > > > > > > > > > baseOffset and the startOffset will be different.
> > > > > > > > > > > 5102.7 Could we define all the public methods for
> > > > > > > > > RemoteLogSegmentMetadata
> > > > > > > > > > > and LogSegmentData?
> > > > > > > > > > > 5102.8 Could we document whether endOffset in
> > > > > > > RemoteLogSegmentMetadata
> > > > > > > > > is
> > > > > > > > > > > inclusive/exclusive?
> > > > > > > > > > >
> > > > > > > > > > > 5103. configs:
> > > > > > > > > > > 5103.1 Could we define the default value of non-required
> > > > > configs
> > > > > > > (e.g
> > > > > > > > > the
> > > > > > > > > > > size of new thread pools)?
> > > > > > > > > > > 5103.2 It seems that local.log.retention.ms should
> > default
> > > > to
> > > > > > > > > retention.ms,
> > > > > > > > > > > instead of remote.log.retention.minutes. Similarly, it
> > seems
> > > > > > > > > > > that local.log.retention.bytes should default to
> > > > segment.bytes.
> > > > > > > > > > > 5103.3 remote.log.manager.thread.pool.size: The
> > description
> > > > > says
> > > > > > > "used
> > > > > > > > > in
> > > > > > > > > > > scheduling tasks to copy segments, fetch remote log
> > indexes
> > > > and
> > > > > > > clean
> > > > > > > > > up
> > > > > > > > > > > remote log segments". However, there is a separate
> > > > > > > > > > > config remote.log.reader.threads for fetching remote
> > data.
> > > > It's
> > > > > > > weird
> > > > > > > > > to
> > > > > > > > > > > fetch remote index and log in different thread pools
> > since
> > > > > both are
> > > > > > > > > used
> > > > > > > > > > > for serving fetch requests.
> > > > > > > > > > > 5103.4 remote.log.manager.task.interval.ms: Is that the
> > > > > amount of
> > > > > > > > > time to
> > > > > > > > > > > back off when there is no work to do? If so, perhaps it
> > can
> > > > be
> > > > > > > renamed
> > > > > > > > > as
> > > > > > > > > > > backoff.ms.
> > > > > > > > > > > 5103.5 Are rlm_process_interval_ms and
> > rlm_retry_interval_ms
> > > > > > > configs?
> > > > > > > > > If
> > > > > > > > > > > so, they need to be listed in this section.
> > > > > > > > > > >
> > > > > > > > > > > 5104. "RLM maintains a bounded cache(possibly LRU) of the
> > > > index
> > > > > > > files
> > > > > > > > > of
> > > > > > > > > > > remote log segments to avoid multiple index fetches from
> > the
> > > > > remote
> > > > > > > > > > > storage." Is the RLM in memory or on disk? If on disk,
> > where
> > > > > is it
> > > > > > > > > stored?
> > > > > > > > > > > Do we need a configuration to bound the size?
> > > > > > > > > > >
> > > > > > > > > > > 5105. The KIP uses local-log-start-offset and Earliest
> > Local
> > > > > > > Offset in
> > > > > > > > > > > different places. It would be useful to standardize the
> > > > > > > terminology.
> > > > > > > > > > >
> > > > > > > > > > > 5106. The section on "In BuildingRemoteLogAux state". It
> > > > > listed two
> > > > > > > > > options
> > > > > > > > > > > without saying which option is chosen.
> > > > > > > > > > >
> > > > > > > > > > > 5107. Follower to leader transition: It has step 2, but
> > not
> > > > > step 1.
> > > > > > > > > > >
> > > > > > > > > > > 5108. If a consumer fetches from the remote data and the
> > > > remote
> > > > > > > > > storage is
> > > > > > > > > > > not available, what error code is used in the fetch
> > response?
> > > > > > > > > > >
> > > > > > > > > > > 5109. "ListOffsets: For timestamps >= 0, it returns the
> > first
> > > > > > > message
> > > > > > > > > > > offset whose timestamp is >= to the given timestamp in
> > the
> > > > > request.
> > > > > > > > > That
> > > > > > > > > > > means it checks in remote log time indexes first, after
> > which
> > > > > > > local log
> > > > > > > > > > > time indexes are checked." Could you document which
> > method in
> > > > > RLMM
> > > > > > > is
> > > > > > > > > used
> > > > > > > > > > > for this?
> > > > > > > > > > >
> > > > > > > > > > > 5110. Stopreplica: "it sets all the remote log segment
> > > > > metadata of
> > > > > > > that
> > > > > > > > > > > partition with a delete marker and publishes them to
> > RLMM."
> > > > > This
> > > > > > > seems
> > > > > > > > > > > outdated given the new topic deletion logic.
> > > > > > > > > > >
> > > > > > > > > > > 5111. "RLM follower fetches the earliest offset for the
> > > > > earliest
> > > > > > > leader
> > > > > > > > > > > epoch by calling RLMM.earliestLogOffset(TopicPartition
> > > > > > > topicPartition,
> > > > > > > > > int
> > > > > > > > > > > leaderEpoch) and updates that as the log start offset."
> > Do we
> > > > > need
> > > > > > > that
> > > > > > > > > > > since replication propagates logStartOffset already?
> > > > > > > > > > >
> > > > > > > > > > > 5112. Is the default maxWaitMs of 500ms enough for
> > fetching
> > > > > from
> > > > > > > remote
> > > > > > > > > > > storage?
> > > > > > > > > > >
> > > > > > > > > > > 5113. "Committed offsets can be stored in a local file to
> > > > avoid
> > > > > > > > > reading the
> > > > > > > > > > > messages again when a broker is restarted." Could you
> > > > describe
> > > > > the
> > > > > > > > > format
> > > > > > > > > > > and the location of the file? Also, could the same
> > message be
> > > > > > > > > processed by
> > > > > > > > > > > RLMM again after broker restart? If so, how do we handle
> > > > that?
> > > > > > > > > > >
> > > > > > > > > > > 5114. Message format
> > > > > > > > > > > 5114.1 There are two records named
> > > > > RemoteLogSegmentMetadataRecord
> > > > > > > with
> > > > > > > > > > > apiKey 0 and 1.
> > > > > > > > > > > 5114.2 RemoteLogSegmentMetadataRecord: Could we document
> > > > > whether
> > > > > > > > > endOffset
> > > > > > > > > > > is inclusive/exclusive?
> > > > > > > > > > > 5114.3 RemoteLogSegmentMetadataRecord: Could you explain
> > > > > > > LeaderEpoch a
> > > > > > > > > bit
> > > > > > > > > > > more? Is that the epoch of the leader when it copies the
> > > > > segment to
> > > > > > > > > remote
> > > > > > > > > > > storage? Also, how will this field be used?
> > > > > > > > > > > 5114.4 EventTimestamp: Could you explain this a bit more?
> > > > Each
> > > > > > > record
> > > > > > > > > in
> > > > > > > > > > > Kafka already has a timestamp field. Could we just use
> > that?
> > > > > > > > > > > 5114.5 SegmentSizeInBytes: Could this just be int32?
> > > > > > > > > > >
> > > > > > > > > > > 5115. RemoteLogCleaner(RLC): This could be confused with
> > the
> > > > > log
> > > > > > > > > cleaner
> > > > > > > > > > > for compaction. Perhaps it can be renamed to sth like
> > > > > > > > > > > RemotePartitionRemover.
> > > > > > > > > > >
> > > > > > > > > > > 5116. "RLC receives the delete_partition_marked and
> > processes
> > > > > it
> > > > > > > if it
> > > > > > > > > is
> > > > > > > > > > > not yet processed earlier." How does it know whether
> > > > > > > > > > > delete_partition_marked has been processed earlier?
> > > > > > > > > > >
> > > > > > > > > > > 5117. Should we add a new MessageFormatter to read the
> > tier
> > > > > > > metadata
> > > > > > > > > topic?
> > > > > > > > > > >
> > > > > > > > > > > 5118. "Maximum remote log reader thread pool task queue
> > size.
> > > > > If
> > > > > > > the
> > > > > > > > > task
> > > > > > > > > > > queue is full, broker will stop reading remote log
> > segments."
> > > > > What
> > > > > > > do
> > > > > > > > > we
> > > > > > > > > > > return to the fetch request in this case?
> > > > > > > > > > >
> > > > > > > > > > > 5119. It would be useful to list all things not
> > supported in
> > > > > the
> > > > > > > first
> > > > > > > > > > > version in a Future work or Limitations section. For
> > example,
> > > > > > > compacted
> > > > > > > > > > > topic, JBOD, changing remote.log.storage.enable from
> > true to
> > > > > false,
> > > > > > > > > etc.
> > > > > > > > > > >
> > > > > > > > > > > Thanks,
> > > > > > > > > > >
> > > > > > > > > > > Jun
> > > > > > > > > > >
> > > > > > > > > > > On Tue, Oct 27, 2020 at 5:57 PM Kowshik Prakasam <
> > > > > > > > > kprakasam@confluent.io>
> > > > > > > > > > > wrote:
> > > > > > > > > > >
> > > > > > > > > > > > Hi Satish,
> > > > > > > > > > > >
> > > > > > > > > > > > Thanks for the updates to the KIP. Here are my first
> > batch
> > > > of
> > > > > > > > > > > > comments/suggestions on the latest version of the KIP.
> > > > > > > > > > > >
> > > > > > > > > > > > 5012. In the RemoteStorageManager interface, there is
> > an
> > > > API
> > > > > > > defined
> > > > > > > > > for
> > > > > > > > > > > > each file type. For example, fetchOffsetIndex,
> > > > > > > fetchTimestampIndex
> > > > > > > > > etc. To
> > > > > > > > > > > > avoid the duplication, I'd suggest we can instead have
> > a
> > > > > FileType
> > > > > > > > > enum and
> > > > > > > > > > > > a common get API based on the FileType.
> > > > > > > > > > > >
> > > > > > > > > > > > 5013. There are some references to the Google doc in
> > the
> > > > > KIP. I
> > > > > > > > > wasn't sure
> > > > > > > > > > > > if the Google doc is expected to be in sync with the
> > > > > contents of
> > > > > > > the
> > > > > > > > > wiki.
> > > > > > > > > > > > Going forward, it seems easier if just the KIP is
> > > > maintained
> > > > > as
> > > > > > > the
> > > > > > > > > source
> > > > > > > > > > > > of truth. In this regard, could you please move all the
> > > > > > > references
> > > > > > > > > to the
> > > > > > > > > > > > Google doc, maybe to a separate References section at
> > the
> > > > > bottom
> > > > > > > of
> > > > > > > > > the
> > > > > > > > > > > > KIP?
> > > > > > > > > > > >
> > > > > > > > > > > > 5014. There are some TODO sections in the KIP. Would
> > these
> > > > be
> > > > > > > filled
> > > > > > > > > up in
> > > > > > > > > > > > future iterations?
> > > > > > > > > > > >
> > > > > > > > > > > > 5015. Under "Topic deletion lifecycle", I'm trying to
> > > > > understand
> > > > > > > why
> > > > > > > > > do we
> > > > > > > > > > > > need delete_partition_marked as well as the
> > > > > > > delete_partition_started
> > > > > > > > > > > > messages. I couldn't spot a drawback if supposing we
> > > > > simplified
> > > > > > > the
> > > > > > > > > design
> > > > > > > > > > > > such that the controller would only write
> > > > > > > delete_partition_started
> > > > > > > > > message,
> > > > > > > > > > > > and RemoteLogCleaner (RLC) instance picks it up for
> > > > > processing.
> > > > > > > What
> > > > > > > > > am I
> > > > > > > > > > > > missing?
> > > > > > > > > > > >
> > > > > > > > > > > > 5016. Under "Topic deletion lifecycle", step (4) is
> > > > > mentioned as
> > > > > > > > > "RLC gets
> > > > > > > > > > > > all the remote log segments for the partition and each
> > of
> > > > > these
> > > > > > > > > remote log
> > > > > > > > > > > > segments is deleted with the next steps.". Since the
> > RLC
> > > > > instance
> > > > > > > > > runs on
> > > > > > > > > > > > each tier topic partition leader, how does the RLC
> > then get
> > > > > the
> > > > > > > list
> > > > > > > > > of
> > > > > > > > > > > > remote log segments to be deleted? It will be useful
> > to add
> > > > > that
> > > > > > > > > detail to
> > > > > > > > > > > > the KIP.
> > > > > > > > > > > >
> > > > > > > > > > > > 5017. Under "Public Interfaces -> Configs", there is a
> > line
> > > > > > > > > mentioning "We
> > > > > > > > > > > > will support flipping remote.log.storage.enable in next
> > > > > > > versions."
> > > > > > > > > It will
> > > > > > > > > > > > be useful to mention this in the "Future Work" section
> > of
> > > > > the KIP
> > > > > > > > > too.
> > > > > > > > > > > >
> > > > > > > > > > > > 5018. The KIP introduces a number of configuration
> > > > > parameters. It
> > > > > > > > > will be
> > > > > > > > > > > > useful to mention in the KIP if the user should assume
> > > > these
> > > > > as
> > > > > > > > > static
> > > > > > > > > > > > configuration in the server.properties file, or dynamic
> > > > > > > > > configuration which
> > > > > > > > > > > > can be modified without restarting the broker.
> > > > > > > > > > > >
> > > > > > > > > > > > 5019.  Maybe this is planned as a future update to the
> > KIP,
> > > > > but I
> > > > > > > > > thought
> > > > > > > > > > > > I'd mention it here. Could you please add details to
> > the
> > > > KIP
> > > > > on
> > > > > > > why
> > > > > > > > > RocksDB
> > > > > > > > > > > > was chosen as the default cache implementation of
> > RLMM, and
> > > > > how
> > > > > > > it
> > > > > > > > > is going
> > > > > > > > > > > > to be used? Were alternatives compared/considered? For
> > > > > example,
> > > > > > > it
> > > > > > > > > would be
> > > > > > > > > > > > useful to explain/evaluate the following: 1)
> > debuggability
> > > > > of the
> > > > > > > > > RocksDB
> > > > > > > > > > > > JNI interface, 2) performance, 3) portability across
> > > > > platforms
> > > > > > > and 4)
> > > > > > > > > > > > interface parity of RocksDB’s JNI api with it's
> > underlying
> > > > > C/C++
> > > > > > > api.
> > > > > > > > > > > >
> > > > > > > > > > > > 5020. Following up on (5019), for the RocksDB cache, it
> > > > will
> > > > > be
> > > > > > > > > useful to
> > > > > > > > > > > > explain the relationship/mapping between the following
> > in
> > > > the
> > > > > > > KIP:
> > > > > > > > > 1) # of
> > > > > > > > > > > > tiered partitions, 2) # of partitions of metadata topic
> > > > > > > > > > > > __remote_log_metadata and 3) # of RocksDB instances.
> > i.e.
> > > > is
> > > > > the
> > > > > > > > > plan to
> > > > > > > > > > > > have a RocksDB instance per tiered partition, or per
> > > > metadata
> > > > > > > topic
> > > > > > > > > > > > partition, or just 1 for per broker?
> > > > > > > > > > > >
> > > > > > > > > > > > 5021. I was looking at the implementation prototype (PR
> > > > link:
> > > > > > > > > > > > https://github.com/apache/kafka/pull/7561). It seems
> > that
> > > > a
> > > > > > > boolean
> > > > > > > > > > > > attribute is being introduced into the Log layer to
> > check
> > > > if
> > > > > > > remote
> > > > > > > > > log
> > > > > > > > > > > > capability is enabled. While the boolean footprint is
> > small
> > > > > at
> > > > > > > the
> > > > > > > > > moment,
> > > > > > > > > > > > this can easily grow in the future and become harder to
> > > > > > > > > > > > test/maintain, considering that the Log layer is
> > already
> > > > > pretty
> > > > > > > > > complex. We
> > > > > > > > > > > > should start thinking about how to manage such changes
> > to
> > > > > the Log
> > > > > > > > > layer
> > > > > > > > > > > > (for the purpose of improved testability, better
> > separation
> > > > > of
> > > > > > > > > concerns and
> > > > > > > > > > > > readability). One proposal I have is to take a step
> > back
> > > > and
> > > > > > > define a
> > > > > > > > > > > > higher level Log interface. Then, the Broker code can
> > be
> > > > > changed
> > > > > > > to
> > > > > > > > > use
> > > > > > > > > > > > this interface. It can be changed such that only a
> > handle
> > > > to
> > > > > the
> > > > > > > > > interface
> > > > > > > > > > > > is exposed to other components (such as LogCleaner,
> > > > > > > ReplicaManager
> > > > > > > > > etc.)
> > > > > > > > > > > > and not the underlying Log object. This approach keeps
> > the
> > > > > user
> > > > > > > of
> > > > > > > > > the Log
> > > > > > > > > > > > layer agnostic of the whereabouts of the data.
> > Underneath
> > > > the
> > > > > > > > > interface,
> > > > > > > > > > > > the implementing classes can completely separate local
> > log
> > > > > > > > > capabilities
> > > > > > > > > > > > from the remote log. For example, the Log class can be
> > > > > > > simplified to
> > > > > > > > > only
> > > > > > > > > > > > manage logic surrounding local log segments and
> > metadata.
> > > > > > > > > Additionally, a
> > > > > > > > > > > > wrapper class can be provided (implementing the higher
> > > > level
> > > > > Log
> > > > > > > > > interface)
> > > > > > > > > > > > which will contain any/all logic surrounding tiered
> > data.
> > > > The
> > > > > > > wrapper
> > > > > > > > > > > > class will wrap around an instance of the Log class
> > > > > delegating
> > > > > > > the
> > > > > > > > > local
> > > > > > > > > > > > log logic to it. Finally, a handle to the wrapper
> > class can
> > > > > be
> > > > > > > > > exposed to
> > > > > > > > > > > > the other components wherever they need a handle to the
> > > > > higher
> > > > > > > level
> > > > > > > > > Log
> > > > > > > > > > > > interface.
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > Cheers,
> > > > > > > > > > > > Kowshik
> > > > > > > > > > > >
> > > > > > > > > > > > On Mon, Oct 26, 2020 at 9:52 PM Satish Duggana <
> > > > > > > > > satish.duggana@gmail.com>
> > > > > > > > > > > > wrote:
> > > > > > > > > > > >
> > > > > > > > > > > > > Hi,
> > > > > > > > > > > > > KIP is updated with 1) topic deletion lifecycle and
> > its
> > > > > related
> > > > > > > > > items
> > > > > > > > > > > > > 2) Protocol changes(mainly related to ListOffsets)
> > and
> > > > > other
> > > > > > > minor
> > > > > > > > > > > > > changes.
> > > > > > > > > > > > > Please go through them and let us know your comments.
> > > > > > > > > > > > >
> > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > Satish.
> > > > > > > > > > > > >
> > > > > > > > > > > > > On Mon, Sep 28, 2020 at 9:10 PM Satish Duggana <
> > > > > > > > > satish.duggana@gmail.com
> > > > > > > > > > > > >
> > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Hi Dhruvil,
> > > > > > > > > > > > > > Thanks for looking into the KIP and sending your
> > > > > comments.
> > > > > > > Sorry
> > > > > > > > > for
> > > > > > > > > > > > > > the late reply, missed it in the mail thread.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 1. Could you describe how retention would work with
> > > > this
> > > > > KIP
> > > > > > > and
> > > > > > > > > which
> > > > > > > > > > > > > > threads are responsible for driving this work? I
> > > > believe
> > > > > > > there
> > > > > > > > > are 3
> > > > > > > > > > > > > kinds
> > > > > > > > > > > > > > of retention processes we are looking at:
> > > > > > > > > > > > > >   (a) Regular retention for data in tiered storage
> > as
> > > > per
> > > > > > > > > configured `
> > > > > > > > > > > > > > retention.ms` / `retention.bytes`.
> > > > > > > > > > > > > >   (b) Local retention for data in local storage as
> > per
> > > > > > > > > configured `
> > > > > > > > > > > > > > local.log.retention.ms` /
> > `local.log.retention.bytes`
> > > > > > > > > > > > > >   (c) Possibly regular retention for data in local
> > > > > storage,
> > > > > > > if
> > > > > > > > > the
> > > > > > > > > > > > > tiering
> > > > > > > > > > > > > > task is lagging or for data that is below the log
> > start
> > > > > > > offset.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Local log retention is done by the existing log
> > cleanup
> > > > > > > tasks.
> > > > > > > > > These
> > > > > > > > > > > > > > are not done for segments that are not yet copied
> > to
> > > > > remote
> > > > > > > > > storage.
> > > > > > > > > > > > > > Remote log cleanup is done by the leader
> > partition’s
> > > > > RLMTask.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 2. When does a segment become eligible to be
> > tiered? Is
> > > > > it as
> > > > > > > > > soon as
> > > > > > > > > > > > the
> > > > > > > > > > > > > > segment is rolled and the end offset is less than
> > the
> > > > > last
> > > > > > > stable
> > > > > > > > > > > > offset
> > > > > > > > > > > > > as
> > > > > > > > > > > > > > mentioned in the KIP? I wonder if we need to
> > consider
> > > > > other
> > > > > > > > > parameters
> > > > > > > > > > > > > too,
> > > > > > > > > > > > > > like the highwatermark so that we are guaranteed
> > that
> > > > > what
> > > > > > > we are
> > > > > > > > > > > > tiering
> > > > > > > > > > > > > > has been committed to the log and accepted by the
> > ISR.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > AFAIK, last stable offset is always <=
> > highwatermark.
> > > > > This
> > > > > > > will
> > > > > > > > > make
> > > > > > > > > > > > > > sure we are always tiering the message segments
> > which
> > > > > have
> > > > > > > been
> > > > > > > > > > > > > > accepted by ISR and transactionally completed.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 3. The section on "Follower Fetch Scenarios" is
> > useful
> > > > > but
> > > > > > > is a
> > > > > > > > > bit
> > > > > > > > > > > > > > difficult to parse at the moment. It would be
> > useful to
> > > > > > > > > summarize the
> > > > > > > > > > > > > > changes we need in the ReplicaFetcher.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > It may become difficult for users to read/follow
> > if we
> > > > > add
> > > > > > > code
> > > > > > > > > changes
> > > > > > > > > > > > > here.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 4. Related to the above, it's a bit unclear how we
> > are
> > > > > > > planning
> > > > > > > > > on
> > > > > > > > > > > > > > restoring the producer state for a new replica.
> > Could
> > > > you
> > > > > > > expand
> > > > > > > > > on
> > > > > > > > > > > > that?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > It is mentioned in the KIP
> > BuildingRemoteLogAuxState is
> > > > > > > > > introduced to
> > > > > > > > > > > > > > build the state like leader epoch sequence and
> > producer
> > > > > > > snapshots
> > > > > > > > > > > > > > before it starts fetching the data from the
> > leader. We
> > > > > will
> > > > > > > make
> > > > > > > > > it
> > > > > > > > > > > > > > clear in the KIP.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5. Similarly, it would be worth summarizing the
> > > > behavior
> > > > > on
> > > > > > > > > unclean
> > > > > > > > > > > > > leader
> > > > > > > > > > > > > > election. There are several scenarios to consider
> > here:
> > > > > data
> > > > > > > > > loss from
> > > > > > > > > > > > > > local log, data loss from remote log, data loss
> > from
> > > > > metadata
> > > > > > > > > topic,
> > > > > > > > > > > > etc.
> > > > > > > > > > > > > > It's worth describing these in detail.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > We mentioned the cases about unclean leader
> > election in
> > > > > the
> > > > > > > > > follower
> > > > > > > > > > > > > > fetch scenarios.
> > > > > > > > > > > > > > If there are errors while fetching data from remote
> > > > > store or
> > > > > > > > > metadata
> > > > > > > > > > > > > > store, it will work the same way as it works with
> > local
> > > > > log.
> > > > > > > It
> > > > > > > > > > > > > > returns the error back to the caller. Please let us
> > > > know
> > > > > if
> > > > > > > I am
> > > > > > > > > > > > > > missing your point here.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 7. For a READ_COMMITTED FetchRequest, how do we
> > > > retrieve
> > > > > and
> > > > > > > > > return the
> > > > > > > > > > > > > > aborted transaction metadata?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > When a fetch for a remote log is accessed, we will
> > > > fetch
> > > > > > > aborted
> > > > > > > > > > > > > > transactions along with the segment if it is not
> > found
> > > > > in the
> > > > > > > > > local
> > > > > > > > > > > > > > index cache. This includes the case of transaction
> > > > index
> > > > > not
> > > > > > > > > existing
> > > > > > > > > > > > > > in the remote log segment. That means, the cache
> > entry
> > > > > can be
> > > > > > > > > empty or
> > > > > > > > > > > > > > have a list of aborted transactions.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 8. The `LogSegmentData` class assumes that we have
> > a
> > > > log
> > > > > > > segment,
> > > > > > > > > > > > offset
> > > > > > > > > > > > > > index, time index, transaction index, producer
> > snapshot
> > > > > and
> > > > > > > > > leader
> > > > > > > > > > > > epoch
> > > > > > > > > > > > > > index. How do we deal with cases where we do not
> > have
> > > > > one or
> > > > > > > > > more of
> > > > > > > > > > > > > these?
> > > > > > > > > > > > > > For example, we may not have a transaction index or
> > > > > producer
> > > > > > > > > snapshot
> > > > > > > > > > > > > for a
> > > > > > > > > > > > > > particular segment. The former is optional, and the
> > > > > latter is
> > > > > > > > > only kept
> > > > > > > > > > > > > for
> > > > > > > > > > > > > > up to the 3 latest segments.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > This is a good point,  we discussed this in the
> > last
> > > > > meeting.
> > > > > > > > > > > > > > Transaction index is optional and we will copy them
> > > > only
> > > > > if
> > > > > > > it
> > > > > > > > > exists.
> > > > > > > > > > > > > > We want to keep all the producer snapshots at each
> > log
> > > > > > > segment
> > > > > > > > > rolling
> > > > > > > > > > > > > > and they can be removed if the log copying is
> > > > successful
> > > > > and
> > > > > > > it
> > > > > > > > > still
> > > > > > > > > > > > > > maintains the existing latest 3 segments, We only
> > > > delete
> > > > > the
> > > > > > > > > producer
> > > > > > > > > > > > > > snapshots which have been copied to remote log
> > segments
> > > > > on
> > > > > > > > > leader.
> > > > > > > > > > > > > > Follower will keep the log segments beyond the
> > segments
> > > > > which
> > > > > > > > > have not
> > > > > > > > > > > > > > been copied to remote storage. We will update the
> > KIP
> > > > > with
> > > > > > > these
> > > > > > > > > > > > > > details.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > Satish.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > On Thu, Sep 17, 2020 at 1:47 AM Dhruvil Shah <
> > > > > > > > > dhruvil@confluent.io>
> > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Hi Satish, Harsha,
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Thanks for the KIP. Few questions below:
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 1. Could you describe how retention would work
> > with
> > > > > this
> > > > > > > KIP
> > > > > > > > > and
> > > > > > > > > > > > which
> > > > > > > > > > > > > > > threads are responsible for driving this work? I
> > > > > believe
> > > > > > > there
> > > > > > > > > are 3
> > > > > > > > > > > > > kinds
> > > > > > > > > > > > > > > of retention processes we are looking at:
> > > > > > > > > > > > > > >   (a) Regular retention for data in tiered
> > storage as
> > > > > per
> > > > > > > > > configured
> > > > > > > > > > > > `
> > > > > > > > > > > > > > > retention.ms` / `retention.bytes`.
> > > > > > > > > > > > > > >   (b) Local retention for data in local storage
> > as
> > > > per
> > > > > > > > > configured `
> > > > > > > > > > > > > > > local.log.retention.ms` /
> > > > `local.log.retention.bytes`
> > > > > > > > > > > > > > >   (c) Possibly regular retention for data in
> > local
> > > > > > > storage, if
> > > > > > > > > the
> > > > > > > > > > > > > tiering
> > > > > > > > > > > > > > > task is lagging or for data that is below the log
> > > > start
> > > > > > > offset.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 2. When does a segment become eligible to be
> > tiered?
> > > > > Is it
> > > > > > > as
> > > > > > > > > soon as
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > segment is rolled and the end offset is less
> > than the
> > > > > last
> > > > > > > > > stable
> > > > > > > > > > > > > offset as
> > > > > > > > > > > > > > > mentioned in the KIP? I wonder if we need to
> > consider
> > > > > other
> > > > > > > > > > > > parameters
> > > > > > > > > > > > > too,
> > > > > > > > > > > > > > > like the highwatermark so that we are guaranteed
> > that
> > > > > what
> > > > > > > we
> > > > > > > > > are
> > > > > > > > > > > > > tiering
> > > > > > > > > > > > > > > has been committed to the log and accepted by the
> > > > ISR.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 3. The section on "Follower Fetch Scenarios" is
> > > > useful
> > > > > but
> > > > > > > is
> > > > > > > > > a bit
> > > > > > > > > > > > > > > difficult to parse at the moment. It would be
> > useful
> > > > to
> > > > > > > > > summarize the
> > > > > > > > > > > > > > > changes we need in the ReplicaFetcher.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 4. Related to the above, it's a bit unclear how
> > we
> > > > are
> > > > > > > > > planning on
> > > > > > > > > > > > > > > restoring the producer state for a new replica.
> > Could
> > > > > you
> > > > > > > > > expand on
> > > > > > > > > > > > > that?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 5. Similarly, it would be worth summarizing the
> > > > > behavior on
> > > > > > > > > unclean
> > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > election. There are several scenarios to consider
> > > > here:
> > > > > > > data
> > > > > > > > > loss
> > > > > > > > > > > > from
> > > > > > > > > > > > > > > local log, data loss from remote log, data loss
> > from
> > > > > > > metadata
> > > > > > > > > topic,
> > > > > > > > > > > > > etc.
> > > > > > > > > > > > > > > It's worth describing these in detail.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 6. It would be useful to add details about how we
> > > > plan
> > > > > on
> > > > > > > using
> > > > > > > > > > > > > RocksDB in
> > > > > > > > > > > > > > > the default implementation of
> > > > > `RemoteLogMetadataManager`.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 7. For a READ_COMMITTED FetchRequest, how do we
> > > > > retrieve
> > > > > > > and
> > > > > > > > > return
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > aborted transaction metadata?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 8. The `LogSegmentData` class assumes that we
> > have a
> > > > > log
> > > > > > > > > segment,
> > > > > > > > > > > > > offset
> > > > > > > > > > > > > > > index, time index, transaction index, producer
> > > > > snapshot and
> > > > > > > > > leader
> > > > > > > > > > > > > epoch
> > > > > > > > > > > > > > > index. How do we deal with cases where we do not
> > have
> > > > > one
> > > > > > > or
> > > > > > > > > more of
> > > > > > > > > > > > > these?
> > > > > > > > > > > > > > > For example, we may not have a transaction index
> > or
> > > > > > > producer
> > > > > > > > > snapshot
> > > > > > > > > > > > > for a
> > > > > > > > > > > > > > > particular segment. The former is optional, and
> > the
> > > > > latter
> > > > > > > is
> > > > > > > > > only
> > > > > > > > > > > > > kept for
> > > > > > > > > > > > > > > up to the 3 latest segments.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > Dhruvil
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > On Mon, Sep 7, 2020 at 6:54 PM Harsha Ch <
> > > > > > > harsha.ch@gmail.com>
> > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Hi All,
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > We are all working through the last meeting
> > > > feedback.
> > > > > > > I'll
> > > > > > > > > cancel
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > > tomorrow 's meeting and we can meanwhile
> > continue
> > > > our
> > > > > > > > > discussion in
> > > > > > > > > > > > > mailing
> > > > > > > > > > > > > > > > list. We can start the regular meeting from
> > next
> > > > week
> > > > > > > > > onwards.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Harsha
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > On Fri, Sep 04, 2020 at 8:41 AM, Satish
> > Duggana <
> > > > > > > > > > > > > satish.duggana@gmail.com
> > > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Hi Jun,
> > > > > > > > > > > > > > > > > Thanks for your thorough review and comments.
> > > > > Please
> > > > > > > find
> > > > > > > > > the
> > > > > > > > > > > > > inline
> > > > > > > > > > > > > > > > > replies below.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 600. The topic deletion logic needs more
> > details.
> > > > > > > > > > > > > > > > > 600.1 The KIP mentions "The controller
> > considers
> > > > > the
> > > > > > > topic
> > > > > > > > > > > > > partition is
> > > > > > > > > > > > > > > > > deleted only when it determines that there
> > are no
> > > > > log
> > > > > > > > > segments
> > > > > > > > > > > > for
> > > > > > > > > > > > > that
> > > > > > > > > > > > > > > > > topic partition by using RLMM". How is this
> > done?
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > It uses RLMM#listSegments() returns all the
> > > > > segments
> > > > > > > for
> > > > > > > > > the
> > > > > > > > > > > > given
> > > > > > > > > > > > > topic
> > > > > > > > > > > > > > > > > partition.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 600.2 "If the delete option is enabled then
> > the
> > > > > leader
> > > > > > > > > will stop
> > > > > > > > > > > > > RLM task
> > > > > > > > > > > > > > > > > and stop processing and it sets all the
> > remote
> > > > log
> > > > > > > segment
> > > > > > > > > > > > > metadata of
> > > > > > > > > > > > > > > > > that partition with a delete marker and
> > publishes
> > > > > them
> > > > > > > to
> > > > > > > > > RLMM."
> > > > > > > > > > > > We
> > > > > > > > > > > > > > > > > discussed this earlier. When a topic is being
> > > > > deleted,
> > > > > > > > > there may
> > > > > > > > > > > > > not be a
> > > > > > > > > > > > > > > > > leader for the deleted partition.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > This is a good point. As suggested in the
> > > > meeting,
> > > > > we
> > > > > > > will
> > > > > > > > > add a
> > > > > > > > > > > > > separate
> > > > > > > > > > > > > > > > > section for topic/partition deletion
> > lifecycle
> > > > and
> > > > > this
> > > > > > > > > scenario
> > > > > > > > > > > > > will be
> > > > > > > > > > > > > > > > > addressed.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 601. Unclean leader election
> > > > > > > > > > > > > > > > > 601.1 Scenario 1: new empty follower
> > > > > > > > > > > > > > > > > After step 1, the follower restores up to
> > offset
> > > > > 3. So
> > > > > > > why
> > > > > > > > > does
> > > > > > > > > > > > it
> > > > > > > > > > > > > have
> > > > > > > > > > > > > > > > > LE-2 <
> > https://issues.apache.org/jira/browse/LE-2
> > > > >
> > > > > at
> > > > > > > > > offset 5?
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Nice catch. It was showing the leader epoch
> > > > fetched
> > > > > > > from
> > > > > > > > > the
> > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > storage. It should be shown with the
> > truncated
> > > > till
> > > > > > > offset
> > > > > > > > > 3.
> > > > > > > > > > > > > Updated the
> > > > > > > > > > > > > > > > > KIP.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 601.2 senario 5: After Step 3, leader A has
> > > > > > > inconsistent
> > > > > > > > > data
> > > > > > > > > > > > > between its
> > > > > > > > > > > > > > > > > local and the tiered data. For example.
> > offset 3
> > > > > has
> > > > > > > msg 3
> > > > > > > > > LE-0
> > > > > > > > > > > > > <https://issues.apache.org/jira/browse/LE-0>
> > locally,
> > > > > > > > > > > > > > > > > but msg 5 LE-1 <
> > > > > > > https://issues.apache.org/jira/browse/LE-1>
> > > > > > > > > in
> > > > > > > > > > > > > the remote store. While it's ok for the unclean
> > leader
> > > > > > > > > > > > > > > > > to lose data, it should still return
> > consistent
> > > > > data,
> > > > > > > > > whether
> > > > > > > > > > > > it's
> > > > > > > > > > > > > from
> > > > > > > > > > > > > > > > > the local or the remote store.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > There is no inconsistency here as LE-0
> > > > > > > > > > > > > <https://issues.apache.org/jira/browse/LE-0>
> > offsets are
> > > > > [0,
> > > > > > > 4]
> > > > > > > > > and LE-2
> > > > > > > > > > > > > <https://issues.apache.org/jira/browse/LE-2>:
> > > > > > > > > > > > > > > > > [5, ]. It will always get the right records
> > for
> > > > the
> > > > > > > given
> > > > > > > > > offset
> > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > leader epoch. In case of remote, RSM is
> > invoked
> > > > to
> > > > > get
> > > > > > > the
> > > > > > > > > remote
> > > > > > > > > > > > > log
> > > > > > > > > > > > > > > > > segment that contains the given offset with
> > the
> > > > > leader
> > > > > > > > > epoch.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 601.4 It seems that retention is based on
> > > > > > > > > > > > > > > > > listRemoteLogSegments(TopicPartition
> > > > > topicPartition,
> > > > > > > long
> > > > > > > > > > > > > leaderEpoch).
> > > > > > > > > > > > > > > > > When there is an unclean leader election,
> > it's
> > > > > possible
> > > > > > > > > for the
> > > > > > > > > > > > new
> > > > > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > > to not to include certain epochs in its epoch
> > > > > cache.
> > > > > > > How
> > > > > > > > > are
> > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > segments associated with those epochs being
> > > > > cleaned?
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > That is a good point. This leader will also
> > > > > cleanup the
> > > > > > > > > epochs
> > > > > > > > > > > > > earlier to
> > > > > > > > > > > > > > > > > its start leader epoch and delete those
> > segments.
> > > > > It
> > > > > > > gets
> > > > > > > > > the
> > > > > > > > > > > > > earliest
> > > > > > > > > > > > > > > > > epoch for a partition and starts deleting
> > > > segments
> > > > > from
> > > > > > > > > that
> > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > epoch.
> > > > > > > > > > > > > > > > > We need one more API in RLMM to get the
> > earliest
> > > > > leader
> > > > > > > > > epoch.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 601.5 The KIP discusses the handling of
> > unclean
> > > > > leader
> > > > > > > > > elections
> > > > > > > > > > > > > for user
> > > > > > > > > > > > > > > > > topics. What about unclean leader elections
> > on
> > > > > > > > > > > > > > > > > __remote_log_segment_metadata?
> > > > > > > > > > > > > > > > > This is the same as other system topics like
> > > > > > > > > consumer_offsets,
> > > > > > > > > > > > > > > > > __transaction_state topics. As discussed in
> > the
> > > > > > > meeting,
> > > > > > > > > we will
> > > > > > > > > > > > > add the
> > > > > > > > > > > > > > > > > behavior of __remote_log_segment_metadata
> > topic’s
> > > > > > > unclean
> > > > > > > > > leader
> > > > > > > > > > > > > > > > > truncation.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 602. It would be useful to clarify the
> > > > limitations
> > > > > in
> > > > > > > the
> > > > > > > > > initial
> > > > > > > > > > > > > > > > release.
> > > > > > > > > > > > > > > > > The KIP mentions not supporting compacted
> > topics.
> > > > > What
> > > > > > > > > about JBOD
> > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > changing the configuration of a topic from
> > delete
> > > > > to
> > > > > > > > > compact
> > > > > > > > > > > > after
> > > > > > > > > > > > > > > > remote.
> > > > > > > > > > > > > > > > > log. storage. enable (
> > > > > > > http://remote.log.storage.enable/
> > > > > > > > > ) is
> > > > > > > > > > > > > enabled?
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > This was updated in the KIP earlier.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 603. RLM leader tasks:
> > > > > > > > > > > > > > > > > 603.1"It checks for rolled over LogSegments
> > > > (which
> > > > > have
> > > > > > > > > the last
> > > > > > > > > > > > > message
> > > > > > > > > > > > > > > > > offset less than last stable offset of that
> > topic
> > > > > > > > > partition) and
> > > > > > > > > > > > > copies
> > > > > > > > > > > > > > > > > them along with their offset/time/transaction
> > > > > indexes
> > > > > > > and
> > > > > > > > > leader
> > > > > > > > > > > > > epoch
> > > > > > > > > > > > > > > > > cache to the remote tier." It needs to copy
> > the
> > > > > > > producer
> > > > > > > > > snapshot
> > > > > > > > > > > > > too.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Right. It copies producer snapshots too as
> > > > > mentioned in
> > > > > > > > > > > > > LogSegmentData.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 603.2 "Local logs are not cleaned up till
> > those
> > > > > > > segments
> > > > > > > > > are
> > > > > > > > > > > > copied
> > > > > > > > > > > > > > > > > successfully to remote even though their
> > > > retention
> > > > > > > > > time/size is
> > > > > > > > > > > > > reached"
> > > > > > > > > > > > > > > > > This seems weird. If the tiering stops
> > because
> > > > the
> > > > > > > remote
> > > > > > > > > store
> > > > > > > > > > > > is
> > > > > > > > > > > > > not
> > > > > > > > > > > > > > > > > available, we don't want the local data to
> > grow
> > > > > > > forever.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > It was clarified in the discussion that the
> > > > > comment was
> > > > > > > > > more
> > > > > > > > > > > > about
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > local storage goes beyond the log.retention.
> > The
> > > > > above
> > > > > > > > > statement
> > > > > > > > > > > > > is about
> > > > > > > > > > > > > > > > > local.log.retention but not for the complete
> > > > > > > > > log.retention. When
> > > > > > > > > > > > it
> > > > > > > > > > > > > > > > > reaches the log.retention then it will
> > delete the
> > > > > local
> > > > > > > > > logs even
> > > > > > > > > > > > > though
> > > > > > > > > > > > > > > > > those are not copied to remote storage.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 604. "RLM maintains a bounded cache(possibly
> > LRU)
> > > > > of
> > > > > > > the
> > > > > > > > > index
> > > > > > > > > > > > > files of
> > > > > > > > > > > > > > > > > remote log segments to avoid multiple index
> > > > fetches
> > > > > > > from
> > > > > > > > > the
> > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > storage. These indexes can be used in the
> > same
> > > > way
> > > > > as
> > > > > > > local
> > > > > > > > > > > > segment
> > > > > > > > > > > > > > > > > indexes are used." Could you provide more
> > details
> > > > > on
> > > > > > > this?
> > > > > > > > > Are
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > > indexes
> > > > > > > > > > > > > > > > > cached in memory or on disk? If on disk,
> > where
> > > > are
> > > > > they
> > > > > > > > > stored?
> > > > > > > > > > > > > Are the
> > > > > > > > > > > > > > > > > cached indexes bound by a certain size?
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > These are cached on disk and stored in
> > log.dir
> > > > > with a
> > > > > > > name
> > > > > > > > > > > > > > > > > “__remote_log_index_cache”. They are bound
> > by the
> > > > > total
> > > > > > > > > size.
> > > > > > > > > > > > This
> > > > > > > > > > > > > will
> > > > > > > > > > > > > > > > be
> > > > > > > > > > > > > > > > > exposed as a user configuration,
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 605. BuildingRemoteLogAux
> > > > > > > > > > > > > > > > > 605.1 In this section, two options are
> > listed.
> > > > > Which
> > > > > > > one is
> > > > > > > > > > > > chosen?
> > > > > > > > > > > > > > > > > Option-2, updated the KIP.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 605.2 In option 2, it says "Build the local
> > > > leader
> > > > > > > epoch
> > > > > > > > > cache by
> > > > > > > > > > > > > cutting
> > > > > > > > > > > > > > > > > the leader epoch sequence received from
> > remote
> > > > > storage
> > > > > > > to
> > > > > > > > > [LSO,
> > > > > > > > > > > > > ELO].
> > > > > > > > > > > > > > > > (LSO
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > = log start offset)." We need to do the same
> > > > thing
> > > > > for
> > > > > > > the
> > > > > > > > > > > > producer
> > > > > > > > > > > > > > > > > snapshot. However, it's hard to cut the
> > producer
> > > > > > > snapshot
> > > > > > > > > to an
> > > > > > > > > > > > > earlier
> > > > > > > > > > > > > > > > > offset. Another option is to simply take the
> > > > > lastOffset
> > > > > > > > > from the
> > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > > segment and use that as the starting fetch
> > offset
> > > > > in
> > > > > > > the
> > > > > > > > > > > > follower.
> > > > > > > > > > > > > This
> > > > > > > > > > > > > > > > > avoids the need for cutting.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Right, this was mentioned in the
> > “transactional
> > > > > > > support”
> > > > > > > > > section
> > > > > > > > > > > > > about
> > > > > > > > > > > > > > > > > adding these details.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 606. ListOffsets: Since we need a version
> > bump,
> > > > > could
> > > > > > > you
> > > > > > > > > > > > document
> > > > > > > > > > > > > it
> > > > > > > > > > > > > > > > > under a protocol change section?
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Sure, we will update the KIP.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 607. "LogStartOffset of a topic can point to
> > > > > either of
> > > > > > > > > local
> > > > > > > > > > > > > segment or
> > > > > > > > > > > > > > > > > remote segment but it is initialised and
> > > > > maintained in
> > > > > > > the
> > > > > > > > > Log
> > > > > > > > > > > > > class like
> > > > > > > > > > > > > > > > > now. This is already maintained in `Log`
> > class
> > > > > while
> > > > > > > > > loading the
> > > > > > > > > > > > > logs and
> > > > > > > > > > > > > > > > > it can also be fetched from
> > > > > RemoteLogMetadataManager."
> > > > > > > > > What will
> > > > > > > > > > > > > happen
> > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > the existing logic (e.g. log recovery) that
> > > > > currently
> > > > > > > > > depends on
> > > > > > > > > > > > > > > > > logStartOffset but assumes it's local?
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > They use a field called localLogStartOffset
> > which
> > > > > is
> > > > > > > the
> > > > > > > > > local
> > > > > > > > > > > > log
> > > > > > > > > > > > > start
> > > > > > > > > > > > > > > > > offset..
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 608. Handle expired remote segment: How does
> > it
> > > > > pick
> > > > > > > up new
> > > > > > > > > > > > > > > > logStartOffset
> > > > > > > > > > > > > > > > > from deleteRecords?
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Good point. This was not addressed in the
> > KIP.
> > > > Will
> > > > > > > update
> > > > > > > > > the
> > > > > > > > > > > > KIP
> > > > > > > > > > > > > on how
> > > > > > > > > > > > > > > > > the RLM task handles this scenario.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 609. RLMM message format:
> > > > > > > > > > > > > > > > > 609.1 It includes both MaxTimestamp and
> > > > > EventTimestamp.
> > > > > > > > > Where
> > > > > > > > > > > > does
> > > > > > > > > > > > > it get
> > > > > > > > > > > > > > > > > both since the message in the log only
> > contains
> > > > one
> > > > > > > > > timestamp?
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > `EventTimeStamp` is the timestamp at which
> > that
> > > > > segment
> > > > > > > > > metadata
> > > > > > > > > > > > > event is
> > > > > > > > > > > > > > > > > generated. This is more for audits.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 609.2 If we change just the state (e.g. to
> > > > > > > > > DELETE_STARTED), it
> > > > > > > > > > > > > seems it's
> > > > > > > > > > > > > > > > > wasteful to have to include all other fields
> > not
> > > > > > > changed.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > This is a good point. We thought about
> > > > incremental
> > > > > > > > > updates. But
> > > > > > > > > > > > we
> > > > > > > > > > > > > want
> > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > make sure all the events are in the expected
> > > > order
> > > > > and
> > > > > > > take
> > > > > > > > > > > > action
> > > > > > > > > > > > > based
> > > > > > > > > > > > > > > > > on the latest event. Will think through the
> > > > > approaches
> > > > > > > in
> > > > > > > > > detail
> > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > update here.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 609.3 Could you document which process makes
> > the
> > > > > > > following
> > > > > > > > > > > > > transitions
> > > > > > > > > > > > > > > > > DELETE_MARKED, DELETE_STARTED,
> > DELETE_FINISHED?
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Okay, will document more details.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 610. remote.log.reader.max.pending.tasks:
> > > > "Maximum
> > > > > > > remote
> > > > > > > > > log
> > > > > > > > > > > > > reader
> > > > > > > > > > > > > > > > > thread pool task queue size. If the task
> > queue is
> > > > > full,
> > > > > > > > > broker
> > > > > > > > > > > > > will stop
> > > > > > > > > > > > > > > > > reading remote log segments." What does the
> > > > broker
> > > > > do
> > > > > > > if
> > > > > > > > > the
> > > > > > > > > > > > queue
> > > > > > > > > > > > > is
> > > > > > > > > > > > > > > > > full?
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > It returns an error for this topic partition.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 611. What do we return if the request
> > > > offset/epoch
> > > > > > > doesn't
> > > > > > > > > exist
> > > > > > > > > > > > > in the
> > > > > > > > > > > > > > > > > following API?
> > > > > > > > > > > > > > > > > RemoteLogSegmentMetadata
> > > > > > > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > > > > > > > > > topicPartition, long offset, int
> > epochForOffset)
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > This returns null. But we prefer to update
> > the
> > > > > return
> > > > > > > type
> > > > > > > > > as
> > > > > > > > > > > > > Optional
> > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > return Empty if that does not exist.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > > Satish.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > On Tue, Sep 1, 2020 at 9:45 AM Jun Rao < jun@
> > > > > > > confluent.
> > > > > > > > > io (
> > > > > > > > > > > > > > > > > jun@confluent.io ) > wrote:
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >> Hi, Satish,
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >> Thanks for the updated KIP. Made another
> > pass. A
> > > > > few
> > > > > > > more
> > > > > > > > > > > > comments
> > > > > > > > > > > > > > > > below.
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >> 600. The topic deletion logic needs more
> > > > details.
> > > > > > > > > > > > > > > > >> 600.1 The KIP mentions "The controller
> > considers
> > > > > the
> > > > > > > topic
> > > > > > > > > > > > > partition is
> > > > > > > > > > > > > > > > >> deleted only when it determines that there
> > are
> > > > no
> > > > > log
> > > > > > > > > segments
> > > > > > > > > > > > > for that
> > > > > > > > > > > > > > > > >> topic partition by using RLMM". How is this
> > > > done?
> > > > > > > 600.2
> > > > > > > > > "If the
> > > > > > > > > > > > > delete
> > > > > > > > > > > > > > > > >> option is enabled then the leader will stop
> > RLM
> > > > > task
> > > > > > > and
> > > > > > > > > stop
> > > > > > > > > > > > > processing
> > > > > > > > > > > > > > > > >> and it sets all the remote log segment
> > metadata
> > > > of
> > > > > > > that
> > > > > > > > > > > > partition
> > > > > > > > > > > > > with a
> > > > > > > > > > > > > > > > >> delete marker and publishes them to RLMM."
> > We
> > > > > > > discussed
> > > > > > > > > this
> > > > > > > > > > > > > earlier.
> > > > > > > > > > > > > > > > When
> > > > > > > > > > > > > > > > >> a topic is being deleted, there may not be a
> > > > > leader
> > > > > > > for
> > > > > > > > > the
> > > > > > > > > > > > > deleted
> > > > > > > > > > > > > > > > >> partition.
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >> 601. Unclean leader election
> > > > > > > > > > > > > > > > >> 601.1 Scenario 1: new empty follower
> > > > > > > > > > > > > > > > >> After step 1, the follower restores up to
> > offset
> > > > > 3. So
> > > > > > > > > why does
> > > > > > > > > > > > > it have
> > > > > > > > > > > > > > > > >> LE-2 <
> > > > https://issues.apache.org/jira/browse/LE-2>
> > > > > at
> > > > > > > > > offset 5?
> > > > > > > > > > > > > > > > >> 601.2 senario 5: After Step 3, leader A has
> > > > > > > inconsistent
> > > > > > > > > data
> > > > > > > > > > > > > between
> > > > > > > > > > > > > > > > its
> > > > > > > > > > > > > > > > >> local and the tiered data. For example.
> > offset 3
> > > > > has
> > > > > > > msg
> > > > > > > > > 3 LE-0
> > > > > > > > > > > > > <https://issues.apache.org/jira/browse/LE-0>
> > locally,
> > > > > > > > > > > > > > > > >> but msg 5 LE-1 <
> > > > > > > > > https://issues.apache.org/jira/browse/LE-1> in
> > > > > > > > > > > > > the remote store. While it's ok for the unclean
> > leader
> > > > > > > > > > > > > > > > >> to lose data, it should still return
> > consistent
> > > > > data,
> > > > > > > > > whether
> > > > > > > > > > > > > it's from
> > > > > > > > > > > > > > > > >> the local or the remote store.
> > > > > > > > > > > > > > > > >> 601.3 The follower picks up log start offset
> > > > > using the
> > > > > > > > > following
> > > > > > > > > > > > > api.
> > > > > > > > > > > > > > > > >> Suppose that we have 3 remote segments (LE,
> > > > > > > > > SegmentStartOffset)
> > > > > > > > > > > > > as (2,
> > > > > > > > > > > > > > > > >> 10),
> > > > > > > > > > > > > > > > >> (3, 20) and (7, 15) due to an unclean leader
> > > > > election.
> > > > > > > > > Using the
> > > > > > > > > > > > > > > > following
> > > > > > > > > > > > > > > > >> api will cause logStartOffset to go backward
> > > > from
> > > > > 20
> > > > > > > to
> > > > > > > > > 15. How
> > > > > > > > > > > > > do we
> > > > > > > > > > > > > > > > >> prevent that?
> > > > > > > > > > > > > > > > >> earliestLogOffset(TopicPartition
> > topicPartition,
> > > > > int
> > > > > > > > > > > > leaderEpoch)
> > > > > > > > > > > > > 601.4
> > > > > > > > > > > > > > > > It
> > > > > > > > > > > > > > > > >> seems that retention is based on
> > > > > > > > > > > > > > > > >> listRemoteLogSegments(TopicPartition
> > > > > topicPartition,
> > > > > > > long
> > > > > > > > > > > > > leaderEpoch).
> > > > > > > > > > > > > > > > >> When there is an unclean leader election,
> > it's
> > > > > > > possible
> > > > > > > > > for the
> > > > > > > > > > > > > new
> > > > > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > >> to not to include certain epochs in its
> > epoch
> > > > > cache.
> > > > > > > How
> > > > > > > > > are
> > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > >> segments associated with those epochs being
> > > > > cleaned?
> > > > > > > > > 601.5 The
> > > > > > > > > > > > KIP
> > > > > > > > > > > > > > > > >> discusses the handling of unclean leader
> > > > > elections for
> > > > > > > > > user
> > > > > > > > > > > > > topics. What
> > > > > > > > > > > > > > > > >> about unclean leader elections on
> > > > > > > > > > > > > > > > >> __remote_log_segment_metadata?
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >> 602. It would be useful to clarify the
> > > > > limitations in
> > > > > > > the
> > > > > > > > > > > > initial
> > > > > > > > > > > > > > > > release.
> > > > > > > > > > > > > > > > >> The KIP mentions not supporting compacted
> > > > topics.
> > > > > What
> > > > > > > > > about
> > > > > > > > > > > > JBOD
> > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > >> changing the configuration of a topic from
> > > > delete
> > > > > to
> > > > > > > > > compact
> > > > > > > > > > > > after
> > > > > > > > > > > > > > > > remote.
> > > > > > > > > > > > > > > > >> log. storage. enable (
> > > > > > > http://remote.log.storage.enable/
> > > > > > > > > ) is
> > > > > > > > > > > > > enabled?
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >> 603. RLM leader tasks:
> > > > > > > > > > > > > > > > >> 603.1"It checks for rolled over LogSegments
> > > > (which
> > > > > > > have
> > > > > > > > > the last
> > > > > > > > > > > > > message
> > > > > > > > > > > > > > > > >> offset less than last stable offset of that
> > > > topic
> > > > > > > > > partition) and
> > > > > > > > > > > > > copies
> > > > > > > > > > > > > > > > >> them along with their
> > offset/time/transaction
> > > > > indexes
> > > > > > > and
> > > > > > > > > leader
> > > > > > > > > > > > > epoch
> > > > > > > > > > > > > > > > >> cache to the remote tier." It needs to copy
> > the
> > > > > > > producer
> > > > > > > > > > > > snapshot
> > > > > > > > > > > > > too.
> > > > > > > > > > > > > > > > >> 603.2 "Local logs are not cleaned up till
> > those
> > > > > > > segments
> > > > > > > > > are
> > > > > > > > > > > > > copied
> > > > > > > > > > > > > > > > >> successfully to remote even though their
> > > > retention
> > > > > > > > > time/size is
> > > > > > > > > > > > > reached"
> > > > > > > > > > > > > > > > >> This seems weird. If the tiering stops
> > because
> > > > the
> > > > > > > remote
> > > > > > > > > store
> > > > > > > > > > > > > is not
> > > > > > > > > > > > > > > > >> available, we don't want the local data to
> > grow
> > > > > > > forever.
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >> 604. "RLM maintains a bounded cache(possibly
> > > > LRU)
> > > > > of
> > > > > > > the
> > > > > > > > > index
> > > > > > > > > > > > > files of
> > > > > > > > > > > > > > > > >> remote log segments to avoid multiple index
> > > > > fetches
> > > > > > > from
> > > > > > > > > the
> > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > >> storage. These indexes can be used in the
> > same
> > > > > way as
> > > > > > > > > local
> > > > > > > > > > > > > segment
> > > > > > > > > > > > > > > > >> indexes are used." Could you provide more
> > > > details
> > > > > on
> > > > > > > > > this? Are
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > > indexes
> > > > > > > > > > > > > > > > >> cached in memory or on disk? If on disk,
> > where
> > > > are
> > > > > > > they
> > > > > > > > > stored?
> > > > > > > > > > > > > Are the
> > > > > > > > > > > > > > > > >> cached indexes bound by a certain size?
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >> 605. BuildingRemoteLogAux
> > > > > > > > > > > > > > > > >> 605.1 In this section, two options are
> > listed.
> > > > > Which
> > > > > > > one
> > > > > > > > > is
> > > > > > > > > > > > > chosen?
> > > > > > > > > > > > > > > > 605.2
> > > > > > > > > > > > > > > > >> In option 2, it says "Build the local leader
> > > > epoch
> > > > > > > cache
> > > > > > > > > by
> > > > > > > > > > > > > cutting the
> > > > > > > > > > > > > > > > >> leader epoch sequence received from remote
> > > > > storage to
> > > > > > > > > [LSO,
> > > > > > > > > > > > ELO].
> > > > > > > > > > > > > (LSO
> > > > > > > > > > > > > > > > >> = log start offset)." We need to do the same
> > > > thing
> > > > > > > for the
> > > > > > > > > > > > > producer
> > > > > > > > > > > > > > > > >> snapshot. However, it's hard to cut the
> > producer
> > > > > > > snapshot
> > > > > > > > > to an
> > > > > > > > > > > > > earlier
> > > > > > > > > > > > > > > > >> offset. Another option is to simply take the
> > > > > > > lastOffset
> > > > > > > > > from the
> > > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > >> segment and use that as the starting fetch
> > > > offset
> > > > > in
> > > > > > > the
> > > > > > > > > > > > > follower. This
> > > > > > > > > > > > > > > > >> avoids the need for cutting.
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >> 606. ListOffsets: Since we need a version
> > bump,
> > > > > could
> > > > > > > you
> > > > > > > > > > > > > document it
> > > > > > > > > > > > > > > > >> under a protocol change section?
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >> 607. "LogStartOffset of a topic can point to
> > > > > either of
> > > > > > > > > local
> > > > > > > > > > > > > segment or
> > > > > > > > > > > > > > > > >> remote segment but it is initialised and
> > > > > maintained in
> > > > > > > > > the Log
> > > > > > > > > > > > > class
> > > > > > > > > > > > > > > > like
> > > > > > > > > > > > > > > > >> now. This is already maintained in `Log`
> > class
> > > > > while
> > > > > > > > > loading the
> > > > > > > > > > > > > logs
> > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > >> it can also be fetched from
> > > > > RemoteLogMetadataManager."
> > > > > > > > > What will
> > > > > > > > > > > > > happen
> > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > >> the existing logic (e.g. log recovery) that
> > > > > currently
> > > > > > > > > depends on
> > > > > > > > > > > > > > > > >> logStartOffset but assumes it's local?
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >> 608. Handle expired remote segment: How
> > does it
> > > > > pick
> > > > > > > up
> > > > > > > > > new
> > > > > > > > > > > > > > > > logStartOffset
> > > > > > > > > > > > > > > > >> from deleteRecords?
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >> 609. RLMM message format:
> > > > > > > > > > > > > > > > >> 609.1 It includes both MaxTimestamp and
> > > > > > > EventTimestamp.
> > > > > > > > > Where
> > > > > > > > > > > > > does it
> > > > > > > > > > > > > > > > get
> > > > > > > > > > > > > > > > >> both since the message in the log only
> > contains
> > > > > one
> > > > > > > > > timestamp?
> > > > > > > > > > > > > 609.2 If
> > > > > > > > > > > > > > > > we
> > > > > > > > > > > > > > > > >> change just the state (e.g. to
> > DELETE_STARTED),
> > > > it
> > > > > > > seems
> > > > > > > > > it's
> > > > > > > > > > > > > wasteful
> > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > >> have to include all other fields not
> > changed.
> > > > > 609.3
> > > > > > > Could
> > > > > > > > > you
> > > > > > > > > > > > > document
> > > > > > > > > > > > > > > > >> which process makes the following
> > transitions
> > > > > > > > > DELETE_MARKED,
> > > > > > > > > > > > > > > > >> DELETE_STARTED, DELETE_FINISHED?
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >> 610. remote.log.reader.max.pending.tasks:
> > > > "Maximum
> > > > > > > remote
> > > > > > > > > log
> > > > > > > > > > > > > reader
> > > > > > > > > > > > > > > > >> thread pool task queue size. If the task
> > queue
> > > > is
> > > > > > > full,
> > > > > > > > > broker
> > > > > > > > > > > > > will stop
> > > > > > > > > > > > > > > > >> reading remote log segments." What does the
> > > > > broker do
> > > > > > > if
> > > > > > > > > the
> > > > > > > > > > > > > queue is
> > > > > > > > > > > > > > > > >> full?
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >> 611. What do we return if the request
> > > > offset/epoch
> > > > > > > > > doesn't exist
> > > > > > > > > > > > > in the
> > > > > > > > > > > > > > > > >> following API?
> > > > > > > > > > > > > > > > >> RemoteLogSegmentMetadata
> > > > > > > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > > > > > > > > >> topicPartition, long offset, int
> > epochForOffset)
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >> Jun
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >> On Mon, Aug 31, 2020 at 11:19 AM Satish
> > Duggana
> > > > <
> > > > > > > satish.
> > > > > > > > > > > > duggana@
> > > > > > > > > > > > > > > > gmail. com
> > > > > > > > > > > > > > > > >> ( satish.duggana@gmail.com ) > wrote:
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>> KIP is updated with
> > > > > > > > > > > > > > > > >>> - Remote log segment metadata topic message
> > > > > > > > > format/schema.
> > > > > > > > > > > > > > > > >>> - Added remote log segment metadata state
> > > > > > > transitions and
> > > > > > > > > > > > > explained how
> > > > > > > > > > > > > > > > >>> the deletion of segments is handled,
> > including
> > > > > the
> > > > > > > case
> > > > > > > > > of
> > > > > > > > > > > > > partition
> > > > > > > > > > > > > > > > >>> deletions.
> > > > > > > > > > > > > > > > >>> - Added a few more limitations in the "Non
> > > > goals"
> > > > > > > > > section.
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>> Thanks,
> > > > > > > > > > > > > > > > >>> Satish.
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>> On Thu, Aug 27, 2020 at 12:42 AM Harsha Ch
> > <
> > > > > harsha.
> > > > > > > ch@
> > > > > > > > > > > > gmail.
> > > > > > > > > > > > > com (
> > > > > > > > > > > > > > > > >>> harsha.ch@gmail.com ) > wrote:
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>> Updated the KIP with Meeting Notes section
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>> https:/ / cwiki. apache. org/ confluence/
> > > > > display/
> > > > > > > KAFKA/
> > > > > > > > > > > > > > > > KIP-405 <
> > > > > https://issues.apache.org/jira/browse/KIP-405>
> > > > > > > > > > > > >
> > > > > %3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> > > > > > > > > > > > > > > > >>> (
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > >
> > > > > > >
> > > > >
> > > >
> > https://cwiki.apache.org/confluence/display/KAFKA/KIP-405%3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> > > > > > > > > > > > > > > > >>> )
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>> On Tue, Aug 25, 2020 at 1:03 PM Jun Rao <
> > jun@
> > > > > > > > > confluent. io
> > > > > > > > > > > > (
> > > > > > > > > > > > > > > > >>>> jun@confluent.io ) > wrote:
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>> Hi, Harsha,
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>> Thanks for the summary. Could you add the
> > > > > summary
> > > > > > > and
> > > > > > > > > the
> > > > > > > > > > > > > recording
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>> link to
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>> the last section of
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>> https:/ / cwiki. apache. org/ confluence/
> > > > > display/
> > > > > > > KAFKA/
> > > > > > > > > > > > > > > > Kafka+Improvement+Proposals
> > > > > > > > > > > > > > > > >>> (
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > >
> > > > > > >
> > > > >
> > > >
> > https://cwiki.apache.org/confluence/display/KAFKA/Kafka+Improvement+Proposals
> > > > > > > > > > > > > > > > >>> )
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>> ?
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>> Jun
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>> On Tue, Aug 25, 2020 at 11:12 AM Harsha
> > > > > > > Chintalapani <
> > > > > > > > > kafka@
> > > > > > > > > > > > > > > > harsha. io (
> > > > > > > > > > > > > > > > >>>>> kafka@harsha.io ) > wrote:
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>> Thanks everyone for attending the
> > meeting
> > > > > today.
> > > > > > > > > > > > > > > > >>>>>> Here is the recording
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>> https:/ / drive. google. com/ file/ d/
> > > > > > > > > > > > > > > > 14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/
> > view?usp=sharing
> > > > > > > > > > > > > > > > >>> (
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > >
> > > > > > >
> > > > >
> > > >
> > https://drive.google.com/file/d/14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/view?usp=sharing
> > > > > > > > > > > > > > > > >>> )
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>> Notes:
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>> 1. KIP is updated with follower fetch
> > > > > protocol and
> > > > > > > > > ready to
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>> reviewed
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>> 2. Satish to capture schema of internal
> > > > > metadata
> > > > > > > > > topic in
> > > > > > > > > > > > the
> > > > > > > > > > > > > KIP
> > > > > > > > > > > > > > > > >>>>>> 3. We will update the KIP with details
> > of
> > > > > > > different
> > > > > > > > > cases
> > > > > > > > > > > > > > > > >>>>>> 4. Test plan will be captured in a doc
> > and
> > > > > will
> > > > > > > add
> > > > > > > > > to the
> > > > > > > > > > > > KIP
> > > > > > > > > > > > > > > > >>>>>> 5. Add a section "Limitations" to
> > capture
> > > > the
> > > > > > > > > capabilities
> > > > > > > > > > > > > that
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>> will
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>> be
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>> introduced with this KIP and what will
> > not
> > > > be
> > > > > > > covered
> > > > > > > > > in
> > > > > > > > > > > > this
> > > > > > > > > > > > > KIP.
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>> Please add to it I missed anything. Will
> > > > > produce a
> > > > > > > > > formal
> > > > > > > > > > > > > meeting
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>> notes
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>> from next meeting onwards.
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>> Thanks,
> > > > > > > > > > > > > > > > >>>>>> Harsha
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>> On Mon, Aug 24, 2020 at 9:42 PM, Ying
> > Zheng
> > > > <
> > > > > > > yingz@
> > > > > > > > > uber.
> > > > > > > > > > > > > com.
> > > > > > > > > > > > > > > > invalid (
> > > > > > > > > > > > > > > > >>>>>> yingz@uber.com.invalid ) > wrote:
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> We did some basic feature tests at
> > Uber.
> > > > The
> > > > > test
> > > > > > > > > cases and
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>> results are
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> shared in this google doc:
> > > > > > > > > > > > > > > > >>>>>>> https:/ / docs. google. com/
> > spreadsheets/
> > > > > d/ (
> > > > > > > > > > > > > > > > >>>>>>>
> > https://docs.google.com/spreadsheets/d/ )
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >
> > > > 1XhNJqjzwXvMCcAOhEH0sSXU6RTvyoSf93DHF-YMfGLk/edit?usp=sharing
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> The performance test results were
> > already
> > > > > shared
> > > > > > > in
> > > > > > > > > the KIP
> > > > > > > > > > > > > last
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>> month.
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> On Mon, Aug 24, 2020 at 11:10 AM
> > Harsha Ch
> > > > <
> > > > > > > harsha.
> > > > > > > > > ch@
> > > > > > > > > > > > > gmail.
> > > > > > > > > > > > > > > > com (
> > > > > > > > > > > > > > > > >>>>>>> harsha.ch@gmail.com ) >
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>> wrote:
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> "Understand commitments towards driving
> > > > > design &
> > > > > > > > > > > > > implementation of
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>> the
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>> KIP
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> further and how it aligns with
> > participant
> > > > > > > interests
> > > > > > > > > in
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>> contributing to
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>> the
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> efforts (ex: in the context of Uber’s
> > Q3/Q4
> > > > > > > > > roadmap)." What
> > > > > > > > > > > > > is that
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>> about?
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> On Mon, Aug 24, 2020 at 11:05 AM
> > Kowshik
> > > > > > > Prakasam <
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>> kprakasam@ confluent. io (
> > > > > kprakasam@confluent.io
> > > > > > > ) >
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> wrote:
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> Hi Harsha,
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> The following google doc contains a
> > > > proposal
> > > > > for
> > > > > > > > > temporary
> > > > > > > > > > > > > agenda
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>> for
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>> the
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> KIP-405 <
> > > > > > > > > https://issues.apache.org/jira/browse/KIP-405> <
> > > > > > > > > > > > > https:/ / issues. apache. org/ jira/ browse/ KIP-405
> > > > > > > > > > > > > <https://issues.apache.org/jira/browse/KIP-405> (
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > https://issues.apache.org/jira/browse/KIP-405 )
> > > > > > > >
> > > > > > > > > sync
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>> meeting
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> tomorrow:
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> https:/ / docs. google. com/ document/
> > d/ (
> > > > > > > > > > > > > > > > >>>>>>> https://docs.google.com/document/d/ )
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > 1pqo8X5LU8TpwfC_iqSuVPezhfCfhGkbGN2TqiPA3LBU/edit
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> .
> > > > > > > > > > > > > > > > >>>>>>> Please could you add it to the Google
> > > > > calendar
> > > > > > > > > invite?
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> Thank you.
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> Cheers,
> > > > > > > > > > > > > > > > >>>>>>> Kowshik
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> On Thu, Aug 20, 2020 at 10:58 AM
> > Harsha Ch
> > > > <
> > > > > > > harsha.
> > > > > > > > > ch@
> > > > > > > > > > > > > gmail.
> > > > > > > > > > > > > > > > com (
> > > > > > > > > > > > > > > > >>>>>>> harsha.ch@gmail.com ) >
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>> wrote:
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> Hi All,
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> Scheduled a meeting for Tuesday 9am -
> > 10am.
> > > > > I can
> > > > > > > > > record
> > > > > > > > > > > > and
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>> upload for
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> community to be able to follow the
> > > > > discussion.
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> Jun, please add the required folks on
> > > > > confluent
> > > > > > > side.
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> Thanks,
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> Harsha
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> On Thu, Aug 20, 2020 at 12:33 AM,
> > Alexandre
> > > > > > > Dupriez <
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>> alexandre.dupriez@
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> gmail. com ( http://gmail.com/ ) >
> > wrote:
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> Hi Jun,
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> Many thanks for your initiative.
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> If you like, I am happy to attend at
> > the
> > > > > time you
> > > > > > > > > > > > suggested.
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> Many thanks,
> > > > > > > > > > > > > > > > >>>>>>> Alexandre
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> Le mer. 19 août 2020 à 22:00, Harsha
> > Ch <
> > > > > > > harsha. ch@
> > > > > > > > > > > > > gmail. com (
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>> harsha.
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> ch@ gmail. com ( ch@gmail.com ) ) > a
> > > > écrit
> > > > > :
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> Hi Jun,
> > > > > > > > > > > > > > > > >>>>>>> Thanks. This will help a lot. Tuesday
> > will
> > > > > work
> > > > > > > for
> > > > > > > > > us.
> > > > > > > > > > > > > > > > >>>>>>> -Harsha
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> On Wed, Aug 19, 2020 at 1:24 PM Jun
> > Rao <
> > > > > jun@
> > > > > > > > > confluent.
> > > > > > > > > > > > > io (
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>> jun@
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> confluent. io ( http://confluent.io/
> > ) ) >
> > > > > > > wrote:
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> Hi, Satish, Ying, Harsha,
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> Do you think it would be useful to
> > have a
> > > > > regular
> > > > > > > > > virtual
> > > > > > > > > > > > > meeting
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>> to
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> discuss this KIP? The goal of the
> > meeting
> > > > > will be
> > > > > > > > > sharing
> > > > > > > > > > > > > > > > >>>>>>> design/development progress and
> > discussing
> > > > > any
> > > > > > > open
> > > > > > > > > issues
> > > > > > > > > > > > to
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> accelerate
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> this KIP. If so, will every Tuesday
> > (from
> > > > > next
> > > > > > > week)
> > > > > > > > > > > > 9am-10am
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> PT
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> work for you? I can help set up a Zoom
> > > > > meeting,
> > > > > > > > > invite
> > > > > > > > > > > > > everyone who
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> might
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> be interested, have it recorded and
> > shared,
> > > > > etc.
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> Thanks,
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> Jun
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> On Tue, Aug 18, 2020 at 11:01 AM Satish
> > > > > Duggana <
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> satish. duggana@ gmail. com ( satish.
> > > > > duggana@
> > > > > > > > > gmail. com
> > > > > > > > > > > > (
> > > > > > > > > > > > > > > > >>>>>>> satish.duggana@gmail.com ) ) >
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> wrote:
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> Hi Kowshik,
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> Thanks for looking into the KIP and
> > sending
> > > > > your
> > > > > > > > > comments.
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > > >>>>>>> 5001. Under the section "Follower fetch
> > > > > protocol
> > > > > > > in
> > > > > > > > > > > > detail",
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > >>>>>>> next-local-offset is the offset upto
> > which
> > > > > the
> > > > > > > > > segments are
> > > > > > > > > > > > > copied
> > > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > >
> > > > >
> > > >
> >

Re: [DISCUSS] KIP-405: Kafka Tiered Storage

[Jun Rao <ju...@confluent.io>]

Hi, Satish,

Thanks for the reply. A few more followup comments.

6000. Since we are returning new error codes, we need to bump up the
protocol version for Fetch request. Also, it will be useful to document all
new error codes and whether they are retriable or not.
This previous comment doesn't seem to be addressed.

9110. flat_file_format: Could you define the serialized representation for
each field in the header?

9111. RPM has the following 2 steps.
"1. The controller publishes delete_partition_marked event to say that the
partition is marked for deletion. There can be multiple events published
when the controller restarts or failover and this event will be
deduplicated by RPM.
2. RPM receives the delete_partition_marked and processes it if it is not
yet processed earlier."
What triggers RPM to read __remote_log_metadata? Is RPM part of the default
RLMM implementation or is it meant for any RLMM implementation?

9112. remote.log.manager.task.retry.backoff.ms: It would be useful to make
it clear in the comment that this is for the initial retry backoff.

9113. RLMM:
9113.1 updateRemoteLogSegmentMetadata(): This comment needs to be updated.
9113.2 Should RemoteLogSegmentMetadataUpdate include a leadeEpoch field
since all other update events have leaderEpoch?
9113.3 Could we rename RemotePartitionState to RemotePartitionDeleteState
to make it clear this is for deletion?
9113.4 Could we rename RemoteLogState to RemoteLogSegmentState to make it
clear this is for segment?

9114.Upgrade:
9114.1 It seems that we require message format > 0.11 for turning on the
remote store feature.
9114.2 It's not clear to me why remote.log.storage.system.enable needs to
be set to true before bumping up inter.broker.protocol.version.
9114.3 "If the topic-id is not received in the LeaderAndIsr request then
remote log storage will not start. But it will log an error message in the
log. One way to address this is to do a rolling restart of that broker, so
that the leader will be moved to another broker and the controller will
send LeaderAndIsr with the registered topic-id." Why is this needed? With
KIP-516, after upgrading to the latest protocol, topicIds are auto created.

9115. testing: Could you comment on how we plan to do integration and
system tests? Do we plan to include, for example, an in-memory
implementation of RSM?

9116. There is still a todo for the message formatter.

Jun

On Sat, Jan 9, 2021 at 2:04 AM Satish Duggana <sa...@gmail.com>
wrote:

> Hi Jun,
> Thanks for your comments. Please find the inline replies below.
>
> 6022. For packages used for server plugins, the convention is to
> use org.apache.kafka.server. See java-based Authorizer as an example.
>
> Sure, ‘org.apache.kafka.common.log.remote.storage’ renamed to
> ‘org.apache.kafka.server.log.remote.storage’.  Updated in the KIP.
>
> 9100. Do we need DeletePartitionStateRecord in flat_file_format? The flat
> file captures the state of the remote segments. After a partition is
> deleted, it seems that we just need to remove the partitions's remote
> segments from the flat file.
>
> DeletePartitionState might not yet have been processed by RPM and not
> completed. We  will not have  that in flat  file format  once it
> reaches DELETE_PARTITION_FINISHED state.
>
> 9101. Upgrade: It will be useful to allow direct upgrade from an old
> version. It seems that's doable. One can just do the normal upgrade first
> and wait enough time (for producer snapshots to be built), and then enable
> remote storage.
>
> Upgrade notes updates in the KIP.
>
> 9102. RemotePartitionRemover(RPM) process: Is it true that RPM starts
> tracking the remote segments when RLMM.onPartitionLeadershipChanges() is
> called with the broker being the leader for __remote_log_metadata
> partition? If so, could we document it?
>
> The current plan is to have that as part of RLMM and RPM uses that to
> get the remote segments list. I will add this detail in the respective
> sections.
>
> Satish.
>
> On Wed, 16 Dec 2020 at 23:55, Jun Rao <ju...@confluent.io> wrote:
> >
> > Hi, Satish,
> >
> > Thanks for the reply. A few more followup comments.
> >
> > 6022. For packages used for server plugins, the convention is to
> > use org.apache.kafka.server. See java-based Authorizer as an example.
> >
> > 9100. Do we need DeletePartitionStateRecord in flat_file_format? The flat
> > file captures the state of the remote segments. After a partition is
> > deleted, it seems that we just need to remove the partitions's remote
> > segments from the flat file.
> >
> > 9101. Upgrade: It will be useful to allow direct upgrade from an old
> > version. It seems that's doable. One can just do the normal upgrade first
> > and wait enough time (for producer snapshots to be built), and then
> enable
> > remote storage.
> >
> > 9102. RemotePartitionRemover(RPM) process: Is it true that RPM starts
> > tracking the remote segments when RLMM.onPartitionLeadershipChanges() is
> > called with the broker being the leader for __remote_log_metadata
> > partition? If so, could we document it?
> >
> > Jun
> >
> > On Tue, Dec 15, 2020 at 8:47 AM Kowshik Prakasam <kprakasam@confluent.io
> >
> > wrote:
> >
> > > Hi Satish,
> > >
> > > Thanks for the updates! A few more comments below.
> > >
> > > 9001. Under the "Upgrade" section, there is a line mentioning:
> "Upgrade the
> > > existing Kafka cluster to 2.7 version and allow this to run for the log
> > > retention of user topics that you want to enable tiered storage. This
> will
> > > allow all the topics to have the producer snapshots generated for each
> log
> > > segment." -- Which associated change in AK were you referring to here?
> Is
> > > it: https://github.com/apache/kafka/pull/7929 ? It seems like I don't
> see
> > > it in the 2.7 release branch yet, here is the link:
> > > https://github.com/apache/kafka/commits/2.7.
> > >
> > > 9002. Under the "Upgrade" section, the configuration mentioned is
> > > 'remote.log.storage.system.enable'. However, under "Public Interfaces"
> > > section the corresponding configuration is
> 'remote.storage.system.enable'.
> > > Could we use the same one in both, maybe
> > > 'remote.log.storage.system.enable'?
> > >
> > > 9003. Under "Per Topic Configuration", the KIP recommends setting
> > > 'remote.log.storage.enable' to true at a per-topic level. It will be
> useful
> > > to add a line that if the user wants to enable it for all topics, then
> they
> > > should be able to set the cluster-wide default to true. Also, it will
> be
> > > useful to mention that the KIP currently does not support setting it to
> > > false (after it is set to true), and add that to the future work
> section.
> > >
> > > 9004. Under "Committed offsets file format", the sample provided shows
> > > partition number and offset. Is the topic name required for identifying
> > > which topic the partitions belong to?
> > >
> > > 9005. Under "Internal flat-file store format of remote log metadata",
> it
> > > seems useful to specify both topic name and topic ID for debugging
> > > purposes.
> > >
> > > 9006. Under "Internal flat-file store format of remote log metadata",
> the
> > > description of "metadata-topic-offset" currently says "offset of the
> remote
> > > log metadata topic from which this topic partition's remote log
> metadata is
> > > fetched." Just for the wording, perhaps you meant to refer to the
> offset
> > > upto which the file has been committed? i.e. "offset of the remote log
> > > metadata topic upto which this topic partition's remote log metadata
> has
> > > been committed into this file."
> > >
> > > 9007. Under "Internal flat-file store format of remote log metadata",
> the
> > > schema of the payload (i.e. beyond the header) seems to contain the
> events
> > > from the metadata topic. It seems useful to instead persist the
> > > representation of the materialized state of the events, so that for the
> > > same segment only the latest state is stored. Besides reducing storage
> > > footprint, this also is likely to relate directly with the in-memory
> > > representation of the RLMM cache (which probably is some kind of a Map
> with
> > > key being segment ID and value being the segment state), so recovery
> from
> > > disk will be straightforward.
> > >
> > > 9008. Under "Topic deletion lifecycle", step (1), it will be useful to
> > > mention when in the deletion flow does the controller publish the
> > > delete_partition_marked event to say that the partition is marked for
> > > deletion?
> > >
> > > 9009. There are ~4 TODOs in the KIP. Could you please address these or
> > > remove them?
> > >
> > > 9010. There is a reference to a Google doc on the KIP which was used
> > > earlier for discussions. Please could you remove the reference, since
> the
> > > KIP is the source of the truth?
> > >
> > > 9011. This feedback is from an earlier comment. In the
> RemoteStorageManager
> > > interface, there is an API defined for each file type. For example,
> > > fetchOffsetIndex, fetchTimestampIndex etc. To avoid the duplication,
> I'd
> > > suggest we can instead have a FileType enum and a common get API based
> on
> > > the FileType. What do you think?
> > >
> > >
> > > Cheers,
> > > Kowshik
> > >
> > >
> > > On Mon, Dec 14, 2020 at 11:07 AM Satish Duggana <
> satish.duggana@gmail.com>
> > > wrote:
> > >
> > > > Hi Jun,
> > > > Thanks for your comments. Please go through the inline replies.
> > > >
> > > >
> > > > 5102.2: It seems that both positions can just be int. Another option
> is
> > > to
> > > > have two methods. Would it be clearer?
> > > >
> > > >     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> > > > remoteLogSegmentMetadata,  int startPosition)
> > > throwsRemoteStorageException;
> > > >
> > > >     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> > > > remoteLogSegmentMetadata, int startPosition, int endPosition) throws
> > > > RemoteStorageException;
> > > >
> > > > That makes sense to me, updated the KIP.
> > > >
> > > > 6003: Could you also update the javadoc for the return value?
> > > >
> > > > Updated.
> > > >
> > > > 6020: local.log.retention.bytes: Should it default to
> log.retention.bytes
> > > > to be consistent with local.log.retention.ms?
> > > >
> > > > Yes, it can be defaulted to log.retention.bytes.
> > > >
> > > > 6021: Could you define TopicIdPartition?
> > > >
> > > > Added TopicIdPartition in the KIP.
> > > >
> > > > 6022: For all public facing classes, could you specify the package
> name?
> > > >
> > > > Updated.
> > > >
> > > >
> > > > Thanks,
> > > > Satish.
> > > >
> > > > On Tue, Dec 8, 2020 at 12:59 AM Jun Rao <ju...@confluent.io> wrote:
> > > > >
> > > > > Hi, Satish,
> > > > >
> > > > > Thanks for the reply. A few more comments below.
> > > > >
> > > > > 5102.2: It seems that both positions can just be int. Another
> option is
> > > > to
> > > > > have two methods. Would it be clearer?
> > > > >
> > > > >     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> > > > > remoteLogSegmentMetadata,
> > > > >                                     int startPosition) throws
> > > > > RemoteStorageException;
> > > > >
> > > > >     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> > > > > remoteLogSegmentMetadata,
> > > > >                                     int startPosition, int
> endPosition)
> > > > > throws RemoteStorageException;
> > > > >
> > > > > 6003: Could you also update the javadoc for the return value?
> > > > >
> > > > > 6010: What kind of tiering throughput have you seen with 5 threads?
> > > > >
> > > > > 6020: local.log.retention.bytes: Should it default to
> > > log.retention.bytes
> > > > > to be consistent with local.log.retention.ms?
> > > > >
> > > > > 6021: Could you define TopicIdPartition?
> > > > >
> > > > > 6022: For all public facing classes, could you specify the package
> > > name?
> > > > >
> > > > > It seems that you already added the topicId support. Two other
> > > remaining
> > > > > items are (a) the format of local tier metadata storage and (b)
> > > upgrade.
> > > > >
> > > > > Jun
> > > > >
> > > > > On Mon, Dec 7, 2020 at 8:56 AM Satish Duggana <
> > > satish.duggana@gmail.com>
> > > > > wrote:
> > > > >
> > > > > > Hi Jun,
> > > > > > Thanks for your comments. Please find the inline replies below.
> > > > > >
> > > > > > >605.2 It's rare for the follower to need the remote data. So,
> the
> > > > current
> > > > > > approach is fine too. Could you document the process of
> rebuilding
> > > the
> > > > > > producer state since we can't simply trim the producerState to an
> > > > offset in
> > > > > > the middle of a segment.
> > > > > >
> > > > > > Will clarify in the KIP.
> > > > > >
> > > > > > >5102.2 Would it be clearer to make startPosiont long and
> endPosition
> > > > of
> > > > > > Optional<Long>?
> > > > > >
> > > > > > We will have arg checks with respective validation. It is not a
> good
> > > > > > practice to have arguments with optional as mentioned here.
> > > > > > https://rules.sonarsource.com/java/RSPEC-3553
> > > > > >
> > > > > >
> > > > > > >5102.5 LogSegmentData still has leaderEpochIndex as File
> instead of
> > > > > > ByteBuffer.
> > > > > >
> > > > > > Updated.
> > > > > >
> > > > > > >5102.7 Could you define all public methods for LogSegmentData?
> > > > > >
> > > > > > Updated.
> > > > > >
> > > > > > >5103.5 Could you change the reference to
> rlm_process_interval_ms and
> > > > > > rlm_retry_interval_ms to the new config names? Also, the retry
> > > interval
> > > > > > config seems still missing. It would be useful to support
> exponential
> > > > > > backoff with the retry interval config.
> > > > > >
> > > > > > Good point. We wanted the retry with truncated exponential
> backoff,
> > > > > > updated the KIP.
> > > > > >
> > > > > > >5111. "RLM follower fetches the earliest offset for the earliest
> > > > leader
> > > > > > epoch by calling RLMM.earliestLogOffset(TopicPartition
> > > topicPartition,
> > > > int
> > > > > > leaderEpoch) and updates that as the log start offset." This
> text is
> > > > still
> > > > > > there. Also, could we remove earliestLogOffset() from RLMM?
> > > > > >
> > > > > > Updated.
> > > > > >
> > > > > > >5115. There are still references to "remote log cleaners".
> > > > > >
> > > > > > Updated.
> > > > > >
> > > > > > >6000. Since we are returning new error codes, we need to bump
> up the
> > > > > > protocol version for Fetch request. Also, it will be useful to
> > > > document all
> > > > > > new error codes and whether they are retriable or not.
> > > > > >
> > > > > > Sure, we will add that in the KIP.
> > > > > >
> > > > > > >6001. public Map<Long, Long> segmentLeaderEpochs(): Currently,
> > > > leaderEpoch
> > > > > > is int32 instead of long.
> > > > > >
> > > > > > Updated.
> > > > > >
> > > > > > >6002. Is RemoteLogSegmentMetadata.markedForDeletion() needed
> given
> > > > > > RemoteLogSegmentMetadata.state()?
> > > > > >
> > > > > > No, it is fixed.
> > > > > >
> > > > > > >6003. RemoteLogSegmentMetadata
> > > remoteLogSegmentMetadata(TopicPartition
> > > > > > topicPartition, long offset, int epochForOffset): Should this
> return
> > > > > > Optional<RemoteLogSegmentMetadata>?
> > > > > >
> > > > > > That makes sense, updated.
> > > > > >
> > > > > > >6005. RemoteLogState: It seems it's better to split it between
> > > > > > DeletePartitionUpdate and RemoteLogSegmentMetadataUpdate since
> the
> > > > states
> > > > > > are never shared between the two use cases.
> > > > > >
> > > > > > Agree with that, updated.
> > > > > >
> > > > > > >6006. RLMM.onPartitionLeadershipChanges(): This may be ok.
> However,
> > > > is it
> > > > > > ture that other than the metadata topic, RLMM just needs to know
> > > > whether
> > > > > > there is a replica assigned to this broker and doesn't need to
> know
> > > > whether
> > > > > > the replica is the leader or the follower?
> > > > > >
> > > > > > That may be true. If the implementation does not need that, it
> can
> > > > > > ignore the information in the callback.
> > > > > >
> > > > > > >6007: "Handle expired remote segments (leader and follower)":
> Why is
> > > > this
> > > > > > needed in both the leader and the follower?
> > > > > >
> > > > > > Updated.
> > > > > >
> > > > > > >6008.       "name": "SegmentSizeInBytes",
> > > > > >                 "type": "int64",
> > > > > > The segment size can just be int32.
> > > > > >
> > > > > > Updated.
> > > > > >
> > > > > > >6009. For the record format in the log, it seems that we need
> to add
> > > > > > record
> > > > > > type and record version before the serialized bytes. We can
> follow
> > > the
> > > > > > convention used in
> > > > > >
> > > > > >
> > > >
> > >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-631%3A+The+Quorum-based+Kafka+Controller#KIP631:TheQuorumbasedKafkaController-RecordFormats
> > > > > >
> > > > > > Yes, KIP already mentions that these are serialized before the
> > > payload
> > > > > > as below. We will mention explicitly that these two are written
> > > before
> > > > > > the data is written.
> > > > > >
> > > > > > RLMM instance on broker publishes the message to the topic with
> key
> > > as
> > > > > > null and value with the below format.
> > > > > >
> > > > > > type      : unsigned var int, represents the value type. This
> value
> > > is
> > > > > > 'apikey' as mentioned in the schema.
> > > > > > version : unsigned var int, the 'version' number of the type as
> > > > > > mentioned in the schema.
> > > > > > data      : record payload in kafka protocol message format.
> > > > > >
> > > > > >
> > > > > > >6010. remote.log.manager.thread.pool.size: The default value is
> 10.
> > > > This
> > > > > > might be too high when enabling the tiered feature for the first
> > > time.
> > > > > > Since there are lots of segments that need to be tiered
> initially, a
> > > > large
> > > > > > number of threads could overwhelm the broker.
> > > > > >
> > > > > > Is the default value 5 reasonable?
> > > > > >
> > > > > > 6011. "The number of milli seconds to keep the local log segment
> > > > before it
> > > > > > gets deleted. If not set, the value in `log.retention.minutes` is
> > > > used. If
> > > > > > set to -1, no time limit is applied." We should use
> log.retention.ms
> > > > > > instead of log.retention.minutes.
> > > > > > Nice typo catch. Updated the KIP.
> > > > > >
> > > > > > Thanks,
> > > > > > Satish.
> > > > > >
> > > > > > On Thu, Dec 3, 2020 at 8:03 AM Jun Rao <ju...@confluent.io> wrote:
> > > > > > >
> > > > > > > Hi, Satish,
> > > > > > >
> > > > > > > Thanks for the updated KIP. A few more comments below.
> > > > > > >
> > > > > > > 605.2 It's rare for the follower to need the remote data. So,
> the
> > > > current
> > > > > > > approach is fine too. Could you document the process of
> rebuilding
> > > > the
> > > > > > > producer state since we can't simply trim the producerState to
> an
> > > > offset
> > > > > > in
> > > > > > > the middle of a segment.
> > > > > > >
> > > > > > > 5102.2 Would it be clearer to make startPosiont long and
> > > endPosition
> > > > of
> > > > > > > Optional<Long>?
> > > > > > >
> > > > > > > 5102.5 LogSegmentData still has leaderEpochIndex as File
> instead of
> > > > > > > ByteBuffer.
> > > > > > >
> > > > > > > 5102.7 Could you define all public methods for LogSegmentData?
> > > > > > >
> > > > > > > 5103.5 Could you change the reference to
> rlm_process_interval_ms
> > > and
> > > > > > > rlm_retry_interval_ms to the new config names? Also, the retry
> > > > interval
> > > > > > > config seems still missing. It would be useful to support
> > > exponential
> > > > > > > backoff with the retry interval config.
> > > > > > >
> > > > > > > 5111. "RLM follower fetches the earliest offset for the
> earliest
> > > > leader
> > > > > > > epoch by calling RLMM.earliestLogOffset(TopicPartition
> > > > topicPartition,
> > > > > > int
> > > > > > > leaderEpoch) and updates that as the log start offset." This
> text
> > > is
> > > > > > still
> > > > > > > there. Also, could we remove earliestLogOffset() from RLMM?
> > > > > > >
> > > > > > > 5115. There are still references to "remote log cleaners".
> > > > > > >
> > > > > > > 6000. Since we are returning new error codes, we need to bump
> up
> > > the
> > > > > > > protocol version for Fetch request. Also, it will be useful to
> > > > document
> > > > > > all
> > > > > > > new error codes and whether they are retriable or not.
> > > > > > >
> > > > > > > 6001. public Map<Long, Long> segmentLeaderEpochs(): Currently,
> > > > > > leaderEpoch
> > > > > > > is int32 instead of long.
> > > > > > >
> > > > > > > 6002. Is RemoteLogSegmentMetadata.markedForDeletion() needed
> given
> > > > > > > RemoteLogSegmentMetadata.state()?
> > > > > > >
> > > > > > > 6003. RemoteLogSegmentMetadata
> > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > topicPartition, long offset, int epochForOffset): Should this
> > > return
> > > > > > > Optional<RemoteLogSegmentMetadata>?
> > > > > > >
> > > > > > > 6004. DeletePartitionUpdate.epoch(): It would be useful to
> pick a
> > > > more
> > > > > > > indicative name so that people understand what epoch this is.
> > > > > > >
> > > > > > > 6005. RemoteLogState: It seems it's better to split it between
> > > > > > > DeletePartitionUpdate and RemoteLogSegmentMetadataUpdate since
> the
> > > > states
> > > > > > > are never shared between the two use cases.
> > > > > > >
> > > > > > > 6006. RLMM.onPartitionLeadershipChanges(): This may be ok.
> However,
> > > > is it
> > > > > > > ture that other than the metadata topic, RLMM just needs to
> know
> > > > whether
> > > > > > > there is a replica assigned to this broker and doesn't need to
> know
> > > > > > whether
> > > > > > > the replica is the leader or the follower?
> > > > > > >
> > > > > > > 6007: "Handle expired remote segments (leader and follower)":
> Why
> > > is
> > > > this
> > > > > > > needed in both the leader and the follower?
> > > > > > >
> > > > > > > 6008.       "name": "SegmentSizeInBytes",
> > > > > > >                 "type": "int64",
> > > > > > > The segment size can just be int32.
> > > > > > >
> > > > > > > 6009. For the record format in the log, it seems that we need
> to
> > > add
> > > > > > record
> > > > > > > type and record version before the serialized bytes. We can
> follow
> > > > the
> > > > > > > convention used in
> > > > > > >
> > > > > >
> > > >
> > >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-631%3A+The+Quorum-based+Kafka+Controller#KIP631:TheQuorumbasedKafkaController-RecordFormats
> > > > > > > .
> > > > > > >
> > > > > > > 6010. remote.log.manager.thread.pool.size: The default value
> is 10.
> > > > This
> > > > > > > might be too high when enabling the tiered feature for the
> first
> > > > time.
> > > > > > > Since there are lots of segments that need to be tiered
> initially,
> > > a
> > > > > > large
> > > > > > > number of threads could overwhelm the broker.
> > > > > > >
> > > > > > > 6011. "The number of milli seconds to keep the local log
> segment
> > > > before
> > > > > > it
> > > > > > > gets deleted. If not set, the value in `log.retention.minutes`
> is
> > > > used.
> > > > > > If
> > > > > > > set to -1, no time limit is applied." We should use
> > > log.retention.ms
> > > > > > > instead of log.retention.minutes.
> > > > > > >
> > > > > > > Jun
> > > > > > >
> > > > > > > On Tue, Dec 1, 2020 at 2:42 AM Satish Duggana <
> > > > satish.duggana@gmail.com>
> > > > > > > wrote:
> > > > > > >
> > > > > > > > Hi,
> > > > > > > > We updated the KIP with the points mentioned in the earlier
> mail
> > > > > > > > except for KIP-516 related changes. You can go through them
> and
> > > > let us
> > > > > > > > know if you have any comments. We will update the KIP with
> the
> > > > > > > > remaining todo items and KIP-516 related changes by end of
> this
> > > > > > > > week(5th Dec).
> > > > > > > >
> > > > > > > > Thanks,
> > > > > > > > Satish.
> > > > > > > >
> > > > > > > > On Tue, Nov 10, 2020 at 8:26 PM Satish Duggana <
> > > > > > satish.duggana@gmail.com>
> > > > > > > > wrote:
> > > > > > > > >
> > > > > > > > > Hi Jun,
> > > > > > > > > Thanks for your comments. Please find the inline replies
> below.
> > > > > > > > >
> > > > > > > > > 605.2 "Build the local leader epoch cache by cutting the
> leader
> > > > epoch
> > > > > > > > > sequence received from remote storage to [LSO, ELO]." I
> > > > mentioned an
> > > > > > > > issue
> > > > > > > > > earlier. Suppose the leader's local start offset is 100.
> The
> > > > follower
> > > > > > > > finds
> > > > > > > > > a remote segment covering offset range [80, 120). The
> > > > producerState
> > > > > > with
> > > > > > > > > this remote segment is up to offset 120. To trim the
> > > > producerState to
> > > > > > > > > offset 100 requires more work since one needs to download
> the
> > > > > > previous
> > > > > > > > > producerState up to offset 80 and then replay the messages
> from
> > > > 80 to
> > > > > > > > 100.
> > > > > > > > > It seems that it's simpler in this case for the follower
> just
> > > to
> > > > > > take the
> > > > > > > > > remote segment as it is and start fetching from offset 120.
> > > > > > > > >
> > > > > > > > > We chose that approach to avoid any edge cases here. It
> may be
> > > > > > > > > possible that the remote log segment that is received may
> not
> > > > have
> > > > > > the
> > > > > > > > > same leader epoch sequence from 100-120 as it contains on
> the
> > > > > > > > > leader(this can happen due to unclean leader). It is safe
> to
> > > > start
> > > > > > > > > from what the leader returns here.Another way is to find
> the
> > > > remote
> > > > > > > > > log segment
> > > > > > > > >
> > > > > > > > > 5016. Just to echo what Kowshik was saying. It seems that
> > > > > > > > > RLMM.onPartitionLeadershipChanges() is only called on the
> > > > replicas
> > > > > > for a
> > > > > > > > > partition, not on the replicas for the
> > > > __remote_log_segment_metadata
> > > > > > > > > partition. It's not clear how the leader of
> > > > > > __remote_log_segment_metadata
> > > > > > > > > obtains the metadata for remote segments for deletion.
> > > > > > > > >
> > > > > > > > > RLMM will always receive the callback for the remote log
> > > metadata
> > > > > > > > > topic partitions hosted on the local broker and these will
> be
> > > > > > > > > subscribed. I will make this clear in the KIP.
> > > > > > > > >
> > > > > > > > > 5100. KIP-516 has been accepted and is being implemented
> now.
> > > > Could
> > > > > > you
> > > > > > > > > update the KIP based on topicID?
> > > > > > > > >
> > > > > > > > > We mentioned KIP-516 and how it helps. We will update this
> KIP
> > > > with
> > > > > > > > > all the changes it brings with KIP-516.
> > > > > > > > >
> > > > > > > > > 5101. RLMM: It would be useful to clarify how the
> following two
> > > > APIs
> > > > > > are
> > > > > > > > > used. According to the wiki, the former is used for topic
> > > > deletion
> > > > > > and
> > > > > > > > the
> > > > > > > > > latter is used for retention. It seems that retention
> should
> > > use
> > > > the
> > > > > > > > former
> > > > > > > > > since remote segments without a matching epoch in the
> leader
> > > > > > (potentially
> > > > > > > > > due to unclean leader election) also need to be garbage
> > > > collected.
> > > > > > The
> > > > > > > > > latter seems to be used for the new leader to determine the
> > > last
> > > > > > tiered
> > > > > > > > > segment.
> > > > > > > > >     default Iterator<RemoteLogSegmentMetadata>
> > > > > > > > > listRemoteLogSegments(TopicPartition topicPartition)
> > > > > > > > >     Iterator<RemoteLogSegmentMetadata>
> > > > > > > > listRemoteLogSegments(TopicPartition
> > > > > > > > > topicPartition, long leaderEpoch);
> > > > > > > > >
> > > > > > > > > Right,.that is what we are currently doing. We will update
> the
> > > > > > > > > javadocs and wiki with that. Earlier, we did not want to
> remove
> > > > the
> > > > > > > > > segments which are not matched with leader epochs from the
> > > ladder
> > > > > > > > > partition as they may be used later by a replica which can
> > > > become a
> > > > > > > > > leader (unclean leader election) and refer those segments.
> But
> > > > that
> > > > > > > > > may leak these segments in remote storage until the topic
> > > > lifetime.
> > > > > > We
> > > > > > > > > decided to cleanup the segments with the oldest incase of
> size
> > > > based
> > > > > > > > > retention also.
> > > > > > > > >
> > > > > > > > > 5102. RSM:
> > > > > > > > > 5102.1 For methods like fetchLogSegmentData(), it seems
> that
> > > > they can
> > > > > > > > > use RemoteLogSegmentId instead of RemoteLogSegmentMetadata.
> > > > > > > > >
> > > > > > > > > It will be useful to have metadata for RSM to fetch log
> > > segment.
> > > > It
> > > > > > > > > may create location/path using id with other metadata too.
> > > > > > > > >
> > > > > > > > > 5102.2 In fetchLogSegmentData(), should we use long
> instead of
> > > > Long?
> > > > > > > > >
> > > > > > > > > Wanted to keep endPosition as optional to read till the
> end of
> > > > the
> > > > > > > > > segment and avoid sentinels.
> > > > > > > > >
> > > > > > > > > 5102.3 Why only some of the methods have default
> implementation
> > > > and
> > > > > > > > others
> > > > > > > > > Don't?
> > > > > > > > >
> > > > > > > > > Actually,  RSM will not have any default implementations.
> > > Those 3
> > > > > > > > > methods were made default earlier for tests etc. Updated
> the
> > > > wiki.
> > > > > > > > >
> > > > > > > > > 5102.4. Could we define RemoteLogSegmentMetadataUpdate
> > > > > > > > > and DeletePartitionUpdate?
> > > > > > > > >
> > > > > > > > > Sure, they will be added.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > 5102.5 LogSegmentData: It seems that it's easier to pass
> > > > > > > > > in leaderEpochIndex as a ByteBuffer or byte array than a
> file
> > > > since
> > > > > > it
> > > > > > > > will
> > > > > > > > > be generated in memory.
> > > > > > > > >
> > > > > > > > > Right, this is in plan.
> > > > > > > > >
> > > > > > > > > 5102.6 RemoteLogSegmentMetadata: It seems that it needs
> both
> > > > > > baseOffset
> > > > > > > > and
> > > > > > > > > startOffset. For example, deleteRecords() could move the
> > > > startOffset
> > > > > > to
> > > > > > > > the
> > > > > > > > > middle of a segment. If we copy the full segment to remote
> > > > storage,
> > > > > > the
> > > > > > > > > baseOffset and the startOffset will be different.
> > > > > > > > >
> > > > > > > > > Good point. startOffset is baseOffset by default, if not
> set
> > > > > > explicitly.
> > > > > > > > >
> > > > > > > > > 5102.7 Could we define all the public methods for
> > > > > > > > RemoteLogSegmentMetadata
> > > > > > > > > and LogSegmentData?
> > > > > > > > >
> > > > > > > > > Sure, updated the wiki.
> > > > > > > > >
> > > > > > > > > 5102.8 Could we document whether endOffset in
> > > > > > RemoteLogSegmentMetadata is
> > > > > > > > > inclusive/exclusive?
> > > > > > > > >
> > > > > > > > > It is inclusive, will update.
> > > > > > > > >
> > > > > > > > > 5103. configs:
> > > > > > > > > 5103.1 Could we define the default value of non-required
> > > configs
> > > > > > (e.g the
> > > > > > > > > size of new thread pools)?
> > > > > > > > >
> > > > > > > > > Sure, that makes sense.
> > > > > > > > >
> > > > > > > > > 5103.2 It seems that local.log.retention.ms should
> default to
> > > > > > > > retention.ms,
> > > > > > > > > instead of remote.log.retention.minutes. Similarly, it
> seems
> > > > > > > > > that local.log.retention.bytes should default to
> segment.bytes.
> > > > > > > > >
> > > > > > > > > Right, we do not have  remote.log.retention as we discussed
> > > > earlier.
> > > > > > > > > Thanks for catching the typo.
> > > > > > > > >
> > > > > > > > > 5103.3 remote.log.manager.thread.pool.size: The description
> > > says
> > > > > > "used in
> > > > > > > > > scheduling tasks to copy segments, fetch remote log
> indexes and
> > > > > > clean up
> > > > > > > > > remote log segments". However, there is a separate
> > > > > > > > > config remote.log.reader.threads for fetching remote data.
> It's
> > > > > > weird to
> > > > > > > > > fetch remote index and log in different thread pools since
> both
> > > > are
> > > > > > used
> > > > > > > > > for serving fetch requests.
> > > > > > > > >
> > > > > > > > > Right, remote.log.manager.thread.pool is mainly used for
> > > > copy/cleanup
> > > > > > > > > activities. Fetch path always goes through
> > > > remote.log.reader.threads.
> > > > > > > > >
> > > > > > > > > 5103.4 remote.log.manager.task.interval.ms: Is that the
> amount
> > > > of
> > > > > > time
> > > > > > > > to
> > > > > > > > > back off when there is no work to do? If so, perhaps it
> can be
> > > > > > renamed as
> > > > > > > > > backoff.ms.
> > > > > > > > >
> > > > > > > > > This is the delay interval for each iteration. It may be
> > > renamed
> > > > to
> > > > > > > > > remote.log.manager.task.delay.ms
> > > > > > > > >
> > > > > > > > > 5103.5 Are rlm_process_interval_ms and
> rlm_retry_interval_ms
> > > > > > configs? If
> > > > > > > > > so, they need to be listed in this section.
> > > > > > > > >
> > > > > > > > > remote.log.manager.task.interval.ms is the process
> internal,
> > > > retry
> > > > > > > > > interval is missing in the configs, which will be updated
> in
> > > the
> > > > KIP.
> > > > > > > > >
> > > > > > > > > 5104. "RLM maintains a bounded cache(possibly LRU) of the
> index
> > > > > > files of
> > > > > > > > > remote log segments to avoid multiple index fetches from
> the
> > > > remote
> > > > > > > > > storage." Is the RLM in memory or on disk? If on disk,
> where is
> > > > it
> > > > > > > > stored?
> > > > > > > > > Do we need a configuration to bound the size?
> > > > > > > > >
> > > > > > > > > It is stored on disk. They are stored in a directory
> > > > > > > > > `remote-log-index-cache` under log dir. We plan to have a
> > > config
> > > > for
> > > > > > > > > that instead of default. We will have a configuration for
> that.
> > > > > > > > >
> > > > > > > > > 5105. The KIP uses local-log-start-offset and Earliest
> Local
> > > > Offset
> > > > > > in
> > > > > > > > > different places. It would be useful to standardize the
> > > > terminology.
> > > > > > > > >
> > > > > > > > > Sure.
> > > > > > > > >
> > > > > > > > > 5106. The section on "In BuildingRemoteLogAux state". It
> listed
> > > > two
> > > > > > > > options
> > > > > > > > > without saying which option is chosen.
> > > > > > > > > We already mentioned in the KIP that we chose option-2.
> > > > > > > > >
> > > > > > > > > 5107. Follower to leader transition: It has step 2, but not
> > > step
> > > > 1.
> > > > > > > > > Step-1 is there but it is not explicitly highlighted. It is
> > > > previous
> > > > > > > > > table to step-2.
> > > > > > > > >
> > > > > > > > > 5108. If a consumer fetches from the remote data and the
> remote
> > > > > > storage
> > > > > > > > is
> > > > > > > > > not available, what error code is used in the fetch
> response?
> > > > > > > > >
> > > > > > > > > Good point. We have not yet defined the error for this
> case. We
> > > > need
> > > > > > > > > to define an error message and send the same in fetch
> response.
> > > > > > > > >
> > > > > > > > > 5109. "ListOffsets: For timestamps >= 0, it returns the
> first
> > > > message
> > > > > > > > > offset whose timestamp is >= to the given timestamp in the
> > > > request.
> > > > > > That
> > > > > > > > > means it checks in remote log time indexes first, after
> which
> > > > local
> > > > > > log
> > > > > > > > > time indexes are checked." Could you document which method
> in
> > > > RLMM is
> > > > > > > > used
> > > > > > > > > for this?
> > > > > > > > >
> > > > > > > > > Okay.
> > > > > > > > >
> > > > > > > > > 5110. Stopreplica: "it sets all the remote log segment
> metadata
> > > > of
> > > > > > that
> > > > > > > > > partition with a delete marker and publishes them to RLMM."
> > > This
> > > > > > seems
> > > > > > > > > outdated given the new topic deletion logic.
> > > > > > > > >
> > > > > > > > > Will update with KIP-516 related points.
> > > > > > > > >
> > > > > > > > > 5111. "RLM follower fetches the earliest offset for the
> > > earliest
> > > > > > leader
> > > > > > > > > epoch by calling RLMM.earliestLogOffset(TopicPartition
> > > > > > topicPartition,
> > > > > > > > int
> > > > > > > > > leaderEpoch) and updates that as the log start offset." Do
> we
> > > > need
> > > > > > that
> > > > > > > > > since replication propagates logStartOffset already?
> > > > > > > > >
> > > > > > > > > Good point. Right, existing replication protocol takes
> care of
> > > > > > > > > updating the followers’s log start offset received from the
> > > > leader.
> > > > > > > > >
> > > > > > > > > 5112. Is the default maxWaitMs of 500ms enough for fetching
> > > from
> > > > > > remote
> > > > > > > > > storage?
> > > > > > > > >
> > > > > > > > > Remote reads may fail within the current default wait
> time, but
> > > > > > > > > subsequent fetches would be able to serve as that data is
> > > stored
> > > > in
> > > > > > > > > the local cache. This cache is currently implemented in
> RSMs.
> > > > But we
> > > > > > > > > plan to pull this into the remote log messaging layer in
> > > future.
> > > > > > > > >
> > > > > > > > > 5113. "Committed offsets can be stored in a local file to
> avoid
> > > > > > reading
> > > > > > > > the
> > > > > > > > > messages again when a broker is restarted." Could you
> describe
> > > > the
> > > > > > format
> > > > > > > > > and the location of the file? Also, could the same message
> be
> > > > > > processed
> > > > > > > > by
> > > > > > > > > RLMM again after broker restart? If so, how do we handle
> that?
> > > > > > > > >
> > > > > > > > > Sure, we will update in the KIP.
> > > > > > > > >
> > > > > > > > > 5114. Message format
> > > > > > > > > 5114.1 There are two records named
> > > RemoteLogSegmentMetadataRecord
> > > > > > with
> > > > > > > > > apiKey 0 and 1.
> > > > > > > > >
> > > > > > > > > Nice catch, that was a typo. Fixed in the wiki.
> > > > > > > > >
> > > > > > > > > 5114.2 RemoteLogSegmentMetadataRecord: Could we document
> > > whether
> > > > > > > > endOffset
> > > > > > > > > is inclusive/exclusive?
> > > > > > > > > It is inclusive, will update.
> > > > > > > > >
> > > > > > > > > 5114.3 RemoteLogSegmentMetadataRecord: Could you explain
> > > > LeaderEpoch
> > > > > > a
> > > > > > > > bit
> > > > > > > > > more? Is that the epoch of the leader when it copies the
> > > segment
> > > > to
> > > > > > > > remote
> > > > > > > > > storage? Also, how will this field be used?
> > > > > > > > >
> > > > > > > > > Right, this is the leader epoch of the broker which copied
> this
> > > > > > > > > segment. This is helpful in reason about which broker
> copied
> > > the
> > > > > > > > > segment to remote storage.
> > > > > > > > >
> > > > > > > > > 5114.4 EventTimestamp: Could you explain this a bit more?
> Each
> > > > > > record in
> > > > > > > > > Kafka already has a timestamp field. Could we just use
> that?
> > > > > > > > >
> > > > > > > > > This is the  timestamp at which  the respective event
> occurred.
> > > > Added
> > > > > > > > > this  to RemoteLogSegmentMetadata as RLMM can be  any other
> > > > > > > > > implementation. We thought about that but it looked
> cleaner to
> > > > use at
> > > > > > > > > the message structure level instead of getting that from
> the
> > > > consumer
> > > > > > > > > record and using that to build the respective event.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > 5114.5 SegmentSizeInBytes: Could this just be int32?
> > > > > > > > >
> > > > > > > > > Right, it looks like config allows only int value >= 14.
> > > > > > > > >
> > > > > > > > > 5115. RemoteLogCleaner(RLC): This could be confused with
> the
> > > log
> > > > > > cleaner
> > > > > > > > > for compaction. Perhaps it can be renamed to sth like
> > > > > > > > > RemotePartitionRemover.
> > > > > > > > >
> > > > > > > > > I am fine with RemotePartitionRemover or
> > > > RemoteLogDeletionManager(we
> > > > > > > > > have other manager classes like RLM, RLMM).
> > > > > > > > >
> > > > > > > > > 5116. "RLC receives the delete_partition_marked and
> processes
> > > it
> > > > if
> > > > > > it is
> > > > > > > > > not yet processed earlier." How does it know whether
> > > > > > > > > delete_partition_marked has been processed earlier?
> > > > > > > > >
> > > > > > > > > This is to handle duplicate delete_partition_marked
> events. RLC
> > > > > > > > > internally maintains a state for the delete_partition
> events
> > > and
> > > > if
> > > > > > it
> > > > > > > > > already has an existing event then it ignores if it is
> already
> > > > being
> > > > > > > > > processed.
> > > > > > > > >
> > > > > > > > > 5117. Should we add a new MessageFormatter to read the tier
> > > > metadata
> > > > > > > > topic?
> > > > > > > > >
> > > > > > > > > Right, this is in plan but did not mention it in the KIP.
> This
> > > > will
> > > > > > be
> > > > > > > > > useful for debugging purposes too.
> > > > > > > > >
> > > > > > > > > 5118. "Maximum remote log reader thread pool task queue
> size.
> > > If
> > > > the
> > > > > > task
> > > > > > > > > queue is full, broker will stop reading remote log
> segments."
> > > > What
> > > > > > do we
> > > > > > > > > return to the fetch request in this case?
> > > > > > > > >
> > > > > > > > > We return an error response for that partition.
> > > > > > > > >
> > > > > > > > > 5119. It would be useful to list all things not supported
> in
> > > the
> > > > > > first
> > > > > > > > > version in a Future work or Limitations section. For
> example,
> > > > > > compacted
> > > > > > > > > topic, JBOD, changing remote.log.storage.enable from true
> to
> > > > false,
> > > > > > etc.
> > > > > > > > >
> > > > > > > > > We already have a non-goals section which is filled with
> some
> > > of
> > > > > > these
> > > > > > > > > details. Do we need another limitations section?
> > > > > > > > >
> > > > > > > > > Thanks,
> > > > > > > > > Satish.
> > > > > > > > >
> > > > > > > > > On Wed, Nov 4, 2020 at 11:27 PM Jun Rao <ju...@confluent.io>
> > > > wrote:
> > > > > > > > > >
> > > > > > > > > > Hi, Satish,
> > > > > > > > > >
> > > > > > > > > > Thanks for the updated KIP. A few more comments below.
> > > > > > > > > >
> > > > > > > > > > 605.2 "Build the local leader epoch cache by cutting the
> > > leader
> > > > > > epoch
> > > > > > > > > > sequence received from remote storage to [LSO, ELO]." I
> > > > mentioned
> > > > > > an
> > > > > > > > issue
> > > > > > > > > > earlier. Suppose the leader's local start offset is 100.
> The
> > > > > > follower
> > > > > > > > finds
> > > > > > > > > > a remote segment covering offset range [80, 120). The
> > > > producerState
> > > > > > > > with
> > > > > > > > > > this remote segment is up to offset 120. To trim the
> > > > producerState
> > > > > > to
> > > > > > > > > > offset 100 requires more work since one needs to
> download the
> > > > > > previous
> > > > > > > > > > producerState up to offset 80 and then replay the
> messages
> > > > from 80
> > > > > > to
> > > > > > > > 100.
> > > > > > > > > > It seems that it's simpler in this case for the follower
> just
> > > > to
> > > > > > take
> > > > > > > > the
> > > > > > > > > > remote segment as it is and start fetching from offset
> 120.
> > > > > > > > > >
> > > > > > > > > > 5016. Just to echo what Kowshik was saying. It seems that
> > > > > > > > > > RLMM.onPartitionLeadershipChanges() is only called on the
> > > > replicas
> > > > > > for
> > > > > > > > a
> > > > > > > > > > partition, not on the replicas for the
> > > > > > __remote_log_segment_metadata
> > > > > > > > > > partition. It's not clear how the leader of
> > > > > > > > __remote_log_segment_metadata
> > > > > > > > > > obtains the metadata for remote segments for deletion.
> > > > > > > > > >
> > > > > > > > > > 5100. KIP-516 has been accepted and is being implemented
> now.
> > > > > > Could you
> > > > > > > > > > update the KIP based on topicID?
> > > > > > > > > >
> > > > > > > > > > 5101. RLMM: It would be useful to clarify how the
> following
> > > two
> > > > > > APIs
> > > > > > > > are
> > > > > > > > > > used. According to the wiki, the former is used for topic
> > > > deletion
> > > > > > and
> > > > > > > > the
> > > > > > > > > > latter is used for retention. It seems that retention
> should
> > > > use
> > > > > > the
> > > > > > > > former
> > > > > > > > > > since remote segments without a matching epoch in the
> leader
> > > > > > > > (potentially
> > > > > > > > > > due to unclean leader election) also need to be garbage
> > > > collected.
> > > > > > The
> > > > > > > > > > latter seems to be used for the new leader to determine
> the
> > > > last
> > > > > > tiered
> > > > > > > > > > segment.
> > > > > > > > > >     default Iterator<RemoteLogSegmentMetadata>
> > > > > > > > > > listRemoteLogSegments(TopicPartition topicPartition)
> > > > > > > > > >     Iterator<RemoteLogSegmentMetadata>
> > > > > > > > listRemoteLogSegments(TopicPartition
> > > > > > > > > > topicPartition, long leaderEpoch);
> > > > > > > > > >
> > > > > > > > > > 5102. RSM:
> > > > > > > > > > 5102.1 For methods like fetchLogSegmentData(), it seems
> that
> > > > they
> > > > > > can
> > > > > > > > > > use RemoteLogSegmentId instead of
> RemoteLogSegmentMetadata.
> > > > > > > > > > 5102.2 In fetchLogSegmentData(), should we use long
> instead
> > > of
> > > > > > Long?
> > > > > > > > > > 5102.3 Why only some of the methods have default
> > > > implementation and
> > > > > > > > others
> > > > > > > > > > don't?
> > > > > > > > > > 5102.4. Could we define RemoteLogSegmentMetadataUpdate
> > > > > > > > > > and DeletePartitionUpdate?
> > > > > > > > > > 5102.5 LogSegmentData: It seems that it's easier to pass
> > > > > > > > > > in leaderEpochIndex as a ByteBuffer or byte array than a
> file
> > > > > > since it
> > > > > > > > will
> > > > > > > > > > be generated in memory.
> > > > > > > > > > 5102.6 RemoteLogSegmentMetadata: It seems that it needs
> both
> > > > > > > > baseOffset and
> > > > > > > > > > startOffset. For example, deleteRecords() could move the
> > > > > > startOffset
> > > > > > > > to the
> > > > > > > > > > middle of a segment. If we copy the full segment to
> remote
> > > > > > storage, the
> > > > > > > > > > baseOffset and the startOffset will be different.
> > > > > > > > > > 5102.7 Could we define all the public methods for
> > > > > > > > RemoteLogSegmentMetadata
> > > > > > > > > > and LogSegmentData?
> > > > > > > > > > 5102.8 Could we document whether endOffset in
> > > > > > RemoteLogSegmentMetadata
> > > > > > > > is
> > > > > > > > > > inclusive/exclusive?
> > > > > > > > > >
> > > > > > > > > > 5103. configs:
> > > > > > > > > > 5103.1 Could we define the default value of non-required
> > > > configs
> > > > > > (e.g
> > > > > > > > the
> > > > > > > > > > size of new thread pools)?
> > > > > > > > > > 5103.2 It seems that local.log.retention.ms should
> default
> > > to
> > > > > > > > retention.ms,
> > > > > > > > > > instead of remote.log.retention.minutes. Similarly, it
> seems
> > > > > > > > > > that local.log.retention.bytes should default to
> > > segment.bytes.
> > > > > > > > > > 5103.3 remote.log.manager.thread.pool.size: The
> description
> > > > says
> > > > > > "used
> > > > > > > > in
> > > > > > > > > > scheduling tasks to copy segments, fetch remote log
> indexes
> > > and
> > > > > > clean
> > > > > > > > up
> > > > > > > > > > remote log segments". However, there is a separate
> > > > > > > > > > config remote.log.reader.threads for fetching remote
> data.
> > > It's
> > > > > > weird
> > > > > > > > to
> > > > > > > > > > fetch remote index and log in different thread pools
> since
> > > > both are
> > > > > > > > used
> > > > > > > > > > for serving fetch requests.
> > > > > > > > > > 5103.4 remote.log.manager.task.interval.ms: Is that the
> > > > amount of
> > > > > > > > time to
> > > > > > > > > > back off when there is no work to do? If so, perhaps it
> can
> > > be
> > > > > > renamed
> > > > > > > > as
> > > > > > > > > > backoff.ms.
> > > > > > > > > > 5103.5 Are rlm_process_interval_ms and
> rlm_retry_interval_ms
> > > > > > configs?
> > > > > > > > If
> > > > > > > > > > so, they need to be listed in this section.
> > > > > > > > > >
> > > > > > > > > > 5104. "RLM maintains a bounded cache(possibly LRU) of the
> > > index
> > > > > > files
> > > > > > > > of
> > > > > > > > > > remote log segments to avoid multiple index fetches from
> the
> > > > remote
> > > > > > > > > > storage." Is the RLM in memory or on disk? If on disk,
> where
> > > > is it
> > > > > > > > stored?
> > > > > > > > > > Do we need a configuration to bound the size?
> > > > > > > > > >
> > > > > > > > > > 5105. The KIP uses local-log-start-offset and Earliest
> Local
> > > > > > Offset in
> > > > > > > > > > different places. It would be useful to standardize the
> > > > > > terminology.
> > > > > > > > > >
> > > > > > > > > > 5106. The section on "In BuildingRemoteLogAux state". It
> > > > listed two
> > > > > > > > options
> > > > > > > > > > without saying which option is chosen.
> > > > > > > > > >
> > > > > > > > > > 5107. Follower to leader transition: It has step 2, but
> not
> > > > step 1.
> > > > > > > > > >
> > > > > > > > > > 5108. If a consumer fetches from the remote data and the
> > > remote
> > > > > > > > storage is
> > > > > > > > > > not available, what error code is used in the fetch
> response?
> > > > > > > > > >
> > > > > > > > > > 5109. "ListOffsets: For timestamps >= 0, it returns the
> first
> > > > > > message
> > > > > > > > > > offset whose timestamp is >= to the given timestamp in
> the
> > > > request.
> > > > > > > > That
> > > > > > > > > > means it checks in remote log time indexes first, after
> which
> > > > > > local log
> > > > > > > > > > time indexes are checked." Could you document which
> method in
> > > > RLMM
> > > > > > is
> > > > > > > > used
> > > > > > > > > > for this?
> > > > > > > > > >
> > > > > > > > > > 5110. Stopreplica: "it sets all the remote log segment
> > > > metadata of
> > > > > > that
> > > > > > > > > > partition with a delete marker and publishes them to
> RLMM."
> > > > This
> > > > > > seems
> > > > > > > > > > outdated given the new topic deletion logic.
> > > > > > > > > >
> > > > > > > > > > 5111. "RLM follower fetches the earliest offset for the
> > > > earliest
> > > > > > leader
> > > > > > > > > > epoch by calling RLMM.earliestLogOffset(TopicPartition
> > > > > > topicPartition,
> > > > > > > > int
> > > > > > > > > > leaderEpoch) and updates that as the log start offset."
> Do we
> > > > need
> > > > > > that
> > > > > > > > > > since replication propagates logStartOffset already?
> > > > > > > > > >
> > > > > > > > > > 5112. Is the default maxWaitMs of 500ms enough for
> fetching
> > > > from
> > > > > > remote
> > > > > > > > > > storage?
> > > > > > > > > >
> > > > > > > > > > 5113. "Committed offsets can be stored in a local file to
> > > avoid
> > > > > > > > reading the
> > > > > > > > > > messages again when a broker is restarted." Could you
> > > describe
> > > > the
> > > > > > > > format
> > > > > > > > > > and the location of the file? Also, could the same
> message be
> > > > > > > > processed by
> > > > > > > > > > RLMM again after broker restart? If so, how do we handle
> > > that?
> > > > > > > > > >
> > > > > > > > > > 5114. Message format
> > > > > > > > > > 5114.1 There are two records named
> > > > RemoteLogSegmentMetadataRecord
> > > > > > with
> > > > > > > > > > apiKey 0 and 1.
> > > > > > > > > > 5114.2 RemoteLogSegmentMetadataRecord: Could we document
> > > > whether
> > > > > > > > endOffset
> > > > > > > > > > is inclusive/exclusive?
> > > > > > > > > > 5114.3 RemoteLogSegmentMetadataRecord: Could you explain
> > > > > > LeaderEpoch a
> > > > > > > > bit
> > > > > > > > > > more? Is that the epoch of the leader when it copies the
> > > > segment to
> > > > > > > > remote
> > > > > > > > > > storage? Also, how will this field be used?
> > > > > > > > > > 5114.4 EventTimestamp: Could you explain this a bit more?
> > > Each
> > > > > > record
> > > > > > > > in
> > > > > > > > > > Kafka already has a timestamp field. Could we just use
> that?
> > > > > > > > > > 5114.5 SegmentSizeInBytes: Could this just be int32?
> > > > > > > > > >
> > > > > > > > > > 5115. RemoteLogCleaner(RLC): This could be confused with
> the
> > > > log
> > > > > > > > cleaner
> > > > > > > > > > for compaction. Perhaps it can be renamed to sth like
> > > > > > > > > > RemotePartitionRemover.
> > > > > > > > > >
> > > > > > > > > > 5116. "RLC receives the delete_partition_marked and
> processes
> > > > it
> > > > > > if it
> > > > > > > > is
> > > > > > > > > > not yet processed earlier." How does it know whether
> > > > > > > > > > delete_partition_marked has been processed earlier?
> > > > > > > > > >
> > > > > > > > > > 5117. Should we add a new MessageFormatter to read the
> tier
> > > > > > metadata
> > > > > > > > topic?
> > > > > > > > > >
> > > > > > > > > > 5118. "Maximum remote log reader thread pool task queue
> size.
> > > > If
> > > > > > the
> > > > > > > > task
> > > > > > > > > > queue is full, broker will stop reading remote log
> segments."
> > > > What
> > > > > > do
> > > > > > > > we
> > > > > > > > > > return to the fetch request in this case?
> > > > > > > > > >
> > > > > > > > > > 5119. It would be useful to list all things not
> supported in
> > > > the
> > > > > > first
> > > > > > > > > > version in a Future work or Limitations section. For
> example,
> > > > > > compacted
> > > > > > > > > > topic, JBOD, changing remote.log.storage.enable from
> true to
> > > > false,
> > > > > > > > etc.
> > > > > > > > > >
> > > > > > > > > > Thanks,
> > > > > > > > > >
> > > > > > > > > > Jun
> > > > > > > > > >
> > > > > > > > > > On Tue, Oct 27, 2020 at 5:57 PM Kowshik Prakasam <
> > > > > > > > kprakasam@confluent.io>
> > > > > > > > > > wrote:
> > > > > > > > > >
> > > > > > > > > > > Hi Satish,
> > > > > > > > > > >
> > > > > > > > > > > Thanks for the updates to the KIP. Here are my first
> batch
> > > of
> > > > > > > > > > > comments/suggestions on the latest version of the KIP.
> > > > > > > > > > >
> > > > > > > > > > > 5012. In the RemoteStorageManager interface, there is
> an
> > > API
> > > > > > defined
> > > > > > > > for
> > > > > > > > > > > each file type. For example, fetchOffsetIndex,
> > > > > > fetchTimestampIndex
> > > > > > > > etc. To
> > > > > > > > > > > avoid the duplication, I'd suggest we can instead have
> a
> > > > FileType
> > > > > > > > enum and
> > > > > > > > > > > a common get API based on the FileType.
> > > > > > > > > > >
> > > > > > > > > > > 5013. There are some references to the Google doc in
> the
> > > > KIP. I
> > > > > > > > wasn't sure
> > > > > > > > > > > if the Google doc is expected to be in sync with the
> > > > contents of
> > > > > > the
> > > > > > > > wiki.
> > > > > > > > > > > Going forward, it seems easier if just the KIP is
> > > maintained
> > > > as
> > > > > > the
> > > > > > > > source
> > > > > > > > > > > of truth. In this regard, could you please move all the
> > > > > > references
> > > > > > > > to the
> > > > > > > > > > > Google doc, maybe to a separate References section at
> the
> > > > bottom
> > > > > > of
> > > > > > > > the
> > > > > > > > > > > KIP?
> > > > > > > > > > >
> > > > > > > > > > > 5014. There are some TODO sections in the KIP. Would
> these
> > > be
> > > > > > filled
> > > > > > > > up in
> > > > > > > > > > > future iterations?
> > > > > > > > > > >
> > > > > > > > > > > 5015. Under "Topic deletion lifecycle", I'm trying to
> > > > understand
> > > > > > why
> > > > > > > > do we
> > > > > > > > > > > need delete_partition_marked as well as the
> > > > > > delete_partition_started
> > > > > > > > > > > messages. I couldn't spot a drawback if supposing we
> > > > simplified
> > > > > > the
> > > > > > > > design
> > > > > > > > > > > such that the controller would only write
> > > > > > delete_partition_started
> > > > > > > > message,
> > > > > > > > > > > and RemoteLogCleaner (RLC) instance picks it up for
> > > > processing.
> > > > > > What
> > > > > > > > am I
> > > > > > > > > > > missing?
> > > > > > > > > > >
> > > > > > > > > > > 5016. Under "Topic deletion lifecycle", step (4) is
> > > > mentioned as
> > > > > > > > "RLC gets
> > > > > > > > > > > all the remote log segments for the partition and each
> of
> > > > these
> > > > > > > > remote log
> > > > > > > > > > > segments is deleted with the next steps.". Since the
> RLC
> > > > instance
> > > > > > > > runs on
> > > > > > > > > > > each tier topic partition leader, how does the RLC
> then get
> > > > the
> > > > > > list
> > > > > > > > of
> > > > > > > > > > > remote log segments to be deleted? It will be useful
> to add
> > > > that
> > > > > > > > detail to
> > > > > > > > > > > the KIP.
> > > > > > > > > > >
> > > > > > > > > > > 5017. Under "Public Interfaces -> Configs", there is a
> line
> > > > > > > > mentioning "We
> > > > > > > > > > > will support flipping remote.log.storage.enable in next
> > > > > > versions."
> > > > > > > > It will
> > > > > > > > > > > be useful to mention this in the "Future Work" section
> of
> > > > the KIP
> > > > > > > > too.
> > > > > > > > > > >
> > > > > > > > > > > 5018. The KIP introduces a number of configuration
> > > > parameters. It
> > > > > > > > will be
> > > > > > > > > > > useful to mention in the KIP if the user should assume
> > > these
> > > > as
> > > > > > > > static
> > > > > > > > > > > configuration in the server.properties file, or dynamic
> > > > > > > > configuration which
> > > > > > > > > > > can be modified without restarting the broker.
> > > > > > > > > > >
> > > > > > > > > > > 5019.  Maybe this is planned as a future update to the
> KIP,
> > > > but I
> > > > > > > > thought
> > > > > > > > > > > I'd mention it here. Could you please add details to
> the
> > > KIP
> > > > on
> > > > > > why
> > > > > > > > RocksDB
> > > > > > > > > > > was chosen as the default cache implementation of
> RLMM, and
> > > > how
> > > > > > it
> > > > > > > > is going
> > > > > > > > > > > to be used? Were alternatives compared/considered? For
> > > > example,
> > > > > > it
> > > > > > > > would be
> > > > > > > > > > > useful to explain/evaluate the following: 1)
> debuggability
> > > > of the
> > > > > > > > RocksDB
> > > > > > > > > > > JNI interface, 2) performance, 3) portability across
> > > > platforms
> > > > > > and 4)
> > > > > > > > > > > interface parity of RocksDB’s JNI api with it's
> underlying
> > > > C/C++
> > > > > > api.
> > > > > > > > > > >
> > > > > > > > > > > 5020. Following up on (5019), for the RocksDB cache, it
> > > will
> > > > be
> > > > > > > > useful to
> > > > > > > > > > > explain the relationship/mapping between the following
> in
> > > the
> > > > > > KIP:
> > > > > > > > 1) # of
> > > > > > > > > > > tiered partitions, 2) # of partitions of metadata topic
> > > > > > > > > > > __remote_log_metadata and 3) # of RocksDB instances.
> i.e.
> > > is
> > > > the
> > > > > > > > plan to
> > > > > > > > > > > have a RocksDB instance per tiered partition, or per
> > > metadata
> > > > > > topic
> > > > > > > > > > > partition, or just 1 for per broker?
> > > > > > > > > > >
> > > > > > > > > > > 5021. I was looking at the implementation prototype (PR
> > > link:
> > > > > > > > > > > https://github.com/apache/kafka/pull/7561). It seems
> that
> > > a
> > > > > > boolean
> > > > > > > > > > > attribute is being introduced into the Log layer to
> check
> > > if
> > > > > > remote
> > > > > > > > log
> > > > > > > > > > > capability is enabled. While the boolean footprint is
> small
> > > > at
> > > > > > the
> > > > > > > > moment,
> > > > > > > > > > > this can easily grow in the future and become harder to
> > > > > > > > > > > test/maintain, considering that the Log layer is
> already
> > > > pretty
> > > > > > > > complex. We
> > > > > > > > > > > should start thinking about how to manage such changes
> to
> > > > the Log
> > > > > > > > layer
> > > > > > > > > > > (for the purpose of improved testability, better
> separation
> > > > of
> > > > > > > > concerns and
> > > > > > > > > > > readability). One proposal I have is to take a step
> back
> > > and
> > > > > > define a
> > > > > > > > > > > higher level Log interface. Then, the Broker code can
> be
> > > > changed
> > > > > > to
> > > > > > > > use
> > > > > > > > > > > this interface. It can be changed such that only a
> handle
> > > to
> > > > the
> > > > > > > > interface
> > > > > > > > > > > is exposed to other components (such as LogCleaner,
> > > > > > ReplicaManager
> > > > > > > > etc.)
> > > > > > > > > > > and not the underlying Log object. This approach keeps
> the
> > > > user
> > > > > > of
> > > > > > > > the Log
> > > > > > > > > > > layer agnostic of the whereabouts of the data.
> Underneath
> > > the
> > > > > > > > interface,
> > > > > > > > > > > the implementing classes can completely separate local
> log
> > > > > > > > capabilities
> > > > > > > > > > > from the remote log. For example, the Log class can be
> > > > > > simplified to
> > > > > > > > only
> > > > > > > > > > > manage logic surrounding local log segments and
> metadata.
> > > > > > > > Additionally, a
> > > > > > > > > > > wrapper class can be provided (implementing the higher
> > > level
> > > > Log
> > > > > > > > interface)
> > > > > > > > > > > which will contain any/all logic surrounding tiered
> data.
> > > The
> > > > > > wrapper
> > > > > > > > > > > class will wrap around an instance of the Log class
> > > > delegating
> > > > > > the
> > > > > > > > local
> > > > > > > > > > > log logic to it. Finally, a handle to the wrapper
> class can
> > > > be
> > > > > > > > exposed to
> > > > > > > > > > > the other components wherever they need a handle to the
> > > > higher
> > > > > > level
> > > > > > > > Log
> > > > > > > > > > > interface.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > Cheers,
> > > > > > > > > > > Kowshik
> > > > > > > > > > >
> > > > > > > > > > > On Mon, Oct 26, 2020 at 9:52 PM Satish Duggana <
> > > > > > > > satish.duggana@gmail.com>
> > > > > > > > > > > wrote:
> > > > > > > > > > >
> > > > > > > > > > > > Hi,
> > > > > > > > > > > > KIP is updated with 1) topic deletion lifecycle and
> its
> > > > related
> > > > > > > > items
> > > > > > > > > > > > 2) Protocol changes(mainly related to ListOffsets)
> and
> > > > other
> > > > > > minor
> > > > > > > > > > > > changes.
> > > > > > > > > > > > Please go through them and let us know your comments.
> > > > > > > > > > > >
> > > > > > > > > > > > Thanks,
> > > > > > > > > > > > Satish.
> > > > > > > > > > > >
> > > > > > > > > > > > On Mon, Sep 28, 2020 at 9:10 PM Satish Duggana <
> > > > > > > > satish.duggana@gmail.com
> > > > > > > > > > > >
> > > > > > > > > > > > wrote:
> > > > > > > > > > > > >
> > > > > > > > > > > > > Hi Dhruvil,
> > > > > > > > > > > > > Thanks for looking into the KIP and sending your
> > > > comments.
> > > > > > Sorry
> > > > > > > > for
> > > > > > > > > > > > > the late reply, missed it in the mail thread.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 1. Could you describe how retention would work with
> > > this
> > > > KIP
> > > > > > and
> > > > > > > > which
> > > > > > > > > > > > > threads are responsible for driving this work? I
> > > believe
> > > > > > there
> > > > > > > > are 3
> > > > > > > > > > > > kinds
> > > > > > > > > > > > > of retention processes we are looking at:
> > > > > > > > > > > > >   (a) Regular retention for data in tiered storage
> as
> > > per
> > > > > > > > configured `
> > > > > > > > > > > > > retention.ms` / `retention.bytes`.
> > > > > > > > > > > > >   (b) Local retention for data in local storage as
> per
> > > > > > > > configured `
> > > > > > > > > > > > > local.log.retention.ms` /
> `local.log.retention.bytes`
> > > > > > > > > > > > >   (c) Possibly regular retention for data in local
> > > > storage,
> > > > > > if
> > > > > > > > the
> > > > > > > > > > > > tiering
> > > > > > > > > > > > > task is lagging or for data that is below the log
> start
> > > > > > offset.
> > > > > > > > > > > > >
> > > > > > > > > > > > > Local log retention is done by the existing log
> cleanup
> > > > > > tasks.
> > > > > > > > These
> > > > > > > > > > > > > are not done for segments that are not yet copied
> to
> > > > remote
> > > > > > > > storage.
> > > > > > > > > > > > > Remote log cleanup is done by the leader
> partition’s
> > > > RLMTask.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 2. When does a segment become eligible to be
> tiered? Is
> > > > it as
> > > > > > > > soon as
> > > > > > > > > > > the
> > > > > > > > > > > > > segment is rolled and the end offset is less than
> the
> > > > last
> > > > > > stable
> > > > > > > > > > > offset
> > > > > > > > > > > > as
> > > > > > > > > > > > > mentioned in the KIP? I wonder if we need to
> consider
> > > > other
> > > > > > > > parameters
> > > > > > > > > > > > too,
> > > > > > > > > > > > > like the highwatermark so that we are guaranteed
> that
> > > > what
> > > > > > we are
> > > > > > > > > > > tiering
> > > > > > > > > > > > > has been committed to the log and accepted by the
> ISR.
> > > > > > > > > > > > >
> > > > > > > > > > > > > AFAIK, last stable offset is always <=
> highwatermark.
> > > > This
> > > > > > will
> > > > > > > > make
> > > > > > > > > > > > > sure we are always tiering the message segments
> which
> > > > have
> > > > > > been
> > > > > > > > > > > > > accepted by ISR and transactionally completed.
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > 3. The section on "Follower Fetch Scenarios" is
> useful
> > > > but
> > > > > > is a
> > > > > > > > bit
> > > > > > > > > > > > > difficult to parse at the moment. It would be
> useful to
> > > > > > > > summarize the
> > > > > > > > > > > > > changes we need in the ReplicaFetcher.
> > > > > > > > > > > > >
> > > > > > > > > > > > > It may become difficult for users to read/follow
> if we
> > > > add
> > > > > > code
> > > > > > > > changes
> > > > > > > > > > > > here.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 4. Related to the above, it's a bit unclear how we
> are
> > > > > > planning
> > > > > > > > on
> > > > > > > > > > > > > restoring the producer state for a new replica.
> Could
> > > you
> > > > > > expand
> > > > > > > > on
> > > > > > > > > > > that?
> > > > > > > > > > > > >
> > > > > > > > > > > > > It is mentioned in the KIP
> BuildingRemoteLogAuxState is
> > > > > > > > introduced to
> > > > > > > > > > > > > build the state like leader epoch sequence and
> producer
> > > > > > snapshots
> > > > > > > > > > > > > before it starts fetching the data from the
> leader. We
> > > > will
> > > > > > make
> > > > > > > > it
> > > > > > > > > > > > > clear in the KIP.
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5. Similarly, it would be worth summarizing the
> > > behavior
> > > > on
> > > > > > > > unclean
> > > > > > > > > > > > leader
> > > > > > > > > > > > > election. There are several scenarios to consider
> here:
> > > > data
> > > > > > > > loss from
> > > > > > > > > > > > > local log, data loss from remote log, data loss
> from
> > > > metadata
> > > > > > > > topic,
> > > > > > > > > > > etc.
> > > > > > > > > > > > > It's worth describing these in detail.
> > > > > > > > > > > > >
> > > > > > > > > > > > > We mentioned the cases about unclean leader
> election in
> > > > the
> > > > > > > > follower
> > > > > > > > > > > > > fetch scenarios.
> > > > > > > > > > > > > If there are errors while fetching data from remote
> > > > store or
> > > > > > > > metadata
> > > > > > > > > > > > > store, it will work the same way as it works with
> local
> > > > log.
> > > > > > It
> > > > > > > > > > > > > returns the error back to the caller. Please let us
> > > know
> > > > if
> > > > > > I am
> > > > > > > > > > > > > missing your point here.
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > 7. For a READ_COMMITTED FetchRequest, how do we
> > > retrieve
> > > > and
> > > > > > > > return the
> > > > > > > > > > > > > aborted transaction metadata?
> > > > > > > > > > > > >
> > > > > > > > > > > > > When a fetch for a remote log is accessed, we will
> > > fetch
> > > > > > aborted
> > > > > > > > > > > > > transactions along with the segment if it is not
> found
> > > > in the
> > > > > > > > local
> > > > > > > > > > > > > index cache. This includes the case of transaction
> > > index
> > > > not
> > > > > > > > existing
> > > > > > > > > > > > > in the remote log segment. That means, the cache
> entry
> > > > can be
> > > > > > > > empty or
> > > > > > > > > > > > > have a list of aborted transactions.
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > 8. The `LogSegmentData` class assumes that we have
> a
> > > log
> > > > > > segment,
> > > > > > > > > > > offset
> > > > > > > > > > > > > index, time index, transaction index, producer
> snapshot
> > > > and
> > > > > > > > leader
> > > > > > > > > > > epoch
> > > > > > > > > > > > > index. How do we deal with cases where we do not
> have
> > > > one or
> > > > > > > > more of
> > > > > > > > > > > > these?
> > > > > > > > > > > > > For example, we may not have a transaction index or
> > > > producer
> > > > > > > > snapshot
> > > > > > > > > > > > for a
> > > > > > > > > > > > > particular segment. The former is optional, and the
> > > > latter is
> > > > > > > > only kept
> > > > > > > > > > > > for
> > > > > > > > > > > > > up to the 3 latest segments.
> > > > > > > > > > > > >
> > > > > > > > > > > > > This is a good point,  we discussed this in the
> last
> > > > meeting.
> > > > > > > > > > > > > Transaction index is optional and we will copy them
> > > only
> > > > if
> > > > > > it
> > > > > > > > exists.
> > > > > > > > > > > > > We want to keep all the producer snapshots at each
> log
> > > > > > segment
> > > > > > > > rolling
> > > > > > > > > > > > > and they can be removed if the log copying is
> > > successful
> > > > and
> > > > > > it
> > > > > > > > still
> > > > > > > > > > > > > maintains the existing latest 3 segments, We only
> > > delete
> > > > the
> > > > > > > > producer
> > > > > > > > > > > > > snapshots which have been copied to remote log
> segments
> > > > on
> > > > > > > > leader.
> > > > > > > > > > > > > Follower will keep the log segments beyond the
> segments
> > > > which
> > > > > > > > have not
> > > > > > > > > > > > > been copied to remote storage. We will update the
> KIP
> > > > with
> > > > > > these
> > > > > > > > > > > > > details.
> > > > > > > > > > > > >
> > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > Satish.
> > > > > > > > > > > > >
> > > > > > > > > > > > > On Thu, Sep 17, 2020 at 1:47 AM Dhruvil Shah <
> > > > > > > > dhruvil@confluent.io>
> > > > > > > > > > > > wrote:
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Hi Satish, Harsha,
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Thanks for the KIP. Few questions below:
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 1. Could you describe how retention would work
> with
> > > > this
> > > > > > KIP
> > > > > > > > and
> > > > > > > > > > > which
> > > > > > > > > > > > > > threads are responsible for driving this work? I
> > > > believe
> > > > > > there
> > > > > > > > are 3
> > > > > > > > > > > > kinds
> > > > > > > > > > > > > > of retention processes we are looking at:
> > > > > > > > > > > > > >   (a) Regular retention for data in tiered
> storage as
> > > > per
> > > > > > > > configured
> > > > > > > > > > > `
> > > > > > > > > > > > > > retention.ms` / `retention.bytes`.
> > > > > > > > > > > > > >   (b) Local retention for data in local storage
> as
> > > per
> > > > > > > > configured `
> > > > > > > > > > > > > > local.log.retention.ms` /
> > > `local.log.retention.bytes`
> > > > > > > > > > > > > >   (c) Possibly regular retention for data in
> local
> > > > > > storage, if
> > > > > > > > the
> > > > > > > > > > > > tiering
> > > > > > > > > > > > > > task is lagging or for data that is below the log
> > > start
> > > > > > offset.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 2. When does a segment become eligible to be
> tiered?
> > > > Is it
> > > > > > as
> > > > > > > > soon as
> > > > > > > > > > > > the
> > > > > > > > > > > > > > segment is rolled and the end offset is less
> than the
> > > > last
> > > > > > > > stable
> > > > > > > > > > > > offset as
> > > > > > > > > > > > > > mentioned in the KIP? I wonder if we need to
> consider
> > > > other
> > > > > > > > > > > parameters
> > > > > > > > > > > > too,
> > > > > > > > > > > > > > like the highwatermark so that we are guaranteed
> that
> > > > what
> > > > > > we
> > > > > > > > are
> > > > > > > > > > > > tiering
> > > > > > > > > > > > > > has been committed to the log and accepted by the
> > > ISR.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 3. The section on "Follower Fetch Scenarios" is
> > > useful
> > > > but
> > > > > > is
> > > > > > > > a bit
> > > > > > > > > > > > > > difficult to parse at the moment. It would be
> useful
> > > to
> > > > > > > > summarize the
> > > > > > > > > > > > > > changes we need in the ReplicaFetcher.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 4. Related to the above, it's a bit unclear how
> we
> > > are
> > > > > > > > planning on
> > > > > > > > > > > > > > restoring the producer state for a new replica.
> Could
> > > > you
> > > > > > > > expand on
> > > > > > > > > > > > that?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 5. Similarly, it would be worth summarizing the
> > > > behavior on
> > > > > > > > unclean
> > > > > > > > > > > > leader
> > > > > > > > > > > > > > election. There are several scenarios to consider
> > > here:
> > > > > > data
> > > > > > > > loss
> > > > > > > > > > > from
> > > > > > > > > > > > > > local log, data loss from remote log, data loss
> from
> > > > > > metadata
> > > > > > > > topic,
> > > > > > > > > > > > etc.
> > > > > > > > > > > > > > It's worth describing these in detail.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 6. It would be useful to add details about how we
> > > plan
> > > > on
> > > > > > using
> > > > > > > > > > > > RocksDB in
> > > > > > > > > > > > > > the default implementation of
> > > > `RemoteLogMetadataManager`.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 7. For a READ_COMMITTED FetchRequest, how do we
> > > > retrieve
> > > > > > and
> > > > > > > > return
> > > > > > > > > > > the
> > > > > > > > > > > > > > aborted transaction metadata?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 8. The `LogSegmentData` class assumes that we
> have a
> > > > log
> > > > > > > > segment,
> > > > > > > > > > > > offset
> > > > > > > > > > > > > > index, time index, transaction index, producer
> > > > snapshot and
> > > > > > > > leader
> > > > > > > > > > > > epoch
> > > > > > > > > > > > > > index. How do we deal with cases where we do not
> have
> > > > one
> > > > > > or
> > > > > > > > more of
> > > > > > > > > > > > these?
> > > > > > > > > > > > > > For example, we may not have a transaction index
> or
> > > > > > producer
> > > > > > > > snapshot
> > > > > > > > > > > > for a
> > > > > > > > > > > > > > particular segment. The former is optional, and
> the
> > > > latter
> > > > > > is
> > > > > > > > only
> > > > > > > > > > > > kept for
> > > > > > > > > > > > > > up to the 3 latest segments.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > Dhruvil
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > On Mon, Sep 7, 2020 at 6:54 PM Harsha Ch <
> > > > > > harsha.ch@gmail.com>
> > > > > > > > > > > wrote:
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Hi All,
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > We are all working through the last meeting
> > > feedback.
> > > > > > I'll
> > > > > > > > cancel
> > > > > > > > > > > the
> > > > > > > > > > > > > > > tomorrow 's meeting and we can meanwhile
> continue
> > > our
> > > > > > > > discussion in
> > > > > > > > > > > > mailing
> > > > > > > > > > > > > > > list. We can start the regular meeting from
> next
> > > week
> > > > > > > > onwards.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Harsha
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > On Fri, Sep 04, 2020 at 8:41 AM, Satish
> Duggana <
> > > > > > > > > > > > satish.duggana@gmail.com
> > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Hi Jun,
> > > > > > > > > > > > > > > > Thanks for your thorough review and comments.
> > > > Please
> > > > > > find
> > > > > > > > the
> > > > > > > > > > > > inline
> > > > > > > > > > > > > > > > replies below.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 600. The topic deletion logic needs more
> details.
> > > > > > > > > > > > > > > > 600.1 The KIP mentions "The controller
> considers
> > > > the
> > > > > > topic
> > > > > > > > > > > > partition is
> > > > > > > > > > > > > > > > deleted only when it determines that there
> are no
> > > > log
> > > > > > > > segments
> > > > > > > > > > > for
> > > > > > > > > > > > that
> > > > > > > > > > > > > > > > topic partition by using RLMM". How is this
> done?
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > It uses RLMM#listSegments() returns all the
> > > > segments
> > > > > > for
> > > > > > > > the
> > > > > > > > > > > given
> > > > > > > > > > > > topic
> > > > > > > > > > > > > > > > partition.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 600.2 "If the delete option is enabled then
> the
> > > > leader
> > > > > > > > will stop
> > > > > > > > > > > > RLM task
> > > > > > > > > > > > > > > > and stop processing and it sets all the
> remote
> > > log
> > > > > > segment
> > > > > > > > > > > > metadata of
> > > > > > > > > > > > > > > > that partition with a delete marker and
> publishes
> > > > them
> > > > > > to
> > > > > > > > RLMM."
> > > > > > > > > > > We
> > > > > > > > > > > > > > > > discussed this earlier. When a topic is being
> > > > deleted,
> > > > > > > > there may
> > > > > > > > > > > > not be a
> > > > > > > > > > > > > > > > leader for the deleted partition.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > This is a good point. As suggested in the
> > > meeting,
> > > > we
> > > > > > will
> > > > > > > > add a
> > > > > > > > > > > > separate
> > > > > > > > > > > > > > > > section for topic/partition deletion
> lifecycle
> > > and
> > > > this
> > > > > > > > scenario
> > > > > > > > > > > > will be
> > > > > > > > > > > > > > > > addressed.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 601. Unclean leader election
> > > > > > > > > > > > > > > > 601.1 Scenario 1: new empty follower
> > > > > > > > > > > > > > > > After step 1, the follower restores up to
> offset
> > > > 3. So
> > > > > > why
> > > > > > > > does
> > > > > > > > > > > it
> > > > > > > > > > > > have
> > > > > > > > > > > > > > > > LE-2 <
> https://issues.apache.org/jira/browse/LE-2
> > > >
> > > > at
> > > > > > > > offset 5?
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Nice catch. It was showing the leader epoch
> > > fetched
> > > > > > from
> > > > > > > > the
> > > > > > > > > > > remote
> > > > > > > > > > > > > > > > storage. It should be shown with the
> truncated
> > > till
> > > > > > offset
> > > > > > > > 3.
> > > > > > > > > > > > Updated the
> > > > > > > > > > > > > > > > KIP.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 601.2 senario 5: After Step 3, leader A has
> > > > > > inconsistent
> > > > > > > > data
> > > > > > > > > > > > between its
> > > > > > > > > > > > > > > > local and the tiered data. For example.
> offset 3
> > > > has
> > > > > > msg 3
> > > > > > > > LE-0
> > > > > > > > > > > > <https://issues.apache.org/jira/browse/LE-0>
> locally,
> > > > > > > > > > > > > > > > but msg 5 LE-1 <
> > > > > > https://issues.apache.org/jira/browse/LE-1>
> > > > > > > > in
> > > > > > > > > > > > the remote store. While it's ok for the unclean
> leader
> > > > > > > > > > > > > > > > to lose data, it should still return
> consistent
> > > > data,
> > > > > > > > whether
> > > > > > > > > > > it's
> > > > > > > > > > > > from
> > > > > > > > > > > > > > > > the local or the remote store.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > There is no inconsistency here as LE-0
> > > > > > > > > > > > <https://issues.apache.org/jira/browse/LE-0>
> offsets are
> > > > [0,
> > > > > > 4]
> > > > > > > > and LE-2
> > > > > > > > > > > > <https://issues.apache.org/jira/browse/LE-2>:
> > > > > > > > > > > > > > > > [5, ]. It will always get the right records
> for
> > > the
> > > > > > given
> > > > > > > > offset
> > > > > > > > > > > > and
> > > > > > > > > > > > > > > > leader epoch. In case of remote, RSM is
> invoked
> > > to
> > > > get
> > > > > > the
> > > > > > > > remote
> > > > > > > > > > > > log
> > > > > > > > > > > > > > > > segment that contains the given offset with
> the
> > > > leader
> > > > > > > > epoch.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 601.4 It seems that retention is based on
> > > > > > > > > > > > > > > > listRemoteLogSegments(TopicPartition
> > > > topicPartition,
> > > > > > long
> > > > > > > > > > > > leaderEpoch).
> > > > > > > > > > > > > > > > When there is an unclean leader election,
> it's
> > > > possible
> > > > > > > > for the
> > > > > > > > > > > new
> > > > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > > to not to include certain epochs in its epoch
> > > > cache.
> > > > > > How
> > > > > > > > are
> > > > > > > > > > > remote
> > > > > > > > > > > > > > > > segments associated with those epochs being
> > > > cleaned?
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > That is a good point. This leader will also
> > > > cleanup the
> > > > > > > > epochs
> > > > > > > > > > > > earlier to
> > > > > > > > > > > > > > > > its start leader epoch and delete those
> segments.
> > > > It
> > > > > > gets
> > > > > > > > the
> > > > > > > > > > > > earliest
> > > > > > > > > > > > > > > > epoch for a partition and starts deleting
> > > segments
> > > > from
> > > > > > > > that
> > > > > > > > > > > leader
> > > > > > > > > > > > > > > epoch.
> > > > > > > > > > > > > > > > We need one more API in RLMM to get the
> earliest
> > > > leader
> > > > > > > > epoch.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 601.5 The KIP discusses the handling of
> unclean
> > > > leader
> > > > > > > > elections
> > > > > > > > > > > > for user
> > > > > > > > > > > > > > > > topics. What about unclean leader elections
> on
> > > > > > > > > > > > > > > > __remote_log_segment_metadata?
> > > > > > > > > > > > > > > > This is the same as other system topics like
> > > > > > > > consumer_offsets,
> > > > > > > > > > > > > > > > __transaction_state topics. As discussed in
> the
> > > > > > meeting,
> > > > > > > > we will
> > > > > > > > > > > > add the
> > > > > > > > > > > > > > > > behavior of __remote_log_segment_metadata
> topic’s
> > > > > > unclean
> > > > > > > > leader
> > > > > > > > > > > > > > > > truncation.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 602. It would be useful to clarify the
> > > limitations
> > > > in
> > > > > > the
> > > > > > > > initial
> > > > > > > > > > > > > > > release.
> > > > > > > > > > > > > > > > The KIP mentions not supporting compacted
> topics.
> > > > What
> > > > > > > > about JBOD
> > > > > > > > > > > > and
> > > > > > > > > > > > > > > > changing the configuration of a topic from
> delete
> > > > to
> > > > > > > > compact
> > > > > > > > > > > after
> > > > > > > > > > > > > > > remote.
> > > > > > > > > > > > > > > > log. storage. enable (
> > > > > > http://remote.log.storage.enable/
> > > > > > > > ) is
> > > > > > > > > > > > enabled?
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > This was updated in the KIP earlier.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 603. RLM leader tasks:
> > > > > > > > > > > > > > > > 603.1"It checks for rolled over LogSegments
> > > (which
> > > > have
> > > > > > > > the last
> > > > > > > > > > > > message
> > > > > > > > > > > > > > > > offset less than last stable offset of that
> topic
> > > > > > > > partition) and
> > > > > > > > > > > > copies
> > > > > > > > > > > > > > > > them along with their offset/time/transaction
> > > > indexes
> > > > > > and
> > > > > > > > leader
> > > > > > > > > > > > epoch
> > > > > > > > > > > > > > > > cache to the remote tier." It needs to copy
> the
> > > > > > producer
> > > > > > > > snapshot
> > > > > > > > > > > > too.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Right. It copies producer snapshots too as
> > > > mentioned in
> > > > > > > > > > > > LogSegmentData.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 603.2 "Local logs are not cleaned up till
> those
> > > > > > segments
> > > > > > > > are
> > > > > > > > > > > copied
> > > > > > > > > > > > > > > > successfully to remote even though their
> > > retention
> > > > > > > > time/size is
> > > > > > > > > > > > reached"
> > > > > > > > > > > > > > > > This seems weird. If the tiering stops
> because
> > > the
> > > > > > remote
> > > > > > > > store
> > > > > > > > > > > is
> > > > > > > > > > > > not
> > > > > > > > > > > > > > > > available, we don't want the local data to
> grow
> > > > > > forever.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > It was clarified in the discussion that the
> > > > comment was
> > > > > > > > more
> > > > > > > > > > > about
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > > local storage goes beyond the log.retention.
> The
> > > > above
> > > > > > > > statement
> > > > > > > > > > > > is about
> > > > > > > > > > > > > > > > local.log.retention but not for the complete
> > > > > > > > log.retention. When
> > > > > > > > > > > it
> > > > > > > > > > > > > > > > reaches the log.retention then it will
> delete the
> > > > local
> > > > > > > > logs even
> > > > > > > > > > > > though
> > > > > > > > > > > > > > > > those are not copied to remote storage.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 604. "RLM maintains a bounded cache(possibly
> LRU)
> > > > of
> > > > > > the
> > > > > > > > index
> > > > > > > > > > > > files of
> > > > > > > > > > > > > > > > remote log segments to avoid multiple index
> > > fetches
> > > > > > from
> > > > > > > > the
> > > > > > > > > > > remote
> > > > > > > > > > > > > > > > storage. These indexes can be used in the
> same
> > > way
> > > > as
> > > > > > local
> > > > > > > > > > > segment
> > > > > > > > > > > > > > > > indexes are used." Could you provide more
> details
> > > > on
> > > > > > this?
> > > > > > > > Are
> > > > > > > > > > > the
> > > > > > > > > > > > > > > indexes
> > > > > > > > > > > > > > > > cached in memory or on disk? If on disk,
> where
> > > are
> > > > they
> > > > > > > > stored?
> > > > > > > > > > > > Are the
> > > > > > > > > > > > > > > > cached indexes bound by a certain size?
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > These are cached on disk and stored in
> log.dir
> > > > with a
> > > > > > name
> > > > > > > > > > > > > > > > “__remote_log_index_cache”. They are bound
> by the
> > > > total
> > > > > > > > size.
> > > > > > > > > > > This
> > > > > > > > > > > > will
> > > > > > > > > > > > > > > be
> > > > > > > > > > > > > > > > exposed as a user configuration,
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 605. BuildingRemoteLogAux
> > > > > > > > > > > > > > > > 605.1 In this section, two options are
> listed.
> > > > Which
> > > > > > one is
> > > > > > > > > > > chosen?
> > > > > > > > > > > > > > > > Option-2, updated the KIP.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 605.2 In option 2, it says "Build the local
> > > leader
> > > > > > epoch
> > > > > > > > cache by
> > > > > > > > > > > > cutting
> > > > > > > > > > > > > > > > the leader epoch sequence received from
> remote
> > > > storage
> > > > > > to
> > > > > > > > [LSO,
> > > > > > > > > > > > ELO].
> > > > > > > > > > > > > > > (LSO
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > = log start offset)." We need to do the same
> > > thing
> > > > for
> > > > > > the
> > > > > > > > > > > producer
> > > > > > > > > > > > > > > > snapshot. However, it's hard to cut the
> producer
> > > > > > snapshot
> > > > > > > > to an
> > > > > > > > > > > > earlier
> > > > > > > > > > > > > > > > offset. Another option is to simply take the
> > > > lastOffset
> > > > > > > > from the
> > > > > > > > > > > > remote
> > > > > > > > > > > > > > > > segment and use that as the starting fetch
> offset
> > > > in
> > > > > > the
> > > > > > > > > > > follower.
> > > > > > > > > > > > This
> > > > > > > > > > > > > > > > avoids the need for cutting.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Right, this was mentioned in the
> “transactional
> > > > > > support”
> > > > > > > > section
> > > > > > > > > > > > about
> > > > > > > > > > > > > > > > adding these details.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 606. ListOffsets: Since we need a version
> bump,
> > > > could
> > > > > > you
> > > > > > > > > > > document
> > > > > > > > > > > > it
> > > > > > > > > > > > > > > > under a protocol change section?
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Sure, we will update the KIP.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 607. "LogStartOffset of a topic can point to
> > > > either of
> > > > > > > > local
> > > > > > > > > > > > segment or
> > > > > > > > > > > > > > > > remote segment but it is initialised and
> > > > maintained in
> > > > > > the
> > > > > > > > Log
> > > > > > > > > > > > class like
> > > > > > > > > > > > > > > > now. This is already maintained in `Log`
> class
> > > > while
> > > > > > > > loading the
> > > > > > > > > > > > logs and
> > > > > > > > > > > > > > > > it can also be fetched from
> > > > RemoteLogMetadataManager."
> > > > > > > > What will
> > > > > > > > > > > > happen
> > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > the existing logic (e.g. log recovery) that
> > > > currently
> > > > > > > > depends on
> > > > > > > > > > > > > > > > logStartOffset but assumes it's local?
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > They use a field called localLogStartOffset
> which
> > > > is
> > > > > > the
> > > > > > > > local
> > > > > > > > > > > log
> > > > > > > > > > > > start
> > > > > > > > > > > > > > > > offset..
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 608. Handle expired remote segment: How does
> it
> > > > pick
> > > > > > up new
> > > > > > > > > > > > > > > logStartOffset
> > > > > > > > > > > > > > > > from deleteRecords?
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Good point. This was not addressed in the
> KIP.
> > > Will
> > > > > > update
> > > > > > > > the
> > > > > > > > > > > KIP
> > > > > > > > > > > > on how
> > > > > > > > > > > > > > > > the RLM task handles this scenario.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 609. RLMM message format:
> > > > > > > > > > > > > > > > 609.1 It includes both MaxTimestamp and
> > > > EventTimestamp.
> > > > > > > > Where
> > > > > > > > > > > does
> > > > > > > > > > > > it get
> > > > > > > > > > > > > > > > both since the message in the log only
> contains
> > > one
> > > > > > > > timestamp?
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > `EventTimeStamp` is the timestamp at which
> that
> > > > segment
> > > > > > > > metadata
> > > > > > > > > > > > event is
> > > > > > > > > > > > > > > > generated. This is more for audits.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 609.2 If we change just the state (e.g. to
> > > > > > > > DELETE_STARTED), it
> > > > > > > > > > > > seems it's
> > > > > > > > > > > > > > > > wasteful to have to include all other fields
> not
> > > > > > changed.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > This is a good point. We thought about
> > > incremental
> > > > > > > > updates. But
> > > > > > > > > > > we
> > > > > > > > > > > > want
> > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > make sure all the events are in the expected
> > > order
> > > > and
> > > > > > take
> > > > > > > > > > > action
> > > > > > > > > > > > based
> > > > > > > > > > > > > > > > on the latest event. Will think through the
> > > > approaches
> > > > > > in
> > > > > > > > detail
> > > > > > > > > > > > and
> > > > > > > > > > > > > > > > update here.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 609.3 Could you document which process makes
> the
> > > > > > following
> > > > > > > > > > > > transitions
> > > > > > > > > > > > > > > > DELETE_MARKED, DELETE_STARTED,
> DELETE_FINISHED?
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Okay, will document more details.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 610. remote.log.reader.max.pending.tasks:
> > > "Maximum
> > > > > > remote
> > > > > > > > log
> > > > > > > > > > > > reader
> > > > > > > > > > > > > > > > thread pool task queue size. If the task
> queue is
> > > > full,
> > > > > > > > broker
> > > > > > > > > > > > will stop
> > > > > > > > > > > > > > > > reading remote log segments." What does the
> > > broker
> > > > do
> > > > > > if
> > > > > > > > the
> > > > > > > > > > > queue
> > > > > > > > > > > > is
> > > > > > > > > > > > > > > > full?
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > It returns an error for this topic partition.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 611. What do we return if the request
> > > offset/epoch
> > > > > > doesn't
> > > > > > > > exist
> > > > > > > > > > > > in the
> > > > > > > > > > > > > > > > following API?
> > > > > > > > > > > > > > > > RemoteLogSegmentMetadata
> > > > > > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > > > > > > > > topicPartition, long offset, int
> epochForOffset)
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > This returns null. But we prefer to update
> the
> > > > return
> > > > > > type
> > > > > > > > as
> > > > > > > > > > > > Optional
> > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > return Empty if that does not exist.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > Satish.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > On Tue, Sep 1, 2020 at 9:45 AM Jun Rao < jun@
> > > > > > confluent.
> > > > > > > > io (
> > > > > > > > > > > > > > > > jun@confluent.io ) > wrote:
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >> Hi, Satish,
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >> Thanks for the updated KIP. Made another
> pass. A
> > > > few
> > > > > > more
> > > > > > > > > > > comments
> > > > > > > > > > > > > > > below.
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >> 600. The topic deletion logic needs more
> > > details.
> > > > > > > > > > > > > > > >> 600.1 The KIP mentions "The controller
> considers
> > > > the
> > > > > > topic
> > > > > > > > > > > > partition is
> > > > > > > > > > > > > > > >> deleted only when it determines that there
> are
> > > no
> > > > log
> > > > > > > > segments
> > > > > > > > > > > > for that
> > > > > > > > > > > > > > > >> topic partition by using RLMM". How is this
> > > done?
> > > > > > 600.2
> > > > > > > > "If the
> > > > > > > > > > > > delete
> > > > > > > > > > > > > > > >> option is enabled then the leader will stop
> RLM
> > > > task
> > > > > > and
> > > > > > > > stop
> > > > > > > > > > > > processing
> > > > > > > > > > > > > > > >> and it sets all the remote log segment
> metadata
> > > of
> > > > > > that
> > > > > > > > > > > partition
> > > > > > > > > > > > with a
> > > > > > > > > > > > > > > >> delete marker and publishes them to RLMM."
> We
> > > > > > discussed
> > > > > > > > this
> > > > > > > > > > > > earlier.
> > > > > > > > > > > > > > > When
> > > > > > > > > > > > > > > >> a topic is being deleted, there may not be a
> > > > leader
> > > > > > for
> > > > > > > > the
> > > > > > > > > > > > deleted
> > > > > > > > > > > > > > > >> partition.
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >> 601. Unclean leader election
> > > > > > > > > > > > > > > >> 601.1 Scenario 1: new empty follower
> > > > > > > > > > > > > > > >> After step 1, the follower restores up to
> offset
> > > > 3. So
> > > > > > > > why does
> > > > > > > > > > > > it have
> > > > > > > > > > > > > > > >> LE-2 <
> > > https://issues.apache.org/jira/browse/LE-2>
> > > > at
> > > > > > > > offset 5?
> > > > > > > > > > > > > > > >> 601.2 senario 5: After Step 3, leader A has
> > > > > > inconsistent
> > > > > > > > data
> > > > > > > > > > > > between
> > > > > > > > > > > > > > > its
> > > > > > > > > > > > > > > >> local and the tiered data. For example.
> offset 3
> > > > has
> > > > > > msg
> > > > > > > > 3 LE-0
> > > > > > > > > > > > <https://issues.apache.org/jira/browse/LE-0>
> locally,
> > > > > > > > > > > > > > > >> but msg 5 LE-1 <
> > > > > > > > https://issues.apache.org/jira/browse/LE-1> in
> > > > > > > > > > > > the remote store. While it's ok for the unclean
> leader
> > > > > > > > > > > > > > > >> to lose data, it should still return
> consistent
> > > > data,
> > > > > > > > whether
> > > > > > > > > > > > it's from
> > > > > > > > > > > > > > > >> the local or the remote store.
> > > > > > > > > > > > > > > >> 601.3 The follower picks up log start offset
> > > > using the
> > > > > > > > following
> > > > > > > > > > > > api.
> > > > > > > > > > > > > > > >> Suppose that we have 3 remote segments (LE,
> > > > > > > > SegmentStartOffset)
> > > > > > > > > > > > as (2,
> > > > > > > > > > > > > > > >> 10),
> > > > > > > > > > > > > > > >> (3, 20) and (7, 15) due to an unclean leader
> > > > election.
> > > > > > > > Using the
> > > > > > > > > > > > > > > following
> > > > > > > > > > > > > > > >> api will cause logStartOffset to go backward
> > > from
> > > > 20
> > > > > > to
> > > > > > > > 15. How
> > > > > > > > > > > > do we
> > > > > > > > > > > > > > > >> prevent that?
> > > > > > > > > > > > > > > >> earliestLogOffset(TopicPartition
> topicPartition,
> > > > int
> > > > > > > > > > > leaderEpoch)
> > > > > > > > > > > > 601.4
> > > > > > > > > > > > > > > It
> > > > > > > > > > > > > > > >> seems that retention is based on
> > > > > > > > > > > > > > > >> listRemoteLogSegments(TopicPartition
> > > > topicPartition,
> > > > > > long
> > > > > > > > > > > > leaderEpoch).
> > > > > > > > > > > > > > > >> When there is an unclean leader election,
> it's
> > > > > > possible
> > > > > > > > for the
> > > > > > > > > > > > new
> > > > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > >> to not to include certain epochs in its
> epoch
> > > > cache.
> > > > > > How
> > > > > > > > are
> > > > > > > > > > > > remote
> > > > > > > > > > > > > > > >> segments associated with those epochs being
> > > > cleaned?
> > > > > > > > 601.5 The
> > > > > > > > > > > KIP
> > > > > > > > > > > > > > > >> discusses the handling of unclean leader
> > > > elections for
> > > > > > > > user
> > > > > > > > > > > > topics. What
> > > > > > > > > > > > > > > >> about unclean leader elections on
> > > > > > > > > > > > > > > >> __remote_log_segment_metadata?
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >> 602. It would be useful to clarify the
> > > > limitations in
> > > > > > the
> > > > > > > > > > > initial
> > > > > > > > > > > > > > > release.
> > > > > > > > > > > > > > > >> The KIP mentions not supporting compacted
> > > topics.
> > > > What
> > > > > > > > about
> > > > > > > > > > > JBOD
> > > > > > > > > > > > and
> > > > > > > > > > > > > > > >> changing the configuration of a topic from
> > > delete
> > > > to
> > > > > > > > compact
> > > > > > > > > > > after
> > > > > > > > > > > > > > > remote.
> > > > > > > > > > > > > > > >> log. storage. enable (
> > > > > > http://remote.log.storage.enable/
> > > > > > > > ) is
> > > > > > > > > > > > enabled?
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >> 603. RLM leader tasks:
> > > > > > > > > > > > > > > >> 603.1"It checks for rolled over LogSegments
> > > (which
> > > > > > have
> > > > > > > > the last
> > > > > > > > > > > > message
> > > > > > > > > > > > > > > >> offset less than last stable offset of that
> > > topic
> > > > > > > > partition) and
> > > > > > > > > > > > copies
> > > > > > > > > > > > > > > >> them along with their
> offset/time/transaction
> > > > indexes
> > > > > > and
> > > > > > > > leader
> > > > > > > > > > > > epoch
> > > > > > > > > > > > > > > >> cache to the remote tier." It needs to copy
> the
> > > > > > producer
> > > > > > > > > > > snapshot
> > > > > > > > > > > > too.
> > > > > > > > > > > > > > > >> 603.2 "Local logs are not cleaned up till
> those
> > > > > > segments
> > > > > > > > are
> > > > > > > > > > > > copied
> > > > > > > > > > > > > > > >> successfully to remote even though their
> > > retention
> > > > > > > > time/size is
> > > > > > > > > > > > reached"
> > > > > > > > > > > > > > > >> This seems weird. If the tiering stops
> because
> > > the
> > > > > > remote
> > > > > > > > store
> > > > > > > > > > > > is not
> > > > > > > > > > > > > > > >> available, we don't want the local data to
> grow
> > > > > > forever.
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >> 604. "RLM maintains a bounded cache(possibly
> > > LRU)
> > > > of
> > > > > > the
> > > > > > > > index
> > > > > > > > > > > > files of
> > > > > > > > > > > > > > > >> remote log segments to avoid multiple index
> > > > fetches
> > > > > > from
> > > > > > > > the
> > > > > > > > > > > > remote
> > > > > > > > > > > > > > > >> storage. These indexes can be used in the
> same
> > > > way as
> > > > > > > > local
> > > > > > > > > > > > segment
> > > > > > > > > > > > > > > >> indexes are used." Could you provide more
> > > details
> > > > on
> > > > > > > > this? Are
> > > > > > > > > > > the
> > > > > > > > > > > > > > > indexes
> > > > > > > > > > > > > > > >> cached in memory or on disk? If on disk,
> where
> > > are
> > > > > > they
> > > > > > > > stored?
> > > > > > > > > > > > Are the
> > > > > > > > > > > > > > > >> cached indexes bound by a certain size?
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >> 605. BuildingRemoteLogAux
> > > > > > > > > > > > > > > >> 605.1 In this section, two options are
> listed.
> > > > Which
> > > > > > one
> > > > > > > > is
> > > > > > > > > > > > chosen?
> > > > > > > > > > > > > > > 605.2
> > > > > > > > > > > > > > > >> In option 2, it says "Build the local leader
> > > epoch
> > > > > > cache
> > > > > > > > by
> > > > > > > > > > > > cutting the
> > > > > > > > > > > > > > > >> leader epoch sequence received from remote
> > > > storage to
> > > > > > > > [LSO,
> > > > > > > > > > > ELO].
> > > > > > > > > > > > (LSO
> > > > > > > > > > > > > > > >> = log start offset)." We need to do the same
> > > thing
> > > > > > for the
> > > > > > > > > > > > producer
> > > > > > > > > > > > > > > >> snapshot. However, it's hard to cut the
> producer
> > > > > > snapshot
> > > > > > > > to an
> > > > > > > > > > > > earlier
> > > > > > > > > > > > > > > >> offset. Another option is to simply take the
> > > > > > lastOffset
> > > > > > > > from the
> > > > > > > > > > > > remote
> > > > > > > > > > > > > > > >> segment and use that as the starting fetch
> > > offset
> > > > in
> > > > > > the
> > > > > > > > > > > > follower. This
> > > > > > > > > > > > > > > >> avoids the need for cutting.
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >> 606. ListOffsets: Since we need a version
> bump,
> > > > could
> > > > > > you
> > > > > > > > > > > > document it
> > > > > > > > > > > > > > > >> under a protocol change section?
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >> 607. "LogStartOffset of a topic can point to
> > > > either of
> > > > > > > > local
> > > > > > > > > > > > segment or
> > > > > > > > > > > > > > > >> remote segment but it is initialised and
> > > > maintained in
> > > > > > > > the Log
> > > > > > > > > > > > class
> > > > > > > > > > > > > > > like
> > > > > > > > > > > > > > > >> now. This is already maintained in `Log`
> class
> > > > while
> > > > > > > > loading the
> > > > > > > > > > > > logs
> > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > >> it can also be fetched from
> > > > RemoteLogMetadataManager."
> > > > > > > > What will
> > > > > > > > > > > > happen
> > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > >> the existing logic (e.g. log recovery) that
> > > > currently
> > > > > > > > depends on
> > > > > > > > > > > > > > > >> logStartOffset but assumes it's local?
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >> 608. Handle expired remote segment: How
> does it
> > > > pick
> > > > > > up
> > > > > > > > new
> > > > > > > > > > > > > > > logStartOffset
> > > > > > > > > > > > > > > >> from deleteRecords?
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >> 609. RLMM message format:
> > > > > > > > > > > > > > > >> 609.1 It includes both MaxTimestamp and
> > > > > > EventTimestamp.
> > > > > > > > Where
> > > > > > > > > > > > does it
> > > > > > > > > > > > > > > get
> > > > > > > > > > > > > > > >> both since the message in the log only
> contains
> > > > one
> > > > > > > > timestamp?
> > > > > > > > > > > > 609.2 If
> > > > > > > > > > > > > > > we
> > > > > > > > > > > > > > > >> change just the state (e.g. to
> DELETE_STARTED),
> > > it
> > > > > > seems
> > > > > > > > it's
> > > > > > > > > > > > wasteful
> > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > >> have to include all other fields not
> changed.
> > > > 609.3
> > > > > > Could
> > > > > > > > you
> > > > > > > > > > > > document
> > > > > > > > > > > > > > > >> which process makes the following
> transitions
> > > > > > > > DELETE_MARKED,
> > > > > > > > > > > > > > > >> DELETE_STARTED, DELETE_FINISHED?
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >> 610. remote.log.reader.max.pending.tasks:
> > > "Maximum
> > > > > > remote
> > > > > > > > log
> > > > > > > > > > > > reader
> > > > > > > > > > > > > > > >> thread pool task queue size. If the task
> queue
> > > is
> > > > > > full,
> > > > > > > > broker
> > > > > > > > > > > > will stop
> > > > > > > > > > > > > > > >> reading remote log segments." What does the
> > > > broker do
> > > > > > if
> > > > > > > > the
> > > > > > > > > > > > queue is
> > > > > > > > > > > > > > > >> full?
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >> 611. What do we return if the request
> > > offset/epoch
> > > > > > > > doesn't exist
> > > > > > > > > > > > in the
> > > > > > > > > > > > > > > >> following API?
> > > > > > > > > > > > > > > >> RemoteLogSegmentMetadata
> > > > > > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > > > > > > > >> topicPartition, long offset, int
> epochForOffset)
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >> Jun
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >> On Mon, Aug 31, 2020 at 11:19 AM Satish
> Duggana
> > > <
> > > > > > satish.
> > > > > > > > > > > duggana@
> > > > > > > > > > > > > > > gmail. com
> > > > > > > > > > > > > > > >> ( satish.duggana@gmail.com ) > wrote:
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>> KIP is updated with
> > > > > > > > > > > > > > > >>> - Remote log segment metadata topic message
> > > > > > > > format/schema.
> > > > > > > > > > > > > > > >>> - Added remote log segment metadata state
> > > > > > transitions and
> > > > > > > > > > > > explained how
> > > > > > > > > > > > > > > >>> the deletion of segments is handled,
> including
> > > > the
> > > > > > case
> > > > > > > > of
> > > > > > > > > > > > partition
> > > > > > > > > > > > > > > >>> deletions.
> > > > > > > > > > > > > > > >>> - Added a few more limitations in the "Non
> > > goals"
> > > > > > > > section.
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>> Thanks,
> > > > > > > > > > > > > > > >>> Satish.
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>> On Thu, Aug 27, 2020 at 12:42 AM Harsha Ch
> <
> > > > harsha.
> > > > > > ch@
> > > > > > > > > > > gmail.
> > > > > > > > > > > > com (
> > > > > > > > > > > > > > > >>> harsha.ch@gmail.com ) > wrote:
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>> Updated the KIP with Meeting Notes section
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>> https:/ / cwiki. apache. org/ confluence/
> > > > display/
> > > > > > KAFKA/
> > > > > > > > > > > > > > > KIP-405 <
> > > > https://issues.apache.org/jira/browse/KIP-405>
> > > > > > > > > > > >
> > > > %3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> > > > > > > > > > > > > > > >>> (
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > >
> > > > > >
> > > >
> > >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-405%3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> > > > > > > > > > > > > > > >>> )
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>> On Tue, Aug 25, 2020 at 1:03 PM Jun Rao <
> jun@
> > > > > > > > confluent. io
> > > > > > > > > > > (
> > > > > > > > > > > > > > > >>>> jun@confluent.io ) > wrote:
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>> Hi, Harsha,
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>> Thanks for the summary. Could you add the
> > > > summary
> > > > > > and
> > > > > > > > the
> > > > > > > > > > > > recording
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>> link to
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>> the last section of
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>> https:/ / cwiki. apache. org/ confluence/
> > > > display/
> > > > > > KAFKA/
> > > > > > > > > > > > > > > Kafka+Improvement+Proposals
> > > > > > > > > > > > > > > >>> (
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > >
> > > > > >
> > > >
> > >
> https://cwiki.apache.org/confluence/display/KAFKA/Kafka+Improvement+Proposals
> > > > > > > > > > > > > > > >>> )
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>> ?
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>> Jun
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>> On Tue, Aug 25, 2020 at 11:12 AM Harsha
> > > > > > Chintalapani <
> > > > > > > > kafka@
> > > > > > > > > > > > > > > harsha. io (
> > > > > > > > > > > > > > > >>>>> kafka@harsha.io ) > wrote:
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>> Thanks everyone for attending the
> meeting
> > > > today.
> > > > > > > > > > > > > > > >>>>>> Here is the recording
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>> https:/ / drive. google. com/ file/ d/
> > > > > > > > > > > > > > > 14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/
> view?usp=sharing
> > > > > > > > > > > > > > > >>> (
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > >
> > > > > >
> > > >
> > >
> https://drive.google.com/file/d/14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/view?usp=sharing
> > > > > > > > > > > > > > > >>> )
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>> Notes:
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>> 1. KIP is updated with follower fetch
> > > > protocol and
> > > > > > > > ready to
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>> reviewed
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>> 2. Satish to capture schema of internal
> > > > metadata
> > > > > > > > topic in
> > > > > > > > > > > the
> > > > > > > > > > > > KIP
> > > > > > > > > > > > > > > >>>>>> 3. We will update the KIP with details
> of
> > > > > > different
> > > > > > > > cases
> > > > > > > > > > > > > > > >>>>>> 4. Test plan will be captured in a doc
> and
> > > > will
> > > > > > add
> > > > > > > > to the
> > > > > > > > > > > KIP
> > > > > > > > > > > > > > > >>>>>> 5. Add a section "Limitations" to
> capture
> > > the
> > > > > > > > capabilities
> > > > > > > > > > > > that
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>> will
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>> be
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>> introduced with this KIP and what will
> not
> > > be
> > > > > > covered
> > > > > > > > in
> > > > > > > > > > > this
> > > > > > > > > > > > KIP.
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>> Please add to it I missed anything. Will
> > > > produce a
> > > > > > > > formal
> > > > > > > > > > > > meeting
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>> notes
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>> from next meeting onwards.
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>> Thanks,
> > > > > > > > > > > > > > > >>>>>> Harsha
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>> On Mon, Aug 24, 2020 at 9:42 PM, Ying
> Zheng
> > > <
> > > > > > yingz@
> > > > > > > > uber.
> > > > > > > > > > > > com.
> > > > > > > > > > > > > > > invalid (
> > > > > > > > > > > > > > > >>>>>> yingz@uber.com.invalid ) > wrote:
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> We did some basic feature tests at
> Uber.
> > > The
> > > > test
> > > > > > > > cases and
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>> results are
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> shared in this google doc:
> > > > > > > > > > > > > > > >>>>>>> https:/ / docs. google. com/
> spreadsheets/
> > > > d/ (
> > > > > > > > > > > > > > > >>>>>>>
> https://docs.google.com/spreadsheets/d/ )
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > >
> > > 1XhNJqjzwXvMCcAOhEH0sSXU6RTvyoSf93DHF-YMfGLk/edit?usp=sharing
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> The performance test results were
> already
> > > > shared
> > > > > > in
> > > > > > > > the KIP
> > > > > > > > > > > > last
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>> month.
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> On Mon, Aug 24, 2020 at 11:10 AM
> Harsha Ch
> > > <
> > > > > > harsha.
> > > > > > > > ch@
> > > > > > > > > > > > gmail.
> > > > > > > > > > > > > > > com (
> > > > > > > > > > > > > > > >>>>>>> harsha.ch@gmail.com ) >
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>> wrote:
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> "Understand commitments towards driving
> > > > design &
> > > > > > > > > > > > implementation of
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>> the
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>> KIP
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> further and how it aligns with
> participant
> > > > > > interests
> > > > > > > > in
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>> contributing to
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>> the
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> efforts (ex: in the context of Uber’s
> Q3/Q4
> > > > > > > > roadmap)." What
> > > > > > > > > > > > is that
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>> about?
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> On Mon, Aug 24, 2020 at 11:05 AM
> Kowshik
> > > > > > Prakasam <
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>> kprakasam@ confluent. io (
> > > > kprakasam@confluent.io
> > > > > > ) >
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> wrote:
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> Hi Harsha,
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> The following google doc contains a
> > > proposal
> > > > for
> > > > > > > > temporary
> > > > > > > > > > > > agenda
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>> for
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>> the
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> KIP-405 <
> > > > > > > > https://issues.apache.org/jira/browse/KIP-405> <
> > > > > > > > > > > > https:/ / issues. apache. org/ jira/ browse/ KIP-405
> > > > > > > > > > > > <https://issues.apache.org/jira/browse/KIP-405> (
> > > > > > > > > > > > > > > >>>>>>>
> > > > https://issues.apache.org/jira/browse/KIP-405 )
> > > > > > >
> > > > > > > > sync
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>> meeting
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> tomorrow:
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> https:/ / docs. google. com/ document/
> d/ (
> > > > > > > > > > > > > > > >>>>>>> https://docs.google.com/document/d/ )
> > > > > > > > > > > > > > > >>>>>>>
> > > > 1pqo8X5LU8TpwfC_iqSuVPezhfCfhGkbGN2TqiPA3LBU/edit
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> .
> > > > > > > > > > > > > > > >>>>>>> Please could you add it to the Google
> > > > calendar
> > > > > > > > invite?
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> Thank you.
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> Cheers,
> > > > > > > > > > > > > > > >>>>>>> Kowshik
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> On Thu, Aug 20, 2020 at 10:58 AM
> Harsha Ch
> > > <
> > > > > > harsha.
> > > > > > > > ch@
> > > > > > > > > > > > gmail.
> > > > > > > > > > > > > > > com (
> > > > > > > > > > > > > > > >>>>>>> harsha.ch@gmail.com ) >
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>> wrote:
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> Hi All,
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> Scheduled a meeting for Tuesday 9am -
> 10am.
> > > > I can
> > > > > > > > record
> > > > > > > > > > > and
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>> upload for
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> community to be able to follow the
> > > > discussion.
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> Jun, please add the required folks on
> > > > confluent
> > > > > > side.
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> Thanks,
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> Harsha
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> On Thu, Aug 20, 2020 at 12:33 AM,
> Alexandre
> > > > > > Dupriez <
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>> alexandre.dupriez@
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> gmail. com ( http://gmail.com/ ) >
> wrote:
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> Hi Jun,
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> Many thanks for your initiative.
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> If you like, I am happy to attend at
> the
> > > > time you
> > > > > > > > > > > suggested.
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> Many thanks,
> > > > > > > > > > > > > > > >>>>>>> Alexandre
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> Le mer. 19 août 2020 à 22:00, Harsha
> Ch <
> > > > > > harsha. ch@
> > > > > > > > > > > > gmail. com (
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>> harsha.
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> ch@ gmail. com ( ch@gmail.com ) ) > a
> > > écrit
> > > > :
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> Hi Jun,
> > > > > > > > > > > > > > > >>>>>>> Thanks. This will help a lot. Tuesday
> will
> > > > work
> > > > > > for
> > > > > > > > us.
> > > > > > > > > > > > > > > >>>>>>> -Harsha
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> On Wed, Aug 19, 2020 at 1:24 PM Jun
> Rao <
> > > > jun@
> > > > > > > > confluent.
> > > > > > > > > > > > io (
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>> jun@
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> confluent. io ( http://confluent.io/
> ) ) >
> > > > > > wrote:
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> Hi, Satish, Ying, Harsha,
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> Do you think it would be useful to
> have a
> > > > regular
> > > > > > > > virtual
> > > > > > > > > > > > meeting
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>> to
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> discuss this KIP? The goal of the
> meeting
> > > > will be
> > > > > > > > sharing
> > > > > > > > > > > > > > > >>>>>>> design/development progress and
> discussing
> > > > any
> > > > > > open
> > > > > > > > issues
> > > > > > > > > > > to
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> accelerate
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> this KIP. If so, will every Tuesday
> (from
> > > > next
> > > > > > week)
> > > > > > > > > > > 9am-10am
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> PT
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> work for you? I can help set up a Zoom
> > > > meeting,
> > > > > > > > invite
> > > > > > > > > > > > everyone who
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> might
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> be interested, have it recorded and
> shared,
> > > > etc.
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> Thanks,
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> Jun
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> On Tue, Aug 18, 2020 at 11:01 AM Satish
> > > > Duggana <
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> satish. duggana@ gmail. com ( satish.
> > > > duggana@
> > > > > > > > gmail. com
> > > > > > > > > > > (
> > > > > > > > > > > > > > > >>>>>>> satish.duggana@gmail.com ) ) >
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> wrote:
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> Hi Kowshik,
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> Thanks for looking into the KIP and
> sending
> > > > your
> > > > > > > > comments.
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > > >>>>>>> 5001. Under the section "Follower fetch
> > > > protocol
> > > > > > in
> > > > > > > > > > > detail",
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > >>>>>>> next-local-offset is the offset upto
> which
> > > > the
> > > > > > > > segments are
> > > > > > > > > > > > copied
> > > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > >
> > > >
> > >
>

Re: [DISCUSS] KIP-405: Kafka Tiered Storage

[Satish Duggana <sa...@gmail.com>]

Hi Jun,
Thanks for your comments. Please find the inline replies below.

6022. For packages used for server plugins, the convention is to
use org.apache.kafka.server. See java-based Authorizer as an example.

Sure, ‘org.apache.kafka.common.log.remote.storage’ renamed to
‘org.apache.kafka.server.log.remote.storage’.  Updated in the KIP.

9100. Do we need DeletePartitionStateRecord in flat_file_format? The flat
file captures the state of the remote segments. After a partition is
deleted, it seems that we just need to remove the partitions's remote
segments from the flat file.

DeletePartitionState might not yet have been processed by RPM and not
completed. We  will not have  that in flat  file format  once it
reaches DELETE_PARTITION_FINISHED state.

9101. Upgrade: It will be useful to allow direct upgrade from an old
version. It seems that's doable. One can just do the normal upgrade first
and wait enough time (for producer snapshots to be built), and then enable
remote storage.

Upgrade notes updates in the KIP.

9102. RemotePartitionRemover(RPM) process: Is it true that RPM starts
tracking the remote segments when RLMM.onPartitionLeadershipChanges() is
called with the broker being the leader for __remote_log_metadata
partition? If so, could we document it?

The current plan is to have that as part of RLMM and RPM uses that to
get the remote segments list. I will add this detail in the respective
sections.

Satish.

On Wed, 16 Dec 2020 at 23:55, Jun Rao <ju...@confluent.io> wrote:
>
> Hi, Satish,
>
> Thanks for the reply. A few more followup comments.
>
> 6022. For packages used for server plugins, the convention is to
> use org.apache.kafka.server. See java-based Authorizer as an example.
>
> 9100. Do we need DeletePartitionStateRecord in flat_file_format? The flat
> file captures the state of the remote segments. After a partition is
> deleted, it seems that we just need to remove the partitions's remote
> segments from the flat file.
>
> 9101. Upgrade: It will be useful to allow direct upgrade from an old
> version. It seems that's doable. One can just do the normal upgrade first
> and wait enough time (for producer snapshots to be built), and then enable
> remote storage.
>
> 9102. RemotePartitionRemover(RPM) process: Is it true that RPM starts
> tracking the remote segments when RLMM.onPartitionLeadershipChanges() is
> called with the broker being the leader for __remote_log_metadata
> partition? If so, could we document it?
>
> Jun
>
> On Tue, Dec 15, 2020 at 8:47 AM Kowshik Prakasam <kp...@confluent.io>
> wrote:
>
> > Hi Satish,
> >
> > Thanks for the updates! A few more comments below.
> >
> > 9001. Under the "Upgrade" section, there is a line mentioning: "Upgrade the
> > existing Kafka cluster to 2.7 version and allow this to run for the log
> > retention of user topics that you want to enable tiered storage. This will
> > allow all the topics to have the producer snapshots generated for each log
> > segment." -- Which associated change in AK were you referring to here? Is
> > it: https://github.com/apache/kafka/pull/7929 ? It seems like I don't see
> > it in the 2.7 release branch yet, here is the link:
> > https://github.com/apache/kafka/commits/2.7.
> >
> > 9002. Under the "Upgrade" section, the configuration mentioned is
> > 'remote.log.storage.system.enable'. However, under "Public Interfaces"
> > section the corresponding configuration is 'remote.storage.system.enable'.
> > Could we use the same one in both, maybe
> > 'remote.log.storage.system.enable'?
> >
> > 9003. Under "Per Topic Configuration", the KIP recommends setting
> > 'remote.log.storage.enable' to true at a per-topic level. It will be useful
> > to add a line that if the user wants to enable it for all topics, then they
> > should be able to set the cluster-wide default to true. Also, it will be
> > useful to mention that the KIP currently does not support setting it to
> > false (after it is set to true), and add that to the future work section.
> >
> > 9004. Under "Committed offsets file format", the sample provided shows
> > partition number and offset. Is the topic name required for identifying
> > which topic the partitions belong to?
> >
> > 9005. Under "Internal flat-file store format of remote log metadata", it
> > seems useful to specify both topic name and topic ID for debugging
> > purposes.
> >
> > 9006. Under "Internal flat-file store format of remote log metadata", the
> > description of "metadata-topic-offset" currently says "offset of the remote
> > log metadata topic from which this topic partition's remote log metadata is
> > fetched." Just for the wording, perhaps you meant to refer to the offset
> > upto which the file has been committed? i.e. "offset of the remote log
> > metadata topic upto which this topic partition's remote log metadata has
> > been committed into this file."
> >
> > 9007. Under "Internal flat-file store format of remote log metadata", the
> > schema of the payload (i.e. beyond the header) seems to contain the events
> > from the metadata topic. It seems useful to instead persist the
> > representation of the materialized state of the events, so that for the
> > same segment only the latest state is stored. Besides reducing storage
> > footprint, this also is likely to relate directly with the in-memory
> > representation of the RLMM cache (which probably is some kind of a Map with
> > key being segment ID and value being the segment state), so recovery from
> > disk will be straightforward.
> >
> > 9008. Under "Topic deletion lifecycle", step (1), it will be useful to
> > mention when in the deletion flow does the controller publish the
> > delete_partition_marked event to say that the partition is marked for
> > deletion?
> >
> > 9009. There are ~4 TODOs in the KIP. Could you please address these or
> > remove them?
> >
> > 9010. There is a reference to a Google doc on the KIP which was used
> > earlier for discussions. Please could you remove the reference, since the
> > KIP is the source of the truth?
> >
> > 9011. This feedback is from an earlier comment. In the RemoteStorageManager
> > interface, there is an API defined for each file type. For example,
> > fetchOffsetIndex, fetchTimestampIndex etc. To avoid the duplication, I'd
> > suggest we can instead have a FileType enum and a common get API based on
> > the FileType. What do you think?
> >
> >
> > Cheers,
> > Kowshik
> >
> >
> > On Mon, Dec 14, 2020 at 11:07 AM Satish Duggana <sa...@gmail.com>
> > wrote:
> >
> > > Hi Jun,
> > > Thanks for your comments. Please go through the inline replies.
> > >
> > >
> > > 5102.2: It seems that both positions can just be int. Another option is
> > to
> > > have two methods. Would it be clearer?
> > >
> > >     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> > > remoteLogSegmentMetadata,  int startPosition)
> > throwsRemoteStorageException;
> > >
> > >     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> > > remoteLogSegmentMetadata, int startPosition, int endPosition) throws
> > > RemoteStorageException;
> > >
> > > That makes sense to me, updated the KIP.
> > >
> > > 6003: Could you also update the javadoc for the return value?
> > >
> > > Updated.
> > >
> > > 6020: local.log.retention.bytes: Should it default to log.retention.bytes
> > > to be consistent with local.log.retention.ms?
> > >
> > > Yes, it can be defaulted to log.retention.bytes.
> > >
> > > 6021: Could you define TopicIdPartition?
> > >
> > > Added TopicIdPartition in the KIP.
> > >
> > > 6022: For all public facing classes, could you specify the package name?
> > >
> > > Updated.
> > >
> > >
> > > Thanks,
> > > Satish.
> > >
> > > On Tue, Dec 8, 2020 at 12:59 AM Jun Rao <ju...@confluent.io> wrote:
> > > >
> > > > Hi, Satish,
> > > >
> > > > Thanks for the reply. A few more comments below.
> > > >
> > > > 5102.2: It seems that both positions can just be int. Another option is
> > > to
> > > > have two methods. Would it be clearer?
> > > >
> > > >     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> > > > remoteLogSegmentMetadata,
> > > >                                     int startPosition) throws
> > > > RemoteStorageException;
> > > >
> > > >     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> > > > remoteLogSegmentMetadata,
> > > >                                     int startPosition, int endPosition)
> > > > throws RemoteStorageException;
> > > >
> > > > 6003: Could you also update the javadoc for the return value?
> > > >
> > > > 6010: What kind of tiering throughput have you seen with 5 threads?
> > > >
> > > > 6020: local.log.retention.bytes: Should it default to
> > log.retention.bytes
> > > > to be consistent with local.log.retention.ms?
> > > >
> > > > 6021: Could you define TopicIdPartition?
> > > >
> > > > 6022: For all public facing classes, could you specify the package
> > name?
> > > >
> > > > It seems that you already added the topicId support. Two other
> > remaining
> > > > items are (a) the format of local tier metadata storage and (b)
> > upgrade.
> > > >
> > > > Jun
> > > >
> > > > On Mon, Dec 7, 2020 at 8:56 AM Satish Duggana <
> > satish.duggana@gmail.com>
> > > > wrote:
> > > >
> > > > > Hi Jun,
> > > > > Thanks for your comments. Please find the inline replies below.
> > > > >
> > > > > >605.2 It's rare for the follower to need the remote data. So, the
> > > current
> > > > > approach is fine too. Could you document the process of rebuilding
> > the
> > > > > producer state since we can't simply trim the producerState to an
> > > offset in
> > > > > the middle of a segment.
> > > > >
> > > > > Will clarify in the KIP.
> > > > >
> > > > > >5102.2 Would it be clearer to make startPosiont long and endPosition
> > > of
> > > > > Optional<Long>?
> > > > >
> > > > > We will have arg checks with respective validation. It is not a good
> > > > > practice to have arguments with optional as mentioned here.
> > > > > https://rules.sonarsource.com/java/RSPEC-3553
> > > > >
> > > > >
> > > > > >5102.5 LogSegmentData still has leaderEpochIndex as File instead of
> > > > > ByteBuffer.
> > > > >
> > > > > Updated.
> > > > >
> > > > > >5102.7 Could you define all public methods for LogSegmentData?
> > > > >
> > > > > Updated.
> > > > >
> > > > > >5103.5 Could you change the reference to rlm_process_interval_ms and
> > > > > rlm_retry_interval_ms to the new config names? Also, the retry
> > interval
> > > > > config seems still missing. It would be useful to support exponential
> > > > > backoff with the retry interval config.
> > > > >
> > > > > Good point. We wanted the retry with truncated exponential backoff,
> > > > > updated the KIP.
> > > > >
> > > > > >5111. "RLM follower fetches the earliest offset for the earliest
> > > leader
> > > > > epoch by calling RLMM.earliestLogOffset(TopicPartition
> > topicPartition,
> > > int
> > > > > leaderEpoch) and updates that as the log start offset." This text is
> > > still
> > > > > there. Also, could we remove earliestLogOffset() from RLMM?
> > > > >
> > > > > Updated.
> > > > >
> > > > > >5115. There are still references to "remote log cleaners".
> > > > >
> > > > > Updated.
> > > > >
> > > > > >6000. Since we are returning new error codes, we need to bump up the
> > > > > protocol version for Fetch request. Also, it will be useful to
> > > document all
> > > > > new error codes and whether they are retriable or not.
> > > > >
> > > > > Sure, we will add that in the KIP.
> > > > >
> > > > > >6001. public Map<Long, Long> segmentLeaderEpochs(): Currently,
> > > leaderEpoch
> > > > > is int32 instead of long.
> > > > >
> > > > > Updated.
> > > > >
> > > > > >6002. Is RemoteLogSegmentMetadata.markedForDeletion() needed given
> > > > > RemoteLogSegmentMetadata.state()?
> > > > >
> > > > > No, it is fixed.
> > > > >
> > > > > >6003. RemoteLogSegmentMetadata
> > remoteLogSegmentMetadata(TopicPartition
> > > > > topicPartition, long offset, int epochForOffset): Should this return
> > > > > Optional<RemoteLogSegmentMetadata>?
> > > > >
> > > > > That makes sense, updated.
> > > > >
> > > > > >6005. RemoteLogState: It seems it's better to split it between
> > > > > DeletePartitionUpdate and RemoteLogSegmentMetadataUpdate since the
> > > states
> > > > > are never shared between the two use cases.
> > > > >
> > > > > Agree with that, updated.
> > > > >
> > > > > >6006. RLMM.onPartitionLeadershipChanges(): This may be ok. However,
> > > is it
> > > > > ture that other than the metadata topic, RLMM just needs to know
> > > whether
> > > > > there is a replica assigned to this broker and doesn't need to know
> > > whether
> > > > > the replica is the leader or the follower?
> > > > >
> > > > > That may be true. If the implementation does not need that, it can
> > > > > ignore the information in the callback.
> > > > >
> > > > > >6007: "Handle expired remote segments (leader and follower)": Why is
> > > this
> > > > > needed in both the leader and the follower?
> > > > >
> > > > > Updated.
> > > > >
> > > > > >6008.       "name": "SegmentSizeInBytes",
> > > > >                 "type": "int64",
> > > > > The segment size can just be int32.
> > > > >
> > > > > Updated.
> > > > >
> > > > > >6009. For the record format in the log, it seems that we need to add
> > > > > record
> > > > > type and record version before the serialized bytes. We can follow
> > the
> > > > > convention used in
> > > > >
> > > > >
> > >
> > https://cwiki.apache.org/confluence/display/KAFKA/KIP-631%3A+The+Quorum-based+Kafka+Controller#KIP631:TheQuorumbasedKafkaController-RecordFormats
> > > > >
> > > > > Yes, KIP already mentions that these are serialized before the
> > payload
> > > > > as below. We will mention explicitly that these two are written
> > before
> > > > > the data is written.
> > > > >
> > > > > RLMM instance on broker publishes the message to the topic with key
> > as
> > > > > null and value with the below format.
> > > > >
> > > > > type      : unsigned var int, represents the value type. This value
> > is
> > > > > 'apikey' as mentioned in the schema.
> > > > > version : unsigned var int, the 'version' number of the type as
> > > > > mentioned in the schema.
> > > > > data      : record payload in kafka protocol message format.
> > > > >
> > > > >
> > > > > >6010. remote.log.manager.thread.pool.size: The default value is 10.
> > > This
> > > > > might be too high when enabling the tiered feature for the first
> > time.
> > > > > Since there are lots of segments that need to be tiered initially, a
> > > large
> > > > > number of threads could overwhelm the broker.
> > > > >
> > > > > Is the default value 5 reasonable?
> > > > >
> > > > > 6011. "The number of milli seconds to keep the local log segment
> > > before it
> > > > > gets deleted. If not set, the value in `log.retention.minutes` is
> > > used. If
> > > > > set to -1, no time limit is applied." We should use log.retention.ms
> > > > > instead of log.retention.minutes.
> > > > > Nice typo catch. Updated the KIP.
> > > > >
> > > > > Thanks,
> > > > > Satish.
> > > > >
> > > > > On Thu, Dec 3, 2020 at 8:03 AM Jun Rao <ju...@confluent.io> wrote:
> > > > > >
> > > > > > Hi, Satish,
> > > > > >
> > > > > > Thanks for the updated KIP. A few more comments below.
> > > > > >
> > > > > > 605.2 It's rare for the follower to need the remote data. So, the
> > > current
> > > > > > approach is fine too. Could you document the process of rebuilding
> > > the
> > > > > > producer state since we can't simply trim the producerState to an
> > > offset
> > > > > in
> > > > > > the middle of a segment.
> > > > > >
> > > > > > 5102.2 Would it be clearer to make startPosiont long and
> > endPosition
> > > of
> > > > > > Optional<Long>?
> > > > > >
> > > > > > 5102.5 LogSegmentData still has leaderEpochIndex as File instead of
> > > > > > ByteBuffer.
> > > > > >
> > > > > > 5102.7 Could you define all public methods for LogSegmentData?
> > > > > >
> > > > > > 5103.5 Could you change the reference to rlm_process_interval_ms
> > and
> > > > > > rlm_retry_interval_ms to the new config names? Also, the retry
> > > interval
> > > > > > config seems still missing. It would be useful to support
> > exponential
> > > > > > backoff with the retry interval config.
> > > > > >
> > > > > > 5111. "RLM follower fetches the earliest offset for the earliest
> > > leader
> > > > > > epoch by calling RLMM.earliestLogOffset(TopicPartition
> > > topicPartition,
> > > > > int
> > > > > > leaderEpoch) and updates that as the log start offset." This text
> > is
> > > > > still
> > > > > > there. Also, could we remove earliestLogOffset() from RLMM?
> > > > > >
> > > > > > 5115. There are still references to "remote log cleaners".
> > > > > >
> > > > > > 6000. Since we are returning new error codes, we need to bump up
> > the
> > > > > > protocol version for Fetch request. Also, it will be useful to
> > > document
> > > > > all
> > > > > > new error codes and whether they are retriable or not.
> > > > > >
> > > > > > 6001. public Map<Long, Long> segmentLeaderEpochs(): Currently,
> > > > > leaderEpoch
> > > > > > is int32 instead of long.
> > > > > >
> > > > > > 6002. Is RemoteLogSegmentMetadata.markedForDeletion() needed given
> > > > > > RemoteLogSegmentMetadata.state()?
> > > > > >
> > > > > > 6003. RemoteLogSegmentMetadata
> > > remoteLogSegmentMetadata(TopicPartition
> > > > > > topicPartition, long offset, int epochForOffset): Should this
> > return
> > > > > > Optional<RemoteLogSegmentMetadata>?
> > > > > >
> > > > > > 6004. DeletePartitionUpdate.epoch(): It would be useful to pick a
> > > more
> > > > > > indicative name so that people understand what epoch this is.
> > > > > >
> > > > > > 6005. RemoteLogState: It seems it's better to split it between
> > > > > > DeletePartitionUpdate and RemoteLogSegmentMetadataUpdate since the
> > > states
> > > > > > are never shared between the two use cases.
> > > > > >
> > > > > > 6006. RLMM.onPartitionLeadershipChanges(): This may be ok. However,
> > > is it
> > > > > > ture that other than the metadata topic, RLMM just needs to know
> > > whether
> > > > > > there is a replica assigned to this broker and doesn't need to know
> > > > > whether
> > > > > > the replica is the leader or the follower?
> > > > > >
> > > > > > 6007: "Handle expired remote segments (leader and follower)": Why
> > is
> > > this
> > > > > > needed in both the leader and the follower?
> > > > > >
> > > > > > 6008.       "name": "SegmentSizeInBytes",
> > > > > >                 "type": "int64",
> > > > > > The segment size can just be int32.
> > > > > >
> > > > > > 6009. For the record format in the log, it seems that we need to
> > add
> > > > > record
> > > > > > type and record version before the serialized bytes. We can follow
> > > the
> > > > > > convention used in
> > > > > >
> > > > >
> > >
> > https://cwiki.apache.org/confluence/display/KAFKA/KIP-631%3A+The+Quorum-based+Kafka+Controller#KIP631:TheQuorumbasedKafkaController-RecordFormats
> > > > > > .
> > > > > >
> > > > > > 6010. remote.log.manager.thread.pool.size: The default value is 10.
> > > This
> > > > > > might be too high when enabling the tiered feature for the first
> > > time.
> > > > > > Since there are lots of segments that need to be tiered initially,
> > a
> > > > > large
> > > > > > number of threads could overwhelm the broker.
> > > > > >
> > > > > > 6011. "The number of milli seconds to keep the local log segment
> > > before
> > > > > it
> > > > > > gets deleted. If not set, the value in `log.retention.minutes` is
> > > used.
> > > > > If
> > > > > > set to -1, no time limit is applied." We should use
> > log.retention.ms
> > > > > > instead of log.retention.minutes.
> > > > > >
> > > > > > Jun
> > > > > >
> > > > > > On Tue, Dec 1, 2020 at 2:42 AM Satish Duggana <
> > > satish.duggana@gmail.com>
> > > > > > wrote:
> > > > > >
> > > > > > > Hi,
> > > > > > > We updated the KIP with the points mentioned in the earlier mail
> > > > > > > except for KIP-516 related changes. You can go through them and
> > > let us
> > > > > > > know if you have any comments. We will update the KIP with the
> > > > > > > remaining todo items and KIP-516 related changes by end of this
> > > > > > > week(5th Dec).
> > > > > > >
> > > > > > > Thanks,
> > > > > > > Satish.
> > > > > > >
> > > > > > > On Tue, Nov 10, 2020 at 8:26 PM Satish Duggana <
> > > > > satish.duggana@gmail.com>
> > > > > > > wrote:
> > > > > > > >
> > > > > > > > Hi Jun,
> > > > > > > > Thanks for your comments. Please find the inline replies below.
> > > > > > > >
> > > > > > > > 605.2 "Build the local leader epoch cache by cutting the leader
> > > epoch
> > > > > > > > sequence received from remote storage to [LSO, ELO]." I
> > > mentioned an
> > > > > > > issue
> > > > > > > > earlier. Suppose the leader's local start offset is 100. The
> > > follower
> > > > > > > finds
> > > > > > > > a remote segment covering offset range [80, 120). The
> > > producerState
> > > > > with
> > > > > > > > this remote segment is up to offset 120. To trim the
> > > producerState to
> > > > > > > > offset 100 requires more work since one needs to download the
> > > > > previous
> > > > > > > > producerState up to offset 80 and then replay the messages from
> > > 80 to
> > > > > > > 100.
> > > > > > > > It seems that it's simpler in this case for the follower just
> > to
> > > > > take the
> > > > > > > > remote segment as it is and start fetching from offset 120.
> > > > > > > >
> > > > > > > > We chose that approach to avoid any edge cases here. It may be
> > > > > > > > possible that the remote log segment that is received may not
> > > have
> > > > > the
> > > > > > > > same leader epoch sequence from 100-120 as it contains on the
> > > > > > > > leader(this can happen due to unclean leader). It is safe to
> > > start
> > > > > > > > from what the leader returns here.Another way is to find the
> > > remote
> > > > > > > > log segment
> > > > > > > >
> > > > > > > > 5016. Just to echo what Kowshik was saying. It seems that
> > > > > > > > RLMM.onPartitionLeadershipChanges() is only called on the
> > > replicas
> > > > > for a
> > > > > > > > partition, not on the replicas for the
> > > __remote_log_segment_metadata
> > > > > > > > partition. It's not clear how the leader of
> > > > > __remote_log_segment_metadata
> > > > > > > > obtains the metadata for remote segments for deletion.
> > > > > > > >
> > > > > > > > RLMM will always receive the callback for the remote log
> > metadata
> > > > > > > > topic partitions hosted on the local broker and these will be
> > > > > > > > subscribed. I will make this clear in the KIP.
> > > > > > > >
> > > > > > > > 5100. KIP-516 has been accepted and is being implemented now.
> > > Could
> > > > > you
> > > > > > > > update the KIP based on topicID?
> > > > > > > >
> > > > > > > > We mentioned KIP-516 and how it helps. We will update this KIP
> > > with
> > > > > > > > all the changes it brings with KIP-516.
> > > > > > > >
> > > > > > > > 5101. RLMM: It would be useful to clarify how the following two
> > > APIs
> > > > > are
> > > > > > > > used. According to the wiki, the former is used for topic
> > > deletion
> > > > > and
> > > > > > > the
> > > > > > > > latter is used for retention. It seems that retention should
> > use
> > > the
> > > > > > > former
> > > > > > > > since remote segments without a matching epoch in the leader
> > > > > (potentially
> > > > > > > > due to unclean leader election) also need to be garbage
> > > collected.
> > > > > The
> > > > > > > > latter seems to be used for the new leader to determine the
> > last
> > > > > tiered
> > > > > > > > segment.
> > > > > > > >     default Iterator<RemoteLogSegmentMetadata>
> > > > > > > > listRemoteLogSegments(TopicPartition topicPartition)
> > > > > > > >     Iterator<RemoteLogSegmentMetadata>
> > > > > > > listRemoteLogSegments(TopicPartition
> > > > > > > > topicPartition, long leaderEpoch);
> > > > > > > >
> > > > > > > > Right,.that is what we are currently doing. We will update the
> > > > > > > > javadocs and wiki with that. Earlier, we did not want to remove
> > > the
> > > > > > > > segments which are not matched with leader epochs from the
> > ladder
> > > > > > > > partition as they may be used later by a replica which can
> > > become a
> > > > > > > > leader (unclean leader election) and refer those segments. But
> > > that
> > > > > > > > may leak these segments in remote storage until the topic
> > > lifetime.
> > > > > We
> > > > > > > > decided to cleanup the segments with the oldest incase of size
> > > based
> > > > > > > > retention also.
> > > > > > > >
> > > > > > > > 5102. RSM:
> > > > > > > > 5102.1 For methods like fetchLogSegmentData(), it seems that
> > > they can
> > > > > > > > use RemoteLogSegmentId instead of RemoteLogSegmentMetadata.
> > > > > > > >
> > > > > > > > It will be useful to have metadata for RSM to fetch log
> > segment.
> > > It
> > > > > > > > may create location/path using id with other metadata too.
> > > > > > > >
> > > > > > > > 5102.2 In fetchLogSegmentData(), should we use long instead of
> > > Long?
> > > > > > > >
> > > > > > > > Wanted to keep endPosition as optional to read till the end of
> > > the
> > > > > > > > segment and avoid sentinels.
> > > > > > > >
> > > > > > > > 5102.3 Why only some of the methods have default implementation
> > > and
> > > > > > > others
> > > > > > > > Don't?
> > > > > > > >
> > > > > > > > Actually,  RSM will not have any default implementations.
> > Those 3
> > > > > > > > methods were made default earlier for tests etc. Updated the
> > > wiki.
> > > > > > > >
> > > > > > > > 5102.4. Could we define RemoteLogSegmentMetadataUpdate
> > > > > > > > and DeletePartitionUpdate?
> > > > > > > >
> > > > > > > > Sure, they will be added.
> > > > > > > >
> > > > > > > >
> > > > > > > > 5102.5 LogSegmentData: It seems that it's easier to pass
> > > > > > > > in leaderEpochIndex as a ByteBuffer or byte array than a file
> > > since
> > > > > it
> > > > > > > will
> > > > > > > > be generated in memory.
> > > > > > > >
> > > > > > > > Right, this is in plan.
> > > > > > > >
> > > > > > > > 5102.6 RemoteLogSegmentMetadata: It seems that it needs both
> > > > > baseOffset
> > > > > > > and
> > > > > > > > startOffset. For example, deleteRecords() could move the
> > > startOffset
> > > > > to
> > > > > > > the
> > > > > > > > middle of a segment. If we copy the full segment to remote
> > > storage,
> > > > > the
> > > > > > > > baseOffset and the startOffset will be different.
> > > > > > > >
> > > > > > > > Good point. startOffset is baseOffset by default, if not set
> > > > > explicitly.
> > > > > > > >
> > > > > > > > 5102.7 Could we define all the public methods for
> > > > > > > RemoteLogSegmentMetadata
> > > > > > > > and LogSegmentData?
> > > > > > > >
> > > > > > > > Sure, updated the wiki.
> > > > > > > >
> > > > > > > > 5102.8 Could we document whether endOffset in
> > > > > RemoteLogSegmentMetadata is
> > > > > > > > inclusive/exclusive?
> > > > > > > >
> > > > > > > > It is inclusive, will update.
> > > > > > > >
> > > > > > > > 5103. configs:
> > > > > > > > 5103.1 Could we define the default value of non-required
> > configs
> > > > > (e.g the
> > > > > > > > size of new thread pools)?
> > > > > > > >
> > > > > > > > Sure, that makes sense.
> > > > > > > >
> > > > > > > > 5103.2 It seems that local.log.retention.ms should default to
> > > > > > > retention.ms,
> > > > > > > > instead of remote.log.retention.minutes. Similarly, it seems
> > > > > > > > that local.log.retention.bytes should default to segment.bytes.
> > > > > > > >
> > > > > > > > Right, we do not have  remote.log.retention as we discussed
> > > earlier.
> > > > > > > > Thanks for catching the typo.
> > > > > > > >
> > > > > > > > 5103.3 remote.log.manager.thread.pool.size: The description
> > says
> > > > > "used in
> > > > > > > > scheduling tasks to copy segments, fetch remote log indexes and
> > > > > clean up
> > > > > > > > remote log segments". However, there is a separate
> > > > > > > > config remote.log.reader.threads for fetching remote data. It's
> > > > > weird to
> > > > > > > > fetch remote index and log in different thread pools since both
> > > are
> > > > > used
> > > > > > > > for serving fetch requests.
> > > > > > > >
> > > > > > > > Right, remote.log.manager.thread.pool is mainly used for
> > > copy/cleanup
> > > > > > > > activities. Fetch path always goes through
> > > remote.log.reader.threads.
> > > > > > > >
> > > > > > > > 5103.4 remote.log.manager.task.interval.ms: Is that the amount
> > > of
> > > > > time
> > > > > > > to
> > > > > > > > back off when there is no work to do? If so, perhaps it can be
> > > > > renamed as
> > > > > > > > backoff.ms.
> > > > > > > >
> > > > > > > > This is the delay interval for each iteration. It may be
> > renamed
> > > to
> > > > > > > > remote.log.manager.task.delay.ms
> > > > > > > >
> > > > > > > > 5103.5 Are rlm_process_interval_ms and rlm_retry_interval_ms
> > > > > configs? If
> > > > > > > > so, they need to be listed in this section.
> > > > > > > >
> > > > > > > > remote.log.manager.task.interval.ms is the process internal,
> > > retry
> > > > > > > > interval is missing in the configs, which will be updated in
> > the
> > > KIP.
> > > > > > > >
> > > > > > > > 5104. "RLM maintains a bounded cache(possibly LRU) of the index
> > > > > files of
> > > > > > > > remote log segments to avoid multiple index fetches from the
> > > remote
> > > > > > > > storage." Is the RLM in memory or on disk? If on disk, where is
> > > it
> > > > > > > stored?
> > > > > > > > Do we need a configuration to bound the size?
> > > > > > > >
> > > > > > > > It is stored on disk. They are stored in a directory
> > > > > > > > `remote-log-index-cache` under log dir. We plan to have a
> > config
> > > for
> > > > > > > > that instead of default. We will have a configuration for that.
> > > > > > > >
> > > > > > > > 5105. The KIP uses local-log-start-offset and Earliest Local
> > > Offset
> > > > > in
> > > > > > > > different places. It would be useful to standardize the
> > > terminology.
> > > > > > > >
> > > > > > > > Sure.
> > > > > > > >
> > > > > > > > 5106. The section on "In BuildingRemoteLogAux state". It listed
> > > two
> > > > > > > options
> > > > > > > > without saying which option is chosen.
> > > > > > > > We already mentioned in the KIP that we chose option-2.
> > > > > > > >
> > > > > > > > 5107. Follower to leader transition: It has step 2, but not
> > step
> > > 1.
> > > > > > > > Step-1 is there but it is not explicitly highlighted. It is
> > > previous
> > > > > > > > table to step-2.
> > > > > > > >
> > > > > > > > 5108. If a consumer fetches from the remote data and the remote
> > > > > storage
> > > > > > > is
> > > > > > > > not available, what error code is used in the fetch response?
> > > > > > > >
> > > > > > > > Good point. We have not yet defined the error for this case. We
> > > need
> > > > > > > > to define an error message and send the same in fetch response.
> > > > > > > >
> > > > > > > > 5109. "ListOffsets: For timestamps >= 0, it returns the first
> > > message
> > > > > > > > offset whose timestamp is >= to the given timestamp in the
> > > request.
> > > > > That
> > > > > > > > means it checks in remote log time indexes first, after which
> > > local
> > > > > log
> > > > > > > > time indexes are checked." Could you document which method in
> > > RLMM is
> > > > > > > used
> > > > > > > > for this?
> > > > > > > >
> > > > > > > > Okay.
> > > > > > > >
> > > > > > > > 5110. Stopreplica: "it sets all the remote log segment metadata
> > > of
> > > > > that
> > > > > > > > partition with a delete marker and publishes them to RLMM."
> > This
> > > > > seems
> > > > > > > > outdated given the new topic deletion logic.
> > > > > > > >
> > > > > > > > Will update with KIP-516 related points.
> > > > > > > >
> > > > > > > > 5111. "RLM follower fetches the earliest offset for the
> > earliest
> > > > > leader
> > > > > > > > epoch by calling RLMM.earliestLogOffset(TopicPartition
> > > > > topicPartition,
> > > > > > > int
> > > > > > > > leaderEpoch) and updates that as the log start offset." Do we
> > > need
> > > > > that
> > > > > > > > since replication propagates logStartOffset already?
> > > > > > > >
> > > > > > > > Good point. Right, existing replication protocol takes care of
> > > > > > > > updating the followers’s log start offset received from the
> > > leader.
> > > > > > > >
> > > > > > > > 5112. Is the default maxWaitMs of 500ms enough for fetching
> > from
> > > > > remote
> > > > > > > > storage?
> > > > > > > >
> > > > > > > > Remote reads may fail within the current default wait time, but
> > > > > > > > subsequent fetches would be able to serve as that data is
> > stored
> > > in
> > > > > > > > the local cache. This cache is currently implemented in RSMs.
> > > But we
> > > > > > > > plan to pull this into the remote log messaging layer in
> > future.
> > > > > > > >
> > > > > > > > 5113. "Committed offsets can be stored in a local file to avoid
> > > > > reading
> > > > > > > the
> > > > > > > > messages again when a broker is restarted." Could you describe
> > > the
> > > > > format
> > > > > > > > and the location of the file? Also, could the same message be
> > > > > processed
> > > > > > > by
> > > > > > > > RLMM again after broker restart? If so, how do we handle that?
> > > > > > > >
> > > > > > > > Sure, we will update in the KIP.
> > > > > > > >
> > > > > > > > 5114. Message format
> > > > > > > > 5114.1 There are two records named
> > RemoteLogSegmentMetadataRecord
> > > > > with
> > > > > > > > apiKey 0 and 1.
> > > > > > > >
> > > > > > > > Nice catch, that was a typo. Fixed in the wiki.
> > > > > > > >
> > > > > > > > 5114.2 RemoteLogSegmentMetadataRecord: Could we document
> > whether
> > > > > > > endOffset
> > > > > > > > is inclusive/exclusive?
> > > > > > > > It is inclusive, will update.
> > > > > > > >
> > > > > > > > 5114.3 RemoteLogSegmentMetadataRecord: Could you explain
> > > LeaderEpoch
> > > > > a
> > > > > > > bit
> > > > > > > > more? Is that the epoch of the leader when it copies the
> > segment
> > > to
> > > > > > > remote
> > > > > > > > storage? Also, how will this field be used?
> > > > > > > >
> > > > > > > > Right, this is the leader epoch of the broker which copied this
> > > > > > > > segment. This is helpful in reason about which broker copied
> > the
> > > > > > > > segment to remote storage.
> > > > > > > >
> > > > > > > > 5114.4 EventTimestamp: Could you explain this a bit more? Each
> > > > > record in
> > > > > > > > Kafka already has a timestamp field. Could we just use that?
> > > > > > > >
> > > > > > > > This is the  timestamp at which  the respective event occurred.
> > > Added
> > > > > > > > this  to RemoteLogSegmentMetadata as RLMM can be  any other
> > > > > > > > implementation. We thought about that but it looked cleaner to
> > > use at
> > > > > > > > the message structure level instead of getting that from the
> > > consumer
> > > > > > > > record and using that to build the respective event.
> > > > > > > >
> > > > > > > >
> > > > > > > > 5114.5 SegmentSizeInBytes: Could this just be int32?
> > > > > > > >
> > > > > > > > Right, it looks like config allows only int value >= 14.
> > > > > > > >
> > > > > > > > 5115. RemoteLogCleaner(RLC): This could be confused with the
> > log
> > > > > cleaner
> > > > > > > > for compaction. Perhaps it can be renamed to sth like
> > > > > > > > RemotePartitionRemover.
> > > > > > > >
> > > > > > > > I am fine with RemotePartitionRemover or
> > > RemoteLogDeletionManager(we
> > > > > > > > have other manager classes like RLM, RLMM).
> > > > > > > >
> > > > > > > > 5116. "RLC receives the delete_partition_marked and processes
> > it
> > > if
> > > > > it is
> > > > > > > > not yet processed earlier." How does it know whether
> > > > > > > > delete_partition_marked has been processed earlier?
> > > > > > > >
> > > > > > > > This is to handle duplicate delete_partition_marked events. RLC
> > > > > > > > internally maintains a state for the delete_partition events
> > and
> > > if
> > > > > it
> > > > > > > > already has an existing event then it ignores if it is already
> > > being
> > > > > > > > processed.
> > > > > > > >
> > > > > > > > 5117. Should we add a new MessageFormatter to read the tier
> > > metadata
> > > > > > > topic?
> > > > > > > >
> > > > > > > > Right, this is in plan but did not mention it in the KIP. This
> > > will
> > > > > be
> > > > > > > > useful for debugging purposes too.
> > > > > > > >
> > > > > > > > 5118. "Maximum remote log reader thread pool task queue size.
> > If
> > > the
> > > > > task
> > > > > > > > queue is full, broker will stop reading remote log segments."
> > > What
> > > > > do we
> > > > > > > > return to the fetch request in this case?
> > > > > > > >
> > > > > > > > We return an error response for that partition.
> > > > > > > >
> > > > > > > > 5119. It would be useful to list all things not supported in
> > the
> > > > > first
> > > > > > > > version in a Future work or Limitations section. For example,
> > > > > compacted
> > > > > > > > topic, JBOD, changing remote.log.storage.enable from true to
> > > false,
> > > > > etc.
> > > > > > > >
> > > > > > > > We already have a non-goals section which is filled with some
> > of
> > > > > these
> > > > > > > > details. Do we need another limitations section?
> > > > > > > >
> > > > > > > > Thanks,
> > > > > > > > Satish.
> > > > > > > >
> > > > > > > > On Wed, Nov 4, 2020 at 11:27 PM Jun Rao <ju...@confluent.io>
> > > wrote:
> > > > > > > > >
> > > > > > > > > Hi, Satish,
> > > > > > > > >
> > > > > > > > > Thanks for the updated KIP. A few more comments below.
> > > > > > > > >
> > > > > > > > > 605.2 "Build the local leader epoch cache by cutting the
> > leader
> > > > > epoch
> > > > > > > > > sequence received from remote storage to [LSO, ELO]." I
> > > mentioned
> > > > > an
> > > > > > > issue
> > > > > > > > > earlier. Suppose the leader's local start offset is 100. The
> > > > > follower
> > > > > > > finds
> > > > > > > > > a remote segment covering offset range [80, 120). The
> > > producerState
> > > > > > > with
> > > > > > > > > this remote segment is up to offset 120. To trim the
> > > producerState
> > > > > to
> > > > > > > > > offset 100 requires more work since one needs to download the
> > > > > previous
> > > > > > > > > producerState up to offset 80 and then replay the messages
> > > from 80
> > > > > to
> > > > > > > 100.
> > > > > > > > > It seems that it's simpler in this case for the follower just
> > > to
> > > > > take
> > > > > > > the
> > > > > > > > > remote segment as it is and start fetching from offset 120.
> > > > > > > > >
> > > > > > > > > 5016. Just to echo what Kowshik was saying. It seems that
> > > > > > > > > RLMM.onPartitionLeadershipChanges() is only called on the
> > > replicas
> > > > > for
> > > > > > > a
> > > > > > > > > partition, not on the replicas for the
> > > > > __remote_log_segment_metadata
> > > > > > > > > partition. It's not clear how the leader of
> > > > > > > __remote_log_segment_metadata
> > > > > > > > > obtains the metadata for remote segments for deletion.
> > > > > > > > >
> > > > > > > > > 5100. KIP-516 has been accepted and is being implemented now.
> > > > > Could you
> > > > > > > > > update the KIP based on topicID?
> > > > > > > > >
> > > > > > > > > 5101. RLMM: It would be useful to clarify how the following
> > two
> > > > > APIs
> > > > > > > are
> > > > > > > > > used. According to the wiki, the former is used for topic
> > > deletion
> > > > > and
> > > > > > > the
> > > > > > > > > latter is used for retention. It seems that retention should
> > > use
> > > > > the
> > > > > > > former
> > > > > > > > > since remote segments without a matching epoch in the leader
> > > > > > > (potentially
> > > > > > > > > due to unclean leader election) also need to be garbage
> > > collected.
> > > > > The
> > > > > > > > > latter seems to be used for the new leader to determine the
> > > last
> > > > > tiered
> > > > > > > > > segment.
> > > > > > > > >     default Iterator<RemoteLogSegmentMetadata>
> > > > > > > > > listRemoteLogSegments(TopicPartition topicPartition)
> > > > > > > > >     Iterator<RemoteLogSegmentMetadata>
> > > > > > > listRemoteLogSegments(TopicPartition
> > > > > > > > > topicPartition, long leaderEpoch);
> > > > > > > > >
> > > > > > > > > 5102. RSM:
> > > > > > > > > 5102.1 For methods like fetchLogSegmentData(), it seems that
> > > they
> > > > > can
> > > > > > > > > use RemoteLogSegmentId instead of RemoteLogSegmentMetadata.
> > > > > > > > > 5102.2 In fetchLogSegmentData(), should we use long instead
> > of
> > > > > Long?
> > > > > > > > > 5102.3 Why only some of the methods have default
> > > implementation and
> > > > > > > others
> > > > > > > > > don't?
> > > > > > > > > 5102.4. Could we define RemoteLogSegmentMetadataUpdate
> > > > > > > > > and DeletePartitionUpdate?
> > > > > > > > > 5102.5 LogSegmentData: It seems that it's easier to pass
> > > > > > > > > in leaderEpochIndex as a ByteBuffer or byte array than a file
> > > > > since it
> > > > > > > will
> > > > > > > > > be generated in memory.
> > > > > > > > > 5102.6 RemoteLogSegmentMetadata: It seems that it needs both
> > > > > > > baseOffset and
> > > > > > > > > startOffset. For example, deleteRecords() could move the
> > > > > startOffset
> > > > > > > to the
> > > > > > > > > middle of a segment. If we copy the full segment to remote
> > > > > storage, the
> > > > > > > > > baseOffset and the startOffset will be different.
> > > > > > > > > 5102.7 Could we define all the public methods for
> > > > > > > RemoteLogSegmentMetadata
> > > > > > > > > and LogSegmentData?
> > > > > > > > > 5102.8 Could we document whether endOffset in
> > > > > RemoteLogSegmentMetadata
> > > > > > > is
> > > > > > > > > inclusive/exclusive?
> > > > > > > > >
> > > > > > > > > 5103. configs:
> > > > > > > > > 5103.1 Could we define the default value of non-required
> > > configs
> > > > > (e.g
> > > > > > > the
> > > > > > > > > size of new thread pools)?
> > > > > > > > > 5103.2 It seems that local.log.retention.ms should default
> > to
> > > > > > > retention.ms,
> > > > > > > > > instead of remote.log.retention.minutes. Similarly, it seems
> > > > > > > > > that local.log.retention.bytes should default to
> > segment.bytes.
> > > > > > > > > 5103.3 remote.log.manager.thread.pool.size: The description
> > > says
> > > > > "used
> > > > > > > in
> > > > > > > > > scheduling tasks to copy segments, fetch remote log indexes
> > and
> > > > > clean
> > > > > > > up
> > > > > > > > > remote log segments". However, there is a separate
> > > > > > > > > config remote.log.reader.threads for fetching remote data.
> > It's
> > > > > weird
> > > > > > > to
> > > > > > > > > fetch remote index and log in different thread pools since
> > > both are
> > > > > > > used
> > > > > > > > > for serving fetch requests.
> > > > > > > > > 5103.4 remote.log.manager.task.interval.ms: Is that the
> > > amount of
> > > > > > > time to
> > > > > > > > > back off when there is no work to do? If so, perhaps it can
> > be
> > > > > renamed
> > > > > > > as
> > > > > > > > > backoff.ms.
> > > > > > > > > 5103.5 Are rlm_process_interval_ms and rlm_retry_interval_ms
> > > > > configs?
> > > > > > > If
> > > > > > > > > so, they need to be listed in this section.
> > > > > > > > >
> > > > > > > > > 5104. "RLM maintains a bounded cache(possibly LRU) of the
> > index
> > > > > files
> > > > > > > of
> > > > > > > > > remote log segments to avoid multiple index fetches from the
> > > remote
> > > > > > > > > storage." Is the RLM in memory or on disk? If on disk, where
> > > is it
> > > > > > > stored?
> > > > > > > > > Do we need a configuration to bound the size?
> > > > > > > > >
> > > > > > > > > 5105. The KIP uses local-log-start-offset and Earliest Local
> > > > > Offset in
> > > > > > > > > different places. It would be useful to standardize the
> > > > > terminology.
> > > > > > > > >
> > > > > > > > > 5106. The section on "In BuildingRemoteLogAux state". It
> > > listed two
> > > > > > > options
> > > > > > > > > without saying which option is chosen.
> > > > > > > > >
> > > > > > > > > 5107. Follower to leader transition: It has step 2, but not
> > > step 1.
> > > > > > > > >
> > > > > > > > > 5108. If a consumer fetches from the remote data and the
> > remote
> > > > > > > storage is
> > > > > > > > > not available, what error code is used in the fetch response?
> > > > > > > > >
> > > > > > > > > 5109. "ListOffsets: For timestamps >= 0, it returns the first
> > > > > message
> > > > > > > > > offset whose timestamp is >= to the given timestamp in the
> > > request.
> > > > > > > That
> > > > > > > > > means it checks in remote log time indexes first, after which
> > > > > local log
> > > > > > > > > time indexes are checked." Could you document which method in
> > > RLMM
> > > > > is
> > > > > > > used
> > > > > > > > > for this?
> > > > > > > > >
> > > > > > > > > 5110. Stopreplica: "it sets all the remote log segment
> > > metadata of
> > > > > that
> > > > > > > > > partition with a delete marker and publishes them to RLMM."
> > > This
> > > > > seems
> > > > > > > > > outdated given the new topic deletion logic.
> > > > > > > > >
> > > > > > > > > 5111. "RLM follower fetches the earliest offset for the
> > > earliest
> > > > > leader
> > > > > > > > > epoch by calling RLMM.earliestLogOffset(TopicPartition
> > > > > topicPartition,
> > > > > > > int
> > > > > > > > > leaderEpoch) and updates that as the log start offset." Do we
> > > need
> > > > > that
> > > > > > > > > since replication propagates logStartOffset already?
> > > > > > > > >
> > > > > > > > > 5112. Is the default maxWaitMs of 500ms enough for fetching
> > > from
> > > > > remote
> > > > > > > > > storage?
> > > > > > > > >
> > > > > > > > > 5113. "Committed offsets can be stored in a local file to
> > avoid
> > > > > > > reading the
> > > > > > > > > messages again when a broker is restarted." Could you
> > describe
> > > the
> > > > > > > format
> > > > > > > > > and the location of the file? Also, could the same message be
> > > > > > > processed by
> > > > > > > > > RLMM again after broker restart? If so, how do we handle
> > that?
> > > > > > > > >
> > > > > > > > > 5114. Message format
> > > > > > > > > 5114.1 There are two records named
> > > RemoteLogSegmentMetadataRecord
> > > > > with
> > > > > > > > > apiKey 0 and 1.
> > > > > > > > > 5114.2 RemoteLogSegmentMetadataRecord: Could we document
> > > whether
> > > > > > > endOffset
> > > > > > > > > is inclusive/exclusive?
> > > > > > > > > 5114.3 RemoteLogSegmentMetadataRecord: Could you explain
> > > > > LeaderEpoch a
> > > > > > > bit
> > > > > > > > > more? Is that the epoch of the leader when it copies the
> > > segment to
> > > > > > > remote
> > > > > > > > > storage? Also, how will this field be used?
> > > > > > > > > 5114.4 EventTimestamp: Could you explain this a bit more?
> > Each
> > > > > record
> > > > > > > in
> > > > > > > > > Kafka already has a timestamp field. Could we just use that?
> > > > > > > > > 5114.5 SegmentSizeInBytes: Could this just be int32?
> > > > > > > > >
> > > > > > > > > 5115. RemoteLogCleaner(RLC): This could be confused with the
> > > log
> > > > > > > cleaner
> > > > > > > > > for compaction. Perhaps it can be renamed to sth like
> > > > > > > > > RemotePartitionRemover.
> > > > > > > > >
> > > > > > > > > 5116. "RLC receives the delete_partition_marked and processes
> > > it
> > > > > if it
> > > > > > > is
> > > > > > > > > not yet processed earlier." How does it know whether
> > > > > > > > > delete_partition_marked has been processed earlier?
> > > > > > > > >
> > > > > > > > > 5117. Should we add a new MessageFormatter to read the tier
> > > > > metadata
> > > > > > > topic?
> > > > > > > > >
> > > > > > > > > 5118. "Maximum remote log reader thread pool task queue size.
> > > If
> > > > > the
> > > > > > > task
> > > > > > > > > queue is full, broker will stop reading remote log segments."
> > > What
> > > > > do
> > > > > > > we
> > > > > > > > > return to the fetch request in this case?
> > > > > > > > >
> > > > > > > > > 5119. It would be useful to list all things not supported in
> > > the
> > > > > first
> > > > > > > > > version in a Future work or Limitations section. For example,
> > > > > compacted
> > > > > > > > > topic, JBOD, changing remote.log.storage.enable from true to
> > > false,
> > > > > > > etc.
> > > > > > > > >
> > > > > > > > > Thanks,
> > > > > > > > >
> > > > > > > > > Jun
> > > > > > > > >
> > > > > > > > > On Tue, Oct 27, 2020 at 5:57 PM Kowshik Prakasam <
> > > > > > > kprakasam@confluent.io>
> > > > > > > > > wrote:
> > > > > > > > >
> > > > > > > > > > Hi Satish,
> > > > > > > > > >
> > > > > > > > > > Thanks for the updates to the KIP. Here are my first batch
> > of
> > > > > > > > > > comments/suggestions on the latest version of the KIP.
> > > > > > > > > >
> > > > > > > > > > 5012. In the RemoteStorageManager interface, there is an
> > API
> > > > > defined
> > > > > > > for
> > > > > > > > > > each file type. For example, fetchOffsetIndex,
> > > > > fetchTimestampIndex
> > > > > > > etc. To
> > > > > > > > > > avoid the duplication, I'd suggest we can instead have a
> > > FileType
> > > > > > > enum and
> > > > > > > > > > a common get API based on the FileType.
> > > > > > > > > >
> > > > > > > > > > 5013. There are some references to the Google doc in the
> > > KIP. I
> > > > > > > wasn't sure
> > > > > > > > > > if the Google doc is expected to be in sync with the
> > > contents of
> > > > > the
> > > > > > > wiki.
> > > > > > > > > > Going forward, it seems easier if just the KIP is
> > maintained
> > > as
> > > > > the
> > > > > > > source
> > > > > > > > > > of truth. In this regard, could you please move all the
> > > > > references
> > > > > > > to the
> > > > > > > > > > Google doc, maybe to a separate References section at the
> > > bottom
> > > > > of
> > > > > > > the
> > > > > > > > > > KIP?
> > > > > > > > > >
> > > > > > > > > > 5014. There are some TODO sections in the KIP. Would these
> > be
> > > > > filled
> > > > > > > up in
> > > > > > > > > > future iterations?
> > > > > > > > > >
> > > > > > > > > > 5015. Under "Topic deletion lifecycle", I'm trying to
> > > understand
> > > > > why
> > > > > > > do we
> > > > > > > > > > need delete_partition_marked as well as the
> > > > > delete_partition_started
> > > > > > > > > > messages. I couldn't spot a drawback if supposing we
> > > simplified
> > > > > the
> > > > > > > design
> > > > > > > > > > such that the controller would only write
> > > > > delete_partition_started
> > > > > > > message,
> > > > > > > > > > and RemoteLogCleaner (RLC) instance picks it up for
> > > processing.
> > > > > What
> > > > > > > am I
> > > > > > > > > > missing?
> > > > > > > > > >
> > > > > > > > > > 5016. Under "Topic deletion lifecycle", step (4) is
> > > mentioned as
> > > > > > > "RLC gets
> > > > > > > > > > all the remote log segments for the partition and each of
> > > these
> > > > > > > remote log
> > > > > > > > > > segments is deleted with the next steps.". Since the RLC
> > > instance
> > > > > > > runs on
> > > > > > > > > > each tier topic partition leader, how does the RLC then get
> > > the
> > > > > list
> > > > > > > of
> > > > > > > > > > remote log segments to be deleted? It will be useful to add
> > > that
> > > > > > > detail to
> > > > > > > > > > the KIP.
> > > > > > > > > >
> > > > > > > > > > 5017. Under "Public Interfaces -> Configs", there is a line
> > > > > > > mentioning "We
> > > > > > > > > > will support flipping remote.log.storage.enable in next
> > > > > versions."
> > > > > > > It will
> > > > > > > > > > be useful to mention this in the "Future Work" section of
> > > the KIP
> > > > > > > too.
> > > > > > > > > >
> > > > > > > > > > 5018. The KIP introduces a number of configuration
> > > parameters. It
> > > > > > > will be
> > > > > > > > > > useful to mention in the KIP if the user should assume
> > these
> > > as
> > > > > > > static
> > > > > > > > > > configuration in the server.properties file, or dynamic
> > > > > > > configuration which
> > > > > > > > > > can be modified without restarting the broker.
> > > > > > > > > >
> > > > > > > > > > 5019.  Maybe this is planned as a future update to the KIP,
> > > but I
> > > > > > > thought
> > > > > > > > > > I'd mention it here. Could you please add details to the
> > KIP
> > > on
> > > > > why
> > > > > > > RocksDB
> > > > > > > > > > was chosen as the default cache implementation of RLMM, and
> > > how
> > > > > it
> > > > > > > is going
> > > > > > > > > > to be used? Were alternatives compared/considered? For
> > > example,
> > > > > it
> > > > > > > would be
> > > > > > > > > > useful to explain/evaluate the following: 1) debuggability
> > > of the
> > > > > > > RocksDB
> > > > > > > > > > JNI interface, 2) performance, 3) portability across
> > > platforms
> > > > > and 4)
> > > > > > > > > > interface parity of RocksDB’s JNI api with it's underlying
> > > C/C++
> > > > > api.
> > > > > > > > > >
> > > > > > > > > > 5020. Following up on (5019), for the RocksDB cache, it
> > will
> > > be
> > > > > > > useful to
> > > > > > > > > > explain the relationship/mapping between the following in
> > the
> > > > > KIP:
> > > > > > > 1) # of
> > > > > > > > > > tiered partitions, 2) # of partitions of metadata topic
> > > > > > > > > > __remote_log_metadata and 3) # of RocksDB instances. i.e.
> > is
> > > the
> > > > > > > plan to
> > > > > > > > > > have a RocksDB instance per tiered partition, or per
> > metadata
> > > > > topic
> > > > > > > > > > partition, or just 1 for per broker?
> > > > > > > > > >
> > > > > > > > > > 5021. I was looking at the implementation prototype (PR
> > link:
> > > > > > > > > > https://github.com/apache/kafka/pull/7561). It seems that
> > a
> > > > > boolean
> > > > > > > > > > attribute is being introduced into the Log layer to check
> > if
> > > > > remote
> > > > > > > log
> > > > > > > > > > capability is enabled. While the boolean footprint is small
> > > at
> > > > > the
> > > > > > > moment,
> > > > > > > > > > this can easily grow in the future and become harder to
> > > > > > > > > > test/maintain, considering that the Log layer is already
> > > pretty
> > > > > > > complex. We
> > > > > > > > > > should start thinking about how to manage such changes to
> > > the Log
> > > > > > > layer
> > > > > > > > > > (for the purpose of improved testability, better separation
> > > of
> > > > > > > concerns and
> > > > > > > > > > readability). One proposal I have is to take a step back
> > and
> > > > > define a
> > > > > > > > > > higher level Log interface. Then, the Broker code can be
> > > changed
> > > > > to
> > > > > > > use
> > > > > > > > > > this interface. It can be changed such that only a handle
> > to
> > > the
> > > > > > > interface
> > > > > > > > > > is exposed to other components (such as LogCleaner,
> > > > > ReplicaManager
> > > > > > > etc.)
> > > > > > > > > > and not the underlying Log object. This approach keeps the
> > > user
> > > > > of
> > > > > > > the Log
> > > > > > > > > > layer agnostic of the whereabouts of the data. Underneath
> > the
> > > > > > > interface,
> > > > > > > > > > the implementing classes can completely separate local log
> > > > > > > capabilities
> > > > > > > > > > from the remote log. For example, the Log class can be
> > > > > simplified to
> > > > > > > only
> > > > > > > > > > manage logic surrounding local log segments and metadata.
> > > > > > > Additionally, a
> > > > > > > > > > wrapper class can be provided (implementing the higher
> > level
> > > Log
> > > > > > > interface)
> > > > > > > > > > which will contain any/all logic surrounding tiered data.
> > The
> > > > > wrapper
> > > > > > > > > > class will wrap around an instance of the Log class
> > > delegating
> > > > > the
> > > > > > > local
> > > > > > > > > > log logic to it. Finally, a handle to the wrapper class can
> > > be
> > > > > > > exposed to
> > > > > > > > > > the other components wherever they need a handle to the
> > > higher
> > > > > level
> > > > > > > Log
> > > > > > > > > > interface.
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > Cheers,
> > > > > > > > > > Kowshik
> > > > > > > > > >
> > > > > > > > > > On Mon, Oct 26, 2020 at 9:52 PM Satish Duggana <
> > > > > > > satish.duggana@gmail.com>
> > > > > > > > > > wrote:
> > > > > > > > > >
> > > > > > > > > > > Hi,
> > > > > > > > > > > KIP is updated with 1) topic deletion lifecycle and its
> > > related
> > > > > > > items
> > > > > > > > > > > 2) Protocol changes(mainly related to ListOffsets) and
> > > other
> > > > > minor
> > > > > > > > > > > changes.
> > > > > > > > > > > Please go through them and let us know your comments.
> > > > > > > > > > >
> > > > > > > > > > > Thanks,
> > > > > > > > > > > Satish.
> > > > > > > > > > >
> > > > > > > > > > > On Mon, Sep 28, 2020 at 9:10 PM Satish Duggana <
> > > > > > > satish.duggana@gmail.com
> > > > > > > > > > >
> > > > > > > > > > > wrote:
> > > > > > > > > > > >
> > > > > > > > > > > > Hi Dhruvil,
> > > > > > > > > > > > Thanks for looking into the KIP and sending your
> > > comments.
> > > > > Sorry
> > > > > > > for
> > > > > > > > > > > > the late reply, missed it in the mail thread.
> > > > > > > > > > > >
> > > > > > > > > > > > 1. Could you describe how retention would work with
> > this
> > > KIP
> > > > > and
> > > > > > > which
> > > > > > > > > > > > threads are responsible for driving this work? I
> > believe
> > > > > there
> > > > > > > are 3
> > > > > > > > > > > kinds
> > > > > > > > > > > > of retention processes we are looking at:
> > > > > > > > > > > >   (a) Regular retention for data in tiered storage as
> > per
> > > > > > > configured `
> > > > > > > > > > > > retention.ms` / `retention.bytes`.
> > > > > > > > > > > >   (b) Local retention for data in local storage as per
> > > > > > > configured `
> > > > > > > > > > > > local.log.retention.ms` / `local.log.retention.bytes`
> > > > > > > > > > > >   (c) Possibly regular retention for data in local
> > > storage,
> > > > > if
> > > > > > > the
> > > > > > > > > > > tiering
> > > > > > > > > > > > task is lagging or for data that is below the log start
> > > > > offset.
> > > > > > > > > > > >
> > > > > > > > > > > > Local log retention is done by the existing log cleanup
> > > > > tasks.
> > > > > > > These
> > > > > > > > > > > > are not done for segments that are not yet copied to
> > > remote
> > > > > > > storage.
> > > > > > > > > > > > Remote log cleanup is done by the leader partition’s
> > > RLMTask.
> > > > > > > > > > > >
> > > > > > > > > > > > 2. When does a segment become eligible to be tiered? Is
> > > it as
> > > > > > > soon as
> > > > > > > > > > the
> > > > > > > > > > > > segment is rolled and the end offset is less than the
> > > last
> > > > > stable
> > > > > > > > > > offset
> > > > > > > > > > > as
> > > > > > > > > > > > mentioned in the KIP? I wonder if we need to consider
> > > other
> > > > > > > parameters
> > > > > > > > > > > too,
> > > > > > > > > > > > like the highwatermark so that we are guaranteed that
> > > what
> > > > > we are
> > > > > > > > > > tiering
> > > > > > > > > > > > has been committed to the log and accepted by the ISR.
> > > > > > > > > > > >
> > > > > > > > > > > > AFAIK, last stable offset is always <= highwatermark.
> > > This
> > > > > will
> > > > > > > make
> > > > > > > > > > > > sure we are always tiering the message segments which
> > > have
> > > > > been
> > > > > > > > > > > > accepted by ISR and transactionally completed.
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > 3. The section on "Follower Fetch Scenarios" is useful
> > > but
> > > > > is a
> > > > > > > bit
> > > > > > > > > > > > difficult to parse at the moment. It would be useful to
> > > > > > > summarize the
> > > > > > > > > > > > changes we need in the ReplicaFetcher.
> > > > > > > > > > > >
> > > > > > > > > > > > It may become difficult for users to read/follow if we
> > > add
> > > > > code
> > > > > > > changes
> > > > > > > > > > > here.
> > > > > > > > > > > >
> > > > > > > > > > > > 4. Related to the above, it's a bit unclear how we are
> > > > > planning
> > > > > > > on
> > > > > > > > > > > > restoring the producer state for a new replica. Could
> > you
> > > > > expand
> > > > > > > on
> > > > > > > > > > that?
> > > > > > > > > > > >
> > > > > > > > > > > > It is mentioned in the KIP BuildingRemoteLogAuxState is
> > > > > > > introduced to
> > > > > > > > > > > > build the state like leader epoch sequence and producer
> > > > > snapshots
> > > > > > > > > > > > before it starts fetching the data from the leader. We
> > > will
> > > > > make
> > > > > > > it
> > > > > > > > > > > > clear in the KIP.
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > 5. Similarly, it would be worth summarizing the
> > behavior
> > > on
> > > > > > > unclean
> > > > > > > > > > > leader
> > > > > > > > > > > > election. There are several scenarios to consider here:
> > > data
> > > > > > > loss from
> > > > > > > > > > > > local log, data loss from remote log, data loss from
> > > metadata
> > > > > > > topic,
> > > > > > > > > > etc.
> > > > > > > > > > > > It's worth describing these in detail.
> > > > > > > > > > > >
> > > > > > > > > > > > We mentioned the cases about unclean leader election in
> > > the
> > > > > > > follower
> > > > > > > > > > > > fetch scenarios.
> > > > > > > > > > > > If there are errors while fetching data from remote
> > > store or
> > > > > > > metadata
> > > > > > > > > > > > store, it will work the same way as it works with local
> > > log.
> > > > > It
> > > > > > > > > > > > returns the error back to the caller. Please let us
> > know
> > > if
> > > > > I am
> > > > > > > > > > > > missing your point here.
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > 7. For a READ_COMMITTED FetchRequest, how do we
> > retrieve
> > > and
> > > > > > > return the
> > > > > > > > > > > > aborted transaction metadata?
> > > > > > > > > > > >
> > > > > > > > > > > > When a fetch for a remote log is accessed, we will
> > fetch
> > > > > aborted
> > > > > > > > > > > > transactions along with the segment if it is not found
> > > in the
> > > > > > > local
> > > > > > > > > > > > index cache. This includes the case of transaction
> > index
> > > not
> > > > > > > existing
> > > > > > > > > > > > in the remote log segment. That means, the cache entry
> > > can be
> > > > > > > empty or
> > > > > > > > > > > > have a list of aborted transactions.
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > 8. The `LogSegmentData` class assumes that we have a
> > log
> > > > > segment,
> > > > > > > > > > offset
> > > > > > > > > > > > index, time index, transaction index, producer snapshot
> > > and
> > > > > > > leader
> > > > > > > > > > epoch
> > > > > > > > > > > > index. How do we deal with cases where we do not have
> > > one or
> > > > > > > more of
> > > > > > > > > > > these?
> > > > > > > > > > > > For example, we may not have a transaction index or
> > > producer
> > > > > > > snapshot
> > > > > > > > > > > for a
> > > > > > > > > > > > particular segment. The former is optional, and the
> > > latter is
> > > > > > > only kept
> > > > > > > > > > > for
> > > > > > > > > > > > up to the 3 latest segments.
> > > > > > > > > > > >
> > > > > > > > > > > > This is a good point,  we discussed this in the last
> > > meeting.
> > > > > > > > > > > > Transaction index is optional and we will copy them
> > only
> > > if
> > > > > it
> > > > > > > exists.
> > > > > > > > > > > > We want to keep all the producer snapshots at each log
> > > > > segment
> > > > > > > rolling
> > > > > > > > > > > > and they can be removed if the log copying is
> > successful
> > > and
> > > > > it
> > > > > > > still
> > > > > > > > > > > > maintains the existing latest 3 segments, We only
> > delete
> > > the
> > > > > > > producer
> > > > > > > > > > > > snapshots which have been copied to remote log segments
> > > on
> > > > > > > leader.
> > > > > > > > > > > > Follower will keep the log segments beyond the segments
> > > which
> > > > > > > have not
> > > > > > > > > > > > been copied to remote storage. We will update the KIP
> > > with
> > > > > these
> > > > > > > > > > > > details.
> > > > > > > > > > > >
> > > > > > > > > > > > Thanks,
> > > > > > > > > > > > Satish.
> > > > > > > > > > > >
> > > > > > > > > > > > On Thu, Sep 17, 2020 at 1:47 AM Dhruvil Shah <
> > > > > > > dhruvil@confluent.io>
> > > > > > > > > > > wrote:
> > > > > > > > > > > > >
> > > > > > > > > > > > > Hi Satish, Harsha,
> > > > > > > > > > > > >
> > > > > > > > > > > > > Thanks for the KIP. Few questions below:
> > > > > > > > > > > > >
> > > > > > > > > > > > > 1. Could you describe how retention would work with
> > > this
> > > > > KIP
> > > > > > > and
> > > > > > > > > > which
> > > > > > > > > > > > > threads are responsible for driving this work? I
> > > believe
> > > > > there
> > > > > > > are 3
> > > > > > > > > > > kinds
> > > > > > > > > > > > > of retention processes we are looking at:
> > > > > > > > > > > > >   (a) Regular retention for data in tiered storage as
> > > per
> > > > > > > configured
> > > > > > > > > > `
> > > > > > > > > > > > > retention.ms` / `retention.bytes`.
> > > > > > > > > > > > >   (b) Local retention for data in local storage as
> > per
> > > > > > > configured `
> > > > > > > > > > > > > local.log.retention.ms` /
> > `local.log.retention.bytes`
> > > > > > > > > > > > >   (c) Possibly regular retention for data in local
> > > > > storage, if
> > > > > > > the
> > > > > > > > > > > tiering
> > > > > > > > > > > > > task is lagging or for data that is below the log
> > start
> > > > > offset.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 2. When does a segment become eligible to be tiered?
> > > Is it
> > > > > as
> > > > > > > soon as
> > > > > > > > > > > the
> > > > > > > > > > > > > segment is rolled and the end offset is less than the
> > > last
> > > > > > > stable
> > > > > > > > > > > offset as
> > > > > > > > > > > > > mentioned in the KIP? I wonder if we need to consider
> > > other
> > > > > > > > > > parameters
> > > > > > > > > > > too,
> > > > > > > > > > > > > like the highwatermark so that we are guaranteed that
> > > what
> > > > > we
> > > > > > > are
> > > > > > > > > > > tiering
> > > > > > > > > > > > > has been committed to the log and accepted by the
> > ISR.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 3. The section on "Follower Fetch Scenarios" is
> > useful
> > > but
> > > > > is
> > > > > > > a bit
> > > > > > > > > > > > > difficult to parse at the moment. It would be useful
> > to
> > > > > > > summarize the
> > > > > > > > > > > > > changes we need in the ReplicaFetcher.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 4. Related to the above, it's a bit unclear how we
> > are
> > > > > > > planning on
> > > > > > > > > > > > > restoring the producer state for a new replica. Could
> > > you
> > > > > > > expand on
> > > > > > > > > > > that?
> > > > > > > > > > > > >
> > > > > > > > > > > > > 5. Similarly, it would be worth summarizing the
> > > behavior on
> > > > > > > unclean
> > > > > > > > > > > leader
> > > > > > > > > > > > > election. There are several scenarios to consider
> > here:
> > > > > data
> > > > > > > loss
> > > > > > > > > > from
> > > > > > > > > > > > > local log, data loss from remote log, data loss from
> > > > > metadata
> > > > > > > topic,
> > > > > > > > > > > etc.
> > > > > > > > > > > > > It's worth describing these in detail.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 6. It would be useful to add details about how we
> > plan
> > > on
> > > > > using
> > > > > > > > > > > RocksDB in
> > > > > > > > > > > > > the default implementation of
> > > `RemoteLogMetadataManager`.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 7. For a READ_COMMITTED FetchRequest, how do we
> > > retrieve
> > > > > and
> > > > > > > return
> > > > > > > > > > the
> > > > > > > > > > > > > aborted transaction metadata?
> > > > > > > > > > > > >
> > > > > > > > > > > > > 8. The `LogSegmentData` class assumes that we have a
> > > log
> > > > > > > segment,
> > > > > > > > > > > offset
> > > > > > > > > > > > > index, time index, transaction index, producer
> > > snapshot and
> > > > > > > leader
> > > > > > > > > > > epoch
> > > > > > > > > > > > > index. How do we deal with cases where we do not have
> > > one
> > > > > or
> > > > > > > more of
> > > > > > > > > > > these?
> > > > > > > > > > > > > For example, we may not have a transaction index or
> > > > > producer
> > > > > > > snapshot
> > > > > > > > > > > for a
> > > > > > > > > > > > > particular segment. The former is optional, and the
> > > latter
> > > > > is
> > > > > > > only
> > > > > > > > > > > kept for
> > > > > > > > > > > > > up to the 3 latest segments.
> > > > > > > > > > > > >
> > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > Dhruvil
> > > > > > > > > > > > >
> > > > > > > > > > > > > On Mon, Sep 7, 2020 at 6:54 PM Harsha Ch <
> > > > > harsha.ch@gmail.com>
> > > > > > > > > > wrote:
> > > > > > > > > > > > >
> > > > > > > > > > > > > > Hi All,
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > We are all working through the last meeting
> > feedback.
> > > > > I'll
> > > > > > > cancel
> > > > > > > > > > the
> > > > > > > > > > > > > > tomorrow 's meeting and we can meanwhile continue
> > our
> > > > > > > discussion in
> > > > > > > > > > > mailing
> > > > > > > > > > > > > > list. We can start the regular meeting from next
> > week
> > > > > > > onwards.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Harsha
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > On Fri, Sep 04, 2020 at 8:41 AM, Satish Duggana <
> > > > > > > > > > > satish.duggana@gmail.com
> > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Hi Jun,
> > > > > > > > > > > > > > > Thanks for your thorough review and comments.
> > > Please
> > > > > find
> > > > > > > the
> > > > > > > > > > > inline
> > > > > > > > > > > > > > > replies below.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 600. The topic deletion logic needs more details.
> > > > > > > > > > > > > > > 600.1 The KIP mentions "The controller considers
> > > the
> > > > > topic
> > > > > > > > > > > partition is
> > > > > > > > > > > > > > > deleted only when it determines that there are no
> > > log
> > > > > > > segments
> > > > > > > > > > for
> > > > > > > > > > > that
> > > > > > > > > > > > > > > topic partition by using RLMM". How is this done?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > It uses RLMM#listSegments() returns all the
> > > segments
> > > > > for
> > > > > > > the
> > > > > > > > > > given
> > > > > > > > > > > topic
> > > > > > > > > > > > > > > partition.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 600.2 "If the delete option is enabled then the
> > > leader
> > > > > > > will stop
> > > > > > > > > > > RLM task
> > > > > > > > > > > > > > > and stop processing and it sets all the remote
> > log
> > > > > segment
> > > > > > > > > > > metadata of
> > > > > > > > > > > > > > > that partition with a delete marker and publishes
> > > them
> > > > > to
> > > > > > > RLMM."
> > > > > > > > > > We
> > > > > > > > > > > > > > > discussed this earlier. When a topic is being
> > > deleted,
> > > > > > > there may
> > > > > > > > > > > not be a
> > > > > > > > > > > > > > > leader for the deleted partition.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > This is a good point. As suggested in the
> > meeting,
> > > we
> > > > > will
> > > > > > > add a
> > > > > > > > > > > separate
> > > > > > > > > > > > > > > section for topic/partition deletion lifecycle
> > and
> > > this
> > > > > > > scenario
> > > > > > > > > > > will be
> > > > > > > > > > > > > > > addressed.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 601. Unclean leader election
> > > > > > > > > > > > > > > 601.1 Scenario 1: new empty follower
> > > > > > > > > > > > > > > After step 1, the follower restores up to offset
> > > 3. So
> > > > > why
> > > > > > > does
> > > > > > > > > > it
> > > > > > > > > > > have
> > > > > > > > > > > > > > > LE-2 <https://issues.apache.org/jira/browse/LE-2
> > >
> > > at
> > > > > > > offset 5?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Nice catch. It was showing the leader epoch
> > fetched
> > > > > from
> > > > > > > the
> > > > > > > > > > remote
> > > > > > > > > > > > > > > storage. It should be shown with the truncated
> > till
> > > > > offset
> > > > > > > 3.
> > > > > > > > > > > Updated the
> > > > > > > > > > > > > > > KIP.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 601.2 senario 5: After Step 3, leader A has
> > > > > inconsistent
> > > > > > > data
> > > > > > > > > > > between its
> > > > > > > > > > > > > > > local and the tiered data. For example. offset 3
> > > has
> > > > > msg 3
> > > > > > > LE-0
> > > > > > > > > > > <https://issues.apache.org/jira/browse/LE-0> locally,
> > > > > > > > > > > > > > > but msg 5 LE-1 <
> > > > > https://issues.apache.org/jira/browse/LE-1>
> > > > > > > in
> > > > > > > > > > > the remote store. While it's ok for the unclean leader
> > > > > > > > > > > > > > > to lose data, it should still return consistent
> > > data,
> > > > > > > whether
> > > > > > > > > > it's
> > > > > > > > > > > from
> > > > > > > > > > > > > > > the local or the remote store.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > There is no inconsistency here as LE-0
> > > > > > > > > > > <https://issues.apache.org/jira/browse/LE-0> offsets are
> > > [0,
> > > > > 4]
> > > > > > > and LE-2
> > > > > > > > > > > <https://issues.apache.org/jira/browse/LE-2>:
> > > > > > > > > > > > > > > [5, ]. It will always get the right records for
> > the
> > > > > given
> > > > > > > offset
> > > > > > > > > > > and
> > > > > > > > > > > > > > > leader epoch. In case of remote, RSM is invoked
> > to
> > > get
> > > > > the
> > > > > > > remote
> > > > > > > > > > > log
> > > > > > > > > > > > > > > segment that contains the given offset with the
> > > leader
> > > > > > > epoch.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 601.4 It seems that retention is based on
> > > > > > > > > > > > > > > listRemoteLogSegments(TopicPartition
> > > topicPartition,
> > > > > long
> > > > > > > > > > > leaderEpoch).
> > > > > > > > > > > > > > > When there is an unclean leader election, it's
> > > possible
> > > > > > > for the
> > > > > > > > > > new
> > > > > > > > > > > > > > leader
> > > > > > > > > > > > > > > to not to include certain epochs in its epoch
> > > cache.
> > > > > How
> > > > > > > are
> > > > > > > > > > remote
> > > > > > > > > > > > > > > segments associated with those epochs being
> > > cleaned?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > That is a good point. This leader will also
> > > cleanup the
> > > > > > > epochs
> > > > > > > > > > > earlier to
> > > > > > > > > > > > > > > its start leader epoch and delete those segments.
> > > It
> > > > > gets
> > > > > > > the
> > > > > > > > > > > earliest
> > > > > > > > > > > > > > > epoch for a partition and starts deleting
> > segments
> > > from
> > > > > > > that
> > > > > > > > > > leader
> > > > > > > > > > > > > > epoch.
> > > > > > > > > > > > > > > We need one more API in RLMM to get the earliest
> > > leader
> > > > > > > epoch.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 601.5 The KIP discusses the handling of unclean
> > > leader
> > > > > > > elections
> > > > > > > > > > > for user
> > > > > > > > > > > > > > > topics. What about unclean leader elections on
> > > > > > > > > > > > > > > __remote_log_segment_metadata?
> > > > > > > > > > > > > > > This is the same as other system topics like
> > > > > > > consumer_offsets,
> > > > > > > > > > > > > > > __transaction_state topics. As discussed in the
> > > > > meeting,
> > > > > > > we will
> > > > > > > > > > > add the
> > > > > > > > > > > > > > > behavior of __remote_log_segment_metadata topic’s
> > > > > unclean
> > > > > > > leader
> > > > > > > > > > > > > > > truncation.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 602. It would be useful to clarify the
> > limitations
> > > in
> > > > > the
> > > > > > > initial
> > > > > > > > > > > > > > release.
> > > > > > > > > > > > > > > The KIP mentions not supporting compacted topics.
> > > What
> > > > > > > about JBOD
> > > > > > > > > > > and
> > > > > > > > > > > > > > > changing the configuration of a topic from delete
> > > to
> > > > > > > compact
> > > > > > > > > > after
> > > > > > > > > > > > > > remote.
> > > > > > > > > > > > > > > log. storage. enable (
> > > > > http://remote.log.storage.enable/
> > > > > > > ) is
> > > > > > > > > > > enabled?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > This was updated in the KIP earlier.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 603. RLM leader tasks:
> > > > > > > > > > > > > > > 603.1"It checks for rolled over LogSegments
> > (which
> > > have
> > > > > > > the last
> > > > > > > > > > > message
> > > > > > > > > > > > > > > offset less than last stable offset of that topic
> > > > > > > partition) and
> > > > > > > > > > > copies
> > > > > > > > > > > > > > > them along with their offset/time/transaction
> > > indexes
> > > > > and
> > > > > > > leader
> > > > > > > > > > > epoch
> > > > > > > > > > > > > > > cache to the remote tier." It needs to copy the
> > > > > producer
> > > > > > > snapshot
> > > > > > > > > > > too.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Right. It copies producer snapshots too as
> > > mentioned in
> > > > > > > > > > > LogSegmentData.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 603.2 "Local logs are not cleaned up till those
> > > > > segments
> > > > > > > are
> > > > > > > > > > copied
> > > > > > > > > > > > > > > successfully to remote even though their
> > retention
> > > > > > > time/size is
> > > > > > > > > > > reached"
> > > > > > > > > > > > > > > This seems weird. If the tiering stops because
> > the
> > > > > remote
> > > > > > > store
> > > > > > > > > > is
> > > > > > > > > > > not
> > > > > > > > > > > > > > > available, we don't want the local data to grow
> > > > > forever.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > It was clarified in the discussion that the
> > > comment was
> > > > > > > more
> > > > > > > > > > about
> > > > > > > > > > > the
> > > > > > > > > > > > > > > local storage goes beyond the log.retention. The
> > > above
> > > > > > > statement
> > > > > > > > > > > is about
> > > > > > > > > > > > > > > local.log.retention but not for the complete
> > > > > > > log.retention. When
> > > > > > > > > > it
> > > > > > > > > > > > > > > reaches the log.retention then it will delete the
> > > local
> > > > > > > logs even
> > > > > > > > > > > though
> > > > > > > > > > > > > > > those are not copied to remote storage.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 604. "RLM maintains a bounded cache(possibly LRU)
> > > of
> > > > > the
> > > > > > > index
> > > > > > > > > > > files of
> > > > > > > > > > > > > > > remote log segments to avoid multiple index
> > fetches
> > > > > from
> > > > > > > the
> > > > > > > > > > remote
> > > > > > > > > > > > > > > storage. These indexes can be used in the same
> > way
> > > as
> > > > > local
> > > > > > > > > > segment
> > > > > > > > > > > > > > > indexes are used." Could you provide more details
> > > on
> > > > > this?
> > > > > > > Are
> > > > > > > > > > the
> > > > > > > > > > > > > > indexes
> > > > > > > > > > > > > > > cached in memory or on disk? If on disk, where
> > are
> > > they
> > > > > > > stored?
> > > > > > > > > > > Are the
> > > > > > > > > > > > > > > cached indexes bound by a certain size?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > These are cached on disk and stored in log.dir
> > > with a
> > > > > name
> > > > > > > > > > > > > > > “__remote_log_index_cache”. They are bound by the
> > > total
> > > > > > > size.
> > > > > > > > > > This
> > > > > > > > > > > will
> > > > > > > > > > > > > > be
> > > > > > > > > > > > > > > exposed as a user configuration,
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 605. BuildingRemoteLogAux
> > > > > > > > > > > > > > > 605.1 In this section, two options are listed.
> > > Which
> > > > > one is
> > > > > > > > > > chosen?
> > > > > > > > > > > > > > > Option-2, updated the KIP.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 605.2 In option 2, it says "Build the local
> > leader
> > > > > epoch
> > > > > > > cache by
> > > > > > > > > > > cutting
> > > > > > > > > > > > > > > the leader epoch sequence received from remote
> > > storage
> > > > > to
> > > > > > > [LSO,
> > > > > > > > > > > ELO].
> > > > > > > > > > > > > > (LSO
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > = log start offset)." We need to do the same
> > thing
> > > for
> > > > > the
> > > > > > > > > > producer
> > > > > > > > > > > > > > > snapshot. However, it's hard to cut the producer
> > > > > snapshot
> > > > > > > to an
> > > > > > > > > > > earlier
> > > > > > > > > > > > > > > offset. Another option is to simply take the
> > > lastOffset
> > > > > > > from the
> > > > > > > > > > > remote
> > > > > > > > > > > > > > > segment and use that as the starting fetch offset
> > > in
> > > > > the
> > > > > > > > > > follower.
> > > > > > > > > > > This
> > > > > > > > > > > > > > > avoids the need for cutting.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Right, this was mentioned in the “transactional
> > > > > support”
> > > > > > > section
> > > > > > > > > > > about
> > > > > > > > > > > > > > > adding these details.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 606. ListOffsets: Since we need a version bump,
> > > could
> > > > > you
> > > > > > > > > > document
> > > > > > > > > > > it
> > > > > > > > > > > > > > > under a protocol change section?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Sure, we will update the KIP.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 607. "LogStartOffset of a topic can point to
> > > either of
> > > > > > > local
> > > > > > > > > > > segment or
> > > > > > > > > > > > > > > remote segment but it is initialised and
> > > maintained in
> > > > > the
> > > > > > > Log
> > > > > > > > > > > class like
> > > > > > > > > > > > > > > now. This is already maintained in `Log` class
> > > while
> > > > > > > loading the
> > > > > > > > > > > logs and
> > > > > > > > > > > > > > > it can also be fetched from
> > > RemoteLogMetadataManager."
> > > > > > > What will
> > > > > > > > > > > happen
> > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > the existing logic (e.g. log recovery) that
> > > currently
> > > > > > > depends on
> > > > > > > > > > > > > > > logStartOffset but assumes it's local?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > They use a field called localLogStartOffset which
> > > is
> > > > > the
> > > > > > > local
> > > > > > > > > > log
> > > > > > > > > > > start
> > > > > > > > > > > > > > > offset..
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 608. Handle expired remote segment: How does it
> > > pick
> > > > > up new
> > > > > > > > > > > > > > logStartOffset
> > > > > > > > > > > > > > > from deleteRecords?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Good point. This was not addressed in the KIP.
> > Will
> > > > > update
> > > > > > > the
> > > > > > > > > > KIP
> > > > > > > > > > > on how
> > > > > > > > > > > > > > > the RLM task handles this scenario.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 609. RLMM message format:
> > > > > > > > > > > > > > > 609.1 It includes both MaxTimestamp and
> > > EventTimestamp.
> > > > > > > Where
> > > > > > > > > > does
> > > > > > > > > > > it get
> > > > > > > > > > > > > > > both since the message in the log only contains
> > one
> > > > > > > timestamp?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > `EventTimeStamp` is the timestamp at which that
> > > segment
> > > > > > > metadata
> > > > > > > > > > > event is
> > > > > > > > > > > > > > > generated. This is more for audits.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 609.2 If we change just the state (e.g. to
> > > > > > > DELETE_STARTED), it
> > > > > > > > > > > seems it's
> > > > > > > > > > > > > > > wasteful to have to include all other fields not
> > > > > changed.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > This is a good point. We thought about
> > incremental
> > > > > > > updates. But
> > > > > > > > > > we
> > > > > > > > > > > want
> > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > make sure all the events are in the expected
> > order
> > > and
> > > > > take
> > > > > > > > > > action
> > > > > > > > > > > based
> > > > > > > > > > > > > > > on the latest event. Will think through the
> > > approaches
> > > > > in
> > > > > > > detail
> > > > > > > > > > > and
> > > > > > > > > > > > > > > update here.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 609.3 Could you document which process makes the
> > > > > following
> > > > > > > > > > > transitions
> > > > > > > > > > > > > > > DELETE_MARKED, DELETE_STARTED, DELETE_FINISHED?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Okay, will document more details.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 610. remote.log.reader.max.pending.tasks:
> > "Maximum
> > > > > remote
> > > > > > > log
> > > > > > > > > > > reader
> > > > > > > > > > > > > > > thread pool task queue size. If the task queue is
> > > full,
> > > > > > > broker
> > > > > > > > > > > will stop
> > > > > > > > > > > > > > > reading remote log segments." What does the
> > broker
> > > do
> > > > > if
> > > > > > > the
> > > > > > > > > > queue
> > > > > > > > > > > is
> > > > > > > > > > > > > > > full?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > It returns an error for this topic partition.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 611. What do we return if the request
> > offset/epoch
> > > > > doesn't
> > > > > > > exist
> > > > > > > > > > > in the
> > > > > > > > > > > > > > > following API?
> > > > > > > > > > > > > > > RemoteLogSegmentMetadata
> > > > > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > > > > > > > topicPartition, long offset, int epochForOffset)
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > This returns null. But we prefer to update the
> > > return
> > > > > type
> > > > > > > as
> > > > > > > > > > > Optional
> > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > return Empty if that does not exist.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > Satish.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > On Tue, Sep 1, 2020 at 9:45 AM Jun Rao < jun@
> > > > > confluent.
> > > > > > > io (
> > > > > > > > > > > > > > > jun@confluent.io ) > wrote:
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >> Hi, Satish,
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >> Thanks for the updated KIP. Made another pass. A
> > > few
> > > > > more
> > > > > > > > > > comments
> > > > > > > > > > > > > > below.
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >> 600. The topic deletion logic needs more
> > details.
> > > > > > > > > > > > > > >> 600.1 The KIP mentions "The controller considers
> > > the
> > > > > topic
> > > > > > > > > > > partition is
> > > > > > > > > > > > > > >> deleted only when it determines that there are
> > no
> > > log
> > > > > > > segments
> > > > > > > > > > > for that
> > > > > > > > > > > > > > >> topic partition by using RLMM". How is this
> > done?
> > > > > 600.2
> > > > > > > "If the
> > > > > > > > > > > delete
> > > > > > > > > > > > > > >> option is enabled then the leader will stop RLM
> > > task
> > > > > and
> > > > > > > stop
> > > > > > > > > > > processing
> > > > > > > > > > > > > > >> and it sets all the remote log segment metadata
> > of
> > > > > that
> > > > > > > > > > partition
> > > > > > > > > > > with a
> > > > > > > > > > > > > > >> delete marker and publishes them to RLMM." We
> > > > > discussed
> > > > > > > this
> > > > > > > > > > > earlier.
> > > > > > > > > > > > > > When
> > > > > > > > > > > > > > >> a topic is being deleted, there may not be a
> > > leader
> > > > > for
> > > > > > > the
> > > > > > > > > > > deleted
> > > > > > > > > > > > > > >> partition.
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >> 601. Unclean leader election
> > > > > > > > > > > > > > >> 601.1 Scenario 1: new empty follower
> > > > > > > > > > > > > > >> After step 1, the follower restores up to offset
> > > 3. So
> > > > > > > why does
> > > > > > > > > > > it have
> > > > > > > > > > > > > > >> LE-2 <
> > https://issues.apache.org/jira/browse/LE-2>
> > > at
> > > > > > > offset 5?
> > > > > > > > > > > > > > >> 601.2 senario 5: After Step 3, leader A has
> > > > > inconsistent
> > > > > > > data
> > > > > > > > > > > between
> > > > > > > > > > > > > > its
> > > > > > > > > > > > > > >> local and the tiered data. For example. offset 3
> > > has
> > > > > msg
> > > > > > > 3 LE-0
> > > > > > > > > > > <https://issues.apache.org/jira/browse/LE-0> locally,
> > > > > > > > > > > > > > >> but msg 5 LE-1 <
> > > > > > > https://issues.apache.org/jira/browse/LE-1> in
> > > > > > > > > > > the remote store. While it's ok for the unclean leader
> > > > > > > > > > > > > > >> to lose data, it should still return consistent
> > > data,
> > > > > > > whether
> > > > > > > > > > > it's from
> > > > > > > > > > > > > > >> the local or the remote store.
> > > > > > > > > > > > > > >> 601.3 The follower picks up log start offset
> > > using the
> > > > > > > following
> > > > > > > > > > > api.
> > > > > > > > > > > > > > >> Suppose that we have 3 remote segments (LE,
> > > > > > > SegmentStartOffset)
> > > > > > > > > > > as (2,
> > > > > > > > > > > > > > >> 10),
> > > > > > > > > > > > > > >> (3, 20) and (7, 15) due to an unclean leader
> > > election.
> > > > > > > Using the
> > > > > > > > > > > > > > following
> > > > > > > > > > > > > > >> api will cause logStartOffset to go backward
> > from
> > > 20
> > > > > to
> > > > > > > 15. How
> > > > > > > > > > > do we
> > > > > > > > > > > > > > >> prevent that?
> > > > > > > > > > > > > > >> earliestLogOffset(TopicPartition topicPartition,
> > > int
> > > > > > > > > > leaderEpoch)
> > > > > > > > > > > 601.4
> > > > > > > > > > > > > > It
> > > > > > > > > > > > > > >> seems that retention is based on
> > > > > > > > > > > > > > >> listRemoteLogSegments(TopicPartition
> > > topicPartition,
> > > > > long
> > > > > > > > > > > leaderEpoch).
> > > > > > > > > > > > > > >> When there is an unclean leader election, it's
> > > > > possible
> > > > > > > for the
> > > > > > > > > > > new
> > > > > > > > > > > > > > leader
> > > > > > > > > > > > > > >> to not to include certain epochs in its epoch
> > > cache.
> > > > > How
> > > > > > > are
> > > > > > > > > > > remote
> > > > > > > > > > > > > > >> segments associated with those epochs being
> > > cleaned?
> > > > > > > 601.5 The
> > > > > > > > > > KIP
> > > > > > > > > > > > > > >> discusses the handling of unclean leader
> > > elections for
> > > > > > > user
> > > > > > > > > > > topics. What
> > > > > > > > > > > > > > >> about unclean leader elections on
> > > > > > > > > > > > > > >> __remote_log_segment_metadata?
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >> 602. It would be useful to clarify the
> > > limitations in
> > > > > the
> > > > > > > > > > initial
> > > > > > > > > > > > > > release.
> > > > > > > > > > > > > > >> The KIP mentions not supporting compacted
> > topics.
> > > What
> > > > > > > about
> > > > > > > > > > JBOD
> > > > > > > > > > > and
> > > > > > > > > > > > > > >> changing the configuration of a topic from
> > delete
> > > to
> > > > > > > compact
> > > > > > > > > > after
> > > > > > > > > > > > > > remote.
> > > > > > > > > > > > > > >> log. storage. enable (
> > > > > http://remote.log.storage.enable/
> > > > > > > ) is
> > > > > > > > > > > enabled?
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >> 603. RLM leader tasks:
> > > > > > > > > > > > > > >> 603.1"It checks for rolled over LogSegments
> > (which
> > > > > have
> > > > > > > the last
> > > > > > > > > > > message
> > > > > > > > > > > > > > >> offset less than last stable offset of that
> > topic
> > > > > > > partition) and
> > > > > > > > > > > copies
> > > > > > > > > > > > > > >> them along with their offset/time/transaction
> > > indexes
> > > > > and
> > > > > > > leader
> > > > > > > > > > > epoch
> > > > > > > > > > > > > > >> cache to the remote tier." It needs to copy the
> > > > > producer
> > > > > > > > > > snapshot
> > > > > > > > > > > too.
> > > > > > > > > > > > > > >> 603.2 "Local logs are not cleaned up till those
> > > > > segments
> > > > > > > are
> > > > > > > > > > > copied
> > > > > > > > > > > > > > >> successfully to remote even though their
> > retention
> > > > > > > time/size is
> > > > > > > > > > > reached"
> > > > > > > > > > > > > > >> This seems weird. If the tiering stops because
> > the
> > > > > remote
> > > > > > > store
> > > > > > > > > > > is not
> > > > > > > > > > > > > > >> available, we don't want the local data to grow
> > > > > forever.
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >> 604. "RLM maintains a bounded cache(possibly
> > LRU)
> > > of
> > > > > the
> > > > > > > index
> > > > > > > > > > > files of
> > > > > > > > > > > > > > >> remote log segments to avoid multiple index
> > > fetches
> > > > > from
> > > > > > > the
> > > > > > > > > > > remote
> > > > > > > > > > > > > > >> storage. These indexes can be used in the same
> > > way as
> > > > > > > local
> > > > > > > > > > > segment
> > > > > > > > > > > > > > >> indexes are used." Could you provide more
> > details
> > > on
> > > > > > > this? Are
> > > > > > > > > > the
> > > > > > > > > > > > > > indexes
> > > > > > > > > > > > > > >> cached in memory or on disk? If on disk, where
> > are
> > > > > they
> > > > > > > stored?
> > > > > > > > > > > Are the
> > > > > > > > > > > > > > >> cached indexes bound by a certain size?
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >> 605. BuildingRemoteLogAux
> > > > > > > > > > > > > > >> 605.1 In this section, two options are listed.
> > > Which
> > > > > one
> > > > > > > is
> > > > > > > > > > > chosen?
> > > > > > > > > > > > > > 605.2
> > > > > > > > > > > > > > >> In option 2, it says "Build the local leader
> > epoch
> > > > > cache
> > > > > > > by
> > > > > > > > > > > cutting the
> > > > > > > > > > > > > > >> leader epoch sequence received from remote
> > > storage to
> > > > > > > [LSO,
> > > > > > > > > > ELO].
> > > > > > > > > > > (LSO
> > > > > > > > > > > > > > >> = log start offset)." We need to do the same
> > thing
> > > > > for the
> > > > > > > > > > > producer
> > > > > > > > > > > > > > >> snapshot. However, it's hard to cut the producer
> > > > > snapshot
> > > > > > > to an
> > > > > > > > > > > earlier
> > > > > > > > > > > > > > >> offset. Another option is to simply take the
> > > > > lastOffset
> > > > > > > from the
> > > > > > > > > > > remote
> > > > > > > > > > > > > > >> segment and use that as the starting fetch
> > offset
> > > in
> > > > > the
> > > > > > > > > > > follower. This
> > > > > > > > > > > > > > >> avoids the need for cutting.
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >> 606. ListOffsets: Since we need a version bump,
> > > could
> > > > > you
> > > > > > > > > > > document it
> > > > > > > > > > > > > > >> under a protocol change section?
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >> 607. "LogStartOffset of a topic can point to
> > > either of
> > > > > > > local
> > > > > > > > > > > segment or
> > > > > > > > > > > > > > >> remote segment but it is initialised and
> > > maintained in
> > > > > > > the Log
> > > > > > > > > > > class
> > > > > > > > > > > > > > like
> > > > > > > > > > > > > > >> now. This is already maintained in `Log` class
> > > while
> > > > > > > loading the
> > > > > > > > > > > logs
> > > > > > > > > > > > > > and
> > > > > > > > > > > > > > >> it can also be fetched from
> > > RemoteLogMetadataManager."
> > > > > > > What will
> > > > > > > > > > > happen
> > > > > > > > > > > > > > to
> > > > > > > > > > > > > > >> the existing logic (e.g. log recovery) that
> > > currently
> > > > > > > depends on
> > > > > > > > > > > > > > >> logStartOffset but assumes it's local?
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >> 608. Handle expired remote segment: How does it
> > > pick
> > > > > up
> > > > > > > new
> > > > > > > > > > > > > > logStartOffset
> > > > > > > > > > > > > > >> from deleteRecords?
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >> 609. RLMM message format:
> > > > > > > > > > > > > > >> 609.1 It includes both MaxTimestamp and
> > > > > EventTimestamp.
> > > > > > > Where
> > > > > > > > > > > does it
> > > > > > > > > > > > > > get
> > > > > > > > > > > > > > >> both since the message in the log only contains
> > > one
> > > > > > > timestamp?
> > > > > > > > > > > 609.2 If
> > > > > > > > > > > > > > we
> > > > > > > > > > > > > > >> change just the state (e.g. to DELETE_STARTED),
> > it
> > > > > seems
> > > > > > > it's
> > > > > > > > > > > wasteful
> > > > > > > > > > > > > > to
> > > > > > > > > > > > > > >> have to include all other fields not changed.
> > > 609.3
> > > > > Could
> > > > > > > you
> > > > > > > > > > > document
> > > > > > > > > > > > > > >> which process makes the following transitions
> > > > > > > DELETE_MARKED,
> > > > > > > > > > > > > > >> DELETE_STARTED, DELETE_FINISHED?
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >> 610. remote.log.reader.max.pending.tasks:
> > "Maximum
> > > > > remote
> > > > > > > log
> > > > > > > > > > > reader
> > > > > > > > > > > > > > >> thread pool task queue size. If the task queue
> > is
> > > > > full,
> > > > > > > broker
> > > > > > > > > > > will stop
> > > > > > > > > > > > > > >> reading remote log segments." What does the
> > > broker do
> > > > > if
> > > > > > > the
> > > > > > > > > > > queue is
> > > > > > > > > > > > > > >> full?
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >> 611. What do we return if the request
> > offset/epoch
> > > > > > > doesn't exist
> > > > > > > > > > > in the
> > > > > > > > > > > > > > >> following API?
> > > > > > > > > > > > > > >> RemoteLogSegmentMetadata
> > > > > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > > > > > > >> topicPartition, long offset, int epochForOffset)
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >> Jun
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >> On Mon, Aug 31, 2020 at 11:19 AM Satish Duggana
> > <
> > > > > satish.
> > > > > > > > > > duggana@
> > > > > > > > > > > > > > gmail. com
> > > > > > > > > > > > > > >> ( satish.duggana@gmail.com ) > wrote:
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>> KIP is updated with
> > > > > > > > > > > > > > >>> - Remote log segment metadata topic message
> > > > > > > format/schema.
> > > > > > > > > > > > > > >>> - Added remote log segment metadata state
> > > > > transitions and
> > > > > > > > > > > explained how
> > > > > > > > > > > > > > >>> the deletion of segments is handled, including
> > > the
> > > > > case
> > > > > > > of
> > > > > > > > > > > partition
> > > > > > > > > > > > > > >>> deletions.
> > > > > > > > > > > > > > >>> - Added a few more limitations in the "Non
> > goals"
> > > > > > > section.
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>> Thanks,
> > > > > > > > > > > > > > >>> Satish.
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>> On Thu, Aug 27, 2020 at 12:42 AM Harsha Ch <
> > > harsha.
> > > > > ch@
> > > > > > > > > > gmail.
> > > > > > > > > > > com (
> > > > > > > > > > > > > > >>> harsha.ch@gmail.com ) > wrote:
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>> Updated the KIP with Meeting Notes section
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>> https:/ / cwiki. apache. org/ confluence/
> > > display/
> > > > > KAFKA/
> > > > > > > > > > > > > > KIP-405 <
> > > https://issues.apache.org/jira/browse/KIP-405>
> > > > > > > > > > >
> > > %3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> > > > > > > > > > > > > > >>> (
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > >
> > >
> > https://cwiki.apache.org/confluence/display/KAFKA/KIP-405%3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> > > > > > > > > > > > > > >>> )
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>> On Tue, Aug 25, 2020 at 1:03 PM Jun Rao < jun@
> > > > > > > confluent. io
> > > > > > > > > > (
> > > > > > > > > > > > > > >>>> jun@confluent.io ) > wrote:
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>> Hi, Harsha,
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>> Thanks for the summary. Could you add the
> > > summary
> > > > > and
> > > > > > > the
> > > > > > > > > > > recording
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>> link to
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>> the last section of
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>> https:/ / cwiki. apache. org/ confluence/
> > > display/
> > > > > KAFKA/
> > > > > > > > > > > > > > Kafka+Improvement+Proposals
> > > > > > > > > > > > > > >>> (
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > >
> > >
> > https://cwiki.apache.org/confluence/display/KAFKA/Kafka+Improvement+Proposals
> > > > > > > > > > > > > > >>> )
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>> ?
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>> Jun
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>> On Tue, Aug 25, 2020 at 11:12 AM Harsha
> > > > > Chintalapani <
> > > > > > > kafka@
> > > > > > > > > > > > > > harsha. io (
> > > > > > > > > > > > > > >>>>> kafka@harsha.io ) > wrote:
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>> Thanks everyone for attending the meeting
> > > today.
> > > > > > > > > > > > > > >>>>>> Here is the recording
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>> https:/ / drive. google. com/ file/ d/
> > > > > > > > > > > > > > 14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/ view?usp=sharing
> > > > > > > > > > > > > > >>> (
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > >
> > > > >
> > >
> > https://drive.google.com/file/d/14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/view?usp=sharing
> > > > > > > > > > > > > > >>> )
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>> Notes:
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>> 1. KIP is updated with follower fetch
> > > protocol and
> > > > > > > ready to
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>> reviewed
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>> 2. Satish to capture schema of internal
> > > metadata
> > > > > > > topic in
> > > > > > > > > > the
> > > > > > > > > > > KIP
> > > > > > > > > > > > > > >>>>>> 3. We will update the KIP with details of
> > > > > different
> > > > > > > cases
> > > > > > > > > > > > > > >>>>>> 4. Test plan will be captured in a doc and
> > > will
> > > > > add
> > > > > > > to the
> > > > > > > > > > KIP
> > > > > > > > > > > > > > >>>>>> 5. Add a section "Limitations" to capture
> > the
> > > > > > > capabilities
> > > > > > > > > > > that
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>> will
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>> be
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>> introduced with this KIP and what will not
> > be
> > > > > covered
> > > > > > > in
> > > > > > > > > > this
> > > > > > > > > > > KIP.
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>> Please add to it I missed anything. Will
> > > produce a
> > > > > > > formal
> > > > > > > > > > > meeting
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>> notes
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>> from next meeting onwards.
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>> Thanks,
> > > > > > > > > > > > > > >>>>>> Harsha
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>> On Mon, Aug 24, 2020 at 9:42 PM, Ying Zheng
> > <
> > > > > yingz@
> > > > > > > uber.
> > > > > > > > > > > com.
> > > > > > > > > > > > > > invalid (
> > > > > > > > > > > > > > >>>>>> yingz@uber.com.invalid ) > wrote:
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> We did some basic feature tests at Uber.
> > The
> > > test
> > > > > > > cases and
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>> results are
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> shared in this google doc:
> > > > > > > > > > > > > > >>>>>>> https:/ / docs. google. com/ spreadsheets/
> > > d/ (
> > > > > > > > > > > > > > >>>>>>> https://docs.google.com/spreadsheets/d/ )
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > >
> > 1XhNJqjzwXvMCcAOhEH0sSXU6RTvyoSf93DHF-YMfGLk/edit?usp=sharing
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> The performance test results were already
> > > shared
> > > > > in
> > > > > > > the KIP
> > > > > > > > > > > last
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>> month.
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> On Mon, Aug 24, 2020 at 11:10 AM Harsha Ch
> > <
> > > > > harsha.
> > > > > > > ch@
> > > > > > > > > > > gmail.
> > > > > > > > > > > > > > com (
> > > > > > > > > > > > > > >>>>>>> harsha.ch@gmail.com ) >
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>> wrote:
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> "Understand commitments towards driving
> > > design &
> > > > > > > > > > > implementation of
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>> the
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>> KIP
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> further and how it aligns with participant
> > > > > interests
> > > > > > > in
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>> contributing to
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>> the
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> efforts (ex: in the context of Uber’s Q3/Q4
> > > > > > > roadmap)." What
> > > > > > > > > > > is that
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>> about?
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> On Mon, Aug 24, 2020 at 11:05 AM Kowshik
> > > > > Prakasam <
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>> kprakasam@ confluent. io (
> > > kprakasam@confluent.io
> > > > > ) >
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> wrote:
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> Hi Harsha,
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> The following google doc contains a
> > proposal
> > > for
> > > > > > > temporary
> > > > > > > > > > > agenda
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>> for
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>> the
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> KIP-405 <
> > > > > > > https://issues.apache.org/jira/browse/KIP-405> <
> > > > > > > > > > > https:/ / issues. apache. org/ jira/ browse/ KIP-405
> > > > > > > > > > > <https://issues.apache.org/jira/browse/KIP-405> (
> > > > > > > > > > > > > > >>>>>>>
> > > https://issues.apache.org/jira/browse/KIP-405 )
> > > > > >
> > > > > > > sync
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>> meeting
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> tomorrow:
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> https:/ / docs. google. com/ document/ d/ (
> > > > > > > > > > > > > > >>>>>>> https://docs.google.com/document/d/ )
> > > > > > > > > > > > > > >>>>>>>
> > > 1pqo8X5LU8TpwfC_iqSuVPezhfCfhGkbGN2TqiPA3LBU/edit
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> .
> > > > > > > > > > > > > > >>>>>>> Please could you add it to the Google
> > > calendar
> > > > > > > invite?
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> Thank you.
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> Cheers,
> > > > > > > > > > > > > > >>>>>>> Kowshik
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> On Thu, Aug 20, 2020 at 10:58 AM Harsha Ch
> > <
> > > > > harsha.
> > > > > > > ch@
> > > > > > > > > > > gmail.
> > > > > > > > > > > > > > com (
> > > > > > > > > > > > > > >>>>>>> harsha.ch@gmail.com ) >
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>> wrote:
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> Hi All,
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> Scheduled a meeting for Tuesday 9am - 10am.
> > > I can
> > > > > > > record
> > > > > > > > > > and
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>> upload for
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> community to be able to follow the
> > > discussion.
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> Jun, please add the required folks on
> > > confluent
> > > > > side.
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> Thanks,
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> Harsha
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> On Thu, Aug 20, 2020 at 12:33 AM, Alexandre
> > > > > Dupriez <
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>> alexandre.dupriez@
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> gmail. com ( http://gmail.com/ ) > wrote:
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> Hi Jun,
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> Many thanks for your initiative.
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> If you like, I am happy to attend at the
> > > time you
> > > > > > > > > > suggested.
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> Many thanks,
> > > > > > > > > > > > > > >>>>>>> Alexandre
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> Le mer. 19 août 2020 à 22:00, Harsha Ch <
> > > > > harsha. ch@
> > > > > > > > > > > gmail. com (
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>> harsha.
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> ch@ gmail. com ( ch@gmail.com ) ) > a
> > écrit
> > > :
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> Hi Jun,
> > > > > > > > > > > > > > >>>>>>> Thanks. This will help a lot. Tuesday will
> > > work
> > > > > for
> > > > > > > us.
> > > > > > > > > > > > > > >>>>>>> -Harsha
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> On Wed, Aug 19, 2020 at 1:24 PM Jun Rao <
> > > jun@
> > > > > > > confluent.
> > > > > > > > > > > io (
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>> jun@
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> confluent. io ( http://confluent.io/ ) ) >
> > > > > wrote:
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> Hi, Satish, Ying, Harsha,
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> Do you think it would be useful to have a
> > > regular
> > > > > > > virtual
> > > > > > > > > > > meeting
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>> to
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>
> > > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> discuss this KIP? The goal of the meeting
> > > will be
> > > > > > > sharing
> > > > > > > > > > > > > > >>>>>>> design/development progress and discussing
> > > any
> > > > > open
> > > > > > > issues
> > > > > > > > > > to
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> accelerate
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> this KIP. If so, will every Tuesday (from
> > > next
> > > > > week)
> > > > > > > > > > 9am-10am
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> PT
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> work for you? I can help set up a Zoom
> > > meeting,
> > > > > > > invite
> > > > > > > > > > > everyone who
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> might
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> be interested, have it recorded and shared,
> > > etc.
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> Thanks,
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> Jun
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> On Tue, Aug 18, 2020 at 11:01 AM Satish
> > > Duggana <
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> satish. duggana@ gmail. com ( satish.
> > > duggana@
> > > > > > > gmail. com
> > > > > > > > > > (
> > > > > > > > > > > > > > >>>>>>> satish.duggana@gmail.com ) ) >
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> wrote:
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> Hi Kowshik,
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> Thanks for looking into the KIP and sending
> > > your
> > > > > > > comments.
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > > >>>>>>> 5001. Under the section "Follower fetch
> > > protocol
> > > > > in
> > > > > > > > > > detail",
> > > > > > > > > > > the
> > > > > > > > > > > > > > >>>>>>> next-local-offset is the offset upto which
> > > the
> > > > > > > segments are
> > > > > > > > > > > copied
> > > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > >
> > > > > > >
> > > > > > >
> > > > >
> > >
> >

Re: [DISCUSS] KIP-405: Kafka Tiered Storage

[Jun Rao <ju...@confluent.io>]

Hi, Satish,

Thanks for the reply. A few more followup comments.

6022. For packages used for server plugins, the convention is to
use org.apache.kafka.server. See java-based Authorizer as an example.

9100. Do we need DeletePartitionStateRecord in flat_file_format? The flat
file captures the state of the remote segments. After a partition is
deleted, it seems that we just need to remove the partitions's remote
segments from the flat file.

9101. Upgrade: It will be useful to allow direct upgrade from an old
version. It seems that's doable. One can just do the normal upgrade first
and wait enough time (for producer snapshots to be built), and then enable
remote storage.

9102. RemotePartitionRemover(RPM) process: Is it true that RPM starts
tracking the remote segments when RLMM.onPartitionLeadershipChanges() is
called with the broker being the leader for __remote_log_metadata
partition? If so, could we document it?

Jun

On Tue, Dec 15, 2020 at 8:47 AM Kowshik Prakasam <kp...@confluent.io>
wrote:

> Hi Satish,
>
> Thanks for the updates! A few more comments below.
>
> 9001. Under the "Upgrade" section, there is a line mentioning: "Upgrade the
> existing Kafka cluster to 2.7 version and allow this to run for the log
> retention of user topics that you want to enable tiered storage. This will
> allow all the topics to have the producer snapshots generated for each log
> segment." -- Which associated change in AK were you referring to here? Is
> it: https://github.com/apache/kafka/pull/7929 ? It seems like I don't see
> it in the 2.7 release branch yet, here is the link:
> https://github.com/apache/kafka/commits/2.7.
>
> 9002. Under the "Upgrade" section, the configuration mentioned is
> 'remote.log.storage.system.enable'. However, under "Public Interfaces"
> section the corresponding configuration is 'remote.storage.system.enable'.
> Could we use the same one in both, maybe
> 'remote.log.storage.system.enable'?
>
> 9003. Under "Per Topic Configuration", the KIP recommends setting
> 'remote.log.storage.enable' to true at a per-topic level. It will be useful
> to add a line that if the user wants to enable it for all topics, then they
> should be able to set the cluster-wide default to true. Also, it will be
> useful to mention that the KIP currently does not support setting it to
> false (after it is set to true), and add that to the future work section.
>
> 9004. Under "Committed offsets file format", the sample provided shows
> partition number and offset. Is the topic name required for identifying
> which topic the partitions belong to?
>
> 9005. Under "Internal flat-file store format of remote log metadata", it
> seems useful to specify both topic name and topic ID for debugging
> purposes.
>
> 9006. Under "Internal flat-file store format of remote log metadata", the
> description of "metadata-topic-offset" currently says "offset of the remote
> log metadata topic from which this topic partition's remote log metadata is
> fetched." Just for the wording, perhaps you meant to refer to the offset
> upto which the file has been committed? i.e. "offset of the remote log
> metadata topic upto which this topic partition's remote log metadata has
> been committed into this file."
>
> 9007. Under "Internal flat-file store format of remote log metadata", the
> schema of the payload (i.e. beyond the header) seems to contain the events
> from the metadata topic. It seems useful to instead persist the
> representation of the materialized state of the events, so that for the
> same segment only the latest state is stored. Besides reducing storage
> footprint, this also is likely to relate directly with the in-memory
> representation of the RLMM cache (which probably is some kind of a Map with
> key being segment ID and value being the segment state), so recovery from
> disk will be straightforward.
>
> 9008. Under "Topic deletion lifecycle", step (1), it will be useful to
> mention when in the deletion flow does the controller publish the
> delete_partition_marked event to say that the partition is marked for
> deletion?
>
> 9009. There are ~4 TODOs in the KIP. Could you please address these or
> remove them?
>
> 9010. There is a reference to a Google doc on the KIP which was used
> earlier for discussions. Please could you remove the reference, since the
> KIP is the source of the truth?
>
> 9011. This feedback is from an earlier comment. In the RemoteStorageManager
> interface, there is an API defined for each file type. For example,
> fetchOffsetIndex, fetchTimestampIndex etc. To avoid the duplication, I'd
> suggest we can instead have a FileType enum and a common get API based on
> the FileType. What do you think?
>
>
> Cheers,
> Kowshik
>
>
> On Mon, Dec 14, 2020 at 11:07 AM Satish Duggana <sa...@gmail.com>
> wrote:
>
> > Hi Jun,
> > Thanks for your comments. Please go through the inline replies.
> >
> >
> > 5102.2: It seems that both positions can just be int. Another option is
> to
> > have two methods. Would it be clearer?
> >
> >     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> > remoteLogSegmentMetadata,  int startPosition)
> throwsRemoteStorageException;
> >
> >     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> > remoteLogSegmentMetadata, int startPosition, int endPosition) throws
> > RemoteStorageException;
> >
> > That makes sense to me, updated the KIP.
> >
> > 6003: Could you also update the javadoc for the return value?
> >
> > Updated.
> >
> > 6020: local.log.retention.bytes: Should it default to log.retention.bytes
> > to be consistent with local.log.retention.ms?
> >
> > Yes, it can be defaulted to log.retention.bytes.
> >
> > 6021: Could you define TopicIdPartition?
> >
> > Added TopicIdPartition in the KIP.
> >
> > 6022: For all public facing classes, could you specify the package name?
> >
> > Updated.
> >
> >
> > Thanks,
> > Satish.
> >
> > On Tue, Dec 8, 2020 at 12:59 AM Jun Rao <ju...@confluent.io> wrote:
> > >
> > > Hi, Satish,
> > >
> > > Thanks for the reply. A few more comments below.
> > >
> > > 5102.2: It seems that both positions can just be int. Another option is
> > to
> > > have two methods. Would it be clearer?
> > >
> > >     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> > > remoteLogSegmentMetadata,
> > >                                     int startPosition) throws
> > > RemoteStorageException;
> > >
> > >     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> > > remoteLogSegmentMetadata,
> > >                                     int startPosition, int endPosition)
> > > throws RemoteStorageException;
> > >
> > > 6003: Could you also update the javadoc for the return value?
> > >
> > > 6010: What kind of tiering throughput have you seen with 5 threads?
> > >
> > > 6020: local.log.retention.bytes: Should it default to
> log.retention.bytes
> > > to be consistent with local.log.retention.ms?
> > >
> > > 6021: Could you define TopicIdPartition?
> > >
> > > 6022: For all public facing classes, could you specify the package
> name?
> > >
> > > It seems that you already added the topicId support. Two other
> remaining
> > > items are (a) the format of local tier metadata storage and (b)
> upgrade.
> > >
> > > Jun
> > >
> > > On Mon, Dec 7, 2020 at 8:56 AM Satish Duggana <
> satish.duggana@gmail.com>
> > > wrote:
> > >
> > > > Hi Jun,
> > > > Thanks for your comments. Please find the inline replies below.
> > > >
> > > > >605.2 It's rare for the follower to need the remote data. So, the
> > current
> > > > approach is fine too. Could you document the process of rebuilding
> the
> > > > producer state since we can't simply trim the producerState to an
> > offset in
> > > > the middle of a segment.
> > > >
> > > > Will clarify in the KIP.
> > > >
> > > > >5102.2 Would it be clearer to make startPosiont long and endPosition
> > of
> > > > Optional<Long>?
> > > >
> > > > We will have arg checks with respective validation. It is not a good
> > > > practice to have arguments with optional as mentioned here.
> > > > https://rules.sonarsource.com/java/RSPEC-3553
> > > >
> > > >
> > > > >5102.5 LogSegmentData still has leaderEpochIndex as File instead of
> > > > ByteBuffer.
> > > >
> > > > Updated.
> > > >
> > > > >5102.7 Could you define all public methods for LogSegmentData?
> > > >
> > > > Updated.
> > > >
> > > > >5103.5 Could you change the reference to rlm_process_interval_ms and
> > > > rlm_retry_interval_ms to the new config names? Also, the retry
> interval
> > > > config seems still missing. It would be useful to support exponential
> > > > backoff with the retry interval config.
> > > >
> > > > Good point. We wanted the retry with truncated exponential backoff,
> > > > updated the KIP.
> > > >
> > > > >5111. "RLM follower fetches the earliest offset for the earliest
> > leader
> > > > epoch by calling RLMM.earliestLogOffset(TopicPartition
> topicPartition,
> > int
> > > > leaderEpoch) and updates that as the log start offset." This text is
> > still
> > > > there. Also, could we remove earliestLogOffset() from RLMM?
> > > >
> > > > Updated.
> > > >
> > > > >5115. There are still references to "remote log cleaners".
> > > >
> > > > Updated.
> > > >
> > > > >6000. Since we are returning new error codes, we need to bump up the
> > > > protocol version for Fetch request. Also, it will be useful to
> > document all
> > > > new error codes and whether they are retriable or not.
> > > >
> > > > Sure, we will add that in the KIP.
> > > >
> > > > >6001. public Map<Long, Long> segmentLeaderEpochs(): Currently,
> > leaderEpoch
> > > > is int32 instead of long.
> > > >
> > > > Updated.
> > > >
> > > > >6002. Is RemoteLogSegmentMetadata.markedForDeletion() needed given
> > > > RemoteLogSegmentMetadata.state()?
> > > >
> > > > No, it is fixed.
> > > >
> > > > >6003. RemoteLogSegmentMetadata
> remoteLogSegmentMetadata(TopicPartition
> > > > topicPartition, long offset, int epochForOffset): Should this return
> > > > Optional<RemoteLogSegmentMetadata>?
> > > >
> > > > That makes sense, updated.
> > > >
> > > > >6005. RemoteLogState: It seems it's better to split it between
> > > > DeletePartitionUpdate and RemoteLogSegmentMetadataUpdate since the
> > states
> > > > are never shared between the two use cases.
> > > >
> > > > Agree with that, updated.
> > > >
> > > > >6006. RLMM.onPartitionLeadershipChanges(): This may be ok. However,
> > is it
> > > > ture that other than the metadata topic, RLMM just needs to know
> > whether
> > > > there is a replica assigned to this broker and doesn't need to know
> > whether
> > > > the replica is the leader or the follower?
> > > >
> > > > That may be true. If the implementation does not need that, it can
> > > > ignore the information in the callback.
> > > >
> > > > >6007: "Handle expired remote segments (leader and follower)": Why is
> > this
> > > > needed in both the leader and the follower?
> > > >
> > > > Updated.
> > > >
> > > > >6008.       "name": "SegmentSizeInBytes",
> > > >                 "type": "int64",
> > > > The segment size can just be int32.
> > > >
> > > > Updated.
> > > >
> > > > >6009. For the record format in the log, it seems that we need to add
> > > > record
> > > > type and record version before the serialized bytes. We can follow
> the
> > > > convention used in
> > > >
> > > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-631%3A+The+Quorum-based+Kafka+Controller#KIP631:TheQuorumbasedKafkaController-RecordFormats
> > > >
> > > > Yes, KIP already mentions that these are serialized before the
> payload
> > > > as below. We will mention explicitly that these two are written
> before
> > > > the data is written.
> > > >
> > > > RLMM instance on broker publishes the message to the topic with key
> as
> > > > null and value with the below format.
> > > >
> > > > type      : unsigned var int, represents the value type. This value
> is
> > > > 'apikey' as mentioned in the schema.
> > > > version : unsigned var int, the 'version' number of the type as
> > > > mentioned in the schema.
> > > > data      : record payload in kafka protocol message format.
> > > >
> > > >
> > > > >6010. remote.log.manager.thread.pool.size: The default value is 10.
> > This
> > > > might be too high when enabling the tiered feature for the first
> time.
> > > > Since there are lots of segments that need to be tiered initially, a
> > large
> > > > number of threads could overwhelm the broker.
> > > >
> > > > Is the default value 5 reasonable?
> > > >
> > > > 6011. "The number of milli seconds to keep the local log segment
> > before it
> > > > gets deleted. If not set, the value in `log.retention.minutes` is
> > used. If
> > > > set to -1, no time limit is applied." We should use log.retention.ms
> > > > instead of log.retention.minutes.
> > > > Nice typo catch. Updated the KIP.
> > > >
> > > > Thanks,
> > > > Satish.
> > > >
> > > > On Thu, Dec 3, 2020 at 8:03 AM Jun Rao <ju...@confluent.io> wrote:
> > > > >
> > > > > Hi, Satish,
> > > > >
> > > > > Thanks for the updated KIP. A few more comments below.
> > > > >
> > > > > 605.2 It's rare for the follower to need the remote data. So, the
> > current
> > > > > approach is fine too. Could you document the process of rebuilding
> > the
> > > > > producer state since we can't simply trim the producerState to an
> > offset
> > > > in
> > > > > the middle of a segment.
> > > > >
> > > > > 5102.2 Would it be clearer to make startPosiont long and
> endPosition
> > of
> > > > > Optional<Long>?
> > > > >
> > > > > 5102.5 LogSegmentData still has leaderEpochIndex as File instead of
> > > > > ByteBuffer.
> > > > >
> > > > > 5102.7 Could you define all public methods for LogSegmentData?
> > > > >
> > > > > 5103.5 Could you change the reference to rlm_process_interval_ms
> and
> > > > > rlm_retry_interval_ms to the new config names? Also, the retry
> > interval
> > > > > config seems still missing. It would be useful to support
> exponential
> > > > > backoff with the retry interval config.
> > > > >
> > > > > 5111. "RLM follower fetches the earliest offset for the earliest
> > leader
> > > > > epoch by calling RLMM.earliestLogOffset(TopicPartition
> > topicPartition,
> > > > int
> > > > > leaderEpoch) and updates that as the log start offset." This text
> is
> > > > still
> > > > > there. Also, could we remove earliestLogOffset() from RLMM?
> > > > >
> > > > > 5115. There are still references to "remote log cleaners".
> > > > >
> > > > > 6000. Since we are returning new error codes, we need to bump up
> the
> > > > > protocol version for Fetch request. Also, it will be useful to
> > document
> > > > all
> > > > > new error codes and whether they are retriable or not.
> > > > >
> > > > > 6001. public Map<Long, Long> segmentLeaderEpochs(): Currently,
> > > > leaderEpoch
> > > > > is int32 instead of long.
> > > > >
> > > > > 6002. Is RemoteLogSegmentMetadata.markedForDeletion() needed given
> > > > > RemoteLogSegmentMetadata.state()?
> > > > >
> > > > > 6003. RemoteLogSegmentMetadata
> > remoteLogSegmentMetadata(TopicPartition
> > > > > topicPartition, long offset, int epochForOffset): Should this
> return
> > > > > Optional<RemoteLogSegmentMetadata>?
> > > > >
> > > > > 6004. DeletePartitionUpdate.epoch(): It would be useful to pick a
> > more
> > > > > indicative name so that people understand what epoch this is.
> > > > >
> > > > > 6005. RemoteLogState: It seems it's better to split it between
> > > > > DeletePartitionUpdate and RemoteLogSegmentMetadataUpdate since the
> > states
> > > > > are never shared between the two use cases.
> > > > >
> > > > > 6006. RLMM.onPartitionLeadershipChanges(): This may be ok. However,
> > is it
> > > > > ture that other than the metadata topic, RLMM just needs to know
> > whether
> > > > > there is a replica assigned to this broker and doesn't need to know
> > > > whether
> > > > > the replica is the leader or the follower?
> > > > >
> > > > > 6007: "Handle expired remote segments (leader and follower)": Why
> is
> > this
> > > > > needed in both the leader and the follower?
> > > > >
> > > > > 6008.       "name": "SegmentSizeInBytes",
> > > > >                 "type": "int64",
> > > > > The segment size can just be int32.
> > > > >
> > > > > 6009. For the record format in the log, it seems that we need to
> add
> > > > record
> > > > > type and record version before the serialized bytes. We can follow
> > the
> > > > > convention used in
> > > > >
> > > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-631%3A+The+Quorum-based+Kafka+Controller#KIP631:TheQuorumbasedKafkaController-RecordFormats
> > > > > .
> > > > >
> > > > > 6010. remote.log.manager.thread.pool.size: The default value is 10.
> > This
> > > > > might be too high when enabling the tiered feature for the first
> > time.
> > > > > Since there are lots of segments that need to be tiered initially,
> a
> > > > large
> > > > > number of threads could overwhelm the broker.
> > > > >
> > > > > 6011. "The number of milli seconds to keep the local log segment
> > before
> > > > it
> > > > > gets deleted. If not set, the value in `log.retention.minutes` is
> > used.
> > > > If
> > > > > set to -1, no time limit is applied." We should use
> log.retention.ms
> > > > > instead of log.retention.minutes.
> > > > >
> > > > > Jun
> > > > >
> > > > > On Tue, Dec 1, 2020 at 2:42 AM Satish Duggana <
> > satish.duggana@gmail.com>
> > > > > wrote:
> > > > >
> > > > > > Hi,
> > > > > > We updated the KIP with the points mentioned in the earlier mail
> > > > > > except for KIP-516 related changes. You can go through them and
> > let us
> > > > > > know if you have any comments. We will update the KIP with the
> > > > > > remaining todo items and KIP-516 related changes by end of this
> > > > > > week(5th Dec).
> > > > > >
> > > > > > Thanks,
> > > > > > Satish.
> > > > > >
> > > > > > On Tue, Nov 10, 2020 at 8:26 PM Satish Duggana <
> > > > satish.duggana@gmail.com>
> > > > > > wrote:
> > > > > > >
> > > > > > > Hi Jun,
> > > > > > > Thanks for your comments. Please find the inline replies below.
> > > > > > >
> > > > > > > 605.2 "Build the local leader epoch cache by cutting the leader
> > epoch
> > > > > > > sequence received from remote storage to [LSO, ELO]." I
> > mentioned an
> > > > > > issue
> > > > > > > earlier. Suppose the leader's local start offset is 100. The
> > follower
> > > > > > finds
> > > > > > > a remote segment covering offset range [80, 120). The
> > producerState
> > > > with
> > > > > > > this remote segment is up to offset 120. To trim the
> > producerState to
> > > > > > > offset 100 requires more work since one needs to download the
> > > > previous
> > > > > > > producerState up to offset 80 and then replay the messages from
> > 80 to
> > > > > > 100.
> > > > > > > It seems that it's simpler in this case for the follower just
> to
> > > > take the
> > > > > > > remote segment as it is and start fetching from offset 120.
> > > > > > >
> > > > > > > We chose that approach to avoid any edge cases here. It may be
> > > > > > > possible that the remote log segment that is received may not
> > have
> > > > the
> > > > > > > same leader epoch sequence from 100-120 as it contains on the
> > > > > > > leader(this can happen due to unclean leader). It is safe to
> > start
> > > > > > > from what the leader returns here.Another way is to find the
> > remote
> > > > > > > log segment
> > > > > > >
> > > > > > > 5016. Just to echo what Kowshik was saying. It seems that
> > > > > > > RLMM.onPartitionLeadershipChanges() is only called on the
> > replicas
> > > > for a
> > > > > > > partition, not on the replicas for the
> > __remote_log_segment_metadata
> > > > > > > partition. It's not clear how the leader of
> > > > __remote_log_segment_metadata
> > > > > > > obtains the metadata for remote segments for deletion.
> > > > > > >
> > > > > > > RLMM will always receive the callback for the remote log
> metadata
> > > > > > > topic partitions hosted on the local broker and these will be
> > > > > > > subscribed. I will make this clear in the KIP.
> > > > > > >
> > > > > > > 5100. KIP-516 has been accepted and is being implemented now.
> > Could
> > > > you
> > > > > > > update the KIP based on topicID?
> > > > > > >
> > > > > > > We mentioned KIP-516 and how it helps. We will update this KIP
> > with
> > > > > > > all the changes it brings with KIP-516.
> > > > > > >
> > > > > > > 5101. RLMM: It would be useful to clarify how the following two
> > APIs
> > > > are
> > > > > > > used. According to the wiki, the former is used for topic
> > deletion
> > > > and
> > > > > > the
> > > > > > > latter is used for retention. It seems that retention should
> use
> > the
> > > > > > former
> > > > > > > since remote segments without a matching epoch in the leader
> > > > (potentially
> > > > > > > due to unclean leader election) also need to be garbage
> > collected.
> > > > The
> > > > > > > latter seems to be used for the new leader to determine the
> last
> > > > tiered
> > > > > > > segment.
> > > > > > >     default Iterator<RemoteLogSegmentMetadata>
> > > > > > > listRemoteLogSegments(TopicPartition topicPartition)
> > > > > > >     Iterator<RemoteLogSegmentMetadata>
> > > > > > listRemoteLogSegments(TopicPartition
> > > > > > > topicPartition, long leaderEpoch);
> > > > > > >
> > > > > > > Right,.that is what we are currently doing. We will update the
> > > > > > > javadocs and wiki with that. Earlier, we did not want to remove
> > the
> > > > > > > segments which are not matched with leader epochs from the
> ladder
> > > > > > > partition as they may be used later by a replica which can
> > become a
> > > > > > > leader (unclean leader election) and refer those segments. But
> > that
> > > > > > > may leak these segments in remote storage until the topic
> > lifetime.
> > > > We
> > > > > > > decided to cleanup the segments with the oldest incase of size
> > based
> > > > > > > retention also.
> > > > > > >
> > > > > > > 5102. RSM:
> > > > > > > 5102.1 For methods like fetchLogSegmentData(), it seems that
> > they can
> > > > > > > use RemoteLogSegmentId instead of RemoteLogSegmentMetadata.
> > > > > > >
> > > > > > > It will be useful to have metadata for RSM to fetch log
> segment.
> > It
> > > > > > > may create location/path using id with other metadata too.
> > > > > > >
> > > > > > > 5102.2 In fetchLogSegmentData(), should we use long instead of
> > Long?
> > > > > > >
> > > > > > > Wanted to keep endPosition as optional to read till the end of
> > the
> > > > > > > segment and avoid sentinels.
> > > > > > >
> > > > > > > 5102.3 Why only some of the methods have default implementation
> > and
> > > > > > others
> > > > > > > Don't?
> > > > > > >
> > > > > > > Actually,  RSM will not have any default implementations.
> Those 3
> > > > > > > methods were made default earlier for tests etc. Updated the
> > wiki.
> > > > > > >
> > > > > > > 5102.4. Could we define RemoteLogSegmentMetadataUpdate
> > > > > > > and DeletePartitionUpdate?
> > > > > > >
> > > > > > > Sure, they will be added.
> > > > > > >
> > > > > > >
> > > > > > > 5102.5 LogSegmentData: It seems that it's easier to pass
> > > > > > > in leaderEpochIndex as a ByteBuffer or byte array than a file
> > since
> > > > it
> > > > > > will
> > > > > > > be generated in memory.
> > > > > > >
> > > > > > > Right, this is in plan.
> > > > > > >
> > > > > > > 5102.6 RemoteLogSegmentMetadata: It seems that it needs both
> > > > baseOffset
> > > > > > and
> > > > > > > startOffset. For example, deleteRecords() could move the
> > startOffset
> > > > to
> > > > > > the
> > > > > > > middle of a segment. If we copy the full segment to remote
> > storage,
> > > > the
> > > > > > > baseOffset and the startOffset will be different.
> > > > > > >
> > > > > > > Good point. startOffset is baseOffset by default, if not set
> > > > explicitly.
> > > > > > >
> > > > > > > 5102.7 Could we define all the public methods for
> > > > > > RemoteLogSegmentMetadata
> > > > > > > and LogSegmentData?
> > > > > > >
> > > > > > > Sure, updated the wiki.
> > > > > > >
> > > > > > > 5102.8 Could we document whether endOffset in
> > > > RemoteLogSegmentMetadata is
> > > > > > > inclusive/exclusive?
> > > > > > >
> > > > > > > It is inclusive, will update.
> > > > > > >
> > > > > > > 5103. configs:
> > > > > > > 5103.1 Could we define the default value of non-required
> configs
> > > > (e.g the
> > > > > > > size of new thread pools)?
> > > > > > >
> > > > > > > Sure, that makes sense.
> > > > > > >
> > > > > > > 5103.2 It seems that local.log.retention.ms should default to
> > > > > > retention.ms,
> > > > > > > instead of remote.log.retention.minutes. Similarly, it seems
> > > > > > > that local.log.retention.bytes should default to segment.bytes.
> > > > > > >
> > > > > > > Right, we do not have  remote.log.retention as we discussed
> > earlier.
> > > > > > > Thanks for catching the typo.
> > > > > > >
> > > > > > > 5103.3 remote.log.manager.thread.pool.size: The description
> says
> > > > "used in
> > > > > > > scheduling tasks to copy segments, fetch remote log indexes and
> > > > clean up
> > > > > > > remote log segments". However, there is a separate
> > > > > > > config remote.log.reader.threads for fetching remote data. It's
> > > > weird to
> > > > > > > fetch remote index and log in different thread pools since both
> > are
> > > > used
> > > > > > > for serving fetch requests.
> > > > > > >
> > > > > > > Right, remote.log.manager.thread.pool is mainly used for
> > copy/cleanup
> > > > > > > activities. Fetch path always goes through
> > remote.log.reader.threads.
> > > > > > >
> > > > > > > 5103.4 remote.log.manager.task.interval.ms: Is that the amount
> > of
> > > > time
> > > > > > to
> > > > > > > back off when there is no work to do? If so, perhaps it can be
> > > > renamed as
> > > > > > > backoff.ms.
> > > > > > >
> > > > > > > This is the delay interval for each iteration. It may be
> renamed
> > to
> > > > > > > remote.log.manager.task.delay.ms
> > > > > > >
> > > > > > > 5103.5 Are rlm_process_interval_ms and rlm_retry_interval_ms
> > > > configs? If
> > > > > > > so, they need to be listed in this section.
> > > > > > >
> > > > > > > remote.log.manager.task.interval.ms is the process internal,
> > retry
> > > > > > > interval is missing in the configs, which will be updated in
> the
> > KIP.
> > > > > > >
> > > > > > > 5104. "RLM maintains a bounded cache(possibly LRU) of the index
> > > > files of
> > > > > > > remote log segments to avoid multiple index fetches from the
> > remote
> > > > > > > storage." Is the RLM in memory or on disk? If on disk, where is
> > it
> > > > > > stored?
> > > > > > > Do we need a configuration to bound the size?
> > > > > > >
> > > > > > > It is stored on disk. They are stored in a directory
> > > > > > > `remote-log-index-cache` under log dir. We plan to have a
> config
> > for
> > > > > > > that instead of default. We will have a configuration for that.
> > > > > > >
> > > > > > > 5105. The KIP uses local-log-start-offset and Earliest Local
> > Offset
> > > > in
> > > > > > > different places. It would be useful to standardize the
> > terminology.
> > > > > > >
> > > > > > > Sure.
> > > > > > >
> > > > > > > 5106. The section on "In BuildingRemoteLogAux state". It listed
> > two
> > > > > > options
> > > > > > > without saying which option is chosen.
> > > > > > > We already mentioned in the KIP that we chose option-2.
> > > > > > >
> > > > > > > 5107. Follower to leader transition: It has step 2, but not
> step
> > 1.
> > > > > > > Step-1 is there but it is not explicitly highlighted. It is
> > previous
> > > > > > > table to step-2.
> > > > > > >
> > > > > > > 5108. If a consumer fetches from the remote data and the remote
> > > > storage
> > > > > > is
> > > > > > > not available, what error code is used in the fetch response?
> > > > > > >
> > > > > > > Good point. We have not yet defined the error for this case. We
> > need
> > > > > > > to define an error message and send the same in fetch response.
> > > > > > >
> > > > > > > 5109. "ListOffsets: For timestamps >= 0, it returns the first
> > message
> > > > > > > offset whose timestamp is >= to the given timestamp in the
> > request.
> > > > That
> > > > > > > means it checks in remote log time indexes first, after which
> > local
> > > > log
> > > > > > > time indexes are checked." Could you document which method in
> > RLMM is
> > > > > > used
> > > > > > > for this?
> > > > > > >
> > > > > > > Okay.
> > > > > > >
> > > > > > > 5110. Stopreplica: "it sets all the remote log segment metadata
> > of
> > > > that
> > > > > > > partition with a delete marker and publishes them to RLMM."
> This
> > > > seems
> > > > > > > outdated given the new topic deletion logic.
> > > > > > >
> > > > > > > Will update with KIP-516 related points.
> > > > > > >
> > > > > > > 5111. "RLM follower fetches the earliest offset for the
> earliest
> > > > leader
> > > > > > > epoch by calling RLMM.earliestLogOffset(TopicPartition
> > > > topicPartition,
> > > > > > int
> > > > > > > leaderEpoch) and updates that as the log start offset." Do we
> > need
> > > > that
> > > > > > > since replication propagates logStartOffset already?
> > > > > > >
> > > > > > > Good point. Right, existing replication protocol takes care of
> > > > > > > updating the followers’s log start offset received from the
> > leader.
> > > > > > >
> > > > > > > 5112. Is the default maxWaitMs of 500ms enough for fetching
> from
> > > > remote
> > > > > > > storage?
> > > > > > >
> > > > > > > Remote reads may fail within the current default wait time, but
> > > > > > > subsequent fetches would be able to serve as that data is
> stored
> > in
> > > > > > > the local cache. This cache is currently implemented in RSMs.
> > But we
> > > > > > > plan to pull this into the remote log messaging layer in
> future.
> > > > > > >
> > > > > > > 5113. "Committed offsets can be stored in a local file to avoid
> > > > reading
> > > > > > the
> > > > > > > messages again when a broker is restarted." Could you describe
> > the
> > > > format
> > > > > > > and the location of the file? Also, could the same message be
> > > > processed
> > > > > > by
> > > > > > > RLMM again after broker restart? If so, how do we handle that?
> > > > > > >
> > > > > > > Sure, we will update in the KIP.
> > > > > > >
> > > > > > > 5114. Message format
> > > > > > > 5114.1 There are two records named
> RemoteLogSegmentMetadataRecord
> > > > with
> > > > > > > apiKey 0 and 1.
> > > > > > >
> > > > > > > Nice catch, that was a typo. Fixed in the wiki.
> > > > > > >
> > > > > > > 5114.2 RemoteLogSegmentMetadataRecord: Could we document
> whether
> > > > > > endOffset
> > > > > > > is inclusive/exclusive?
> > > > > > > It is inclusive, will update.
> > > > > > >
> > > > > > > 5114.3 RemoteLogSegmentMetadataRecord: Could you explain
> > LeaderEpoch
> > > > a
> > > > > > bit
> > > > > > > more? Is that the epoch of the leader when it copies the
> segment
> > to
> > > > > > remote
> > > > > > > storage? Also, how will this field be used?
> > > > > > >
> > > > > > > Right, this is the leader epoch of the broker which copied this
> > > > > > > segment. This is helpful in reason about which broker copied
> the
> > > > > > > segment to remote storage.
> > > > > > >
> > > > > > > 5114.4 EventTimestamp: Could you explain this a bit more? Each
> > > > record in
> > > > > > > Kafka already has a timestamp field. Could we just use that?
> > > > > > >
> > > > > > > This is the  timestamp at which  the respective event occurred.
> > Added
> > > > > > > this  to RemoteLogSegmentMetadata as RLMM can be  any other
> > > > > > > implementation. We thought about that but it looked cleaner to
> > use at
> > > > > > > the message structure level instead of getting that from the
> > consumer
> > > > > > > record and using that to build the respective event.
> > > > > > >
> > > > > > >
> > > > > > > 5114.5 SegmentSizeInBytes: Could this just be int32?
> > > > > > >
> > > > > > > Right, it looks like config allows only int value >= 14.
> > > > > > >
> > > > > > > 5115. RemoteLogCleaner(RLC): This could be confused with the
> log
> > > > cleaner
> > > > > > > for compaction. Perhaps it can be renamed to sth like
> > > > > > > RemotePartitionRemover.
> > > > > > >
> > > > > > > I am fine with RemotePartitionRemover or
> > RemoteLogDeletionManager(we
> > > > > > > have other manager classes like RLM, RLMM).
> > > > > > >
> > > > > > > 5116. "RLC receives the delete_partition_marked and processes
> it
> > if
> > > > it is
> > > > > > > not yet processed earlier." How does it know whether
> > > > > > > delete_partition_marked has been processed earlier?
> > > > > > >
> > > > > > > This is to handle duplicate delete_partition_marked events. RLC
> > > > > > > internally maintains a state for the delete_partition events
> and
> > if
> > > > it
> > > > > > > already has an existing event then it ignores if it is already
> > being
> > > > > > > processed.
> > > > > > >
> > > > > > > 5117. Should we add a new MessageFormatter to read the tier
> > metadata
> > > > > > topic?
> > > > > > >
> > > > > > > Right, this is in plan but did not mention it in the KIP. This
> > will
> > > > be
> > > > > > > useful for debugging purposes too.
> > > > > > >
> > > > > > > 5118. "Maximum remote log reader thread pool task queue size.
> If
> > the
> > > > task
> > > > > > > queue is full, broker will stop reading remote log segments."
> > What
> > > > do we
> > > > > > > return to the fetch request in this case?
> > > > > > >
> > > > > > > We return an error response for that partition.
> > > > > > >
> > > > > > > 5119. It would be useful to list all things not supported in
> the
> > > > first
> > > > > > > version in a Future work or Limitations section. For example,
> > > > compacted
> > > > > > > topic, JBOD, changing remote.log.storage.enable from true to
> > false,
> > > > etc.
> > > > > > >
> > > > > > > We already have a non-goals section which is filled with some
> of
> > > > these
> > > > > > > details. Do we need another limitations section?
> > > > > > >
> > > > > > > Thanks,
> > > > > > > Satish.
> > > > > > >
> > > > > > > On Wed, Nov 4, 2020 at 11:27 PM Jun Rao <ju...@confluent.io>
> > wrote:
> > > > > > > >
> > > > > > > > Hi, Satish,
> > > > > > > >
> > > > > > > > Thanks for the updated KIP. A few more comments below.
> > > > > > > >
> > > > > > > > 605.2 "Build the local leader epoch cache by cutting the
> leader
> > > > epoch
> > > > > > > > sequence received from remote storage to [LSO, ELO]." I
> > mentioned
> > > > an
> > > > > > issue
> > > > > > > > earlier. Suppose the leader's local start offset is 100. The
> > > > follower
> > > > > > finds
> > > > > > > > a remote segment covering offset range [80, 120). The
> > producerState
> > > > > > with
> > > > > > > > this remote segment is up to offset 120. To trim the
> > producerState
> > > > to
> > > > > > > > offset 100 requires more work since one needs to download the
> > > > previous
> > > > > > > > producerState up to offset 80 and then replay the messages
> > from 80
> > > > to
> > > > > > 100.
> > > > > > > > It seems that it's simpler in this case for the follower just
> > to
> > > > take
> > > > > > the
> > > > > > > > remote segment as it is and start fetching from offset 120.
> > > > > > > >
> > > > > > > > 5016. Just to echo what Kowshik was saying. It seems that
> > > > > > > > RLMM.onPartitionLeadershipChanges() is only called on the
> > replicas
> > > > for
> > > > > > a
> > > > > > > > partition, not on the replicas for the
> > > > __remote_log_segment_metadata
> > > > > > > > partition. It's not clear how the leader of
> > > > > > __remote_log_segment_metadata
> > > > > > > > obtains the metadata for remote segments for deletion.
> > > > > > > >
> > > > > > > > 5100. KIP-516 has been accepted and is being implemented now.
> > > > Could you
> > > > > > > > update the KIP based on topicID?
> > > > > > > >
> > > > > > > > 5101. RLMM: It would be useful to clarify how the following
> two
> > > > APIs
> > > > > > are
> > > > > > > > used. According to the wiki, the former is used for topic
> > deletion
> > > > and
> > > > > > the
> > > > > > > > latter is used for retention. It seems that retention should
> > use
> > > > the
> > > > > > former
> > > > > > > > since remote segments without a matching epoch in the leader
> > > > > > (potentially
> > > > > > > > due to unclean leader election) also need to be garbage
> > collected.
> > > > The
> > > > > > > > latter seems to be used for the new leader to determine the
> > last
> > > > tiered
> > > > > > > > segment.
> > > > > > > >     default Iterator<RemoteLogSegmentMetadata>
> > > > > > > > listRemoteLogSegments(TopicPartition topicPartition)
> > > > > > > >     Iterator<RemoteLogSegmentMetadata>
> > > > > > listRemoteLogSegments(TopicPartition
> > > > > > > > topicPartition, long leaderEpoch);
> > > > > > > >
> > > > > > > > 5102. RSM:
> > > > > > > > 5102.1 For methods like fetchLogSegmentData(), it seems that
> > they
> > > > can
> > > > > > > > use RemoteLogSegmentId instead of RemoteLogSegmentMetadata.
> > > > > > > > 5102.2 In fetchLogSegmentData(), should we use long instead
> of
> > > > Long?
> > > > > > > > 5102.3 Why only some of the methods have default
> > implementation and
> > > > > > others
> > > > > > > > don't?
> > > > > > > > 5102.4. Could we define RemoteLogSegmentMetadataUpdate
> > > > > > > > and DeletePartitionUpdate?
> > > > > > > > 5102.5 LogSegmentData: It seems that it's easier to pass
> > > > > > > > in leaderEpochIndex as a ByteBuffer or byte array than a file
> > > > since it
> > > > > > will
> > > > > > > > be generated in memory.
> > > > > > > > 5102.6 RemoteLogSegmentMetadata: It seems that it needs both
> > > > > > baseOffset and
> > > > > > > > startOffset. For example, deleteRecords() could move the
> > > > startOffset
> > > > > > to the
> > > > > > > > middle of a segment. If we copy the full segment to remote
> > > > storage, the
> > > > > > > > baseOffset and the startOffset will be different.
> > > > > > > > 5102.7 Could we define all the public methods for
> > > > > > RemoteLogSegmentMetadata
> > > > > > > > and LogSegmentData?
> > > > > > > > 5102.8 Could we document whether endOffset in
> > > > RemoteLogSegmentMetadata
> > > > > > is
> > > > > > > > inclusive/exclusive?
> > > > > > > >
> > > > > > > > 5103. configs:
> > > > > > > > 5103.1 Could we define the default value of non-required
> > configs
> > > > (e.g
> > > > > > the
> > > > > > > > size of new thread pools)?
> > > > > > > > 5103.2 It seems that local.log.retention.ms should default
> to
> > > > > > retention.ms,
> > > > > > > > instead of remote.log.retention.minutes. Similarly, it seems
> > > > > > > > that local.log.retention.bytes should default to
> segment.bytes.
> > > > > > > > 5103.3 remote.log.manager.thread.pool.size: The description
> > says
> > > > "used
> > > > > > in
> > > > > > > > scheduling tasks to copy segments, fetch remote log indexes
> and
> > > > clean
> > > > > > up
> > > > > > > > remote log segments". However, there is a separate
> > > > > > > > config remote.log.reader.threads for fetching remote data.
> It's
> > > > weird
> > > > > > to
> > > > > > > > fetch remote index and log in different thread pools since
> > both are
> > > > > > used
> > > > > > > > for serving fetch requests.
> > > > > > > > 5103.4 remote.log.manager.task.interval.ms: Is that the
> > amount of
> > > > > > time to
> > > > > > > > back off when there is no work to do? If so, perhaps it can
> be
> > > > renamed
> > > > > > as
> > > > > > > > backoff.ms.
> > > > > > > > 5103.5 Are rlm_process_interval_ms and rlm_retry_interval_ms
> > > > configs?
> > > > > > If
> > > > > > > > so, they need to be listed in this section.
> > > > > > > >
> > > > > > > > 5104. "RLM maintains a bounded cache(possibly LRU) of the
> index
> > > > files
> > > > > > of
> > > > > > > > remote log segments to avoid multiple index fetches from the
> > remote
> > > > > > > > storage." Is the RLM in memory or on disk? If on disk, where
> > is it
> > > > > > stored?
> > > > > > > > Do we need a configuration to bound the size?
> > > > > > > >
> > > > > > > > 5105. The KIP uses local-log-start-offset and Earliest Local
> > > > Offset in
> > > > > > > > different places. It would be useful to standardize the
> > > > terminology.
> > > > > > > >
> > > > > > > > 5106. The section on "In BuildingRemoteLogAux state". It
> > listed two
> > > > > > options
> > > > > > > > without saying which option is chosen.
> > > > > > > >
> > > > > > > > 5107. Follower to leader transition: It has step 2, but not
> > step 1.
> > > > > > > >
> > > > > > > > 5108. If a consumer fetches from the remote data and the
> remote
> > > > > > storage is
> > > > > > > > not available, what error code is used in the fetch response?
> > > > > > > >
> > > > > > > > 5109. "ListOffsets: For timestamps >= 0, it returns the first
> > > > message
> > > > > > > > offset whose timestamp is >= to the given timestamp in the
> > request.
> > > > > > That
> > > > > > > > means it checks in remote log time indexes first, after which
> > > > local log
> > > > > > > > time indexes are checked." Could you document which method in
> > RLMM
> > > > is
> > > > > > used
> > > > > > > > for this?
> > > > > > > >
> > > > > > > > 5110. Stopreplica: "it sets all the remote log segment
> > metadata of
> > > > that
> > > > > > > > partition with a delete marker and publishes them to RLMM."
> > This
> > > > seems
> > > > > > > > outdated given the new topic deletion logic.
> > > > > > > >
> > > > > > > > 5111. "RLM follower fetches the earliest offset for the
> > earliest
> > > > leader
> > > > > > > > epoch by calling RLMM.earliestLogOffset(TopicPartition
> > > > topicPartition,
> > > > > > int
> > > > > > > > leaderEpoch) and updates that as the log start offset." Do we
> > need
> > > > that
> > > > > > > > since replication propagates logStartOffset already?
> > > > > > > >
> > > > > > > > 5112. Is the default maxWaitMs of 500ms enough for fetching
> > from
> > > > remote
> > > > > > > > storage?
> > > > > > > >
> > > > > > > > 5113. "Committed offsets can be stored in a local file to
> avoid
> > > > > > reading the
> > > > > > > > messages again when a broker is restarted." Could you
> describe
> > the
> > > > > > format
> > > > > > > > and the location of the file? Also, could the same message be
> > > > > > processed by
> > > > > > > > RLMM again after broker restart? If so, how do we handle
> that?
> > > > > > > >
> > > > > > > > 5114. Message format
> > > > > > > > 5114.1 There are two records named
> > RemoteLogSegmentMetadataRecord
> > > > with
> > > > > > > > apiKey 0 and 1.
> > > > > > > > 5114.2 RemoteLogSegmentMetadataRecord: Could we document
> > whether
> > > > > > endOffset
> > > > > > > > is inclusive/exclusive?
> > > > > > > > 5114.3 RemoteLogSegmentMetadataRecord: Could you explain
> > > > LeaderEpoch a
> > > > > > bit
> > > > > > > > more? Is that the epoch of the leader when it copies the
> > segment to
> > > > > > remote
> > > > > > > > storage? Also, how will this field be used?
> > > > > > > > 5114.4 EventTimestamp: Could you explain this a bit more?
> Each
> > > > record
> > > > > > in
> > > > > > > > Kafka already has a timestamp field. Could we just use that?
> > > > > > > > 5114.5 SegmentSizeInBytes: Could this just be int32?
> > > > > > > >
> > > > > > > > 5115. RemoteLogCleaner(RLC): This could be confused with the
> > log
> > > > > > cleaner
> > > > > > > > for compaction. Perhaps it can be renamed to sth like
> > > > > > > > RemotePartitionRemover.
> > > > > > > >
> > > > > > > > 5116. "RLC receives the delete_partition_marked and processes
> > it
> > > > if it
> > > > > > is
> > > > > > > > not yet processed earlier." How does it know whether
> > > > > > > > delete_partition_marked has been processed earlier?
> > > > > > > >
> > > > > > > > 5117. Should we add a new MessageFormatter to read the tier
> > > > metadata
> > > > > > topic?
> > > > > > > >
> > > > > > > > 5118. "Maximum remote log reader thread pool task queue size.
> > If
> > > > the
> > > > > > task
> > > > > > > > queue is full, broker will stop reading remote log segments."
> > What
> > > > do
> > > > > > we
> > > > > > > > return to the fetch request in this case?
> > > > > > > >
> > > > > > > > 5119. It would be useful to list all things not supported in
> > the
> > > > first
> > > > > > > > version in a Future work or Limitations section. For example,
> > > > compacted
> > > > > > > > topic, JBOD, changing remote.log.storage.enable from true to
> > false,
> > > > > > etc.
> > > > > > > >
> > > > > > > > Thanks,
> > > > > > > >
> > > > > > > > Jun
> > > > > > > >
> > > > > > > > On Tue, Oct 27, 2020 at 5:57 PM Kowshik Prakasam <
> > > > > > kprakasam@confluent.io>
> > > > > > > > wrote:
> > > > > > > >
> > > > > > > > > Hi Satish,
> > > > > > > > >
> > > > > > > > > Thanks for the updates to the KIP. Here are my first batch
> of
> > > > > > > > > comments/suggestions on the latest version of the KIP.
> > > > > > > > >
> > > > > > > > > 5012. In the RemoteStorageManager interface, there is an
> API
> > > > defined
> > > > > > for
> > > > > > > > > each file type. For example, fetchOffsetIndex,
> > > > fetchTimestampIndex
> > > > > > etc. To
> > > > > > > > > avoid the duplication, I'd suggest we can instead have a
> > FileType
> > > > > > enum and
> > > > > > > > > a common get API based on the FileType.
> > > > > > > > >
> > > > > > > > > 5013. There are some references to the Google doc in the
> > KIP. I
> > > > > > wasn't sure
> > > > > > > > > if the Google doc is expected to be in sync with the
> > contents of
> > > > the
> > > > > > wiki.
> > > > > > > > > Going forward, it seems easier if just the KIP is
> maintained
> > as
> > > > the
> > > > > > source
> > > > > > > > > of truth. In this regard, could you please move all the
> > > > references
> > > > > > to the
> > > > > > > > > Google doc, maybe to a separate References section at the
> > bottom
> > > > of
> > > > > > the
> > > > > > > > > KIP?
> > > > > > > > >
> > > > > > > > > 5014. There are some TODO sections in the KIP. Would these
> be
> > > > filled
> > > > > > up in
> > > > > > > > > future iterations?
> > > > > > > > >
> > > > > > > > > 5015. Under "Topic deletion lifecycle", I'm trying to
> > understand
> > > > why
> > > > > > do we
> > > > > > > > > need delete_partition_marked as well as the
> > > > delete_partition_started
> > > > > > > > > messages. I couldn't spot a drawback if supposing we
> > simplified
> > > > the
> > > > > > design
> > > > > > > > > such that the controller would only write
> > > > delete_partition_started
> > > > > > message,
> > > > > > > > > and RemoteLogCleaner (RLC) instance picks it up for
> > processing.
> > > > What
> > > > > > am I
> > > > > > > > > missing?
> > > > > > > > >
> > > > > > > > > 5016. Under "Topic deletion lifecycle", step (4) is
> > mentioned as
> > > > > > "RLC gets
> > > > > > > > > all the remote log segments for the partition and each of
> > these
> > > > > > remote log
> > > > > > > > > segments is deleted with the next steps.". Since the RLC
> > instance
> > > > > > runs on
> > > > > > > > > each tier topic partition leader, how does the RLC then get
> > the
> > > > list
> > > > > > of
> > > > > > > > > remote log segments to be deleted? It will be useful to add
> > that
> > > > > > detail to
> > > > > > > > > the KIP.
> > > > > > > > >
> > > > > > > > > 5017. Under "Public Interfaces -> Configs", there is a line
> > > > > > mentioning "We
> > > > > > > > > will support flipping remote.log.storage.enable in next
> > > > versions."
> > > > > > It will
> > > > > > > > > be useful to mention this in the "Future Work" section of
> > the KIP
> > > > > > too.
> > > > > > > > >
> > > > > > > > > 5018. The KIP introduces a number of configuration
> > parameters. It
> > > > > > will be
> > > > > > > > > useful to mention in the KIP if the user should assume
> these
> > as
> > > > > > static
> > > > > > > > > configuration in the server.properties file, or dynamic
> > > > > > configuration which
> > > > > > > > > can be modified without restarting the broker.
> > > > > > > > >
> > > > > > > > > 5019.  Maybe this is planned as a future update to the KIP,
> > but I
> > > > > > thought
> > > > > > > > > I'd mention it here. Could you please add details to the
> KIP
> > on
> > > > why
> > > > > > RocksDB
> > > > > > > > > was chosen as the default cache implementation of RLMM, and
> > how
> > > > it
> > > > > > is going
> > > > > > > > > to be used? Were alternatives compared/considered? For
> > example,
> > > > it
> > > > > > would be
> > > > > > > > > useful to explain/evaluate the following: 1) debuggability
> > of the
> > > > > > RocksDB
> > > > > > > > > JNI interface, 2) performance, 3) portability across
> > platforms
> > > > and 4)
> > > > > > > > > interface parity of RocksDB’s JNI api with it's underlying
> > C/C++
> > > > api.
> > > > > > > > >
> > > > > > > > > 5020. Following up on (5019), for the RocksDB cache, it
> will
> > be
> > > > > > useful to
> > > > > > > > > explain the relationship/mapping between the following in
> the
> > > > KIP:
> > > > > > 1) # of
> > > > > > > > > tiered partitions, 2) # of partitions of metadata topic
> > > > > > > > > __remote_log_metadata and 3) # of RocksDB instances. i.e.
> is
> > the
> > > > > > plan to
> > > > > > > > > have a RocksDB instance per tiered partition, or per
> metadata
> > > > topic
> > > > > > > > > partition, or just 1 for per broker?
> > > > > > > > >
> > > > > > > > > 5021. I was looking at the implementation prototype (PR
> link:
> > > > > > > > > https://github.com/apache/kafka/pull/7561). It seems that
> a
> > > > boolean
> > > > > > > > > attribute is being introduced into the Log layer to check
> if
> > > > remote
> > > > > > log
> > > > > > > > > capability is enabled. While the boolean footprint is small
> > at
> > > > the
> > > > > > moment,
> > > > > > > > > this can easily grow in the future and become harder to
> > > > > > > > > test/maintain, considering that the Log layer is already
> > pretty
> > > > > > complex. We
> > > > > > > > > should start thinking about how to manage such changes to
> > the Log
> > > > > > layer
> > > > > > > > > (for the purpose of improved testability, better separation
> > of
> > > > > > concerns and
> > > > > > > > > readability). One proposal I have is to take a step back
> and
> > > > define a
> > > > > > > > > higher level Log interface. Then, the Broker code can be
> > changed
> > > > to
> > > > > > use
> > > > > > > > > this interface. It can be changed such that only a handle
> to
> > the
> > > > > > interface
> > > > > > > > > is exposed to other components (such as LogCleaner,
> > > > ReplicaManager
> > > > > > etc.)
> > > > > > > > > and not the underlying Log object. This approach keeps the
> > user
> > > > of
> > > > > > the Log
> > > > > > > > > layer agnostic of the whereabouts of the data. Underneath
> the
> > > > > > interface,
> > > > > > > > > the implementing classes can completely separate local log
> > > > > > capabilities
> > > > > > > > > from the remote log. For example, the Log class can be
> > > > simplified to
> > > > > > only
> > > > > > > > > manage logic surrounding local log segments and metadata.
> > > > > > Additionally, a
> > > > > > > > > wrapper class can be provided (implementing the higher
> level
> > Log
> > > > > > interface)
> > > > > > > > > which will contain any/all logic surrounding tiered data.
> The
> > > > wrapper
> > > > > > > > > class will wrap around an instance of the Log class
> > delegating
> > > > the
> > > > > > local
> > > > > > > > > log logic to it. Finally, a handle to the wrapper class can
> > be
> > > > > > exposed to
> > > > > > > > > the other components wherever they need a handle to the
> > higher
> > > > level
> > > > > > Log
> > > > > > > > > interface.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > Cheers,
> > > > > > > > > Kowshik
> > > > > > > > >
> > > > > > > > > On Mon, Oct 26, 2020 at 9:52 PM Satish Duggana <
> > > > > > satish.duggana@gmail.com>
> > > > > > > > > wrote:
> > > > > > > > >
> > > > > > > > > > Hi,
> > > > > > > > > > KIP is updated with 1) topic deletion lifecycle and its
> > related
> > > > > > items
> > > > > > > > > > 2) Protocol changes(mainly related to ListOffsets) and
> > other
> > > > minor
> > > > > > > > > > changes.
> > > > > > > > > > Please go through them and let us know your comments.
> > > > > > > > > >
> > > > > > > > > > Thanks,
> > > > > > > > > > Satish.
> > > > > > > > > >
> > > > > > > > > > On Mon, Sep 28, 2020 at 9:10 PM Satish Duggana <
> > > > > > satish.duggana@gmail.com
> > > > > > > > > >
> > > > > > > > > > wrote:
> > > > > > > > > > >
> > > > > > > > > > > Hi Dhruvil,
> > > > > > > > > > > Thanks for looking into the KIP and sending your
> > comments.
> > > > Sorry
> > > > > > for
> > > > > > > > > > > the late reply, missed it in the mail thread.
> > > > > > > > > > >
> > > > > > > > > > > 1. Could you describe how retention would work with
> this
> > KIP
> > > > and
> > > > > > which
> > > > > > > > > > > threads are responsible for driving this work? I
> believe
> > > > there
> > > > > > are 3
> > > > > > > > > > kinds
> > > > > > > > > > > of retention processes we are looking at:
> > > > > > > > > > >   (a) Regular retention for data in tiered storage as
> per
> > > > > > configured `
> > > > > > > > > > > retention.ms` / `retention.bytes`.
> > > > > > > > > > >   (b) Local retention for data in local storage as per
> > > > > > configured `
> > > > > > > > > > > local.log.retention.ms` / `local.log.retention.bytes`
> > > > > > > > > > >   (c) Possibly regular retention for data in local
> > storage,
> > > > if
> > > > > > the
> > > > > > > > > > tiering
> > > > > > > > > > > task is lagging or for data that is below the log start
> > > > offset.
> > > > > > > > > > >
> > > > > > > > > > > Local log retention is done by the existing log cleanup
> > > > tasks.
> > > > > > These
> > > > > > > > > > > are not done for segments that are not yet copied to
> > remote
> > > > > > storage.
> > > > > > > > > > > Remote log cleanup is done by the leader partition’s
> > RLMTask.
> > > > > > > > > > >
> > > > > > > > > > > 2. When does a segment become eligible to be tiered? Is
> > it as
> > > > > > soon as
> > > > > > > > > the
> > > > > > > > > > > segment is rolled and the end offset is less than the
> > last
> > > > stable
> > > > > > > > > offset
> > > > > > > > > > as
> > > > > > > > > > > mentioned in the KIP? I wonder if we need to consider
> > other
> > > > > > parameters
> > > > > > > > > > too,
> > > > > > > > > > > like the highwatermark so that we are guaranteed that
> > what
> > > > we are
> > > > > > > > > tiering
> > > > > > > > > > > has been committed to the log and accepted by the ISR.
> > > > > > > > > > >
> > > > > > > > > > > AFAIK, last stable offset is always <= highwatermark.
> > This
> > > > will
> > > > > > make
> > > > > > > > > > > sure we are always tiering the message segments which
> > have
> > > > been
> > > > > > > > > > > accepted by ISR and transactionally completed.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > 3. The section on "Follower Fetch Scenarios" is useful
> > but
> > > > is a
> > > > > > bit
> > > > > > > > > > > difficult to parse at the moment. It would be useful to
> > > > > > summarize the
> > > > > > > > > > > changes we need in the ReplicaFetcher.
> > > > > > > > > > >
> > > > > > > > > > > It may become difficult for users to read/follow if we
> > add
> > > > code
> > > > > > changes
> > > > > > > > > > here.
> > > > > > > > > > >
> > > > > > > > > > > 4. Related to the above, it's a bit unclear how we are
> > > > planning
> > > > > > on
> > > > > > > > > > > restoring the producer state for a new replica. Could
> you
> > > > expand
> > > > > > on
> > > > > > > > > that?
> > > > > > > > > > >
> > > > > > > > > > > It is mentioned in the KIP BuildingRemoteLogAuxState is
> > > > > > introduced to
> > > > > > > > > > > build the state like leader epoch sequence and producer
> > > > snapshots
> > > > > > > > > > > before it starts fetching the data from the leader. We
> > will
> > > > make
> > > > > > it
> > > > > > > > > > > clear in the KIP.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > 5. Similarly, it would be worth summarizing the
> behavior
> > on
> > > > > > unclean
> > > > > > > > > > leader
> > > > > > > > > > > election. There are several scenarios to consider here:
> > data
> > > > > > loss from
> > > > > > > > > > > local log, data loss from remote log, data loss from
> > metadata
> > > > > > topic,
> > > > > > > > > etc.
> > > > > > > > > > > It's worth describing these in detail.
> > > > > > > > > > >
> > > > > > > > > > > We mentioned the cases about unclean leader election in
> > the
> > > > > > follower
> > > > > > > > > > > fetch scenarios.
> > > > > > > > > > > If there are errors while fetching data from remote
> > store or
> > > > > > metadata
> > > > > > > > > > > store, it will work the same way as it works with local
> > log.
> > > > It
> > > > > > > > > > > returns the error back to the caller. Please let us
> know
> > if
> > > > I am
> > > > > > > > > > > missing your point here.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > 7. For a READ_COMMITTED FetchRequest, how do we
> retrieve
> > and
> > > > > > return the
> > > > > > > > > > > aborted transaction metadata?
> > > > > > > > > > >
> > > > > > > > > > > When a fetch for a remote log is accessed, we will
> fetch
> > > > aborted
> > > > > > > > > > > transactions along with the segment if it is not found
> > in the
> > > > > > local
> > > > > > > > > > > index cache. This includes the case of transaction
> index
> > not
> > > > > > existing
> > > > > > > > > > > in the remote log segment. That means, the cache entry
> > can be
> > > > > > empty or
> > > > > > > > > > > have a list of aborted transactions.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > 8. The `LogSegmentData` class assumes that we have a
> log
> > > > segment,
> > > > > > > > > offset
> > > > > > > > > > > index, time index, transaction index, producer snapshot
> > and
> > > > > > leader
> > > > > > > > > epoch
> > > > > > > > > > > index. How do we deal with cases where we do not have
> > one or
> > > > > > more of
> > > > > > > > > > these?
> > > > > > > > > > > For example, we may not have a transaction index or
> > producer
> > > > > > snapshot
> > > > > > > > > > for a
> > > > > > > > > > > particular segment. The former is optional, and the
> > latter is
> > > > > > only kept
> > > > > > > > > > for
> > > > > > > > > > > up to the 3 latest segments.
> > > > > > > > > > >
> > > > > > > > > > > This is a good point,  we discussed this in the last
> > meeting.
> > > > > > > > > > > Transaction index is optional and we will copy them
> only
> > if
> > > > it
> > > > > > exists.
> > > > > > > > > > > We want to keep all the producer snapshots at each log
> > > > segment
> > > > > > rolling
> > > > > > > > > > > and they can be removed if the log copying is
> successful
> > and
> > > > it
> > > > > > still
> > > > > > > > > > > maintains the existing latest 3 segments, We only
> delete
> > the
> > > > > > producer
> > > > > > > > > > > snapshots which have been copied to remote log segments
> > on
> > > > > > leader.
> > > > > > > > > > > Follower will keep the log segments beyond the segments
> > which
> > > > > > have not
> > > > > > > > > > > been copied to remote storage. We will update the KIP
> > with
> > > > these
> > > > > > > > > > > details.
> > > > > > > > > > >
> > > > > > > > > > > Thanks,
> > > > > > > > > > > Satish.
> > > > > > > > > > >
> > > > > > > > > > > On Thu, Sep 17, 2020 at 1:47 AM Dhruvil Shah <
> > > > > > dhruvil@confluent.io>
> > > > > > > > > > wrote:
> > > > > > > > > > > >
> > > > > > > > > > > > Hi Satish, Harsha,
> > > > > > > > > > > >
> > > > > > > > > > > > Thanks for the KIP. Few questions below:
> > > > > > > > > > > >
> > > > > > > > > > > > 1. Could you describe how retention would work with
> > this
> > > > KIP
> > > > > > and
> > > > > > > > > which
> > > > > > > > > > > > threads are responsible for driving this work? I
> > believe
> > > > there
> > > > > > are 3
> > > > > > > > > > kinds
> > > > > > > > > > > > of retention processes we are looking at:
> > > > > > > > > > > >   (a) Regular retention for data in tiered storage as
> > per
> > > > > > configured
> > > > > > > > > `
> > > > > > > > > > > > retention.ms` / `retention.bytes`.
> > > > > > > > > > > >   (b) Local retention for data in local storage as
> per
> > > > > > configured `
> > > > > > > > > > > > local.log.retention.ms` /
> `local.log.retention.bytes`
> > > > > > > > > > > >   (c) Possibly regular retention for data in local
> > > > storage, if
> > > > > > the
> > > > > > > > > > tiering
> > > > > > > > > > > > task is lagging or for data that is below the log
> start
> > > > offset.
> > > > > > > > > > > >
> > > > > > > > > > > > 2. When does a segment become eligible to be tiered?
> > Is it
> > > > as
> > > > > > soon as
> > > > > > > > > > the
> > > > > > > > > > > > segment is rolled and the end offset is less than the
> > last
> > > > > > stable
> > > > > > > > > > offset as
> > > > > > > > > > > > mentioned in the KIP? I wonder if we need to consider
> > other
> > > > > > > > > parameters
> > > > > > > > > > too,
> > > > > > > > > > > > like the highwatermark so that we are guaranteed that
> > what
> > > > we
> > > > > > are
> > > > > > > > > > tiering
> > > > > > > > > > > > has been committed to the log and accepted by the
> ISR.
> > > > > > > > > > > >
> > > > > > > > > > > > 3. The section on "Follower Fetch Scenarios" is
> useful
> > but
> > > > is
> > > > > > a bit
> > > > > > > > > > > > difficult to parse at the moment. It would be useful
> to
> > > > > > summarize the
> > > > > > > > > > > > changes we need in the ReplicaFetcher.
> > > > > > > > > > > >
> > > > > > > > > > > > 4. Related to the above, it's a bit unclear how we
> are
> > > > > > planning on
> > > > > > > > > > > > restoring the producer state for a new replica. Could
> > you
> > > > > > expand on
> > > > > > > > > > that?
> > > > > > > > > > > >
> > > > > > > > > > > > 5. Similarly, it would be worth summarizing the
> > behavior on
> > > > > > unclean
> > > > > > > > > > leader
> > > > > > > > > > > > election. There are several scenarios to consider
> here:
> > > > data
> > > > > > loss
> > > > > > > > > from
> > > > > > > > > > > > local log, data loss from remote log, data loss from
> > > > metadata
> > > > > > topic,
> > > > > > > > > > etc.
> > > > > > > > > > > > It's worth describing these in detail.
> > > > > > > > > > > >
> > > > > > > > > > > > 6. It would be useful to add details about how we
> plan
> > on
> > > > using
> > > > > > > > > > RocksDB in
> > > > > > > > > > > > the default implementation of
> > `RemoteLogMetadataManager`.
> > > > > > > > > > > >
> > > > > > > > > > > > 7. For a READ_COMMITTED FetchRequest, how do we
> > retrieve
> > > > and
> > > > > > return
> > > > > > > > > the
> > > > > > > > > > > > aborted transaction metadata?
> > > > > > > > > > > >
> > > > > > > > > > > > 8. The `LogSegmentData` class assumes that we have a
> > log
> > > > > > segment,
> > > > > > > > > > offset
> > > > > > > > > > > > index, time index, transaction index, producer
> > snapshot and
> > > > > > leader
> > > > > > > > > > epoch
> > > > > > > > > > > > index. How do we deal with cases where we do not have
> > one
> > > > or
> > > > > > more of
> > > > > > > > > > these?
> > > > > > > > > > > > For example, we may not have a transaction index or
> > > > producer
> > > > > > snapshot
> > > > > > > > > > for a
> > > > > > > > > > > > particular segment. The former is optional, and the
> > latter
> > > > is
> > > > > > only
> > > > > > > > > > kept for
> > > > > > > > > > > > up to the 3 latest segments.
> > > > > > > > > > > >
> > > > > > > > > > > > Thanks,
> > > > > > > > > > > > Dhruvil
> > > > > > > > > > > >
> > > > > > > > > > > > On Mon, Sep 7, 2020 at 6:54 PM Harsha Ch <
> > > > harsha.ch@gmail.com>
> > > > > > > > > wrote:
> > > > > > > > > > > >
> > > > > > > > > > > > > Hi All,
> > > > > > > > > > > > >
> > > > > > > > > > > > > We are all working through the last meeting
> feedback.
> > > > I'll
> > > > > > cancel
> > > > > > > > > the
> > > > > > > > > > > > > tomorrow 's meeting and we can meanwhile continue
> our
> > > > > > discussion in
> > > > > > > > > > mailing
> > > > > > > > > > > > > list. We can start the regular meeting from next
> week
> > > > > > onwards.
> > > > > > > > > > > > >
> > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > >
> > > > > > > > > > > > > Harsha
> > > > > > > > > > > > >
> > > > > > > > > > > > > On Fri, Sep 04, 2020 at 8:41 AM, Satish Duggana <
> > > > > > > > > > satish.duggana@gmail.com
> > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Hi Jun,
> > > > > > > > > > > > > > Thanks for your thorough review and comments.
> > Please
> > > > find
> > > > > > the
> > > > > > > > > > inline
> > > > > > > > > > > > > > replies below.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 600. The topic deletion logic needs more details.
> > > > > > > > > > > > > > 600.1 The KIP mentions "The controller considers
> > the
> > > > topic
> > > > > > > > > > partition is
> > > > > > > > > > > > > > deleted only when it determines that there are no
> > log
> > > > > > segments
> > > > > > > > > for
> > > > > > > > > > that
> > > > > > > > > > > > > > topic partition by using RLMM". How is this done?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > It uses RLMM#listSegments() returns all the
> > segments
> > > > for
> > > > > > the
> > > > > > > > > given
> > > > > > > > > > topic
> > > > > > > > > > > > > > partition.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 600.2 "If the delete option is enabled then the
> > leader
> > > > > > will stop
> > > > > > > > > > RLM task
> > > > > > > > > > > > > > and stop processing and it sets all the remote
> log
> > > > segment
> > > > > > > > > > metadata of
> > > > > > > > > > > > > > that partition with a delete marker and publishes
> > them
> > > > to
> > > > > > RLMM."
> > > > > > > > > We
> > > > > > > > > > > > > > discussed this earlier. When a topic is being
> > deleted,
> > > > > > there may
> > > > > > > > > > not be a
> > > > > > > > > > > > > > leader for the deleted partition.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > This is a good point. As suggested in the
> meeting,
> > we
> > > > will
> > > > > > add a
> > > > > > > > > > separate
> > > > > > > > > > > > > > section for topic/partition deletion lifecycle
> and
> > this
> > > > > > scenario
> > > > > > > > > > will be
> > > > > > > > > > > > > > addressed.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 601. Unclean leader election
> > > > > > > > > > > > > > 601.1 Scenario 1: new empty follower
> > > > > > > > > > > > > > After step 1, the follower restores up to offset
> > 3. So
> > > > why
> > > > > > does
> > > > > > > > > it
> > > > > > > > > > have
> > > > > > > > > > > > > > LE-2 <https://issues.apache.org/jira/browse/LE-2
> >
> > at
> > > > > > offset 5?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Nice catch. It was showing the leader epoch
> fetched
> > > > from
> > > > > > the
> > > > > > > > > remote
> > > > > > > > > > > > > > storage. It should be shown with the truncated
> till
> > > > offset
> > > > > > 3.
> > > > > > > > > > Updated the
> > > > > > > > > > > > > > KIP.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 601.2 senario 5: After Step 3, leader A has
> > > > inconsistent
> > > > > > data
> > > > > > > > > > between its
> > > > > > > > > > > > > > local and the tiered data. For example. offset 3
> > has
> > > > msg 3
> > > > > > LE-0
> > > > > > > > > > <https://issues.apache.org/jira/browse/LE-0> locally,
> > > > > > > > > > > > > > but msg 5 LE-1 <
> > > > https://issues.apache.org/jira/browse/LE-1>
> > > > > > in
> > > > > > > > > > the remote store. While it's ok for the unclean leader
> > > > > > > > > > > > > > to lose data, it should still return consistent
> > data,
> > > > > > whether
> > > > > > > > > it's
> > > > > > > > > > from
> > > > > > > > > > > > > > the local or the remote store.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > There is no inconsistency here as LE-0
> > > > > > > > > > <https://issues.apache.org/jira/browse/LE-0> offsets are
> > [0,
> > > > 4]
> > > > > > and LE-2
> > > > > > > > > > <https://issues.apache.org/jira/browse/LE-2>:
> > > > > > > > > > > > > > [5, ]. It will always get the right records for
> the
> > > > given
> > > > > > offset
> > > > > > > > > > and
> > > > > > > > > > > > > > leader epoch. In case of remote, RSM is invoked
> to
> > get
> > > > the
> > > > > > remote
> > > > > > > > > > log
> > > > > > > > > > > > > > segment that contains the given offset with the
> > leader
> > > > > > epoch.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 601.4 It seems that retention is based on
> > > > > > > > > > > > > > listRemoteLogSegments(TopicPartition
> > topicPartition,
> > > > long
> > > > > > > > > > leaderEpoch).
> > > > > > > > > > > > > > When there is an unclean leader election, it's
> > possible
> > > > > > for the
> > > > > > > > > new
> > > > > > > > > > > > > leader
> > > > > > > > > > > > > > to not to include certain epochs in its epoch
> > cache.
> > > > How
> > > > > > are
> > > > > > > > > remote
> > > > > > > > > > > > > > segments associated with those epochs being
> > cleaned?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > That is a good point. This leader will also
> > cleanup the
> > > > > > epochs
> > > > > > > > > > earlier to
> > > > > > > > > > > > > > its start leader epoch and delete those segments.
> > It
> > > > gets
> > > > > > the
> > > > > > > > > > earliest
> > > > > > > > > > > > > > epoch for a partition and starts deleting
> segments
> > from
> > > > > > that
> > > > > > > > > leader
> > > > > > > > > > > > > epoch.
> > > > > > > > > > > > > > We need one more API in RLMM to get the earliest
> > leader
> > > > > > epoch.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 601.5 The KIP discusses the handling of unclean
> > leader
> > > > > > elections
> > > > > > > > > > for user
> > > > > > > > > > > > > > topics. What about unclean leader elections on
> > > > > > > > > > > > > > __remote_log_segment_metadata?
> > > > > > > > > > > > > > This is the same as other system topics like
> > > > > > consumer_offsets,
> > > > > > > > > > > > > > __transaction_state topics. As discussed in the
> > > > meeting,
> > > > > > we will
> > > > > > > > > > add the
> > > > > > > > > > > > > > behavior of __remote_log_segment_metadata topic’s
> > > > unclean
> > > > > > leader
> > > > > > > > > > > > > > truncation.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 602. It would be useful to clarify the
> limitations
> > in
> > > > the
> > > > > > initial
> > > > > > > > > > > > > release.
> > > > > > > > > > > > > > The KIP mentions not supporting compacted topics.
> > What
> > > > > > about JBOD
> > > > > > > > > > and
> > > > > > > > > > > > > > changing the configuration of a topic from delete
> > to
> > > > > > compact
> > > > > > > > > after
> > > > > > > > > > > > > remote.
> > > > > > > > > > > > > > log. storage. enable (
> > > > http://remote.log.storage.enable/
> > > > > > ) is
> > > > > > > > > > enabled?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > This was updated in the KIP earlier.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 603. RLM leader tasks:
> > > > > > > > > > > > > > 603.1"It checks for rolled over LogSegments
> (which
> > have
> > > > > > the last
> > > > > > > > > > message
> > > > > > > > > > > > > > offset less than last stable offset of that topic
> > > > > > partition) and
> > > > > > > > > > copies
> > > > > > > > > > > > > > them along with their offset/time/transaction
> > indexes
> > > > and
> > > > > > leader
> > > > > > > > > > epoch
> > > > > > > > > > > > > > cache to the remote tier." It needs to copy the
> > > > producer
> > > > > > snapshot
> > > > > > > > > > too.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Right. It copies producer snapshots too as
> > mentioned in
> > > > > > > > > > LogSegmentData.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 603.2 "Local logs are not cleaned up till those
> > > > segments
> > > > > > are
> > > > > > > > > copied
> > > > > > > > > > > > > > successfully to remote even though their
> retention
> > > > > > time/size is
> > > > > > > > > > reached"
> > > > > > > > > > > > > > This seems weird. If the tiering stops because
> the
> > > > remote
> > > > > > store
> > > > > > > > > is
> > > > > > > > > > not
> > > > > > > > > > > > > > available, we don't want the local data to grow
> > > > forever.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > It was clarified in the discussion that the
> > comment was
> > > > > > more
> > > > > > > > > about
> > > > > > > > > > the
> > > > > > > > > > > > > > local storage goes beyond the log.retention. The
> > above
> > > > > > statement
> > > > > > > > > > is about
> > > > > > > > > > > > > > local.log.retention but not for the complete
> > > > > > log.retention. When
> > > > > > > > > it
> > > > > > > > > > > > > > reaches the log.retention then it will delete the
> > local
> > > > > > logs even
> > > > > > > > > > though
> > > > > > > > > > > > > > those are not copied to remote storage.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 604. "RLM maintains a bounded cache(possibly LRU)
> > of
> > > > the
> > > > > > index
> > > > > > > > > > files of
> > > > > > > > > > > > > > remote log segments to avoid multiple index
> fetches
> > > > from
> > > > > > the
> > > > > > > > > remote
> > > > > > > > > > > > > > storage. These indexes can be used in the same
> way
> > as
> > > > local
> > > > > > > > > segment
> > > > > > > > > > > > > > indexes are used." Could you provide more details
> > on
> > > > this?
> > > > > > Are
> > > > > > > > > the
> > > > > > > > > > > > > indexes
> > > > > > > > > > > > > > cached in memory or on disk? If on disk, where
> are
> > they
> > > > > > stored?
> > > > > > > > > > Are the
> > > > > > > > > > > > > > cached indexes bound by a certain size?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > These are cached on disk and stored in log.dir
> > with a
> > > > name
> > > > > > > > > > > > > > “__remote_log_index_cache”. They are bound by the
> > total
> > > > > > size.
> > > > > > > > > This
> > > > > > > > > > will
> > > > > > > > > > > > > be
> > > > > > > > > > > > > > exposed as a user configuration,
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 605. BuildingRemoteLogAux
> > > > > > > > > > > > > > 605.1 In this section, two options are listed.
> > Which
> > > > one is
> > > > > > > > > chosen?
> > > > > > > > > > > > > > Option-2, updated the KIP.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 605.2 In option 2, it says "Build the local
> leader
> > > > epoch
> > > > > > cache by
> > > > > > > > > > cutting
> > > > > > > > > > > > > > the leader epoch sequence received from remote
> > storage
> > > > to
> > > > > > [LSO,
> > > > > > > > > > ELO].
> > > > > > > > > > > > > (LSO
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > = log start offset)." We need to do the same
> thing
> > for
> > > > the
> > > > > > > > > producer
> > > > > > > > > > > > > > snapshot. However, it's hard to cut the producer
> > > > snapshot
> > > > > > to an
> > > > > > > > > > earlier
> > > > > > > > > > > > > > offset. Another option is to simply take the
> > lastOffset
> > > > > > from the
> > > > > > > > > > remote
> > > > > > > > > > > > > > segment and use that as the starting fetch offset
> > in
> > > > the
> > > > > > > > > follower.
> > > > > > > > > > This
> > > > > > > > > > > > > > avoids the need for cutting.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Right, this was mentioned in the “transactional
> > > > support”
> > > > > > section
> > > > > > > > > > about
> > > > > > > > > > > > > > adding these details.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 606. ListOffsets: Since we need a version bump,
> > could
> > > > you
> > > > > > > > > document
> > > > > > > > > > it
> > > > > > > > > > > > > > under a protocol change section?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Sure, we will update the KIP.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 607. "LogStartOffset of a topic can point to
> > either of
> > > > > > local
> > > > > > > > > > segment or
> > > > > > > > > > > > > > remote segment but it is initialised and
> > maintained in
> > > > the
> > > > > > Log
> > > > > > > > > > class like
> > > > > > > > > > > > > > now. This is already maintained in `Log` class
> > while
> > > > > > loading the
> > > > > > > > > > logs and
> > > > > > > > > > > > > > it can also be fetched from
> > RemoteLogMetadataManager."
> > > > > > What will
> > > > > > > > > > happen
> > > > > > > > > > > > > to
> > > > > > > > > > > > > > the existing logic (e.g. log recovery) that
> > currently
> > > > > > depends on
> > > > > > > > > > > > > > logStartOffset but assumes it's local?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > They use a field called localLogStartOffset which
> > is
> > > > the
> > > > > > local
> > > > > > > > > log
> > > > > > > > > > start
> > > > > > > > > > > > > > offset..
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 608. Handle expired remote segment: How does it
> > pick
> > > > up new
> > > > > > > > > > > > > logStartOffset
> > > > > > > > > > > > > > from deleteRecords?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Good point. This was not addressed in the KIP.
> Will
> > > > update
> > > > > > the
> > > > > > > > > KIP
> > > > > > > > > > on how
> > > > > > > > > > > > > > the RLM task handles this scenario.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 609. RLMM message format:
> > > > > > > > > > > > > > 609.1 It includes both MaxTimestamp and
> > EventTimestamp.
> > > > > > Where
> > > > > > > > > does
> > > > > > > > > > it get
> > > > > > > > > > > > > > both since the message in the log only contains
> one
> > > > > > timestamp?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > `EventTimeStamp` is the timestamp at which that
> > segment
> > > > > > metadata
> > > > > > > > > > event is
> > > > > > > > > > > > > > generated. This is more for audits.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 609.2 If we change just the state (e.g. to
> > > > > > DELETE_STARTED), it
> > > > > > > > > > seems it's
> > > > > > > > > > > > > > wasteful to have to include all other fields not
> > > > changed.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > This is a good point. We thought about
> incremental
> > > > > > updates. But
> > > > > > > > > we
> > > > > > > > > > want
> > > > > > > > > > > > > to
> > > > > > > > > > > > > > make sure all the events are in the expected
> order
> > and
> > > > take
> > > > > > > > > action
> > > > > > > > > > based
> > > > > > > > > > > > > > on the latest event. Will think through the
> > approaches
> > > > in
> > > > > > detail
> > > > > > > > > > and
> > > > > > > > > > > > > > update here.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 609.3 Could you document which process makes the
> > > > following
> > > > > > > > > > transitions
> > > > > > > > > > > > > > DELETE_MARKED, DELETE_STARTED, DELETE_FINISHED?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Okay, will document more details.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 610. remote.log.reader.max.pending.tasks:
> "Maximum
> > > > remote
> > > > > > log
> > > > > > > > > > reader
> > > > > > > > > > > > > > thread pool task queue size. If the task queue is
> > full,
> > > > > > broker
> > > > > > > > > > will stop
> > > > > > > > > > > > > > reading remote log segments." What does the
> broker
> > do
> > > > if
> > > > > > the
> > > > > > > > > queue
> > > > > > > > > > is
> > > > > > > > > > > > > > full?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > It returns an error for this topic partition.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 611. What do we return if the request
> offset/epoch
> > > > doesn't
> > > > > > exist
> > > > > > > > > > in the
> > > > > > > > > > > > > > following API?
> > > > > > > > > > > > > > RemoteLogSegmentMetadata
> > > > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > > > > > > topicPartition, long offset, int epochForOffset)
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > This returns null. But we prefer to update the
> > return
> > > > type
> > > > > > as
> > > > > > > > > > Optional
> > > > > > > > > > > > > and
> > > > > > > > > > > > > > return Empty if that does not exist.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > Satish.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > On Tue, Sep 1, 2020 at 9:45 AM Jun Rao < jun@
> > > > confluent.
> > > > > > io (
> > > > > > > > > > > > > > jun@confluent.io ) > wrote:
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >> Hi, Satish,
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >> Thanks for the updated KIP. Made another pass. A
> > few
> > > > more
> > > > > > > > > comments
> > > > > > > > > > > > > below.
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >> 600. The topic deletion logic needs more
> details.
> > > > > > > > > > > > > >> 600.1 The KIP mentions "The controller considers
> > the
> > > > topic
> > > > > > > > > > partition is
> > > > > > > > > > > > > >> deleted only when it determines that there are
> no
> > log
> > > > > > segments
> > > > > > > > > > for that
> > > > > > > > > > > > > >> topic partition by using RLMM". How is this
> done?
> > > > 600.2
> > > > > > "If the
> > > > > > > > > > delete
> > > > > > > > > > > > > >> option is enabled then the leader will stop RLM
> > task
> > > > and
> > > > > > stop
> > > > > > > > > > processing
> > > > > > > > > > > > > >> and it sets all the remote log segment metadata
> of
> > > > that
> > > > > > > > > partition
> > > > > > > > > > with a
> > > > > > > > > > > > > >> delete marker and publishes them to RLMM." We
> > > > discussed
> > > > > > this
> > > > > > > > > > earlier.
> > > > > > > > > > > > > When
> > > > > > > > > > > > > >> a topic is being deleted, there may not be a
> > leader
> > > > for
> > > > > > the
> > > > > > > > > > deleted
> > > > > > > > > > > > > >> partition.
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >> 601. Unclean leader election
> > > > > > > > > > > > > >> 601.1 Scenario 1: new empty follower
> > > > > > > > > > > > > >> After step 1, the follower restores up to offset
> > 3. So
> > > > > > why does
> > > > > > > > > > it have
> > > > > > > > > > > > > >> LE-2 <
> https://issues.apache.org/jira/browse/LE-2>
> > at
> > > > > > offset 5?
> > > > > > > > > > > > > >> 601.2 senario 5: After Step 3, leader A has
> > > > inconsistent
> > > > > > data
> > > > > > > > > > between
> > > > > > > > > > > > > its
> > > > > > > > > > > > > >> local and the tiered data. For example. offset 3
> > has
> > > > msg
> > > > > > 3 LE-0
> > > > > > > > > > <https://issues.apache.org/jira/browse/LE-0> locally,
> > > > > > > > > > > > > >> but msg 5 LE-1 <
> > > > > > https://issues.apache.org/jira/browse/LE-1> in
> > > > > > > > > > the remote store. While it's ok for the unclean leader
> > > > > > > > > > > > > >> to lose data, it should still return consistent
> > data,
> > > > > > whether
> > > > > > > > > > it's from
> > > > > > > > > > > > > >> the local or the remote store.
> > > > > > > > > > > > > >> 601.3 The follower picks up log start offset
> > using the
> > > > > > following
> > > > > > > > > > api.
> > > > > > > > > > > > > >> Suppose that we have 3 remote segments (LE,
> > > > > > SegmentStartOffset)
> > > > > > > > > > as (2,
> > > > > > > > > > > > > >> 10),
> > > > > > > > > > > > > >> (3, 20) and (7, 15) due to an unclean leader
> > election.
> > > > > > Using the
> > > > > > > > > > > > > following
> > > > > > > > > > > > > >> api will cause logStartOffset to go backward
> from
> > 20
> > > > to
> > > > > > 15. How
> > > > > > > > > > do we
> > > > > > > > > > > > > >> prevent that?
> > > > > > > > > > > > > >> earliestLogOffset(TopicPartition topicPartition,
> > int
> > > > > > > > > leaderEpoch)
> > > > > > > > > > 601.4
> > > > > > > > > > > > > It
> > > > > > > > > > > > > >> seems that retention is based on
> > > > > > > > > > > > > >> listRemoteLogSegments(TopicPartition
> > topicPartition,
> > > > long
> > > > > > > > > > leaderEpoch).
> > > > > > > > > > > > > >> When there is an unclean leader election, it's
> > > > possible
> > > > > > for the
> > > > > > > > > > new
> > > > > > > > > > > > > leader
> > > > > > > > > > > > > >> to not to include certain epochs in its epoch
> > cache.
> > > > How
> > > > > > are
> > > > > > > > > > remote
> > > > > > > > > > > > > >> segments associated with those epochs being
> > cleaned?
> > > > > > 601.5 The
> > > > > > > > > KIP
> > > > > > > > > > > > > >> discusses the handling of unclean leader
> > elections for
> > > > > > user
> > > > > > > > > > topics. What
> > > > > > > > > > > > > >> about unclean leader elections on
> > > > > > > > > > > > > >> __remote_log_segment_metadata?
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >> 602. It would be useful to clarify the
> > limitations in
> > > > the
> > > > > > > > > initial
> > > > > > > > > > > > > release.
> > > > > > > > > > > > > >> The KIP mentions not supporting compacted
> topics.
> > What
> > > > > > about
> > > > > > > > > JBOD
> > > > > > > > > > and
> > > > > > > > > > > > > >> changing the configuration of a topic from
> delete
> > to
> > > > > > compact
> > > > > > > > > after
> > > > > > > > > > > > > remote.
> > > > > > > > > > > > > >> log. storage. enable (
> > > > http://remote.log.storage.enable/
> > > > > > ) is
> > > > > > > > > > enabled?
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >> 603. RLM leader tasks:
> > > > > > > > > > > > > >> 603.1"It checks for rolled over LogSegments
> (which
> > > > have
> > > > > > the last
> > > > > > > > > > message
> > > > > > > > > > > > > >> offset less than last stable offset of that
> topic
> > > > > > partition) and
> > > > > > > > > > copies
> > > > > > > > > > > > > >> them along with their offset/time/transaction
> > indexes
> > > > and
> > > > > > leader
> > > > > > > > > > epoch
> > > > > > > > > > > > > >> cache to the remote tier." It needs to copy the
> > > > producer
> > > > > > > > > snapshot
> > > > > > > > > > too.
> > > > > > > > > > > > > >> 603.2 "Local logs are not cleaned up till those
> > > > segments
> > > > > > are
> > > > > > > > > > copied
> > > > > > > > > > > > > >> successfully to remote even though their
> retention
> > > > > > time/size is
> > > > > > > > > > reached"
> > > > > > > > > > > > > >> This seems weird. If the tiering stops because
> the
> > > > remote
> > > > > > store
> > > > > > > > > > is not
> > > > > > > > > > > > > >> available, we don't want the local data to grow
> > > > forever.
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >> 604. "RLM maintains a bounded cache(possibly
> LRU)
> > of
> > > > the
> > > > > > index
> > > > > > > > > > files of
> > > > > > > > > > > > > >> remote log segments to avoid multiple index
> > fetches
> > > > from
> > > > > > the
> > > > > > > > > > remote
> > > > > > > > > > > > > >> storage. These indexes can be used in the same
> > way as
> > > > > > local
> > > > > > > > > > segment
> > > > > > > > > > > > > >> indexes are used." Could you provide more
> details
> > on
> > > > > > this? Are
> > > > > > > > > the
> > > > > > > > > > > > > indexes
> > > > > > > > > > > > > >> cached in memory or on disk? If on disk, where
> are
> > > > they
> > > > > > stored?
> > > > > > > > > > Are the
> > > > > > > > > > > > > >> cached indexes bound by a certain size?
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >> 605. BuildingRemoteLogAux
> > > > > > > > > > > > > >> 605.1 In this section, two options are listed.
> > Which
> > > > one
> > > > > > is
> > > > > > > > > > chosen?
> > > > > > > > > > > > > 605.2
> > > > > > > > > > > > > >> In option 2, it says "Build the local leader
> epoch
> > > > cache
> > > > > > by
> > > > > > > > > > cutting the
> > > > > > > > > > > > > >> leader epoch sequence received from remote
> > storage to
> > > > > > [LSO,
> > > > > > > > > ELO].
> > > > > > > > > > (LSO
> > > > > > > > > > > > > >> = log start offset)." We need to do the same
> thing
> > > > for the
> > > > > > > > > > producer
> > > > > > > > > > > > > >> snapshot. However, it's hard to cut the producer
> > > > snapshot
> > > > > > to an
> > > > > > > > > > earlier
> > > > > > > > > > > > > >> offset. Another option is to simply take the
> > > > lastOffset
> > > > > > from the
> > > > > > > > > > remote
> > > > > > > > > > > > > >> segment and use that as the starting fetch
> offset
> > in
> > > > the
> > > > > > > > > > follower. This
> > > > > > > > > > > > > >> avoids the need for cutting.
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >> 606. ListOffsets: Since we need a version bump,
> > could
> > > > you
> > > > > > > > > > document it
> > > > > > > > > > > > > >> under a protocol change section?
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >> 607. "LogStartOffset of a topic can point to
> > either of
> > > > > > local
> > > > > > > > > > segment or
> > > > > > > > > > > > > >> remote segment but it is initialised and
> > maintained in
> > > > > > the Log
> > > > > > > > > > class
> > > > > > > > > > > > > like
> > > > > > > > > > > > > >> now. This is already maintained in `Log` class
> > while
> > > > > > loading the
> > > > > > > > > > logs
> > > > > > > > > > > > > and
> > > > > > > > > > > > > >> it can also be fetched from
> > RemoteLogMetadataManager."
> > > > > > What will
> > > > > > > > > > happen
> > > > > > > > > > > > > to
> > > > > > > > > > > > > >> the existing logic (e.g. log recovery) that
> > currently
> > > > > > depends on
> > > > > > > > > > > > > >> logStartOffset but assumes it's local?
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >> 608. Handle expired remote segment: How does it
> > pick
> > > > up
> > > > > > new
> > > > > > > > > > > > > logStartOffset
> > > > > > > > > > > > > >> from deleteRecords?
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >> 609. RLMM message format:
> > > > > > > > > > > > > >> 609.1 It includes both MaxTimestamp and
> > > > EventTimestamp.
> > > > > > Where
> > > > > > > > > > does it
> > > > > > > > > > > > > get
> > > > > > > > > > > > > >> both since the message in the log only contains
> > one
> > > > > > timestamp?
> > > > > > > > > > 609.2 If
> > > > > > > > > > > > > we
> > > > > > > > > > > > > >> change just the state (e.g. to DELETE_STARTED),
> it
> > > > seems
> > > > > > it's
> > > > > > > > > > wasteful
> > > > > > > > > > > > > to
> > > > > > > > > > > > > >> have to include all other fields not changed.
> > 609.3
> > > > Could
> > > > > > you
> > > > > > > > > > document
> > > > > > > > > > > > > >> which process makes the following transitions
> > > > > > DELETE_MARKED,
> > > > > > > > > > > > > >> DELETE_STARTED, DELETE_FINISHED?
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >> 610. remote.log.reader.max.pending.tasks:
> "Maximum
> > > > remote
> > > > > > log
> > > > > > > > > > reader
> > > > > > > > > > > > > >> thread pool task queue size. If the task queue
> is
> > > > full,
> > > > > > broker
> > > > > > > > > > will stop
> > > > > > > > > > > > > >> reading remote log segments." What does the
> > broker do
> > > > if
> > > > > > the
> > > > > > > > > > queue is
> > > > > > > > > > > > > >> full?
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >> 611. What do we return if the request
> offset/epoch
> > > > > > doesn't exist
> > > > > > > > > > in the
> > > > > > > > > > > > > >> following API?
> > > > > > > > > > > > > >> RemoteLogSegmentMetadata
> > > > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > > > > > >> topicPartition, long offset, int epochForOffset)
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >> Jun
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >> On Mon, Aug 31, 2020 at 11:19 AM Satish Duggana
> <
> > > > satish.
> > > > > > > > > duggana@
> > > > > > > > > > > > > gmail. com
> > > > > > > > > > > > > >> ( satish.duggana@gmail.com ) > wrote:
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>> KIP is updated with
> > > > > > > > > > > > > >>> - Remote log segment metadata topic message
> > > > > > format/schema.
> > > > > > > > > > > > > >>> - Added remote log segment metadata state
> > > > transitions and
> > > > > > > > > > explained how
> > > > > > > > > > > > > >>> the deletion of segments is handled, including
> > the
> > > > case
> > > > > > of
> > > > > > > > > > partition
> > > > > > > > > > > > > >>> deletions.
> > > > > > > > > > > > > >>> - Added a few more limitations in the "Non
> goals"
> > > > > > section.
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>> Thanks,
> > > > > > > > > > > > > >>> Satish.
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>> On Thu, Aug 27, 2020 at 12:42 AM Harsha Ch <
> > harsha.
> > > > ch@
> > > > > > > > > gmail.
> > > > > > > > > > com (
> > > > > > > > > > > > > >>> harsha.ch@gmail.com ) > wrote:
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>> Updated the KIP with Meeting Notes section
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>> https:/ / cwiki. apache. org/ confluence/
> > display/
> > > > KAFKA/
> > > > > > > > > > > > > KIP-405 <
> > https://issues.apache.org/jira/browse/KIP-405>
> > > > > > > > > >
> > %3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> > > > > > > > > > > > > >>> (
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > >
> > > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-405%3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> > > > > > > > > > > > > >>> )
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>> On Tue, Aug 25, 2020 at 1:03 PM Jun Rao < jun@
> > > > > > confluent. io
> > > > > > > > > (
> > > > > > > > > > > > > >>>> jun@confluent.io ) > wrote:
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>> Hi, Harsha,
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>> Thanks for the summary. Could you add the
> > summary
> > > > and
> > > > > > the
> > > > > > > > > > recording
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>> link to
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>> the last section of
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>> https:/ / cwiki. apache. org/ confluence/
> > display/
> > > > KAFKA/
> > > > > > > > > > > > > Kafka+Improvement+Proposals
> > > > > > > > > > > > > >>> (
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > >
> > > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/Kafka+Improvement+Proposals
> > > > > > > > > > > > > >>> )
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>> ?
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>> Jun
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>> On Tue, Aug 25, 2020 at 11:12 AM Harsha
> > > > Chintalapani <
> > > > > > kafka@
> > > > > > > > > > > > > harsha. io (
> > > > > > > > > > > > > >>>>> kafka@harsha.io ) > wrote:
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>> Thanks everyone for attending the meeting
> > today.
> > > > > > > > > > > > > >>>>>> Here is the recording
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>> https:/ / drive. google. com/ file/ d/
> > > > > > > > > > > > > 14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/ view?usp=sharing
> > > > > > > > > > > > > >>> (
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > >
> > > >
> >
> https://drive.google.com/file/d/14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/view?usp=sharing
> > > > > > > > > > > > > >>> )
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>> Notes:
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>> 1. KIP is updated with follower fetch
> > protocol and
> > > > > > ready to
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>> reviewed
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>> 2. Satish to capture schema of internal
> > metadata
> > > > > > topic in
> > > > > > > > > the
> > > > > > > > > > KIP
> > > > > > > > > > > > > >>>>>> 3. We will update the KIP with details of
> > > > different
> > > > > > cases
> > > > > > > > > > > > > >>>>>> 4. Test plan will be captured in a doc and
> > will
> > > > add
> > > > > > to the
> > > > > > > > > KIP
> > > > > > > > > > > > > >>>>>> 5. Add a section "Limitations" to capture
> the
> > > > > > capabilities
> > > > > > > > > > that
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>> will
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>> be
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>> introduced with this KIP and what will not
> be
> > > > covered
> > > > > > in
> > > > > > > > > this
> > > > > > > > > > KIP.
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>> Please add to it I missed anything. Will
> > produce a
> > > > > > formal
> > > > > > > > > > meeting
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>> notes
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>> from next meeting onwards.
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>> Thanks,
> > > > > > > > > > > > > >>>>>> Harsha
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>> On Mon, Aug 24, 2020 at 9:42 PM, Ying Zheng
> <
> > > > yingz@
> > > > > > uber.
> > > > > > > > > > com.
> > > > > > > > > > > > > invalid (
> > > > > > > > > > > > > >>>>>> yingz@uber.com.invalid ) > wrote:
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> We did some basic feature tests at Uber.
> The
> > test
> > > > > > cases and
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>> results are
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> shared in this google doc:
> > > > > > > > > > > > > >>>>>>> https:/ / docs. google. com/ spreadsheets/
> > d/ (
> > > > > > > > > > > > > >>>>>>> https://docs.google.com/spreadsheets/d/ )
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > >
> 1XhNJqjzwXvMCcAOhEH0sSXU6RTvyoSf93DHF-YMfGLk/edit?usp=sharing
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> The performance test results were already
> > shared
> > > > in
> > > > > > the KIP
> > > > > > > > > > last
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>> month.
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> On Mon, Aug 24, 2020 at 11:10 AM Harsha Ch
> <
> > > > harsha.
> > > > > > ch@
> > > > > > > > > > gmail.
> > > > > > > > > > > > > com (
> > > > > > > > > > > > > >>>>>>> harsha.ch@gmail.com ) >
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>> wrote:
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> "Understand commitments towards driving
> > design &
> > > > > > > > > > implementation of
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>> the
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>> KIP
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> further and how it aligns with participant
> > > > interests
> > > > > > in
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>> contributing to
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>> the
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> efforts (ex: in the context of Uber’s Q3/Q4
> > > > > > roadmap)." What
> > > > > > > > > > is that
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>> about?
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> On Mon, Aug 24, 2020 at 11:05 AM Kowshik
> > > > Prakasam <
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>> kprakasam@ confluent. io (
> > kprakasam@confluent.io
> > > > ) >
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> wrote:
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> Hi Harsha,
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> The following google doc contains a
> proposal
> > for
> > > > > > temporary
> > > > > > > > > > agenda
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>> for
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>> the
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> KIP-405 <
> > > > > > https://issues.apache.org/jira/browse/KIP-405> <
> > > > > > > > > > https:/ / issues. apache. org/ jira/ browse/ KIP-405
> > > > > > > > > > <https://issues.apache.org/jira/browse/KIP-405> (
> > > > > > > > > > > > > >>>>>>>
> > https://issues.apache.org/jira/browse/KIP-405 )
> > > > >
> > > > > > sync
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>> meeting
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> tomorrow:
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> https:/ / docs. google. com/ document/ d/ (
> > > > > > > > > > > > > >>>>>>> https://docs.google.com/document/d/ )
> > > > > > > > > > > > > >>>>>>>
> > 1pqo8X5LU8TpwfC_iqSuVPezhfCfhGkbGN2TqiPA3LBU/edit
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> .
> > > > > > > > > > > > > >>>>>>> Please could you add it to the Google
> > calendar
> > > > > > invite?
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> Thank you.
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> Cheers,
> > > > > > > > > > > > > >>>>>>> Kowshik
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> On Thu, Aug 20, 2020 at 10:58 AM Harsha Ch
> <
> > > > harsha.
> > > > > > ch@
> > > > > > > > > > gmail.
> > > > > > > > > > > > > com (
> > > > > > > > > > > > > >>>>>>> harsha.ch@gmail.com ) >
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>> wrote:
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> Hi All,
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> Scheduled a meeting for Tuesday 9am - 10am.
> > I can
> > > > > > record
> > > > > > > > > and
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>> upload for
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> community to be able to follow the
> > discussion.
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> Jun, please add the required folks on
> > confluent
> > > > side.
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> Thanks,
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> Harsha
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> On Thu, Aug 20, 2020 at 12:33 AM, Alexandre
> > > > Dupriez <
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>> alexandre.dupriez@
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> gmail. com ( http://gmail.com/ ) > wrote:
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> Hi Jun,
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> Many thanks for your initiative.
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> If you like, I am happy to attend at the
> > time you
> > > > > > > > > suggested.
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> Many thanks,
> > > > > > > > > > > > > >>>>>>> Alexandre
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> Le mer. 19 août 2020 à 22:00, Harsha Ch <
> > > > harsha. ch@
> > > > > > > > > > gmail. com (
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>> harsha.
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> ch@ gmail. com ( ch@gmail.com ) ) > a
> écrit
> > :
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> Hi Jun,
> > > > > > > > > > > > > >>>>>>> Thanks. This will help a lot. Tuesday will
> > work
> > > > for
> > > > > > us.
> > > > > > > > > > > > > >>>>>>> -Harsha
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> On Wed, Aug 19, 2020 at 1:24 PM Jun Rao <
> > jun@
> > > > > > confluent.
> > > > > > > > > > io (
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>> jun@
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> confluent. io ( http://confluent.io/ ) ) >
> > > > wrote:
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> Hi, Satish, Ying, Harsha,
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> Do you think it would be useful to have a
> > regular
> > > > > > virtual
> > > > > > > > > > meeting
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>> to
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> discuss this KIP? The goal of the meeting
> > will be
> > > > > > sharing
> > > > > > > > > > > > > >>>>>>> design/development progress and discussing
> > any
> > > > open
> > > > > > issues
> > > > > > > > > to
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> accelerate
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> this KIP. If so, will every Tuesday (from
> > next
> > > > week)
> > > > > > > > > 9am-10am
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> PT
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> work for you? I can help set up a Zoom
> > meeting,
> > > > > > invite
> > > > > > > > > > everyone who
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> might
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> be interested, have it recorded and shared,
> > etc.
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> Thanks,
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> Jun
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> On Tue, Aug 18, 2020 at 11:01 AM Satish
> > Duggana <
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> satish. duggana@ gmail. com ( satish.
> > duggana@
> > > > > > gmail. com
> > > > > > > > > (
> > > > > > > > > > > > > >>>>>>> satish.duggana@gmail.com ) ) >
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> wrote:
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> Hi Kowshik,
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> Thanks for looking into the KIP and sending
> > your
> > > > > > comments.
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> 5001. Under the section "Follower fetch
> > protocol
> > > > in
> > > > > > > > > detail",
> > > > > > > > > > the
> > > > > > > > > > > > > >>>>>>> next-local-offset is the offset upto which
> > the
> > > > > > segments are
> > > > > > > > > > copied
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > >
> > > > > >
> > > > > >
> > > >
> >
>

Re: [DISCUSS] KIP-405: Kafka Tiered Storage

[Satish Duggana <sa...@gmail.com>]

Hi Kowshik,
Thanks for your comments. Please find the inline replies below.

9002. Under the "Upgrade" section, the configuration mentioned is
'remote.log.storage.system.enable'. However, under "Public Interfaces"
section the corresponding configuration is 'remote.storage.system.enable'.
Could we use the same one in both, maybe 'remote.log.storage.system.enable'?

Nice catch, updated the KIP.

9003. Under "Per Topic Configuration", the KIP recommends setting
'remote.log.storage.enable' to true at a per-topic level. It will be useful
to add a line that if the user wants to enable it for all topics, then they
should be able to set the cluster-wide default to true. Also, it will be
useful to mention that the KIP currently does not support setting it to
false (after it is set to true), and add that to the future work section.

We do not want to expose a config at cluster level in the initial
version. We will add that in the future. Both limitations are added to
future work.


9004. Under "Committed offsets file format", the sample provided shows
partition number and offset. Is the topic name required for identifying
which topic the partitions belong to?
File name is already mentioned as _rlmm_committed_offsets‘’ and we
already know the internal remote log metadata topic name and it is
never going to be changed.

9005. Under "Internal flat-file store format of remote log metadata", it
seems useful to specify both topic name and topic ID for debugging
purposes.

That makes sense, updated.

9006. Under "Internal flat-file store format of remote log metadata", the
description of "metadata-topic-offset" currently says "offset of the remote
log metadata topic from which this topic partition's remote log metadata is
fetched." Just for the wording, perhaps you meant to refer to the offset
upto which the file has been committed? i.e. "offset of the remote log
metadata topic upto which this topic partition's remote log metadata has
been committed into this file."
Updated

9007. Under "Internal flat-file store format of remote log metadata", the
schema of the payload (i.e. beyond the header) seems to contain the events
from the metadata topic. It seems useful to instead persist the
representation of the materialized state of the events, so that for the
same segment only the latest state is stored. Besides reducing storage
footprint, this also is likely to relate directly with the in-memory
representation of the RLMM cache (which probably is some kind of a Map with
key being segment ID and value being the segment state), so recovery from
disk will be straightforward.

This is what we already do and clarified  in the earlier meeting..

9008. Under "Topic deletion lifecycle", step (1), it will be useful to
mention when in the deletion flow does the controller publish the
delete_partition_marked event to say that the partition is marked for
deletion?
Updated.

9009. There are ~4 TODOs in the KIP. Could you please address these or
remove them?
Updated.

9010. There is a reference to a Google doc on the KIP which was used
earlier for discussions. Please could you remove the reference, since the
KIP is the source of the truth?

Which doc reference are you saying?

9011. This feedback is from an earlier comment. In the RemoteStorageManager
interface, there is an API defined for each file type. For example,
fetchOffsetIndex, fetchTimestampIndex etc. To avoid the duplication, I'd
suggest we can instead have a FileType enum and a common get API based on
the FileType. What do you think?

Sure, updated in the KIP.



On Tue, 15 Dec 2020 at 22:17, Kowshik Prakasam <kp...@confluent.io> wrote:
>
> Hi Satish,
>
> Thanks for the updates! A few more comments below.
>
> 9001. Under the "Upgrade" section, there is a line mentioning: "Upgrade the
> existing Kafka cluster to 2.7 version and allow this to run for the log
> retention of user topics that you want to enable tiered storage. This will
> allow all the topics to have the producer snapshots generated for each log
> segment." -- Which associated change in AK were you referring to here? Is
> it: https://github.com/apache/kafka/pull/7929 ? It seems like I don't see
> it in the 2.7 release branch yet, here is the link:
> https://github.com/apache/kafka/commits/2.7.
>
> 9002. Under the "Upgrade" section, the configuration mentioned is
> 'remote.log.storage.system.enable'. However, under "Public Interfaces"
> section the corresponding configuration is 'remote.storage.system.enable'.
> Could we use the same one in both, maybe 'remote.log.storage.system.enable'?
>
> 9003. Under "Per Topic Configuration", the KIP recommends setting
> 'remote.log.storage.enable' to true at a per-topic level. It will be useful
> to add a line that if the user wants to enable it for all topics, then they
> should be able to set the cluster-wide default to true. Also, it will be
> useful to mention that the KIP currently does not support setting it to
> false (after it is set to true), and add that to the future work section.
>
> 9004. Under "Committed offsets file format", the sample provided shows
> partition number and offset. Is the topic name required for identifying
> which topic the partitions belong to?
>
> 9005. Under "Internal flat-file store format of remote log metadata", it
> seems useful to specify both topic name and topic ID for debugging
> purposes.
>
> 9006. Under "Internal flat-file store format of remote log metadata", the
> description of "metadata-topic-offset" currently says "offset of the remote
> log metadata topic from which this topic partition's remote log metadata is
> fetched." Just for the wording, perhaps you meant to refer to the offset
> upto which the file has been committed? i.e. "offset of the remote log
> metadata topic upto which this topic partition's remote log metadata has
> been committed into this file."
>
> 9007. Under "Internal flat-file store format of remote log metadata", the
> schema of the payload (i.e. beyond the header) seems to contain the events
> from the metadata topic. It seems useful to instead persist the
> representation of the materialized state of the events, so that for the
> same segment only the latest state is stored. Besides reducing storage
> footprint, this also is likely to relate directly with the in-memory
> representation of the RLMM cache (which probably is some kind of a Map with
> key being segment ID and value being the segment state), so recovery from
> disk will be straightforward.
>
> 9008. Under "Topic deletion lifecycle", step (1), it will be useful to
> mention when in the deletion flow does the controller publish the
> delete_partition_marked event to say that the partition is marked for
> deletion?
>
> 9009. There are ~4 TODOs in the KIP. Could you please address these or
> remove them?
>
> 9010. There is a reference to a Google doc on the KIP which was used
> earlier for discussions. Please could you remove the reference, since the
> KIP is the source of the truth?
>
> 9011. This feedback is from an earlier comment. In the RemoteStorageManager
> interface, there is an API defined for each file type. For example,
> fetchOffsetIndex, fetchTimestampIndex etc. To avoid the duplication, I'd
> suggest we can instead have a FileType enum and a common get API based on
> the FileType. What do you think?
>
>
> Cheers,
> Kowshik
>
>
> On Mon, Dec 14, 2020 at 11:07 AM Satish Duggana <sa...@gmail.com>
> wrote:
>
> > Hi Jun,
> > Thanks for your comments. Please go through the inline replies.
> >
> >
> > 5102.2: It seems that both positions can just be int. Another option is to
> > have two methods. Would it be clearer?
> >
> >     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> > remoteLogSegmentMetadata,  int startPosition) throwsRemoteStorageException;
> >
> >     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> > remoteLogSegmentMetadata, int startPosition, int endPosition) throws
> > RemoteStorageException;
> >
> > That makes sense to me, updated the KIP.
> >
> > 6003: Could you also update the javadoc for the return value?
> >
> > Updated.
> >
> > 6020: local.log.retention.bytes: Should it default to log.retention.bytes
> > to be consistent with local.log.retention.ms?
> >
> > Yes, it can be defaulted to log.retention.bytes.
> >
> > 6021: Could you define TopicIdPartition?
> >
> > Added TopicIdPartition in the KIP.
> >
> > 6022: For all public facing classes, could you specify the package name?
> >
> > Updated.
> >
> >
> > Thanks,
> > Satish.
> >
> > On Tue, Dec 8, 2020 at 12:59 AM Jun Rao <ju...@confluent.io> wrote:
> > >
> > > Hi, Satish,
> > >
> > > Thanks for the reply. A few more comments below.
> > >
> > > 5102.2: It seems that both positions can just be int. Another option is
> > to
> > > have two methods. Would it be clearer?
> > >
> > >     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> > > remoteLogSegmentMetadata,
> > >                                     int startPosition) throws
> > > RemoteStorageException;
> > >
> > >     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> > > remoteLogSegmentMetadata,
> > >                                     int startPosition, int endPosition)
> > > throws RemoteStorageException;
> > >
> > > 6003: Could you also update the javadoc for the return value?
> > >
> > > 6010: What kind of tiering throughput have you seen with 5 threads?
> > >
> > > 6020: local.log.retention.bytes: Should it default to log.retention.bytes
> > > to be consistent with local.log.retention.ms?
> > >
> > > 6021: Could you define TopicIdPartition?
> > >
> > > 6022: For all public facing classes, could you specify the package name?
> > >
> > > It seems that you already added the topicId support. Two other remaining
> > > items are (a) the format of local tier metadata storage and (b) upgrade.
> > >
> > > Jun
> > >
> > > On Mon, Dec 7, 2020 at 8:56 AM Satish Duggana <sa...@gmail.com>
> > > wrote:
> > >
> > > > Hi Jun,
> > > > Thanks for your comments. Please find the inline replies below.
> > > >
> > > > >605.2 It's rare for the follower to need the remote data. So, the
> > current
> > > > approach is fine too. Could you document the process of rebuilding the
> > > > producer state since we can't simply trim the producerState to an
> > offset in
> > > > the middle of a segment.
> > > >
> > > > Will clarify in the KIP.
> > > >
> > > > >5102.2 Would it be clearer to make startPosiont long and endPosition
> > of
> > > > Optional<Long>?
> > > >
> > > > We will have arg checks with respective validation. It is not a good
> > > > practice to have arguments with optional as mentioned here.
> > > > https://rules.sonarsource.com/java/RSPEC-3553
> > > >
> > > >
> > > > >5102.5 LogSegmentData still has leaderEpochIndex as File instead of
> > > > ByteBuffer.
> > > >
> > > > Updated.
> > > >
> > > > >5102.7 Could you define all public methods for LogSegmentData?
> > > >
> > > > Updated.
> > > >
> > > > >5103.5 Could you change the reference to rlm_process_interval_ms and
> > > > rlm_retry_interval_ms to the new config names? Also, the retry interval
> > > > config seems still missing. It would be useful to support exponential
> > > > backoff with the retry interval config.
> > > >
> > > > Good point. We wanted the retry with truncated exponential backoff,
> > > > updated the KIP.
> > > >
> > > > >5111. "RLM follower fetches the earliest offset for the earliest
> > leader
> > > > epoch by calling RLMM.earliestLogOffset(TopicPartition topicPartition,
> > int
> > > > leaderEpoch) and updates that as the log start offset." This text is
> > still
> > > > there. Also, could we remove earliestLogOffset() from RLMM?
> > > >
> > > > Updated.
> > > >
> > > > >5115. There are still references to "remote log cleaners".
> > > >
> > > > Updated.
> > > >
> > > > >6000. Since we are returning new error codes, we need to bump up the
> > > > protocol version for Fetch request. Also, it will be useful to
> > document all
> > > > new error codes and whether they are retriable or not.
> > > >
> > > > Sure, we will add that in the KIP.
> > > >
> > > > >6001. public Map<Long, Long> segmentLeaderEpochs(): Currently,
> > leaderEpoch
> > > > is int32 instead of long.
> > > >
> > > > Updated.
> > > >
> > > > >6002. Is RemoteLogSegmentMetadata.markedForDeletion() needed given
> > > > RemoteLogSegmentMetadata.state()?
> > > >
> > > > No, it is fixed.
> > > >
> > > > >6003. RemoteLogSegmentMetadata remoteLogSegmentMetadata(TopicPartition
> > > > topicPartition, long offset, int epochForOffset): Should this return
> > > > Optional<RemoteLogSegmentMetadata>?
> > > >
> > > > That makes sense, updated.
> > > >
> > > > >6005. RemoteLogState: It seems it's better to split it between
> > > > DeletePartitionUpdate and RemoteLogSegmentMetadataUpdate since the
> > states
> > > > are never shared between the two use cases.
> > > >
> > > > Agree with that, updated.
> > > >
> > > > >6006. RLMM.onPartitionLeadershipChanges(): This may be ok. However,
> > is it
> > > > ture that other than the metadata topic, RLMM just needs to know
> > whether
> > > > there is a replica assigned to this broker and doesn't need to know
> > whether
> > > > the replica is the leader or the follower?
> > > >
> > > > That may be true. If the implementation does not need that, it can
> > > > ignore the information in the callback.
> > > >
> > > > >6007: "Handle expired remote segments (leader and follower)": Why is
> > this
> > > > needed in both the leader and the follower?
> > > >
> > > > Updated.
> > > >
> > > > >6008.       "name": "SegmentSizeInBytes",
> > > >                 "type": "int64",
> > > > The segment size can just be int32.
> > > >
> > > > Updated.
> > > >
> > > > >6009. For the record format in the log, it seems that we need to add
> > > > record
> > > > type and record version before the serialized bytes. We can follow the
> > > > convention used in
> > > >
> > > >
> > https://cwiki.apache.org/confluence/display/KAFKA/KIP-631%3A+The+Quorum-based+Kafka+Controller#KIP631:TheQuorumbasedKafkaController-RecordFormats
> > > >
> > > > Yes, KIP already mentions that these are serialized before the payload
> > > > as below. We will mention explicitly that these two are written before
> > > > the data is written.
> > > >
> > > > RLMM instance on broker publishes the message to the topic with key as
> > > > null and value with the below format.
> > > >
> > > > type      : unsigned var int, represents the value type. This value is
> > > > 'apikey' as mentioned in the schema.
> > > > version : unsigned var int, the 'version' number of the type as
> > > > mentioned in the schema.
> > > > data      : record payload in kafka protocol message format.
> > > >
> > > >
> > > > >6010. remote.log.manager.thread.pool.size: The default value is 10.
> > This
> > > > might be too high when enabling the tiered feature for the first time.
> > > > Since there are lots of segments that need to be tiered initially, a
> > large
> > > > number of threads could overwhelm the broker.
> > > >
> > > > Is the default value 5 reasonable?
> > > >
> > > > 6011. "The number of milli seconds to keep the local log segment
> > before it
> > > > gets deleted. If not set, the value in `log.retention.minutes` is
> > used. If
> > > > set to -1, no time limit is applied." We should use log.retention.ms
> > > > instead of log.retention.minutes.
> > > > Nice typo catch. Updated the KIP.
> > > >
> > > > Thanks,
> > > > Satish.
> > > >
> > > > On Thu, Dec 3, 2020 at 8:03 AM Jun Rao <ju...@confluent.io> wrote:
> > > > >
> > > > > Hi, Satish,
> > > > >
> > > > > Thanks for the updated KIP. A few more comments below.
> > > > >
> > > > > 605.2 It's rare for the follower to need the remote data. So, the
> > current
> > > > > approach is fine too. Could you document the process of rebuilding
> > the
> > > > > producer state since we can't simply trim the producerState to an
> > offset
> > > > in
> > > > > the middle of a segment.
> > > > >
> > > > > 5102.2 Would it be clearer to make startPosiont long and endPosition
> > of
> > > > > Optional<Long>?
> > > > >
> > > > > 5102.5 LogSegmentData still has leaderEpochIndex as File instead of
> > > > > ByteBuffer.
> > > > >
> > > > > 5102.7 Could you define all public methods for LogSegmentData?
> > > > >
> > > > > 5103.5 Could you change the reference to rlm_process_interval_ms and
> > > > > rlm_retry_interval_ms to the new config names? Also, the retry
> > interval
> > > > > config seems still missing. It would be useful to support exponential
> > > > > backoff with the retry interval config.
> > > > >
> > > > > 5111. "RLM follower fetches the earliest offset for the earliest
> > leader
> > > > > epoch by calling RLMM.earliestLogOffset(TopicPartition
> > topicPartition,
> > > > int
> > > > > leaderEpoch) and updates that as the log start offset." This text is
> > > > still
> > > > > there. Also, could we remove earliestLogOffset() from RLMM?
> > > > >
> > > > > 5115. There are still references to "remote log cleaners".
> > > > >
> > > > > 6000. Since we are returning new error codes, we need to bump up the
> > > > > protocol version for Fetch request. Also, it will be useful to
> > document
> > > > all
> > > > > new error codes and whether they are retriable or not.
> > > > >
> > > > > 6001. public Map<Long, Long> segmentLeaderEpochs(): Currently,
> > > > leaderEpoch
> > > > > is int32 instead of long.
> > > > >
> > > > > 6002. Is RemoteLogSegmentMetadata.markedForDeletion() needed given
> > > > > RemoteLogSegmentMetadata.state()?
> > > > >
> > > > > 6003. RemoteLogSegmentMetadata
> > remoteLogSegmentMetadata(TopicPartition
> > > > > topicPartition, long offset, int epochForOffset): Should this return
> > > > > Optional<RemoteLogSegmentMetadata>?
> > > > >
> > > > > 6004. DeletePartitionUpdate.epoch(): It would be useful to pick a
> > more
> > > > > indicative name so that people understand what epoch this is.
> > > > >
> > > > > 6005. RemoteLogState: It seems it's better to split it between
> > > > > DeletePartitionUpdate and RemoteLogSegmentMetadataUpdate since the
> > states
> > > > > are never shared between the two use cases.
> > > > >
> > > > > 6006. RLMM.onPartitionLeadershipChanges(): This may be ok. However,
> > is it
> > > > > ture that other than the metadata topic, RLMM just needs to know
> > whether
> > > > > there is a replica assigned to this broker and doesn't need to know
> > > > whether
> > > > > the replica is the leader or the follower?
> > > > >
> > > > > 6007: "Handle expired remote segments (leader and follower)": Why is
> > this
> > > > > needed in both the leader and the follower?
> > > > >
> > > > > 6008.       "name": "SegmentSizeInBytes",
> > > > >                 "type": "int64",
> > > > > The segment size can just be int32.
> > > > >
> > > > > 6009. For the record format in the log, it seems that we need to add
> > > > record
> > > > > type and record version before the serialized bytes. We can follow
> > the
> > > > > convention used in
> > > > >
> > > >
> > https://cwiki.apache.org/confluence/display/KAFKA/KIP-631%3A+The+Quorum-based+Kafka+Controller#KIP631:TheQuorumbasedKafkaController-RecordFormats
> > > > > .
> > > > >
> > > > > 6010. remote.log.manager.thread.pool.size: The default value is 10.
> > This
> > > > > might be too high when enabling the tiered feature for the first
> > time.
> > > > > Since there are lots of segments that need to be tiered initially, a
> > > > large
> > > > > number of threads could overwhelm the broker.
> > > > >
> > > > > 6011. "The number of milli seconds to keep the local log segment
> > before
> > > > it
> > > > > gets deleted. If not set, the value in `log.retention.minutes` is
> > used.
> > > > If
> > > > > set to -1, no time limit is applied." We should use log.retention.ms
> > > > > instead of log.retention.minutes.
> > > > >
> > > > > Jun
> > > > >
> > > > > On Tue, Dec 1, 2020 at 2:42 AM Satish Duggana <
> > satish.duggana@gmail.com>
> > > > > wrote:
> > > > >
> > > > > > Hi,
> > > > > > We updated the KIP with the points mentioned in the earlier mail
> > > > > > except for KIP-516 related changes. You can go through them and
> > let us
> > > > > > know if you have any comments. We will update the KIP with the
> > > > > > remaining todo items and KIP-516 related changes by end of this
> > > > > > week(5th Dec).
> > > > > >
> > > > > > Thanks,
> > > > > > Satish.
> > > > > >
> > > > > > On Tue, Nov 10, 2020 at 8:26 PM Satish Duggana <
> > > > satish.duggana@gmail.com>
> > > > > > wrote:
> > > > > > >
> > > > > > > Hi Jun,
> > > > > > > Thanks for your comments. Please find the inline replies below.
> > > > > > >
> > > > > > > 605.2 "Build the local leader epoch cache by cutting the leader
> > epoch
> > > > > > > sequence received from remote storage to [LSO, ELO]." I
> > mentioned an
> > > > > > issue
> > > > > > > earlier. Suppose the leader's local start offset is 100. The
> > follower
> > > > > > finds
> > > > > > > a remote segment covering offset range [80, 120). The
> > producerState
> > > > with
> > > > > > > this remote segment is up to offset 120. To trim the
> > producerState to
> > > > > > > offset 100 requires more work since one needs to download the
> > > > previous
> > > > > > > producerState up to offset 80 and then replay the messages from
> > 80 to
> > > > > > 100.
> > > > > > > It seems that it's simpler in this case for the follower just to
> > > > take the
> > > > > > > remote segment as it is and start fetching from offset 120.
> > > > > > >
> > > > > > > We chose that approach to avoid any edge cases here. It may be
> > > > > > > possible that the remote log segment that is received may not
> > have
> > > > the
> > > > > > > same leader epoch sequence from 100-120 as it contains on the
> > > > > > > leader(this can happen due to unclean leader). It is safe to
> > start
> > > > > > > from what the leader returns here.Another way is to find the
> > remote
> > > > > > > log segment
> > > > > > >
> > > > > > > 5016. Just to echo what Kowshik was saying. It seems that
> > > > > > > RLMM.onPartitionLeadershipChanges() is only called on the
> > replicas
> > > > for a
> > > > > > > partition, not on the replicas for the
> > __remote_log_segment_metadata
> > > > > > > partition. It's not clear how the leader of
> > > > __remote_log_segment_metadata
> > > > > > > obtains the metadata for remote segments for deletion.
> > > > > > >
> > > > > > > RLMM will always receive the callback for the remote log metadata
> > > > > > > topic partitions hosted on the local broker and these will be
> > > > > > > subscribed. I will make this clear in the KIP.
> > > > > > >
> > > > > > > 5100. KIP-516 has been accepted and is being implemented now.
> > Could
> > > > you
> > > > > > > update the KIP based on topicID?
> > > > > > >
> > > > > > > We mentioned KIP-516 and how it helps. We will update this KIP
> > with
> > > > > > > all the changes it brings with KIP-516.
> > > > > > >
> > > > > > > 5101. RLMM: It would be useful to clarify how the following two
> > APIs
> > > > are
> > > > > > > used. According to the wiki, the former is used for topic
> > deletion
> > > > and
> > > > > > the
> > > > > > > latter is used for retention. It seems that retention should use
> > the
> > > > > > former
> > > > > > > since remote segments without a matching epoch in the leader
> > > > (potentially
> > > > > > > due to unclean leader election) also need to be garbage
> > collected.
> > > > The
> > > > > > > latter seems to be used for the new leader to determine the last
> > > > tiered
> > > > > > > segment.
> > > > > > >     default Iterator<RemoteLogSegmentMetadata>
> > > > > > > listRemoteLogSegments(TopicPartition topicPartition)
> > > > > > >     Iterator<RemoteLogSegmentMetadata>
> > > > > > listRemoteLogSegments(TopicPartition
> > > > > > > topicPartition, long leaderEpoch);
> > > > > > >
> > > > > > > Right,.that is what we are currently doing. We will update the
> > > > > > > javadocs and wiki with that. Earlier, we did not want to remove
> > the
> > > > > > > segments which are not matched with leader epochs from the ladder
> > > > > > > partition as they may be used later by a replica which can
> > become a
> > > > > > > leader (unclean leader election) and refer those segments. But
> > that
> > > > > > > may leak these segments in remote storage until the topic
> > lifetime.
> > > > We
> > > > > > > decided to cleanup the segments with the oldest incase of size
> > based
> > > > > > > retention also.
> > > > > > >
> > > > > > > 5102. RSM:
> > > > > > > 5102.1 For methods like fetchLogSegmentData(), it seems that
> > they can
> > > > > > > use RemoteLogSegmentId instead of RemoteLogSegmentMetadata.
> > > > > > >
> > > > > > > It will be useful to have metadata for RSM to fetch log segment.
> > It
> > > > > > > may create location/path using id with other metadata too.
> > > > > > >
> > > > > > > 5102.2 In fetchLogSegmentData(), should we use long instead of
> > Long?
> > > > > > >
> > > > > > > Wanted to keep endPosition as optional to read till the end of
> > the
> > > > > > > segment and avoid sentinels.
> > > > > > >
> > > > > > > 5102.3 Why only some of the methods have default implementation
> > and
> > > > > > others
> > > > > > > Don't?
> > > > > > >
> > > > > > > Actually,  RSM will not have any default implementations. Those 3
> > > > > > > methods were made default earlier for tests etc. Updated the
> > wiki.
> > > > > > >
> > > > > > > 5102.4. Could we define RemoteLogSegmentMetadataUpdate
> > > > > > > and DeletePartitionUpdate?
> > > > > > >
> > > > > > > Sure, they will be added.
> > > > > > >
> > > > > > >
> > > > > > > 5102.5 LogSegmentData: It seems that it's easier to pass
> > > > > > > in leaderEpochIndex as a ByteBuffer or byte array than a file
> > since
> > > > it
> > > > > > will
> > > > > > > be generated in memory.
> > > > > > >
> > > > > > > Right, this is in plan.
> > > > > > >
> > > > > > > 5102.6 RemoteLogSegmentMetadata: It seems that it needs both
> > > > baseOffset
> > > > > > and
> > > > > > > startOffset. For example, deleteRecords() could move the
> > startOffset
> > > > to
> > > > > > the
> > > > > > > middle of a segment. If we copy the full segment to remote
> > storage,
> > > > the
> > > > > > > baseOffset and the startOffset will be different.
> > > > > > >
> > > > > > > Good point. startOffset is baseOffset by default, if not set
> > > > explicitly.
> > > > > > >
> > > > > > > 5102.7 Could we define all the public methods for
> > > > > > RemoteLogSegmentMetadata
> > > > > > > and LogSegmentData?
> > > > > > >
> > > > > > > Sure, updated the wiki.
> > > > > > >
> > > > > > > 5102.8 Could we document whether endOffset in
> > > > RemoteLogSegmentMetadata is
> > > > > > > inclusive/exclusive?
> > > > > > >
> > > > > > > It is inclusive, will update.
> > > > > > >
> > > > > > > 5103. configs:
> > > > > > > 5103.1 Could we define the default value of non-required configs
> > > > (e.g the
> > > > > > > size of new thread pools)?
> > > > > > >
> > > > > > > Sure, that makes sense.
> > > > > > >
> > > > > > > 5103.2 It seems that local.log.retention.ms should default to
> > > > > > retention.ms,
> > > > > > > instead of remote.log.retention.minutes. Similarly, it seems
> > > > > > > that local.log.retention.bytes should default to segment.bytes.
> > > > > > >
> > > > > > > Right, we do not have  remote.log.retention as we discussed
> > earlier.
> > > > > > > Thanks for catching the typo.
> > > > > > >
> > > > > > > 5103.3 remote.log.manager.thread.pool.size: The description says
> > > > "used in
> > > > > > > scheduling tasks to copy segments, fetch remote log indexes and
> > > > clean up
> > > > > > > remote log segments". However, there is a separate
> > > > > > > config remote.log.reader.threads for fetching remote data. It's
> > > > weird to
> > > > > > > fetch remote index and log in different thread pools since both
> > are
> > > > used
> > > > > > > for serving fetch requests.
> > > > > > >
> > > > > > > Right, remote.log.manager.thread.pool is mainly used for
> > copy/cleanup
> > > > > > > activities. Fetch path always goes through
> > remote.log.reader.threads.
> > > > > > >
> > > > > > > 5103.4 remote.log.manager.task.interval.ms: Is that the amount
> > of
> > > > time
> > > > > > to
> > > > > > > back off when there is no work to do? If so, perhaps it can be
> > > > renamed as
> > > > > > > backoff.ms.
> > > > > > >
> > > > > > > This is the delay interval for each iteration. It may be renamed
> > to
> > > > > > > remote.log.manager.task.delay.ms
> > > > > > >
> > > > > > > 5103.5 Are rlm_process_interval_ms and rlm_retry_interval_ms
> > > > configs? If
> > > > > > > so, they need to be listed in this section.
> > > > > > >
> > > > > > > remote.log.manager.task.interval.ms is the process internal,
> > retry
> > > > > > > interval is missing in the configs, which will be updated in the
> > KIP.
> > > > > > >
> > > > > > > 5104. "RLM maintains a bounded cache(possibly LRU) of the index
> > > > files of
> > > > > > > remote log segments to avoid multiple index fetches from the
> > remote
> > > > > > > storage." Is the RLM in memory or on disk? If on disk, where is
> > it
> > > > > > stored?
> > > > > > > Do we need a configuration to bound the size?
> > > > > > >
> > > > > > > It is stored on disk. They are stored in a directory
> > > > > > > `remote-log-index-cache` under log dir. We plan to have a config
> > for
> > > > > > > that instead of default. We will have a configuration for that.
> > > > > > >
> > > > > > > 5105. The KIP uses local-log-start-offset and Earliest Local
> > Offset
> > > > in
> > > > > > > different places. It would be useful to standardize the
> > terminology.
> > > > > > >
> > > > > > > Sure.
> > > > > > >
> > > > > > > 5106. The section on "In BuildingRemoteLogAux state". It listed
> > two
> > > > > > options
> > > > > > > without saying which option is chosen.
> > > > > > > We already mentioned in the KIP that we chose option-2.
> > > > > > >
> > > > > > > 5107. Follower to leader transition: It has step 2, but not step
> > 1.
> > > > > > > Step-1 is there but it is not explicitly highlighted. It is
> > previous
> > > > > > > table to step-2.
> > > > > > >
> > > > > > > 5108. If a consumer fetches from the remote data and the remote
> > > > storage
> > > > > > is
> > > > > > > not available, what error code is used in the fetch response?
> > > > > > >
> > > > > > > Good point. We have not yet defined the error for this case. We
> > need
> > > > > > > to define an error message and send the same in fetch response.
> > > > > > >
> > > > > > > 5109. "ListOffsets: For timestamps >= 0, it returns the first
> > message
> > > > > > > offset whose timestamp is >= to the given timestamp in the
> > request.
> > > > That
> > > > > > > means it checks in remote log time indexes first, after which
> > local
> > > > log
> > > > > > > time indexes are checked." Could you document which method in
> > RLMM is
> > > > > > used
> > > > > > > for this?
> > > > > > >
> > > > > > > Okay.
> > > > > > >
> > > > > > > 5110. Stopreplica: "it sets all the remote log segment metadata
> > of
> > > > that
> > > > > > > partition with a delete marker and publishes them to RLMM." This
> > > > seems
> > > > > > > outdated given the new topic deletion logic.
> > > > > > >
> > > > > > > Will update with KIP-516 related points.
> > > > > > >
> > > > > > > 5111. "RLM follower fetches the earliest offset for the earliest
> > > > leader
> > > > > > > epoch by calling RLMM.earliestLogOffset(TopicPartition
> > > > topicPartition,
> > > > > > int
> > > > > > > leaderEpoch) and updates that as the log start offset." Do we
> > need
> > > > that
> > > > > > > since replication propagates logStartOffset already?
> > > > > > >
> > > > > > > Good point. Right, existing replication protocol takes care of
> > > > > > > updating the followers’s log start offset received from the
> > leader.
> > > > > > >
> > > > > > > 5112. Is the default maxWaitMs of 500ms enough for fetching from
> > > > remote
> > > > > > > storage?
> > > > > > >
> > > > > > > Remote reads may fail within the current default wait time, but
> > > > > > > subsequent fetches would be able to serve as that data is stored
> > in
> > > > > > > the local cache. This cache is currently implemented in RSMs.
> > But we
> > > > > > > plan to pull this into the remote log messaging layer in future.
> > > > > > >
> > > > > > > 5113. "Committed offsets can be stored in a local file to avoid
> > > > reading
> > > > > > the
> > > > > > > messages again when a broker is restarted." Could you describe
> > the
> > > > format
> > > > > > > and the location of the file? Also, could the same message be
> > > > processed
> > > > > > by
> > > > > > > RLMM again after broker restart? If so, how do we handle that?
> > > > > > >
> > > > > > > Sure, we will update in the KIP.
> > > > > > >
> > > > > > > 5114. Message format
> > > > > > > 5114.1 There are two records named RemoteLogSegmentMetadataRecord
> > > > with
> > > > > > > apiKey 0 and 1.
> > > > > > >
> > > > > > > Nice catch, that was a typo. Fixed in the wiki.
> > > > > > >
> > > > > > > 5114.2 RemoteLogSegmentMetadataRecord: Could we document whether
> > > > > > endOffset
> > > > > > > is inclusive/exclusive?
> > > > > > > It is inclusive, will update.
> > > > > > >
> > > > > > > 5114.3 RemoteLogSegmentMetadataRecord: Could you explain
> > LeaderEpoch
> > > > a
> > > > > > bit
> > > > > > > more? Is that the epoch of the leader when it copies the segment
> > to
> > > > > > remote
> > > > > > > storage? Also, how will this field be used?
> > > > > > >
> > > > > > > Right, this is the leader epoch of the broker which copied this
> > > > > > > segment. This is helpful in reason about which broker copied the
> > > > > > > segment to remote storage.
> > > > > > >
> > > > > > > 5114.4 EventTimestamp: Could you explain this a bit more? Each
> > > > record in
> > > > > > > Kafka already has a timestamp field. Could we just use that?
> > > > > > >
> > > > > > > This is the  timestamp at which  the respective event occurred.
> > Added
> > > > > > > this  to RemoteLogSegmentMetadata as RLMM can be  any other
> > > > > > > implementation. We thought about that but it looked cleaner to
> > use at
> > > > > > > the message structure level instead of getting that from the
> > consumer
> > > > > > > record and using that to build the respective event.
> > > > > > >
> > > > > > >
> > > > > > > 5114.5 SegmentSizeInBytes: Could this just be int32?
> > > > > > >
> > > > > > > Right, it looks like config allows only int value >= 14.
> > > > > > >
> > > > > > > 5115. RemoteLogCleaner(RLC): This could be confused with the log
> > > > cleaner
> > > > > > > for compaction. Perhaps it can be renamed to sth like
> > > > > > > RemotePartitionRemover.
> > > > > > >
> > > > > > > I am fine with RemotePartitionRemover or
> > RemoteLogDeletionManager(we
> > > > > > > have other manager classes like RLM, RLMM).
> > > > > > >
> > > > > > > 5116. "RLC receives the delete_partition_marked and processes it
> > if
> > > > it is
> > > > > > > not yet processed earlier." How does it know whether
> > > > > > > delete_partition_marked has been processed earlier?
> > > > > > >
> > > > > > > This is to handle duplicate delete_partition_marked events. RLC
> > > > > > > internally maintains a state for the delete_partition events and
> > if
> > > > it
> > > > > > > already has an existing event then it ignores if it is already
> > being
> > > > > > > processed.
> > > > > > >
> > > > > > > 5117. Should we add a new MessageFormatter to read the tier
> > metadata
> > > > > > topic?
> > > > > > >
> > > > > > > Right, this is in plan but did not mention it in the KIP. This
> > will
> > > > be
> > > > > > > useful for debugging purposes too.
> > > > > > >
> > > > > > > 5118. "Maximum remote log reader thread pool task queue size. If
> > the
> > > > task
> > > > > > > queue is full, broker will stop reading remote log segments."
> > What
> > > > do we
> > > > > > > return to the fetch request in this case?
> > > > > > >
> > > > > > > We return an error response for that partition.
> > > > > > >
> > > > > > > 5119. It would be useful to list all things not supported in the
> > > > first
> > > > > > > version in a Future work or Limitations section. For example,
> > > > compacted
> > > > > > > topic, JBOD, changing remote.log.storage.enable from true to
> > false,
> > > > etc.
> > > > > > >
> > > > > > > We already have a non-goals section which is filled with some of
> > > > these
> > > > > > > details. Do we need another limitations section?
> > > > > > >
> > > > > > > Thanks,
> > > > > > > Satish.
> > > > > > >
> > > > > > > On Wed, Nov 4, 2020 at 11:27 PM Jun Rao <ju...@confluent.io>
> > wrote:
> > > > > > > >
> > > > > > > > Hi, Satish,
> > > > > > > >
> > > > > > > > Thanks for the updated KIP. A few more comments below.
> > > > > > > >
> > > > > > > > 605.2 "Build the local leader epoch cache by cutting the leader
> > > > epoch
> > > > > > > > sequence received from remote storage to [LSO, ELO]." I
> > mentioned
> > > > an
> > > > > > issue
> > > > > > > > earlier. Suppose the leader's local start offset is 100. The
> > > > follower
> > > > > > finds
> > > > > > > > a remote segment covering offset range [80, 120). The
> > producerState
> > > > > > with
> > > > > > > > this remote segment is up to offset 120. To trim the
> > producerState
> > > > to
> > > > > > > > offset 100 requires more work since one needs to download the
> > > > previous
> > > > > > > > producerState up to offset 80 and then replay the messages
> > from 80
> > > > to
> > > > > > 100.
> > > > > > > > It seems that it's simpler in this case for the follower just
> > to
> > > > take
> > > > > > the
> > > > > > > > remote segment as it is and start fetching from offset 120.
> > > > > > > >
> > > > > > > > 5016. Just to echo what Kowshik was saying. It seems that
> > > > > > > > RLMM.onPartitionLeadershipChanges() is only called on the
> > replicas
> > > > for
> > > > > > a
> > > > > > > > partition, not on the replicas for the
> > > > __remote_log_segment_metadata
> > > > > > > > partition. It's not clear how the leader of
> > > > > > __remote_log_segment_metadata
> > > > > > > > obtains the metadata for remote segments for deletion.
> > > > > > > >
> > > > > > > > 5100. KIP-516 has been accepted and is being implemented now.
> > > > Could you
> > > > > > > > update the KIP based on topicID?
> > > > > > > >
> > > > > > > > 5101. RLMM: It would be useful to clarify how the following two
> > > > APIs
> > > > > > are
> > > > > > > > used. According to the wiki, the former is used for topic
> > deletion
> > > > and
> > > > > > the
> > > > > > > > latter is used for retention. It seems that retention should
> > use
> > > > the
> > > > > > former
> > > > > > > > since remote segments without a matching epoch in the leader
> > > > > > (potentially
> > > > > > > > due to unclean leader election) also need to be garbage
> > collected.
> > > > The
> > > > > > > > latter seems to be used for the new leader to determine the
> > last
> > > > tiered
> > > > > > > > segment.
> > > > > > > >     default Iterator<RemoteLogSegmentMetadata>
> > > > > > > > listRemoteLogSegments(TopicPartition topicPartition)
> > > > > > > >     Iterator<RemoteLogSegmentMetadata>
> > > > > > listRemoteLogSegments(TopicPartition
> > > > > > > > topicPartition, long leaderEpoch);
> > > > > > > >
> > > > > > > > 5102. RSM:
> > > > > > > > 5102.1 For methods like fetchLogSegmentData(), it seems that
> > they
> > > > can
> > > > > > > > use RemoteLogSegmentId instead of RemoteLogSegmentMetadata.
> > > > > > > > 5102.2 In fetchLogSegmentData(), should we use long instead of
> > > > Long?
> > > > > > > > 5102.3 Why only some of the methods have default
> > implementation and
> > > > > > others
> > > > > > > > don't?
> > > > > > > > 5102.4. Could we define RemoteLogSegmentMetadataUpdate
> > > > > > > > and DeletePartitionUpdate?
> > > > > > > > 5102.5 LogSegmentData: It seems that it's easier to pass
> > > > > > > > in leaderEpochIndex as a ByteBuffer or byte array than a file
> > > > since it
> > > > > > will
> > > > > > > > be generated in memory.
> > > > > > > > 5102.6 RemoteLogSegmentMetadata: It seems that it needs both
> > > > > > baseOffset and
> > > > > > > > startOffset. For example, deleteRecords() could move the
> > > > startOffset
> > > > > > to the
> > > > > > > > middle of a segment. If we copy the full segment to remote
> > > > storage, the
> > > > > > > > baseOffset and the startOffset will be different.
> > > > > > > > 5102.7 Could we define all the public methods for
> > > > > > RemoteLogSegmentMetadata
> > > > > > > > and LogSegmentData?
> > > > > > > > 5102.8 Could we document whether endOffset in
> > > > RemoteLogSegmentMetadata
> > > > > > is
> > > > > > > > inclusive/exclusive?
> > > > > > > >
> > > > > > > > 5103. configs:
> > > > > > > > 5103.1 Could we define the default value of non-required
> > configs
> > > > (e.g
> > > > > > the
> > > > > > > > size of new thread pools)?
> > > > > > > > 5103.2 It seems that local.log.retention.ms should default to
> > > > > > retention.ms,
> > > > > > > > instead of remote.log.retention.minutes. Similarly, it seems
> > > > > > > > that local.log.retention.bytes should default to segment.bytes.
> > > > > > > > 5103.3 remote.log.manager.thread.pool.size: The description
> > says
> > > > "used
> > > > > > in
> > > > > > > > scheduling tasks to copy segments, fetch remote log indexes and
> > > > clean
> > > > > > up
> > > > > > > > remote log segments". However, there is a separate
> > > > > > > > config remote.log.reader.threads for fetching remote data. It's
> > > > weird
> > > > > > to
> > > > > > > > fetch remote index and log in different thread pools since
> > both are
> > > > > > used
> > > > > > > > for serving fetch requests.
> > > > > > > > 5103.4 remote.log.manager.task.interval.ms: Is that the
> > amount of
> > > > > > time to
> > > > > > > > back off when there is no work to do? If so, perhaps it can be
> > > > renamed
> > > > > > as
> > > > > > > > backoff.ms.
> > > > > > > > 5103.5 Are rlm_process_interval_ms and rlm_retry_interval_ms
> > > > configs?
> > > > > > If
> > > > > > > > so, they need to be listed in this section.
> > > > > > > >
> > > > > > > > 5104. "RLM maintains a bounded cache(possibly LRU) of the index
> > > > files
> > > > > > of
> > > > > > > > remote log segments to avoid multiple index fetches from the
> > remote
> > > > > > > > storage." Is the RLM in memory or on disk? If on disk, where
> > is it
> > > > > > stored?
> > > > > > > > Do we need a configuration to bound the size?
> > > > > > > >
> > > > > > > > 5105. The KIP uses local-log-start-offset and Earliest Local
> > > > Offset in
> > > > > > > > different places. It would be useful to standardize the
> > > > terminology.
> > > > > > > >
> > > > > > > > 5106. The section on "In BuildingRemoteLogAux state". It
> > listed two
> > > > > > options
> > > > > > > > without saying which option is chosen.
> > > > > > > >
> > > > > > > > 5107. Follower to leader transition: It has step 2, but not
> > step 1.
> > > > > > > >
> > > > > > > > 5108. If a consumer fetches from the remote data and the remote
> > > > > > storage is
> > > > > > > > not available, what error code is used in the fetch response?
> > > > > > > >
> > > > > > > > 5109. "ListOffsets: For timestamps >= 0, it returns the first
> > > > message
> > > > > > > > offset whose timestamp is >= to the given timestamp in the
> > request.
> > > > > > That
> > > > > > > > means it checks in remote log time indexes first, after which
> > > > local log
> > > > > > > > time indexes are checked." Could you document which method in
> > RLMM
> > > > is
> > > > > > used
> > > > > > > > for this?
> > > > > > > >
> > > > > > > > 5110. Stopreplica: "it sets all the remote log segment
> > metadata of
> > > > that
> > > > > > > > partition with a delete marker and publishes them to RLMM."
> > This
> > > > seems
> > > > > > > > outdated given the new topic deletion logic.
> > > > > > > >
> > > > > > > > 5111. "RLM follower fetches the earliest offset for the
> > earliest
> > > > leader
> > > > > > > > epoch by calling RLMM.earliestLogOffset(TopicPartition
> > > > topicPartition,
> > > > > > int
> > > > > > > > leaderEpoch) and updates that as the log start offset." Do we
> > need
> > > > that
> > > > > > > > since replication propagates logStartOffset already?
> > > > > > > >
> > > > > > > > 5112. Is the default maxWaitMs of 500ms enough for fetching
> > from
> > > > remote
> > > > > > > > storage?
> > > > > > > >
> > > > > > > > 5113. "Committed offsets can be stored in a local file to avoid
> > > > > > reading the
> > > > > > > > messages again when a broker is restarted." Could you describe
> > the
> > > > > > format
> > > > > > > > and the location of the file? Also, could the same message be
> > > > > > processed by
> > > > > > > > RLMM again after broker restart? If so, how do we handle that?
> > > > > > > >
> > > > > > > > 5114. Message format
> > > > > > > > 5114.1 There are two records named
> > RemoteLogSegmentMetadataRecord
> > > > with
> > > > > > > > apiKey 0 and 1.
> > > > > > > > 5114.2 RemoteLogSegmentMetadataRecord: Could we document
> > whether
> > > > > > endOffset
> > > > > > > > is inclusive/exclusive?
> > > > > > > > 5114.3 RemoteLogSegmentMetadataRecord: Could you explain
> > > > LeaderEpoch a
> > > > > > bit
> > > > > > > > more? Is that the epoch of the leader when it copies the
> > segment to
> > > > > > remote
> > > > > > > > storage? Also, how will this field be used?
> > > > > > > > 5114.4 EventTimestamp: Could you explain this a bit more? Each
> > > > record
> > > > > > in
> > > > > > > > Kafka already has a timestamp field. Could we just use that?
> > > > > > > > 5114.5 SegmentSizeInBytes: Could this just be int32?
> > > > > > > >
> > > > > > > > 5115. RemoteLogCleaner(RLC): This could be confused with the
> > log
> > > > > > cleaner
> > > > > > > > for compaction. Perhaps it can be renamed to sth like
> > > > > > > > RemotePartitionRemover.
> > > > > > > >
> > > > > > > > 5116. "RLC receives the delete_partition_marked and processes
> > it
> > > > if it
> > > > > > is
> > > > > > > > not yet processed earlier." How does it know whether
> > > > > > > > delete_partition_marked has been processed earlier?
> > > > > > > >
> > > > > > > > 5117. Should we add a new MessageFormatter to read the tier
> > > > metadata
> > > > > > topic?
> > > > > > > >
> > > > > > > > 5118. "Maximum remote log reader thread pool task queue size.
> > If
> > > > the
> > > > > > task
> > > > > > > > queue is full, broker will stop reading remote log segments."
> > What
> > > > do
> > > > > > we
> > > > > > > > return to the fetch request in this case?
> > > > > > > >
> > > > > > > > 5119. It would be useful to list all things not supported in
> > the
> > > > first
> > > > > > > > version in a Future work or Limitations section. For example,
> > > > compacted
> > > > > > > > topic, JBOD, changing remote.log.storage.enable from true to
> > false,
> > > > > > etc.
> > > > > > > >
> > > > > > > > Thanks,
> > > > > > > >
> > > > > > > > Jun
> > > > > > > >
> > > > > > > > On Tue, Oct 27, 2020 at 5:57 PM Kowshik Prakasam <
> > > > > > kprakasam@confluent.io>
> > > > > > > > wrote:
> > > > > > > >
> > > > > > > > > Hi Satish,
> > > > > > > > >
> > > > > > > > > Thanks for the updates to the KIP. Here are my first batch of
> > > > > > > > > comments/suggestions on the latest version of the KIP.
> > > > > > > > >
> > > > > > > > > 5012. In the RemoteStorageManager interface, there is an API
> > > > defined
> > > > > > for
> > > > > > > > > each file type. For example, fetchOffsetIndex,
> > > > fetchTimestampIndex
> > > > > > etc. To
> > > > > > > > > avoid the duplication, I'd suggest we can instead have a
> > FileType
> > > > > > enum and
> > > > > > > > > a common get API based on the FileType.
> > > > > > > > >
> > > > > > > > > 5013. There are some references to the Google doc in the
> > KIP. I
> > > > > > wasn't sure
> > > > > > > > > if the Google doc is expected to be in sync with the
> > contents of
> > > > the
> > > > > > wiki.
> > > > > > > > > Going forward, it seems easier if just the KIP is maintained
> > as
> > > > the
> > > > > > source
> > > > > > > > > of truth. In this regard, could you please move all the
> > > > references
> > > > > > to the
> > > > > > > > > Google doc, maybe to a separate References section at the
> > bottom
> > > > of
> > > > > > the
> > > > > > > > > KIP?
> > > > > > > > >
> > > > > > > > > 5014. There are some TODO sections in the KIP. Would these be
> > > > filled
> > > > > > up in
> > > > > > > > > future iterations?
> > > > > > > > >
> > > > > > > > > 5015. Under "Topic deletion lifecycle", I'm trying to
> > understand
> > > > why
> > > > > > do we
> > > > > > > > > need delete_partition_marked as well as the
> > > > delete_partition_started
> > > > > > > > > messages. I couldn't spot a drawback if supposing we
> > simplified
> > > > the
> > > > > > design
> > > > > > > > > such that the controller would only write
> > > > delete_partition_started
> > > > > > message,
> > > > > > > > > and RemoteLogCleaner (RLC) instance picks it up for
> > processing.
> > > > What
> > > > > > am I
> > > > > > > > > missing?
> > > > > > > > >
> > > > > > > > > 5016. Under "Topic deletion lifecycle", step (4) is
> > mentioned as
> > > > > > "RLC gets
> > > > > > > > > all the remote log segments for the partition and each of
> > these
> > > > > > remote log
> > > > > > > > > segments is deleted with the next steps.". Since the RLC
> > instance
> > > > > > runs on
> > > > > > > > > each tier topic partition leader, how does the RLC then get
> > the
> > > > list
> > > > > > of
> > > > > > > > > remote log segments to be deleted? It will be useful to add
> > that
> > > > > > detail to
> > > > > > > > > the KIP.
> > > > > > > > >
> > > > > > > > > 5017. Under "Public Interfaces -> Configs", there is a line
> > > > > > mentioning "We
> > > > > > > > > will support flipping remote.log.storage.enable in next
> > > > versions."
> > > > > > It will
> > > > > > > > > be useful to mention this in the "Future Work" section of
> > the KIP
> > > > > > too.
> > > > > > > > >
> > > > > > > > > 5018. The KIP introduces a number of configuration
> > parameters. It
> > > > > > will be
> > > > > > > > > useful to mention in the KIP if the user should assume these
> > as
> > > > > > static
> > > > > > > > > configuration in the server.properties file, or dynamic
> > > > > > configuration which
> > > > > > > > > can be modified without restarting the broker.
> > > > > > > > >
> > > > > > > > > 5019.  Maybe this is planned as a future update to the KIP,
> > but I
> > > > > > thought
> > > > > > > > > I'd mention it here. Could you please add details to the KIP
> > on
> > > > why
> > > > > > RocksDB
> > > > > > > > > was chosen as the default cache implementation of RLMM, and
> > how
> > > > it
> > > > > > is going
> > > > > > > > > to be used? Were alternatives compared/considered? For
> > example,
> > > > it
> > > > > > would be
> > > > > > > > > useful to explain/evaluate the following: 1) debuggability
> > of the
> > > > > > RocksDB
> > > > > > > > > JNI interface, 2) performance, 3) portability across
> > platforms
> > > > and 4)
> > > > > > > > > interface parity of RocksDB’s JNI api with it's underlying
> > C/C++
> > > > api.
> > > > > > > > >
> > > > > > > > > 5020. Following up on (5019), for the RocksDB cache, it will
> > be
> > > > > > useful to
> > > > > > > > > explain the relationship/mapping between the following in the
> > > > KIP:
> > > > > > 1) # of
> > > > > > > > > tiered partitions, 2) # of partitions of metadata topic
> > > > > > > > > __remote_log_metadata and 3) # of RocksDB instances. i.e. is
> > the
> > > > > > plan to
> > > > > > > > > have a RocksDB instance per tiered partition, or per metadata
> > > > topic
> > > > > > > > > partition, or just 1 for per broker?
> > > > > > > > >
> > > > > > > > > 5021. I was looking at the implementation prototype (PR link:
> > > > > > > > > https://github.com/apache/kafka/pull/7561). It seems that a
> > > > boolean
> > > > > > > > > attribute is being introduced into the Log layer to check if
> > > > remote
> > > > > > log
> > > > > > > > > capability is enabled. While the boolean footprint is small
> > at
> > > > the
> > > > > > moment,
> > > > > > > > > this can easily grow in the future and become harder to
> > > > > > > > > test/maintain, considering that the Log layer is already
> > pretty
> > > > > > complex. We
> > > > > > > > > should start thinking about how to manage such changes to
> > the Log
> > > > > > layer
> > > > > > > > > (for the purpose of improved testability, better separation
> > of
> > > > > > concerns and
> > > > > > > > > readability). One proposal I have is to take a step back and
> > > > define a
> > > > > > > > > higher level Log interface. Then, the Broker code can be
> > changed
> > > > to
> > > > > > use
> > > > > > > > > this interface. It can be changed such that only a handle to
> > the
> > > > > > interface
> > > > > > > > > is exposed to other components (such as LogCleaner,
> > > > ReplicaManager
> > > > > > etc.)
> > > > > > > > > and not the underlying Log object. This approach keeps the
> > user
> > > > of
> > > > > > the Log
> > > > > > > > > layer agnostic of the whereabouts of the data. Underneath the
> > > > > > interface,
> > > > > > > > > the implementing classes can completely separate local log
> > > > > > capabilities
> > > > > > > > > from the remote log. For example, the Log class can be
> > > > simplified to
> > > > > > only
> > > > > > > > > manage logic surrounding local log segments and metadata.
> > > > > > Additionally, a
> > > > > > > > > wrapper class can be provided (implementing the higher level
> > Log
> > > > > > interface)
> > > > > > > > > which will contain any/all logic surrounding tiered data. The
> > > > wrapper
> > > > > > > > > class will wrap around an instance of the Log class
> > delegating
> > > > the
> > > > > > local
> > > > > > > > > log logic to it. Finally, a handle to the wrapper class can
> > be
> > > > > > exposed to
> > > > > > > > > the other components wherever they need a handle to the
> > higher
> > > > level
> > > > > > Log
> > > > > > > > > interface.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > Cheers,
> > > > > > > > > Kowshik
> > > > > > > > >
> > > > > > > > > On Mon, Oct 26, 2020 at 9:52 PM Satish Duggana <
> > > > > > satish.duggana@gmail.com>
> > > > > > > > > wrote:
> > > > > > > > >
> > > > > > > > > > Hi,
> > > > > > > > > > KIP is updated with 1) topic deletion lifecycle and its
> > related
> > > > > > items
> > > > > > > > > > 2) Protocol changes(mainly related to ListOffsets) and
> > other
> > > > minor
> > > > > > > > > > changes.
> > > > > > > > > > Please go through them and let us know your comments.
> > > > > > > > > >
> > > > > > > > > > Thanks,
> > > > > > > > > > Satish.
> > > > > > > > > >
> > > > > > > > > > On Mon, Sep 28, 2020 at 9:10 PM Satish Duggana <
> > > > > > satish.duggana@gmail.com
> > > > > > > > > >
> > > > > > > > > > wrote:
> > > > > > > > > > >
> > > > > > > > > > > Hi Dhruvil,
> > > > > > > > > > > Thanks for looking into the KIP and sending your
> > comments.
> > > > Sorry
> > > > > > for
> > > > > > > > > > > the late reply, missed it in the mail thread.
> > > > > > > > > > >
> > > > > > > > > > > 1. Could you describe how retention would work with this
> > KIP
> > > > and
> > > > > > which
> > > > > > > > > > > threads are responsible for driving this work? I believe
> > > > there
> > > > > > are 3
> > > > > > > > > > kinds
> > > > > > > > > > > of retention processes we are looking at:
> > > > > > > > > > >   (a) Regular retention for data in tiered storage as per
> > > > > > configured `
> > > > > > > > > > > retention.ms` / `retention.bytes`.
> > > > > > > > > > >   (b) Local retention for data in local storage as per
> > > > > > configured `
> > > > > > > > > > > local.log.retention.ms` / `local.log.retention.bytes`
> > > > > > > > > > >   (c) Possibly regular retention for data in local
> > storage,
> > > > if
> > > > > > the
> > > > > > > > > > tiering
> > > > > > > > > > > task is lagging or for data that is below the log start
> > > > offset.
> > > > > > > > > > >
> > > > > > > > > > > Local log retention is done by the existing log cleanup
> > > > tasks.
> > > > > > These
> > > > > > > > > > > are not done for segments that are not yet copied to
> > remote
> > > > > > storage.
> > > > > > > > > > > Remote log cleanup is done by the leader partition’s
> > RLMTask.
> > > > > > > > > > >
> > > > > > > > > > > 2. When does a segment become eligible to be tiered? Is
> > it as
> > > > > > soon as
> > > > > > > > > the
> > > > > > > > > > > segment is rolled and the end offset is less than the
> > last
> > > > stable
> > > > > > > > > offset
> > > > > > > > > > as
> > > > > > > > > > > mentioned in the KIP? I wonder if we need to consider
> > other
> > > > > > parameters
> > > > > > > > > > too,
> > > > > > > > > > > like the highwatermark so that we are guaranteed that
> > what
> > > > we are
> > > > > > > > > tiering
> > > > > > > > > > > has been committed to the log and accepted by the ISR.
> > > > > > > > > > >
> > > > > > > > > > > AFAIK, last stable offset is always <= highwatermark.
> > This
> > > > will
> > > > > > make
> > > > > > > > > > > sure we are always tiering the message segments which
> > have
> > > > been
> > > > > > > > > > > accepted by ISR and transactionally completed.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > 3. The section on "Follower Fetch Scenarios" is useful
> > but
> > > > is a
> > > > > > bit
> > > > > > > > > > > difficult to parse at the moment. It would be useful to
> > > > > > summarize the
> > > > > > > > > > > changes we need in the ReplicaFetcher.
> > > > > > > > > > >
> > > > > > > > > > > It may become difficult for users to read/follow if we
> > add
> > > > code
> > > > > > changes
> > > > > > > > > > here.
> > > > > > > > > > >
> > > > > > > > > > > 4. Related to the above, it's a bit unclear how we are
> > > > planning
> > > > > > on
> > > > > > > > > > > restoring the producer state for a new replica. Could you
> > > > expand
> > > > > > on
> > > > > > > > > that?
> > > > > > > > > > >
> > > > > > > > > > > It is mentioned in the KIP BuildingRemoteLogAuxState is
> > > > > > introduced to
> > > > > > > > > > > build the state like leader epoch sequence and producer
> > > > snapshots
> > > > > > > > > > > before it starts fetching the data from the leader. We
> > will
> > > > make
> > > > > > it
> > > > > > > > > > > clear in the KIP.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > 5. Similarly, it would be worth summarizing the behavior
> > on
> > > > > > unclean
> > > > > > > > > > leader
> > > > > > > > > > > election. There are several scenarios to consider here:
> > data
> > > > > > loss from
> > > > > > > > > > > local log, data loss from remote log, data loss from
> > metadata
> > > > > > topic,
> > > > > > > > > etc.
> > > > > > > > > > > It's worth describing these in detail.
> > > > > > > > > > >
> > > > > > > > > > > We mentioned the cases about unclean leader election in
> > the
> > > > > > follower
> > > > > > > > > > > fetch scenarios.
> > > > > > > > > > > If there are errors while fetching data from remote
> > store or
> > > > > > metadata
> > > > > > > > > > > store, it will work the same way as it works with local
> > log.
> > > > It
> > > > > > > > > > > returns the error back to the caller. Please let us know
> > if
> > > > I am
> > > > > > > > > > > missing your point here.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > 7. For a READ_COMMITTED FetchRequest, how do we retrieve
> > and
> > > > > > return the
> > > > > > > > > > > aborted transaction metadata?
> > > > > > > > > > >
> > > > > > > > > > > When a fetch for a remote log is accessed, we will fetch
> > > > aborted
> > > > > > > > > > > transactions along with the segment if it is not found
> > in the
> > > > > > local
> > > > > > > > > > > index cache. This includes the case of transaction index
> > not
> > > > > > existing
> > > > > > > > > > > in the remote log segment. That means, the cache entry
> > can be
> > > > > > empty or
> > > > > > > > > > > have a list of aborted transactions.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > 8. The `LogSegmentData` class assumes that we have a log
> > > > segment,
> > > > > > > > > offset
> > > > > > > > > > > index, time index, transaction index, producer snapshot
> > and
> > > > > > leader
> > > > > > > > > epoch
> > > > > > > > > > > index. How do we deal with cases where we do not have
> > one or
> > > > > > more of
> > > > > > > > > > these?
> > > > > > > > > > > For example, we may not have a transaction index or
> > producer
> > > > > > snapshot
> > > > > > > > > > for a
> > > > > > > > > > > particular segment. The former is optional, and the
> > latter is
> > > > > > only kept
> > > > > > > > > > for
> > > > > > > > > > > up to the 3 latest segments.
> > > > > > > > > > >
> > > > > > > > > > > This is a good point,  we discussed this in the last
> > meeting.
> > > > > > > > > > > Transaction index is optional and we will copy them only
> > if
> > > > it
> > > > > > exists.
> > > > > > > > > > > We want to keep all the producer snapshots at each log
> > > > segment
> > > > > > rolling
> > > > > > > > > > > and they can be removed if the log copying is successful
> > and
> > > > it
> > > > > > still
> > > > > > > > > > > maintains the existing latest 3 segments, We only delete
> > the
> > > > > > producer
> > > > > > > > > > > snapshots which have been copied to remote log segments
> > on
> > > > > > leader.
> > > > > > > > > > > Follower will keep the log segments beyond the segments
> > which
> > > > > > have not
> > > > > > > > > > > been copied to remote storage. We will update the KIP
> > with
> > > > these
> > > > > > > > > > > details.
> > > > > > > > > > >
> > > > > > > > > > > Thanks,
> > > > > > > > > > > Satish.
> > > > > > > > > > >
> > > > > > > > > > > On Thu, Sep 17, 2020 at 1:47 AM Dhruvil Shah <
> > > > > > dhruvil@confluent.io>
> > > > > > > > > > wrote:
> > > > > > > > > > > >
> > > > > > > > > > > > Hi Satish, Harsha,
> > > > > > > > > > > >
> > > > > > > > > > > > Thanks for the KIP. Few questions below:
> > > > > > > > > > > >
> > > > > > > > > > > > 1. Could you describe how retention would work with
> > this
> > > > KIP
> > > > > > and
> > > > > > > > > which
> > > > > > > > > > > > threads are responsible for driving this work? I
> > believe
> > > > there
> > > > > > are 3
> > > > > > > > > > kinds
> > > > > > > > > > > > of retention processes we are looking at:
> > > > > > > > > > > >   (a) Regular retention for data in tiered storage as
> > per
> > > > > > configured
> > > > > > > > > `
> > > > > > > > > > > > retention.ms` / `retention.bytes`.
> > > > > > > > > > > >   (b) Local retention for data in local storage as per
> > > > > > configured `
> > > > > > > > > > > > local.log.retention.ms` / `local.log.retention.bytes`
> > > > > > > > > > > >   (c) Possibly regular retention for data in local
> > > > storage, if
> > > > > > the
> > > > > > > > > > tiering
> > > > > > > > > > > > task is lagging or for data that is below the log start
> > > > offset.
> > > > > > > > > > > >
> > > > > > > > > > > > 2. When does a segment become eligible to be tiered?
> > Is it
> > > > as
> > > > > > soon as
> > > > > > > > > > the
> > > > > > > > > > > > segment is rolled and the end offset is less than the
> > last
> > > > > > stable
> > > > > > > > > > offset as
> > > > > > > > > > > > mentioned in the KIP? I wonder if we need to consider
> > other
> > > > > > > > > parameters
> > > > > > > > > > too,
> > > > > > > > > > > > like the highwatermark so that we are guaranteed that
> > what
> > > > we
> > > > > > are
> > > > > > > > > > tiering
> > > > > > > > > > > > has been committed to the log and accepted by the ISR.
> > > > > > > > > > > >
> > > > > > > > > > > > 3. The section on "Follower Fetch Scenarios" is useful
> > but
> > > > is
> > > > > > a bit
> > > > > > > > > > > > difficult to parse at the moment. It would be useful to
> > > > > > summarize the
> > > > > > > > > > > > changes we need in the ReplicaFetcher.
> > > > > > > > > > > >
> > > > > > > > > > > > 4. Related to the above, it's a bit unclear how we are
> > > > > > planning on
> > > > > > > > > > > > restoring the producer state for a new replica. Could
> > you
> > > > > > expand on
> > > > > > > > > > that?
> > > > > > > > > > > >
> > > > > > > > > > > > 5. Similarly, it would be worth summarizing the
> > behavior on
> > > > > > unclean
> > > > > > > > > > leader
> > > > > > > > > > > > election. There are several scenarios to consider here:
> > > > data
> > > > > > loss
> > > > > > > > > from
> > > > > > > > > > > > local log, data loss from remote log, data loss from
> > > > metadata
> > > > > > topic,
> > > > > > > > > > etc.
> > > > > > > > > > > > It's worth describing these in detail.
> > > > > > > > > > > >
> > > > > > > > > > > > 6. It would be useful to add details about how we plan
> > on
> > > > using
> > > > > > > > > > RocksDB in
> > > > > > > > > > > > the default implementation of
> > `RemoteLogMetadataManager`.
> > > > > > > > > > > >
> > > > > > > > > > > > 7. For a READ_COMMITTED FetchRequest, how do we
> > retrieve
> > > > and
> > > > > > return
> > > > > > > > > the
> > > > > > > > > > > > aborted transaction metadata?
> > > > > > > > > > > >
> > > > > > > > > > > > 8. The `LogSegmentData` class assumes that we have a
> > log
> > > > > > segment,
> > > > > > > > > > offset
> > > > > > > > > > > > index, time index, transaction index, producer
> > snapshot and
> > > > > > leader
> > > > > > > > > > epoch
> > > > > > > > > > > > index. How do we deal with cases where we do not have
> > one
> > > > or
> > > > > > more of
> > > > > > > > > > these?
> > > > > > > > > > > > For example, we may not have a transaction index or
> > > > producer
> > > > > > snapshot
> > > > > > > > > > for a
> > > > > > > > > > > > particular segment. The former is optional, and the
> > latter
> > > > is
> > > > > > only
> > > > > > > > > > kept for
> > > > > > > > > > > > up to the 3 latest segments.
> > > > > > > > > > > >
> > > > > > > > > > > > Thanks,
> > > > > > > > > > > > Dhruvil
> > > > > > > > > > > >
> > > > > > > > > > > > On Mon, Sep 7, 2020 at 6:54 PM Harsha Ch <
> > > > harsha.ch@gmail.com>
> > > > > > > > > wrote:
> > > > > > > > > > > >
> > > > > > > > > > > > > Hi All,
> > > > > > > > > > > > >
> > > > > > > > > > > > > We are all working through the last meeting feedback.
> > > > I'll
> > > > > > cancel
> > > > > > > > > the
> > > > > > > > > > > > > tomorrow 's meeting and we can meanwhile continue our
> > > > > > discussion in
> > > > > > > > > > mailing
> > > > > > > > > > > > > list. We can start the regular meeting from next week
> > > > > > onwards.
> > > > > > > > > > > > >
> > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > >
> > > > > > > > > > > > > Harsha
> > > > > > > > > > > > >
> > > > > > > > > > > > > On Fri, Sep 04, 2020 at 8:41 AM, Satish Duggana <
> > > > > > > > > > satish.duggana@gmail.com
> > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Hi Jun,
> > > > > > > > > > > > > > Thanks for your thorough review and comments.
> > Please
> > > > find
> > > > > > the
> > > > > > > > > > inline
> > > > > > > > > > > > > > replies below.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 600. The topic deletion logic needs more details.
> > > > > > > > > > > > > > 600.1 The KIP mentions "The controller considers
> > the
> > > > topic
> > > > > > > > > > partition is
> > > > > > > > > > > > > > deleted only when it determines that there are no
> > log
> > > > > > segments
> > > > > > > > > for
> > > > > > > > > > that
> > > > > > > > > > > > > > topic partition by using RLMM". How is this done?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > It uses RLMM#listSegments() returns all the
> > segments
> > > > for
> > > > > > the
> > > > > > > > > given
> > > > > > > > > > topic
> > > > > > > > > > > > > > partition.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 600.2 "If the delete option is enabled then the
> > leader
> > > > > > will stop
> > > > > > > > > > RLM task
> > > > > > > > > > > > > > and stop processing and it sets all the remote log
> > > > segment
> > > > > > > > > > metadata of
> > > > > > > > > > > > > > that partition with a delete marker and publishes
> > them
> > > > to
> > > > > > RLMM."
> > > > > > > > > We
> > > > > > > > > > > > > > discussed this earlier. When a topic is being
> > deleted,
> > > > > > there may
> > > > > > > > > > not be a
> > > > > > > > > > > > > > leader for the deleted partition.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > This is a good point. As suggested in the meeting,
> > we
> > > > will
> > > > > > add a
> > > > > > > > > > separate
> > > > > > > > > > > > > > section for topic/partition deletion lifecycle and
> > this
> > > > > > scenario
> > > > > > > > > > will be
> > > > > > > > > > > > > > addressed.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 601. Unclean leader election
> > > > > > > > > > > > > > 601.1 Scenario 1: new empty follower
> > > > > > > > > > > > > > After step 1, the follower restores up to offset
> > 3. So
> > > > why
> > > > > > does
> > > > > > > > > it
> > > > > > > > > > have
> > > > > > > > > > > > > > LE-2 <https://issues.apache.org/jira/browse/LE-2>
> > at
> > > > > > offset 5?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Nice catch. It was showing the leader epoch fetched
> > > > from
> > > > > > the
> > > > > > > > > remote
> > > > > > > > > > > > > > storage. It should be shown with the truncated till
> > > > offset
> > > > > > 3.
> > > > > > > > > > Updated the
> > > > > > > > > > > > > > KIP.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 601.2 senario 5: After Step 3, leader A has
> > > > inconsistent
> > > > > > data
> > > > > > > > > > between its
> > > > > > > > > > > > > > local and the tiered data. For example. offset 3
> > has
> > > > msg 3
> > > > > > LE-0
> > > > > > > > > > <https://issues.apache.org/jira/browse/LE-0> locally,
> > > > > > > > > > > > > > but msg 5 LE-1 <
> > > > https://issues.apache.org/jira/browse/LE-1>
> > > > > > in
> > > > > > > > > > the remote store. While it's ok for the unclean leader
> > > > > > > > > > > > > > to lose data, it should still return consistent
> > data,
> > > > > > whether
> > > > > > > > > it's
> > > > > > > > > > from
> > > > > > > > > > > > > > the local or the remote store.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > There is no inconsistency here as LE-0
> > > > > > > > > > <https://issues.apache.org/jira/browse/LE-0> offsets are
> > [0,
> > > > 4]
> > > > > > and LE-2
> > > > > > > > > > <https://issues.apache.org/jira/browse/LE-2>:
> > > > > > > > > > > > > > [5, ]. It will always get the right records for the
> > > > given
> > > > > > offset
> > > > > > > > > > and
> > > > > > > > > > > > > > leader epoch. In case of remote, RSM is invoked to
> > get
> > > > the
> > > > > > remote
> > > > > > > > > > log
> > > > > > > > > > > > > > segment that contains the given offset with the
> > leader
> > > > > > epoch.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 601.4 It seems that retention is based on
> > > > > > > > > > > > > > listRemoteLogSegments(TopicPartition
> > topicPartition,
> > > > long
> > > > > > > > > > leaderEpoch).
> > > > > > > > > > > > > > When there is an unclean leader election, it's
> > possible
> > > > > > for the
> > > > > > > > > new
> > > > > > > > > > > > > leader
> > > > > > > > > > > > > > to not to include certain epochs in its epoch
> > cache.
> > > > How
> > > > > > are
> > > > > > > > > remote
> > > > > > > > > > > > > > segments associated with those epochs being
> > cleaned?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > That is a good point. This leader will also
> > cleanup the
> > > > > > epochs
> > > > > > > > > > earlier to
> > > > > > > > > > > > > > its start leader epoch and delete those segments.
> > It
> > > > gets
> > > > > > the
> > > > > > > > > > earliest
> > > > > > > > > > > > > > epoch for a partition and starts deleting segments
> > from
> > > > > > that
> > > > > > > > > leader
> > > > > > > > > > > > > epoch.
> > > > > > > > > > > > > > We need one more API in RLMM to get the earliest
> > leader
> > > > > > epoch.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 601.5 The KIP discusses the handling of unclean
> > leader
> > > > > > elections
> > > > > > > > > > for user
> > > > > > > > > > > > > > topics. What about unclean leader elections on
> > > > > > > > > > > > > > __remote_log_segment_metadata?
> > > > > > > > > > > > > > This is the same as other system topics like
> > > > > > consumer_offsets,
> > > > > > > > > > > > > > __transaction_state topics. As discussed in the
> > > > meeting,
> > > > > > we will
> > > > > > > > > > add the
> > > > > > > > > > > > > > behavior of __remote_log_segment_metadata topic’s
> > > > unclean
> > > > > > leader
> > > > > > > > > > > > > > truncation.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 602. It would be useful to clarify the limitations
> > in
> > > > the
> > > > > > initial
> > > > > > > > > > > > > release.
> > > > > > > > > > > > > > The KIP mentions not supporting compacted topics.
> > What
> > > > > > about JBOD
> > > > > > > > > > and
> > > > > > > > > > > > > > changing the configuration of a topic from delete
> > to
> > > > > > compact
> > > > > > > > > after
> > > > > > > > > > > > > remote.
> > > > > > > > > > > > > > log. storage. enable (
> > > > http://remote.log.storage.enable/
> > > > > > ) is
> > > > > > > > > > enabled?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > This was updated in the KIP earlier.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 603. RLM leader tasks:
> > > > > > > > > > > > > > 603.1"It checks for rolled over LogSegments (which
> > have
> > > > > > the last
> > > > > > > > > > message
> > > > > > > > > > > > > > offset less than last stable offset of that topic
> > > > > > partition) and
> > > > > > > > > > copies
> > > > > > > > > > > > > > them along with their offset/time/transaction
> > indexes
> > > > and
> > > > > > leader
> > > > > > > > > > epoch
> > > > > > > > > > > > > > cache to the remote tier." It needs to copy the
> > > > producer
> > > > > > snapshot
> > > > > > > > > > too.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Right. It copies producer snapshots too as
> > mentioned in
> > > > > > > > > > LogSegmentData.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 603.2 "Local logs are not cleaned up till those
> > > > segments
> > > > > > are
> > > > > > > > > copied
> > > > > > > > > > > > > > successfully to remote even though their retention
> > > > > > time/size is
> > > > > > > > > > reached"
> > > > > > > > > > > > > > This seems weird. If the tiering stops because the
> > > > remote
> > > > > > store
> > > > > > > > > is
> > > > > > > > > > not
> > > > > > > > > > > > > > available, we don't want the local data to grow
> > > > forever.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > It was clarified in the discussion that the
> > comment was
> > > > > > more
> > > > > > > > > about
> > > > > > > > > > the
> > > > > > > > > > > > > > local storage goes beyond the log.retention. The
> > above
> > > > > > statement
> > > > > > > > > > is about
> > > > > > > > > > > > > > local.log.retention but not for the complete
> > > > > > log.retention. When
> > > > > > > > > it
> > > > > > > > > > > > > > reaches the log.retention then it will delete the
> > local
> > > > > > logs even
> > > > > > > > > > though
> > > > > > > > > > > > > > those are not copied to remote storage.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 604. "RLM maintains a bounded cache(possibly LRU)
> > of
> > > > the
> > > > > > index
> > > > > > > > > > files of
> > > > > > > > > > > > > > remote log segments to avoid multiple index fetches
> > > > from
> > > > > > the
> > > > > > > > > remote
> > > > > > > > > > > > > > storage. These indexes can be used in the same way
> > as
> > > > local
> > > > > > > > > segment
> > > > > > > > > > > > > > indexes are used." Could you provide more details
> > on
> > > > this?
> > > > > > Are
> > > > > > > > > the
> > > > > > > > > > > > > indexes
> > > > > > > > > > > > > > cached in memory or on disk? If on disk, where are
> > they
> > > > > > stored?
> > > > > > > > > > Are the
> > > > > > > > > > > > > > cached indexes bound by a certain size?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > These are cached on disk and stored in log.dir
> > with a
> > > > name
> > > > > > > > > > > > > > “__remote_log_index_cache”. They are bound by the
> > total
> > > > > > size.
> > > > > > > > > This
> > > > > > > > > > will
> > > > > > > > > > > > > be
> > > > > > > > > > > > > > exposed as a user configuration,
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 605. BuildingRemoteLogAux
> > > > > > > > > > > > > > 605.1 In this section, two options are listed.
> > Which
> > > > one is
> > > > > > > > > chosen?
> > > > > > > > > > > > > > Option-2, updated the KIP.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 605.2 In option 2, it says "Build the local leader
> > > > epoch
> > > > > > cache by
> > > > > > > > > > cutting
> > > > > > > > > > > > > > the leader epoch sequence received from remote
> > storage
> > > > to
> > > > > > [LSO,
> > > > > > > > > > ELO].
> > > > > > > > > > > > > (LSO
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > = log start offset)." We need to do the same thing
> > for
> > > > the
> > > > > > > > > producer
> > > > > > > > > > > > > > snapshot. However, it's hard to cut the producer
> > > > snapshot
> > > > > > to an
> > > > > > > > > > earlier
> > > > > > > > > > > > > > offset. Another option is to simply take the
> > lastOffset
> > > > > > from the
> > > > > > > > > > remote
> > > > > > > > > > > > > > segment and use that as the starting fetch offset
> > in
> > > > the
> > > > > > > > > follower.
> > > > > > > > > > This
> > > > > > > > > > > > > > avoids the need for cutting.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Right, this was mentioned in the “transactional
> > > > support”
> > > > > > section
> > > > > > > > > > about
> > > > > > > > > > > > > > adding these details.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 606. ListOffsets: Since we need a version bump,
> > could
> > > > you
> > > > > > > > > document
> > > > > > > > > > it
> > > > > > > > > > > > > > under a protocol change section?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Sure, we will update the KIP.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 607. "LogStartOffset of a topic can point to
> > either of
> > > > > > local
> > > > > > > > > > segment or
> > > > > > > > > > > > > > remote segment but it is initialised and
> > maintained in
> > > > the
> > > > > > Log
> > > > > > > > > > class like
> > > > > > > > > > > > > > now. This is already maintained in `Log` class
> > while
> > > > > > loading the
> > > > > > > > > > logs and
> > > > > > > > > > > > > > it can also be fetched from
> > RemoteLogMetadataManager."
> > > > > > What will
> > > > > > > > > > happen
> > > > > > > > > > > > > to
> > > > > > > > > > > > > > the existing logic (e.g. log recovery) that
> > currently
> > > > > > depends on
> > > > > > > > > > > > > > logStartOffset but assumes it's local?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > They use a field called localLogStartOffset which
> > is
> > > > the
> > > > > > local
> > > > > > > > > log
> > > > > > > > > > start
> > > > > > > > > > > > > > offset..
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 608. Handle expired remote segment: How does it
> > pick
> > > > up new
> > > > > > > > > > > > > logStartOffset
> > > > > > > > > > > > > > from deleteRecords?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Good point. This was not addressed in the KIP. Will
> > > > update
> > > > > > the
> > > > > > > > > KIP
> > > > > > > > > > on how
> > > > > > > > > > > > > > the RLM task handles this scenario.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 609. RLMM message format:
> > > > > > > > > > > > > > 609.1 It includes both MaxTimestamp and
> > EventTimestamp.
> > > > > > Where
> > > > > > > > > does
> > > > > > > > > > it get
> > > > > > > > > > > > > > both since the message in the log only contains one
> > > > > > timestamp?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > `EventTimeStamp` is the timestamp at which that
> > segment
> > > > > > metadata
> > > > > > > > > > event is
> > > > > > > > > > > > > > generated. This is more for audits.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 609.2 If we change just the state (e.g. to
> > > > > > DELETE_STARTED), it
> > > > > > > > > > seems it's
> > > > > > > > > > > > > > wasteful to have to include all other fields not
> > > > changed.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > This is a good point. We thought about incremental
> > > > > > updates. But
> > > > > > > > > we
> > > > > > > > > > want
> > > > > > > > > > > > > to
> > > > > > > > > > > > > > make sure all the events are in the expected order
> > and
> > > > take
> > > > > > > > > action
> > > > > > > > > > based
> > > > > > > > > > > > > > on the latest event. Will think through the
> > approaches
> > > > in
> > > > > > detail
> > > > > > > > > > and
> > > > > > > > > > > > > > update here.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 609.3 Could you document which process makes the
> > > > following
> > > > > > > > > > transitions
> > > > > > > > > > > > > > DELETE_MARKED, DELETE_STARTED, DELETE_FINISHED?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Okay, will document more details.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 610. remote.log.reader.max.pending.tasks: "Maximum
> > > > remote
> > > > > > log
> > > > > > > > > > reader
> > > > > > > > > > > > > > thread pool task queue size. If the task queue is
> > full,
> > > > > > broker
> > > > > > > > > > will stop
> > > > > > > > > > > > > > reading remote log segments." What does the broker
> > do
> > > > if
> > > > > > the
> > > > > > > > > queue
> > > > > > > > > > is
> > > > > > > > > > > > > > full?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > It returns an error for this topic partition.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 611. What do we return if the request offset/epoch
> > > > doesn't
> > > > > > exist
> > > > > > > > > > in the
> > > > > > > > > > > > > > following API?
> > > > > > > > > > > > > > RemoteLogSegmentMetadata
> > > > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > > > > > > topicPartition, long offset, int epochForOffset)
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > This returns null. But we prefer to update the
> > return
> > > > type
> > > > > > as
> > > > > > > > > > Optional
> > > > > > > > > > > > > and
> > > > > > > > > > > > > > return Empty if that does not exist.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > Satish.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > On Tue, Sep 1, 2020 at 9:45 AM Jun Rao < jun@
> > > > confluent.
> > > > > > io (
> > > > > > > > > > > > > > jun@confluent.io ) > wrote:
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >> Hi, Satish,
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >> Thanks for the updated KIP. Made another pass. A
> > few
> > > > more
> > > > > > > > > comments
> > > > > > > > > > > > > below.
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >> 600. The topic deletion logic needs more details.
> > > > > > > > > > > > > >> 600.1 The KIP mentions "The controller considers
> > the
> > > > topic
> > > > > > > > > > partition is
> > > > > > > > > > > > > >> deleted only when it determines that there are no
> > log
> > > > > > segments
> > > > > > > > > > for that
> > > > > > > > > > > > > >> topic partition by using RLMM". How is this done?
> > > > 600.2
> > > > > > "If the
> > > > > > > > > > delete
> > > > > > > > > > > > > >> option is enabled then the leader will stop RLM
> > task
> > > > and
> > > > > > stop
> > > > > > > > > > processing
> > > > > > > > > > > > > >> and it sets all the remote log segment metadata of
> > > > that
> > > > > > > > > partition
> > > > > > > > > > with a
> > > > > > > > > > > > > >> delete marker and publishes them to RLMM." We
> > > > discussed
> > > > > > this
> > > > > > > > > > earlier.
> > > > > > > > > > > > > When
> > > > > > > > > > > > > >> a topic is being deleted, there may not be a
> > leader
> > > > for
> > > > > > the
> > > > > > > > > > deleted
> > > > > > > > > > > > > >> partition.
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >> 601. Unclean leader election
> > > > > > > > > > > > > >> 601.1 Scenario 1: new empty follower
> > > > > > > > > > > > > >> After step 1, the follower restores up to offset
> > 3. So
> > > > > > why does
> > > > > > > > > > it have
> > > > > > > > > > > > > >> LE-2 <https://issues.apache.org/jira/browse/LE-2>
> > at
> > > > > > offset 5?
> > > > > > > > > > > > > >> 601.2 senario 5: After Step 3, leader A has
> > > > inconsistent
> > > > > > data
> > > > > > > > > > between
> > > > > > > > > > > > > its
> > > > > > > > > > > > > >> local and the tiered data. For example. offset 3
> > has
> > > > msg
> > > > > > 3 LE-0
> > > > > > > > > > <https://issues.apache.org/jira/browse/LE-0> locally,
> > > > > > > > > > > > > >> but msg 5 LE-1 <
> > > > > > https://issues.apache.org/jira/browse/LE-1> in
> > > > > > > > > > the remote store. While it's ok for the unclean leader
> > > > > > > > > > > > > >> to lose data, it should still return consistent
> > data,
> > > > > > whether
> > > > > > > > > > it's from
> > > > > > > > > > > > > >> the local or the remote store.
> > > > > > > > > > > > > >> 601.3 The follower picks up log start offset
> > using the
> > > > > > following
> > > > > > > > > > api.
> > > > > > > > > > > > > >> Suppose that we have 3 remote segments (LE,
> > > > > > SegmentStartOffset)
> > > > > > > > > > as (2,
> > > > > > > > > > > > > >> 10),
> > > > > > > > > > > > > >> (3, 20) and (7, 15) due to an unclean leader
> > election.
> > > > > > Using the
> > > > > > > > > > > > > following
> > > > > > > > > > > > > >> api will cause logStartOffset to go backward from
> > 20
> > > > to
> > > > > > 15. How
> > > > > > > > > > do we
> > > > > > > > > > > > > >> prevent that?
> > > > > > > > > > > > > >> earliestLogOffset(TopicPartition topicPartition,
> > int
> > > > > > > > > leaderEpoch)
> > > > > > > > > > 601.4
> > > > > > > > > > > > > It
> > > > > > > > > > > > > >> seems that retention is based on
> > > > > > > > > > > > > >> listRemoteLogSegments(TopicPartition
> > topicPartition,
> > > > long
> > > > > > > > > > leaderEpoch).
> > > > > > > > > > > > > >> When there is an unclean leader election, it's
> > > > possible
> > > > > > for the
> > > > > > > > > > new
> > > > > > > > > > > > > leader
> > > > > > > > > > > > > >> to not to include certain epochs in its epoch
> > cache.
> > > > How
> > > > > > are
> > > > > > > > > > remote
> > > > > > > > > > > > > >> segments associated with those epochs being
> > cleaned?
> > > > > > 601.5 The
> > > > > > > > > KIP
> > > > > > > > > > > > > >> discusses the handling of unclean leader
> > elections for
> > > > > > user
> > > > > > > > > > topics. What
> > > > > > > > > > > > > >> about unclean leader elections on
> > > > > > > > > > > > > >> __remote_log_segment_metadata?
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >> 602. It would be useful to clarify the
> > limitations in
> > > > the
> > > > > > > > > initial
> > > > > > > > > > > > > release.
> > > > > > > > > > > > > >> The KIP mentions not supporting compacted topics.
> > What
> > > > > > about
> > > > > > > > > JBOD
> > > > > > > > > > and
> > > > > > > > > > > > > >> changing the configuration of a topic from delete
> > to
> > > > > > compact
> > > > > > > > > after
> > > > > > > > > > > > > remote.
> > > > > > > > > > > > > >> log. storage. enable (
> > > > http://remote.log.storage.enable/
> > > > > > ) is
> > > > > > > > > > enabled?
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >> 603. RLM leader tasks:
> > > > > > > > > > > > > >> 603.1"It checks for rolled over LogSegments (which
> > > > have
> > > > > > the last
> > > > > > > > > > message
> > > > > > > > > > > > > >> offset less than last stable offset of that topic
> > > > > > partition) and
> > > > > > > > > > copies
> > > > > > > > > > > > > >> them along with their offset/time/transaction
> > indexes
> > > > and
> > > > > > leader
> > > > > > > > > > epoch
> > > > > > > > > > > > > >> cache to the remote tier." It needs to copy the
> > > > producer
> > > > > > > > > snapshot
> > > > > > > > > > too.
> > > > > > > > > > > > > >> 603.2 "Local logs are not cleaned up till those
> > > > segments
> > > > > > are
> > > > > > > > > > copied
> > > > > > > > > > > > > >> successfully to remote even though their retention
> > > > > > time/size is
> > > > > > > > > > reached"
> > > > > > > > > > > > > >> This seems weird. If the tiering stops because the
> > > > remote
> > > > > > store
> > > > > > > > > > is not
> > > > > > > > > > > > > >> available, we don't want the local data to grow
> > > > forever.
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >> 604. "RLM maintains a bounded cache(possibly LRU)
> > of
> > > > the
> > > > > > index
> > > > > > > > > > files of
> > > > > > > > > > > > > >> remote log segments to avoid multiple index
> > fetches
> > > > from
> > > > > > the
> > > > > > > > > > remote
> > > > > > > > > > > > > >> storage. These indexes can be used in the same
> > way as
> > > > > > local
> > > > > > > > > > segment
> > > > > > > > > > > > > >> indexes are used." Could you provide more details
> > on
> > > > > > this? Are
> > > > > > > > > the
> > > > > > > > > > > > > indexes
> > > > > > > > > > > > > >> cached in memory or on disk? If on disk, where are
> > > > they
> > > > > > stored?
> > > > > > > > > > Are the
> > > > > > > > > > > > > >> cached indexes bound by a certain size?
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >> 605. BuildingRemoteLogAux
> > > > > > > > > > > > > >> 605.1 In this section, two options are listed.
> > Which
> > > > one
> > > > > > is
> > > > > > > > > > chosen?
> > > > > > > > > > > > > 605.2
> > > > > > > > > > > > > >> In option 2, it says "Build the local leader epoch
> > > > cache
> > > > > > by
> > > > > > > > > > cutting the
> > > > > > > > > > > > > >> leader epoch sequence received from remote
> > storage to
> > > > > > [LSO,
> > > > > > > > > ELO].
> > > > > > > > > > (LSO
> > > > > > > > > > > > > >> = log start offset)." We need to do the same thing
> > > > for the
> > > > > > > > > > producer
> > > > > > > > > > > > > >> snapshot. However, it's hard to cut the producer
> > > > snapshot
> > > > > > to an
> > > > > > > > > > earlier
> > > > > > > > > > > > > >> offset. Another option is to simply take the
> > > > lastOffset
> > > > > > from the
> > > > > > > > > > remote
> > > > > > > > > > > > > >> segment and use that as the starting fetch offset
> > in
> > > > the
> > > > > > > > > > follower. This
> > > > > > > > > > > > > >> avoids the need for cutting.
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >> 606. ListOffsets: Since we need a version bump,
> > could
> > > > you
> > > > > > > > > > document it
> > > > > > > > > > > > > >> under a protocol change section?
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >> 607. "LogStartOffset of a topic can point to
> > either of
> > > > > > local
> > > > > > > > > > segment or
> > > > > > > > > > > > > >> remote segment but it is initialised and
> > maintained in
> > > > > > the Log
> > > > > > > > > > class
> > > > > > > > > > > > > like
> > > > > > > > > > > > > >> now. This is already maintained in `Log` class
> > while
> > > > > > loading the
> > > > > > > > > > logs
> > > > > > > > > > > > > and
> > > > > > > > > > > > > >> it can also be fetched from
> > RemoteLogMetadataManager."
> > > > > > What will
> > > > > > > > > > happen
> > > > > > > > > > > > > to
> > > > > > > > > > > > > >> the existing logic (e.g. log recovery) that
> > currently
> > > > > > depends on
> > > > > > > > > > > > > >> logStartOffset but assumes it's local?
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >> 608. Handle expired remote segment: How does it
> > pick
> > > > up
> > > > > > new
> > > > > > > > > > > > > logStartOffset
> > > > > > > > > > > > > >> from deleteRecords?
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >> 609. RLMM message format:
> > > > > > > > > > > > > >> 609.1 It includes both MaxTimestamp and
> > > > EventTimestamp.
> > > > > > Where
> > > > > > > > > > does it
> > > > > > > > > > > > > get
> > > > > > > > > > > > > >> both since the message in the log only contains
> > one
> > > > > > timestamp?
> > > > > > > > > > 609.2 If
> > > > > > > > > > > > > we
> > > > > > > > > > > > > >> change just the state (e.g. to DELETE_STARTED), it
> > > > seems
> > > > > > it's
> > > > > > > > > > wasteful
> > > > > > > > > > > > > to
> > > > > > > > > > > > > >> have to include all other fields not changed.
> > 609.3
> > > > Could
> > > > > > you
> > > > > > > > > > document
> > > > > > > > > > > > > >> which process makes the following transitions
> > > > > > DELETE_MARKED,
> > > > > > > > > > > > > >> DELETE_STARTED, DELETE_FINISHED?
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >> 610. remote.log.reader.max.pending.tasks: "Maximum
> > > > remote
> > > > > > log
> > > > > > > > > > reader
> > > > > > > > > > > > > >> thread pool task queue size. If the task queue is
> > > > full,
> > > > > > broker
> > > > > > > > > > will stop
> > > > > > > > > > > > > >> reading remote log segments." What does the
> > broker do
> > > > if
> > > > > > the
> > > > > > > > > > queue is
> > > > > > > > > > > > > >> full?
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >> 611. What do we return if the request offset/epoch
> > > > > > doesn't exist
> > > > > > > > > > in the
> > > > > > > > > > > > > >> following API?
> > > > > > > > > > > > > >> RemoteLogSegmentMetadata
> > > > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > > > > > >> topicPartition, long offset, int epochForOffset)
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >> Jun
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >> On Mon, Aug 31, 2020 at 11:19 AM Satish Duggana <
> > > > satish.
> > > > > > > > > duggana@
> > > > > > > > > > > > > gmail. com
> > > > > > > > > > > > > >> ( satish.duggana@gmail.com ) > wrote:
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>> KIP is updated with
> > > > > > > > > > > > > >>> - Remote log segment metadata topic message
> > > > > > format/schema.
> > > > > > > > > > > > > >>> - Added remote log segment metadata state
> > > > transitions and
> > > > > > > > > > explained how
> > > > > > > > > > > > > >>> the deletion of segments is handled, including
> > the
> > > > case
> > > > > > of
> > > > > > > > > > partition
> > > > > > > > > > > > > >>> deletions.
> > > > > > > > > > > > > >>> - Added a few more limitations in the "Non goals"
> > > > > > section.
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>> Thanks,
> > > > > > > > > > > > > >>> Satish.
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>> On Thu, Aug 27, 2020 at 12:42 AM Harsha Ch <
> > harsha.
> > > > ch@
> > > > > > > > > gmail.
> > > > > > > > > > com (
> > > > > > > > > > > > > >>> harsha.ch@gmail.com ) > wrote:
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>> Updated the KIP with Meeting Notes section
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>> https:/ / cwiki. apache. org/ confluence/
> > display/
> > > > KAFKA/
> > > > > > > > > > > > > KIP-405 <
> > https://issues.apache.org/jira/browse/KIP-405>
> > > > > > > > > >
> > %3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> > > > > > > > > > > > > >>> (
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > >
> > > >
> > https://cwiki.apache.org/confluence/display/KAFKA/KIP-405%3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> > > > > > > > > > > > > >>> )
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>> On Tue, Aug 25, 2020 at 1:03 PM Jun Rao < jun@
> > > > > > confluent. io
> > > > > > > > > (
> > > > > > > > > > > > > >>>> jun@confluent.io ) > wrote:
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>> Hi, Harsha,
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>> Thanks for the summary. Could you add the
> > summary
> > > > and
> > > > > > the
> > > > > > > > > > recording
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>> link to
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>> the last section of
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>> https:/ / cwiki. apache. org/ confluence/
> > display/
> > > > KAFKA/
> > > > > > > > > > > > > Kafka+Improvement+Proposals
> > > > > > > > > > > > > >>> (
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > >
> > > >
> > https://cwiki.apache.org/confluence/display/KAFKA/Kafka+Improvement+Proposals
> > > > > > > > > > > > > >>> )
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>> ?
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>> Jun
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>> On Tue, Aug 25, 2020 at 11:12 AM Harsha
> > > > Chintalapani <
> > > > > > kafka@
> > > > > > > > > > > > > harsha. io (
> > > > > > > > > > > > > >>>>> kafka@harsha.io ) > wrote:
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>> Thanks everyone for attending the meeting
> > today.
> > > > > > > > > > > > > >>>>>> Here is the recording
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>> https:/ / drive. google. com/ file/ d/
> > > > > > > > > > > > > 14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/ view?usp=sharing
> > > > > > > > > > > > > >>> (
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > >
> > > >
> > https://drive.google.com/file/d/14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/view?usp=sharing
> > > > > > > > > > > > > >>> )
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>> Notes:
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>> 1. KIP is updated with follower fetch
> > protocol and
> > > > > > ready to
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>> reviewed
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>> 2. Satish to capture schema of internal
> > metadata
> > > > > > topic in
> > > > > > > > > the
> > > > > > > > > > KIP
> > > > > > > > > > > > > >>>>>> 3. We will update the KIP with details of
> > > > different
> > > > > > cases
> > > > > > > > > > > > > >>>>>> 4. Test plan will be captured in a doc and
> > will
> > > > add
> > > > > > to the
> > > > > > > > > KIP
> > > > > > > > > > > > > >>>>>> 5. Add a section "Limitations" to capture the
> > > > > > capabilities
> > > > > > > > > > that
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>> will
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>> be
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>> introduced with this KIP and what will not be
> > > > covered
> > > > > > in
> > > > > > > > > this
> > > > > > > > > > KIP.
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>> Please add to it I missed anything. Will
> > produce a
> > > > > > formal
> > > > > > > > > > meeting
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>> notes
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>> from next meeting onwards.
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>> Thanks,
> > > > > > > > > > > > > >>>>>> Harsha
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>> On Mon, Aug 24, 2020 at 9:42 PM, Ying Zheng <
> > > > yingz@
> > > > > > uber.
> > > > > > > > > > com.
> > > > > > > > > > > > > invalid (
> > > > > > > > > > > > > >>>>>> yingz@uber.com.invalid ) > wrote:
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> We did some basic feature tests at Uber. The
> > test
> > > > > > cases and
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>> results are
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> shared in this google doc:
> > > > > > > > > > > > > >>>>>>> https:/ / docs. google. com/ spreadsheets/
> > d/ (
> > > > > > > > > > > > > >>>>>>> https://docs.google.com/spreadsheets/d/ )
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > 1XhNJqjzwXvMCcAOhEH0sSXU6RTvyoSf93DHF-YMfGLk/edit?usp=sharing
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> The performance test results were already
> > shared
> > > > in
> > > > > > the KIP
> > > > > > > > > > last
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>> month.
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> On Mon, Aug 24, 2020 at 11:10 AM Harsha Ch <
> > > > harsha.
> > > > > > ch@
> > > > > > > > > > gmail.
> > > > > > > > > > > > > com (
> > > > > > > > > > > > > >>>>>>> harsha.ch@gmail.com ) >
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>> wrote:
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> "Understand commitments towards driving
> > design &
> > > > > > > > > > implementation of
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>> the
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>> KIP
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> further and how it aligns with participant
> > > > interests
> > > > > > in
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>> contributing to
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>> the
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> efforts (ex: in the context of Uber’s Q3/Q4
> > > > > > roadmap)." What
> > > > > > > > > > is that
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>> about?
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> On Mon, Aug 24, 2020 at 11:05 AM Kowshik
> > > > Prakasam <
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>> kprakasam@ confluent. io (
> > kprakasam@confluent.io
> > > > ) >
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> wrote:
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> Hi Harsha,
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> The following google doc contains a proposal
> > for
> > > > > > temporary
> > > > > > > > > > agenda
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>> for
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>> the
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> KIP-405 <
> > > > > > https://issues.apache.org/jira/browse/KIP-405> <
> > > > > > > > > > https:/ / issues. apache. org/ jira/ browse/ KIP-405
> > > > > > > > > > <https://issues.apache.org/jira/browse/KIP-405> (
> > > > > > > > > > > > > >>>>>>>
> > https://issues.apache.org/jira/browse/KIP-405 )
> > > > >
> > > > > > sync
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>> meeting
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> tomorrow:
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> https:/ / docs. google. com/ document/ d/ (
> > > > > > > > > > > > > >>>>>>> https://docs.google.com/document/d/ )
> > > > > > > > > > > > > >>>>>>>
> > 1pqo8X5LU8TpwfC_iqSuVPezhfCfhGkbGN2TqiPA3LBU/edit
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> .
> > > > > > > > > > > > > >>>>>>> Please could you add it to the Google
> > calendar
> > > > > > invite?
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> Thank you.
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> Cheers,
> > > > > > > > > > > > > >>>>>>> Kowshik
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> On Thu, Aug 20, 2020 at 10:58 AM Harsha Ch <
> > > > harsha.
> > > > > > ch@
> > > > > > > > > > gmail.
> > > > > > > > > > > > > com (
> > > > > > > > > > > > > >>>>>>> harsha.ch@gmail.com ) >
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>> wrote:
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> Hi All,
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> Scheduled a meeting for Tuesday 9am - 10am.
> > I can
> > > > > > record
> > > > > > > > > and
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>> upload for
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> community to be able to follow the
> > discussion.
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> Jun, please add the required folks on
> > confluent
> > > > side.
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> Thanks,
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> Harsha
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> On Thu, Aug 20, 2020 at 12:33 AM, Alexandre
> > > > Dupriez <
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>> alexandre.dupriez@
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> gmail. com ( http://gmail.com/ ) > wrote:
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> Hi Jun,
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> Many thanks for your initiative.
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> If you like, I am happy to attend at the
> > time you
> > > > > > > > > suggested.
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> Many thanks,
> > > > > > > > > > > > > >>>>>>> Alexandre
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> Le mer. 19 août 2020 à 22:00, Harsha Ch <
> > > > harsha. ch@
> > > > > > > > > > gmail. com (
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>> harsha.
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> ch@ gmail. com ( ch@gmail.com ) ) > a écrit
> > :
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> Hi Jun,
> > > > > > > > > > > > > >>>>>>> Thanks. This will help a lot. Tuesday will
> > work
> > > > for
> > > > > > us.
> > > > > > > > > > > > > >>>>>>> -Harsha
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> On Wed, Aug 19, 2020 at 1:24 PM Jun Rao <
> > jun@
> > > > > > confluent.
> > > > > > > > > > io (
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>> jun@
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> confluent. io ( http://confluent.io/ ) ) >
> > > > wrote:
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> Hi, Satish, Ying, Harsha,
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> Do you think it would be useful to have a
> > regular
> > > > > > virtual
> > > > > > > > > > meeting
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>> to
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>
> > > > > > > > > > > > > >>>>
> > > > > > > > > > > > > >>>>>
> > > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> discuss this KIP? The goal of the meeting
> > will be
> > > > > > sharing
> > > > > > > > > > > > > >>>>>>> design/development progress and discussing
> > any
> > > > open
> > > > > > issues
> > > > > > > > > to
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> accelerate
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> this KIP. If so, will every Tuesday (from
> > next
> > > > week)
> > > > > > > > > 9am-10am
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> PT
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> work for you? I can help set up a Zoom
> > meeting,
> > > > > > invite
> > > > > > > > > > everyone who
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> might
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> be interested, have it recorded and shared,
> > etc.
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> Thanks,
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> Jun
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> On Tue, Aug 18, 2020 at 11:01 AM Satish
> > Duggana <
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> satish. duggana@ gmail. com ( satish.
> > duggana@
> > > > > > gmail. com
> > > > > > > > > (
> > > > > > > > > > > > > >>>>>>> satish.duggana@gmail.com ) ) >
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> wrote:
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> Hi Kowshik,
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> Thanks for looking into the KIP and sending
> > your
> > > > > > comments.
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > > >>>>>>> 5001. Under the section "Follower fetch
> > protocol
> > > > in
> > > > > > > > > detail",
> > > > > > > > > > the
> > > > > > > > > > > > > >>>>>>> next-local-offset is the offset upto which
> > the
> > > > > > segments are
> > > > > > > > > > copied
> > > > > > > > > > > > > >>>>>>>
> > > > > > > > > >
> > > > > >
> > > > > >
> > > >
> >

Re: [DISCUSS] KIP-405: Kafka Tiered Storage

[Kowshik Prakasam <kp...@confluent.io>]

Hi Satish,

Thanks for the updates! A few more comments below.

9001. Under the "Upgrade" section, there is a line mentioning: "Upgrade the
existing Kafka cluster to 2.7 version and allow this to run for the log
retention of user topics that you want to enable tiered storage. This will
allow all the topics to have the producer snapshots generated for each log
segment." -- Which associated change in AK were you referring to here? Is
it: https://github.com/apache/kafka/pull/7929 ? It seems like I don't see
it in the 2.7 release branch yet, here is the link:
https://github.com/apache/kafka/commits/2.7.

9002. Under the "Upgrade" section, the configuration mentioned is
'remote.log.storage.system.enable'. However, under "Public Interfaces"
section the corresponding configuration is 'remote.storage.system.enable'.
Could we use the same one in both, maybe 'remote.log.storage.system.enable'?

9003. Under "Per Topic Configuration", the KIP recommends setting
'remote.log.storage.enable' to true at a per-topic level. It will be useful
to add a line that if the user wants to enable it for all topics, then they
should be able to set the cluster-wide default to true. Also, it will be
useful to mention that the KIP currently does not support setting it to
false (after it is set to true), and add that to the future work section.

9004. Under "Committed offsets file format", the sample provided shows
partition number and offset. Is the topic name required for identifying
which topic the partitions belong to?

9005. Under "Internal flat-file store format of remote log metadata", it
seems useful to specify both topic name and topic ID for debugging
purposes.

9006. Under "Internal flat-file store format of remote log metadata", the
description of "metadata-topic-offset" currently says "offset of the remote
log metadata topic from which this topic partition's remote log metadata is
fetched." Just for the wording, perhaps you meant to refer to the offset
upto which the file has been committed? i.e. "offset of the remote log
metadata topic upto which this topic partition's remote log metadata has
been committed into this file."

9007. Under "Internal flat-file store format of remote log metadata", the
schema of the payload (i.e. beyond the header) seems to contain the events
from the metadata topic. It seems useful to instead persist the
representation of the materialized state of the events, so that for the
same segment only the latest state is stored. Besides reducing storage
footprint, this also is likely to relate directly with the in-memory
representation of the RLMM cache (which probably is some kind of a Map with
key being segment ID and value being the segment state), so recovery from
disk will be straightforward.

9008. Under "Topic deletion lifecycle", step (1), it will be useful to
mention when in the deletion flow does the controller publish the
delete_partition_marked event to say that the partition is marked for
deletion?

9009. There are ~4 TODOs in the KIP. Could you please address these or
remove them?

9010. There is a reference to a Google doc on the KIP which was used
earlier for discussions. Please could you remove the reference, since the
KIP is the source of the truth?

9011. This feedback is from an earlier comment. In the RemoteStorageManager
interface, there is an API defined for each file type. For example,
fetchOffsetIndex, fetchTimestampIndex etc. To avoid the duplication, I'd
suggest we can instead have a FileType enum and a common get API based on
the FileType. What do you think?


Cheers,
Kowshik


On Mon, Dec 14, 2020 at 11:07 AM Satish Duggana <sa...@gmail.com>
wrote:

> Hi Jun,
> Thanks for your comments. Please go through the inline replies.
>
>
> 5102.2: It seems that both positions can just be int. Another option is to
> have two methods. Would it be clearer?
>
>     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> remoteLogSegmentMetadata,  int startPosition) throwsRemoteStorageException;
>
>     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> remoteLogSegmentMetadata, int startPosition, int endPosition) throws
> RemoteStorageException;
>
> That makes sense to me, updated the KIP.
>
> 6003: Could you also update the javadoc for the return value?
>
> Updated.
>
> 6020: local.log.retention.bytes: Should it default to log.retention.bytes
> to be consistent with local.log.retention.ms?
>
> Yes, it can be defaulted to log.retention.bytes.
>
> 6021: Could you define TopicIdPartition?
>
> Added TopicIdPartition in the KIP.
>
> 6022: For all public facing classes, could you specify the package name?
>
> Updated.
>
>
> Thanks,
> Satish.
>
> On Tue, Dec 8, 2020 at 12:59 AM Jun Rao <ju...@confluent.io> wrote:
> >
> > Hi, Satish,
> >
> > Thanks for the reply. A few more comments below.
> >
> > 5102.2: It seems that both positions can just be int. Another option is
> to
> > have two methods. Would it be clearer?
> >
> >     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> > remoteLogSegmentMetadata,
> >                                     int startPosition) throws
> > RemoteStorageException;
> >
> >     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> > remoteLogSegmentMetadata,
> >                                     int startPosition, int endPosition)
> > throws RemoteStorageException;
> >
> > 6003: Could you also update the javadoc for the return value?
> >
> > 6010: What kind of tiering throughput have you seen with 5 threads?
> >
> > 6020: local.log.retention.bytes: Should it default to log.retention.bytes
> > to be consistent with local.log.retention.ms?
> >
> > 6021: Could you define TopicIdPartition?
> >
> > 6022: For all public facing classes, could you specify the package name?
> >
> > It seems that you already added the topicId support. Two other remaining
> > items are (a) the format of local tier metadata storage and (b) upgrade.
> >
> > Jun
> >
> > On Mon, Dec 7, 2020 at 8:56 AM Satish Duggana <sa...@gmail.com>
> > wrote:
> >
> > > Hi Jun,
> > > Thanks for your comments. Please find the inline replies below.
> > >
> > > >605.2 It's rare for the follower to need the remote data. So, the
> current
> > > approach is fine too. Could you document the process of rebuilding the
> > > producer state since we can't simply trim the producerState to an
> offset in
> > > the middle of a segment.
> > >
> > > Will clarify in the KIP.
> > >
> > > >5102.2 Would it be clearer to make startPosiont long and endPosition
> of
> > > Optional<Long>?
> > >
> > > We will have arg checks with respective validation. It is not a good
> > > practice to have arguments with optional as mentioned here.
> > > https://rules.sonarsource.com/java/RSPEC-3553
> > >
> > >
> > > >5102.5 LogSegmentData still has leaderEpochIndex as File instead of
> > > ByteBuffer.
> > >
> > > Updated.
> > >
> > > >5102.7 Could you define all public methods for LogSegmentData?
> > >
> > > Updated.
> > >
> > > >5103.5 Could you change the reference to rlm_process_interval_ms and
> > > rlm_retry_interval_ms to the new config names? Also, the retry interval
> > > config seems still missing. It would be useful to support exponential
> > > backoff with the retry interval config.
> > >
> > > Good point. We wanted the retry with truncated exponential backoff,
> > > updated the KIP.
> > >
> > > >5111. "RLM follower fetches the earliest offset for the earliest
> leader
> > > epoch by calling RLMM.earliestLogOffset(TopicPartition topicPartition,
> int
> > > leaderEpoch) and updates that as the log start offset." This text is
> still
> > > there. Also, could we remove earliestLogOffset() from RLMM?
> > >
> > > Updated.
> > >
> > > >5115. There are still references to "remote log cleaners".
> > >
> > > Updated.
> > >
> > > >6000. Since we are returning new error codes, we need to bump up the
> > > protocol version for Fetch request. Also, it will be useful to
> document all
> > > new error codes and whether they are retriable or not.
> > >
> > > Sure, we will add that in the KIP.
> > >
> > > >6001. public Map<Long, Long> segmentLeaderEpochs(): Currently,
> leaderEpoch
> > > is int32 instead of long.
> > >
> > > Updated.
> > >
> > > >6002. Is RemoteLogSegmentMetadata.markedForDeletion() needed given
> > > RemoteLogSegmentMetadata.state()?
> > >
> > > No, it is fixed.
> > >
> > > >6003. RemoteLogSegmentMetadata remoteLogSegmentMetadata(TopicPartition
> > > topicPartition, long offset, int epochForOffset): Should this return
> > > Optional<RemoteLogSegmentMetadata>?
> > >
> > > That makes sense, updated.
> > >
> > > >6005. RemoteLogState: It seems it's better to split it between
> > > DeletePartitionUpdate and RemoteLogSegmentMetadataUpdate since the
> states
> > > are never shared between the two use cases.
> > >
> > > Agree with that, updated.
> > >
> > > >6006. RLMM.onPartitionLeadershipChanges(): This may be ok. However,
> is it
> > > ture that other than the metadata topic, RLMM just needs to know
> whether
> > > there is a replica assigned to this broker and doesn't need to know
> whether
> > > the replica is the leader or the follower?
> > >
> > > That may be true. If the implementation does not need that, it can
> > > ignore the information in the callback.
> > >
> > > >6007: "Handle expired remote segments (leader and follower)": Why is
> this
> > > needed in both the leader and the follower?
> > >
> > > Updated.
> > >
> > > >6008.       "name": "SegmentSizeInBytes",
> > >                 "type": "int64",
> > > The segment size can just be int32.
> > >
> > > Updated.
> > >
> > > >6009. For the record format in the log, it seems that we need to add
> > > record
> > > type and record version before the serialized bytes. We can follow the
> > > convention used in
> > >
> > >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-631%3A+The+Quorum-based+Kafka+Controller#KIP631:TheQuorumbasedKafkaController-RecordFormats
> > >
> > > Yes, KIP already mentions that these are serialized before the payload
> > > as below. We will mention explicitly that these two are written before
> > > the data is written.
> > >
> > > RLMM instance on broker publishes the message to the topic with key as
> > > null and value with the below format.
> > >
> > > type      : unsigned var int, represents the value type. This value is
> > > 'apikey' as mentioned in the schema.
> > > version : unsigned var int, the 'version' number of the type as
> > > mentioned in the schema.
> > > data      : record payload in kafka protocol message format.
> > >
> > >
> > > >6010. remote.log.manager.thread.pool.size: The default value is 10.
> This
> > > might be too high when enabling the tiered feature for the first time.
> > > Since there are lots of segments that need to be tiered initially, a
> large
> > > number of threads could overwhelm the broker.
> > >
> > > Is the default value 5 reasonable?
> > >
> > > 6011. "The number of milli seconds to keep the local log segment
> before it
> > > gets deleted. If not set, the value in `log.retention.minutes` is
> used. If
> > > set to -1, no time limit is applied." We should use log.retention.ms
> > > instead of log.retention.minutes.
> > > Nice typo catch. Updated the KIP.
> > >
> > > Thanks,
> > > Satish.
> > >
> > > On Thu, Dec 3, 2020 at 8:03 AM Jun Rao <ju...@confluent.io> wrote:
> > > >
> > > > Hi, Satish,
> > > >
> > > > Thanks for the updated KIP. A few more comments below.
> > > >
> > > > 605.2 It's rare for the follower to need the remote data. So, the
> current
> > > > approach is fine too. Could you document the process of rebuilding
> the
> > > > producer state since we can't simply trim the producerState to an
> offset
> > > in
> > > > the middle of a segment.
> > > >
> > > > 5102.2 Would it be clearer to make startPosiont long and endPosition
> of
> > > > Optional<Long>?
> > > >
> > > > 5102.5 LogSegmentData still has leaderEpochIndex as File instead of
> > > > ByteBuffer.
> > > >
> > > > 5102.7 Could you define all public methods for LogSegmentData?
> > > >
> > > > 5103.5 Could you change the reference to rlm_process_interval_ms and
> > > > rlm_retry_interval_ms to the new config names? Also, the retry
> interval
> > > > config seems still missing. It would be useful to support exponential
> > > > backoff with the retry interval config.
> > > >
> > > > 5111. "RLM follower fetches the earliest offset for the earliest
> leader
> > > > epoch by calling RLMM.earliestLogOffset(TopicPartition
> topicPartition,
> > > int
> > > > leaderEpoch) and updates that as the log start offset." This text is
> > > still
> > > > there. Also, could we remove earliestLogOffset() from RLMM?
> > > >
> > > > 5115. There are still references to "remote log cleaners".
> > > >
> > > > 6000. Since we are returning new error codes, we need to bump up the
> > > > protocol version for Fetch request. Also, it will be useful to
> document
> > > all
> > > > new error codes and whether they are retriable or not.
> > > >
> > > > 6001. public Map<Long, Long> segmentLeaderEpochs(): Currently,
> > > leaderEpoch
> > > > is int32 instead of long.
> > > >
> > > > 6002. Is RemoteLogSegmentMetadata.markedForDeletion() needed given
> > > > RemoteLogSegmentMetadata.state()?
> > > >
> > > > 6003. RemoteLogSegmentMetadata
> remoteLogSegmentMetadata(TopicPartition
> > > > topicPartition, long offset, int epochForOffset): Should this return
> > > > Optional<RemoteLogSegmentMetadata>?
> > > >
> > > > 6004. DeletePartitionUpdate.epoch(): It would be useful to pick a
> more
> > > > indicative name so that people understand what epoch this is.
> > > >
> > > > 6005. RemoteLogState: It seems it's better to split it between
> > > > DeletePartitionUpdate and RemoteLogSegmentMetadataUpdate since the
> states
> > > > are never shared between the two use cases.
> > > >
> > > > 6006. RLMM.onPartitionLeadershipChanges(): This may be ok. However,
> is it
> > > > ture that other than the metadata topic, RLMM just needs to know
> whether
> > > > there is a replica assigned to this broker and doesn't need to know
> > > whether
> > > > the replica is the leader or the follower?
> > > >
> > > > 6007: "Handle expired remote segments (leader and follower)": Why is
> this
> > > > needed in both the leader and the follower?
> > > >
> > > > 6008.       "name": "SegmentSizeInBytes",
> > > >                 "type": "int64",
> > > > The segment size can just be int32.
> > > >
> > > > 6009. For the record format in the log, it seems that we need to add
> > > record
> > > > type and record version before the serialized bytes. We can follow
> the
> > > > convention used in
> > > >
> > >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-631%3A+The+Quorum-based+Kafka+Controller#KIP631:TheQuorumbasedKafkaController-RecordFormats
> > > > .
> > > >
> > > > 6010. remote.log.manager.thread.pool.size: The default value is 10.
> This
> > > > might be too high when enabling the tiered feature for the first
> time.
> > > > Since there are lots of segments that need to be tiered initially, a
> > > large
> > > > number of threads could overwhelm the broker.
> > > >
> > > > 6011. "The number of milli seconds to keep the local log segment
> before
> > > it
> > > > gets deleted. If not set, the value in `log.retention.minutes` is
> used.
> > > If
> > > > set to -1, no time limit is applied." We should use log.retention.ms
> > > > instead of log.retention.minutes.
> > > >
> > > > Jun
> > > >
> > > > On Tue, Dec 1, 2020 at 2:42 AM Satish Duggana <
> satish.duggana@gmail.com>
> > > > wrote:
> > > >
> > > > > Hi,
> > > > > We updated the KIP with the points mentioned in the earlier mail
> > > > > except for KIP-516 related changes. You can go through them and
> let us
> > > > > know if you have any comments. We will update the KIP with the
> > > > > remaining todo items and KIP-516 related changes by end of this
> > > > > week(5th Dec).
> > > > >
> > > > > Thanks,
> > > > > Satish.
> > > > >
> > > > > On Tue, Nov 10, 2020 at 8:26 PM Satish Duggana <
> > > satish.duggana@gmail.com>
> > > > > wrote:
> > > > > >
> > > > > > Hi Jun,
> > > > > > Thanks for your comments. Please find the inline replies below.
> > > > > >
> > > > > > 605.2 "Build the local leader epoch cache by cutting the leader
> epoch
> > > > > > sequence received from remote storage to [LSO, ELO]." I
> mentioned an
> > > > > issue
> > > > > > earlier. Suppose the leader's local start offset is 100. The
> follower
> > > > > finds
> > > > > > a remote segment covering offset range [80, 120). The
> producerState
> > > with
> > > > > > this remote segment is up to offset 120. To trim the
> producerState to
> > > > > > offset 100 requires more work since one needs to download the
> > > previous
> > > > > > producerState up to offset 80 and then replay the messages from
> 80 to
> > > > > 100.
> > > > > > It seems that it's simpler in this case for the follower just to
> > > take the
> > > > > > remote segment as it is and start fetching from offset 120.
> > > > > >
> > > > > > We chose that approach to avoid any edge cases here. It may be
> > > > > > possible that the remote log segment that is received may not
> have
> > > the
> > > > > > same leader epoch sequence from 100-120 as it contains on the
> > > > > > leader(this can happen due to unclean leader). It is safe to
> start
> > > > > > from what the leader returns here.Another way is to find the
> remote
> > > > > > log segment
> > > > > >
> > > > > > 5016. Just to echo what Kowshik was saying. It seems that
> > > > > > RLMM.onPartitionLeadershipChanges() is only called on the
> replicas
> > > for a
> > > > > > partition, not on the replicas for the
> __remote_log_segment_metadata
> > > > > > partition. It's not clear how the leader of
> > > __remote_log_segment_metadata
> > > > > > obtains the metadata for remote segments for deletion.
> > > > > >
> > > > > > RLMM will always receive the callback for the remote log metadata
> > > > > > topic partitions hosted on the local broker and these will be
> > > > > > subscribed. I will make this clear in the KIP.
> > > > > >
> > > > > > 5100. KIP-516 has been accepted and is being implemented now.
> Could
> > > you
> > > > > > update the KIP based on topicID?
> > > > > >
> > > > > > We mentioned KIP-516 and how it helps. We will update this KIP
> with
> > > > > > all the changes it brings with KIP-516.
> > > > > >
> > > > > > 5101. RLMM: It would be useful to clarify how the following two
> APIs
> > > are
> > > > > > used. According to the wiki, the former is used for topic
> deletion
> > > and
> > > > > the
> > > > > > latter is used for retention. It seems that retention should use
> the
> > > > > former
> > > > > > since remote segments without a matching epoch in the leader
> > > (potentially
> > > > > > due to unclean leader election) also need to be garbage
> collected.
> > > The
> > > > > > latter seems to be used for the new leader to determine the last
> > > tiered
> > > > > > segment.
> > > > > >     default Iterator<RemoteLogSegmentMetadata>
> > > > > > listRemoteLogSegments(TopicPartition topicPartition)
> > > > > >     Iterator<RemoteLogSegmentMetadata>
> > > > > listRemoteLogSegments(TopicPartition
> > > > > > topicPartition, long leaderEpoch);
> > > > > >
> > > > > > Right,.that is what we are currently doing. We will update the
> > > > > > javadocs and wiki with that. Earlier, we did not want to remove
> the
> > > > > > segments which are not matched with leader epochs from the ladder
> > > > > > partition as they may be used later by a replica which can
> become a
> > > > > > leader (unclean leader election) and refer those segments. But
> that
> > > > > > may leak these segments in remote storage until the topic
> lifetime.
> > > We
> > > > > > decided to cleanup the segments with the oldest incase of size
> based
> > > > > > retention also.
> > > > > >
> > > > > > 5102. RSM:
> > > > > > 5102.1 For methods like fetchLogSegmentData(), it seems that
> they can
> > > > > > use RemoteLogSegmentId instead of RemoteLogSegmentMetadata.
> > > > > >
> > > > > > It will be useful to have metadata for RSM to fetch log segment.
> It
> > > > > > may create location/path using id with other metadata too.
> > > > > >
> > > > > > 5102.2 In fetchLogSegmentData(), should we use long instead of
> Long?
> > > > > >
> > > > > > Wanted to keep endPosition as optional to read till the end of
> the
> > > > > > segment and avoid sentinels.
> > > > > >
> > > > > > 5102.3 Why only some of the methods have default implementation
> and
> > > > > others
> > > > > > Don't?
> > > > > >
> > > > > > Actually,  RSM will not have any default implementations. Those 3
> > > > > > methods were made default earlier for tests etc. Updated the
> wiki.
> > > > > >
> > > > > > 5102.4. Could we define RemoteLogSegmentMetadataUpdate
> > > > > > and DeletePartitionUpdate?
> > > > > >
> > > > > > Sure, they will be added.
> > > > > >
> > > > > >
> > > > > > 5102.5 LogSegmentData: It seems that it's easier to pass
> > > > > > in leaderEpochIndex as a ByteBuffer or byte array than a file
> since
> > > it
> > > > > will
> > > > > > be generated in memory.
> > > > > >
> > > > > > Right, this is in plan.
> > > > > >
> > > > > > 5102.6 RemoteLogSegmentMetadata: It seems that it needs both
> > > baseOffset
> > > > > and
> > > > > > startOffset. For example, deleteRecords() could move the
> startOffset
> > > to
> > > > > the
> > > > > > middle of a segment. If we copy the full segment to remote
> storage,
> > > the
> > > > > > baseOffset and the startOffset will be different.
> > > > > >
> > > > > > Good point. startOffset is baseOffset by default, if not set
> > > explicitly.
> > > > > >
> > > > > > 5102.7 Could we define all the public methods for
> > > > > RemoteLogSegmentMetadata
> > > > > > and LogSegmentData?
> > > > > >
> > > > > > Sure, updated the wiki.
> > > > > >
> > > > > > 5102.8 Could we document whether endOffset in
> > > RemoteLogSegmentMetadata is
> > > > > > inclusive/exclusive?
> > > > > >
> > > > > > It is inclusive, will update.
> > > > > >
> > > > > > 5103. configs:
> > > > > > 5103.1 Could we define the default value of non-required configs
> > > (e.g the
> > > > > > size of new thread pools)?
> > > > > >
> > > > > > Sure, that makes sense.
> > > > > >
> > > > > > 5103.2 It seems that local.log.retention.ms should default to
> > > > > retention.ms,
> > > > > > instead of remote.log.retention.minutes. Similarly, it seems
> > > > > > that local.log.retention.bytes should default to segment.bytes.
> > > > > >
> > > > > > Right, we do not have  remote.log.retention as we discussed
> earlier.
> > > > > > Thanks for catching the typo.
> > > > > >
> > > > > > 5103.3 remote.log.manager.thread.pool.size: The description says
> > > "used in
> > > > > > scheduling tasks to copy segments, fetch remote log indexes and
> > > clean up
> > > > > > remote log segments". However, there is a separate
> > > > > > config remote.log.reader.threads for fetching remote data. It's
> > > weird to
> > > > > > fetch remote index and log in different thread pools since both
> are
> > > used
> > > > > > for serving fetch requests.
> > > > > >
> > > > > > Right, remote.log.manager.thread.pool is mainly used for
> copy/cleanup
> > > > > > activities. Fetch path always goes through
> remote.log.reader.threads.
> > > > > >
> > > > > > 5103.4 remote.log.manager.task.interval.ms: Is that the amount
> of
> > > time
> > > > > to
> > > > > > back off when there is no work to do? If so, perhaps it can be
> > > renamed as
> > > > > > backoff.ms.
> > > > > >
> > > > > > This is the delay interval for each iteration. It may be renamed
> to
> > > > > > remote.log.manager.task.delay.ms
> > > > > >
> > > > > > 5103.5 Are rlm_process_interval_ms and rlm_retry_interval_ms
> > > configs? If
> > > > > > so, they need to be listed in this section.
> > > > > >
> > > > > > remote.log.manager.task.interval.ms is the process internal,
> retry
> > > > > > interval is missing in the configs, which will be updated in the
> KIP.
> > > > > >
> > > > > > 5104. "RLM maintains a bounded cache(possibly LRU) of the index
> > > files of
> > > > > > remote log segments to avoid multiple index fetches from the
> remote
> > > > > > storage." Is the RLM in memory or on disk? If on disk, where is
> it
> > > > > stored?
> > > > > > Do we need a configuration to bound the size?
> > > > > >
> > > > > > It is stored on disk. They are stored in a directory
> > > > > > `remote-log-index-cache` under log dir. We plan to have a config
> for
> > > > > > that instead of default. We will have a configuration for that.
> > > > > >
> > > > > > 5105. The KIP uses local-log-start-offset and Earliest Local
> Offset
> > > in
> > > > > > different places. It would be useful to standardize the
> terminology.
> > > > > >
> > > > > > Sure.
> > > > > >
> > > > > > 5106. The section on "In BuildingRemoteLogAux state". It listed
> two
> > > > > options
> > > > > > without saying which option is chosen.
> > > > > > We already mentioned in the KIP that we chose option-2.
> > > > > >
> > > > > > 5107. Follower to leader transition: It has step 2, but not step
> 1.
> > > > > > Step-1 is there but it is not explicitly highlighted. It is
> previous
> > > > > > table to step-2.
> > > > > >
> > > > > > 5108. If a consumer fetches from the remote data and the remote
> > > storage
> > > > > is
> > > > > > not available, what error code is used in the fetch response?
> > > > > >
> > > > > > Good point. We have not yet defined the error for this case. We
> need
> > > > > > to define an error message and send the same in fetch response.
> > > > > >
> > > > > > 5109. "ListOffsets: For timestamps >= 0, it returns the first
> message
> > > > > > offset whose timestamp is >= to the given timestamp in the
> request.
> > > That
> > > > > > means it checks in remote log time indexes first, after which
> local
> > > log
> > > > > > time indexes are checked." Could you document which method in
> RLMM is
> > > > > used
> > > > > > for this?
> > > > > >
> > > > > > Okay.
> > > > > >
> > > > > > 5110. Stopreplica: "it sets all the remote log segment metadata
> of
> > > that
> > > > > > partition with a delete marker and publishes them to RLMM." This
> > > seems
> > > > > > outdated given the new topic deletion logic.
> > > > > >
> > > > > > Will update with KIP-516 related points.
> > > > > >
> > > > > > 5111. "RLM follower fetches the earliest offset for the earliest
> > > leader
> > > > > > epoch by calling RLMM.earliestLogOffset(TopicPartition
> > > topicPartition,
> > > > > int
> > > > > > leaderEpoch) and updates that as the log start offset." Do we
> need
> > > that
> > > > > > since replication propagates logStartOffset already?
> > > > > >
> > > > > > Good point. Right, existing replication protocol takes care of
> > > > > > updating the followers’s log start offset received from the
> leader.
> > > > > >
> > > > > > 5112. Is the default maxWaitMs of 500ms enough for fetching from
> > > remote
> > > > > > storage?
> > > > > >
> > > > > > Remote reads may fail within the current default wait time, but
> > > > > > subsequent fetches would be able to serve as that data is stored
> in
> > > > > > the local cache. This cache is currently implemented in RSMs.
> But we
> > > > > > plan to pull this into the remote log messaging layer in future.
> > > > > >
> > > > > > 5113. "Committed offsets can be stored in a local file to avoid
> > > reading
> > > > > the
> > > > > > messages again when a broker is restarted." Could you describe
> the
> > > format
> > > > > > and the location of the file? Also, could the same message be
> > > processed
> > > > > by
> > > > > > RLMM again after broker restart? If so, how do we handle that?
> > > > > >
> > > > > > Sure, we will update in the KIP.
> > > > > >
> > > > > > 5114. Message format
> > > > > > 5114.1 There are two records named RemoteLogSegmentMetadataRecord
> > > with
> > > > > > apiKey 0 and 1.
> > > > > >
> > > > > > Nice catch, that was a typo. Fixed in the wiki.
> > > > > >
> > > > > > 5114.2 RemoteLogSegmentMetadataRecord: Could we document whether
> > > > > endOffset
> > > > > > is inclusive/exclusive?
> > > > > > It is inclusive, will update.
> > > > > >
> > > > > > 5114.3 RemoteLogSegmentMetadataRecord: Could you explain
> LeaderEpoch
> > > a
> > > > > bit
> > > > > > more? Is that the epoch of the leader when it copies the segment
> to
> > > > > remote
> > > > > > storage? Also, how will this field be used?
> > > > > >
> > > > > > Right, this is the leader epoch of the broker which copied this
> > > > > > segment. This is helpful in reason about which broker copied the
> > > > > > segment to remote storage.
> > > > > >
> > > > > > 5114.4 EventTimestamp: Could you explain this a bit more? Each
> > > record in
> > > > > > Kafka already has a timestamp field. Could we just use that?
> > > > > >
> > > > > > This is the  timestamp at which  the respective event occurred.
> Added
> > > > > > this  to RemoteLogSegmentMetadata as RLMM can be  any other
> > > > > > implementation. We thought about that but it looked cleaner to
> use at
> > > > > > the message structure level instead of getting that from the
> consumer
> > > > > > record and using that to build the respective event.
> > > > > >
> > > > > >
> > > > > > 5114.5 SegmentSizeInBytes: Could this just be int32?
> > > > > >
> > > > > > Right, it looks like config allows only int value >= 14.
> > > > > >
> > > > > > 5115. RemoteLogCleaner(RLC): This could be confused with the log
> > > cleaner
> > > > > > for compaction. Perhaps it can be renamed to sth like
> > > > > > RemotePartitionRemover.
> > > > > >
> > > > > > I am fine with RemotePartitionRemover or
> RemoteLogDeletionManager(we
> > > > > > have other manager classes like RLM, RLMM).
> > > > > >
> > > > > > 5116. "RLC receives the delete_partition_marked and processes it
> if
> > > it is
> > > > > > not yet processed earlier." How does it know whether
> > > > > > delete_partition_marked has been processed earlier?
> > > > > >
> > > > > > This is to handle duplicate delete_partition_marked events. RLC
> > > > > > internally maintains a state for the delete_partition events and
> if
> > > it
> > > > > > already has an existing event then it ignores if it is already
> being
> > > > > > processed.
> > > > > >
> > > > > > 5117. Should we add a new MessageFormatter to read the tier
> metadata
> > > > > topic?
> > > > > >
> > > > > > Right, this is in plan but did not mention it in the KIP. This
> will
> > > be
> > > > > > useful for debugging purposes too.
> > > > > >
> > > > > > 5118. "Maximum remote log reader thread pool task queue size. If
> the
> > > task
> > > > > > queue is full, broker will stop reading remote log segments."
> What
> > > do we
> > > > > > return to the fetch request in this case?
> > > > > >
> > > > > > We return an error response for that partition.
> > > > > >
> > > > > > 5119. It would be useful to list all things not supported in the
> > > first
> > > > > > version in a Future work or Limitations section. For example,
> > > compacted
> > > > > > topic, JBOD, changing remote.log.storage.enable from true to
> false,
> > > etc.
> > > > > >
> > > > > > We already have a non-goals section which is filled with some of
> > > these
> > > > > > details. Do we need another limitations section?
> > > > > >
> > > > > > Thanks,
> > > > > > Satish.
> > > > > >
> > > > > > On Wed, Nov 4, 2020 at 11:27 PM Jun Rao <ju...@confluent.io>
> wrote:
> > > > > > >
> > > > > > > Hi, Satish,
> > > > > > >
> > > > > > > Thanks for the updated KIP. A few more comments below.
> > > > > > >
> > > > > > > 605.2 "Build the local leader epoch cache by cutting the leader
> > > epoch
> > > > > > > sequence received from remote storage to [LSO, ELO]." I
> mentioned
> > > an
> > > > > issue
> > > > > > > earlier. Suppose the leader's local start offset is 100. The
> > > follower
> > > > > finds
> > > > > > > a remote segment covering offset range [80, 120). The
> producerState
> > > > > with
> > > > > > > this remote segment is up to offset 120. To trim the
> producerState
> > > to
> > > > > > > offset 100 requires more work since one needs to download the
> > > previous
> > > > > > > producerState up to offset 80 and then replay the messages
> from 80
> > > to
> > > > > 100.
> > > > > > > It seems that it's simpler in this case for the follower just
> to
> > > take
> > > > > the
> > > > > > > remote segment as it is and start fetching from offset 120.
> > > > > > >
> > > > > > > 5016. Just to echo what Kowshik was saying. It seems that
> > > > > > > RLMM.onPartitionLeadershipChanges() is only called on the
> replicas
> > > for
> > > > > a
> > > > > > > partition, not on the replicas for the
> > > __remote_log_segment_metadata
> > > > > > > partition. It's not clear how the leader of
> > > > > __remote_log_segment_metadata
> > > > > > > obtains the metadata for remote segments for deletion.
> > > > > > >
> > > > > > > 5100. KIP-516 has been accepted and is being implemented now.
> > > Could you
> > > > > > > update the KIP based on topicID?
> > > > > > >
> > > > > > > 5101. RLMM: It would be useful to clarify how the following two
> > > APIs
> > > > > are
> > > > > > > used. According to the wiki, the former is used for topic
> deletion
> > > and
> > > > > the
> > > > > > > latter is used for retention. It seems that retention should
> use
> > > the
> > > > > former
> > > > > > > since remote segments without a matching epoch in the leader
> > > > > (potentially
> > > > > > > due to unclean leader election) also need to be garbage
> collected.
> > > The
> > > > > > > latter seems to be used for the new leader to determine the
> last
> > > tiered
> > > > > > > segment.
> > > > > > >     default Iterator<RemoteLogSegmentMetadata>
> > > > > > > listRemoteLogSegments(TopicPartition topicPartition)
> > > > > > >     Iterator<RemoteLogSegmentMetadata>
> > > > > listRemoteLogSegments(TopicPartition
> > > > > > > topicPartition, long leaderEpoch);
> > > > > > >
> > > > > > > 5102. RSM:
> > > > > > > 5102.1 For methods like fetchLogSegmentData(), it seems that
> they
> > > can
> > > > > > > use RemoteLogSegmentId instead of RemoteLogSegmentMetadata.
> > > > > > > 5102.2 In fetchLogSegmentData(), should we use long instead of
> > > Long?
> > > > > > > 5102.3 Why only some of the methods have default
> implementation and
> > > > > others
> > > > > > > don't?
> > > > > > > 5102.4. Could we define RemoteLogSegmentMetadataUpdate
> > > > > > > and DeletePartitionUpdate?
> > > > > > > 5102.5 LogSegmentData: It seems that it's easier to pass
> > > > > > > in leaderEpochIndex as a ByteBuffer or byte array than a file
> > > since it
> > > > > will
> > > > > > > be generated in memory.
> > > > > > > 5102.6 RemoteLogSegmentMetadata: It seems that it needs both
> > > > > baseOffset and
> > > > > > > startOffset. For example, deleteRecords() could move the
> > > startOffset
> > > > > to the
> > > > > > > middle of a segment. If we copy the full segment to remote
> > > storage, the
> > > > > > > baseOffset and the startOffset will be different.
> > > > > > > 5102.7 Could we define all the public methods for
> > > > > RemoteLogSegmentMetadata
> > > > > > > and LogSegmentData?
> > > > > > > 5102.8 Could we document whether endOffset in
> > > RemoteLogSegmentMetadata
> > > > > is
> > > > > > > inclusive/exclusive?
> > > > > > >
> > > > > > > 5103. configs:
> > > > > > > 5103.1 Could we define the default value of non-required
> configs
> > > (e.g
> > > > > the
> > > > > > > size of new thread pools)?
> > > > > > > 5103.2 It seems that local.log.retention.ms should default to
> > > > > retention.ms,
> > > > > > > instead of remote.log.retention.minutes. Similarly, it seems
> > > > > > > that local.log.retention.bytes should default to segment.bytes.
> > > > > > > 5103.3 remote.log.manager.thread.pool.size: The description
> says
> > > "used
> > > > > in
> > > > > > > scheduling tasks to copy segments, fetch remote log indexes and
> > > clean
> > > > > up
> > > > > > > remote log segments". However, there is a separate
> > > > > > > config remote.log.reader.threads for fetching remote data. It's
> > > weird
> > > > > to
> > > > > > > fetch remote index and log in different thread pools since
> both are
> > > > > used
> > > > > > > for serving fetch requests.
> > > > > > > 5103.4 remote.log.manager.task.interval.ms: Is that the
> amount of
> > > > > time to
> > > > > > > back off when there is no work to do? If so, perhaps it can be
> > > renamed
> > > > > as
> > > > > > > backoff.ms.
> > > > > > > 5103.5 Are rlm_process_interval_ms and rlm_retry_interval_ms
> > > configs?
> > > > > If
> > > > > > > so, they need to be listed in this section.
> > > > > > >
> > > > > > > 5104. "RLM maintains a bounded cache(possibly LRU) of the index
> > > files
> > > > > of
> > > > > > > remote log segments to avoid multiple index fetches from the
> remote
> > > > > > > storage." Is the RLM in memory or on disk? If on disk, where
> is it
> > > > > stored?
> > > > > > > Do we need a configuration to bound the size?
> > > > > > >
> > > > > > > 5105. The KIP uses local-log-start-offset and Earliest Local
> > > Offset in
> > > > > > > different places. It would be useful to standardize the
> > > terminology.
> > > > > > >
> > > > > > > 5106. The section on "In BuildingRemoteLogAux state". It
> listed two
> > > > > options
> > > > > > > without saying which option is chosen.
> > > > > > >
> > > > > > > 5107. Follower to leader transition: It has step 2, but not
> step 1.
> > > > > > >
> > > > > > > 5108. If a consumer fetches from the remote data and the remote
> > > > > storage is
> > > > > > > not available, what error code is used in the fetch response?
> > > > > > >
> > > > > > > 5109. "ListOffsets: For timestamps >= 0, it returns the first
> > > message
> > > > > > > offset whose timestamp is >= to the given timestamp in the
> request.
> > > > > That
> > > > > > > means it checks in remote log time indexes first, after which
> > > local log
> > > > > > > time indexes are checked." Could you document which method in
> RLMM
> > > is
> > > > > used
> > > > > > > for this?
> > > > > > >
> > > > > > > 5110. Stopreplica: "it sets all the remote log segment
> metadata of
> > > that
> > > > > > > partition with a delete marker and publishes them to RLMM."
> This
> > > seems
> > > > > > > outdated given the new topic deletion logic.
> > > > > > >
> > > > > > > 5111. "RLM follower fetches the earliest offset for the
> earliest
> > > leader
> > > > > > > epoch by calling RLMM.earliestLogOffset(TopicPartition
> > > topicPartition,
> > > > > int
> > > > > > > leaderEpoch) and updates that as the log start offset." Do we
> need
> > > that
> > > > > > > since replication propagates logStartOffset already?
> > > > > > >
> > > > > > > 5112. Is the default maxWaitMs of 500ms enough for fetching
> from
> > > remote
> > > > > > > storage?
> > > > > > >
> > > > > > > 5113. "Committed offsets can be stored in a local file to avoid
> > > > > reading the
> > > > > > > messages again when a broker is restarted." Could you describe
> the
> > > > > format
> > > > > > > and the location of the file? Also, could the same message be
> > > > > processed by
> > > > > > > RLMM again after broker restart? If so, how do we handle that?
> > > > > > >
> > > > > > > 5114. Message format
> > > > > > > 5114.1 There are two records named
> RemoteLogSegmentMetadataRecord
> > > with
> > > > > > > apiKey 0 and 1.
> > > > > > > 5114.2 RemoteLogSegmentMetadataRecord: Could we document
> whether
> > > > > endOffset
> > > > > > > is inclusive/exclusive?
> > > > > > > 5114.3 RemoteLogSegmentMetadataRecord: Could you explain
> > > LeaderEpoch a
> > > > > bit
> > > > > > > more? Is that the epoch of the leader when it copies the
> segment to
> > > > > remote
> > > > > > > storage? Also, how will this field be used?
> > > > > > > 5114.4 EventTimestamp: Could you explain this a bit more? Each
> > > record
> > > > > in
> > > > > > > Kafka already has a timestamp field. Could we just use that?
> > > > > > > 5114.5 SegmentSizeInBytes: Could this just be int32?
> > > > > > >
> > > > > > > 5115. RemoteLogCleaner(RLC): This could be confused with the
> log
> > > > > cleaner
> > > > > > > for compaction. Perhaps it can be renamed to sth like
> > > > > > > RemotePartitionRemover.
> > > > > > >
> > > > > > > 5116. "RLC receives the delete_partition_marked and processes
> it
> > > if it
> > > > > is
> > > > > > > not yet processed earlier." How does it know whether
> > > > > > > delete_partition_marked has been processed earlier?
> > > > > > >
> > > > > > > 5117. Should we add a new MessageFormatter to read the tier
> > > metadata
> > > > > topic?
> > > > > > >
> > > > > > > 5118. "Maximum remote log reader thread pool task queue size.
> If
> > > the
> > > > > task
> > > > > > > queue is full, broker will stop reading remote log segments."
> What
> > > do
> > > > > we
> > > > > > > return to the fetch request in this case?
> > > > > > >
> > > > > > > 5119. It would be useful to list all things not supported in
> the
> > > first
> > > > > > > version in a Future work or Limitations section. For example,
> > > compacted
> > > > > > > topic, JBOD, changing remote.log.storage.enable from true to
> false,
> > > > > etc.
> > > > > > >
> > > > > > > Thanks,
> > > > > > >
> > > > > > > Jun
> > > > > > >
> > > > > > > On Tue, Oct 27, 2020 at 5:57 PM Kowshik Prakasam <
> > > > > kprakasam@confluent.io>
> > > > > > > wrote:
> > > > > > >
> > > > > > > > Hi Satish,
> > > > > > > >
> > > > > > > > Thanks for the updates to the KIP. Here are my first batch of
> > > > > > > > comments/suggestions on the latest version of the KIP.
> > > > > > > >
> > > > > > > > 5012. In the RemoteStorageManager interface, there is an API
> > > defined
> > > > > for
> > > > > > > > each file type. For example, fetchOffsetIndex,
> > > fetchTimestampIndex
> > > > > etc. To
> > > > > > > > avoid the duplication, I'd suggest we can instead have a
> FileType
> > > > > enum and
> > > > > > > > a common get API based on the FileType.
> > > > > > > >
> > > > > > > > 5013. There are some references to the Google doc in the
> KIP. I
> > > > > wasn't sure
> > > > > > > > if the Google doc is expected to be in sync with the
> contents of
> > > the
> > > > > wiki.
> > > > > > > > Going forward, it seems easier if just the KIP is maintained
> as
> > > the
> > > > > source
> > > > > > > > of truth. In this regard, could you please move all the
> > > references
> > > > > to the
> > > > > > > > Google doc, maybe to a separate References section at the
> bottom
> > > of
> > > > > the
> > > > > > > > KIP?
> > > > > > > >
> > > > > > > > 5014. There are some TODO sections in the KIP. Would these be
> > > filled
> > > > > up in
> > > > > > > > future iterations?
> > > > > > > >
> > > > > > > > 5015. Under "Topic deletion lifecycle", I'm trying to
> understand
> > > why
> > > > > do we
> > > > > > > > need delete_partition_marked as well as the
> > > delete_partition_started
> > > > > > > > messages. I couldn't spot a drawback if supposing we
> simplified
> > > the
> > > > > design
> > > > > > > > such that the controller would only write
> > > delete_partition_started
> > > > > message,
> > > > > > > > and RemoteLogCleaner (RLC) instance picks it up for
> processing.
> > > What
> > > > > am I
> > > > > > > > missing?
> > > > > > > >
> > > > > > > > 5016. Under "Topic deletion lifecycle", step (4) is
> mentioned as
> > > > > "RLC gets
> > > > > > > > all the remote log segments for the partition and each of
> these
> > > > > remote log
> > > > > > > > segments is deleted with the next steps.". Since the RLC
> instance
> > > > > runs on
> > > > > > > > each tier topic partition leader, how does the RLC then get
> the
> > > list
> > > > > of
> > > > > > > > remote log segments to be deleted? It will be useful to add
> that
> > > > > detail to
> > > > > > > > the KIP.
> > > > > > > >
> > > > > > > > 5017. Under "Public Interfaces -> Configs", there is a line
> > > > > mentioning "We
> > > > > > > > will support flipping remote.log.storage.enable in next
> > > versions."
> > > > > It will
> > > > > > > > be useful to mention this in the "Future Work" section of
> the KIP
> > > > > too.
> > > > > > > >
> > > > > > > > 5018. The KIP introduces a number of configuration
> parameters. It
> > > > > will be
> > > > > > > > useful to mention in the KIP if the user should assume these
> as
> > > > > static
> > > > > > > > configuration in the server.properties file, or dynamic
> > > > > configuration which
> > > > > > > > can be modified without restarting the broker.
> > > > > > > >
> > > > > > > > 5019.  Maybe this is planned as a future update to the KIP,
> but I
> > > > > thought
> > > > > > > > I'd mention it here. Could you please add details to the KIP
> on
> > > why
> > > > > RocksDB
> > > > > > > > was chosen as the default cache implementation of RLMM, and
> how
> > > it
> > > > > is going
> > > > > > > > to be used? Were alternatives compared/considered? For
> example,
> > > it
> > > > > would be
> > > > > > > > useful to explain/evaluate the following: 1) debuggability
> of the
> > > > > RocksDB
> > > > > > > > JNI interface, 2) performance, 3) portability across
> platforms
> > > and 4)
> > > > > > > > interface parity of RocksDB’s JNI api with it's underlying
> C/C++
> > > api.
> > > > > > > >
> > > > > > > > 5020. Following up on (5019), for the RocksDB cache, it will
> be
> > > > > useful to
> > > > > > > > explain the relationship/mapping between the following in the
> > > KIP:
> > > > > 1) # of
> > > > > > > > tiered partitions, 2) # of partitions of metadata topic
> > > > > > > > __remote_log_metadata and 3) # of RocksDB instances. i.e. is
> the
> > > > > plan to
> > > > > > > > have a RocksDB instance per tiered partition, or per metadata
> > > topic
> > > > > > > > partition, or just 1 for per broker?
> > > > > > > >
> > > > > > > > 5021. I was looking at the implementation prototype (PR link:
> > > > > > > > https://github.com/apache/kafka/pull/7561). It seems that a
> > > boolean
> > > > > > > > attribute is being introduced into the Log layer to check if
> > > remote
> > > > > log
> > > > > > > > capability is enabled. While the boolean footprint is small
> at
> > > the
> > > > > moment,
> > > > > > > > this can easily grow in the future and become harder to
> > > > > > > > test/maintain, considering that the Log layer is already
> pretty
> > > > > complex. We
> > > > > > > > should start thinking about how to manage such changes to
> the Log
> > > > > layer
> > > > > > > > (for the purpose of improved testability, better separation
> of
> > > > > concerns and
> > > > > > > > readability). One proposal I have is to take a step back and
> > > define a
> > > > > > > > higher level Log interface. Then, the Broker code can be
> changed
> > > to
> > > > > use
> > > > > > > > this interface. It can be changed such that only a handle to
> the
> > > > > interface
> > > > > > > > is exposed to other components (such as LogCleaner,
> > > ReplicaManager
> > > > > etc.)
> > > > > > > > and not the underlying Log object. This approach keeps the
> user
> > > of
> > > > > the Log
> > > > > > > > layer agnostic of the whereabouts of the data. Underneath the
> > > > > interface,
> > > > > > > > the implementing classes can completely separate local log
> > > > > capabilities
> > > > > > > > from the remote log. For example, the Log class can be
> > > simplified to
> > > > > only
> > > > > > > > manage logic surrounding local log segments and metadata.
> > > > > Additionally, a
> > > > > > > > wrapper class can be provided (implementing the higher level
> Log
> > > > > interface)
> > > > > > > > which will contain any/all logic surrounding tiered data. The
> > > wrapper
> > > > > > > > class will wrap around an instance of the Log class
> delegating
> > > the
> > > > > local
> > > > > > > > log logic to it. Finally, a handle to the wrapper class can
> be
> > > > > exposed to
> > > > > > > > the other components wherever they need a handle to the
> higher
> > > level
> > > > > Log
> > > > > > > > interface.
> > > > > > > >
> > > > > > > >
> > > > > > > > Cheers,
> > > > > > > > Kowshik
> > > > > > > >
> > > > > > > > On Mon, Oct 26, 2020 at 9:52 PM Satish Duggana <
> > > > > satish.duggana@gmail.com>
> > > > > > > > wrote:
> > > > > > > >
> > > > > > > > > Hi,
> > > > > > > > > KIP is updated with 1) topic deletion lifecycle and its
> related
> > > > > items
> > > > > > > > > 2) Protocol changes(mainly related to ListOffsets) and
> other
> > > minor
> > > > > > > > > changes.
> > > > > > > > > Please go through them and let us know your comments.
> > > > > > > > >
> > > > > > > > > Thanks,
> > > > > > > > > Satish.
> > > > > > > > >
> > > > > > > > > On Mon, Sep 28, 2020 at 9:10 PM Satish Duggana <
> > > > > satish.duggana@gmail.com
> > > > > > > > >
> > > > > > > > > wrote:
> > > > > > > > > >
> > > > > > > > > > Hi Dhruvil,
> > > > > > > > > > Thanks for looking into the KIP and sending your
> comments.
> > > Sorry
> > > > > for
> > > > > > > > > > the late reply, missed it in the mail thread.
> > > > > > > > > >
> > > > > > > > > > 1. Could you describe how retention would work with this
> KIP
> > > and
> > > > > which
> > > > > > > > > > threads are responsible for driving this work? I believe
> > > there
> > > > > are 3
> > > > > > > > > kinds
> > > > > > > > > > of retention processes we are looking at:
> > > > > > > > > >   (a) Regular retention for data in tiered storage as per
> > > > > configured `
> > > > > > > > > > retention.ms` / `retention.bytes`.
> > > > > > > > > >   (b) Local retention for data in local storage as per
> > > > > configured `
> > > > > > > > > > local.log.retention.ms` / `local.log.retention.bytes`
> > > > > > > > > >   (c) Possibly regular retention for data in local
> storage,
> > > if
> > > > > the
> > > > > > > > > tiering
> > > > > > > > > > task is lagging or for data that is below the log start
> > > offset.
> > > > > > > > > >
> > > > > > > > > > Local log retention is done by the existing log cleanup
> > > tasks.
> > > > > These
> > > > > > > > > > are not done for segments that are not yet copied to
> remote
> > > > > storage.
> > > > > > > > > > Remote log cleanup is done by the leader partition’s
> RLMTask.
> > > > > > > > > >
> > > > > > > > > > 2. When does a segment become eligible to be tiered? Is
> it as
> > > > > soon as
> > > > > > > > the
> > > > > > > > > > segment is rolled and the end offset is less than the
> last
> > > stable
> > > > > > > > offset
> > > > > > > > > as
> > > > > > > > > > mentioned in the KIP? I wonder if we need to consider
> other
> > > > > parameters
> > > > > > > > > too,
> > > > > > > > > > like the highwatermark so that we are guaranteed that
> what
> > > we are
> > > > > > > > tiering
> > > > > > > > > > has been committed to the log and accepted by the ISR.
> > > > > > > > > >
> > > > > > > > > > AFAIK, last stable offset is always <= highwatermark.
> This
> > > will
> > > > > make
> > > > > > > > > > sure we are always tiering the message segments which
> have
> > > been
> > > > > > > > > > accepted by ISR and transactionally completed.
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > 3. The section on "Follower Fetch Scenarios" is useful
> but
> > > is a
> > > > > bit
> > > > > > > > > > difficult to parse at the moment. It would be useful to
> > > > > summarize the
> > > > > > > > > > changes we need in the ReplicaFetcher.
> > > > > > > > > >
> > > > > > > > > > It may become difficult for users to read/follow if we
> add
> > > code
> > > > > changes
> > > > > > > > > here.
> > > > > > > > > >
> > > > > > > > > > 4. Related to the above, it's a bit unclear how we are
> > > planning
> > > > > on
> > > > > > > > > > restoring the producer state for a new replica. Could you
> > > expand
> > > > > on
> > > > > > > > that?
> > > > > > > > > >
> > > > > > > > > > It is mentioned in the KIP BuildingRemoteLogAuxState is
> > > > > introduced to
> > > > > > > > > > build the state like leader epoch sequence and producer
> > > snapshots
> > > > > > > > > > before it starts fetching the data from the leader. We
> will
> > > make
> > > > > it
> > > > > > > > > > clear in the KIP.
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > 5. Similarly, it would be worth summarizing the behavior
> on
> > > > > unclean
> > > > > > > > > leader
> > > > > > > > > > election. There are several scenarios to consider here:
> data
> > > > > loss from
> > > > > > > > > > local log, data loss from remote log, data loss from
> metadata
> > > > > topic,
> > > > > > > > etc.
> > > > > > > > > > It's worth describing these in detail.
> > > > > > > > > >
> > > > > > > > > > We mentioned the cases about unclean leader election in
> the
> > > > > follower
> > > > > > > > > > fetch scenarios.
> > > > > > > > > > If there are errors while fetching data from remote
> store or
> > > > > metadata
> > > > > > > > > > store, it will work the same way as it works with local
> log.
> > > It
> > > > > > > > > > returns the error back to the caller. Please let us know
> if
> > > I am
> > > > > > > > > > missing your point here.
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > 7. For a READ_COMMITTED FetchRequest, how do we retrieve
> and
> > > > > return the
> > > > > > > > > > aborted transaction metadata?
> > > > > > > > > >
> > > > > > > > > > When a fetch for a remote log is accessed, we will fetch
> > > aborted
> > > > > > > > > > transactions along with the segment if it is not found
> in the
> > > > > local
> > > > > > > > > > index cache. This includes the case of transaction index
> not
> > > > > existing
> > > > > > > > > > in the remote log segment. That means, the cache entry
> can be
> > > > > empty or
> > > > > > > > > > have a list of aborted transactions.
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > 8. The `LogSegmentData` class assumes that we have a log
> > > segment,
> > > > > > > > offset
> > > > > > > > > > index, time index, transaction index, producer snapshot
> and
> > > > > leader
> > > > > > > > epoch
> > > > > > > > > > index. How do we deal with cases where we do not have
> one or
> > > > > more of
> > > > > > > > > these?
> > > > > > > > > > For example, we may not have a transaction index or
> producer
> > > > > snapshot
> > > > > > > > > for a
> > > > > > > > > > particular segment. The former is optional, and the
> latter is
> > > > > only kept
> > > > > > > > > for
> > > > > > > > > > up to the 3 latest segments.
> > > > > > > > > >
> > > > > > > > > > This is a good point,  we discussed this in the last
> meeting.
> > > > > > > > > > Transaction index is optional and we will copy them only
> if
> > > it
> > > > > exists.
> > > > > > > > > > We want to keep all the producer snapshots at each log
> > > segment
> > > > > rolling
> > > > > > > > > > and they can be removed if the log copying is successful
> and
> > > it
> > > > > still
> > > > > > > > > > maintains the existing latest 3 segments, We only delete
> the
> > > > > producer
> > > > > > > > > > snapshots which have been copied to remote log segments
> on
> > > > > leader.
> > > > > > > > > > Follower will keep the log segments beyond the segments
> which
> > > > > have not
> > > > > > > > > > been copied to remote storage. We will update the KIP
> with
> > > these
> > > > > > > > > > details.
> > > > > > > > > >
> > > > > > > > > > Thanks,
> > > > > > > > > > Satish.
> > > > > > > > > >
> > > > > > > > > > On Thu, Sep 17, 2020 at 1:47 AM Dhruvil Shah <
> > > > > dhruvil@confluent.io>
> > > > > > > > > wrote:
> > > > > > > > > > >
> > > > > > > > > > > Hi Satish, Harsha,
> > > > > > > > > > >
> > > > > > > > > > > Thanks for the KIP. Few questions below:
> > > > > > > > > > >
> > > > > > > > > > > 1. Could you describe how retention would work with
> this
> > > KIP
> > > > > and
> > > > > > > > which
> > > > > > > > > > > threads are responsible for driving this work? I
> believe
> > > there
> > > > > are 3
> > > > > > > > > kinds
> > > > > > > > > > > of retention processes we are looking at:
> > > > > > > > > > >   (a) Regular retention for data in tiered storage as
> per
> > > > > configured
> > > > > > > > `
> > > > > > > > > > > retention.ms` / `retention.bytes`.
> > > > > > > > > > >   (b) Local retention for data in local storage as per
> > > > > configured `
> > > > > > > > > > > local.log.retention.ms` / `local.log.retention.bytes`
> > > > > > > > > > >   (c) Possibly regular retention for data in local
> > > storage, if
> > > > > the
> > > > > > > > > tiering
> > > > > > > > > > > task is lagging or for data that is below the log start
> > > offset.
> > > > > > > > > > >
> > > > > > > > > > > 2. When does a segment become eligible to be tiered?
> Is it
> > > as
> > > > > soon as
> > > > > > > > > the
> > > > > > > > > > > segment is rolled and the end offset is less than the
> last
> > > > > stable
> > > > > > > > > offset as
> > > > > > > > > > > mentioned in the KIP? I wonder if we need to consider
> other
> > > > > > > > parameters
> > > > > > > > > too,
> > > > > > > > > > > like the highwatermark so that we are guaranteed that
> what
> > > we
> > > > > are
> > > > > > > > > tiering
> > > > > > > > > > > has been committed to the log and accepted by the ISR.
> > > > > > > > > > >
> > > > > > > > > > > 3. The section on "Follower Fetch Scenarios" is useful
> but
> > > is
> > > > > a bit
> > > > > > > > > > > difficult to parse at the moment. It would be useful to
> > > > > summarize the
> > > > > > > > > > > changes we need in the ReplicaFetcher.
> > > > > > > > > > >
> > > > > > > > > > > 4. Related to the above, it's a bit unclear how we are
> > > > > planning on
> > > > > > > > > > > restoring the producer state for a new replica. Could
> you
> > > > > expand on
> > > > > > > > > that?
> > > > > > > > > > >
> > > > > > > > > > > 5. Similarly, it would be worth summarizing the
> behavior on
> > > > > unclean
> > > > > > > > > leader
> > > > > > > > > > > election. There are several scenarios to consider here:
> > > data
> > > > > loss
> > > > > > > > from
> > > > > > > > > > > local log, data loss from remote log, data loss from
> > > metadata
> > > > > topic,
> > > > > > > > > etc.
> > > > > > > > > > > It's worth describing these in detail.
> > > > > > > > > > >
> > > > > > > > > > > 6. It would be useful to add details about how we plan
> on
> > > using
> > > > > > > > > RocksDB in
> > > > > > > > > > > the default implementation of
> `RemoteLogMetadataManager`.
> > > > > > > > > > >
> > > > > > > > > > > 7. For a READ_COMMITTED FetchRequest, how do we
> retrieve
> > > and
> > > > > return
> > > > > > > > the
> > > > > > > > > > > aborted transaction metadata?
> > > > > > > > > > >
> > > > > > > > > > > 8. The `LogSegmentData` class assumes that we have a
> log
> > > > > segment,
> > > > > > > > > offset
> > > > > > > > > > > index, time index, transaction index, producer
> snapshot and
> > > > > leader
> > > > > > > > > epoch
> > > > > > > > > > > index. How do we deal with cases where we do not have
> one
> > > or
> > > > > more of
> > > > > > > > > these?
> > > > > > > > > > > For example, we may not have a transaction index or
> > > producer
> > > > > snapshot
> > > > > > > > > for a
> > > > > > > > > > > particular segment. The former is optional, and the
> latter
> > > is
> > > > > only
> > > > > > > > > kept for
> > > > > > > > > > > up to the 3 latest segments.
> > > > > > > > > > >
> > > > > > > > > > > Thanks,
> > > > > > > > > > > Dhruvil
> > > > > > > > > > >
> > > > > > > > > > > On Mon, Sep 7, 2020 at 6:54 PM Harsha Ch <
> > > harsha.ch@gmail.com>
> > > > > > > > wrote:
> > > > > > > > > > >
> > > > > > > > > > > > Hi All,
> > > > > > > > > > > >
> > > > > > > > > > > > We are all working through the last meeting feedback.
> > > I'll
> > > > > cancel
> > > > > > > > the
> > > > > > > > > > > > tomorrow 's meeting and we can meanwhile continue our
> > > > > discussion in
> > > > > > > > > mailing
> > > > > > > > > > > > list. We can start the regular meeting from next week
> > > > > onwards.
> > > > > > > > > > > >
> > > > > > > > > > > > Thanks,
> > > > > > > > > > > >
> > > > > > > > > > > > Harsha
> > > > > > > > > > > >
> > > > > > > > > > > > On Fri, Sep 04, 2020 at 8:41 AM, Satish Duggana <
> > > > > > > > > satish.duggana@gmail.com
> > > > > > > > > > > > > wrote:
> > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > Hi Jun,
> > > > > > > > > > > > > Thanks for your thorough review and comments.
> Please
> > > find
> > > > > the
> > > > > > > > > inline
> > > > > > > > > > > > > replies below.
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > 600. The topic deletion logic needs more details.
> > > > > > > > > > > > > 600.1 The KIP mentions "The controller considers
> the
> > > topic
> > > > > > > > > partition is
> > > > > > > > > > > > > deleted only when it determines that there are no
> log
> > > > > segments
> > > > > > > > for
> > > > > > > > > that
> > > > > > > > > > > > > topic partition by using RLMM". How is this done?
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > It uses RLMM#listSegments() returns all the
> segments
> > > for
> > > > > the
> > > > > > > > given
> > > > > > > > > topic
> > > > > > > > > > > > > partition.
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > 600.2 "If the delete option is enabled then the
> leader
> > > > > will stop
> > > > > > > > > RLM task
> > > > > > > > > > > > > and stop processing and it sets all the remote log
> > > segment
> > > > > > > > > metadata of
> > > > > > > > > > > > > that partition with a delete marker and publishes
> them
> > > to
> > > > > RLMM."
> > > > > > > > We
> > > > > > > > > > > > > discussed this earlier. When a topic is being
> deleted,
> > > > > there may
> > > > > > > > > not be a
> > > > > > > > > > > > > leader for the deleted partition.
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > This is a good point. As suggested in the meeting,
> we
> > > will
> > > > > add a
> > > > > > > > > separate
> > > > > > > > > > > > > section for topic/partition deletion lifecycle and
> this
> > > > > scenario
> > > > > > > > > will be
> > > > > > > > > > > > > addressed.
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > 601. Unclean leader election
> > > > > > > > > > > > > 601.1 Scenario 1: new empty follower
> > > > > > > > > > > > > After step 1, the follower restores up to offset
> 3. So
> > > why
> > > > > does
> > > > > > > > it
> > > > > > > > > have
> > > > > > > > > > > > > LE-2 <https://issues.apache.org/jira/browse/LE-2>
> at
> > > > > offset 5?
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > Nice catch. It was showing the leader epoch fetched
> > > from
> > > > > the
> > > > > > > > remote
> > > > > > > > > > > > > storage. It should be shown with the truncated till
> > > offset
> > > > > 3.
> > > > > > > > > Updated the
> > > > > > > > > > > > > KIP.
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > 601.2 senario 5: After Step 3, leader A has
> > > inconsistent
> > > > > data
> > > > > > > > > between its
> > > > > > > > > > > > > local and the tiered data. For example. offset 3
> has
> > > msg 3
> > > > > LE-0
> > > > > > > > > <https://issues.apache.org/jira/browse/LE-0> locally,
> > > > > > > > > > > > > but msg 5 LE-1 <
> > > https://issues.apache.org/jira/browse/LE-1>
> > > > > in
> > > > > > > > > the remote store. While it's ok for the unclean leader
> > > > > > > > > > > > > to lose data, it should still return consistent
> data,
> > > > > whether
> > > > > > > > it's
> > > > > > > > > from
> > > > > > > > > > > > > the local or the remote store.
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > There is no inconsistency here as LE-0
> > > > > > > > > <https://issues.apache.org/jira/browse/LE-0> offsets are
> [0,
> > > 4]
> > > > > and LE-2
> > > > > > > > > <https://issues.apache.org/jira/browse/LE-2>:
> > > > > > > > > > > > > [5, ]. It will always get the right records for the
> > > given
> > > > > offset
> > > > > > > > > and
> > > > > > > > > > > > > leader epoch. In case of remote, RSM is invoked to
> get
> > > the
> > > > > remote
> > > > > > > > > log
> > > > > > > > > > > > > segment that contains the given offset with the
> leader
> > > > > epoch.
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > 601.4 It seems that retention is based on
> > > > > > > > > > > > > listRemoteLogSegments(TopicPartition
> topicPartition,
> > > long
> > > > > > > > > leaderEpoch).
> > > > > > > > > > > > > When there is an unclean leader election, it's
> possible
> > > > > for the
> > > > > > > > new
> > > > > > > > > > > > leader
> > > > > > > > > > > > > to not to include certain epochs in its epoch
> cache.
> > > How
> > > > > are
> > > > > > > > remote
> > > > > > > > > > > > > segments associated with those epochs being
> cleaned?
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > That is a good point. This leader will also
> cleanup the
> > > > > epochs
> > > > > > > > > earlier to
> > > > > > > > > > > > > its start leader epoch and delete those segments.
> It
> > > gets
> > > > > the
> > > > > > > > > earliest
> > > > > > > > > > > > > epoch for a partition and starts deleting segments
> from
> > > > > that
> > > > > > > > leader
> > > > > > > > > > > > epoch.
> > > > > > > > > > > > > We need one more API in RLMM to get the earliest
> leader
> > > > > epoch.
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > 601.5 The KIP discusses the handling of unclean
> leader
> > > > > elections
> > > > > > > > > for user
> > > > > > > > > > > > > topics. What about unclean leader elections on
> > > > > > > > > > > > > __remote_log_segment_metadata?
> > > > > > > > > > > > > This is the same as other system topics like
> > > > > consumer_offsets,
> > > > > > > > > > > > > __transaction_state topics. As discussed in the
> > > meeting,
> > > > > we will
> > > > > > > > > add the
> > > > > > > > > > > > > behavior of __remote_log_segment_metadata topic’s
> > > unclean
> > > > > leader
> > > > > > > > > > > > > truncation.
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > 602. It would be useful to clarify the limitations
> in
> > > the
> > > > > initial
> > > > > > > > > > > > release.
> > > > > > > > > > > > > The KIP mentions not supporting compacted topics.
> What
> > > > > about JBOD
> > > > > > > > > and
> > > > > > > > > > > > > changing the configuration of a topic from delete
> to
> > > > > compact
> > > > > > > > after
> > > > > > > > > > > > remote.
> > > > > > > > > > > > > log. storage. enable (
> > > http://remote.log.storage.enable/
> > > > > ) is
> > > > > > > > > enabled?
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > This was updated in the KIP earlier.
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > 603. RLM leader tasks:
> > > > > > > > > > > > > 603.1"It checks for rolled over LogSegments (which
> have
> > > > > the last
> > > > > > > > > message
> > > > > > > > > > > > > offset less than last stable offset of that topic
> > > > > partition) and
> > > > > > > > > copies
> > > > > > > > > > > > > them along with their offset/time/transaction
> indexes
> > > and
> > > > > leader
> > > > > > > > > epoch
> > > > > > > > > > > > > cache to the remote tier." It needs to copy the
> > > producer
> > > > > snapshot
> > > > > > > > > too.
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > Right. It copies producer snapshots too as
> mentioned in
> > > > > > > > > LogSegmentData.
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > 603.2 "Local logs are not cleaned up till those
> > > segments
> > > > > are
> > > > > > > > copied
> > > > > > > > > > > > > successfully to remote even though their retention
> > > > > time/size is
> > > > > > > > > reached"
> > > > > > > > > > > > > This seems weird. If the tiering stops because the
> > > remote
> > > > > store
> > > > > > > > is
> > > > > > > > > not
> > > > > > > > > > > > > available, we don't want the local data to grow
> > > forever.
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > It was clarified in the discussion that the
> comment was
> > > > > more
> > > > > > > > about
> > > > > > > > > the
> > > > > > > > > > > > > local storage goes beyond the log.retention. The
> above
> > > > > statement
> > > > > > > > > is about
> > > > > > > > > > > > > local.log.retention but not for the complete
> > > > > log.retention. When
> > > > > > > > it
> > > > > > > > > > > > > reaches the log.retention then it will delete the
> local
> > > > > logs even
> > > > > > > > > though
> > > > > > > > > > > > > those are not copied to remote storage.
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > 604. "RLM maintains a bounded cache(possibly LRU)
> of
> > > the
> > > > > index
> > > > > > > > > files of
> > > > > > > > > > > > > remote log segments to avoid multiple index fetches
> > > from
> > > > > the
> > > > > > > > remote
> > > > > > > > > > > > > storage. These indexes can be used in the same way
> as
> > > local
> > > > > > > > segment
> > > > > > > > > > > > > indexes are used." Could you provide more details
> on
> > > this?
> > > > > Are
> > > > > > > > the
> > > > > > > > > > > > indexes
> > > > > > > > > > > > > cached in memory or on disk? If on disk, where are
> they
> > > > > stored?
> > > > > > > > > Are the
> > > > > > > > > > > > > cached indexes bound by a certain size?
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > These are cached on disk and stored in log.dir
> with a
> > > name
> > > > > > > > > > > > > “__remote_log_index_cache”. They are bound by the
> total
> > > > > size.
> > > > > > > > This
> > > > > > > > > will
> > > > > > > > > > > > be
> > > > > > > > > > > > > exposed as a user configuration,
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > 605. BuildingRemoteLogAux
> > > > > > > > > > > > > 605.1 In this section, two options are listed.
> Which
> > > one is
> > > > > > > > chosen?
> > > > > > > > > > > > > Option-2, updated the KIP.
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > 605.2 In option 2, it says "Build the local leader
> > > epoch
> > > > > cache by
> > > > > > > > > cutting
> > > > > > > > > > > > > the leader epoch sequence received from remote
> storage
> > > to
> > > > > [LSO,
> > > > > > > > > ELO].
> > > > > > > > > > > > (LSO
> > > > > > > > > > > > >
> > > > > > > > > > > > > = log start offset)." We need to do the same thing
> for
> > > the
> > > > > > > > producer
> > > > > > > > > > > > > snapshot. However, it's hard to cut the producer
> > > snapshot
> > > > > to an
> > > > > > > > > earlier
> > > > > > > > > > > > > offset. Another option is to simply take the
> lastOffset
> > > > > from the
> > > > > > > > > remote
> > > > > > > > > > > > > segment and use that as the starting fetch offset
> in
> > > the
> > > > > > > > follower.
> > > > > > > > > This
> > > > > > > > > > > > > avoids the need for cutting.
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > Right, this was mentioned in the “transactional
> > > support”
> > > > > section
> > > > > > > > > about
> > > > > > > > > > > > > adding these details.
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > 606. ListOffsets: Since we need a version bump,
> could
> > > you
> > > > > > > > document
> > > > > > > > > it
> > > > > > > > > > > > > under a protocol change section?
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > Sure, we will update the KIP.
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > 607. "LogStartOffset of a topic can point to
> either of
> > > > > local
> > > > > > > > > segment or
> > > > > > > > > > > > > remote segment but it is initialised and
> maintained in
> > > the
> > > > > Log
> > > > > > > > > class like
> > > > > > > > > > > > > now. This is already maintained in `Log` class
> while
> > > > > loading the
> > > > > > > > > logs and
> > > > > > > > > > > > > it can also be fetched from
> RemoteLogMetadataManager."
> > > > > What will
> > > > > > > > > happen
> > > > > > > > > > > > to
> > > > > > > > > > > > > the existing logic (e.g. log recovery) that
> currently
> > > > > depends on
> > > > > > > > > > > > > logStartOffset but assumes it's local?
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > They use a field called localLogStartOffset which
> is
> > > the
> > > > > local
> > > > > > > > log
> > > > > > > > > start
> > > > > > > > > > > > > offset..
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > 608. Handle expired remote segment: How does it
> pick
> > > up new
> > > > > > > > > > > > logStartOffset
> > > > > > > > > > > > > from deleteRecords?
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > Good point. This was not addressed in the KIP. Will
> > > update
> > > > > the
> > > > > > > > KIP
> > > > > > > > > on how
> > > > > > > > > > > > > the RLM task handles this scenario.
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > 609. RLMM message format:
> > > > > > > > > > > > > 609.1 It includes both MaxTimestamp and
> EventTimestamp.
> > > > > Where
> > > > > > > > does
> > > > > > > > > it get
> > > > > > > > > > > > > both since the message in the log only contains one
> > > > > timestamp?
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > `EventTimeStamp` is the timestamp at which that
> segment
> > > > > metadata
> > > > > > > > > event is
> > > > > > > > > > > > > generated. This is more for audits.
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > 609.2 If we change just the state (e.g. to
> > > > > DELETE_STARTED), it
> > > > > > > > > seems it's
> > > > > > > > > > > > > wasteful to have to include all other fields not
> > > changed.
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > This is a good point. We thought about incremental
> > > > > updates. But
> > > > > > > > we
> > > > > > > > > want
> > > > > > > > > > > > to
> > > > > > > > > > > > > make sure all the events are in the expected order
> and
> > > take
> > > > > > > > action
> > > > > > > > > based
> > > > > > > > > > > > > on the latest event. Will think through the
> approaches
> > > in
> > > > > detail
> > > > > > > > > and
> > > > > > > > > > > > > update here.
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > 609.3 Could you document which process makes the
> > > following
> > > > > > > > > transitions
> > > > > > > > > > > > > DELETE_MARKED, DELETE_STARTED, DELETE_FINISHED?
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > Okay, will document more details.
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > 610. remote.log.reader.max.pending.tasks: "Maximum
> > > remote
> > > > > log
> > > > > > > > > reader
> > > > > > > > > > > > > thread pool task queue size. If the task queue is
> full,
> > > > > broker
> > > > > > > > > will stop
> > > > > > > > > > > > > reading remote log segments." What does the broker
> do
> > > if
> > > > > the
> > > > > > > > queue
> > > > > > > > > is
> > > > > > > > > > > > > full?
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > It returns an error for this topic partition.
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > 611. What do we return if the request offset/epoch
> > > doesn't
> > > > > exist
> > > > > > > > > in the
> > > > > > > > > > > > > following API?
> > > > > > > > > > > > > RemoteLogSegmentMetadata
> > > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > > > > > topicPartition, long offset, int epochForOffset)
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > This returns null. But we prefer to update the
> return
> > > type
> > > > > as
> > > > > > > > > Optional
> > > > > > > > > > > > and
> > > > > > > > > > > > > return Empty if that does not exist.
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > Satish.
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > On Tue, Sep 1, 2020 at 9:45 AM Jun Rao < jun@
> > > confluent.
> > > > > io (
> > > > > > > > > > > > > jun@confluent.io ) > wrote:
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > >>
> > > > > > > > > > > > >>
> > > > > > > > > > > > >> Hi, Satish,
> > > > > > > > > > > > >>
> > > > > > > > > > > > >>
> > > > > > > > > > > > >>
> > > > > > > > > > > > >> Thanks for the updated KIP. Made another pass. A
> few
> > > more
> > > > > > > > comments
> > > > > > > > > > > > below.
> > > > > > > > > > > > >>
> > > > > > > > > > > > >>
> > > > > > > > > > > > >>
> > > > > > > > > > > > >> 600. The topic deletion logic needs more details.
> > > > > > > > > > > > >> 600.1 The KIP mentions "The controller considers
> the
> > > topic
> > > > > > > > > partition is
> > > > > > > > > > > > >> deleted only when it determines that there are no
> log
> > > > > segments
> > > > > > > > > for that
> > > > > > > > > > > > >> topic partition by using RLMM". How is this done?
> > > 600.2
> > > > > "If the
> > > > > > > > > delete
> > > > > > > > > > > > >> option is enabled then the leader will stop RLM
> task
> > > and
> > > > > stop
> > > > > > > > > processing
> > > > > > > > > > > > >> and it sets all the remote log segment metadata of
> > > that
> > > > > > > > partition
> > > > > > > > > with a
> > > > > > > > > > > > >> delete marker and publishes them to RLMM." We
> > > discussed
> > > > > this
> > > > > > > > > earlier.
> > > > > > > > > > > > When
> > > > > > > > > > > > >> a topic is being deleted, there may not be a
> leader
> > > for
> > > > > the
> > > > > > > > > deleted
> > > > > > > > > > > > >> partition.
> > > > > > > > > > > > >>
> > > > > > > > > > > > >>
> > > > > > > > > > > > >>
> > > > > > > > > > > > >> 601. Unclean leader election
> > > > > > > > > > > > >> 601.1 Scenario 1: new empty follower
> > > > > > > > > > > > >> After step 1, the follower restores up to offset
> 3. So
> > > > > why does
> > > > > > > > > it have
> > > > > > > > > > > > >> LE-2 <https://issues.apache.org/jira/browse/LE-2>
> at
> > > > > offset 5?
> > > > > > > > > > > > >> 601.2 senario 5: After Step 3, leader A has
> > > inconsistent
> > > > > data
> > > > > > > > > between
> > > > > > > > > > > > its
> > > > > > > > > > > > >> local and the tiered data. For example. offset 3
> has
> > > msg
> > > > > 3 LE-0
> > > > > > > > > <https://issues.apache.org/jira/browse/LE-0> locally,
> > > > > > > > > > > > >> but msg 5 LE-1 <
> > > > > https://issues.apache.org/jira/browse/LE-1> in
> > > > > > > > > the remote store. While it's ok for the unclean leader
> > > > > > > > > > > > >> to lose data, it should still return consistent
> data,
> > > > > whether
> > > > > > > > > it's from
> > > > > > > > > > > > >> the local or the remote store.
> > > > > > > > > > > > >> 601.3 The follower picks up log start offset
> using the
> > > > > following
> > > > > > > > > api.
> > > > > > > > > > > > >> Suppose that we have 3 remote segments (LE,
> > > > > SegmentStartOffset)
> > > > > > > > > as (2,
> > > > > > > > > > > > >> 10),
> > > > > > > > > > > > >> (3, 20) and (7, 15) due to an unclean leader
> election.
> > > > > Using the
> > > > > > > > > > > > following
> > > > > > > > > > > > >> api will cause logStartOffset to go backward from
> 20
> > > to
> > > > > 15. How
> > > > > > > > > do we
> > > > > > > > > > > > >> prevent that?
> > > > > > > > > > > > >> earliestLogOffset(TopicPartition topicPartition,
> int
> > > > > > > > leaderEpoch)
> > > > > > > > > 601.4
> > > > > > > > > > > > It
> > > > > > > > > > > > >> seems that retention is based on
> > > > > > > > > > > > >> listRemoteLogSegments(TopicPartition
> topicPartition,
> > > long
> > > > > > > > > leaderEpoch).
> > > > > > > > > > > > >> When there is an unclean leader election, it's
> > > possible
> > > > > for the
> > > > > > > > > new
> > > > > > > > > > > > leader
> > > > > > > > > > > > >> to not to include certain epochs in its epoch
> cache.
> > > How
> > > > > are
> > > > > > > > > remote
> > > > > > > > > > > > >> segments associated with those epochs being
> cleaned?
> > > > > 601.5 The
> > > > > > > > KIP
> > > > > > > > > > > > >> discusses the handling of unclean leader
> elections for
> > > > > user
> > > > > > > > > topics. What
> > > > > > > > > > > > >> about unclean leader elections on
> > > > > > > > > > > > >> __remote_log_segment_metadata?
> > > > > > > > > > > > >>
> > > > > > > > > > > > >>
> > > > > > > > > > > > >>
> > > > > > > > > > > > >> 602. It would be useful to clarify the
> limitations in
> > > the
> > > > > > > > initial
> > > > > > > > > > > > release.
> > > > > > > > > > > > >> The KIP mentions not supporting compacted topics.
> What
> > > > > about
> > > > > > > > JBOD
> > > > > > > > > and
> > > > > > > > > > > > >> changing the configuration of a topic from delete
> to
> > > > > compact
> > > > > > > > after
> > > > > > > > > > > > remote.
> > > > > > > > > > > > >> log. storage. enable (
> > > http://remote.log.storage.enable/
> > > > > ) is
> > > > > > > > > enabled?
> > > > > > > > > > > > >>
> > > > > > > > > > > > >>
> > > > > > > > > > > > >>
> > > > > > > > > > > > >> 603. RLM leader tasks:
> > > > > > > > > > > > >> 603.1"It checks for rolled over LogSegments (which
> > > have
> > > > > the last
> > > > > > > > > message
> > > > > > > > > > > > >> offset less than last stable offset of that topic
> > > > > partition) and
> > > > > > > > > copies
> > > > > > > > > > > > >> them along with their offset/time/transaction
> indexes
> > > and
> > > > > leader
> > > > > > > > > epoch
> > > > > > > > > > > > >> cache to the remote tier." It needs to copy the
> > > producer
> > > > > > > > snapshot
> > > > > > > > > too.
> > > > > > > > > > > > >> 603.2 "Local logs are not cleaned up till those
> > > segments
> > > > > are
> > > > > > > > > copied
> > > > > > > > > > > > >> successfully to remote even though their retention
> > > > > time/size is
> > > > > > > > > reached"
> > > > > > > > > > > > >> This seems weird. If the tiering stops because the
> > > remote
> > > > > store
> > > > > > > > > is not
> > > > > > > > > > > > >> available, we don't want the local data to grow
> > > forever.
> > > > > > > > > > > > >>
> > > > > > > > > > > > >>
> > > > > > > > > > > > >>
> > > > > > > > > > > > >> 604. "RLM maintains a bounded cache(possibly LRU)
> of
> > > the
> > > > > index
> > > > > > > > > files of
> > > > > > > > > > > > >> remote log segments to avoid multiple index
> fetches
> > > from
> > > > > the
> > > > > > > > > remote
> > > > > > > > > > > > >> storage. These indexes can be used in the same
> way as
> > > > > local
> > > > > > > > > segment
> > > > > > > > > > > > >> indexes are used." Could you provide more details
> on
> > > > > this? Are
> > > > > > > > the
> > > > > > > > > > > > indexes
> > > > > > > > > > > > >> cached in memory or on disk? If on disk, where are
> > > they
> > > > > stored?
> > > > > > > > > Are the
> > > > > > > > > > > > >> cached indexes bound by a certain size?
> > > > > > > > > > > > >>
> > > > > > > > > > > > >>
> > > > > > > > > > > > >>
> > > > > > > > > > > > >> 605. BuildingRemoteLogAux
> > > > > > > > > > > > >> 605.1 In this section, two options are listed.
> Which
> > > one
> > > > > is
> > > > > > > > > chosen?
> > > > > > > > > > > > 605.2
> > > > > > > > > > > > >> In option 2, it says "Build the local leader epoch
> > > cache
> > > > > by
> > > > > > > > > cutting the
> > > > > > > > > > > > >> leader epoch sequence received from remote
> storage to
> > > > > [LSO,
> > > > > > > > ELO].
> > > > > > > > > (LSO
> > > > > > > > > > > > >> = log start offset)." We need to do the same thing
> > > for the
> > > > > > > > > producer
> > > > > > > > > > > > >> snapshot. However, it's hard to cut the producer
> > > snapshot
> > > > > to an
> > > > > > > > > earlier
> > > > > > > > > > > > >> offset. Another option is to simply take the
> > > lastOffset
> > > > > from the
> > > > > > > > > remote
> > > > > > > > > > > > >> segment and use that as the starting fetch offset
> in
> > > the
> > > > > > > > > follower. This
> > > > > > > > > > > > >> avoids the need for cutting.
> > > > > > > > > > > > >>
> > > > > > > > > > > > >>
> > > > > > > > > > > > >>
> > > > > > > > > > > > >> 606. ListOffsets: Since we need a version bump,
> could
> > > you
> > > > > > > > > document it
> > > > > > > > > > > > >> under a protocol change section?
> > > > > > > > > > > > >>
> > > > > > > > > > > > >>
> > > > > > > > > > > > >>
> > > > > > > > > > > > >> 607. "LogStartOffset of a topic can point to
> either of
> > > > > local
> > > > > > > > > segment or
> > > > > > > > > > > > >> remote segment but it is initialised and
> maintained in
> > > > > the Log
> > > > > > > > > class
> > > > > > > > > > > > like
> > > > > > > > > > > > >> now. This is already maintained in `Log` class
> while
> > > > > loading the
> > > > > > > > > logs
> > > > > > > > > > > > and
> > > > > > > > > > > > >> it can also be fetched from
> RemoteLogMetadataManager."
> > > > > What will
> > > > > > > > > happen
> > > > > > > > > > > > to
> > > > > > > > > > > > >> the existing logic (e.g. log recovery) that
> currently
> > > > > depends on
> > > > > > > > > > > > >> logStartOffset but assumes it's local?
> > > > > > > > > > > > >>
> > > > > > > > > > > > >>
> > > > > > > > > > > > >>
> > > > > > > > > > > > >> 608. Handle expired remote segment: How does it
> pick
> > > up
> > > > > new
> > > > > > > > > > > > logStartOffset
> > > > > > > > > > > > >> from deleteRecords?
> > > > > > > > > > > > >>
> > > > > > > > > > > > >>
> > > > > > > > > > > > >>
> > > > > > > > > > > > >> 609. RLMM message format:
> > > > > > > > > > > > >> 609.1 It includes both MaxTimestamp and
> > > EventTimestamp.
> > > > > Where
> > > > > > > > > does it
> > > > > > > > > > > > get
> > > > > > > > > > > > >> both since the message in the log only contains
> one
> > > > > timestamp?
> > > > > > > > > 609.2 If
> > > > > > > > > > > > we
> > > > > > > > > > > > >> change just the state (e.g. to DELETE_STARTED), it
> > > seems
> > > > > it's
> > > > > > > > > wasteful
> > > > > > > > > > > > to
> > > > > > > > > > > > >> have to include all other fields not changed.
> 609.3
> > > Could
> > > > > you
> > > > > > > > > document
> > > > > > > > > > > > >> which process makes the following transitions
> > > > > DELETE_MARKED,
> > > > > > > > > > > > >> DELETE_STARTED, DELETE_FINISHED?
> > > > > > > > > > > > >>
> > > > > > > > > > > > >>
> > > > > > > > > > > > >>
> > > > > > > > > > > > >> 610. remote.log.reader.max.pending.tasks: "Maximum
> > > remote
> > > > > log
> > > > > > > > > reader
> > > > > > > > > > > > >> thread pool task queue size. If the task queue is
> > > full,
> > > > > broker
> > > > > > > > > will stop
> > > > > > > > > > > > >> reading remote log segments." What does the
> broker do
> > > if
> > > > > the
> > > > > > > > > queue is
> > > > > > > > > > > > >> full?
> > > > > > > > > > > > >>
> > > > > > > > > > > > >>
> > > > > > > > > > > > >>
> > > > > > > > > > > > >> 611. What do we return if the request offset/epoch
> > > > > doesn't exist
> > > > > > > > > in the
> > > > > > > > > > > > >> following API?
> > > > > > > > > > > > >> RemoteLogSegmentMetadata
> > > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > > > > >> topicPartition, long offset, int epochForOffset)
> > > > > > > > > > > > >>
> > > > > > > > > > > > >>
> > > > > > > > > > > > >>
> > > > > > > > > > > > >> Jun
> > > > > > > > > > > > >>
> > > > > > > > > > > > >>
> > > > > > > > > > > > >>
> > > > > > > > > > > > >> On Mon, Aug 31, 2020 at 11:19 AM Satish Duggana <
> > > satish.
> > > > > > > > duggana@
> > > > > > > > > > > > gmail. com
> > > > > > > > > > > > >> ( satish.duggana@gmail.com ) > wrote:
> > > > > > > > > > > > >>
> > > > > > > > > > > > >>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>> KIP is updated with
> > > > > > > > > > > > >>> - Remote log segment metadata topic message
> > > > > format/schema.
> > > > > > > > > > > > >>> - Added remote log segment metadata state
> > > transitions and
> > > > > > > > > explained how
> > > > > > > > > > > > >>> the deletion of segments is handled, including
> the
> > > case
> > > > > of
> > > > > > > > > partition
> > > > > > > > > > > > >>> deletions.
> > > > > > > > > > > > >>> - Added a few more limitations in the "Non goals"
> > > > > section.
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>> Thanks,
> > > > > > > > > > > > >>> Satish.
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>> On Thu, Aug 27, 2020 at 12:42 AM Harsha Ch <
> harsha.
> > > ch@
> > > > > > > > gmail.
> > > > > > > > > com (
> > > > > > > > > > > > >>> harsha.ch@gmail.com ) > wrote:
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>> Updated the KIP with Meeting Notes section
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>> https:/ / cwiki. apache. org/ confluence/
> display/
> > > KAFKA/
> > > > > > > > > > > > KIP-405 <
> https://issues.apache.org/jira/browse/KIP-405>
> > > > > > > > >
> %3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> > > > > > > > > > > > >>> (
> > > > > > > > > > > > >>>
> > > > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > >
> > >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-405%3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> > > > > > > > > > > > >>> )
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>> On Tue, Aug 25, 2020 at 1:03 PM Jun Rao < jun@
> > > > > confluent. io
> > > > > > > > (
> > > > > > > > > > > > >>>> jun@confluent.io ) > wrote:
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>> Hi, Harsha,
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>> Thanks for the summary. Could you add the
> summary
> > > and
> > > > > the
> > > > > > > > > recording
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>> link to
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>> the last section of
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>> https:/ / cwiki. apache. org/ confluence/
> display/
> > > KAFKA/
> > > > > > > > > > > > Kafka+Improvement+Proposals
> > > > > > > > > > > > >>> (
> > > > > > > > > > > > >>>
> > > > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > >
> > >
> https://cwiki.apache.org/confluence/display/KAFKA/Kafka+Improvement+Proposals
> > > > > > > > > > > > >>> )
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>> ?
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>> Jun
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>> On Tue, Aug 25, 2020 at 11:12 AM Harsha
> > > Chintalapani <
> > > > > kafka@
> > > > > > > > > > > > harsha. io (
> > > > > > > > > > > > >>>>> kafka@harsha.io ) > wrote:
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>> Thanks everyone for attending the meeting
> today.
> > > > > > > > > > > > >>>>>> Here is the recording
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>> https:/ / drive. google. com/ file/ d/
> > > > > > > > > > > > 14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/ view?usp=sharing
> > > > > > > > > > > > >>> (
> > > > > > > > > > > > >>>
> > > > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > >
> > >
> https://drive.google.com/file/d/14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/view?usp=sharing
> > > > > > > > > > > > >>> )
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>> Notes:
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>> 1. KIP is updated with follower fetch
> protocol and
> > > > > ready to
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>> reviewed
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>> 2. Satish to capture schema of internal
> metadata
> > > > > topic in
> > > > > > > > the
> > > > > > > > > KIP
> > > > > > > > > > > > >>>>>> 3. We will update the KIP with details of
> > > different
> > > > > cases
> > > > > > > > > > > > >>>>>> 4. Test plan will be captured in a doc and
> will
> > > add
> > > > > to the
> > > > > > > > KIP
> > > > > > > > > > > > >>>>>> 5. Add a section "Limitations" to capture the
> > > > > capabilities
> > > > > > > > > that
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>> will
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>> be
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>> introduced with this KIP and what will not be
> > > covered
> > > > > in
> > > > > > > > this
> > > > > > > > > KIP.
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>> Please add to it I missed anything. Will
> produce a
> > > > > formal
> > > > > > > > > meeting
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>> notes
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>> from next meeting onwards.
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>> Thanks,
> > > > > > > > > > > > >>>>>> Harsha
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>> On Mon, Aug 24, 2020 at 9:42 PM, Ying Zheng <
> > > yingz@
> > > > > uber.
> > > > > > > > > com.
> > > > > > > > > > > > invalid (
> > > > > > > > > > > > >>>>>> yingz@uber.com.invalid ) > wrote:
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> We did some basic feature tests at Uber. The
> test
> > > > > cases and
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>> results are
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> shared in this google doc:
> > > > > > > > > > > > >>>>>>> https:/ / docs. google. com/ spreadsheets/
> d/ (
> > > > > > > > > > > > >>>>>>> https://docs.google.com/spreadsheets/d/ )
> > > > > > > > > > > > >>>>>>>
> > > > > > > > 1XhNJqjzwXvMCcAOhEH0sSXU6RTvyoSf93DHF-YMfGLk/edit?usp=sharing
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> The performance test results were already
> shared
> > > in
> > > > > the KIP
> > > > > > > > > last
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>> month.
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> On Mon, Aug 24, 2020 at 11:10 AM Harsha Ch <
> > > harsha.
> > > > > ch@
> > > > > > > > > gmail.
> > > > > > > > > > > > com (
> > > > > > > > > > > > >>>>>>> harsha.ch@gmail.com ) >
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>> wrote:
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> "Understand commitments towards driving
> design &
> > > > > > > > > implementation of
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>> the
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>> KIP
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> further and how it aligns with participant
> > > interests
> > > > > in
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>> contributing to
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>> the
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> efforts (ex: in the context of Uber’s Q3/Q4
> > > > > roadmap)." What
> > > > > > > > > is that
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>> about?
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> On Mon, Aug 24, 2020 at 11:05 AM Kowshik
> > > Prakasam <
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>> kprakasam@ confluent. io (
> kprakasam@confluent.io
> > > ) >
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> wrote:
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> Hi Harsha,
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> The following google doc contains a proposal
> for
> > > > > temporary
> > > > > > > > > agenda
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>> for
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>> the
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> KIP-405 <
> > > > > https://issues.apache.org/jira/browse/KIP-405> <
> > > > > > > > > https:/ / issues. apache. org/ jira/ browse/ KIP-405
> > > > > > > > > <https://issues.apache.org/jira/browse/KIP-405> (
> > > > > > > > > > > > >>>>>>>
> https://issues.apache.org/jira/browse/KIP-405 )
> > > >
> > > > > sync
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>> meeting
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> tomorrow:
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> https:/ / docs. google. com/ document/ d/ (
> > > > > > > > > > > > >>>>>>> https://docs.google.com/document/d/ )
> > > > > > > > > > > > >>>>>>>
> 1pqo8X5LU8TpwfC_iqSuVPezhfCfhGkbGN2TqiPA3LBU/edit
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> .
> > > > > > > > > > > > >>>>>>> Please could you add it to the Google
> calendar
> > > > > invite?
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> Thank you.
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> Cheers,
> > > > > > > > > > > > >>>>>>> Kowshik
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> On Thu, Aug 20, 2020 at 10:58 AM Harsha Ch <
> > > harsha.
> > > > > ch@
> > > > > > > > > gmail.
> > > > > > > > > > > > com (
> > > > > > > > > > > > >>>>>>> harsha.ch@gmail.com ) >
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>> wrote:
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> Hi All,
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> Scheduled a meeting for Tuesday 9am - 10am.
> I can
> > > > > record
> > > > > > > > and
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>> upload for
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> community to be able to follow the
> discussion.
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> Jun, please add the required folks on
> confluent
> > > side.
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> Thanks,
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> Harsha
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> On Thu, Aug 20, 2020 at 12:33 AM, Alexandre
> > > Dupriez <
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>> alexandre.dupriez@
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> gmail. com ( http://gmail.com/ ) > wrote:
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> Hi Jun,
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> Many thanks for your initiative.
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> If you like, I am happy to attend at the
> time you
> > > > > > > > suggested.
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> Many thanks,
> > > > > > > > > > > > >>>>>>> Alexandre
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> Le mer. 19 août 2020 à 22:00, Harsha Ch <
> > > harsha. ch@
> > > > > > > > > gmail. com (
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>> harsha.
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> ch@ gmail. com ( ch@gmail.com ) ) > a écrit
> :
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> Hi Jun,
> > > > > > > > > > > > >>>>>>> Thanks. This will help a lot. Tuesday will
> work
> > > for
> > > > > us.
> > > > > > > > > > > > >>>>>>> -Harsha
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> On Wed, Aug 19, 2020 at 1:24 PM Jun Rao <
> jun@
> > > > > confluent.
> > > > > > > > > io (
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>> jun@
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> confluent. io ( http://confluent.io/ ) ) >
> > > wrote:
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> Hi, Satish, Ying, Harsha,
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> Do you think it would be useful to have a
> regular
> > > > > virtual
> > > > > > > > > meeting
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>> to
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>
> > > > > > > > > > > > >>>>
> > > > > > > > > > > > >>>>>
> > > > > > > > > > > > >>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> discuss this KIP? The goal of the meeting
> will be
> > > > > sharing
> > > > > > > > > > > > >>>>>>> design/development progress and discussing
> any
> > > open
> > > > > issues
> > > > > > > > to
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> accelerate
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> this KIP. If so, will every Tuesday (from
> next
> > > week)
> > > > > > > > 9am-10am
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> PT
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> work for you? I can help set up a Zoom
> meeting,
> > > > > invite
> > > > > > > > > everyone who
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> might
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> be interested, have it recorded and shared,
> etc.
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> Thanks,
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> Jun
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> On Tue, Aug 18, 2020 at 11:01 AM Satish
> Duggana <
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> satish. duggana@ gmail. com ( satish.
> duggana@
> > > > > gmail. com
> > > > > > > > (
> > > > > > > > > > > > >>>>>>> satish.duggana@gmail.com ) ) >
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> wrote:
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> Hi Kowshik,
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> Thanks for looking into the KIP and sending
> your
> > > > > comments.
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>>
> > > > > > > > > > > > >>>>>>> 5001. Under the section "Follower fetch
> protocol
> > > in
> > > > > > > > detail",
> > > > > > > > > the
> > > > > > > > > > > > >>>>>>> next-local-offset is the offset upto which
> the
> > > > > segments are
> > > > > > > > > copied
> > > > > > > > > > > > >>>>>>>
> > > > > > > > >
> > > > >
> > > > >
> > >
>

Re: [DISCUSS] KIP-405: Kafka Tiered Storage

[Satish Duggana <sa...@gmail.com>]

Hi Jun,
Thanks for your comments. Please go through the inline replies.


5102.2: It seems that both positions can just be int. Another option is to
have two methods. Would it be clearer?

    InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
remoteLogSegmentMetadata,  int startPosition) throwsRemoteStorageException;

    InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
remoteLogSegmentMetadata, int startPosition, int endPosition) throws
RemoteStorageException;

That makes sense to me, updated the KIP.

6003: Could you also update the javadoc for the return value?

Updated.

6020: local.log.retention.bytes: Should it default to log.retention.bytes
to be consistent with local.log.retention.ms?

Yes, it can be defaulted to log.retention.bytes.

6021: Could you define TopicIdPartition?

Added TopicIdPartition in the KIP.

6022: For all public facing classes, could you specify the package name?

Updated.


Thanks,
Satish.

On Tue, Dec 8, 2020 at 12:59 AM Jun Rao <ju...@confluent.io> wrote:
>
> Hi, Satish,
>
> Thanks for the reply. A few more comments below.
>
> 5102.2: It seems that both positions can just be int. Another option is to
> have two methods. Would it be clearer?
>
>     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> remoteLogSegmentMetadata,
>                                     int startPosition) throws
> RemoteStorageException;
>
>     InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
> remoteLogSegmentMetadata,
>                                     int startPosition, int endPosition)
> throws RemoteStorageException;
>
> 6003: Could you also update the javadoc for the return value?
>
> 6010: What kind of tiering throughput have you seen with 5 threads?
>
> 6020: local.log.retention.bytes: Should it default to log.retention.bytes
> to be consistent with local.log.retention.ms?
>
> 6021: Could you define TopicIdPartition?
>
> 6022: For all public facing classes, could you specify the package name?
>
> It seems that you already added the topicId support. Two other remaining
> items are (a) the format of local tier metadata storage and (b) upgrade.
>
> Jun
>
> On Mon, Dec 7, 2020 at 8:56 AM Satish Duggana <sa...@gmail.com>
> wrote:
>
> > Hi Jun,
> > Thanks for your comments. Please find the inline replies below.
> >
> > >605.2 It's rare for the follower to need the remote data. So, the current
> > approach is fine too. Could you document the process of rebuilding the
> > producer state since we can't simply trim the producerState to an offset in
> > the middle of a segment.
> >
> > Will clarify in the KIP.
> >
> > >5102.2 Would it be clearer to make startPosiont long and endPosition of
> > Optional<Long>?
> >
> > We will have arg checks with respective validation. It is not a good
> > practice to have arguments with optional as mentioned here.
> > https://rules.sonarsource.com/java/RSPEC-3553
> >
> >
> > >5102.5 LogSegmentData still has leaderEpochIndex as File instead of
> > ByteBuffer.
> >
> > Updated.
> >
> > >5102.7 Could you define all public methods for LogSegmentData?
> >
> > Updated.
> >
> > >5103.5 Could you change the reference to rlm_process_interval_ms and
> > rlm_retry_interval_ms to the new config names? Also, the retry interval
> > config seems still missing. It would be useful to support exponential
> > backoff with the retry interval config.
> >
> > Good point. We wanted the retry with truncated exponential backoff,
> > updated the KIP.
> >
> > >5111. "RLM follower fetches the earliest offset for the earliest leader
> > epoch by calling RLMM.earliestLogOffset(TopicPartition topicPartition, int
> > leaderEpoch) and updates that as the log start offset." This text is still
> > there. Also, could we remove earliestLogOffset() from RLMM?
> >
> > Updated.
> >
> > >5115. There are still references to "remote log cleaners".
> >
> > Updated.
> >
> > >6000. Since we are returning new error codes, we need to bump up the
> > protocol version for Fetch request. Also, it will be useful to document all
> > new error codes and whether they are retriable or not.
> >
> > Sure, we will add that in the KIP.
> >
> > >6001. public Map<Long, Long> segmentLeaderEpochs(): Currently, leaderEpoch
> > is int32 instead of long.
> >
> > Updated.
> >
> > >6002. Is RemoteLogSegmentMetadata.markedForDeletion() needed given
> > RemoteLogSegmentMetadata.state()?
> >
> > No, it is fixed.
> >
> > >6003. RemoteLogSegmentMetadata remoteLogSegmentMetadata(TopicPartition
> > topicPartition, long offset, int epochForOffset): Should this return
> > Optional<RemoteLogSegmentMetadata>?
> >
> > That makes sense, updated.
> >
> > >6005. RemoteLogState: It seems it's better to split it between
> > DeletePartitionUpdate and RemoteLogSegmentMetadataUpdate since the states
> > are never shared between the two use cases.
> >
> > Agree with that, updated.
> >
> > >6006. RLMM.onPartitionLeadershipChanges(): This may be ok. However, is it
> > ture that other than the metadata topic, RLMM just needs to know whether
> > there is a replica assigned to this broker and doesn't need to know whether
> > the replica is the leader or the follower?
> >
> > That may be true. If the implementation does not need that, it can
> > ignore the information in the callback.
> >
> > >6007: "Handle expired remote segments (leader and follower)": Why is this
> > needed in both the leader and the follower?
> >
> > Updated.
> >
> > >6008.       "name": "SegmentSizeInBytes",
> >                 "type": "int64",
> > The segment size can just be int32.
> >
> > Updated.
> >
> > >6009. For the record format in the log, it seems that we need to add
> > record
> > type and record version before the serialized bytes. We can follow the
> > convention used in
> >
> > https://cwiki.apache.org/confluence/display/KAFKA/KIP-631%3A+The+Quorum-based+Kafka+Controller#KIP631:TheQuorumbasedKafkaController-RecordFormats
> >
> > Yes, KIP already mentions that these are serialized before the payload
> > as below. We will mention explicitly that these two are written before
> > the data is written.
> >
> > RLMM instance on broker publishes the message to the topic with key as
> > null and value with the below format.
> >
> > type      : unsigned var int, represents the value type. This value is
> > 'apikey' as mentioned in the schema.
> > version : unsigned var int, the 'version' number of the type as
> > mentioned in the schema.
> > data      : record payload in kafka protocol message format.
> >
> >
> > >6010. remote.log.manager.thread.pool.size: The default value is 10. This
> > might be too high when enabling the tiered feature for the first time.
> > Since there are lots of segments that need to be tiered initially, a large
> > number of threads could overwhelm the broker.
> >
> > Is the default value 5 reasonable?
> >
> > 6011. "The number of milli seconds to keep the local log segment before it
> > gets deleted. If not set, the value in `log.retention.minutes` is used. If
> > set to -1, no time limit is applied." We should use log.retention.ms
> > instead of log.retention.minutes.
> > Nice typo catch. Updated the KIP.
> >
> > Thanks,
> > Satish.
> >
> > On Thu, Dec 3, 2020 at 8:03 AM Jun Rao <ju...@confluent.io> wrote:
> > >
> > > Hi, Satish,
> > >
> > > Thanks for the updated KIP. A few more comments below.
> > >
> > > 605.2 It's rare for the follower to need the remote data. So, the current
> > > approach is fine too. Could you document the process of rebuilding the
> > > producer state since we can't simply trim the producerState to an offset
> > in
> > > the middle of a segment.
> > >
> > > 5102.2 Would it be clearer to make startPosiont long and endPosition of
> > > Optional<Long>?
> > >
> > > 5102.5 LogSegmentData still has leaderEpochIndex as File instead of
> > > ByteBuffer.
> > >
> > > 5102.7 Could you define all public methods for LogSegmentData?
> > >
> > > 5103.5 Could you change the reference to rlm_process_interval_ms and
> > > rlm_retry_interval_ms to the new config names? Also, the retry interval
> > > config seems still missing. It would be useful to support exponential
> > > backoff with the retry interval config.
> > >
> > > 5111. "RLM follower fetches the earliest offset for the earliest leader
> > > epoch by calling RLMM.earliestLogOffset(TopicPartition topicPartition,
> > int
> > > leaderEpoch) and updates that as the log start offset." This text is
> > still
> > > there. Also, could we remove earliestLogOffset() from RLMM?
> > >
> > > 5115. There are still references to "remote log cleaners".
> > >
> > > 6000. Since we are returning new error codes, we need to bump up the
> > > protocol version for Fetch request. Also, it will be useful to document
> > all
> > > new error codes and whether they are retriable or not.
> > >
> > > 6001. public Map<Long, Long> segmentLeaderEpochs(): Currently,
> > leaderEpoch
> > > is int32 instead of long.
> > >
> > > 6002. Is RemoteLogSegmentMetadata.markedForDeletion() needed given
> > > RemoteLogSegmentMetadata.state()?
> > >
> > > 6003. RemoteLogSegmentMetadata remoteLogSegmentMetadata(TopicPartition
> > > topicPartition, long offset, int epochForOffset): Should this return
> > > Optional<RemoteLogSegmentMetadata>?
> > >
> > > 6004. DeletePartitionUpdate.epoch(): It would be useful to pick a more
> > > indicative name so that people understand what epoch this is.
> > >
> > > 6005. RemoteLogState: It seems it's better to split it between
> > > DeletePartitionUpdate and RemoteLogSegmentMetadataUpdate since the states
> > > are never shared between the two use cases.
> > >
> > > 6006. RLMM.onPartitionLeadershipChanges(): This may be ok. However, is it
> > > ture that other than the metadata topic, RLMM just needs to know whether
> > > there is a replica assigned to this broker and doesn't need to know
> > whether
> > > the replica is the leader or the follower?
> > >
> > > 6007: "Handle expired remote segments (leader and follower)": Why is this
> > > needed in both the leader and the follower?
> > >
> > > 6008.       "name": "SegmentSizeInBytes",
> > >                 "type": "int64",
> > > The segment size can just be int32.
> > >
> > > 6009. For the record format in the log, it seems that we need to add
> > record
> > > type and record version before the serialized bytes. We can follow the
> > > convention used in
> > >
> > https://cwiki.apache.org/confluence/display/KAFKA/KIP-631%3A+The+Quorum-based+Kafka+Controller#KIP631:TheQuorumbasedKafkaController-RecordFormats
> > > .
> > >
> > > 6010. remote.log.manager.thread.pool.size: The default value is 10. This
> > > might be too high when enabling the tiered feature for the first time.
> > > Since there are lots of segments that need to be tiered initially, a
> > large
> > > number of threads could overwhelm the broker.
> > >
> > > 6011. "The number of milli seconds to keep the local log segment before
> > it
> > > gets deleted. If not set, the value in `log.retention.minutes` is used.
> > If
> > > set to -1, no time limit is applied." We should use log.retention.ms
> > > instead of log.retention.minutes.
> > >
> > > Jun
> > >
> > > On Tue, Dec 1, 2020 at 2:42 AM Satish Duggana <sa...@gmail.com>
> > > wrote:
> > >
> > > > Hi,
> > > > We updated the KIP with the points mentioned in the earlier mail
> > > > except for KIP-516 related changes. You can go through them and let us
> > > > know if you have any comments. We will update the KIP with the
> > > > remaining todo items and KIP-516 related changes by end of this
> > > > week(5th Dec).
> > > >
> > > > Thanks,
> > > > Satish.
> > > >
> > > > On Tue, Nov 10, 2020 at 8:26 PM Satish Duggana <
> > satish.duggana@gmail.com>
> > > > wrote:
> > > > >
> > > > > Hi Jun,
> > > > > Thanks for your comments. Please find the inline replies below.
> > > > >
> > > > > 605.2 "Build the local leader epoch cache by cutting the leader epoch
> > > > > sequence received from remote storage to [LSO, ELO]." I mentioned an
> > > > issue
> > > > > earlier. Suppose the leader's local start offset is 100. The follower
> > > > finds
> > > > > a remote segment covering offset range [80, 120). The producerState
> > with
> > > > > this remote segment is up to offset 120. To trim the producerState to
> > > > > offset 100 requires more work since one needs to download the
> > previous
> > > > > producerState up to offset 80 and then replay the messages from 80 to
> > > > 100.
> > > > > It seems that it's simpler in this case for the follower just to
> > take the
> > > > > remote segment as it is and start fetching from offset 120.
> > > > >
> > > > > We chose that approach to avoid any edge cases here. It may be
> > > > > possible that the remote log segment that is received may not have
> > the
> > > > > same leader epoch sequence from 100-120 as it contains on the
> > > > > leader(this can happen due to unclean leader). It is safe to start
> > > > > from what the leader returns here.Another way is to find the remote
> > > > > log segment
> > > > >
> > > > > 5016. Just to echo what Kowshik was saying. It seems that
> > > > > RLMM.onPartitionLeadershipChanges() is only called on the replicas
> > for a
> > > > > partition, not on the replicas for the __remote_log_segment_metadata
> > > > > partition. It's not clear how the leader of
> > __remote_log_segment_metadata
> > > > > obtains the metadata for remote segments for deletion.
> > > > >
> > > > > RLMM will always receive the callback for the remote log metadata
> > > > > topic partitions hosted on the local broker and these will be
> > > > > subscribed. I will make this clear in the KIP.
> > > > >
> > > > > 5100. KIP-516 has been accepted and is being implemented now. Could
> > you
> > > > > update the KIP based on topicID?
> > > > >
> > > > > We mentioned KIP-516 and how it helps. We will update this KIP with
> > > > > all the changes it brings with KIP-516.
> > > > >
> > > > > 5101. RLMM: It would be useful to clarify how the following two APIs
> > are
> > > > > used. According to the wiki, the former is used for topic deletion
> > and
> > > > the
> > > > > latter is used for retention. It seems that retention should use the
> > > > former
> > > > > since remote segments without a matching epoch in the leader
> > (potentially
> > > > > due to unclean leader election) also need to be garbage collected.
> > The
> > > > > latter seems to be used for the new leader to determine the last
> > tiered
> > > > > segment.
> > > > >     default Iterator<RemoteLogSegmentMetadata>
> > > > > listRemoteLogSegments(TopicPartition topicPartition)
> > > > >     Iterator<RemoteLogSegmentMetadata>
> > > > listRemoteLogSegments(TopicPartition
> > > > > topicPartition, long leaderEpoch);
> > > > >
> > > > > Right,.that is what we are currently doing. We will update the
> > > > > javadocs and wiki with that. Earlier, we did not want to remove the
> > > > > segments which are not matched with leader epochs from the ladder
> > > > > partition as they may be used later by a replica which can become a
> > > > > leader (unclean leader election) and refer those segments. But that
> > > > > may leak these segments in remote storage until the topic lifetime.
> > We
> > > > > decided to cleanup the segments with the oldest incase of size based
> > > > > retention also.
> > > > >
> > > > > 5102. RSM:
> > > > > 5102.1 For methods like fetchLogSegmentData(), it seems that they can
> > > > > use RemoteLogSegmentId instead of RemoteLogSegmentMetadata.
> > > > >
> > > > > It will be useful to have metadata for RSM to fetch log segment. It
> > > > > may create location/path using id with other metadata too.
> > > > >
> > > > > 5102.2 In fetchLogSegmentData(), should we use long instead of Long?
> > > > >
> > > > > Wanted to keep endPosition as optional to read till the end of the
> > > > > segment and avoid sentinels.
> > > > >
> > > > > 5102.3 Why only some of the methods have default implementation and
> > > > others
> > > > > Don't?
> > > > >
> > > > > Actually,  RSM will not have any default implementations. Those 3
> > > > > methods were made default earlier for tests etc. Updated the wiki.
> > > > >
> > > > > 5102.4. Could we define RemoteLogSegmentMetadataUpdate
> > > > > and DeletePartitionUpdate?
> > > > >
> > > > > Sure, they will be added.
> > > > >
> > > > >
> > > > > 5102.5 LogSegmentData: It seems that it's easier to pass
> > > > > in leaderEpochIndex as a ByteBuffer or byte array than a file since
> > it
> > > > will
> > > > > be generated in memory.
> > > > >
> > > > > Right, this is in plan.
> > > > >
> > > > > 5102.6 RemoteLogSegmentMetadata: It seems that it needs both
> > baseOffset
> > > > and
> > > > > startOffset. For example, deleteRecords() could move the startOffset
> > to
> > > > the
> > > > > middle of a segment. If we copy the full segment to remote storage,
> > the
> > > > > baseOffset and the startOffset will be different.
> > > > >
> > > > > Good point. startOffset is baseOffset by default, if not set
> > explicitly.
> > > > >
> > > > > 5102.7 Could we define all the public methods for
> > > > RemoteLogSegmentMetadata
> > > > > and LogSegmentData?
> > > > >
> > > > > Sure, updated the wiki.
> > > > >
> > > > > 5102.8 Could we document whether endOffset in
> > RemoteLogSegmentMetadata is
> > > > > inclusive/exclusive?
> > > > >
> > > > > It is inclusive, will update.
> > > > >
> > > > > 5103. configs:
> > > > > 5103.1 Could we define the default value of non-required configs
> > (e.g the
> > > > > size of new thread pools)?
> > > > >
> > > > > Sure, that makes sense.
> > > > >
> > > > > 5103.2 It seems that local.log.retention.ms should default to
> > > > retention.ms,
> > > > > instead of remote.log.retention.minutes. Similarly, it seems
> > > > > that local.log.retention.bytes should default to segment.bytes.
> > > > >
> > > > > Right, we do not have  remote.log.retention as we discussed earlier.
> > > > > Thanks for catching the typo.
> > > > >
> > > > > 5103.3 remote.log.manager.thread.pool.size: The description says
> > "used in
> > > > > scheduling tasks to copy segments, fetch remote log indexes and
> > clean up
> > > > > remote log segments". However, there is a separate
> > > > > config remote.log.reader.threads for fetching remote data. It's
> > weird to
> > > > > fetch remote index and log in different thread pools since both are
> > used
> > > > > for serving fetch requests.
> > > > >
> > > > > Right, remote.log.manager.thread.pool is mainly used for copy/cleanup
> > > > > activities. Fetch path always goes through remote.log.reader.threads.
> > > > >
> > > > > 5103.4 remote.log.manager.task.interval.ms: Is that the amount of
> > time
> > > > to
> > > > > back off when there is no work to do? If so, perhaps it can be
> > renamed as
> > > > > backoff.ms.
> > > > >
> > > > > This is the delay interval for each iteration. It may be renamed to
> > > > > remote.log.manager.task.delay.ms
> > > > >
> > > > > 5103.5 Are rlm_process_interval_ms and rlm_retry_interval_ms
> > configs? If
> > > > > so, they need to be listed in this section.
> > > > >
> > > > > remote.log.manager.task.interval.ms is the process internal, retry
> > > > > interval is missing in the configs, which will be updated in the KIP.
> > > > >
> > > > > 5104. "RLM maintains a bounded cache(possibly LRU) of the index
> > files of
> > > > > remote log segments to avoid multiple index fetches from the remote
> > > > > storage." Is the RLM in memory or on disk? If on disk, where is it
> > > > stored?
> > > > > Do we need a configuration to bound the size?
> > > > >
> > > > > It is stored on disk. They are stored in a directory
> > > > > `remote-log-index-cache` under log dir. We plan to have a config for
> > > > > that instead of default. We will have a configuration for that.
> > > > >
> > > > > 5105. The KIP uses local-log-start-offset and Earliest Local Offset
> > in
> > > > > different places. It would be useful to standardize the terminology.
> > > > >
> > > > > Sure.
> > > > >
> > > > > 5106. The section on "In BuildingRemoteLogAux state". It listed two
> > > > options
> > > > > without saying which option is chosen.
> > > > > We already mentioned in the KIP that we chose option-2.
> > > > >
> > > > > 5107. Follower to leader transition: It has step 2, but not step 1.
> > > > > Step-1 is there but it is not explicitly highlighted. It is previous
> > > > > table to step-2.
> > > > >
> > > > > 5108. If a consumer fetches from the remote data and the remote
> > storage
> > > > is
> > > > > not available, what error code is used in the fetch response?
> > > > >
> > > > > Good point. We have not yet defined the error for this case. We need
> > > > > to define an error message and send the same in fetch response.
> > > > >
> > > > > 5109. "ListOffsets: For timestamps >= 0, it returns the first message
> > > > > offset whose timestamp is >= to the given timestamp in the request.
> > That
> > > > > means it checks in remote log time indexes first, after which local
> > log
> > > > > time indexes are checked." Could you document which method in RLMM is
> > > > used
> > > > > for this?
> > > > >
> > > > > Okay.
> > > > >
> > > > > 5110. Stopreplica: "it sets all the remote log segment metadata of
> > that
> > > > > partition with a delete marker and publishes them to RLMM." This
> > seems
> > > > > outdated given the new topic deletion logic.
> > > > >
> > > > > Will update with KIP-516 related points.
> > > > >
> > > > > 5111. "RLM follower fetches the earliest offset for the earliest
> > leader
> > > > > epoch by calling RLMM.earliestLogOffset(TopicPartition
> > topicPartition,
> > > > int
> > > > > leaderEpoch) and updates that as the log start offset." Do we need
> > that
> > > > > since replication propagates logStartOffset already?
> > > > >
> > > > > Good point. Right, existing replication protocol takes care of
> > > > > updating the followers’s log start offset received from the leader.
> > > > >
> > > > > 5112. Is the default maxWaitMs of 500ms enough for fetching from
> > remote
> > > > > storage?
> > > > >
> > > > > Remote reads may fail within the current default wait time, but
> > > > > subsequent fetches would be able to serve as that data is stored in
> > > > > the local cache. This cache is currently implemented in RSMs. But we
> > > > > plan to pull this into the remote log messaging layer in future.
> > > > >
> > > > > 5113. "Committed offsets can be stored in a local file to avoid
> > reading
> > > > the
> > > > > messages again when a broker is restarted." Could you describe the
> > format
> > > > > and the location of the file? Also, could the same message be
> > processed
> > > > by
> > > > > RLMM again after broker restart? If so, how do we handle that?
> > > > >
> > > > > Sure, we will update in the KIP.
> > > > >
> > > > > 5114. Message format
> > > > > 5114.1 There are two records named RemoteLogSegmentMetadataRecord
> > with
> > > > > apiKey 0 and 1.
> > > > >
> > > > > Nice catch, that was a typo. Fixed in the wiki.
> > > > >
> > > > > 5114.2 RemoteLogSegmentMetadataRecord: Could we document whether
> > > > endOffset
> > > > > is inclusive/exclusive?
> > > > > It is inclusive, will update.
> > > > >
> > > > > 5114.3 RemoteLogSegmentMetadataRecord: Could you explain LeaderEpoch
> > a
> > > > bit
> > > > > more? Is that the epoch of the leader when it copies the segment to
> > > > remote
> > > > > storage? Also, how will this field be used?
> > > > >
> > > > > Right, this is the leader epoch of the broker which copied this
> > > > > segment. This is helpful in reason about which broker copied the
> > > > > segment to remote storage.
> > > > >
> > > > > 5114.4 EventTimestamp: Could you explain this a bit more? Each
> > record in
> > > > > Kafka already has a timestamp field. Could we just use that?
> > > > >
> > > > > This is the  timestamp at which  the respective event occurred. Added
> > > > > this  to RemoteLogSegmentMetadata as RLMM can be  any other
> > > > > implementation. We thought about that but it looked cleaner to use at
> > > > > the message structure level instead of getting that from the consumer
> > > > > record and using that to build the respective event.
> > > > >
> > > > >
> > > > > 5114.5 SegmentSizeInBytes: Could this just be int32?
> > > > >
> > > > > Right, it looks like config allows only int value >= 14.
> > > > >
> > > > > 5115. RemoteLogCleaner(RLC): This could be confused with the log
> > cleaner
> > > > > for compaction. Perhaps it can be renamed to sth like
> > > > > RemotePartitionRemover.
> > > > >
> > > > > I am fine with RemotePartitionRemover or RemoteLogDeletionManager(we
> > > > > have other manager classes like RLM, RLMM).
> > > > >
> > > > > 5116. "RLC receives the delete_partition_marked and processes it if
> > it is
> > > > > not yet processed earlier." How does it know whether
> > > > > delete_partition_marked has been processed earlier?
> > > > >
> > > > > This is to handle duplicate delete_partition_marked events. RLC
> > > > > internally maintains a state for the delete_partition events and if
> > it
> > > > > already has an existing event then it ignores if it is already being
> > > > > processed.
> > > > >
> > > > > 5117. Should we add a new MessageFormatter to read the tier metadata
> > > > topic?
> > > > >
> > > > > Right, this is in plan but did not mention it in the KIP. This will
> > be
> > > > > useful for debugging purposes too.
> > > > >
> > > > > 5118. "Maximum remote log reader thread pool task queue size. If the
> > task
> > > > > queue is full, broker will stop reading remote log segments." What
> > do we
> > > > > return to the fetch request in this case?
> > > > >
> > > > > We return an error response for that partition.
> > > > >
> > > > > 5119. It would be useful to list all things not supported in the
> > first
> > > > > version in a Future work or Limitations section. For example,
> > compacted
> > > > > topic, JBOD, changing remote.log.storage.enable from true to false,
> > etc.
> > > > >
> > > > > We already have a non-goals section which is filled with some of
> > these
> > > > > details. Do we need another limitations section?
> > > > >
> > > > > Thanks,
> > > > > Satish.
> > > > >
> > > > > On Wed, Nov 4, 2020 at 11:27 PM Jun Rao <ju...@confluent.io> wrote:
> > > > > >
> > > > > > Hi, Satish,
> > > > > >
> > > > > > Thanks for the updated KIP. A few more comments below.
> > > > > >
> > > > > > 605.2 "Build the local leader epoch cache by cutting the leader
> > epoch
> > > > > > sequence received from remote storage to [LSO, ELO]." I mentioned
> > an
> > > > issue
> > > > > > earlier. Suppose the leader's local start offset is 100. The
> > follower
> > > > finds
> > > > > > a remote segment covering offset range [80, 120). The producerState
> > > > with
> > > > > > this remote segment is up to offset 120. To trim the producerState
> > to
> > > > > > offset 100 requires more work since one needs to download the
> > previous
> > > > > > producerState up to offset 80 and then replay the messages from 80
> > to
> > > > 100.
> > > > > > It seems that it's simpler in this case for the follower just to
> > take
> > > > the
> > > > > > remote segment as it is and start fetching from offset 120.
> > > > > >
> > > > > > 5016. Just to echo what Kowshik was saying. It seems that
> > > > > > RLMM.onPartitionLeadershipChanges() is only called on the replicas
> > for
> > > > a
> > > > > > partition, not on the replicas for the
> > __remote_log_segment_metadata
> > > > > > partition. It's not clear how the leader of
> > > > __remote_log_segment_metadata
> > > > > > obtains the metadata for remote segments for deletion.
> > > > > >
> > > > > > 5100. KIP-516 has been accepted and is being implemented now.
> > Could you
> > > > > > update the KIP based on topicID?
> > > > > >
> > > > > > 5101. RLMM: It would be useful to clarify how the following two
> > APIs
> > > > are
> > > > > > used. According to the wiki, the former is used for topic deletion
> > and
> > > > the
> > > > > > latter is used for retention. It seems that retention should use
> > the
> > > > former
> > > > > > since remote segments without a matching epoch in the leader
> > > > (potentially
> > > > > > due to unclean leader election) also need to be garbage collected.
> > The
> > > > > > latter seems to be used for the new leader to determine the last
> > tiered
> > > > > > segment.
> > > > > >     default Iterator<RemoteLogSegmentMetadata>
> > > > > > listRemoteLogSegments(TopicPartition topicPartition)
> > > > > >     Iterator<RemoteLogSegmentMetadata>
> > > > listRemoteLogSegments(TopicPartition
> > > > > > topicPartition, long leaderEpoch);
> > > > > >
> > > > > > 5102. RSM:
> > > > > > 5102.1 For methods like fetchLogSegmentData(), it seems that they
> > can
> > > > > > use RemoteLogSegmentId instead of RemoteLogSegmentMetadata.
> > > > > > 5102.2 In fetchLogSegmentData(), should we use long instead of
> > Long?
> > > > > > 5102.3 Why only some of the methods have default implementation and
> > > > others
> > > > > > don't?
> > > > > > 5102.4. Could we define RemoteLogSegmentMetadataUpdate
> > > > > > and DeletePartitionUpdate?
> > > > > > 5102.5 LogSegmentData: It seems that it's easier to pass
> > > > > > in leaderEpochIndex as a ByteBuffer or byte array than a file
> > since it
> > > > will
> > > > > > be generated in memory.
> > > > > > 5102.6 RemoteLogSegmentMetadata: It seems that it needs both
> > > > baseOffset and
> > > > > > startOffset. For example, deleteRecords() could move the
> > startOffset
> > > > to the
> > > > > > middle of a segment. If we copy the full segment to remote
> > storage, the
> > > > > > baseOffset and the startOffset will be different.
> > > > > > 5102.7 Could we define all the public methods for
> > > > RemoteLogSegmentMetadata
> > > > > > and LogSegmentData?
> > > > > > 5102.8 Could we document whether endOffset in
> > RemoteLogSegmentMetadata
> > > > is
> > > > > > inclusive/exclusive?
> > > > > >
> > > > > > 5103. configs:
> > > > > > 5103.1 Could we define the default value of non-required configs
> > (e.g
> > > > the
> > > > > > size of new thread pools)?
> > > > > > 5103.2 It seems that local.log.retention.ms should default to
> > > > retention.ms,
> > > > > > instead of remote.log.retention.minutes. Similarly, it seems
> > > > > > that local.log.retention.bytes should default to segment.bytes.
> > > > > > 5103.3 remote.log.manager.thread.pool.size: The description says
> > "used
> > > > in
> > > > > > scheduling tasks to copy segments, fetch remote log indexes and
> > clean
> > > > up
> > > > > > remote log segments". However, there is a separate
> > > > > > config remote.log.reader.threads for fetching remote data. It's
> > weird
> > > > to
> > > > > > fetch remote index and log in different thread pools since both are
> > > > used
> > > > > > for serving fetch requests.
> > > > > > 5103.4 remote.log.manager.task.interval.ms: Is that the amount of
> > > > time to
> > > > > > back off when there is no work to do? If so, perhaps it can be
> > renamed
> > > > as
> > > > > > backoff.ms.
> > > > > > 5103.5 Are rlm_process_interval_ms and rlm_retry_interval_ms
> > configs?
> > > > If
> > > > > > so, they need to be listed in this section.
> > > > > >
> > > > > > 5104. "RLM maintains a bounded cache(possibly LRU) of the index
> > files
> > > > of
> > > > > > remote log segments to avoid multiple index fetches from the remote
> > > > > > storage." Is the RLM in memory or on disk? If on disk, where is it
> > > > stored?
> > > > > > Do we need a configuration to bound the size?
> > > > > >
> > > > > > 5105. The KIP uses local-log-start-offset and Earliest Local
> > Offset in
> > > > > > different places. It would be useful to standardize the
> > terminology.
> > > > > >
> > > > > > 5106. The section on "In BuildingRemoteLogAux state". It listed two
> > > > options
> > > > > > without saying which option is chosen.
> > > > > >
> > > > > > 5107. Follower to leader transition: It has step 2, but not step 1.
> > > > > >
> > > > > > 5108. If a consumer fetches from the remote data and the remote
> > > > storage is
> > > > > > not available, what error code is used in the fetch response?
> > > > > >
> > > > > > 5109. "ListOffsets: For timestamps >= 0, it returns the first
> > message
> > > > > > offset whose timestamp is >= to the given timestamp in the request.
> > > > That
> > > > > > means it checks in remote log time indexes first, after which
> > local log
> > > > > > time indexes are checked." Could you document which method in RLMM
> > is
> > > > used
> > > > > > for this?
> > > > > >
> > > > > > 5110. Stopreplica: "it sets all the remote log segment metadata of
> > that
> > > > > > partition with a delete marker and publishes them to RLMM." This
> > seems
> > > > > > outdated given the new topic deletion logic.
> > > > > >
> > > > > > 5111. "RLM follower fetches the earliest offset for the earliest
> > leader
> > > > > > epoch by calling RLMM.earliestLogOffset(TopicPartition
> > topicPartition,
> > > > int
> > > > > > leaderEpoch) and updates that as the log start offset." Do we need
> > that
> > > > > > since replication propagates logStartOffset already?
> > > > > >
> > > > > > 5112. Is the default maxWaitMs of 500ms enough for fetching from
> > remote
> > > > > > storage?
> > > > > >
> > > > > > 5113. "Committed offsets can be stored in a local file to avoid
> > > > reading the
> > > > > > messages again when a broker is restarted." Could you describe the
> > > > format
> > > > > > and the location of the file? Also, could the same message be
> > > > processed by
> > > > > > RLMM again after broker restart? If so, how do we handle that?
> > > > > >
> > > > > > 5114. Message format
> > > > > > 5114.1 There are two records named RemoteLogSegmentMetadataRecord
> > with
> > > > > > apiKey 0 and 1.
> > > > > > 5114.2 RemoteLogSegmentMetadataRecord: Could we document whether
> > > > endOffset
> > > > > > is inclusive/exclusive?
> > > > > > 5114.3 RemoteLogSegmentMetadataRecord: Could you explain
> > LeaderEpoch a
> > > > bit
> > > > > > more? Is that the epoch of the leader when it copies the segment to
> > > > remote
> > > > > > storage? Also, how will this field be used?
> > > > > > 5114.4 EventTimestamp: Could you explain this a bit more? Each
> > record
> > > > in
> > > > > > Kafka already has a timestamp field. Could we just use that?
> > > > > > 5114.5 SegmentSizeInBytes: Could this just be int32?
> > > > > >
> > > > > > 5115. RemoteLogCleaner(RLC): This could be confused with the log
> > > > cleaner
> > > > > > for compaction. Perhaps it can be renamed to sth like
> > > > > > RemotePartitionRemover.
> > > > > >
> > > > > > 5116. "RLC receives the delete_partition_marked and processes it
> > if it
> > > > is
> > > > > > not yet processed earlier." How does it know whether
> > > > > > delete_partition_marked has been processed earlier?
> > > > > >
> > > > > > 5117. Should we add a new MessageFormatter to read the tier
> > metadata
> > > > topic?
> > > > > >
> > > > > > 5118. "Maximum remote log reader thread pool task queue size. If
> > the
> > > > task
> > > > > > queue is full, broker will stop reading remote log segments." What
> > do
> > > > we
> > > > > > return to the fetch request in this case?
> > > > > >
> > > > > > 5119. It would be useful to list all things not supported in the
> > first
> > > > > > version in a Future work or Limitations section. For example,
> > compacted
> > > > > > topic, JBOD, changing remote.log.storage.enable from true to false,
> > > > etc.
> > > > > >
> > > > > > Thanks,
> > > > > >
> > > > > > Jun
> > > > > >
> > > > > > On Tue, Oct 27, 2020 at 5:57 PM Kowshik Prakasam <
> > > > kprakasam@confluent.io>
> > > > > > wrote:
> > > > > >
> > > > > > > Hi Satish,
> > > > > > >
> > > > > > > Thanks for the updates to the KIP. Here are my first batch of
> > > > > > > comments/suggestions on the latest version of the KIP.
> > > > > > >
> > > > > > > 5012. In the RemoteStorageManager interface, there is an API
> > defined
> > > > for
> > > > > > > each file type. For example, fetchOffsetIndex,
> > fetchTimestampIndex
> > > > etc. To
> > > > > > > avoid the duplication, I'd suggest we can instead have a FileType
> > > > enum and
> > > > > > > a common get API based on the FileType.
> > > > > > >
> > > > > > > 5013. There are some references to the Google doc in the KIP. I
> > > > wasn't sure
> > > > > > > if the Google doc is expected to be in sync with the contents of
> > the
> > > > wiki.
> > > > > > > Going forward, it seems easier if just the KIP is maintained as
> > the
> > > > source
> > > > > > > of truth. In this regard, could you please move all the
> > references
> > > > to the
> > > > > > > Google doc, maybe to a separate References section at the bottom
> > of
> > > > the
> > > > > > > KIP?
> > > > > > >
> > > > > > > 5014. There are some TODO sections in the KIP. Would these be
> > filled
> > > > up in
> > > > > > > future iterations?
> > > > > > >
> > > > > > > 5015. Under "Topic deletion lifecycle", I'm trying to understand
> > why
> > > > do we
> > > > > > > need delete_partition_marked as well as the
> > delete_partition_started
> > > > > > > messages. I couldn't spot a drawback if supposing we simplified
> > the
> > > > design
> > > > > > > such that the controller would only write
> > delete_partition_started
> > > > message,
> > > > > > > and RemoteLogCleaner (RLC) instance picks it up for processing.
> > What
> > > > am I
> > > > > > > missing?
> > > > > > >
> > > > > > > 5016. Under "Topic deletion lifecycle", step (4) is mentioned as
> > > > "RLC gets
> > > > > > > all the remote log segments for the partition and each of these
> > > > remote log
> > > > > > > segments is deleted with the next steps.". Since the RLC instance
> > > > runs on
> > > > > > > each tier topic partition leader, how does the RLC then get the
> > list
> > > > of
> > > > > > > remote log segments to be deleted? It will be useful to add that
> > > > detail to
> > > > > > > the KIP.
> > > > > > >
> > > > > > > 5017. Under "Public Interfaces -> Configs", there is a line
> > > > mentioning "We
> > > > > > > will support flipping remote.log.storage.enable in next
> > versions."
> > > > It will
> > > > > > > be useful to mention this in the "Future Work" section of the KIP
> > > > too.
> > > > > > >
> > > > > > > 5018. The KIP introduces a number of configuration parameters. It
> > > > will be
> > > > > > > useful to mention in the KIP if the user should assume these as
> > > > static
> > > > > > > configuration in the server.properties file, or dynamic
> > > > configuration which
> > > > > > > can be modified without restarting the broker.
> > > > > > >
> > > > > > > 5019.  Maybe this is planned as a future update to the KIP, but I
> > > > thought
> > > > > > > I'd mention it here. Could you please add details to the KIP on
> > why
> > > > RocksDB
> > > > > > > was chosen as the default cache implementation of RLMM, and how
> > it
> > > > is going
> > > > > > > to be used? Were alternatives compared/considered? For example,
> > it
> > > > would be
> > > > > > > useful to explain/evaluate the following: 1) debuggability of the
> > > > RocksDB
> > > > > > > JNI interface, 2) performance, 3) portability across platforms
> > and 4)
> > > > > > > interface parity of RocksDB’s JNI api with it's underlying C/C++
> > api.
> > > > > > >
> > > > > > > 5020. Following up on (5019), for the RocksDB cache, it will be
> > > > useful to
> > > > > > > explain the relationship/mapping between the following in the
> > KIP:
> > > > 1) # of
> > > > > > > tiered partitions, 2) # of partitions of metadata topic
> > > > > > > __remote_log_metadata and 3) # of RocksDB instances. i.e. is the
> > > > plan to
> > > > > > > have a RocksDB instance per tiered partition, or per metadata
> > topic
> > > > > > > partition, or just 1 for per broker?
> > > > > > >
> > > > > > > 5021. I was looking at the implementation prototype (PR link:
> > > > > > > https://github.com/apache/kafka/pull/7561). It seems that a
> > boolean
> > > > > > > attribute is being introduced into the Log layer to check if
> > remote
> > > > log
> > > > > > > capability is enabled. While the boolean footprint is small at
> > the
> > > > moment,
> > > > > > > this can easily grow in the future and become harder to
> > > > > > > test/maintain, considering that the Log layer is already pretty
> > > > complex. We
> > > > > > > should start thinking about how to manage such changes to the Log
> > > > layer
> > > > > > > (for the purpose of improved testability, better separation of
> > > > concerns and
> > > > > > > readability). One proposal I have is to take a step back and
> > define a
> > > > > > > higher level Log interface. Then, the Broker code can be changed
> > to
> > > > use
> > > > > > > this interface. It can be changed such that only a handle to the
> > > > interface
> > > > > > > is exposed to other components (such as LogCleaner,
> > ReplicaManager
> > > > etc.)
> > > > > > > and not the underlying Log object. This approach keeps the user
> > of
> > > > the Log
> > > > > > > layer agnostic of the whereabouts of the data. Underneath the
> > > > interface,
> > > > > > > the implementing classes can completely separate local log
> > > > capabilities
> > > > > > > from the remote log. For example, the Log class can be
> > simplified to
> > > > only
> > > > > > > manage logic surrounding local log segments and metadata.
> > > > Additionally, a
> > > > > > > wrapper class can be provided (implementing the higher level Log
> > > > interface)
> > > > > > > which will contain any/all logic surrounding tiered data. The
> > wrapper
> > > > > > > class will wrap around an instance of the Log class delegating
> > the
> > > > local
> > > > > > > log logic to it. Finally, a handle to the wrapper class can be
> > > > exposed to
> > > > > > > the other components wherever they need a handle to the higher
> > level
> > > > Log
> > > > > > > interface.
> > > > > > >
> > > > > > >
> > > > > > > Cheers,
> > > > > > > Kowshik
> > > > > > >
> > > > > > > On Mon, Oct 26, 2020 at 9:52 PM Satish Duggana <
> > > > satish.duggana@gmail.com>
> > > > > > > wrote:
> > > > > > >
> > > > > > > > Hi,
> > > > > > > > KIP is updated with 1) topic deletion lifecycle and its related
> > > > items
> > > > > > > > 2) Protocol changes(mainly related to ListOffsets) and other
> > minor
> > > > > > > > changes.
> > > > > > > > Please go through them and let us know your comments.
> > > > > > > >
> > > > > > > > Thanks,
> > > > > > > > Satish.
> > > > > > > >
> > > > > > > > On Mon, Sep 28, 2020 at 9:10 PM Satish Duggana <
> > > > satish.duggana@gmail.com
> > > > > > > >
> > > > > > > > wrote:
> > > > > > > > >
> > > > > > > > > Hi Dhruvil,
> > > > > > > > > Thanks for looking into the KIP and sending your comments.
> > Sorry
> > > > for
> > > > > > > > > the late reply, missed it in the mail thread.
> > > > > > > > >
> > > > > > > > > 1. Could you describe how retention would work with this KIP
> > and
> > > > which
> > > > > > > > > threads are responsible for driving this work? I believe
> > there
> > > > are 3
> > > > > > > > kinds
> > > > > > > > > of retention processes we are looking at:
> > > > > > > > >   (a) Regular retention for data in tiered storage as per
> > > > configured `
> > > > > > > > > retention.ms` / `retention.bytes`.
> > > > > > > > >   (b) Local retention for data in local storage as per
> > > > configured `
> > > > > > > > > local.log.retention.ms` / `local.log.retention.bytes`
> > > > > > > > >   (c) Possibly regular retention for data in local storage,
> > if
> > > > the
> > > > > > > > tiering
> > > > > > > > > task is lagging or for data that is below the log start
> > offset.
> > > > > > > > >
> > > > > > > > > Local log retention is done by the existing log cleanup
> > tasks.
> > > > These
> > > > > > > > > are not done for segments that are not yet copied to remote
> > > > storage.
> > > > > > > > > Remote log cleanup is done by the leader partition’s RLMTask.
> > > > > > > > >
> > > > > > > > > 2. When does a segment become eligible to be tiered? Is it as
> > > > soon as
> > > > > > > the
> > > > > > > > > segment is rolled and the end offset is less than the last
> > stable
> > > > > > > offset
> > > > > > > > as
> > > > > > > > > mentioned in the KIP? I wonder if we need to consider other
> > > > parameters
> > > > > > > > too,
> > > > > > > > > like the highwatermark so that we are guaranteed that what
> > we are
> > > > > > > tiering
> > > > > > > > > has been committed to the log and accepted by the ISR.
> > > > > > > > >
> > > > > > > > > AFAIK, last stable offset is always <= highwatermark. This
> > will
> > > > make
> > > > > > > > > sure we are always tiering the message segments which have
> > been
> > > > > > > > > accepted by ISR and transactionally completed.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > 3. The section on "Follower Fetch Scenarios" is useful but
> > is a
> > > > bit
> > > > > > > > > difficult to parse at the moment. It would be useful to
> > > > summarize the
> > > > > > > > > changes we need in the ReplicaFetcher.
> > > > > > > > >
> > > > > > > > > It may become difficult for users to read/follow if we add
> > code
> > > > changes
> > > > > > > > here.
> > > > > > > > >
> > > > > > > > > 4. Related to the above, it's a bit unclear how we are
> > planning
> > > > on
> > > > > > > > > restoring the producer state for a new replica. Could you
> > expand
> > > > on
> > > > > > > that?
> > > > > > > > >
> > > > > > > > > It is mentioned in the KIP BuildingRemoteLogAuxState is
> > > > introduced to
> > > > > > > > > build the state like leader epoch sequence and producer
> > snapshots
> > > > > > > > > before it starts fetching the data from the leader. We will
> > make
> > > > it
> > > > > > > > > clear in the KIP.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > 5. Similarly, it would be worth summarizing the behavior on
> > > > unclean
> > > > > > > > leader
> > > > > > > > > election. There are several scenarios to consider here: data
> > > > loss from
> > > > > > > > > local log, data loss from remote log, data loss from metadata
> > > > topic,
> > > > > > > etc.
> > > > > > > > > It's worth describing these in detail.
> > > > > > > > >
> > > > > > > > > We mentioned the cases about unclean leader election in the
> > > > follower
> > > > > > > > > fetch scenarios.
> > > > > > > > > If there are errors while fetching data from remote store or
> > > > metadata
> > > > > > > > > store, it will work the same way as it works with local log.
> > It
> > > > > > > > > returns the error back to the caller. Please let us know if
> > I am
> > > > > > > > > missing your point here.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > 7. For a READ_COMMITTED FetchRequest, how do we retrieve and
> > > > return the
> > > > > > > > > aborted transaction metadata?
> > > > > > > > >
> > > > > > > > > When a fetch for a remote log is accessed, we will fetch
> > aborted
> > > > > > > > > transactions along with the segment if it is not found in the
> > > > local
> > > > > > > > > index cache. This includes the case of transaction index not
> > > > existing
> > > > > > > > > in the remote log segment. That means, the cache entry can be
> > > > empty or
> > > > > > > > > have a list of aborted transactions.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > 8. The `LogSegmentData` class assumes that we have a log
> > segment,
> > > > > > > offset
> > > > > > > > > index, time index, transaction index, producer snapshot and
> > > > leader
> > > > > > > epoch
> > > > > > > > > index. How do we deal with cases where we do not have one or
> > > > more of
> > > > > > > > these?
> > > > > > > > > For example, we may not have a transaction index or producer
> > > > snapshot
> > > > > > > > for a
> > > > > > > > > particular segment. The former is optional, and the latter is
> > > > only kept
> > > > > > > > for
> > > > > > > > > up to the 3 latest segments.
> > > > > > > > >
> > > > > > > > > This is a good point,  we discussed this in the last meeting.
> > > > > > > > > Transaction index is optional and we will copy them only if
> > it
> > > > exists.
> > > > > > > > > We want to keep all the producer snapshots at each log
> > segment
> > > > rolling
> > > > > > > > > and they can be removed if the log copying is successful and
> > it
> > > > still
> > > > > > > > > maintains the existing latest 3 segments, We only delete the
> > > > producer
> > > > > > > > > snapshots which have been copied to remote log segments on
> > > > leader.
> > > > > > > > > Follower will keep the log segments beyond the segments which
> > > > have not
> > > > > > > > > been copied to remote storage. We will update the KIP with
> > these
> > > > > > > > > details.
> > > > > > > > >
> > > > > > > > > Thanks,
> > > > > > > > > Satish.
> > > > > > > > >
> > > > > > > > > On Thu, Sep 17, 2020 at 1:47 AM Dhruvil Shah <
> > > > dhruvil@confluent.io>
> > > > > > > > wrote:
> > > > > > > > > >
> > > > > > > > > > Hi Satish, Harsha,
> > > > > > > > > >
> > > > > > > > > > Thanks for the KIP. Few questions below:
> > > > > > > > > >
> > > > > > > > > > 1. Could you describe how retention would work with this
> > KIP
> > > > and
> > > > > > > which
> > > > > > > > > > threads are responsible for driving this work? I believe
> > there
> > > > are 3
> > > > > > > > kinds
> > > > > > > > > > of retention processes we are looking at:
> > > > > > > > > >   (a) Regular retention for data in tiered storage as per
> > > > configured
> > > > > > > `
> > > > > > > > > > retention.ms` / `retention.bytes`.
> > > > > > > > > >   (b) Local retention for data in local storage as per
> > > > configured `
> > > > > > > > > > local.log.retention.ms` / `local.log.retention.bytes`
> > > > > > > > > >   (c) Possibly regular retention for data in local
> > storage, if
> > > > the
> > > > > > > > tiering
> > > > > > > > > > task is lagging or for data that is below the log start
> > offset.
> > > > > > > > > >
> > > > > > > > > > 2. When does a segment become eligible to be tiered? Is it
> > as
> > > > soon as
> > > > > > > > the
> > > > > > > > > > segment is rolled and the end offset is less than the last
> > > > stable
> > > > > > > > offset as
> > > > > > > > > > mentioned in the KIP? I wonder if we need to consider other
> > > > > > > parameters
> > > > > > > > too,
> > > > > > > > > > like the highwatermark so that we are guaranteed that what
> > we
> > > > are
> > > > > > > > tiering
> > > > > > > > > > has been committed to the log and accepted by the ISR.
> > > > > > > > > >
> > > > > > > > > > 3. The section on "Follower Fetch Scenarios" is useful but
> > is
> > > > a bit
> > > > > > > > > > difficult to parse at the moment. It would be useful to
> > > > summarize the
> > > > > > > > > > changes we need in the ReplicaFetcher.
> > > > > > > > > >
> > > > > > > > > > 4. Related to the above, it's a bit unclear how we are
> > > > planning on
> > > > > > > > > > restoring the producer state for a new replica. Could you
> > > > expand on
> > > > > > > > that?
> > > > > > > > > >
> > > > > > > > > > 5. Similarly, it would be worth summarizing the behavior on
> > > > unclean
> > > > > > > > leader
> > > > > > > > > > election. There are several scenarios to consider here:
> > data
> > > > loss
> > > > > > > from
> > > > > > > > > > local log, data loss from remote log, data loss from
> > metadata
> > > > topic,
> > > > > > > > etc.
> > > > > > > > > > It's worth describing these in detail.
> > > > > > > > > >
> > > > > > > > > > 6. It would be useful to add details about how we plan on
> > using
> > > > > > > > RocksDB in
> > > > > > > > > > the default implementation of `RemoteLogMetadataManager`.
> > > > > > > > > >
> > > > > > > > > > 7. For a READ_COMMITTED FetchRequest, how do we retrieve
> > and
> > > > return
> > > > > > > the
> > > > > > > > > > aborted transaction metadata?
> > > > > > > > > >
> > > > > > > > > > 8. The `LogSegmentData` class assumes that we have a log
> > > > segment,
> > > > > > > > offset
> > > > > > > > > > index, time index, transaction index, producer snapshot and
> > > > leader
> > > > > > > > epoch
> > > > > > > > > > index. How do we deal with cases where we do not have one
> > or
> > > > more of
> > > > > > > > these?
> > > > > > > > > > For example, we may not have a transaction index or
> > producer
> > > > snapshot
> > > > > > > > for a
> > > > > > > > > > particular segment. The former is optional, and the latter
> > is
> > > > only
> > > > > > > > kept for
> > > > > > > > > > up to the 3 latest segments.
> > > > > > > > > >
> > > > > > > > > > Thanks,
> > > > > > > > > > Dhruvil
> > > > > > > > > >
> > > > > > > > > > On Mon, Sep 7, 2020 at 6:54 PM Harsha Ch <
> > harsha.ch@gmail.com>
> > > > > > > wrote:
> > > > > > > > > >
> > > > > > > > > > > Hi All,
> > > > > > > > > > >
> > > > > > > > > > > We are all working through the last meeting feedback.
> > I'll
> > > > cancel
> > > > > > > the
> > > > > > > > > > > tomorrow 's meeting and we can meanwhile continue our
> > > > discussion in
> > > > > > > > mailing
> > > > > > > > > > > list. We can start the regular meeting from next week
> > > > onwards.
> > > > > > > > > > >
> > > > > > > > > > > Thanks,
> > > > > > > > > > >
> > > > > > > > > > > Harsha
> > > > > > > > > > >
> > > > > > > > > > > On Fri, Sep 04, 2020 at 8:41 AM, Satish Duggana <
> > > > > > > > satish.duggana@gmail.com
> > > > > > > > > > > > wrote:
> > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > Hi Jun,
> > > > > > > > > > > > Thanks for your thorough review and comments. Please
> > find
> > > > the
> > > > > > > > inline
> > > > > > > > > > > > replies below.
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > 600. The topic deletion logic needs more details.
> > > > > > > > > > > > 600.1 The KIP mentions "The controller considers the
> > topic
> > > > > > > > partition is
> > > > > > > > > > > > deleted only when it determines that there are no log
> > > > segments
> > > > > > > for
> > > > > > > > that
> > > > > > > > > > > > topic partition by using RLMM". How is this done?
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > It uses RLMM#listSegments() returns all the segments
> > for
> > > > the
> > > > > > > given
> > > > > > > > topic
> > > > > > > > > > > > partition.
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > 600.2 "If the delete option is enabled then the leader
> > > > will stop
> > > > > > > > RLM task
> > > > > > > > > > > > and stop processing and it sets all the remote log
> > segment
> > > > > > > > metadata of
> > > > > > > > > > > > that partition with a delete marker and publishes them
> > to
> > > > RLMM."
> > > > > > > We
> > > > > > > > > > > > discussed this earlier. When a topic is being deleted,
> > > > there may
> > > > > > > > not be a
> > > > > > > > > > > > leader for the deleted partition.
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > This is a good point. As suggested in the meeting, we
> > will
> > > > add a
> > > > > > > > separate
> > > > > > > > > > > > section for topic/partition deletion lifecycle and this
> > > > scenario
> > > > > > > > will be
> > > > > > > > > > > > addressed.
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > 601. Unclean leader election
> > > > > > > > > > > > 601.1 Scenario 1: new empty follower
> > > > > > > > > > > > After step 1, the follower restores up to offset 3. So
> > why
> > > > does
> > > > > > > it
> > > > > > > > have
> > > > > > > > > > > > LE-2 <https://issues.apache.org/jira/browse/LE-2> at
> > > > offset 5?
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > Nice catch. It was showing the leader epoch fetched
> > from
> > > > the
> > > > > > > remote
> > > > > > > > > > > > storage. It should be shown with the truncated till
> > offset
> > > > 3.
> > > > > > > > Updated the
> > > > > > > > > > > > KIP.
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > 601.2 senario 5: After Step 3, leader A has
> > inconsistent
> > > > data
> > > > > > > > between its
> > > > > > > > > > > > local and the tiered data. For example. offset 3 has
> > msg 3
> > > > LE-0
> > > > > > > > <https://issues.apache.org/jira/browse/LE-0> locally,
> > > > > > > > > > > > but msg 5 LE-1 <
> > https://issues.apache.org/jira/browse/LE-1>
> > > > in
> > > > > > > > the remote store. While it's ok for the unclean leader
> > > > > > > > > > > > to lose data, it should still return consistent data,
> > > > whether
> > > > > > > it's
> > > > > > > > from
> > > > > > > > > > > > the local or the remote store.
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > There is no inconsistency here as LE-0
> > > > > > > > <https://issues.apache.org/jira/browse/LE-0> offsets are [0,
> > 4]
> > > > and LE-2
> > > > > > > > <https://issues.apache.org/jira/browse/LE-2>:
> > > > > > > > > > > > [5, ]. It will always get the right records for the
> > given
> > > > offset
> > > > > > > > and
> > > > > > > > > > > > leader epoch. In case of remote, RSM is invoked to get
> > the
> > > > remote
> > > > > > > > log
> > > > > > > > > > > > segment that contains the given offset with the leader
> > > > epoch.
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > 601.4 It seems that retention is based on
> > > > > > > > > > > > listRemoteLogSegments(TopicPartition topicPartition,
> > long
> > > > > > > > leaderEpoch).
> > > > > > > > > > > > When there is an unclean leader election, it's possible
> > > > for the
> > > > > > > new
> > > > > > > > > > > leader
> > > > > > > > > > > > to not to include certain epochs in its epoch cache.
> > How
> > > > are
> > > > > > > remote
> > > > > > > > > > > > segments associated with those epochs being cleaned?
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > That is a good point. This leader will also cleanup the
> > > > epochs
> > > > > > > > earlier to
> > > > > > > > > > > > its start leader epoch and delete those segments. It
> > gets
> > > > the
> > > > > > > > earliest
> > > > > > > > > > > > epoch for a partition and starts deleting segments from
> > > > that
> > > > > > > leader
> > > > > > > > > > > epoch.
> > > > > > > > > > > > We need one more API in RLMM to get the earliest leader
> > > > epoch.
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > 601.5 The KIP discusses the handling of unclean leader
> > > > elections
> > > > > > > > for user
> > > > > > > > > > > > topics. What about unclean leader elections on
> > > > > > > > > > > > __remote_log_segment_metadata?
> > > > > > > > > > > > This is the same as other system topics like
> > > > consumer_offsets,
> > > > > > > > > > > > __transaction_state topics. As discussed in the
> > meeting,
> > > > we will
> > > > > > > > add the
> > > > > > > > > > > > behavior of __remote_log_segment_metadata topic’s
> > unclean
> > > > leader
> > > > > > > > > > > > truncation.
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > 602. It would be useful to clarify the limitations in
> > the
> > > > initial
> > > > > > > > > > > release.
> > > > > > > > > > > > The KIP mentions not supporting compacted topics. What
> > > > about JBOD
> > > > > > > > and
> > > > > > > > > > > > changing the configuration of a topic from delete to
> > > > compact
> > > > > > > after
> > > > > > > > > > > remote.
> > > > > > > > > > > > log. storage. enable (
> > http://remote.log.storage.enable/
> > > > ) is
> > > > > > > > enabled?
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > This was updated in the KIP earlier.
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > 603. RLM leader tasks:
> > > > > > > > > > > > 603.1"It checks for rolled over LogSegments (which have
> > > > the last
> > > > > > > > message
> > > > > > > > > > > > offset less than last stable offset of that topic
> > > > partition) and
> > > > > > > > copies
> > > > > > > > > > > > them along with their offset/time/transaction indexes
> > and
> > > > leader
> > > > > > > > epoch
> > > > > > > > > > > > cache to the remote tier." It needs to copy the
> > producer
> > > > snapshot
> > > > > > > > too.
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > Right. It copies producer snapshots too as mentioned in
> > > > > > > > LogSegmentData.
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > 603.2 "Local logs are not cleaned up till those
> > segments
> > > > are
> > > > > > > copied
> > > > > > > > > > > > successfully to remote even though their retention
> > > > time/size is
> > > > > > > > reached"
> > > > > > > > > > > > This seems weird. If the tiering stops because the
> > remote
> > > > store
> > > > > > > is
> > > > > > > > not
> > > > > > > > > > > > available, we don't want the local data to grow
> > forever.
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > It was clarified in the discussion that the comment was
> > > > more
> > > > > > > about
> > > > > > > > the
> > > > > > > > > > > > local storage goes beyond the log.retention. The above
> > > > statement
> > > > > > > > is about
> > > > > > > > > > > > local.log.retention but not for the complete
> > > > log.retention. When
> > > > > > > it
> > > > > > > > > > > > reaches the log.retention then it will delete the local
> > > > logs even
> > > > > > > > though
> > > > > > > > > > > > those are not copied to remote storage.
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > 604. "RLM maintains a bounded cache(possibly LRU) of
> > the
> > > > index
> > > > > > > > files of
> > > > > > > > > > > > remote log segments to avoid multiple index fetches
> > from
> > > > the
> > > > > > > remote
> > > > > > > > > > > > storage. These indexes can be used in the same way as
> > local
> > > > > > > segment
> > > > > > > > > > > > indexes are used." Could you provide more details on
> > this?
> > > > Are
> > > > > > > the
> > > > > > > > > > > indexes
> > > > > > > > > > > > cached in memory or on disk? If on disk, where are they
> > > > stored?
> > > > > > > > Are the
> > > > > > > > > > > > cached indexes bound by a certain size?
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > These are cached on disk and stored in log.dir with a
> > name
> > > > > > > > > > > > “__remote_log_index_cache”. They are bound by the total
> > > > size.
> > > > > > > This
> > > > > > > > will
> > > > > > > > > > > be
> > > > > > > > > > > > exposed as a user configuration,
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > 605. BuildingRemoteLogAux
> > > > > > > > > > > > 605.1 In this section, two options are listed. Which
> > one is
> > > > > > > chosen?
> > > > > > > > > > > > Option-2, updated the KIP.
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > 605.2 In option 2, it says "Build the local leader
> > epoch
> > > > cache by
> > > > > > > > cutting
> > > > > > > > > > > > the leader epoch sequence received from remote storage
> > to
> > > > [LSO,
> > > > > > > > ELO].
> > > > > > > > > > > (LSO
> > > > > > > > > > > >
> > > > > > > > > > > > = log start offset)." We need to do the same thing for
> > the
> > > > > > > producer
> > > > > > > > > > > > snapshot. However, it's hard to cut the producer
> > snapshot
> > > > to an
> > > > > > > > earlier
> > > > > > > > > > > > offset. Another option is to simply take the lastOffset
> > > > from the
> > > > > > > > remote
> > > > > > > > > > > > segment and use that as the starting fetch offset in
> > the
> > > > > > > follower.
> > > > > > > > This
> > > > > > > > > > > > avoids the need for cutting.
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > Right, this was mentioned in the “transactional
> > support”
> > > > section
> > > > > > > > about
> > > > > > > > > > > > adding these details.
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > 606. ListOffsets: Since we need a version bump, could
> > you
> > > > > > > document
> > > > > > > > it
> > > > > > > > > > > > under a protocol change section?
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > Sure, we will update the KIP.
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > 607. "LogStartOffset of a topic can point to either of
> > > > local
> > > > > > > > segment or
> > > > > > > > > > > > remote segment but it is initialised and maintained in
> > the
> > > > Log
> > > > > > > > class like
> > > > > > > > > > > > now. This is already maintained in `Log` class while
> > > > loading the
> > > > > > > > logs and
> > > > > > > > > > > > it can also be fetched from RemoteLogMetadataManager."
> > > > What will
> > > > > > > > happen
> > > > > > > > > > > to
> > > > > > > > > > > > the existing logic (e.g. log recovery) that currently
> > > > depends on
> > > > > > > > > > > > logStartOffset but assumes it's local?
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > They use a field called localLogStartOffset which is
> > the
> > > > local
> > > > > > > log
> > > > > > > > start
> > > > > > > > > > > > offset..
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > 608. Handle expired remote segment: How does it pick
> > up new
> > > > > > > > > > > logStartOffset
> > > > > > > > > > > > from deleteRecords?
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > Good point. This was not addressed in the KIP. Will
> > update
> > > > the
> > > > > > > KIP
> > > > > > > > on how
> > > > > > > > > > > > the RLM task handles this scenario.
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > 609. RLMM message format:
> > > > > > > > > > > > 609.1 It includes both MaxTimestamp and EventTimestamp.
> > > > Where
> > > > > > > does
> > > > > > > > it get
> > > > > > > > > > > > both since the message in the log only contains one
> > > > timestamp?
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > `EventTimeStamp` is the timestamp at which that segment
> > > > metadata
> > > > > > > > event is
> > > > > > > > > > > > generated. This is more for audits.
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > 609.2 If we change just the state (e.g. to
> > > > DELETE_STARTED), it
> > > > > > > > seems it's
> > > > > > > > > > > > wasteful to have to include all other fields not
> > changed.
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > This is a good point. We thought about incremental
> > > > updates. But
> > > > > > > we
> > > > > > > > want
> > > > > > > > > > > to
> > > > > > > > > > > > make sure all the events are in the expected order and
> > take
> > > > > > > action
> > > > > > > > based
> > > > > > > > > > > > on the latest event. Will think through the approaches
> > in
> > > > detail
> > > > > > > > and
> > > > > > > > > > > > update here.
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > 609.3 Could you document which process makes the
> > following
> > > > > > > > transitions
> > > > > > > > > > > > DELETE_MARKED, DELETE_STARTED, DELETE_FINISHED?
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > Okay, will document more details.
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > 610. remote.log.reader.max.pending.tasks: "Maximum
> > remote
> > > > log
> > > > > > > > reader
> > > > > > > > > > > > thread pool task queue size. If the task queue is full,
> > > > broker
> > > > > > > > will stop
> > > > > > > > > > > > reading remote log segments." What does the broker do
> > if
> > > > the
> > > > > > > queue
> > > > > > > > is
> > > > > > > > > > > > full?
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > It returns an error for this topic partition.
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > 611. What do we return if the request offset/epoch
> > doesn't
> > > > exist
> > > > > > > > in the
> > > > > > > > > > > > following API?
> > > > > > > > > > > > RemoteLogSegmentMetadata
> > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > > > > topicPartition, long offset, int epochForOffset)
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > This returns null. But we prefer to update the return
> > type
> > > > as
> > > > > > > > Optional
> > > > > > > > > > > and
> > > > > > > > > > > > return Empty if that does not exist.
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > Thanks,
> > > > > > > > > > > > Satish.
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > On Tue, Sep 1, 2020 at 9:45 AM Jun Rao < jun@
> > confluent.
> > > > io (
> > > > > > > > > > > > jun@confluent.io ) > wrote:
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > >>
> > > > > > > > > > > >>
> > > > > > > > > > > >> Hi, Satish,
> > > > > > > > > > > >>
> > > > > > > > > > > >>
> > > > > > > > > > > >>
> > > > > > > > > > > >> Thanks for the updated KIP. Made another pass. A few
> > more
> > > > > > > comments
> > > > > > > > > > > below.
> > > > > > > > > > > >>
> > > > > > > > > > > >>
> > > > > > > > > > > >>
> > > > > > > > > > > >> 600. The topic deletion logic needs more details.
> > > > > > > > > > > >> 600.1 The KIP mentions "The controller considers the
> > topic
> > > > > > > > partition is
> > > > > > > > > > > >> deleted only when it determines that there are no log
> > > > segments
> > > > > > > > for that
> > > > > > > > > > > >> topic partition by using RLMM". How is this done?
> > 600.2
> > > > "If the
> > > > > > > > delete
> > > > > > > > > > > >> option is enabled then the leader will stop RLM task
> > and
> > > > stop
> > > > > > > > processing
> > > > > > > > > > > >> and it sets all the remote log segment metadata of
> > that
> > > > > > > partition
> > > > > > > > with a
> > > > > > > > > > > >> delete marker and publishes them to RLMM." We
> > discussed
> > > > this
> > > > > > > > earlier.
> > > > > > > > > > > When
> > > > > > > > > > > >> a topic is being deleted, there may not be a leader
> > for
> > > > the
> > > > > > > > deleted
> > > > > > > > > > > >> partition.
> > > > > > > > > > > >>
> > > > > > > > > > > >>
> > > > > > > > > > > >>
> > > > > > > > > > > >> 601. Unclean leader election
> > > > > > > > > > > >> 601.1 Scenario 1: new empty follower
> > > > > > > > > > > >> After step 1, the follower restores up to offset 3. So
> > > > why does
> > > > > > > > it have
> > > > > > > > > > > >> LE-2 <https://issues.apache.org/jira/browse/LE-2> at
> > > > offset 5?
> > > > > > > > > > > >> 601.2 senario 5: After Step 3, leader A has
> > inconsistent
> > > > data
> > > > > > > > between
> > > > > > > > > > > its
> > > > > > > > > > > >> local and the tiered data. For example. offset 3 has
> > msg
> > > > 3 LE-0
> > > > > > > > <https://issues.apache.org/jira/browse/LE-0> locally,
> > > > > > > > > > > >> but msg 5 LE-1 <
> > > > https://issues.apache.org/jira/browse/LE-1> in
> > > > > > > > the remote store. While it's ok for the unclean leader
> > > > > > > > > > > >> to lose data, it should still return consistent data,
> > > > whether
> > > > > > > > it's from
> > > > > > > > > > > >> the local or the remote store.
> > > > > > > > > > > >> 601.3 The follower picks up log start offset using the
> > > > following
> > > > > > > > api.
> > > > > > > > > > > >> Suppose that we have 3 remote segments (LE,
> > > > SegmentStartOffset)
> > > > > > > > as (2,
> > > > > > > > > > > >> 10),
> > > > > > > > > > > >> (3, 20) and (7, 15) due to an unclean leader election.
> > > > Using the
> > > > > > > > > > > following
> > > > > > > > > > > >> api will cause logStartOffset to go backward from 20
> > to
> > > > 15. How
> > > > > > > > do we
> > > > > > > > > > > >> prevent that?
> > > > > > > > > > > >> earliestLogOffset(TopicPartition topicPartition, int
> > > > > > > leaderEpoch)
> > > > > > > > 601.4
> > > > > > > > > > > It
> > > > > > > > > > > >> seems that retention is based on
> > > > > > > > > > > >> listRemoteLogSegments(TopicPartition topicPartition,
> > long
> > > > > > > > leaderEpoch).
> > > > > > > > > > > >> When there is an unclean leader election, it's
> > possible
> > > > for the
> > > > > > > > new
> > > > > > > > > > > leader
> > > > > > > > > > > >> to not to include certain epochs in its epoch cache.
> > How
> > > > are
> > > > > > > > remote
> > > > > > > > > > > >> segments associated with those epochs being cleaned?
> > > > 601.5 The
> > > > > > > KIP
> > > > > > > > > > > >> discusses the handling of unclean leader elections for
> > > > user
> > > > > > > > topics. What
> > > > > > > > > > > >> about unclean leader elections on
> > > > > > > > > > > >> __remote_log_segment_metadata?
> > > > > > > > > > > >>
> > > > > > > > > > > >>
> > > > > > > > > > > >>
> > > > > > > > > > > >> 602. It would be useful to clarify the limitations in
> > the
> > > > > > > initial
> > > > > > > > > > > release.
> > > > > > > > > > > >> The KIP mentions not supporting compacted topics. What
> > > > about
> > > > > > > JBOD
> > > > > > > > and
> > > > > > > > > > > >> changing the configuration of a topic from delete to
> > > > compact
> > > > > > > after
> > > > > > > > > > > remote.
> > > > > > > > > > > >> log. storage. enable (
> > http://remote.log.storage.enable/
> > > > ) is
> > > > > > > > enabled?
> > > > > > > > > > > >>
> > > > > > > > > > > >>
> > > > > > > > > > > >>
> > > > > > > > > > > >> 603. RLM leader tasks:
> > > > > > > > > > > >> 603.1"It checks for rolled over LogSegments (which
> > have
> > > > the last
> > > > > > > > message
> > > > > > > > > > > >> offset less than last stable offset of that topic
> > > > partition) and
> > > > > > > > copies
> > > > > > > > > > > >> them along with their offset/time/transaction indexes
> > and
> > > > leader
> > > > > > > > epoch
> > > > > > > > > > > >> cache to the remote tier." It needs to copy the
> > producer
> > > > > > > snapshot
> > > > > > > > too.
> > > > > > > > > > > >> 603.2 "Local logs are not cleaned up till those
> > segments
> > > > are
> > > > > > > > copied
> > > > > > > > > > > >> successfully to remote even though their retention
> > > > time/size is
> > > > > > > > reached"
> > > > > > > > > > > >> This seems weird. If the tiering stops because the
> > remote
> > > > store
> > > > > > > > is not
> > > > > > > > > > > >> available, we don't want the local data to grow
> > forever.
> > > > > > > > > > > >>
> > > > > > > > > > > >>
> > > > > > > > > > > >>
> > > > > > > > > > > >> 604. "RLM maintains a bounded cache(possibly LRU) of
> > the
> > > > index
> > > > > > > > files of
> > > > > > > > > > > >> remote log segments to avoid multiple index fetches
> > from
> > > > the
> > > > > > > > remote
> > > > > > > > > > > >> storage. These indexes can be used in the same way as
> > > > local
> > > > > > > > segment
> > > > > > > > > > > >> indexes are used." Could you provide more details on
> > > > this? Are
> > > > > > > the
> > > > > > > > > > > indexes
> > > > > > > > > > > >> cached in memory or on disk? If on disk, where are
> > they
> > > > stored?
> > > > > > > > Are the
> > > > > > > > > > > >> cached indexes bound by a certain size?
> > > > > > > > > > > >>
> > > > > > > > > > > >>
> > > > > > > > > > > >>
> > > > > > > > > > > >> 605. BuildingRemoteLogAux
> > > > > > > > > > > >> 605.1 In this section, two options are listed. Which
> > one
> > > > is
> > > > > > > > chosen?
> > > > > > > > > > > 605.2
> > > > > > > > > > > >> In option 2, it says "Build the local leader epoch
> > cache
> > > > by
> > > > > > > > cutting the
> > > > > > > > > > > >> leader epoch sequence received from remote storage to
> > > > [LSO,
> > > > > > > ELO].
> > > > > > > > (LSO
> > > > > > > > > > > >> = log start offset)." We need to do the same thing
> > for the
> > > > > > > > producer
> > > > > > > > > > > >> snapshot. However, it's hard to cut the producer
> > snapshot
> > > > to an
> > > > > > > > earlier
> > > > > > > > > > > >> offset. Another option is to simply take the
> > lastOffset
> > > > from the
> > > > > > > > remote
> > > > > > > > > > > >> segment and use that as the starting fetch offset in
> > the
> > > > > > > > follower. This
> > > > > > > > > > > >> avoids the need for cutting.
> > > > > > > > > > > >>
> > > > > > > > > > > >>
> > > > > > > > > > > >>
> > > > > > > > > > > >> 606. ListOffsets: Since we need a version bump, could
> > you
> > > > > > > > document it
> > > > > > > > > > > >> under a protocol change section?
> > > > > > > > > > > >>
> > > > > > > > > > > >>
> > > > > > > > > > > >>
> > > > > > > > > > > >> 607. "LogStartOffset of a topic can point to either of
> > > > local
> > > > > > > > segment or
> > > > > > > > > > > >> remote segment but it is initialised and maintained in
> > > > the Log
> > > > > > > > class
> > > > > > > > > > > like
> > > > > > > > > > > >> now. This is already maintained in `Log` class while
> > > > loading the
> > > > > > > > logs
> > > > > > > > > > > and
> > > > > > > > > > > >> it can also be fetched from RemoteLogMetadataManager."
> > > > What will
> > > > > > > > happen
> > > > > > > > > > > to
> > > > > > > > > > > >> the existing logic (e.g. log recovery) that currently
> > > > depends on
> > > > > > > > > > > >> logStartOffset but assumes it's local?
> > > > > > > > > > > >>
> > > > > > > > > > > >>
> > > > > > > > > > > >>
> > > > > > > > > > > >> 608. Handle expired remote segment: How does it pick
> > up
> > > > new
> > > > > > > > > > > logStartOffset
> > > > > > > > > > > >> from deleteRecords?
> > > > > > > > > > > >>
> > > > > > > > > > > >>
> > > > > > > > > > > >>
> > > > > > > > > > > >> 609. RLMM message format:
> > > > > > > > > > > >> 609.1 It includes both MaxTimestamp and
> > EventTimestamp.
> > > > Where
> > > > > > > > does it
> > > > > > > > > > > get
> > > > > > > > > > > >> both since the message in the log only contains one
> > > > timestamp?
> > > > > > > > 609.2 If
> > > > > > > > > > > we
> > > > > > > > > > > >> change just the state (e.g. to DELETE_STARTED), it
> > seems
> > > > it's
> > > > > > > > wasteful
> > > > > > > > > > > to
> > > > > > > > > > > >> have to include all other fields not changed. 609.3
> > Could
> > > > you
> > > > > > > > document
> > > > > > > > > > > >> which process makes the following transitions
> > > > DELETE_MARKED,
> > > > > > > > > > > >> DELETE_STARTED, DELETE_FINISHED?
> > > > > > > > > > > >>
> > > > > > > > > > > >>
> > > > > > > > > > > >>
> > > > > > > > > > > >> 610. remote.log.reader.max.pending.tasks: "Maximum
> > remote
> > > > log
> > > > > > > > reader
> > > > > > > > > > > >> thread pool task queue size. If the task queue is
> > full,
> > > > broker
> > > > > > > > will stop
> > > > > > > > > > > >> reading remote log segments." What does the broker do
> > if
> > > > the
> > > > > > > > queue is
> > > > > > > > > > > >> full?
> > > > > > > > > > > >>
> > > > > > > > > > > >>
> > > > > > > > > > > >>
> > > > > > > > > > > >> 611. What do we return if the request offset/epoch
> > > > doesn't exist
> > > > > > > > in the
> > > > > > > > > > > >> following API?
> > > > > > > > > > > >> RemoteLogSegmentMetadata
> > > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > > > >> topicPartition, long offset, int epochForOffset)
> > > > > > > > > > > >>
> > > > > > > > > > > >>
> > > > > > > > > > > >>
> > > > > > > > > > > >> Jun
> > > > > > > > > > > >>
> > > > > > > > > > > >>
> > > > > > > > > > > >>
> > > > > > > > > > > >> On Mon, Aug 31, 2020 at 11:19 AM Satish Duggana <
> > satish.
> > > > > > > duggana@
> > > > > > > > > > > gmail. com
> > > > > > > > > > > >> ( satish.duggana@gmail.com ) > wrote:
> > > > > > > > > > > >>
> > > > > > > > > > > >>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>> KIP is updated with
> > > > > > > > > > > >>> - Remote log segment metadata topic message
> > > > format/schema.
> > > > > > > > > > > >>> - Added remote log segment metadata state
> > transitions and
> > > > > > > > explained how
> > > > > > > > > > > >>> the deletion of segments is handled, including the
> > case
> > > > of
> > > > > > > > partition
> > > > > > > > > > > >>> deletions.
> > > > > > > > > > > >>> - Added a few more limitations in the "Non goals"
> > > > section.
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>> Thanks,
> > > > > > > > > > > >>> Satish.
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>> On Thu, Aug 27, 2020 at 12:42 AM Harsha Ch < harsha.
> > ch@
> > > > > > > gmail.
> > > > > > > > com (
> > > > > > > > > > > >>> harsha.ch@gmail.com ) > wrote:
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>> Updated the KIP with Meeting Notes section
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>> https:/ / cwiki. apache. org/ confluence/ display/
> > KAFKA/
> > > > > > > > > > > KIP-405 <https://issues.apache.org/jira/browse/KIP-405>
> > > > > > > > %3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> > > > > > > > > > > >>> (
> > > > > > > > > > > >>>
> > > > > > > > > > >
> > > > > > > >
> > > > > > >
> > > >
> > https://cwiki.apache.org/confluence/display/KAFKA/KIP-405%3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> > > > > > > > > > > >>> )
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>> On Tue, Aug 25, 2020 at 1:03 PM Jun Rao < jun@
> > > > confluent. io
> > > > > > > (
> > > > > > > > > > > >>>> jun@confluent.io ) > wrote:
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>> Hi, Harsha,
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>> Thanks for the summary. Could you add the summary
> > and
> > > > the
> > > > > > > > recording
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>> link to
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>> the last section of
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>> https:/ / cwiki. apache. org/ confluence/ display/
> > KAFKA/
> > > > > > > > > > > Kafka+Improvement+Proposals
> > > > > > > > > > > >>> (
> > > > > > > > > > > >>>
> > > > > > > > > > >
> > > > > > > >
> > > > > > >
> > > >
> > https://cwiki.apache.org/confluence/display/KAFKA/Kafka+Improvement+Proposals
> > > > > > > > > > > >>> )
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>> ?
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>> Jun
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>> On Tue, Aug 25, 2020 at 11:12 AM Harsha
> > Chintalapani <
> > > > kafka@
> > > > > > > > > > > harsha. io (
> > > > > > > > > > > >>>>> kafka@harsha.io ) > wrote:
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>> Thanks everyone for attending the meeting today.
> > > > > > > > > > > >>>>>> Here is the recording
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>> https:/ / drive. google. com/ file/ d/
> > > > > > > > > > > 14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/ view?usp=sharing
> > > > > > > > > > > >>> (
> > > > > > > > > > > >>>
> > > > > > > > > > >
> > > > > > > >
> > > > > > >
> > > >
> > https://drive.google.com/file/d/14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/view?usp=sharing
> > > > > > > > > > > >>> )
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>> Notes:
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>> 1. KIP is updated with follower fetch protocol and
> > > > ready to
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>> reviewed
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>> 2. Satish to capture schema of internal metadata
> > > > topic in
> > > > > > > the
> > > > > > > > KIP
> > > > > > > > > > > >>>>>> 3. We will update the KIP with details of
> > different
> > > > cases
> > > > > > > > > > > >>>>>> 4. Test plan will be captured in a doc and will
> > add
> > > > to the
> > > > > > > KIP
> > > > > > > > > > > >>>>>> 5. Add a section "Limitations" to capture the
> > > > capabilities
> > > > > > > > that
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>> will
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>> be
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>> introduced with this KIP and what will not be
> > covered
> > > > in
> > > > > > > this
> > > > > > > > KIP.
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>> Please add to it I missed anything. Will produce a
> > > > formal
> > > > > > > > meeting
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>> notes
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>> from next meeting onwards.
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>> Thanks,
> > > > > > > > > > > >>>>>> Harsha
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>> On Mon, Aug 24, 2020 at 9:42 PM, Ying Zheng <
> > yingz@
> > > > uber.
> > > > > > > > com.
> > > > > > > > > > > invalid (
> > > > > > > > > > > >>>>>> yingz@uber.com.invalid ) > wrote:
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> We did some basic feature tests at Uber. The test
> > > > cases and
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>> results are
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> shared in this google doc:
> > > > > > > > > > > >>>>>>> https:/ / docs. google. com/ spreadsheets/ d/ (
> > > > > > > > > > > >>>>>>> https://docs.google.com/spreadsheets/d/ )
> > > > > > > > > > > >>>>>>>
> > > > > > > 1XhNJqjzwXvMCcAOhEH0sSXU6RTvyoSf93DHF-YMfGLk/edit?usp=sharing
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> The performance test results were already shared
> > in
> > > > the KIP
> > > > > > > > last
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>> month.
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> On Mon, Aug 24, 2020 at 11:10 AM Harsha Ch <
> > harsha.
> > > > ch@
> > > > > > > > gmail.
> > > > > > > > > > > com (
> > > > > > > > > > > >>>>>>> harsha.ch@gmail.com ) >
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>> wrote:
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> "Understand commitments towards driving design &
> > > > > > > > implementation of
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>> the
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>> KIP
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> further and how it aligns with participant
> > interests
> > > > in
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>> contributing to
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>> the
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> efforts (ex: in the context of Uber’s Q3/Q4
> > > > roadmap)." What
> > > > > > > > is that
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>> about?
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> On Mon, Aug 24, 2020 at 11:05 AM Kowshik
> > Prakasam <
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>> kprakasam@ confluent. io ( kprakasam@confluent.io
> > ) >
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> wrote:
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> Hi Harsha,
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> The following google doc contains a proposal for
> > > > temporary
> > > > > > > > agenda
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>> for
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>> the
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> KIP-405 <
> > > > https://issues.apache.org/jira/browse/KIP-405> <
> > > > > > > > https:/ / issues. apache. org/ jira/ browse/ KIP-405
> > > > > > > > <https://issues.apache.org/jira/browse/KIP-405> (
> > > > > > > > > > > >>>>>>> https://issues.apache.org/jira/browse/KIP-405 )
> > >
> > > > sync
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>> meeting
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> tomorrow:
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> https:/ / docs. google. com/ document/ d/ (
> > > > > > > > > > > >>>>>>> https://docs.google.com/document/d/ )
> > > > > > > > > > > >>>>>>> 1pqo8X5LU8TpwfC_iqSuVPezhfCfhGkbGN2TqiPA3LBU/edit
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> .
> > > > > > > > > > > >>>>>>> Please could you add it to the Google calendar
> > > > invite?
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> Thank you.
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> Cheers,
> > > > > > > > > > > >>>>>>> Kowshik
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> On Thu, Aug 20, 2020 at 10:58 AM Harsha Ch <
> > harsha.
> > > > ch@
> > > > > > > > gmail.
> > > > > > > > > > > com (
> > > > > > > > > > > >>>>>>> harsha.ch@gmail.com ) >
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>> wrote:
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> Hi All,
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> Scheduled a meeting for Tuesday 9am - 10am. I can
> > > > record
> > > > > > > and
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>> upload for
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> community to be able to follow the discussion.
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> Jun, please add the required folks on confluent
> > side.
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> Thanks,
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> Harsha
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> On Thu, Aug 20, 2020 at 12:33 AM, Alexandre
> > Dupriez <
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>> alexandre.dupriez@
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> gmail. com ( http://gmail.com/ ) > wrote:
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> Hi Jun,
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> Many thanks for your initiative.
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> If you like, I am happy to attend at the time you
> > > > > > > suggested.
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> Many thanks,
> > > > > > > > > > > >>>>>>> Alexandre
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> Le mer. 19 août 2020 à 22:00, Harsha Ch <
> > harsha. ch@
> > > > > > > > gmail. com (
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>> harsha.
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> ch@ gmail. com ( ch@gmail.com ) ) > a écrit :
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> Hi Jun,
> > > > > > > > > > > >>>>>>> Thanks. This will help a lot. Tuesday will work
> > for
> > > > us.
> > > > > > > > > > > >>>>>>> -Harsha
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> On Wed, Aug 19, 2020 at 1:24 PM Jun Rao < jun@
> > > > confluent.
> > > > > > > > io (
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>> jun@
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> confluent. io ( http://confluent.io/ ) ) >
> > wrote:
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> Hi, Satish, Ying, Harsha,
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> Do you think it would be useful to have a regular
> > > > virtual
> > > > > > > > meeting
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>> to
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>
> > > > > > > > > > > >>>>
> > > > > > > > > > > >>>>>
> > > > > > > > > > > >>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> discuss this KIP? The goal of the meeting will be
> > > > sharing
> > > > > > > > > > > >>>>>>> design/development progress and discussing any
> > open
> > > > issues
> > > > > > > to
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> accelerate
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> this KIP. If so, will every Tuesday (from next
> > week)
> > > > > > > 9am-10am
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> PT
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> work for you? I can help set up a Zoom meeting,
> > > > invite
> > > > > > > > everyone who
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> might
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> be interested, have it recorded and shared, etc.
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> Thanks,
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> Jun
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> On Tue, Aug 18, 2020 at 11:01 AM Satish Duggana <
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> satish. duggana@ gmail. com ( satish. duggana@
> > > > gmail. com
> > > > > > > (
> > > > > > > > > > > >>>>>>> satish.duggana@gmail.com ) ) >
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> wrote:
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> Hi Kowshik,
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> Thanks for looking into the KIP and sending your
> > > > comments.
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>>
> > > > > > > > > > > >>>>>>> 5001. Under the section "Follower fetch protocol
> > in
> > > > > > > detail",
> > > > > > > > the
> > > > > > > > > > > >>>>>>> next-local-offset is the offset upto which the
> > > > segments are
> > > > > > > > copied
> > > > > > > > > > > >>>>>>>
> > > > > > > >
> > > >
> > > >
> >

Re: [DISCUSS] KIP-405: Kafka Tiered Storage

[Jun Rao <ju...@confluent.io>]

Hi, Satish,

Thanks for the reply. A few more comments below.

5102.2: It seems that both positions can just be int. Another option is to
have two methods. Would it be clearer?

    InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
remoteLogSegmentMetadata,
                                    int startPosition) throws
RemoteStorageException;

    InputStream fetchLogSegmentData(RemoteLogSegmentMetadata
remoteLogSegmentMetadata,
                                    int startPosition, int endPosition)
throws RemoteStorageException;

6003: Could you also update the javadoc for the return value?

6010: What kind of tiering throughput have you seen with 5 threads?

6020: local.log.retention.bytes: Should it default to log.retention.bytes
to be consistent with local.log.retention.ms?

6021: Could you define TopicIdPartition?

6022: For all public facing classes, could you specify the package name?

It seems that you already added the topicId support. Two other remaining
items are (a) the format of local tier metadata storage and (b) upgrade.

Jun

On Mon, Dec 7, 2020 at 8:56 AM Satish Duggana <sa...@gmail.com>
wrote:

> Hi Jun,
> Thanks for your comments. Please find the inline replies below.
>
> >605.2 It's rare for the follower to need the remote data. So, the current
> approach is fine too. Could you document the process of rebuilding the
> producer state since we can't simply trim the producerState to an offset in
> the middle of a segment.
>
> Will clarify in the KIP.
>
> >5102.2 Would it be clearer to make startPosiont long and endPosition of
> Optional<Long>?
>
> We will have arg checks with respective validation. It is not a good
> practice to have arguments with optional as mentioned here.
> https://rules.sonarsource.com/java/RSPEC-3553
>
>
> >5102.5 LogSegmentData still has leaderEpochIndex as File instead of
> ByteBuffer.
>
> Updated.
>
> >5102.7 Could you define all public methods for LogSegmentData?
>
> Updated.
>
> >5103.5 Could you change the reference to rlm_process_interval_ms and
> rlm_retry_interval_ms to the new config names? Also, the retry interval
> config seems still missing. It would be useful to support exponential
> backoff with the retry interval config.
>
> Good point. We wanted the retry with truncated exponential backoff,
> updated the KIP.
>
> >5111. "RLM follower fetches the earliest offset for the earliest leader
> epoch by calling RLMM.earliestLogOffset(TopicPartition topicPartition, int
> leaderEpoch) and updates that as the log start offset." This text is still
> there. Also, could we remove earliestLogOffset() from RLMM?
>
> Updated.
>
> >5115. There are still references to "remote log cleaners".
>
> Updated.
>
> >6000. Since we are returning new error codes, we need to bump up the
> protocol version for Fetch request. Also, it will be useful to document all
> new error codes and whether they are retriable or not.
>
> Sure, we will add that in the KIP.
>
> >6001. public Map<Long, Long> segmentLeaderEpochs(): Currently, leaderEpoch
> is int32 instead of long.
>
> Updated.
>
> >6002. Is RemoteLogSegmentMetadata.markedForDeletion() needed given
> RemoteLogSegmentMetadata.state()?
>
> No, it is fixed.
>
> >6003. RemoteLogSegmentMetadata remoteLogSegmentMetadata(TopicPartition
> topicPartition, long offset, int epochForOffset): Should this return
> Optional<RemoteLogSegmentMetadata>?
>
> That makes sense, updated.
>
> >6005. RemoteLogState: It seems it's better to split it between
> DeletePartitionUpdate and RemoteLogSegmentMetadataUpdate since the states
> are never shared between the two use cases.
>
> Agree with that, updated.
>
> >6006. RLMM.onPartitionLeadershipChanges(): This may be ok. However, is it
> ture that other than the metadata topic, RLMM just needs to know whether
> there is a replica assigned to this broker and doesn't need to know whether
> the replica is the leader or the follower?
>
> That may be true. If the implementation does not need that, it can
> ignore the information in the callback.
>
> >6007: "Handle expired remote segments (leader and follower)": Why is this
> needed in both the leader and the follower?
>
> Updated.
>
> >6008.       "name": "SegmentSizeInBytes",
>                 "type": "int64",
> The segment size can just be int32.
>
> Updated.
>
> >6009. For the record format in the log, it seems that we need to add
> record
> type and record version before the serialized bytes. We can follow the
> convention used in
>
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-631%3A+The+Quorum-based+Kafka+Controller#KIP631:TheQuorumbasedKafkaController-RecordFormats
>
> Yes, KIP already mentions that these are serialized before the payload
> as below. We will mention explicitly that these two are written before
> the data is written.
>
> RLMM instance on broker publishes the message to the topic with key as
> null and value with the below format.
>
> type      : unsigned var int, represents the value type. This value is
> 'apikey' as mentioned in the schema.
> version : unsigned var int, the 'version' number of the type as
> mentioned in the schema.
> data      : record payload in kafka protocol message format.
>
>
> >6010. remote.log.manager.thread.pool.size: The default value is 10. This
> might be too high when enabling the tiered feature for the first time.
> Since there are lots of segments that need to be tiered initially, a large
> number of threads could overwhelm the broker.
>
> Is the default value 5 reasonable?
>
> 6011. "The number of milli seconds to keep the local log segment before it
> gets deleted. If not set, the value in `log.retention.minutes` is used. If
> set to -1, no time limit is applied." We should use log.retention.ms
> instead of log.retention.minutes.
> Nice typo catch. Updated the KIP.
>
> Thanks,
> Satish.
>
> On Thu, Dec 3, 2020 at 8:03 AM Jun Rao <ju...@confluent.io> wrote:
> >
> > Hi, Satish,
> >
> > Thanks for the updated KIP. A few more comments below.
> >
> > 605.2 It's rare for the follower to need the remote data. So, the current
> > approach is fine too. Could you document the process of rebuilding the
> > producer state since we can't simply trim the producerState to an offset
> in
> > the middle of a segment.
> >
> > 5102.2 Would it be clearer to make startPosiont long and endPosition of
> > Optional<Long>?
> >
> > 5102.5 LogSegmentData still has leaderEpochIndex as File instead of
> > ByteBuffer.
> >
> > 5102.7 Could you define all public methods for LogSegmentData?
> >
> > 5103.5 Could you change the reference to rlm_process_interval_ms and
> > rlm_retry_interval_ms to the new config names? Also, the retry interval
> > config seems still missing. It would be useful to support exponential
> > backoff with the retry interval config.
> >
> > 5111. "RLM follower fetches the earliest offset for the earliest leader
> > epoch by calling RLMM.earliestLogOffset(TopicPartition topicPartition,
> int
> > leaderEpoch) and updates that as the log start offset." This text is
> still
> > there. Also, could we remove earliestLogOffset() from RLMM?
> >
> > 5115. There are still references to "remote log cleaners".
> >
> > 6000. Since we are returning new error codes, we need to bump up the
> > protocol version for Fetch request. Also, it will be useful to document
> all
> > new error codes and whether they are retriable or not.
> >
> > 6001. public Map<Long, Long> segmentLeaderEpochs(): Currently,
> leaderEpoch
> > is int32 instead of long.
> >
> > 6002. Is RemoteLogSegmentMetadata.markedForDeletion() needed given
> > RemoteLogSegmentMetadata.state()?
> >
> > 6003. RemoteLogSegmentMetadata remoteLogSegmentMetadata(TopicPartition
> > topicPartition, long offset, int epochForOffset): Should this return
> > Optional<RemoteLogSegmentMetadata>?
> >
> > 6004. DeletePartitionUpdate.epoch(): It would be useful to pick a more
> > indicative name so that people understand what epoch this is.
> >
> > 6005. RemoteLogState: It seems it's better to split it between
> > DeletePartitionUpdate and RemoteLogSegmentMetadataUpdate since the states
> > are never shared between the two use cases.
> >
> > 6006. RLMM.onPartitionLeadershipChanges(): This may be ok. However, is it
> > ture that other than the metadata topic, RLMM just needs to know whether
> > there is a replica assigned to this broker and doesn't need to know
> whether
> > the replica is the leader or the follower?
> >
> > 6007: "Handle expired remote segments (leader and follower)": Why is this
> > needed in both the leader and the follower?
> >
> > 6008.       "name": "SegmentSizeInBytes",
> >                 "type": "int64",
> > The segment size can just be int32.
> >
> > 6009. For the record format in the log, it seems that we need to add
> record
> > type and record version before the serialized bytes. We can follow the
> > convention used in
> >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-631%3A+The+Quorum-based+Kafka+Controller#KIP631:TheQuorumbasedKafkaController-RecordFormats
> > .
> >
> > 6010. remote.log.manager.thread.pool.size: The default value is 10. This
> > might be too high when enabling the tiered feature for the first time.
> > Since there are lots of segments that need to be tiered initially, a
> large
> > number of threads could overwhelm the broker.
> >
> > 6011. "The number of milli seconds to keep the local log segment before
> it
> > gets deleted. If not set, the value in `log.retention.minutes` is used.
> If
> > set to -1, no time limit is applied." We should use log.retention.ms
> > instead of log.retention.minutes.
> >
> > Jun
> >
> > On Tue, Dec 1, 2020 at 2:42 AM Satish Duggana <sa...@gmail.com>
> > wrote:
> >
> > > Hi,
> > > We updated the KIP with the points mentioned in the earlier mail
> > > except for KIP-516 related changes. You can go through them and let us
> > > know if you have any comments. We will update the KIP with the
> > > remaining todo items and KIP-516 related changes by end of this
> > > week(5th Dec).
> > >
> > > Thanks,
> > > Satish.
> > >
> > > On Tue, Nov 10, 2020 at 8:26 PM Satish Duggana <
> satish.duggana@gmail.com>
> > > wrote:
> > > >
> > > > Hi Jun,
> > > > Thanks for your comments. Please find the inline replies below.
> > > >
> > > > 605.2 "Build the local leader epoch cache by cutting the leader epoch
> > > > sequence received from remote storage to [LSO, ELO]." I mentioned an
> > > issue
> > > > earlier. Suppose the leader's local start offset is 100. The follower
> > > finds
> > > > a remote segment covering offset range [80, 120). The producerState
> with
> > > > this remote segment is up to offset 120. To trim the producerState to
> > > > offset 100 requires more work since one needs to download the
> previous
> > > > producerState up to offset 80 and then replay the messages from 80 to
> > > 100.
> > > > It seems that it's simpler in this case for the follower just to
> take the
> > > > remote segment as it is and start fetching from offset 120.
> > > >
> > > > We chose that approach to avoid any edge cases here. It may be
> > > > possible that the remote log segment that is received may not have
> the
> > > > same leader epoch sequence from 100-120 as it contains on the
> > > > leader(this can happen due to unclean leader). It is safe to start
> > > > from what the leader returns here.Another way is to find the remote
> > > > log segment
> > > >
> > > > 5016. Just to echo what Kowshik was saying. It seems that
> > > > RLMM.onPartitionLeadershipChanges() is only called on the replicas
> for a
> > > > partition, not on the replicas for the __remote_log_segment_metadata
> > > > partition. It's not clear how the leader of
> __remote_log_segment_metadata
> > > > obtains the metadata for remote segments for deletion.
> > > >
> > > > RLMM will always receive the callback for the remote log metadata
> > > > topic partitions hosted on the local broker and these will be
> > > > subscribed. I will make this clear in the KIP.
> > > >
> > > > 5100. KIP-516 has been accepted and is being implemented now. Could
> you
> > > > update the KIP based on topicID?
> > > >
> > > > We mentioned KIP-516 and how it helps. We will update this KIP with
> > > > all the changes it brings with KIP-516.
> > > >
> > > > 5101. RLMM: It would be useful to clarify how the following two APIs
> are
> > > > used. According to the wiki, the former is used for topic deletion
> and
> > > the
> > > > latter is used for retention. It seems that retention should use the
> > > former
> > > > since remote segments without a matching epoch in the leader
> (potentially
> > > > due to unclean leader election) also need to be garbage collected.
> The
> > > > latter seems to be used for the new leader to determine the last
> tiered
> > > > segment.
> > > >     default Iterator<RemoteLogSegmentMetadata>
> > > > listRemoteLogSegments(TopicPartition topicPartition)
> > > >     Iterator<RemoteLogSegmentMetadata>
> > > listRemoteLogSegments(TopicPartition
> > > > topicPartition, long leaderEpoch);
> > > >
> > > > Right,.that is what we are currently doing. We will update the
> > > > javadocs and wiki with that. Earlier, we did not want to remove the
> > > > segments which are not matched with leader epochs from the ladder
> > > > partition as they may be used later by a replica which can become a
> > > > leader (unclean leader election) and refer those segments. But that
> > > > may leak these segments in remote storage until the topic lifetime.
> We
> > > > decided to cleanup the segments with the oldest incase of size based
> > > > retention also.
> > > >
> > > > 5102. RSM:
> > > > 5102.1 For methods like fetchLogSegmentData(), it seems that they can
> > > > use RemoteLogSegmentId instead of RemoteLogSegmentMetadata.
> > > >
> > > > It will be useful to have metadata for RSM to fetch log segment. It
> > > > may create location/path using id with other metadata too.
> > > >
> > > > 5102.2 In fetchLogSegmentData(), should we use long instead of Long?
> > > >
> > > > Wanted to keep endPosition as optional to read till the end of the
> > > > segment and avoid sentinels.
> > > >
> > > > 5102.3 Why only some of the methods have default implementation and
> > > others
> > > > Don't?
> > > >
> > > > Actually,  RSM will not have any default implementations. Those 3
> > > > methods were made default earlier for tests etc. Updated the wiki.
> > > >
> > > > 5102.4. Could we define RemoteLogSegmentMetadataUpdate
> > > > and DeletePartitionUpdate?
> > > >
> > > > Sure, they will be added.
> > > >
> > > >
> > > > 5102.5 LogSegmentData: It seems that it's easier to pass
> > > > in leaderEpochIndex as a ByteBuffer or byte array than a file since
> it
> > > will
> > > > be generated in memory.
> > > >
> > > > Right, this is in plan.
> > > >
> > > > 5102.6 RemoteLogSegmentMetadata: It seems that it needs both
> baseOffset
> > > and
> > > > startOffset. For example, deleteRecords() could move the startOffset
> to
> > > the
> > > > middle of a segment. If we copy the full segment to remote storage,
> the
> > > > baseOffset and the startOffset will be different.
> > > >
> > > > Good point. startOffset is baseOffset by default, if not set
> explicitly.
> > > >
> > > > 5102.7 Could we define all the public methods for
> > > RemoteLogSegmentMetadata
> > > > and LogSegmentData?
> > > >
> > > > Sure, updated the wiki.
> > > >
> > > > 5102.8 Could we document whether endOffset in
> RemoteLogSegmentMetadata is
> > > > inclusive/exclusive?
> > > >
> > > > It is inclusive, will update.
> > > >
> > > > 5103. configs:
> > > > 5103.1 Could we define the default value of non-required configs
> (e.g the
> > > > size of new thread pools)?
> > > >
> > > > Sure, that makes sense.
> > > >
> > > > 5103.2 It seems that local.log.retention.ms should default to
> > > retention.ms,
> > > > instead of remote.log.retention.minutes. Similarly, it seems
> > > > that local.log.retention.bytes should default to segment.bytes.
> > > >
> > > > Right, we do not have  remote.log.retention as we discussed earlier.
> > > > Thanks for catching the typo.
> > > >
> > > > 5103.3 remote.log.manager.thread.pool.size: The description says
> "used in
> > > > scheduling tasks to copy segments, fetch remote log indexes and
> clean up
> > > > remote log segments". However, there is a separate
> > > > config remote.log.reader.threads for fetching remote data. It's
> weird to
> > > > fetch remote index and log in different thread pools since both are
> used
> > > > for serving fetch requests.
> > > >
> > > > Right, remote.log.manager.thread.pool is mainly used for copy/cleanup
> > > > activities. Fetch path always goes through remote.log.reader.threads.
> > > >
> > > > 5103.4 remote.log.manager.task.interval.ms: Is that the amount of
> time
> > > to
> > > > back off when there is no work to do? If so, perhaps it can be
> renamed as
> > > > backoff.ms.
> > > >
> > > > This is the delay interval for each iteration. It may be renamed to
> > > > remote.log.manager.task.delay.ms
> > > >
> > > > 5103.5 Are rlm_process_interval_ms and rlm_retry_interval_ms
> configs? If
> > > > so, they need to be listed in this section.
> > > >
> > > > remote.log.manager.task.interval.ms is the process internal, retry
> > > > interval is missing in the configs, which will be updated in the KIP.
> > > >
> > > > 5104. "RLM maintains a bounded cache(possibly LRU) of the index
> files of
> > > > remote log segments to avoid multiple index fetches from the remote
> > > > storage." Is the RLM in memory or on disk? If on disk, where is it
> > > stored?
> > > > Do we need a configuration to bound the size?
> > > >
> > > > It is stored on disk. They are stored in a directory
> > > > `remote-log-index-cache` under log dir. We plan to have a config for
> > > > that instead of default. We will have a configuration for that.
> > > >
> > > > 5105. The KIP uses local-log-start-offset and Earliest Local Offset
> in
> > > > different places. It would be useful to standardize the terminology.
> > > >
> > > > Sure.
> > > >
> > > > 5106. The section on "In BuildingRemoteLogAux state". It listed two
> > > options
> > > > without saying which option is chosen.
> > > > We already mentioned in the KIP that we chose option-2.
> > > >
> > > > 5107. Follower to leader transition: It has step 2, but not step 1.
> > > > Step-1 is there but it is not explicitly highlighted. It is previous
> > > > table to step-2.
> > > >
> > > > 5108. If a consumer fetches from the remote data and the remote
> storage
> > > is
> > > > not available, what error code is used in the fetch response?
> > > >
> > > > Good point. We have not yet defined the error for this case. We need
> > > > to define an error message and send the same in fetch response.
> > > >
> > > > 5109. "ListOffsets: For timestamps >= 0, it returns the first message
> > > > offset whose timestamp is >= to the given timestamp in the request.
> That
> > > > means it checks in remote log time indexes first, after which local
> log
> > > > time indexes are checked." Could you document which method in RLMM is
> > > used
> > > > for this?
> > > >
> > > > Okay.
> > > >
> > > > 5110. Stopreplica: "it sets all the remote log segment metadata of
> that
> > > > partition with a delete marker and publishes them to RLMM." This
> seems
> > > > outdated given the new topic deletion logic.
> > > >
> > > > Will update with KIP-516 related points.
> > > >
> > > > 5111. "RLM follower fetches the earliest offset for the earliest
> leader
> > > > epoch by calling RLMM.earliestLogOffset(TopicPartition
> topicPartition,
> > > int
> > > > leaderEpoch) and updates that as the log start offset." Do we need
> that
> > > > since replication propagates logStartOffset already?
> > > >
> > > > Good point. Right, existing replication protocol takes care of
> > > > updating the followers’s log start offset received from the leader.
> > > >
> > > > 5112. Is the default maxWaitMs of 500ms enough for fetching from
> remote
> > > > storage?
> > > >
> > > > Remote reads may fail within the current default wait time, but
> > > > subsequent fetches would be able to serve as that data is stored in
> > > > the local cache. This cache is currently implemented in RSMs. But we
> > > > plan to pull this into the remote log messaging layer in future.
> > > >
> > > > 5113. "Committed offsets can be stored in a local file to avoid
> reading
> > > the
> > > > messages again when a broker is restarted." Could you describe the
> format
> > > > and the location of the file? Also, could the same message be
> processed
> > > by
> > > > RLMM again after broker restart? If so, how do we handle that?
> > > >
> > > > Sure, we will update in the KIP.
> > > >
> > > > 5114. Message format
> > > > 5114.1 There are two records named RemoteLogSegmentMetadataRecord
> with
> > > > apiKey 0 and 1.
> > > >
> > > > Nice catch, that was a typo. Fixed in the wiki.
> > > >
> > > > 5114.2 RemoteLogSegmentMetadataRecord: Could we document whether
> > > endOffset
> > > > is inclusive/exclusive?
> > > > It is inclusive, will update.
> > > >
> > > > 5114.3 RemoteLogSegmentMetadataRecord: Could you explain LeaderEpoch
> a
> > > bit
> > > > more? Is that the epoch of the leader when it copies the segment to
> > > remote
> > > > storage? Also, how will this field be used?
> > > >
> > > > Right, this is the leader epoch of the broker which copied this
> > > > segment. This is helpful in reason about which broker copied the
> > > > segment to remote storage.
> > > >
> > > > 5114.4 EventTimestamp: Could you explain this a bit more? Each
> record in
> > > > Kafka already has a timestamp field. Could we just use that?
> > > >
> > > > This is the  timestamp at which  the respective event occurred. Added
> > > > this  to RemoteLogSegmentMetadata as RLMM can be  any other
> > > > implementation. We thought about that but it looked cleaner to use at
> > > > the message structure level instead of getting that from the consumer
> > > > record and using that to build the respective event.
> > > >
> > > >
> > > > 5114.5 SegmentSizeInBytes: Could this just be int32?
> > > >
> > > > Right, it looks like config allows only int value >= 14.
> > > >
> > > > 5115. RemoteLogCleaner(RLC): This could be confused with the log
> cleaner
> > > > for compaction. Perhaps it can be renamed to sth like
> > > > RemotePartitionRemover.
> > > >
> > > > I am fine with RemotePartitionRemover or RemoteLogDeletionManager(we
> > > > have other manager classes like RLM, RLMM).
> > > >
> > > > 5116. "RLC receives the delete_partition_marked and processes it if
> it is
> > > > not yet processed earlier." How does it know whether
> > > > delete_partition_marked has been processed earlier?
> > > >
> > > > This is to handle duplicate delete_partition_marked events. RLC
> > > > internally maintains a state for the delete_partition events and if
> it
> > > > already has an existing event then it ignores if it is already being
> > > > processed.
> > > >
> > > > 5117. Should we add a new MessageFormatter to read the tier metadata
> > > topic?
> > > >
> > > > Right, this is in plan but did not mention it in the KIP. This will
> be
> > > > useful for debugging purposes too.
> > > >
> > > > 5118. "Maximum remote log reader thread pool task queue size. If the
> task
> > > > queue is full, broker will stop reading remote log segments." What
> do we
> > > > return to the fetch request in this case?
> > > >
> > > > We return an error response for that partition.
> > > >
> > > > 5119. It would be useful to list all things not supported in the
> first
> > > > version in a Future work or Limitations section. For example,
> compacted
> > > > topic, JBOD, changing remote.log.storage.enable from true to false,
> etc.
> > > >
> > > > We already have a non-goals section which is filled with some of
> these
> > > > details. Do we need another limitations section?
> > > >
> > > > Thanks,
> > > > Satish.
> > > >
> > > > On Wed, Nov 4, 2020 at 11:27 PM Jun Rao <ju...@confluent.io> wrote:
> > > > >
> > > > > Hi, Satish,
> > > > >
> > > > > Thanks for the updated KIP. A few more comments below.
> > > > >
> > > > > 605.2 "Build the local leader epoch cache by cutting the leader
> epoch
> > > > > sequence received from remote storage to [LSO, ELO]." I mentioned
> an
> > > issue
> > > > > earlier. Suppose the leader's local start offset is 100. The
> follower
> > > finds
> > > > > a remote segment covering offset range [80, 120). The producerState
> > > with
> > > > > this remote segment is up to offset 120. To trim the producerState
> to
> > > > > offset 100 requires more work since one needs to download the
> previous
> > > > > producerState up to offset 80 and then replay the messages from 80
> to
> > > 100.
> > > > > It seems that it's simpler in this case for the follower just to
> take
> > > the
> > > > > remote segment as it is and start fetching from offset 120.
> > > > >
> > > > > 5016. Just to echo what Kowshik was saying. It seems that
> > > > > RLMM.onPartitionLeadershipChanges() is only called on the replicas
> for
> > > a
> > > > > partition, not on the replicas for the
> __remote_log_segment_metadata
> > > > > partition. It's not clear how the leader of
> > > __remote_log_segment_metadata
> > > > > obtains the metadata for remote segments for deletion.
> > > > >
> > > > > 5100. KIP-516 has been accepted and is being implemented now.
> Could you
> > > > > update the KIP based on topicID?
> > > > >
> > > > > 5101. RLMM: It would be useful to clarify how the following two
> APIs
> > > are
> > > > > used. According to the wiki, the former is used for topic deletion
> and
> > > the
> > > > > latter is used for retention. It seems that retention should use
> the
> > > former
> > > > > since remote segments without a matching epoch in the leader
> > > (potentially
> > > > > due to unclean leader election) also need to be garbage collected.
> The
> > > > > latter seems to be used for the new leader to determine the last
> tiered
> > > > > segment.
> > > > >     default Iterator<RemoteLogSegmentMetadata>
> > > > > listRemoteLogSegments(TopicPartition topicPartition)
> > > > >     Iterator<RemoteLogSegmentMetadata>
> > > listRemoteLogSegments(TopicPartition
> > > > > topicPartition, long leaderEpoch);
> > > > >
> > > > > 5102. RSM:
> > > > > 5102.1 For methods like fetchLogSegmentData(), it seems that they
> can
> > > > > use RemoteLogSegmentId instead of RemoteLogSegmentMetadata.
> > > > > 5102.2 In fetchLogSegmentData(), should we use long instead of
> Long?
> > > > > 5102.3 Why only some of the methods have default implementation and
> > > others
> > > > > don't?
> > > > > 5102.4. Could we define RemoteLogSegmentMetadataUpdate
> > > > > and DeletePartitionUpdate?
> > > > > 5102.5 LogSegmentData: It seems that it's easier to pass
> > > > > in leaderEpochIndex as a ByteBuffer or byte array than a file
> since it
> > > will
> > > > > be generated in memory.
> > > > > 5102.6 RemoteLogSegmentMetadata: It seems that it needs both
> > > baseOffset and
> > > > > startOffset. For example, deleteRecords() could move the
> startOffset
> > > to the
> > > > > middle of a segment. If we copy the full segment to remote
> storage, the
> > > > > baseOffset and the startOffset will be different.
> > > > > 5102.7 Could we define all the public methods for
> > > RemoteLogSegmentMetadata
> > > > > and LogSegmentData?
> > > > > 5102.8 Could we document whether endOffset in
> RemoteLogSegmentMetadata
> > > is
> > > > > inclusive/exclusive?
> > > > >
> > > > > 5103. configs:
> > > > > 5103.1 Could we define the default value of non-required configs
> (e.g
> > > the
> > > > > size of new thread pools)?
> > > > > 5103.2 It seems that local.log.retention.ms should default to
> > > retention.ms,
> > > > > instead of remote.log.retention.minutes. Similarly, it seems
> > > > > that local.log.retention.bytes should default to segment.bytes.
> > > > > 5103.3 remote.log.manager.thread.pool.size: The description says
> "used
> > > in
> > > > > scheduling tasks to copy segments, fetch remote log indexes and
> clean
> > > up
> > > > > remote log segments". However, there is a separate
> > > > > config remote.log.reader.threads for fetching remote data. It's
> weird
> > > to
> > > > > fetch remote index and log in different thread pools since both are
> > > used
> > > > > for serving fetch requests.
> > > > > 5103.4 remote.log.manager.task.interval.ms: Is that the amount of
> > > time to
> > > > > back off when there is no work to do? If so, perhaps it can be
> renamed
> > > as
> > > > > backoff.ms.
> > > > > 5103.5 Are rlm_process_interval_ms and rlm_retry_interval_ms
> configs?
> > > If
> > > > > so, they need to be listed in this section.
> > > > >
> > > > > 5104. "RLM maintains a bounded cache(possibly LRU) of the index
> files
> > > of
> > > > > remote log segments to avoid multiple index fetches from the remote
> > > > > storage." Is the RLM in memory or on disk? If on disk, where is it
> > > stored?
> > > > > Do we need a configuration to bound the size?
> > > > >
> > > > > 5105. The KIP uses local-log-start-offset and Earliest Local
> Offset in
> > > > > different places. It would be useful to standardize the
> terminology.
> > > > >
> > > > > 5106. The section on "In BuildingRemoteLogAux state". It listed two
> > > options
> > > > > without saying which option is chosen.
> > > > >
> > > > > 5107. Follower to leader transition: It has step 2, but not step 1.
> > > > >
> > > > > 5108. If a consumer fetches from the remote data and the remote
> > > storage is
> > > > > not available, what error code is used in the fetch response?
> > > > >
> > > > > 5109. "ListOffsets: For timestamps >= 0, it returns the first
> message
> > > > > offset whose timestamp is >= to the given timestamp in the request.
> > > That
> > > > > means it checks in remote log time indexes first, after which
> local log
> > > > > time indexes are checked." Could you document which method in RLMM
> is
> > > used
> > > > > for this?
> > > > >
> > > > > 5110. Stopreplica: "it sets all the remote log segment metadata of
> that
> > > > > partition with a delete marker and publishes them to RLMM." This
> seems
> > > > > outdated given the new topic deletion logic.
> > > > >
> > > > > 5111. "RLM follower fetches the earliest offset for the earliest
> leader
> > > > > epoch by calling RLMM.earliestLogOffset(TopicPartition
> topicPartition,
> > > int
> > > > > leaderEpoch) and updates that as the log start offset." Do we need
> that
> > > > > since replication propagates logStartOffset already?
> > > > >
> > > > > 5112. Is the default maxWaitMs of 500ms enough for fetching from
> remote
> > > > > storage?
> > > > >
> > > > > 5113. "Committed offsets can be stored in a local file to avoid
> > > reading the
> > > > > messages again when a broker is restarted." Could you describe the
> > > format
> > > > > and the location of the file? Also, could the same message be
> > > processed by
> > > > > RLMM again after broker restart? If so, how do we handle that?
> > > > >
> > > > > 5114. Message format
> > > > > 5114.1 There are two records named RemoteLogSegmentMetadataRecord
> with
> > > > > apiKey 0 and 1.
> > > > > 5114.2 RemoteLogSegmentMetadataRecord: Could we document whether
> > > endOffset
> > > > > is inclusive/exclusive?
> > > > > 5114.3 RemoteLogSegmentMetadataRecord: Could you explain
> LeaderEpoch a
> > > bit
> > > > > more? Is that the epoch of the leader when it copies the segment to
> > > remote
> > > > > storage? Also, how will this field be used?
> > > > > 5114.4 EventTimestamp: Could you explain this a bit more? Each
> record
> > > in
> > > > > Kafka already has a timestamp field. Could we just use that?
> > > > > 5114.5 SegmentSizeInBytes: Could this just be int32?
> > > > >
> > > > > 5115. RemoteLogCleaner(RLC): This could be confused with the log
> > > cleaner
> > > > > for compaction. Perhaps it can be renamed to sth like
> > > > > RemotePartitionRemover.
> > > > >
> > > > > 5116. "RLC receives the delete_partition_marked and processes it
> if it
> > > is
> > > > > not yet processed earlier." How does it know whether
> > > > > delete_partition_marked has been processed earlier?
> > > > >
> > > > > 5117. Should we add a new MessageFormatter to read the tier
> metadata
> > > topic?
> > > > >
> > > > > 5118. "Maximum remote log reader thread pool task queue size. If
> the
> > > task
> > > > > queue is full, broker will stop reading remote log segments." What
> do
> > > we
> > > > > return to the fetch request in this case?
> > > > >
> > > > > 5119. It would be useful to list all things not supported in the
> first
> > > > > version in a Future work or Limitations section. For example,
> compacted
> > > > > topic, JBOD, changing remote.log.storage.enable from true to false,
> > > etc.
> > > > >
> > > > > Thanks,
> > > > >
> > > > > Jun
> > > > >
> > > > > On Tue, Oct 27, 2020 at 5:57 PM Kowshik Prakasam <
> > > kprakasam@confluent.io>
> > > > > wrote:
> > > > >
> > > > > > Hi Satish,
> > > > > >
> > > > > > Thanks for the updates to the KIP. Here are my first batch of
> > > > > > comments/suggestions on the latest version of the KIP.
> > > > > >
> > > > > > 5012. In the RemoteStorageManager interface, there is an API
> defined
> > > for
> > > > > > each file type. For example, fetchOffsetIndex,
> fetchTimestampIndex
> > > etc. To
> > > > > > avoid the duplication, I'd suggest we can instead have a FileType
> > > enum and
> > > > > > a common get API based on the FileType.
> > > > > >
> > > > > > 5013. There are some references to the Google doc in the KIP. I
> > > wasn't sure
> > > > > > if the Google doc is expected to be in sync with the contents of
> the
> > > wiki.
> > > > > > Going forward, it seems easier if just the KIP is maintained as
> the
> > > source
> > > > > > of truth. In this regard, could you please move all the
> references
> > > to the
> > > > > > Google doc, maybe to a separate References section at the bottom
> of
> > > the
> > > > > > KIP?
> > > > > >
> > > > > > 5014. There are some TODO sections in the KIP. Would these be
> filled
> > > up in
> > > > > > future iterations?
> > > > > >
> > > > > > 5015. Under "Topic deletion lifecycle", I'm trying to understand
> why
> > > do we
> > > > > > need delete_partition_marked as well as the
> delete_partition_started
> > > > > > messages. I couldn't spot a drawback if supposing we simplified
> the
> > > design
> > > > > > such that the controller would only write
> delete_partition_started
> > > message,
> > > > > > and RemoteLogCleaner (RLC) instance picks it up for processing.
> What
> > > am I
> > > > > > missing?
> > > > > >
> > > > > > 5016. Under "Topic deletion lifecycle", step (4) is mentioned as
> > > "RLC gets
> > > > > > all the remote log segments for the partition and each of these
> > > remote log
> > > > > > segments is deleted with the next steps.". Since the RLC instance
> > > runs on
> > > > > > each tier topic partition leader, how does the RLC then get the
> list
> > > of
> > > > > > remote log segments to be deleted? It will be useful to add that
> > > detail to
> > > > > > the KIP.
> > > > > >
> > > > > > 5017. Under "Public Interfaces -> Configs", there is a line
> > > mentioning "We
> > > > > > will support flipping remote.log.storage.enable in next
> versions."
> > > It will
> > > > > > be useful to mention this in the "Future Work" section of the KIP
> > > too.
> > > > > >
> > > > > > 5018. The KIP introduces a number of configuration parameters. It
> > > will be
> > > > > > useful to mention in the KIP if the user should assume these as
> > > static
> > > > > > configuration in the server.properties file, or dynamic
> > > configuration which
> > > > > > can be modified without restarting the broker.
> > > > > >
> > > > > > 5019.  Maybe this is planned as a future update to the KIP, but I
> > > thought
> > > > > > I'd mention it here. Could you please add details to the KIP on
> why
> > > RocksDB
> > > > > > was chosen as the default cache implementation of RLMM, and how
> it
> > > is going
> > > > > > to be used? Were alternatives compared/considered? For example,
> it
> > > would be
> > > > > > useful to explain/evaluate the following: 1) debuggability of the
> > > RocksDB
> > > > > > JNI interface, 2) performance, 3) portability across platforms
> and 4)
> > > > > > interface parity of RocksDB’s JNI api with it's underlying C/C++
> api.
> > > > > >
> > > > > > 5020. Following up on (5019), for the RocksDB cache, it will be
> > > useful to
> > > > > > explain the relationship/mapping between the following in the
> KIP:
> > > 1) # of
> > > > > > tiered partitions, 2) # of partitions of metadata topic
> > > > > > __remote_log_metadata and 3) # of RocksDB instances. i.e. is the
> > > plan to
> > > > > > have a RocksDB instance per tiered partition, or per metadata
> topic
> > > > > > partition, or just 1 for per broker?
> > > > > >
> > > > > > 5021. I was looking at the implementation prototype (PR link:
> > > > > > https://github.com/apache/kafka/pull/7561). It seems that a
> boolean
> > > > > > attribute is being introduced into the Log layer to check if
> remote
> > > log
> > > > > > capability is enabled. While the boolean footprint is small at
> the
> > > moment,
> > > > > > this can easily grow in the future and become harder to
> > > > > > test/maintain, considering that the Log layer is already pretty
> > > complex. We
> > > > > > should start thinking about how to manage such changes to the Log
> > > layer
> > > > > > (for the purpose of improved testability, better separation of
> > > concerns and
> > > > > > readability). One proposal I have is to take a step back and
> define a
> > > > > > higher level Log interface. Then, the Broker code can be changed
> to
> > > use
> > > > > > this interface. It can be changed such that only a handle to the
> > > interface
> > > > > > is exposed to other components (such as LogCleaner,
> ReplicaManager
> > > etc.)
> > > > > > and not the underlying Log object. This approach keeps the user
> of
> > > the Log
> > > > > > layer agnostic of the whereabouts of the data. Underneath the
> > > interface,
> > > > > > the implementing classes can completely separate local log
> > > capabilities
> > > > > > from the remote log. For example, the Log class can be
> simplified to
> > > only
> > > > > > manage logic surrounding local log segments and metadata.
> > > Additionally, a
> > > > > > wrapper class can be provided (implementing the higher level Log
> > > interface)
> > > > > > which will contain any/all logic surrounding tiered data. The
> wrapper
> > > > > > class will wrap around an instance of the Log class delegating
> the
> > > local
> > > > > > log logic to it. Finally, a handle to the wrapper class can be
> > > exposed to
> > > > > > the other components wherever they need a handle to the higher
> level
> > > Log
> > > > > > interface.
> > > > > >
> > > > > >
> > > > > > Cheers,
> > > > > > Kowshik
> > > > > >
> > > > > > On Mon, Oct 26, 2020 at 9:52 PM Satish Duggana <
> > > satish.duggana@gmail.com>
> > > > > > wrote:
> > > > > >
> > > > > > > Hi,
> > > > > > > KIP is updated with 1) topic deletion lifecycle and its related
> > > items
> > > > > > > 2) Protocol changes(mainly related to ListOffsets) and other
> minor
> > > > > > > changes.
> > > > > > > Please go through them and let us know your comments.
> > > > > > >
> > > > > > > Thanks,
> > > > > > > Satish.
> > > > > > >
> > > > > > > On Mon, Sep 28, 2020 at 9:10 PM Satish Duggana <
> > > satish.duggana@gmail.com
> > > > > > >
> > > > > > > wrote:
> > > > > > > >
> > > > > > > > Hi Dhruvil,
> > > > > > > > Thanks for looking into the KIP and sending your comments.
> Sorry
> > > for
> > > > > > > > the late reply, missed it in the mail thread.
> > > > > > > >
> > > > > > > > 1. Could you describe how retention would work with this KIP
> and
> > > which
> > > > > > > > threads are responsible for driving this work? I believe
> there
> > > are 3
> > > > > > > kinds
> > > > > > > > of retention processes we are looking at:
> > > > > > > >   (a) Regular retention for data in tiered storage as per
> > > configured `
> > > > > > > > retention.ms` / `retention.bytes`.
> > > > > > > >   (b) Local retention for data in local storage as per
> > > configured `
> > > > > > > > local.log.retention.ms` / `local.log.retention.bytes`
> > > > > > > >   (c) Possibly regular retention for data in local storage,
> if
> > > the
> > > > > > > tiering
> > > > > > > > task is lagging or for data that is below the log start
> offset.
> > > > > > > >
> > > > > > > > Local log retention is done by the existing log cleanup
> tasks.
> > > These
> > > > > > > > are not done for segments that are not yet copied to remote
> > > storage.
> > > > > > > > Remote log cleanup is done by the leader partition’s RLMTask.
> > > > > > > >
> > > > > > > > 2. When does a segment become eligible to be tiered? Is it as
> > > soon as
> > > > > > the
> > > > > > > > segment is rolled and the end offset is less than the last
> stable
> > > > > > offset
> > > > > > > as
> > > > > > > > mentioned in the KIP? I wonder if we need to consider other
> > > parameters
> > > > > > > too,
> > > > > > > > like the highwatermark so that we are guaranteed that what
> we are
> > > > > > tiering
> > > > > > > > has been committed to the log and accepted by the ISR.
> > > > > > > >
> > > > > > > > AFAIK, last stable offset is always <= highwatermark. This
> will
> > > make
> > > > > > > > sure we are always tiering the message segments which have
> been
> > > > > > > > accepted by ISR and transactionally completed.
> > > > > > > >
> > > > > > > >
> > > > > > > > 3. The section on "Follower Fetch Scenarios" is useful but
> is a
> > > bit
> > > > > > > > difficult to parse at the moment. It would be useful to
> > > summarize the
> > > > > > > > changes we need in the ReplicaFetcher.
> > > > > > > >
> > > > > > > > It may become difficult for users to read/follow if we add
> code
> > > changes
> > > > > > > here.
> > > > > > > >
> > > > > > > > 4. Related to the above, it's a bit unclear how we are
> planning
> > > on
> > > > > > > > restoring the producer state for a new replica. Could you
> expand
> > > on
> > > > > > that?
> > > > > > > >
> > > > > > > > It is mentioned in the KIP BuildingRemoteLogAuxState is
> > > introduced to
> > > > > > > > build the state like leader epoch sequence and producer
> snapshots
> > > > > > > > before it starts fetching the data from the leader. We will
> make
> > > it
> > > > > > > > clear in the KIP.
> > > > > > > >
> > > > > > > >
> > > > > > > > 5. Similarly, it would be worth summarizing the behavior on
> > > unclean
> > > > > > > leader
> > > > > > > > election. There are several scenarios to consider here: data
> > > loss from
> > > > > > > > local log, data loss from remote log, data loss from metadata
> > > topic,
> > > > > > etc.
> > > > > > > > It's worth describing these in detail.
> > > > > > > >
> > > > > > > > We mentioned the cases about unclean leader election in the
> > > follower
> > > > > > > > fetch scenarios.
> > > > > > > > If there are errors while fetching data from remote store or
> > > metadata
> > > > > > > > store, it will work the same way as it works with local log.
> It
> > > > > > > > returns the error back to the caller. Please let us know if
> I am
> > > > > > > > missing your point here.
> > > > > > > >
> > > > > > > >
> > > > > > > > 7. For a READ_COMMITTED FetchRequest, how do we retrieve and
> > > return the
> > > > > > > > aborted transaction metadata?
> > > > > > > >
> > > > > > > > When a fetch for a remote log is accessed, we will fetch
> aborted
> > > > > > > > transactions along with the segment if it is not found in the
> > > local
> > > > > > > > index cache. This includes the case of transaction index not
> > > existing
> > > > > > > > in the remote log segment. That means, the cache entry can be
> > > empty or
> > > > > > > > have a list of aborted transactions.
> > > > > > > >
> > > > > > > >
> > > > > > > > 8. The `LogSegmentData` class assumes that we have a log
> segment,
> > > > > > offset
> > > > > > > > index, time index, transaction index, producer snapshot and
> > > leader
> > > > > > epoch
> > > > > > > > index. How do we deal with cases where we do not have one or
> > > more of
> > > > > > > these?
> > > > > > > > For example, we may not have a transaction index or producer
> > > snapshot
> > > > > > > for a
> > > > > > > > particular segment. The former is optional, and the latter is
> > > only kept
> > > > > > > for
> > > > > > > > up to the 3 latest segments.
> > > > > > > >
> > > > > > > > This is a good point,  we discussed this in the last meeting.
> > > > > > > > Transaction index is optional and we will copy them only if
> it
> > > exists.
> > > > > > > > We want to keep all the producer snapshots at each log
> segment
> > > rolling
> > > > > > > > and they can be removed if the log copying is successful and
> it
> > > still
> > > > > > > > maintains the existing latest 3 segments, We only delete the
> > > producer
> > > > > > > > snapshots which have been copied to remote log segments on
> > > leader.
> > > > > > > > Follower will keep the log segments beyond the segments which
> > > have not
> > > > > > > > been copied to remote storage. We will update the KIP with
> these
> > > > > > > > details.
> > > > > > > >
> > > > > > > > Thanks,
> > > > > > > > Satish.
> > > > > > > >
> > > > > > > > On Thu, Sep 17, 2020 at 1:47 AM Dhruvil Shah <
> > > dhruvil@confluent.io>
> > > > > > > wrote:
> > > > > > > > >
> > > > > > > > > Hi Satish, Harsha,
> > > > > > > > >
> > > > > > > > > Thanks for the KIP. Few questions below:
> > > > > > > > >
> > > > > > > > > 1. Could you describe how retention would work with this
> KIP
> > > and
> > > > > > which
> > > > > > > > > threads are responsible for driving this work? I believe
> there
> > > are 3
> > > > > > > kinds
> > > > > > > > > of retention processes we are looking at:
> > > > > > > > >   (a) Regular retention for data in tiered storage as per
> > > configured
> > > > > > `
> > > > > > > > > retention.ms` / `retention.bytes`.
> > > > > > > > >   (b) Local retention for data in local storage as per
> > > configured `
> > > > > > > > > local.log.retention.ms` / `local.log.retention.bytes`
> > > > > > > > >   (c) Possibly regular retention for data in local
> storage, if
> > > the
> > > > > > > tiering
> > > > > > > > > task is lagging or for data that is below the log start
> offset.
> > > > > > > > >
> > > > > > > > > 2. When does a segment become eligible to be tiered? Is it
> as
> > > soon as
> > > > > > > the
> > > > > > > > > segment is rolled and the end offset is less than the last
> > > stable
> > > > > > > offset as
> > > > > > > > > mentioned in the KIP? I wonder if we need to consider other
> > > > > > parameters
> > > > > > > too,
> > > > > > > > > like the highwatermark so that we are guaranteed that what
> we
> > > are
> > > > > > > tiering
> > > > > > > > > has been committed to the log and accepted by the ISR.
> > > > > > > > >
> > > > > > > > > 3. The section on "Follower Fetch Scenarios" is useful but
> is
> > > a bit
> > > > > > > > > difficult to parse at the moment. It would be useful to
> > > summarize the
> > > > > > > > > changes we need in the ReplicaFetcher.
> > > > > > > > >
> > > > > > > > > 4. Related to the above, it's a bit unclear how we are
> > > planning on
> > > > > > > > > restoring the producer state for a new replica. Could you
> > > expand on
> > > > > > > that?
> > > > > > > > >
> > > > > > > > > 5. Similarly, it would be worth summarizing the behavior on
> > > unclean
> > > > > > > leader
> > > > > > > > > election. There are several scenarios to consider here:
> data
> > > loss
> > > > > > from
> > > > > > > > > local log, data loss from remote log, data loss from
> metadata
> > > topic,
> > > > > > > etc.
> > > > > > > > > It's worth describing these in detail.
> > > > > > > > >
> > > > > > > > > 6. It would be useful to add details about how we plan on
> using
> > > > > > > RocksDB in
> > > > > > > > > the default implementation of `RemoteLogMetadataManager`.
> > > > > > > > >
> > > > > > > > > 7. For a READ_COMMITTED FetchRequest, how do we retrieve
> and
> > > return
> > > > > > the
> > > > > > > > > aborted transaction metadata?
> > > > > > > > >
> > > > > > > > > 8. The `LogSegmentData` class assumes that we have a log
> > > segment,
> > > > > > > offset
> > > > > > > > > index, time index, transaction index, producer snapshot and
> > > leader
> > > > > > > epoch
> > > > > > > > > index. How do we deal with cases where we do not have one
> or
> > > more of
> > > > > > > these?
> > > > > > > > > For example, we may not have a transaction index or
> producer
> > > snapshot
> > > > > > > for a
> > > > > > > > > particular segment. The former is optional, and the latter
> is
> > > only
> > > > > > > kept for
> > > > > > > > > up to the 3 latest segments.
> > > > > > > > >
> > > > > > > > > Thanks,
> > > > > > > > > Dhruvil
> > > > > > > > >
> > > > > > > > > On Mon, Sep 7, 2020 at 6:54 PM Harsha Ch <
> harsha.ch@gmail.com>
> > > > > > wrote:
> > > > > > > > >
> > > > > > > > > > Hi All,
> > > > > > > > > >
> > > > > > > > > > We are all working through the last meeting feedback.
> I'll
> > > cancel
> > > > > > the
> > > > > > > > > > tomorrow 's meeting and we can meanwhile continue our
> > > discussion in
> > > > > > > mailing
> > > > > > > > > > list. We can start the regular meeting from next week
> > > onwards.
> > > > > > > > > >
> > > > > > > > > > Thanks,
> > > > > > > > > >
> > > > > > > > > > Harsha
> > > > > > > > > >
> > > > > > > > > > On Fri, Sep 04, 2020 at 8:41 AM, Satish Duggana <
> > > > > > > satish.duggana@gmail.com
> > > > > > > > > > > wrote:
> > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > Hi Jun,
> > > > > > > > > > > Thanks for your thorough review and comments. Please
> find
> > > the
> > > > > > > inline
> > > > > > > > > > > replies below.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > 600. The topic deletion logic needs more details.
> > > > > > > > > > > 600.1 The KIP mentions "The controller considers the
> topic
> > > > > > > partition is
> > > > > > > > > > > deleted only when it determines that there are no log
> > > segments
> > > > > > for
> > > > > > > that
> > > > > > > > > > > topic partition by using RLMM". How is this done?
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > It uses RLMM#listSegments() returns all the segments
> for
> > > the
> > > > > > given
> > > > > > > topic
> > > > > > > > > > > partition.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > 600.2 "If the delete option is enabled then the leader
> > > will stop
> > > > > > > RLM task
> > > > > > > > > > > and stop processing and it sets all the remote log
> segment
> > > > > > > metadata of
> > > > > > > > > > > that partition with a delete marker and publishes them
> to
> > > RLMM."
> > > > > > We
> > > > > > > > > > > discussed this earlier. When a topic is being deleted,
> > > there may
> > > > > > > not be a
> > > > > > > > > > > leader for the deleted partition.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > This is a good point. As suggested in the meeting, we
> will
> > > add a
> > > > > > > separate
> > > > > > > > > > > section for topic/partition deletion lifecycle and this
> > > scenario
> > > > > > > will be
> > > > > > > > > > > addressed.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > 601. Unclean leader election
> > > > > > > > > > > 601.1 Scenario 1: new empty follower
> > > > > > > > > > > After step 1, the follower restores up to offset 3. So
> why
> > > does
> > > > > > it
> > > > > > > have
> > > > > > > > > > > LE-2 <https://issues.apache.org/jira/browse/LE-2> at
> > > offset 5?
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > Nice catch. It was showing the leader epoch fetched
> from
> > > the
> > > > > > remote
> > > > > > > > > > > storage. It should be shown with the truncated till
> offset
> > > 3.
> > > > > > > Updated the
> > > > > > > > > > > KIP.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > 601.2 senario 5: After Step 3, leader A has
> inconsistent
> > > data
> > > > > > > between its
> > > > > > > > > > > local and the tiered data. For example. offset 3 has
> msg 3
> > > LE-0
> > > > > > > <https://issues.apache.org/jira/browse/LE-0> locally,
> > > > > > > > > > > but msg 5 LE-1 <
> https://issues.apache.org/jira/browse/LE-1>
> > > in
> > > > > > > the remote store. While it's ok for the unclean leader
> > > > > > > > > > > to lose data, it should still return consistent data,
> > > whether
> > > > > > it's
> > > > > > > from
> > > > > > > > > > > the local or the remote store.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > There is no inconsistency here as LE-0
> > > > > > > <https://issues.apache.org/jira/browse/LE-0> offsets are [0,
> 4]
> > > and LE-2
> > > > > > > <https://issues.apache.org/jira/browse/LE-2>:
> > > > > > > > > > > [5, ]. It will always get the right records for the
> given
> > > offset
> > > > > > > and
> > > > > > > > > > > leader epoch. In case of remote, RSM is invoked to get
> the
> > > remote
> > > > > > > log
> > > > > > > > > > > segment that contains the given offset with the leader
> > > epoch.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > 601.4 It seems that retention is based on
> > > > > > > > > > > listRemoteLogSegments(TopicPartition topicPartition,
> long
> > > > > > > leaderEpoch).
> > > > > > > > > > > When there is an unclean leader election, it's possible
> > > for the
> > > > > > new
> > > > > > > > > > leader
> > > > > > > > > > > to not to include certain epochs in its epoch cache.
> How
> > > are
> > > > > > remote
> > > > > > > > > > > segments associated with those epochs being cleaned?
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > That is a good point. This leader will also cleanup the
> > > epochs
> > > > > > > earlier to
> > > > > > > > > > > its start leader epoch and delete those segments. It
> gets
> > > the
> > > > > > > earliest
> > > > > > > > > > > epoch for a partition and starts deleting segments from
> > > that
> > > > > > leader
> > > > > > > > > > epoch.
> > > > > > > > > > > We need one more API in RLMM to get the earliest leader
> > > epoch.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > 601.5 The KIP discusses the handling of unclean leader
> > > elections
> > > > > > > for user
> > > > > > > > > > > topics. What about unclean leader elections on
> > > > > > > > > > > __remote_log_segment_metadata?
> > > > > > > > > > > This is the same as other system topics like
> > > consumer_offsets,
> > > > > > > > > > > __transaction_state topics. As discussed in the
> meeting,
> > > we will
> > > > > > > add the
> > > > > > > > > > > behavior of __remote_log_segment_metadata topic’s
> unclean
> > > leader
> > > > > > > > > > > truncation.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > 602. It would be useful to clarify the limitations in
> the
> > > initial
> > > > > > > > > > release.
> > > > > > > > > > > The KIP mentions not supporting compacted topics. What
> > > about JBOD
> > > > > > > and
> > > > > > > > > > > changing the configuration of a topic from delete to
> > > compact
> > > > > > after
> > > > > > > > > > remote.
> > > > > > > > > > > log. storage. enable (
> http://remote.log.storage.enable/
> > > ) is
> > > > > > > enabled?
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > This was updated in the KIP earlier.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > 603. RLM leader tasks:
> > > > > > > > > > > 603.1"It checks for rolled over LogSegments (which have
> > > the last
> > > > > > > message
> > > > > > > > > > > offset less than last stable offset of that topic
> > > partition) and
> > > > > > > copies
> > > > > > > > > > > them along with their offset/time/transaction indexes
> and
> > > leader
> > > > > > > epoch
> > > > > > > > > > > cache to the remote tier." It needs to copy the
> producer
> > > snapshot
> > > > > > > too.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > Right. It copies producer snapshots too as mentioned in
> > > > > > > LogSegmentData.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > 603.2 "Local logs are not cleaned up till those
> segments
> > > are
> > > > > > copied
> > > > > > > > > > > successfully to remote even though their retention
> > > time/size is
> > > > > > > reached"
> > > > > > > > > > > This seems weird. If the tiering stops because the
> remote
> > > store
> > > > > > is
> > > > > > > not
> > > > > > > > > > > available, we don't want the local data to grow
> forever.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > It was clarified in the discussion that the comment was
> > > more
> > > > > > about
> > > > > > > the
> > > > > > > > > > > local storage goes beyond the log.retention. The above
> > > statement
> > > > > > > is about
> > > > > > > > > > > local.log.retention but not for the complete
> > > log.retention. When
> > > > > > it
> > > > > > > > > > > reaches the log.retention then it will delete the local
> > > logs even
> > > > > > > though
> > > > > > > > > > > those are not copied to remote storage.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > 604. "RLM maintains a bounded cache(possibly LRU) of
> the
> > > index
> > > > > > > files of
> > > > > > > > > > > remote log segments to avoid multiple index fetches
> from
> > > the
> > > > > > remote
> > > > > > > > > > > storage. These indexes can be used in the same way as
> local
> > > > > > segment
> > > > > > > > > > > indexes are used." Could you provide more details on
> this?
> > > Are
> > > > > > the
> > > > > > > > > > indexes
> > > > > > > > > > > cached in memory or on disk? If on disk, where are they
> > > stored?
> > > > > > > Are the
> > > > > > > > > > > cached indexes bound by a certain size?
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > These are cached on disk and stored in log.dir with a
> name
> > > > > > > > > > > “__remote_log_index_cache”. They are bound by the total
> > > size.
> > > > > > This
> > > > > > > will
> > > > > > > > > > be
> > > > > > > > > > > exposed as a user configuration,
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > 605. BuildingRemoteLogAux
> > > > > > > > > > > 605.1 In this section, two options are listed. Which
> one is
> > > > > > chosen?
> > > > > > > > > > > Option-2, updated the KIP.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > 605.2 In option 2, it says "Build the local leader
> epoch
> > > cache by
> > > > > > > cutting
> > > > > > > > > > > the leader epoch sequence received from remote storage
> to
> > > [LSO,
> > > > > > > ELO].
> > > > > > > > > > (LSO
> > > > > > > > > > >
> > > > > > > > > > > = log start offset)." We need to do the same thing for
> the
> > > > > > producer
> > > > > > > > > > > snapshot. However, it's hard to cut the producer
> snapshot
> > > to an
> > > > > > > earlier
> > > > > > > > > > > offset. Another option is to simply take the lastOffset
> > > from the
> > > > > > > remote
> > > > > > > > > > > segment and use that as the starting fetch offset in
> the
> > > > > > follower.
> > > > > > > This
> > > > > > > > > > > avoids the need for cutting.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > Right, this was mentioned in the “transactional
> support”
> > > section
> > > > > > > about
> > > > > > > > > > > adding these details.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > 606. ListOffsets: Since we need a version bump, could
> you
> > > > > > document
> > > > > > > it
> > > > > > > > > > > under a protocol change section?
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > Sure, we will update the KIP.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > 607. "LogStartOffset of a topic can point to either of
> > > local
> > > > > > > segment or
> > > > > > > > > > > remote segment but it is initialised and maintained in
> the
> > > Log
> > > > > > > class like
> > > > > > > > > > > now. This is already maintained in `Log` class while
> > > loading the
> > > > > > > logs and
> > > > > > > > > > > it can also be fetched from RemoteLogMetadataManager."
> > > What will
> > > > > > > happen
> > > > > > > > > > to
> > > > > > > > > > > the existing logic (e.g. log recovery) that currently
> > > depends on
> > > > > > > > > > > logStartOffset but assumes it's local?
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > They use a field called localLogStartOffset which is
> the
> > > local
> > > > > > log
> > > > > > > start
> > > > > > > > > > > offset..
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > 608. Handle expired remote segment: How does it pick
> up new
> > > > > > > > > > logStartOffset
> > > > > > > > > > > from deleteRecords?
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > Good point. This was not addressed in the KIP. Will
> update
> > > the
> > > > > > KIP
> > > > > > > on how
> > > > > > > > > > > the RLM task handles this scenario.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > 609. RLMM message format:
> > > > > > > > > > > 609.1 It includes both MaxTimestamp and EventTimestamp.
> > > Where
> > > > > > does
> > > > > > > it get
> > > > > > > > > > > both since the message in the log only contains one
> > > timestamp?
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > `EventTimeStamp` is the timestamp at which that segment
> > > metadata
> > > > > > > event is
> > > > > > > > > > > generated. This is more for audits.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > 609.2 If we change just the state (e.g. to
> > > DELETE_STARTED), it
> > > > > > > seems it's
> > > > > > > > > > > wasteful to have to include all other fields not
> changed.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > This is a good point. We thought about incremental
> > > updates. But
> > > > > > we
> > > > > > > want
> > > > > > > > > > to
> > > > > > > > > > > make sure all the events are in the expected order and
> take
> > > > > > action
> > > > > > > based
> > > > > > > > > > > on the latest event. Will think through the approaches
> in
> > > detail
> > > > > > > and
> > > > > > > > > > > update here.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > 609.3 Could you document which process makes the
> following
> > > > > > > transitions
> > > > > > > > > > > DELETE_MARKED, DELETE_STARTED, DELETE_FINISHED?
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > Okay, will document more details.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > 610. remote.log.reader.max.pending.tasks: "Maximum
> remote
> > > log
> > > > > > > reader
> > > > > > > > > > > thread pool task queue size. If the task queue is full,
> > > broker
> > > > > > > will stop
> > > > > > > > > > > reading remote log segments." What does the broker do
> if
> > > the
> > > > > > queue
> > > > > > > is
> > > > > > > > > > > full?
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > It returns an error for this topic partition.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > 611. What do we return if the request offset/epoch
> doesn't
> > > exist
> > > > > > > in the
> > > > > > > > > > > following API?
> > > > > > > > > > > RemoteLogSegmentMetadata
> > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > > > topicPartition, long offset, int epochForOffset)
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > This returns null. But we prefer to update the return
> type
> > > as
> > > > > > > Optional
> > > > > > > > > > and
> > > > > > > > > > > return Empty if that does not exist.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > Thanks,
> > > > > > > > > > > Satish.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > On Tue, Sep 1, 2020 at 9:45 AM Jun Rao < jun@
> confluent.
> > > io (
> > > > > > > > > > > jun@confluent.io ) > wrote:
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > >>
> > > > > > > > > > >>
> > > > > > > > > > >> Hi, Satish,
> > > > > > > > > > >>
> > > > > > > > > > >>
> > > > > > > > > > >>
> > > > > > > > > > >> Thanks for the updated KIP. Made another pass. A few
> more
> > > > > > comments
> > > > > > > > > > below.
> > > > > > > > > > >>
> > > > > > > > > > >>
> > > > > > > > > > >>
> > > > > > > > > > >> 600. The topic deletion logic needs more details.
> > > > > > > > > > >> 600.1 The KIP mentions "The controller considers the
> topic
> > > > > > > partition is
> > > > > > > > > > >> deleted only when it determines that there are no log
> > > segments
> > > > > > > for that
> > > > > > > > > > >> topic partition by using RLMM". How is this done?
> 600.2
> > > "If the
> > > > > > > delete
> > > > > > > > > > >> option is enabled then the leader will stop RLM task
> and
> > > stop
> > > > > > > processing
> > > > > > > > > > >> and it sets all the remote log segment metadata of
> that
> > > > > > partition
> > > > > > > with a
> > > > > > > > > > >> delete marker and publishes them to RLMM." We
> discussed
> > > this
> > > > > > > earlier.
> > > > > > > > > > When
> > > > > > > > > > >> a topic is being deleted, there may not be a leader
> for
> > > the
> > > > > > > deleted
> > > > > > > > > > >> partition.
> > > > > > > > > > >>
> > > > > > > > > > >>
> > > > > > > > > > >>
> > > > > > > > > > >> 601. Unclean leader election
> > > > > > > > > > >> 601.1 Scenario 1: new empty follower
> > > > > > > > > > >> After step 1, the follower restores up to offset 3. So
> > > why does
> > > > > > > it have
> > > > > > > > > > >> LE-2 <https://issues.apache.org/jira/browse/LE-2> at
> > > offset 5?
> > > > > > > > > > >> 601.2 senario 5: After Step 3, leader A has
> inconsistent
> > > data
> > > > > > > between
> > > > > > > > > > its
> > > > > > > > > > >> local and the tiered data. For example. offset 3 has
> msg
> > > 3 LE-0
> > > > > > > <https://issues.apache.org/jira/browse/LE-0> locally,
> > > > > > > > > > >> but msg 5 LE-1 <
> > > https://issues.apache.org/jira/browse/LE-1> in
> > > > > > > the remote store. While it's ok for the unclean leader
> > > > > > > > > > >> to lose data, it should still return consistent data,
> > > whether
> > > > > > > it's from
> > > > > > > > > > >> the local or the remote store.
> > > > > > > > > > >> 601.3 The follower picks up log start offset using the
> > > following
> > > > > > > api.
> > > > > > > > > > >> Suppose that we have 3 remote segments (LE,
> > > SegmentStartOffset)
> > > > > > > as (2,
> > > > > > > > > > >> 10),
> > > > > > > > > > >> (3, 20) and (7, 15) due to an unclean leader election.
> > > Using the
> > > > > > > > > > following
> > > > > > > > > > >> api will cause logStartOffset to go backward from 20
> to
> > > 15. How
> > > > > > > do we
> > > > > > > > > > >> prevent that?
> > > > > > > > > > >> earliestLogOffset(TopicPartition topicPartition, int
> > > > > > leaderEpoch)
> > > > > > > 601.4
> > > > > > > > > > It
> > > > > > > > > > >> seems that retention is based on
> > > > > > > > > > >> listRemoteLogSegments(TopicPartition topicPartition,
> long
> > > > > > > leaderEpoch).
> > > > > > > > > > >> When there is an unclean leader election, it's
> possible
> > > for the
> > > > > > > new
> > > > > > > > > > leader
> > > > > > > > > > >> to not to include certain epochs in its epoch cache.
> How
> > > are
> > > > > > > remote
> > > > > > > > > > >> segments associated with those epochs being cleaned?
> > > 601.5 The
> > > > > > KIP
> > > > > > > > > > >> discusses the handling of unclean leader elections for
> > > user
> > > > > > > topics. What
> > > > > > > > > > >> about unclean leader elections on
> > > > > > > > > > >> __remote_log_segment_metadata?
> > > > > > > > > > >>
> > > > > > > > > > >>
> > > > > > > > > > >>
> > > > > > > > > > >> 602. It would be useful to clarify the limitations in
> the
> > > > > > initial
> > > > > > > > > > release.
> > > > > > > > > > >> The KIP mentions not supporting compacted topics. What
> > > about
> > > > > > JBOD
> > > > > > > and
> > > > > > > > > > >> changing the configuration of a topic from delete to
> > > compact
> > > > > > after
> > > > > > > > > > remote.
> > > > > > > > > > >> log. storage. enable (
> http://remote.log.storage.enable/
> > > ) is
> > > > > > > enabled?
> > > > > > > > > > >>
> > > > > > > > > > >>
> > > > > > > > > > >>
> > > > > > > > > > >> 603. RLM leader tasks:
> > > > > > > > > > >> 603.1"It checks for rolled over LogSegments (which
> have
> > > the last
> > > > > > > message
> > > > > > > > > > >> offset less than last stable offset of that topic
> > > partition) and
> > > > > > > copies
> > > > > > > > > > >> them along with their offset/time/transaction indexes
> and
> > > leader
> > > > > > > epoch
> > > > > > > > > > >> cache to the remote tier." It needs to copy the
> producer
> > > > > > snapshot
> > > > > > > too.
> > > > > > > > > > >> 603.2 "Local logs are not cleaned up till those
> segments
> > > are
> > > > > > > copied
> > > > > > > > > > >> successfully to remote even though their retention
> > > time/size is
> > > > > > > reached"
> > > > > > > > > > >> This seems weird. If the tiering stops because the
> remote
> > > store
> > > > > > > is not
> > > > > > > > > > >> available, we don't want the local data to grow
> forever.
> > > > > > > > > > >>
> > > > > > > > > > >>
> > > > > > > > > > >>
> > > > > > > > > > >> 604. "RLM maintains a bounded cache(possibly LRU) of
> the
> > > index
> > > > > > > files of
> > > > > > > > > > >> remote log segments to avoid multiple index fetches
> from
> > > the
> > > > > > > remote
> > > > > > > > > > >> storage. These indexes can be used in the same way as
> > > local
> > > > > > > segment
> > > > > > > > > > >> indexes are used." Could you provide more details on
> > > this? Are
> > > > > > the
> > > > > > > > > > indexes
> > > > > > > > > > >> cached in memory or on disk? If on disk, where are
> they
> > > stored?
> > > > > > > Are the
> > > > > > > > > > >> cached indexes bound by a certain size?
> > > > > > > > > > >>
> > > > > > > > > > >>
> > > > > > > > > > >>
> > > > > > > > > > >> 605. BuildingRemoteLogAux
> > > > > > > > > > >> 605.1 In this section, two options are listed. Which
> one
> > > is
> > > > > > > chosen?
> > > > > > > > > > 605.2
> > > > > > > > > > >> In option 2, it says "Build the local leader epoch
> cache
> > > by
> > > > > > > cutting the
> > > > > > > > > > >> leader epoch sequence received from remote storage to
> > > [LSO,
> > > > > > ELO].
> > > > > > > (LSO
> > > > > > > > > > >> = log start offset)." We need to do the same thing
> for the
> > > > > > > producer
> > > > > > > > > > >> snapshot. However, it's hard to cut the producer
> snapshot
> > > to an
> > > > > > > earlier
> > > > > > > > > > >> offset. Another option is to simply take the
> lastOffset
> > > from the
> > > > > > > remote
> > > > > > > > > > >> segment and use that as the starting fetch offset in
> the
> > > > > > > follower. This
> > > > > > > > > > >> avoids the need for cutting.
> > > > > > > > > > >>
> > > > > > > > > > >>
> > > > > > > > > > >>
> > > > > > > > > > >> 606. ListOffsets: Since we need a version bump, could
> you
> > > > > > > document it
> > > > > > > > > > >> under a protocol change section?
> > > > > > > > > > >>
> > > > > > > > > > >>
> > > > > > > > > > >>
> > > > > > > > > > >> 607. "LogStartOffset of a topic can point to either of
> > > local
> > > > > > > segment or
> > > > > > > > > > >> remote segment but it is initialised and maintained in
> > > the Log
> > > > > > > class
> > > > > > > > > > like
> > > > > > > > > > >> now. This is already maintained in `Log` class while
> > > loading the
> > > > > > > logs
> > > > > > > > > > and
> > > > > > > > > > >> it can also be fetched from RemoteLogMetadataManager."
> > > What will
> > > > > > > happen
> > > > > > > > > > to
> > > > > > > > > > >> the existing logic (e.g. log recovery) that currently
> > > depends on
> > > > > > > > > > >> logStartOffset but assumes it's local?
> > > > > > > > > > >>
> > > > > > > > > > >>
> > > > > > > > > > >>
> > > > > > > > > > >> 608. Handle expired remote segment: How does it pick
> up
> > > new
> > > > > > > > > > logStartOffset
> > > > > > > > > > >> from deleteRecords?
> > > > > > > > > > >>
> > > > > > > > > > >>
> > > > > > > > > > >>
> > > > > > > > > > >> 609. RLMM message format:
> > > > > > > > > > >> 609.1 It includes both MaxTimestamp and
> EventTimestamp.
> > > Where
> > > > > > > does it
> > > > > > > > > > get
> > > > > > > > > > >> both since the message in the log only contains one
> > > timestamp?
> > > > > > > 609.2 If
> > > > > > > > > > we
> > > > > > > > > > >> change just the state (e.g. to DELETE_STARTED), it
> seems
> > > it's
> > > > > > > wasteful
> > > > > > > > > > to
> > > > > > > > > > >> have to include all other fields not changed. 609.3
> Could
> > > you
> > > > > > > document
> > > > > > > > > > >> which process makes the following transitions
> > > DELETE_MARKED,
> > > > > > > > > > >> DELETE_STARTED, DELETE_FINISHED?
> > > > > > > > > > >>
> > > > > > > > > > >>
> > > > > > > > > > >>
> > > > > > > > > > >> 610. remote.log.reader.max.pending.tasks: "Maximum
> remote
> > > log
> > > > > > > reader
> > > > > > > > > > >> thread pool task queue size. If the task queue is
> full,
> > > broker
> > > > > > > will stop
> > > > > > > > > > >> reading remote log segments." What does the broker do
> if
> > > the
> > > > > > > queue is
> > > > > > > > > > >> full?
> > > > > > > > > > >>
> > > > > > > > > > >>
> > > > > > > > > > >>
> > > > > > > > > > >> 611. What do we return if the request offset/epoch
> > > doesn't exist
> > > > > > > in the
> > > > > > > > > > >> following API?
> > > > > > > > > > >> RemoteLogSegmentMetadata
> > > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > > >> topicPartition, long offset, int epochForOffset)
> > > > > > > > > > >>
> > > > > > > > > > >>
> > > > > > > > > > >>
> > > > > > > > > > >> Jun
> > > > > > > > > > >>
> > > > > > > > > > >>
> > > > > > > > > > >>
> > > > > > > > > > >> On Mon, Aug 31, 2020 at 11:19 AM Satish Duggana <
> satish.
> > > > > > duggana@
> > > > > > > > > > gmail. com
> > > > > > > > > > >> ( satish.duggana@gmail.com ) > wrote:
> > > > > > > > > > >>
> > > > > > > > > > >>
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>> KIP is updated with
> > > > > > > > > > >>> - Remote log segment metadata topic message
> > > format/schema.
> > > > > > > > > > >>> - Added remote log segment metadata state
> transitions and
> > > > > > > explained how
> > > > > > > > > > >>> the deletion of segments is handled, including the
> case
> > > of
> > > > > > > partition
> > > > > > > > > > >>> deletions.
> > > > > > > > > > >>> - Added a few more limitations in the "Non goals"
> > > section.
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>> Thanks,
> > > > > > > > > > >>> Satish.
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>> On Thu, Aug 27, 2020 at 12:42 AM Harsha Ch < harsha.
> ch@
> > > > > > gmail.
> > > > > > > com (
> > > > > > > > > > >>> harsha.ch@gmail.com ) > wrote:
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>> Updated the KIP with Meeting Notes section
> > > > > > > > > > >>>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>> https:/ / cwiki. apache. org/ confluence/ display/
> KAFKA/
> > > > > > > > > > KIP-405 <https://issues.apache.org/jira/browse/KIP-405>
> > > > > > > %3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> > > > > > > > > > >>> (
> > > > > > > > > > >>>
> > > > > > > > > >
> > > > > > >
> > > > > >
> > >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-405%3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> > > > > > > > > > >>> )
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>> On Tue, Aug 25, 2020 at 1:03 PM Jun Rao < jun@
> > > confluent. io
> > > > > > (
> > > > > > > > > > >>>> jun@confluent.io ) > wrote:
> > > > > > > > > > >>>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>> Hi, Harsha,
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>> Thanks for the summary. Could you add the summary
> and
> > > the
> > > > > > > recording
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>> link to
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>> the last section of
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>> https:/ / cwiki. apache. org/ confluence/ display/
> KAFKA/
> > > > > > > > > > Kafka+Improvement+Proposals
> > > > > > > > > > >>> (
> > > > > > > > > > >>>
> > > > > > > > > >
> > > > > > >
> > > > > >
> > >
> https://cwiki.apache.org/confluence/display/KAFKA/Kafka+Improvement+Proposals
> > > > > > > > > > >>> )
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>> ?
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>> Jun
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>> On Tue, Aug 25, 2020 at 11:12 AM Harsha
> Chintalapani <
> > > kafka@
> > > > > > > > > > harsha. io (
> > > > > > > > > > >>>>> kafka@harsha.io ) > wrote:
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>> Thanks everyone for attending the meeting today.
> > > > > > > > > > >>>>>> Here is the recording
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>> https:/ / drive. google. com/ file/ d/
> > > > > > > > > > 14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/ view?usp=sharing
> > > > > > > > > > >>> (
> > > > > > > > > > >>>
> > > > > > > > > >
> > > > > > >
> > > > > >
> > >
> https://drive.google.com/file/d/14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/view?usp=sharing
> > > > > > > > > > >>> )
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>> Notes:
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>> 1. KIP is updated with follower fetch protocol and
> > > ready to
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>> reviewed
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>> 2. Satish to capture schema of internal metadata
> > > topic in
> > > > > > the
> > > > > > > KIP
> > > > > > > > > > >>>>>> 3. We will update the KIP with details of
> different
> > > cases
> > > > > > > > > > >>>>>> 4. Test plan will be captured in a doc and will
> add
> > > to the
> > > > > > KIP
> > > > > > > > > > >>>>>> 5. Add a section "Limitations" to capture the
> > > capabilities
> > > > > > > that
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>> will
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>> be
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>> introduced with this KIP and what will not be
> covered
> > > in
> > > > > > this
> > > > > > > KIP.
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>> Please add to it I missed anything. Will produce a
> > > formal
> > > > > > > meeting
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>> notes
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>> from next meeting onwards.
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>> Thanks,
> > > > > > > > > > >>>>>> Harsha
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>> On Mon, Aug 24, 2020 at 9:42 PM, Ying Zheng <
> yingz@
> > > uber.
> > > > > > > com.
> > > > > > > > > > invalid (
> > > > > > > > > > >>>>>> yingz@uber.com.invalid ) > wrote:
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> We did some basic feature tests at Uber. The test
> > > cases and
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>> results are
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> shared in this google doc:
> > > > > > > > > > >>>>>>> https:/ / docs. google. com/ spreadsheets/ d/ (
> > > > > > > > > > >>>>>>> https://docs.google.com/spreadsheets/d/ )
> > > > > > > > > > >>>>>>>
> > > > > > 1XhNJqjzwXvMCcAOhEH0sSXU6RTvyoSf93DHF-YMfGLk/edit?usp=sharing
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> The performance test results were already shared
> in
> > > the KIP
> > > > > > > last
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>> month.
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> On Mon, Aug 24, 2020 at 11:10 AM Harsha Ch <
> harsha.
> > > ch@
> > > > > > > gmail.
> > > > > > > > > > com (
> > > > > > > > > > >>>>>>> harsha.ch@gmail.com ) >
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>> wrote:
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> "Understand commitments towards driving design &
> > > > > > > implementation of
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>> the
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>> KIP
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> further and how it aligns with participant
> interests
> > > in
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>> contributing to
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>> the
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> efforts (ex: in the context of Uber’s Q3/Q4
> > > roadmap)." What
> > > > > > > is that
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>> about?
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> On Mon, Aug 24, 2020 at 11:05 AM Kowshik
> Prakasam <
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>> kprakasam@ confluent. io ( kprakasam@confluent.io
> ) >
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> wrote:
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> Hi Harsha,
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> The following google doc contains a proposal for
> > > temporary
> > > > > > > agenda
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>> for
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>> the
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> KIP-405 <
> > > https://issues.apache.org/jira/browse/KIP-405> <
> > > > > > > https:/ / issues. apache. org/ jira/ browse/ KIP-405
> > > > > > > <https://issues.apache.org/jira/browse/KIP-405> (
> > > > > > > > > > >>>>>>> https://issues.apache.org/jira/browse/KIP-405 )
> >
> > > sync
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>> meeting
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> tomorrow:
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> https:/ / docs. google. com/ document/ d/ (
> > > > > > > > > > >>>>>>> https://docs.google.com/document/d/ )
> > > > > > > > > > >>>>>>> 1pqo8X5LU8TpwfC_iqSuVPezhfCfhGkbGN2TqiPA3LBU/edit
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> .
> > > > > > > > > > >>>>>>> Please could you add it to the Google calendar
> > > invite?
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> Thank you.
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> Cheers,
> > > > > > > > > > >>>>>>> Kowshik
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> On Thu, Aug 20, 2020 at 10:58 AM Harsha Ch <
> harsha.
> > > ch@
> > > > > > > gmail.
> > > > > > > > > > com (
> > > > > > > > > > >>>>>>> harsha.ch@gmail.com ) >
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>> wrote:
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> Hi All,
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> Scheduled a meeting for Tuesday 9am - 10am. I can
> > > record
> > > > > > and
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>> upload for
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> community to be able to follow the discussion.
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> Jun, please add the required folks on confluent
> side.
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> Thanks,
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> Harsha
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> On Thu, Aug 20, 2020 at 12:33 AM, Alexandre
> Dupriez <
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>> alexandre.dupriez@
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> gmail. com ( http://gmail.com/ ) > wrote:
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> Hi Jun,
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> Many thanks for your initiative.
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> If you like, I am happy to attend at the time you
> > > > > > suggested.
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> Many thanks,
> > > > > > > > > > >>>>>>> Alexandre
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> Le mer. 19 août 2020 à 22:00, Harsha Ch <
> harsha. ch@
> > > > > > > gmail. com (
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>> harsha.
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> ch@ gmail. com ( ch@gmail.com ) ) > a écrit :
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> Hi Jun,
> > > > > > > > > > >>>>>>> Thanks. This will help a lot. Tuesday will work
> for
> > > us.
> > > > > > > > > > >>>>>>> -Harsha
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> On Wed, Aug 19, 2020 at 1:24 PM Jun Rao < jun@
> > > confluent.
> > > > > > > io (
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>> jun@
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> confluent. io ( http://confluent.io/ ) ) >
> wrote:
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> Hi, Satish, Ying, Harsha,
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> Do you think it would be useful to have a regular
> > > virtual
> > > > > > > meeting
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>> to
> > > > > > > > > > >>>
> > > > > > > > > > >>>
> > > > > > > > > > >>>>
> > > > > > > > > > >>>>>
> > > > > > > > > > >>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> discuss this KIP? The goal of the meeting will be
> > > sharing
> > > > > > > > > > >>>>>>> design/development progress and discussing any
> open
> > > issues
> > > > > > to
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> accelerate
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> this KIP. If so, will every Tuesday (from next
> week)
> > > > > > 9am-10am
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> PT
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> work for you? I can help set up a Zoom meeting,
> > > invite
> > > > > > > everyone who
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> might
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> be interested, have it recorded and shared, etc.
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> Thanks,
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> Jun
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> On Tue, Aug 18, 2020 at 11:01 AM Satish Duggana <
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> satish. duggana@ gmail. com ( satish. duggana@
> > > gmail. com
> > > > > > (
> > > > > > > > > > >>>>>>> satish.duggana@gmail.com ) ) >
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> wrote:
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> Hi Kowshik,
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> Thanks for looking into the KIP and sending your
> > > comments.
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>>
> > > > > > > > > > >>>>>>> 5001. Under the section "Follower fetch protocol
> in
> > > > > > detail",
> > > > > > > the
> > > > > > > > > > >>>>>>> next-local-offset is the offset upto which the
> > > segments are
> > > > > > > copied
> > > > > > > > > > >>>>>>>
> > > > > > >
> > >
> > >
>

Re: [DISCUSS] KIP-405: Kafka Tiered Storage

[Satish Duggana <sa...@gmail.com>]

Hi Jun,
Thanks for your comments. Please find the inline replies below.

>605.2 It's rare for the follower to need the remote data. So, the current
approach is fine too. Could you document the process of rebuilding the
producer state since we can't simply trim the producerState to an offset in
the middle of a segment.

Will clarify in the KIP.

>5102.2 Would it be clearer to make startPosiont long and endPosition of
Optional<Long>?

We will have arg checks with respective validation. It is not a good
practice to have arguments with optional as mentioned here.
https://rules.sonarsource.com/java/RSPEC-3553


>5102.5 LogSegmentData still has leaderEpochIndex as File instead of
ByteBuffer.

Updated.

>5102.7 Could you define all public methods for LogSegmentData?

Updated.

>5103.5 Could you change the reference to rlm_process_interval_ms and
rlm_retry_interval_ms to the new config names? Also, the retry interval
config seems still missing. It would be useful to support exponential
backoff with the retry interval config.

Good point. We wanted the retry with truncated exponential backoff,
updated the KIP.

>5111. "RLM follower fetches the earliest offset for the earliest leader
epoch by calling RLMM.earliestLogOffset(TopicPartition topicPartition, int
leaderEpoch) and updates that as the log start offset." This text is still
there. Also, could we remove earliestLogOffset() from RLMM?

Updated.

>5115. There are still references to "remote log cleaners".

Updated.

>6000. Since we are returning new error codes, we need to bump up the
protocol version for Fetch request. Also, it will be useful to document all
new error codes and whether they are retriable or not.

Sure, we will add that in the KIP.

>6001. public Map<Long, Long> segmentLeaderEpochs(): Currently, leaderEpoch
is int32 instead of long.

Updated.

>6002. Is RemoteLogSegmentMetadata.markedForDeletion() needed given
RemoteLogSegmentMetadata.state()?

No, it is fixed.

>6003. RemoteLogSegmentMetadata remoteLogSegmentMetadata(TopicPartition
topicPartition, long offset, int epochForOffset): Should this return
Optional<RemoteLogSegmentMetadata>?

That makes sense, updated.

>6005. RemoteLogState: It seems it's better to split it between
DeletePartitionUpdate and RemoteLogSegmentMetadataUpdate since the states
are never shared between the two use cases.

Agree with that, updated.

>6006. RLMM.onPartitionLeadershipChanges(): This may be ok. However, is it
ture that other than the metadata topic, RLMM just needs to know whether
there is a replica assigned to this broker and doesn't need to know whether
the replica is the leader or the follower?

That may be true. If the implementation does not need that, it can
ignore the information in the callback.

>6007: "Handle expired remote segments (leader and follower)": Why is this
needed in both the leader and the follower?

Updated.

>6008.       "name": "SegmentSizeInBytes",
                "type": "int64",
The segment size can just be int32.

Updated.

>6009. For the record format in the log, it seems that we need to add record
type and record version before the serialized bytes. We can follow the
convention used in
https://cwiki.apache.org/confluence/display/KAFKA/KIP-631%3A+The+Quorum-based+Kafka+Controller#KIP631:TheQuorumbasedKafkaController-RecordFormats

Yes, KIP already mentions that these are serialized before the payload
as below. We will mention explicitly that these two are written before
the data is written.

RLMM instance on broker publishes the message to the topic with key as
null and value with the below format.

type      : unsigned var int, represents the value type. This value is
'apikey' as mentioned in the schema.
version : unsigned var int, the 'version' number of the type as
mentioned in the schema.
data      : record payload in kafka protocol message format.


>6010. remote.log.manager.thread.pool.size: The default value is 10. This
might be too high when enabling the tiered feature for the first time.
Since there are lots of segments that need to be tiered initially, a large
number of threads could overwhelm the broker.

Is the default value 5 reasonable?

6011. "The number of milli seconds to keep the local log segment before it
gets deleted. If not set, the value in `log.retention.minutes` is used. If
set to -1, no time limit is applied." We should use log.retention.ms
instead of log.retention.minutes.
Nice typo catch. Updated the KIP.

Thanks,
Satish.

On Thu, Dec 3, 2020 at 8:03 AM Jun Rao <ju...@confluent.io> wrote:
>
> Hi, Satish,
>
> Thanks for the updated KIP. A few more comments below.
>
> 605.2 It's rare for the follower to need the remote data. So, the current
> approach is fine too. Could you document the process of rebuilding the
> producer state since we can't simply trim the producerState to an offset in
> the middle of a segment.
>
> 5102.2 Would it be clearer to make startPosiont long and endPosition of
> Optional<Long>?
>
> 5102.5 LogSegmentData still has leaderEpochIndex as File instead of
> ByteBuffer.
>
> 5102.7 Could you define all public methods for LogSegmentData?
>
> 5103.5 Could you change the reference to rlm_process_interval_ms and
> rlm_retry_interval_ms to the new config names? Also, the retry interval
> config seems still missing. It would be useful to support exponential
> backoff with the retry interval config.
>
> 5111. "RLM follower fetches the earliest offset for the earliest leader
> epoch by calling RLMM.earliestLogOffset(TopicPartition topicPartition, int
> leaderEpoch) and updates that as the log start offset." This text is still
> there. Also, could we remove earliestLogOffset() from RLMM?
>
> 5115. There are still references to "remote log cleaners".
>
> 6000. Since we are returning new error codes, we need to bump up the
> protocol version for Fetch request. Also, it will be useful to document all
> new error codes and whether they are retriable or not.
>
> 6001. public Map<Long, Long> segmentLeaderEpochs(): Currently, leaderEpoch
> is int32 instead of long.
>
> 6002. Is RemoteLogSegmentMetadata.markedForDeletion() needed given
> RemoteLogSegmentMetadata.state()?
>
> 6003. RemoteLogSegmentMetadata remoteLogSegmentMetadata(TopicPartition
> topicPartition, long offset, int epochForOffset): Should this return
> Optional<RemoteLogSegmentMetadata>?
>
> 6004. DeletePartitionUpdate.epoch(): It would be useful to pick a more
> indicative name so that people understand what epoch this is.
>
> 6005. RemoteLogState: It seems it's better to split it between
> DeletePartitionUpdate and RemoteLogSegmentMetadataUpdate since the states
> are never shared between the two use cases.
>
> 6006. RLMM.onPartitionLeadershipChanges(): This may be ok. However, is it
> ture that other than the metadata topic, RLMM just needs to know whether
> there is a replica assigned to this broker and doesn't need to know whether
> the replica is the leader or the follower?
>
> 6007: "Handle expired remote segments (leader and follower)": Why is this
> needed in both the leader and the follower?
>
> 6008.       "name": "SegmentSizeInBytes",
>                 "type": "int64",
> The segment size can just be int32.
>
> 6009. For the record format in the log, it seems that we need to add record
> type and record version before the serialized bytes. We can follow the
> convention used in
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-631%3A+The+Quorum-based+Kafka+Controller#KIP631:TheQuorumbasedKafkaController-RecordFormats
> .
>
> 6010. remote.log.manager.thread.pool.size: The default value is 10. This
> might be too high when enabling the tiered feature for the first time.
> Since there are lots of segments that need to be tiered initially, a large
> number of threads could overwhelm the broker.
>
> 6011. "The number of milli seconds to keep the local log segment before it
> gets deleted. If not set, the value in `log.retention.minutes` is used. If
> set to -1, no time limit is applied." We should use log.retention.ms
> instead of log.retention.minutes.
>
> Jun
>
> On Tue, Dec 1, 2020 at 2:42 AM Satish Duggana <sa...@gmail.com>
> wrote:
>
> > Hi,
> > We updated the KIP with the points mentioned in the earlier mail
> > except for KIP-516 related changes. You can go through them and let us
> > know if you have any comments. We will update the KIP with the
> > remaining todo items and KIP-516 related changes by end of this
> > week(5th Dec).
> >
> > Thanks,
> > Satish.
> >
> > On Tue, Nov 10, 2020 at 8:26 PM Satish Duggana <sa...@gmail.com>
> > wrote:
> > >
> > > Hi Jun,
> > > Thanks for your comments. Please find the inline replies below.
> > >
> > > 605.2 "Build the local leader epoch cache by cutting the leader epoch
> > > sequence received from remote storage to [LSO, ELO]." I mentioned an
> > issue
> > > earlier. Suppose the leader's local start offset is 100. The follower
> > finds
> > > a remote segment covering offset range [80, 120). The producerState with
> > > this remote segment is up to offset 120. To trim the producerState to
> > > offset 100 requires more work since one needs to download the previous
> > > producerState up to offset 80 and then replay the messages from 80 to
> > 100.
> > > It seems that it's simpler in this case for the follower just to take the
> > > remote segment as it is and start fetching from offset 120.
> > >
> > > We chose that approach to avoid any edge cases here. It may be
> > > possible that the remote log segment that is received may not have the
> > > same leader epoch sequence from 100-120 as it contains on the
> > > leader(this can happen due to unclean leader). It is safe to start
> > > from what the leader returns here.Another way is to find the remote
> > > log segment
> > >
> > > 5016. Just to echo what Kowshik was saying. It seems that
> > > RLMM.onPartitionLeadershipChanges() is only called on the replicas for a
> > > partition, not on the replicas for the __remote_log_segment_metadata
> > > partition. It's not clear how the leader of __remote_log_segment_metadata
> > > obtains the metadata for remote segments for deletion.
> > >
> > > RLMM will always receive the callback for the remote log metadata
> > > topic partitions hosted on the local broker and these will be
> > > subscribed. I will make this clear in the KIP.
> > >
> > > 5100. KIP-516 has been accepted and is being implemented now. Could you
> > > update the KIP based on topicID?
> > >
> > > We mentioned KIP-516 and how it helps. We will update this KIP with
> > > all the changes it brings with KIP-516.
> > >
> > > 5101. RLMM: It would be useful to clarify how the following two APIs are
> > > used. According to the wiki, the former is used for topic deletion and
> > the
> > > latter is used for retention. It seems that retention should use the
> > former
> > > since remote segments without a matching epoch in the leader (potentially
> > > due to unclean leader election) also need to be garbage collected. The
> > > latter seems to be used for the new leader to determine the last tiered
> > > segment.
> > >     default Iterator<RemoteLogSegmentMetadata>
> > > listRemoteLogSegments(TopicPartition topicPartition)
> > >     Iterator<RemoteLogSegmentMetadata>
> > listRemoteLogSegments(TopicPartition
> > > topicPartition, long leaderEpoch);
> > >
> > > Right,.that is what we are currently doing. We will update the
> > > javadocs and wiki with that. Earlier, we did not want to remove the
> > > segments which are not matched with leader epochs from the ladder
> > > partition as they may be used later by a replica which can become a
> > > leader (unclean leader election) and refer those segments. But that
> > > may leak these segments in remote storage until the topic lifetime. We
> > > decided to cleanup the segments with the oldest incase of size based
> > > retention also.
> > >
> > > 5102. RSM:
> > > 5102.1 For methods like fetchLogSegmentData(), it seems that they can
> > > use RemoteLogSegmentId instead of RemoteLogSegmentMetadata.
> > >
> > > It will be useful to have metadata for RSM to fetch log segment. It
> > > may create location/path using id with other metadata too.
> > >
> > > 5102.2 In fetchLogSegmentData(), should we use long instead of Long?
> > >
> > > Wanted to keep endPosition as optional to read till the end of the
> > > segment and avoid sentinels.
> > >
> > > 5102.3 Why only some of the methods have default implementation and
> > others
> > > Don't?
> > >
> > > Actually,  RSM will not have any default implementations. Those 3
> > > methods were made default earlier for tests etc. Updated the wiki.
> > >
> > > 5102.4. Could we define RemoteLogSegmentMetadataUpdate
> > > and DeletePartitionUpdate?
> > >
> > > Sure, they will be added.
> > >
> > >
> > > 5102.5 LogSegmentData: It seems that it's easier to pass
> > > in leaderEpochIndex as a ByteBuffer or byte array than a file since it
> > will
> > > be generated in memory.
> > >
> > > Right, this is in plan.
> > >
> > > 5102.6 RemoteLogSegmentMetadata: It seems that it needs both baseOffset
> > and
> > > startOffset. For example, deleteRecords() could move the startOffset to
> > the
> > > middle of a segment. If we copy the full segment to remote storage, the
> > > baseOffset and the startOffset will be different.
> > >
> > > Good point. startOffset is baseOffset by default, if not set explicitly.
> > >
> > > 5102.7 Could we define all the public methods for
> > RemoteLogSegmentMetadata
> > > and LogSegmentData?
> > >
> > > Sure, updated the wiki.
> > >
> > > 5102.8 Could we document whether endOffset in RemoteLogSegmentMetadata is
> > > inclusive/exclusive?
> > >
> > > It is inclusive, will update.
> > >
> > > 5103. configs:
> > > 5103.1 Could we define the default value of non-required configs (e.g the
> > > size of new thread pools)?
> > >
> > > Sure, that makes sense.
> > >
> > > 5103.2 It seems that local.log.retention.ms should default to
> > retention.ms,
> > > instead of remote.log.retention.minutes. Similarly, it seems
> > > that local.log.retention.bytes should default to segment.bytes.
> > >
> > > Right, we do not have  remote.log.retention as we discussed earlier.
> > > Thanks for catching the typo.
> > >
> > > 5103.3 remote.log.manager.thread.pool.size: The description says "used in
> > > scheduling tasks to copy segments, fetch remote log indexes and clean up
> > > remote log segments". However, there is a separate
> > > config remote.log.reader.threads for fetching remote data. It's weird to
> > > fetch remote index and log in different thread pools since both are used
> > > for serving fetch requests.
> > >
> > > Right, remote.log.manager.thread.pool is mainly used for copy/cleanup
> > > activities. Fetch path always goes through remote.log.reader.threads.
> > >
> > > 5103.4 remote.log.manager.task.interval.ms: Is that the amount of time
> > to
> > > back off when there is no work to do? If so, perhaps it can be renamed as
> > > backoff.ms.
> > >
> > > This is the delay interval for each iteration. It may be renamed to
> > > remote.log.manager.task.delay.ms
> > >
> > > 5103.5 Are rlm_process_interval_ms and rlm_retry_interval_ms configs? If
> > > so, they need to be listed in this section.
> > >
> > > remote.log.manager.task.interval.ms is the process internal, retry
> > > interval is missing in the configs, which will be updated in the KIP.
> > >
> > > 5104. "RLM maintains a bounded cache(possibly LRU) of the index files of
> > > remote log segments to avoid multiple index fetches from the remote
> > > storage." Is the RLM in memory or on disk? If on disk, where is it
> > stored?
> > > Do we need a configuration to bound the size?
> > >
> > > It is stored on disk. They are stored in a directory
> > > `remote-log-index-cache` under log dir. We plan to have a config for
> > > that instead of default. We will have a configuration for that.
> > >
> > > 5105. The KIP uses local-log-start-offset and Earliest Local Offset in
> > > different places. It would be useful to standardize the terminology.
> > >
> > > Sure.
> > >
> > > 5106. The section on "In BuildingRemoteLogAux state". It listed two
> > options
> > > without saying which option is chosen.
> > > We already mentioned in the KIP that we chose option-2.
> > >
> > > 5107. Follower to leader transition: It has step 2, but not step 1.
> > > Step-1 is there but it is not explicitly highlighted. It is previous
> > > table to step-2.
> > >
> > > 5108. If a consumer fetches from the remote data and the remote storage
> > is
> > > not available, what error code is used in the fetch response?
> > >
> > > Good point. We have not yet defined the error for this case. We need
> > > to define an error message and send the same in fetch response.
> > >
> > > 5109. "ListOffsets: For timestamps >= 0, it returns the first message
> > > offset whose timestamp is >= to the given timestamp in the request. That
> > > means it checks in remote log time indexes first, after which local log
> > > time indexes are checked." Could you document which method in RLMM is
> > used
> > > for this?
> > >
> > > Okay.
> > >
> > > 5110. Stopreplica: "it sets all the remote log segment metadata of that
> > > partition with a delete marker and publishes them to RLMM." This seems
> > > outdated given the new topic deletion logic.
> > >
> > > Will update with KIP-516 related points.
> > >
> > > 5111. "RLM follower fetches the earliest offset for the earliest leader
> > > epoch by calling RLMM.earliestLogOffset(TopicPartition topicPartition,
> > int
> > > leaderEpoch) and updates that as the log start offset." Do we need that
> > > since replication propagates logStartOffset already?
> > >
> > > Good point. Right, existing replication protocol takes care of
> > > updating the followers’s log start offset received from the leader.
> > >
> > > 5112. Is the default maxWaitMs of 500ms enough for fetching from remote
> > > storage?
> > >
> > > Remote reads may fail within the current default wait time, but
> > > subsequent fetches would be able to serve as that data is stored in
> > > the local cache. This cache is currently implemented in RSMs. But we
> > > plan to pull this into the remote log messaging layer in future.
> > >
> > > 5113. "Committed offsets can be stored in a local file to avoid reading
> > the
> > > messages again when a broker is restarted." Could you describe the format
> > > and the location of the file? Also, could the same message be processed
> > by
> > > RLMM again after broker restart? If so, how do we handle that?
> > >
> > > Sure, we will update in the KIP.
> > >
> > > 5114. Message format
> > > 5114.1 There are two records named RemoteLogSegmentMetadataRecord with
> > > apiKey 0 and 1.
> > >
> > > Nice catch, that was a typo. Fixed in the wiki.
> > >
> > > 5114.2 RemoteLogSegmentMetadataRecord: Could we document whether
> > endOffset
> > > is inclusive/exclusive?
> > > It is inclusive, will update.
> > >
> > > 5114.3 RemoteLogSegmentMetadataRecord: Could you explain LeaderEpoch a
> > bit
> > > more? Is that the epoch of the leader when it copies the segment to
> > remote
> > > storage? Also, how will this field be used?
> > >
> > > Right, this is the leader epoch of the broker which copied this
> > > segment. This is helpful in reason about which broker copied the
> > > segment to remote storage.
> > >
> > > 5114.4 EventTimestamp: Could you explain this a bit more? Each record in
> > > Kafka already has a timestamp field. Could we just use that?
> > >
> > > This is the  timestamp at which  the respective event occurred. Added
> > > this  to RemoteLogSegmentMetadata as RLMM can be  any other
> > > implementation. We thought about that but it looked cleaner to use at
> > > the message structure level instead of getting that from the consumer
> > > record and using that to build the respective event.
> > >
> > >
> > > 5114.5 SegmentSizeInBytes: Could this just be int32?
> > >
> > > Right, it looks like config allows only int value >= 14.
> > >
> > > 5115. RemoteLogCleaner(RLC): This could be confused with the log cleaner
> > > for compaction. Perhaps it can be renamed to sth like
> > > RemotePartitionRemover.
> > >
> > > I am fine with RemotePartitionRemover or RemoteLogDeletionManager(we
> > > have other manager classes like RLM, RLMM).
> > >
> > > 5116. "RLC receives the delete_partition_marked and processes it if it is
> > > not yet processed earlier." How does it know whether
> > > delete_partition_marked has been processed earlier?
> > >
> > > This is to handle duplicate delete_partition_marked events. RLC
> > > internally maintains a state for the delete_partition events and if it
> > > already has an existing event then it ignores if it is already being
> > > processed.
> > >
> > > 5117. Should we add a new MessageFormatter to read the tier metadata
> > topic?
> > >
> > > Right, this is in plan but did not mention it in the KIP. This will be
> > > useful for debugging purposes too.
> > >
> > > 5118. "Maximum remote log reader thread pool task queue size. If the task
> > > queue is full, broker will stop reading remote log segments." What do we
> > > return to the fetch request in this case?
> > >
> > > We return an error response for that partition.
> > >
> > > 5119. It would be useful to list all things not supported in the first
> > > version in a Future work or Limitations section. For example, compacted
> > > topic, JBOD, changing remote.log.storage.enable from true to false, etc.
> > >
> > > We already have a non-goals section which is filled with some of these
> > > details. Do we need another limitations section?
> > >
> > > Thanks,
> > > Satish.
> > >
> > > On Wed, Nov 4, 2020 at 11:27 PM Jun Rao <ju...@confluent.io> wrote:
> > > >
> > > > Hi, Satish,
> > > >
> > > > Thanks for the updated KIP. A few more comments below.
> > > >
> > > > 605.2 "Build the local leader epoch cache by cutting the leader epoch
> > > > sequence received from remote storage to [LSO, ELO]." I mentioned an
> > issue
> > > > earlier. Suppose the leader's local start offset is 100. The follower
> > finds
> > > > a remote segment covering offset range [80, 120). The producerState
> > with
> > > > this remote segment is up to offset 120. To trim the producerState to
> > > > offset 100 requires more work since one needs to download the previous
> > > > producerState up to offset 80 and then replay the messages from 80 to
> > 100.
> > > > It seems that it's simpler in this case for the follower just to take
> > the
> > > > remote segment as it is and start fetching from offset 120.
> > > >
> > > > 5016. Just to echo what Kowshik was saying. It seems that
> > > > RLMM.onPartitionLeadershipChanges() is only called on the replicas for
> > a
> > > > partition, not on the replicas for the __remote_log_segment_metadata
> > > > partition. It's not clear how the leader of
> > __remote_log_segment_metadata
> > > > obtains the metadata for remote segments for deletion.
> > > >
> > > > 5100. KIP-516 has been accepted and is being implemented now. Could you
> > > > update the KIP based on topicID?
> > > >
> > > > 5101. RLMM: It would be useful to clarify how the following two APIs
> > are
> > > > used. According to the wiki, the former is used for topic deletion and
> > the
> > > > latter is used for retention. It seems that retention should use the
> > former
> > > > since remote segments without a matching epoch in the leader
> > (potentially
> > > > due to unclean leader election) also need to be garbage collected. The
> > > > latter seems to be used for the new leader to determine the last tiered
> > > > segment.
> > > >     default Iterator<RemoteLogSegmentMetadata>
> > > > listRemoteLogSegments(TopicPartition topicPartition)
> > > >     Iterator<RemoteLogSegmentMetadata>
> > listRemoteLogSegments(TopicPartition
> > > > topicPartition, long leaderEpoch);
> > > >
> > > > 5102. RSM:
> > > > 5102.1 For methods like fetchLogSegmentData(), it seems that they can
> > > > use RemoteLogSegmentId instead of RemoteLogSegmentMetadata.
> > > > 5102.2 In fetchLogSegmentData(), should we use long instead of Long?
> > > > 5102.3 Why only some of the methods have default implementation and
> > others
> > > > don't?
> > > > 5102.4. Could we define RemoteLogSegmentMetadataUpdate
> > > > and DeletePartitionUpdate?
> > > > 5102.5 LogSegmentData: It seems that it's easier to pass
> > > > in leaderEpochIndex as a ByteBuffer or byte array than a file since it
> > will
> > > > be generated in memory.
> > > > 5102.6 RemoteLogSegmentMetadata: It seems that it needs both
> > baseOffset and
> > > > startOffset. For example, deleteRecords() could move the startOffset
> > to the
> > > > middle of a segment. If we copy the full segment to remote storage, the
> > > > baseOffset and the startOffset will be different.
> > > > 5102.7 Could we define all the public methods for
> > RemoteLogSegmentMetadata
> > > > and LogSegmentData?
> > > > 5102.8 Could we document whether endOffset in RemoteLogSegmentMetadata
> > is
> > > > inclusive/exclusive?
> > > >
> > > > 5103. configs:
> > > > 5103.1 Could we define the default value of non-required configs (e.g
> > the
> > > > size of new thread pools)?
> > > > 5103.2 It seems that local.log.retention.ms should default to
> > retention.ms,
> > > > instead of remote.log.retention.minutes. Similarly, it seems
> > > > that local.log.retention.bytes should default to segment.bytes.
> > > > 5103.3 remote.log.manager.thread.pool.size: The description says "used
> > in
> > > > scheduling tasks to copy segments, fetch remote log indexes and clean
> > up
> > > > remote log segments". However, there is a separate
> > > > config remote.log.reader.threads for fetching remote data. It's weird
> > to
> > > > fetch remote index and log in different thread pools since both are
> > used
> > > > for serving fetch requests.
> > > > 5103.4 remote.log.manager.task.interval.ms: Is that the amount of
> > time to
> > > > back off when there is no work to do? If so, perhaps it can be renamed
> > as
> > > > backoff.ms.
> > > > 5103.5 Are rlm_process_interval_ms and rlm_retry_interval_ms configs?
> > If
> > > > so, they need to be listed in this section.
> > > >
> > > > 5104. "RLM maintains a bounded cache(possibly LRU) of the index files
> > of
> > > > remote log segments to avoid multiple index fetches from the remote
> > > > storage." Is the RLM in memory or on disk? If on disk, where is it
> > stored?
> > > > Do we need a configuration to bound the size?
> > > >
> > > > 5105. The KIP uses local-log-start-offset and Earliest Local Offset in
> > > > different places. It would be useful to standardize the terminology.
> > > >
> > > > 5106. The section on "In BuildingRemoteLogAux state". It listed two
> > options
> > > > without saying which option is chosen.
> > > >
> > > > 5107. Follower to leader transition: It has step 2, but not step 1.
> > > >
> > > > 5108. If a consumer fetches from the remote data and the remote
> > storage is
> > > > not available, what error code is used in the fetch response?
> > > >
> > > > 5109. "ListOffsets: For timestamps >= 0, it returns the first message
> > > > offset whose timestamp is >= to the given timestamp in the request.
> > That
> > > > means it checks in remote log time indexes first, after which local log
> > > > time indexes are checked." Could you document which method in RLMM is
> > used
> > > > for this?
> > > >
> > > > 5110. Stopreplica: "it sets all the remote log segment metadata of that
> > > > partition with a delete marker and publishes them to RLMM." This seems
> > > > outdated given the new topic deletion logic.
> > > >
> > > > 5111. "RLM follower fetches the earliest offset for the earliest leader
> > > > epoch by calling RLMM.earliestLogOffset(TopicPartition topicPartition,
> > int
> > > > leaderEpoch) and updates that as the log start offset." Do we need that
> > > > since replication propagates logStartOffset already?
> > > >
> > > > 5112. Is the default maxWaitMs of 500ms enough for fetching from remote
> > > > storage?
> > > >
> > > > 5113. "Committed offsets can be stored in a local file to avoid
> > reading the
> > > > messages again when a broker is restarted." Could you describe the
> > format
> > > > and the location of the file? Also, could the same message be
> > processed by
> > > > RLMM again after broker restart? If so, how do we handle that?
> > > >
> > > > 5114. Message format
> > > > 5114.1 There are two records named RemoteLogSegmentMetadataRecord with
> > > > apiKey 0 and 1.
> > > > 5114.2 RemoteLogSegmentMetadataRecord: Could we document whether
> > endOffset
> > > > is inclusive/exclusive?
> > > > 5114.3 RemoteLogSegmentMetadataRecord: Could you explain LeaderEpoch a
> > bit
> > > > more? Is that the epoch of the leader when it copies the segment to
> > remote
> > > > storage? Also, how will this field be used?
> > > > 5114.4 EventTimestamp: Could you explain this a bit more? Each record
> > in
> > > > Kafka already has a timestamp field. Could we just use that?
> > > > 5114.5 SegmentSizeInBytes: Could this just be int32?
> > > >
> > > > 5115. RemoteLogCleaner(RLC): This could be confused with the log
> > cleaner
> > > > for compaction. Perhaps it can be renamed to sth like
> > > > RemotePartitionRemover.
> > > >
> > > > 5116. "RLC receives the delete_partition_marked and processes it if it
> > is
> > > > not yet processed earlier." How does it know whether
> > > > delete_partition_marked has been processed earlier?
> > > >
> > > > 5117. Should we add a new MessageFormatter to read the tier metadata
> > topic?
> > > >
> > > > 5118. "Maximum remote log reader thread pool task queue size. If the
> > task
> > > > queue is full, broker will stop reading remote log segments." What do
> > we
> > > > return to the fetch request in this case?
> > > >
> > > > 5119. It would be useful to list all things not supported in the first
> > > > version in a Future work or Limitations section. For example, compacted
> > > > topic, JBOD, changing remote.log.storage.enable from true to false,
> > etc.
> > > >
> > > > Thanks,
> > > >
> > > > Jun
> > > >
> > > > On Tue, Oct 27, 2020 at 5:57 PM Kowshik Prakasam <
> > kprakasam@confluent.io>
> > > > wrote:
> > > >
> > > > > Hi Satish,
> > > > >
> > > > > Thanks for the updates to the KIP. Here are my first batch of
> > > > > comments/suggestions on the latest version of the KIP.
> > > > >
> > > > > 5012. In the RemoteStorageManager interface, there is an API defined
> > for
> > > > > each file type. For example, fetchOffsetIndex, fetchTimestampIndex
> > etc. To
> > > > > avoid the duplication, I'd suggest we can instead have a FileType
> > enum and
> > > > > a common get API based on the FileType.
> > > > >
> > > > > 5013. There are some references to the Google doc in the KIP. I
> > wasn't sure
> > > > > if the Google doc is expected to be in sync with the contents of the
> > wiki.
> > > > > Going forward, it seems easier if just the KIP is maintained as the
> > source
> > > > > of truth. In this regard, could you please move all the references
> > to the
> > > > > Google doc, maybe to a separate References section at the bottom of
> > the
> > > > > KIP?
> > > > >
> > > > > 5014. There are some TODO sections in the KIP. Would these be filled
> > up in
> > > > > future iterations?
> > > > >
> > > > > 5015. Under "Topic deletion lifecycle", I'm trying to understand why
> > do we
> > > > > need delete_partition_marked as well as the delete_partition_started
> > > > > messages. I couldn't spot a drawback if supposing we simplified the
> > design
> > > > > such that the controller would only write delete_partition_started
> > message,
> > > > > and RemoteLogCleaner (RLC) instance picks it up for processing. What
> > am I
> > > > > missing?
> > > > >
> > > > > 5016. Under "Topic deletion lifecycle", step (4) is mentioned as
> > "RLC gets
> > > > > all the remote log segments for the partition and each of these
> > remote log
> > > > > segments is deleted with the next steps.". Since the RLC instance
> > runs on
> > > > > each tier topic partition leader, how does the RLC then get the list
> > of
> > > > > remote log segments to be deleted? It will be useful to add that
> > detail to
> > > > > the KIP.
> > > > >
> > > > > 5017. Under "Public Interfaces -> Configs", there is a line
> > mentioning "We
> > > > > will support flipping remote.log.storage.enable in next versions."
> > It will
> > > > > be useful to mention this in the "Future Work" section of the KIP
> > too.
> > > > >
> > > > > 5018. The KIP introduces a number of configuration parameters. It
> > will be
> > > > > useful to mention in the KIP if the user should assume these as
> > static
> > > > > configuration in the server.properties file, or dynamic
> > configuration which
> > > > > can be modified without restarting the broker.
> > > > >
> > > > > 5019.  Maybe this is planned as a future update to the KIP, but I
> > thought
> > > > > I'd mention it here. Could you please add details to the KIP on why
> > RocksDB
> > > > > was chosen as the default cache implementation of RLMM, and how it
> > is going
> > > > > to be used? Were alternatives compared/considered? For example, it
> > would be
> > > > > useful to explain/evaluate the following: 1) debuggability of the
> > RocksDB
> > > > > JNI interface, 2) performance, 3) portability across platforms and 4)
> > > > > interface parity of RocksDB’s JNI api with it's underlying C/C++ api.
> > > > >
> > > > > 5020. Following up on (5019), for the RocksDB cache, it will be
> > useful to
> > > > > explain the relationship/mapping between the following in the KIP:
> > 1) # of
> > > > > tiered partitions, 2) # of partitions of metadata topic
> > > > > __remote_log_metadata and 3) # of RocksDB instances. i.e. is the
> > plan to
> > > > > have a RocksDB instance per tiered partition, or per metadata topic
> > > > > partition, or just 1 for per broker?
> > > > >
> > > > > 5021. I was looking at the implementation prototype (PR link:
> > > > > https://github.com/apache/kafka/pull/7561). It seems that a boolean
> > > > > attribute is being introduced into the Log layer to check if remote
> > log
> > > > > capability is enabled. While the boolean footprint is small at the
> > moment,
> > > > > this can easily grow in the future and become harder to
> > > > > test/maintain, considering that the Log layer is already pretty
> > complex. We
> > > > > should start thinking about how to manage such changes to the Log
> > layer
> > > > > (for the purpose of improved testability, better separation of
> > concerns and
> > > > > readability). One proposal I have is to take a step back and define a
> > > > > higher level Log interface. Then, the Broker code can be changed to
> > use
> > > > > this interface. It can be changed such that only a handle to the
> > interface
> > > > > is exposed to other components (such as LogCleaner, ReplicaManager
> > etc.)
> > > > > and not the underlying Log object. This approach keeps the user of
> > the Log
> > > > > layer agnostic of the whereabouts of the data. Underneath the
> > interface,
> > > > > the implementing classes can completely separate local log
> > capabilities
> > > > > from the remote log. For example, the Log class can be simplified to
> > only
> > > > > manage logic surrounding local log segments and metadata.
> > Additionally, a
> > > > > wrapper class can be provided (implementing the higher level Log
> > interface)
> > > > > which will contain any/all logic surrounding tiered data. The wrapper
> > > > > class will wrap around an instance of the Log class delegating the
> > local
> > > > > log logic to it. Finally, a handle to the wrapper class can be
> > exposed to
> > > > > the other components wherever they need a handle to the higher level
> > Log
> > > > > interface.
> > > > >
> > > > >
> > > > > Cheers,
> > > > > Kowshik
> > > > >
> > > > > On Mon, Oct 26, 2020 at 9:52 PM Satish Duggana <
> > satish.duggana@gmail.com>
> > > > > wrote:
> > > > >
> > > > > > Hi,
> > > > > > KIP is updated with 1) topic deletion lifecycle and its related
> > items
> > > > > > 2) Protocol changes(mainly related to ListOffsets) and other minor
> > > > > > changes.
> > > > > > Please go through them and let us know your comments.
> > > > > >
> > > > > > Thanks,
> > > > > > Satish.
> > > > > >
> > > > > > On Mon, Sep 28, 2020 at 9:10 PM Satish Duggana <
> > satish.duggana@gmail.com
> > > > > >
> > > > > > wrote:
> > > > > > >
> > > > > > > Hi Dhruvil,
> > > > > > > Thanks for looking into the KIP and sending your comments. Sorry
> > for
> > > > > > > the late reply, missed it in the mail thread.
> > > > > > >
> > > > > > > 1. Could you describe how retention would work with this KIP and
> > which
> > > > > > > threads are responsible for driving this work? I believe there
> > are 3
> > > > > > kinds
> > > > > > > of retention processes we are looking at:
> > > > > > >   (a) Regular retention for data in tiered storage as per
> > configured `
> > > > > > > retention.ms` / `retention.bytes`.
> > > > > > >   (b) Local retention for data in local storage as per
> > configured `
> > > > > > > local.log.retention.ms` / `local.log.retention.bytes`
> > > > > > >   (c) Possibly regular retention for data in local storage, if
> > the
> > > > > > tiering
> > > > > > > task is lagging or for data that is below the log start offset.
> > > > > > >
> > > > > > > Local log retention is done by the existing log cleanup tasks.
> > These
> > > > > > > are not done for segments that are not yet copied to remote
> > storage.
> > > > > > > Remote log cleanup is done by the leader partition’s RLMTask.
> > > > > > >
> > > > > > > 2. When does a segment become eligible to be tiered? Is it as
> > soon as
> > > > > the
> > > > > > > segment is rolled and the end offset is less than the last stable
> > > > > offset
> > > > > > as
> > > > > > > mentioned in the KIP? I wonder if we need to consider other
> > parameters
> > > > > > too,
> > > > > > > like the highwatermark so that we are guaranteed that what we are
> > > > > tiering
> > > > > > > has been committed to the log and accepted by the ISR.
> > > > > > >
> > > > > > > AFAIK, last stable offset is always <= highwatermark. This will
> > make
> > > > > > > sure we are always tiering the message segments which have been
> > > > > > > accepted by ISR and transactionally completed.
> > > > > > >
> > > > > > >
> > > > > > > 3. The section on "Follower Fetch Scenarios" is useful but is a
> > bit
> > > > > > > difficult to parse at the moment. It would be useful to
> > summarize the
> > > > > > > changes we need in the ReplicaFetcher.
> > > > > > >
> > > > > > > It may become difficult for users to read/follow if we add code
> > changes
> > > > > > here.
> > > > > > >
> > > > > > > 4. Related to the above, it's a bit unclear how we are planning
> > on
> > > > > > > restoring the producer state for a new replica. Could you expand
> > on
> > > > > that?
> > > > > > >
> > > > > > > It is mentioned in the KIP BuildingRemoteLogAuxState is
> > introduced to
> > > > > > > build the state like leader epoch sequence and producer snapshots
> > > > > > > before it starts fetching the data from the leader. We will make
> > it
> > > > > > > clear in the KIP.
> > > > > > >
> > > > > > >
> > > > > > > 5. Similarly, it would be worth summarizing the behavior on
> > unclean
> > > > > > leader
> > > > > > > election. There are several scenarios to consider here: data
> > loss from
> > > > > > > local log, data loss from remote log, data loss from metadata
> > topic,
> > > > > etc.
> > > > > > > It's worth describing these in detail.
> > > > > > >
> > > > > > > We mentioned the cases about unclean leader election in the
> > follower
> > > > > > > fetch scenarios.
> > > > > > > If there are errors while fetching data from remote store or
> > metadata
> > > > > > > store, it will work the same way as it works with local log. It
> > > > > > > returns the error back to the caller. Please let us know if I am
> > > > > > > missing your point here.
> > > > > > >
> > > > > > >
> > > > > > > 7. For a READ_COMMITTED FetchRequest, how do we retrieve and
> > return the
> > > > > > > aborted transaction metadata?
> > > > > > >
> > > > > > > When a fetch for a remote log is accessed, we will fetch aborted
> > > > > > > transactions along with the segment if it is not found in the
> > local
> > > > > > > index cache. This includes the case of transaction index not
> > existing
> > > > > > > in the remote log segment. That means, the cache entry can be
> > empty or
> > > > > > > have a list of aborted transactions.
> > > > > > >
> > > > > > >
> > > > > > > 8. The `LogSegmentData` class assumes that we have a log segment,
> > > > > offset
> > > > > > > index, time index, transaction index, producer snapshot and
> > leader
> > > > > epoch
> > > > > > > index. How do we deal with cases where we do not have one or
> > more of
> > > > > > these?
> > > > > > > For example, we may not have a transaction index or producer
> > snapshot
> > > > > > for a
> > > > > > > particular segment. The former is optional, and the latter is
> > only kept
> > > > > > for
> > > > > > > up to the 3 latest segments.
> > > > > > >
> > > > > > > This is a good point,  we discussed this in the last meeting.
> > > > > > > Transaction index is optional and we will copy them only if it
> > exists.
> > > > > > > We want to keep all the producer snapshots at each log segment
> > rolling
> > > > > > > and they can be removed if the log copying is successful and it
> > still
> > > > > > > maintains the existing latest 3 segments, We only delete the
> > producer
> > > > > > > snapshots which have been copied to remote log segments on
> > leader.
> > > > > > > Follower will keep the log segments beyond the segments which
> > have not
> > > > > > > been copied to remote storage. We will update the KIP with these
> > > > > > > details.
> > > > > > >
> > > > > > > Thanks,
> > > > > > > Satish.
> > > > > > >
> > > > > > > On Thu, Sep 17, 2020 at 1:47 AM Dhruvil Shah <
> > dhruvil@confluent.io>
> > > > > > wrote:
> > > > > > > >
> > > > > > > > Hi Satish, Harsha,
> > > > > > > >
> > > > > > > > Thanks for the KIP. Few questions below:
> > > > > > > >
> > > > > > > > 1. Could you describe how retention would work with this KIP
> > and
> > > > > which
> > > > > > > > threads are responsible for driving this work? I believe there
> > are 3
> > > > > > kinds
> > > > > > > > of retention processes we are looking at:
> > > > > > > >   (a) Regular retention for data in tiered storage as per
> > configured
> > > > > `
> > > > > > > > retention.ms` / `retention.bytes`.
> > > > > > > >   (b) Local retention for data in local storage as per
> > configured `
> > > > > > > > local.log.retention.ms` / `local.log.retention.bytes`
> > > > > > > >   (c) Possibly regular retention for data in local storage, if
> > the
> > > > > > tiering
> > > > > > > > task is lagging or for data that is below the log start offset.
> > > > > > > >
> > > > > > > > 2. When does a segment become eligible to be tiered? Is it as
> > soon as
> > > > > > the
> > > > > > > > segment is rolled and the end offset is less than the last
> > stable
> > > > > > offset as
> > > > > > > > mentioned in the KIP? I wonder if we need to consider other
> > > > > parameters
> > > > > > too,
> > > > > > > > like the highwatermark so that we are guaranteed that what we
> > are
> > > > > > tiering
> > > > > > > > has been committed to the log and accepted by the ISR.
> > > > > > > >
> > > > > > > > 3. The section on "Follower Fetch Scenarios" is useful but is
> > a bit
> > > > > > > > difficult to parse at the moment. It would be useful to
> > summarize the
> > > > > > > > changes we need in the ReplicaFetcher.
> > > > > > > >
> > > > > > > > 4. Related to the above, it's a bit unclear how we are
> > planning on
> > > > > > > > restoring the producer state for a new replica. Could you
> > expand on
> > > > > > that?
> > > > > > > >
> > > > > > > > 5. Similarly, it would be worth summarizing the behavior on
> > unclean
> > > > > > leader
> > > > > > > > election. There are several scenarios to consider here: data
> > loss
> > > > > from
> > > > > > > > local log, data loss from remote log, data loss from metadata
> > topic,
> > > > > > etc.
> > > > > > > > It's worth describing these in detail.
> > > > > > > >
> > > > > > > > 6. It would be useful to add details about how we plan on using
> > > > > > RocksDB in
> > > > > > > > the default implementation of `RemoteLogMetadataManager`.
> > > > > > > >
> > > > > > > > 7. For a READ_COMMITTED FetchRequest, how do we retrieve and
> > return
> > > > > the
> > > > > > > > aborted transaction metadata?
> > > > > > > >
> > > > > > > > 8. The `LogSegmentData` class assumes that we have a log
> > segment,
> > > > > > offset
> > > > > > > > index, time index, transaction index, producer snapshot and
> > leader
> > > > > > epoch
> > > > > > > > index. How do we deal with cases where we do not have one or
> > more of
> > > > > > these?
> > > > > > > > For example, we may not have a transaction index or producer
> > snapshot
> > > > > > for a
> > > > > > > > particular segment. The former is optional, and the latter is
> > only
> > > > > > kept for
> > > > > > > > up to the 3 latest segments.
> > > > > > > >
> > > > > > > > Thanks,
> > > > > > > > Dhruvil
> > > > > > > >
> > > > > > > > On Mon, Sep 7, 2020 at 6:54 PM Harsha Ch <ha...@gmail.com>
> > > > > wrote:
> > > > > > > >
> > > > > > > > > Hi All,
> > > > > > > > >
> > > > > > > > > We are all working through the last meeting feedback. I'll
> > cancel
> > > > > the
> > > > > > > > > tomorrow 's meeting and we can meanwhile continue our
> > discussion in
> > > > > > mailing
> > > > > > > > > list. We can start the regular meeting from next week
> > onwards.
> > > > > > > > >
> > > > > > > > > Thanks,
> > > > > > > > >
> > > > > > > > > Harsha
> > > > > > > > >
> > > > > > > > > On Fri, Sep 04, 2020 at 8:41 AM, Satish Duggana <
> > > > > > satish.duggana@gmail.com
> > > > > > > > > > wrote:
> > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > Hi Jun,
> > > > > > > > > > Thanks for your thorough review and comments. Please find
> > the
> > > > > > inline
> > > > > > > > > > replies below.
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > 600. The topic deletion logic needs more details.
> > > > > > > > > > 600.1 The KIP mentions "The controller considers the topic
> > > > > > partition is
> > > > > > > > > > deleted only when it determines that there are no log
> > segments
> > > > > for
> > > > > > that
> > > > > > > > > > topic partition by using RLMM". How is this done?
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > It uses RLMM#listSegments() returns all the segments for
> > the
> > > > > given
> > > > > > topic
> > > > > > > > > > partition.
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > 600.2 "If the delete option is enabled then the leader
> > will stop
> > > > > > RLM task
> > > > > > > > > > and stop processing and it sets all the remote log segment
> > > > > > metadata of
> > > > > > > > > > that partition with a delete marker and publishes them to
> > RLMM."
> > > > > We
> > > > > > > > > > discussed this earlier. When a topic is being deleted,
> > there may
> > > > > > not be a
> > > > > > > > > > leader for the deleted partition.
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > This is a good point. As suggested in the meeting, we will
> > add a
> > > > > > separate
> > > > > > > > > > section for topic/partition deletion lifecycle and this
> > scenario
> > > > > > will be
> > > > > > > > > > addressed.
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > 601. Unclean leader election
> > > > > > > > > > 601.1 Scenario 1: new empty follower
> > > > > > > > > > After step 1, the follower restores up to offset 3. So why
> > does
> > > > > it
> > > > > > have
> > > > > > > > > > LE-2 <https://issues.apache.org/jira/browse/LE-2> at
> > offset 5?
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > Nice catch. It was showing the leader epoch fetched from
> > the
> > > > > remote
> > > > > > > > > > storage. It should be shown with the truncated till offset
> > 3.
> > > > > > Updated the
> > > > > > > > > > KIP.
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > 601.2 senario 5: After Step 3, leader A has inconsistent
> > data
> > > > > > between its
> > > > > > > > > > local and the tiered data. For example. offset 3 has msg 3
> > LE-0
> > > > > > <https://issues.apache.org/jira/browse/LE-0> locally,
> > > > > > > > > > but msg 5 LE-1 <https://issues.apache.org/jira/browse/LE-1>
> > in
> > > > > > the remote store. While it's ok for the unclean leader
> > > > > > > > > > to lose data, it should still return consistent data,
> > whether
> > > > > it's
> > > > > > from
> > > > > > > > > > the local or the remote store.
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > There is no inconsistency here as LE-0
> > > > > > <https://issues.apache.org/jira/browse/LE-0> offsets are [0, 4]
> > and LE-2
> > > > > > <https://issues.apache.org/jira/browse/LE-2>:
> > > > > > > > > > [5, ]. It will always get the right records for the given
> > offset
> > > > > > and
> > > > > > > > > > leader epoch. In case of remote, RSM is invoked to get the
> > remote
> > > > > > log
> > > > > > > > > > segment that contains the given offset with the leader
> > epoch.
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > 601.4 It seems that retention is based on
> > > > > > > > > > listRemoteLogSegments(TopicPartition topicPartition, long
> > > > > > leaderEpoch).
> > > > > > > > > > When there is an unclean leader election, it's possible
> > for the
> > > > > new
> > > > > > > > > leader
> > > > > > > > > > to not to include certain epochs in its epoch cache. How
> > are
> > > > > remote
> > > > > > > > > > segments associated with those epochs being cleaned?
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > That is a good point. This leader will also cleanup the
> > epochs
> > > > > > earlier to
> > > > > > > > > > its start leader epoch and delete those segments. It gets
> > the
> > > > > > earliest
> > > > > > > > > > epoch for a partition and starts deleting segments from
> > that
> > > > > leader
> > > > > > > > > epoch.
> > > > > > > > > > We need one more API in RLMM to get the earliest leader
> > epoch.
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > 601.5 The KIP discusses the handling of unclean leader
> > elections
> > > > > > for user
> > > > > > > > > > topics. What about unclean leader elections on
> > > > > > > > > > __remote_log_segment_metadata?
> > > > > > > > > > This is the same as other system topics like
> > consumer_offsets,
> > > > > > > > > > __transaction_state topics. As discussed in the meeting,
> > we will
> > > > > > add the
> > > > > > > > > > behavior of __remote_log_segment_metadata topic’s unclean
> > leader
> > > > > > > > > > truncation.
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > 602. It would be useful to clarify the limitations in the
> > initial
> > > > > > > > > release.
> > > > > > > > > > The KIP mentions not supporting compacted topics. What
> > about JBOD
> > > > > > and
> > > > > > > > > > changing the configuration of a topic from delete to
> > compact
> > > > > after
> > > > > > > > > remote.
> > > > > > > > > > log. storage. enable ( http://remote.log.storage.enable/
> > ) is
> > > > > > enabled?
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > This was updated in the KIP earlier.
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > 603. RLM leader tasks:
> > > > > > > > > > 603.1"It checks for rolled over LogSegments (which have
> > the last
> > > > > > message
> > > > > > > > > > offset less than last stable offset of that topic
> > partition) and
> > > > > > copies
> > > > > > > > > > them along with their offset/time/transaction indexes and
> > leader
> > > > > > epoch
> > > > > > > > > > cache to the remote tier." It needs to copy the producer
> > snapshot
> > > > > > too.
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > Right. It copies producer snapshots too as mentioned in
> > > > > > LogSegmentData.
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > 603.2 "Local logs are not cleaned up till those segments
> > are
> > > > > copied
> > > > > > > > > > successfully to remote even though their retention
> > time/size is
> > > > > > reached"
> > > > > > > > > > This seems weird. If the tiering stops because the remote
> > store
> > > > > is
> > > > > > not
> > > > > > > > > > available, we don't want the local data to grow forever.
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > It was clarified in the discussion that the comment was
> > more
> > > > > about
> > > > > > the
> > > > > > > > > > local storage goes beyond the log.retention. The above
> > statement
> > > > > > is about
> > > > > > > > > > local.log.retention but not for the complete
> > log.retention. When
> > > > > it
> > > > > > > > > > reaches the log.retention then it will delete the local
> > logs even
> > > > > > though
> > > > > > > > > > those are not copied to remote storage.
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > 604. "RLM maintains a bounded cache(possibly LRU) of the
> > index
> > > > > > files of
> > > > > > > > > > remote log segments to avoid multiple index fetches from
> > the
> > > > > remote
> > > > > > > > > > storage. These indexes can be used in the same way as local
> > > > > segment
> > > > > > > > > > indexes are used." Could you provide more details on this?
> > Are
> > > > > the
> > > > > > > > > indexes
> > > > > > > > > > cached in memory or on disk? If on disk, where are they
> > stored?
> > > > > > Are the
> > > > > > > > > > cached indexes bound by a certain size?
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > These are cached on disk and stored in log.dir with a name
> > > > > > > > > > “__remote_log_index_cache”. They are bound by the total
> > size.
> > > > > This
> > > > > > will
> > > > > > > > > be
> > > > > > > > > > exposed as a user configuration,
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > 605. BuildingRemoteLogAux
> > > > > > > > > > 605.1 In this section, two options are listed. Which one is
> > > > > chosen?
> > > > > > > > > > Option-2, updated the KIP.
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > 605.2 In option 2, it says "Build the local leader epoch
> > cache by
> > > > > > cutting
> > > > > > > > > > the leader epoch sequence received from remote storage to
> > [LSO,
> > > > > > ELO].
> > > > > > > > > (LSO
> > > > > > > > > >
> > > > > > > > > > = log start offset)." We need to do the same thing for the
> > > > > producer
> > > > > > > > > > snapshot. However, it's hard to cut the producer snapshot
> > to an
> > > > > > earlier
> > > > > > > > > > offset. Another option is to simply take the lastOffset
> > from the
> > > > > > remote
> > > > > > > > > > segment and use that as the starting fetch offset in the
> > > > > follower.
> > > > > > This
> > > > > > > > > > avoids the need for cutting.
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > Right, this was mentioned in the “transactional support”
> > section
> > > > > > about
> > > > > > > > > > adding these details.
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > 606. ListOffsets: Since we need a version bump, could you
> > > > > document
> > > > > > it
> > > > > > > > > > under a protocol change section?
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > Sure, we will update the KIP.
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > 607. "LogStartOffset of a topic can point to either of
> > local
> > > > > > segment or
> > > > > > > > > > remote segment but it is initialised and maintained in the
> > Log
> > > > > > class like
> > > > > > > > > > now. This is already maintained in `Log` class while
> > loading the
> > > > > > logs and
> > > > > > > > > > it can also be fetched from RemoteLogMetadataManager."
> > What will
> > > > > > happen
> > > > > > > > > to
> > > > > > > > > > the existing logic (e.g. log recovery) that currently
> > depends on
> > > > > > > > > > logStartOffset but assumes it's local?
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > They use a field called localLogStartOffset which is the
> > local
> > > > > log
> > > > > > start
> > > > > > > > > > offset..
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > 608. Handle expired remote segment: How does it pick up new
> > > > > > > > > logStartOffset
> > > > > > > > > > from deleteRecords?
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > Good point. This was not addressed in the KIP. Will update
> > the
> > > > > KIP
> > > > > > on how
> > > > > > > > > > the RLM task handles this scenario.
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > 609. RLMM message format:
> > > > > > > > > > 609.1 It includes both MaxTimestamp and EventTimestamp.
> > Where
> > > > > does
> > > > > > it get
> > > > > > > > > > both since the message in the log only contains one
> > timestamp?
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > `EventTimeStamp` is the timestamp at which that segment
> > metadata
> > > > > > event is
> > > > > > > > > > generated. This is more for audits.
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > 609.2 If we change just the state (e.g. to
> > DELETE_STARTED), it
> > > > > > seems it's
> > > > > > > > > > wasteful to have to include all other fields not changed.
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > This is a good point. We thought about incremental
> > updates. But
> > > > > we
> > > > > > want
> > > > > > > > > to
> > > > > > > > > > make sure all the events are in the expected order and take
> > > > > action
> > > > > > based
> > > > > > > > > > on the latest event. Will think through the approaches in
> > detail
> > > > > > and
> > > > > > > > > > update here.
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > 609.3 Could you document which process makes the following
> > > > > > transitions
> > > > > > > > > > DELETE_MARKED, DELETE_STARTED, DELETE_FINISHED?
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > Okay, will document more details.
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > 610. remote.log.reader.max.pending.tasks: "Maximum remote
> > log
> > > > > > reader
> > > > > > > > > > thread pool task queue size. If the task queue is full,
> > broker
> > > > > > will stop
> > > > > > > > > > reading remote log segments." What does the broker do if
> > the
> > > > > queue
> > > > > > is
> > > > > > > > > > full?
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > It returns an error for this topic partition.
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > 611. What do we return if the request offset/epoch doesn't
> > exist
> > > > > > in the
> > > > > > > > > > following API?
> > > > > > > > > > RemoteLogSegmentMetadata
> > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > > topicPartition, long offset, int epochForOffset)
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > This returns null. But we prefer to update the return type
> > as
> > > > > > Optional
> > > > > > > > > and
> > > > > > > > > > return Empty if that does not exist.
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > Thanks,
> > > > > > > > > > Satish.
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > On Tue, Sep 1, 2020 at 9:45 AM Jun Rao < jun@ confluent.
> > io (
> > > > > > > > > > jun@confluent.io ) > wrote:
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >>
> > > > > > > > > >>
> > > > > > > > > >> Hi, Satish,
> > > > > > > > > >>
> > > > > > > > > >>
> > > > > > > > > >>
> > > > > > > > > >> Thanks for the updated KIP. Made another pass. A few more
> > > > > comments
> > > > > > > > > below.
> > > > > > > > > >>
> > > > > > > > > >>
> > > > > > > > > >>
> > > > > > > > > >> 600. The topic deletion logic needs more details.
> > > > > > > > > >> 600.1 The KIP mentions "The controller considers the topic
> > > > > > partition is
> > > > > > > > > >> deleted only when it determines that there are no log
> > segments
> > > > > > for that
> > > > > > > > > >> topic partition by using RLMM". How is this done? 600.2
> > "If the
> > > > > > delete
> > > > > > > > > >> option is enabled then the leader will stop RLM task and
> > stop
> > > > > > processing
> > > > > > > > > >> and it sets all the remote log segment metadata of that
> > > > > partition
> > > > > > with a
> > > > > > > > > >> delete marker and publishes them to RLMM." We discussed
> > this
> > > > > > earlier.
> > > > > > > > > When
> > > > > > > > > >> a topic is being deleted, there may not be a leader for
> > the
> > > > > > deleted
> > > > > > > > > >> partition.
> > > > > > > > > >>
> > > > > > > > > >>
> > > > > > > > > >>
> > > > > > > > > >> 601. Unclean leader election
> > > > > > > > > >> 601.1 Scenario 1: new empty follower
> > > > > > > > > >> After step 1, the follower restores up to offset 3. So
> > why does
> > > > > > it have
> > > > > > > > > >> LE-2 <https://issues.apache.org/jira/browse/LE-2> at
> > offset 5?
> > > > > > > > > >> 601.2 senario 5: After Step 3, leader A has inconsistent
> > data
> > > > > > between
> > > > > > > > > its
> > > > > > > > > >> local and the tiered data. For example. offset 3 has msg
> > 3 LE-0
> > > > > > <https://issues.apache.org/jira/browse/LE-0> locally,
> > > > > > > > > >> but msg 5 LE-1 <
> > https://issues.apache.org/jira/browse/LE-1> in
> > > > > > the remote store. While it's ok for the unclean leader
> > > > > > > > > >> to lose data, it should still return consistent data,
> > whether
> > > > > > it's from
> > > > > > > > > >> the local or the remote store.
> > > > > > > > > >> 601.3 The follower picks up log start offset using the
> > following
> > > > > > api.
> > > > > > > > > >> Suppose that we have 3 remote segments (LE,
> > SegmentStartOffset)
> > > > > > as (2,
> > > > > > > > > >> 10),
> > > > > > > > > >> (3, 20) and (7, 15) due to an unclean leader election.
> > Using the
> > > > > > > > > following
> > > > > > > > > >> api will cause logStartOffset to go backward from 20 to
> > 15. How
> > > > > > do we
> > > > > > > > > >> prevent that?
> > > > > > > > > >> earliestLogOffset(TopicPartition topicPartition, int
> > > > > leaderEpoch)
> > > > > > 601.4
> > > > > > > > > It
> > > > > > > > > >> seems that retention is based on
> > > > > > > > > >> listRemoteLogSegments(TopicPartition topicPartition, long
> > > > > > leaderEpoch).
> > > > > > > > > >> When there is an unclean leader election, it's possible
> > for the
> > > > > > new
> > > > > > > > > leader
> > > > > > > > > >> to not to include certain epochs in its epoch cache. How
> > are
> > > > > > remote
> > > > > > > > > >> segments associated with those epochs being cleaned?
> > 601.5 The
> > > > > KIP
> > > > > > > > > >> discusses the handling of unclean leader elections for
> > user
> > > > > > topics. What
> > > > > > > > > >> about unclean leader elections on
> > > > > > > > > >> __remote_log_segment_metadata?
> > > > > > > > > >>
> > > > > > > > > >>
> > > > > > > > > >>
> > > > > > > > > >> 602. It would be useful to clarify the limitations in the
> > > > > initial
> > > > > > > > > release.
> > > > > > > > > >> The KIP mentions not supporting compacted topics. What
> > about
> > > > > JBOD
> > > > > > and
> > > > > > > > > >> changing the configuration of a topic from delete to
> > compact
> > > > > after
> > > > > > > > > remote.
> > > > > > > > > >> log. storage. enable ( http://remote.log.storage.enable/
> > ) is
> > > > > > enabled?
> > > > > > > > > >>
> > > > > > > > > >>
> > > > > > > > > >>
> > > > > > > > > >> 603. RLM leader tasks:
> > > > > > > > > >> 603.1"It checks for rolled over LogSegments (which have
> > the last
> > > > > > message
> > > > > > > > > >> offset less than last stable offset of that topic
> > partition) and
> > > > > > copies
> > > > > > > > > >> them along with their offset/time/transaction indexes and
> > leader
> > > > > > epoch
> > > > > > > > > >> cache to the remote tier." It needs to copy the producer
> > > > > snapshot
> > > > > > too.
> > > > > > > > > >> 603.2 "Local logs are not cleaned up till those segments
> > are
> > > > > > copied
> > > > > > > > > >> successfully to remote even though their retention
> > time/size is
> > > > > > reached"
> > > > > > > > > >> This seems weird. If the tiering stops because the remote
> > store
> > > > > > is not
> > > > > > > > > >> available, we don't want the local data to grow forever.
> > > > > > > > > >>
> > > > > > > > > >>
> > > > > > > > > >>
> > > > > > > > > >> 604. "RLM maintains a bounded cache(possibly LRU) of the
> > index
> > > > > > files of
> > > > > > > > > >> remote log segments to avoid multiple index fetches from
> > the
> > > > > > remote
> > > > > > > > > >> storage. These indexes can be used in the same way as
> > local
> > > > > > segment
> > > > > > > > > >> indexes are used." Could you provide more details on
> > this? Are
> > > > > the
> > > > > > > > > indexes
> > > > > > > > > >> cached in memory or on disk? If on disk, where are they
> > stored?
> > > > > > Are the
> > > > > > > > > >> cached indexes bound by a certain size?
> > > > > > > > > >>
> > > > > > > > > >>
> > > > > > > > > >>
> > > > > > > > > >> 605. BuildingRemoteLogAux
> > > > > > > > > >> 605.1 In this section, two options are listed. Which one
> > is
> > > > > > chosen?
> > > > > > > > > 605.2
> > > > > > > > > >> In option 2, it says "Build the local leader epoch cache
> > by
> > > > > > cutting the
> > > > > > > > > >> leader epoch sequence received from remote storage to
> > [LSO,
> > > > > ELO].
> > > > > > (LSO
> > > > > > > > > >> = log start offset)." We need to do the same thing for the
> > > > > > producer
> > > > > > > > > >> snapshot. However, it's hard to cut the producer snapshot
> > to an
> > > > > > earlier
> > > > > > > > > >> offset. Another option is to simply take the lastOffset
> > from the
> > > > > > remote
> > > > > > > > > >> segment and use that as the starting fetch offset in the
> > > > > > follower. This
> > > > > > > > > >> avoids the need for cutting.
> > > > > > > > > >>
> > > > > > > > > >>
> > > > > > > > > >>
> > > > > > > > > >> 606. ListOffsets: Since we need a version bump, could you
> > > > > > document it
> > > > > > > > > >> under a protocol change section?
> > > > > > > > > >>
> > > > > > > > > >>
> > > > > > > > > >>
> > > > > > > > > >> 607. "LogStartOffset of a topic can point to either of
> > local
> > > > > > segment or
> > > > > > > > > >> remote segment but it is initialised and maintained in
> > the Log
> > > > > > class
> > > > > > > > > like
> > > > > > > > > >> now. This is already maintained in `Log` class while
> > loading the
> > > > > > logs
> > > > > > > > > and
> > > > > > > > > >> it can also be fetched from RemoteLogMetadataManager."
> > What will
> > > > > > happen
> > > > > > > > > to
> > > > > > > > > >> the existing logic (e.g. log recovery) that currently
> > depends on
> > > > > > > > > >> logStartOffset but assumes it's local?
> > > > > > > > > >>
> > > > > > > > > >>
> > > > > > > > > >>
> > > > > > > > > >> 608. Handle expired remote segment: How does it pick up
> > new
> > > > > > > > > logStartOffset
> > > > > > > > > >> from deleteRecords?
> > > > > > > > > >>
> > > > > > > > > >>
> > > > > > > > > >>
> > > > > > > > > >> 609. RLMM message format:
> > > > > > > > > >> 609.1 It includes both MaxTimestamp and EventTimestamp.
> > Where
> > > > > > does it
> > > > > > > > > get
> > > > > > > > > >> both since the message in the log only contains one
> > timestamp?
> > > > > > 609.2 If
> > > > > > > > > we
> > > > > > > > > >> change just the state (e.g. to DELETE_STARTED), it seems
> > it's
> > > > > > wasteful
> > > > > > > > > to
> > > > > > > > > >> have to include all other fields not changed. 609.3 Could
> > you
> > > > > > document
> > > > > > > > > >> which process makes the following transitions
> > DELETE_MARKED,
> > > > > > > > > >> DELETE_STARTED, DELETE_FINISHED?
> > > > > > > > > >>
> > > > > > > > > >>
> > > > > > > > > >>
> > > > > > > > > >> 610. remote.log.reader.max.pending.tasks: "Maximum remote
> > log
> > > > > > reader
> > > > > > > > > >> thread pool task queue size. If the task queue is full,
> > broker
> > > > > > will stop
> > > > > > > > > >> reading remote log segments." What does the broker do if
> > the
> > > > > > queue is
> > > > > > > > > >> full?
> > > > > > > > > >>
> > > > > > > > > >>
> > > > > > > > > >>
> > > > > > > > > >> 611. What do we return if the request offset/epoch
> > doesn't exist
> > > > > > in the
> > > > > > > > > >> following API?
> > > > > > > > > >> RemoteLogSegmentMetadata
> > remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > >> topicPartition, long offset, int epochForOffset)
> > > > > > > > > >>
> > > > > > > > > >>
> > > > > > > > > >>
> > > > > > > > > >> Jun
> > > > > > > > > >>
> > > > > > > > > >>
> > > > > > > > > >>
> > > > > > > > > >> On Mon, Aug 31, 2020 at 11:19 AM Satish Duggana < satish.
> > > > > duggana@
> > > > > > > > > gmail. com
> > > > > > > > > >> ( satish.duggana@gmail.com ) > wrote:
> > > > > > > > > >>
> > > > > > > > > >>
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>> KIP is updated with
> > > > > > > > > >>> - Remote log segment metadata topic message
> > format/schema.
> > > > > > > > > >>> - Added remote log segment metadata state transitions and
> > > > > > explained how
> > > > > > > > > >>> the deletion of segments is handled, including the case
> > of
> > > > > > partition
> > > > > > > > > >>> deletions.
> > > > > > > > > >>> - Added a few more limitations in the "Non goals"
> > section.
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>> Thanks,
> > > > > > > > > >>> Satish.
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>> On Thu, Aug 27, 2020 at 12:42 AM Harsha Ch < harsha. ch@
> > > > > gmail.
> > > > > > com (
> > > > > > > > > >>> harsha.ch@gmail.com ) > wrote:
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>>>
> > > > > > > > > >>>>
> > > > > > > > > >>>> Updated the KIP with Meeting Notes section
> > > > > > > > > >>>>
> > > > > > > > > >>>>
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>> https:/ / cwiki. apache. org/ confluence/ display/ KAFKA/
> > > > > > > > > KIP-405 <https://issues.apache.org/jira/browse/KIP-405>
> > > > > > %3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> > > > > > > > > >>> (
> > > > > > > > > >>>
> > > > > > > > >
> > > > > >
> > > > >
> > https://cwiki.apache.org/confluence/display/KAFKA/KIP-405%3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> > > > > > > > > >>> )
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>>>
> > > > > > > > > >>>>
> > > > > > > > > >>>> On Tue, Aug 25, 2020 at 1:03 PM Jun Rao < jun@
> > confluent. io
> > > > > (
> > > > > > > > > >>>> jun@confluent.io ) > wrote:
> > > > > > > > > >>>>
> > > > > > > > > >>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>> Hi, Harsha,
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>> Thanks for the summary. Could you add the summary and
> > the
> > > > > > recording
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>
> > > > > > > > > >>>>
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>> link to
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>> the last section of
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>
> > > > > > > > > >>>>
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>> https:/ / cwiki. apache. org/ confluence/ display/ KAFKA/
> > > > > > > > > Kafka+Improvement+Proposals
> > > > > > > > > >>> (
> > > > > > > > > >>>
> > > > > > > > >
> > > > > >
> > > > >
> > https://cwiki.apache.org/confluence/display/KAFKA/Kafka+Improvement+Proposals
> > > > > > > > > >>> )
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>> ?
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>> Jun
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>> On Tue, Aug 25, 2020 at 11:12 AM Harsha Chintalapani <
> > kafka@
> > > > > > > > > harsha. io (
> > > > > > > > > >>>>> kafka@harsha.io ) > wrote:
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>> Thanks everyone for attending the meeting today.
> > > > > > > > > >>>>>> Here is the recording
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>
> > > > > > > > > >>>>
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>> https:/ / drive. google. com/ file/ d/
> > > > > > > > > 14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/ view?usp=sharing
> > > > > > > > > >>> (
> > > > > > > > > >>>
> > > > > > > > >
> > > > > >
> > > > >
> > https://drive.google.com/file/d/14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/view?usp=sharing
> > > > > > > > > >>> )
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>> Notes:
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>> 1. KIP is updated with follower fetch protocol and
> > ready to
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>
> > > > > > > > > >>>>
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>> reviewed
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>> 2. Satish to capture schema of internal metadata
> > topic in
> > > > > the
> > > > > > KIP
> > > > > > > > > >>>>>> 3. We will update the KIP with details of different
> > cases
> > > > > > > > > >>>>>> 4. Test plan will be captured in a doc and will add
> > to the
> > > > > KIP
> > > > > > > > > >>>>>> 5. Add a section "Limitations" to capture the
> > capabilities
> > > > > > that
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>
> > > > > > > > > >>>>
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>> will
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>> be
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>> introduced with this KIP and what will not be covered
> > in
> > > > > this
> > > > > > KIP.
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>> Please add to it I missed anything. Will produce a
> > formal
> > > > > > meeting
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>
> > > > > > > > > >>>>
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>> notes
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>> from next meeting onwards.
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>> Thanks,
> > > > > > > > > >>>>>> Harsha
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>> On Mon, Aug 24, 2020 at 9:42 PM, Ying Zheng < yingz@
> > uber.
> > > > > > com.
> > > > > > > > > invalid (
> > > > > > > > > >>>>>> yingz@uber.com.invalid ) > wrote:
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> We did some basic feature tests at Uber. The test
> > cases and
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>
> > > > > > > > > >>>>
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>> results are
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> shared in this google doc:
> > > > > > > > > >>>>>>> https:/ / docs. google. com/ spreadsheets/ d/ (
> > > > > > > > > >>>>>>> https://docs.google.com/spreadsheets/d/ )
> > > > > > > > > >>>>>>>
> > > > > 1XhNJqjzwXvMCcAOhEH0sSXU6RTvyoSf93DHF-YMfGLk/edit?usp=sharing
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> The performance test results were already shared in
> > the KIP
> > > > > > last
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>
> > > > > > > > > >>>>
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>> month.
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> On Mon, Aug 24, 2020 at 11:10 AM Harsha Ch < harsha.
> > ch@
> > > > > > gmail.
> > > > > > > > > com (
> > > > > > > > > >>>>>>> harsha.ch@gmail.com ) >
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>> wrote:
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> "Understand commitments towards driving design &
> > > > > > implementation of
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>
> > > > > > > > > >>>>
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>> the
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>> KIP
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> further and how it aligns with participant interests
> > in
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>
> > > > > > > > > >>>>
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>> contributing to
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>> the
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> efforts (ex: in the context of Uber’s Q3/Q4
> > roadmap)." What
> > > > > > is that
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>> about?
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> On Mon, Aug 24, 2020 at 11:05 AM Kowshik Prakasam <
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>> kprakasam@ confluent. io ( kprakasam@confluent.io ) >
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> wrote:
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> Hi Harsha,
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> The following google doc contains a proposal for
> > temporary
> > > > > > agenda
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>
> > > > > > > > > >>>>
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>> for
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>> the
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> KIP-405 <
> > https://issues.apache.org/jira/browse/KIP-405> <
> > > > > > https:/ / issues. apache. org/ jira/ browse/ KIP-405
> > > > > > <https://issues.apache.org/jira/browse/KIP-405> (
> > > > > > > > > >>>>>>> https://issues.apache.org/jira/browse/KIP-405 ) >
> > sync
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>
> > > > > > > > > >>>>
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>> meeting
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> tomorrow:
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> https:/ / docs. google. com/ document/ d/ (
> > > > > > > > > >>>>>>> https://docs.google.com/document/d/ )
> > > > > > > > > >>>>>>> 1pqo8X5LU8TpwfC_iqSuVPezhfCfhGkbGN2TqiPA3LBU/edit
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> .
> > > > > > > > > >>>>>>> Please could you add it to the Google calendar
> > invite?
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> Thank you.
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> Cheers,
> > > > > > > > > >>>>>>> Kowshik
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> On Thu, Aug 20, 2020 at 10:58 AM Harsha Ch < harsha.
> > ch@
> > > > > > gmail.
> > > > > > > > > com (
> > > > > > > > > >>>>>>> harsha.ch@gmail.com ) >
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>> wrote:
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> Hi All,
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> Scheduled a meeting for Tuesday 9am - 10am. I can
> > record
> > > > > and
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>
> > > > > > > > > >>>>
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>> upload for
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> community to be able to follow the discussion.
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> Jun, please add the required folks on confluent side.
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> Thanks,
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> Harsha
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> On Thu, Aug 20, 2020 at 12:33 AM, Alexandre Dupriez <
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>> alexandre.dupriez@
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> gmail. com ( http://gmail.com/ ) > wrote:
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> Hi Jun,
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> Many thanks for your initiative.
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> If you like, I am happy to attend at the time you
> > > > > suggested.
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> Many thanks,
> > > > > > > > > >>>>>>> Alexandre
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> Le mer. 19 août 2020 à 22:00, Harsha Ch < harsha. ch@
> > > > > > gmail. com (
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>> harsha.
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> ch@ gmail. com ( ch@gmail.com ) ) > a écrit :
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> Hi Jun,
> > > > > > > > > >>>>>>> Thanks. This will help a lot. Tuesday will work for
> > us.
> > > > > > > > > >>>>>>> -Harsha
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> On Wed, Aug 19, 2020 at 1:24 PM Jun Rao < jun@
> > confluent.
> > > > > > io (
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>
> > > > > > > > > >>>>
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>> jun@
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> confluent. io ( http://confluent.io/ ) ) > wrote:
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> Hi, Satish, Ying, Harsha,
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> Do you think it would be useful to have a regular
> > virtual
> > > > > > meeting
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>
> > > > > > > > > >>>>
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>> to
> > > > > > > > > >>>
> > > > > > > > > >>>
> > > > > > > > > >>>>
> > > > > > > > > >>>>>
> > > > > > > > > >>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> discuss this KIP? The goal of the meeting will be
> > sharing
> > > > > > > > > >>>>>>> design/development progress and discussing any open
> > issues
> > > > > to
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> accelerate
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> this KIP. If so, will every Tuesday (from next week)
> > > > > 9am-10am
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> PT
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> work for you? I can help set up a Zoom meeting,
> > invite
> > > > > > everyone who
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> might
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> be interested, have it recorded and shared, etc.
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> Thanks,
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> Jun
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> On Tue, Aug 18, 2020 at 11:01 AM Satish Duggana <
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> satish. duggana@ gmail. com ( satish. duggana@
> > gmail. com
> > > > > (
> > > > > > > > > >>>>>>> satish.duggana@gmail.com ) ) >
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> wrote:
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> Hi Kowshik,
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> Thanks for looking into the KIP and sending your
> > comments.
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>>
> > > > > > > > > >>>>>>> 5001. Under the section "Follower fetch protocol in
> > > > > detail",
> > > > > > the
> > > > > > > > > >>>>>>> next-local-offset is the offset upto which the
> > segments are
> > > > > > copied
> > > > > > > > > >>>>>>>
> > > > > >
> >
> >

Re: [DISCUSS] KIP-405: Kafka Tiered Storage

[Jun Rao <ju...@confluent.io>]

Hi, Satish,

Thanks for the updated KIP. A few more comments below.

605.2 It's rare for the follower to need the remote data. So, the current
approach is fine too. Could you document the process of rebuilding the
producer state since we can't simply trim the producerState to an offset in
the middle of a segment.

5102.2 Would it be clearer to make startPosiont long and endPosition of
Optional<Long>?

5102.5 LogSegmentData still has leaderEpochIndex as File instead of
ByteBuffer.

5102.7 Could you define all public methods for LogSegmentData?

5103.5 Could you change the reference to rlm_process_interval_ms and
rlm_retry_interval_ms to the new config names? Also, the retry interval
config seems still missing. It would be useful to support exponential
backoff with the retry interval config.

5111. "RLM follower fetches the earliest offset for the earliest leader
epoch by calling RLMM.earliestLogOffset(TopicPartition topicPartition, int
leaderEpoch) and updates that as the log start offset." This text is still
there. Also, could we remove earliestLogOffset() from RLMM?

5115. There are still references to "remote log cleaners".

6000. Since we are returning new error codes, we need to bump up the
protocol version for Fetch request. Also, it will be useful to document all
new error codes and whether they are retriable or not.

6001. public Map<Long, Long> segmentLeaderEpochs(): Currently, leaderEpoch
is int32 instead of long.

6002. Is RemoteLogSegmentMetadata.markedForDeletion() needed given
RemoteLogSegmentMetadata.state()?

6003. RemoteLogSegmentMetadata remoteLogSegmentMetadata(TopicPartition
topicPartition, long offset, int epochForOffset): Should this return
Optional<RemoteLogSegmentMetadata>?

6004. DeletePartitionUpdate.epoch(): It would be useful to pick a more
indicative name so that people understand what epoch this is.

6005. RemoteLogState: It seems it's better to split it between
DeletePartitionUpdate and RemoteLogSegmentMetadataUpdate since the states
are never shared between the two use cases.

6006. RLMM.onPartitionLeadershipChanges(): This may be ok. However, is it
ture that other than the metadata topic, RLMM just needs to know whether
there is a replica assigned to this broker and doesn't need to know whether
the replica is the leader or the follower?

6007: "Handle expired remote segments (leader and follower)": Why is this
needed in both the leader and the follower?

6008.       "name": "SegmentSizeInBytes",
                "type": "int64",
The segment size can just be int32.

6009. For the record format in the log, it seems that we need to add record
type and record version before the serialized bytes. We can follow the
convention used in
https://cwiki.apache.org/confluence/display/KAFKA/KIP-631%3A+The+Quorum-based+Kafka+Controller#KIP631:TheQuorumbasedKafkaController-RecordFormats
.

6010. remote.log.manager.thread.pool.size: The default value is 10. This
might be too high when enabling the tiered feature for the first time.
Since there are lots of segments that need to be tiered initially, a large
number of threads could overwhelm the broker.

6011. "The number of milli seconds to keep the local log segment before it
gets deleted. If not set, the value in `log.retention.minutes` is used. If
set to -1, no time limit is applied." We should use log.retention.ms
instead of log.retention.minutes.

Jun

On Tue, Dec 1, 2020 at 2:42 AM Satish Duggana <sa...@gmail.com>
wrote:

> Hi,
> We updated the KIP with the points mentioned in the earlier mail
> except for KIP-516 related changes. You can go through them and let us
> know if you have any comments. We will update the KIP with the
> remaining todo items and KIP-516 related changes by end of this
> week(5th Dec).
>
> Thanks,
> Satish.
>
> On Tue, Nov 10, 2020 at 8:26 PM Satish Duggana <sa...@gmail.com>
> wrote:
> >
> > Hi Jun,
> > Thanks for your comments. Please find the inline replies below.
> >
> > 605.2 "Build the local leader epoch cache by cutting the leader epoch
> > sequence received from remote storage to [LSO, ELO]." I mentioned an
> issue
> > earlier. Suppose the leader's local start offset is 100. The follower
> finds
> > a remote segment covering offset range [80, 120). The producerState with
> > this remote segment is up to offset 120. To trim the producerState to
> > offset 100 requires more work since one needs to download the previous
> > producerState up to offset 80 and then replay the messages from 80 to
> 100.
> > It seems that it's simpler in this case for the follower just to take the
> > remote segment as it is and start fetching from offset 120.
> >
> > We chose that approach to avoid any edge cases here. It may be
> > possible that the remote log segment that is received may not have the
> > same leader epoch sequence from 100-120 as it contains on the
> > leader(this can happen due to unclean leader). It is safe to start
> > from what the leader returns here.Another way is to find the remote
> > log segment
> >
> > 5016. Just to echo what Kowshik was saying. It seems that
> > RLMM.onPartitionLeadershipChanges() is only called on the replicas for a
> > partition, not on the replicas for the __remote_log_segment_metadata
> > partition. It's not clear how the leader of __remote_log_segment_metadata
> > obtains the metadata for remote segments for deletion.
> >
> > RLMM will always receive the callback for the remote log metadata
> > topic partitions hosted on the local broker and these will be
> > subscribed. I will make this clear in the KIP.
> >
> > 5100. KIP-516 has been accepted and is being implemented now. Could you
> > update the KIP based on topicID?
> >
> > We mentioned KIP-516 and how it helps. We will update this KIP with
> > all the changes it brings with KIP-516.
> >
> > 5101. RLMM: It would be useful to clarify how the following two APIs are
> > used. According to the wiki, the former is used for topic deletion and
> the
> > latter is used for retention. It seems that retention should use the
> former
> > since remote segments without a matching epoch in the leader (potentially
> > due to unclean leader election) also need to be garbage collected. The
> > latter seems to be used for the new leader to determine the last tiered
> > segment.
> >     default Iterator<RemoteLogSegmentMetadata>
> > listRemoteLogSegments(TopicPartition topicPartition)
> >     Iterator<RemoteLogSegmentMetadata>
> listRemoteLogSegments(TopicPartition
> > topicPartition, long leaderEpoch);
> >
> > Right,.that is what we are currently doing. We will update the
> > javadocs and wiki with that. Earlier, we did not want to remove the
> > segments which are not matched with leader epochs from the ladder
> > partition as they may be used later by a replica which can become a
> > leader (unclean leader election) and refer those segments. But that
> > may leak these segments in remote storage until the topic lifetime. We
> > decided to cleanup the segments with the oldest incase of size based
> > retention also.
> >
> > 5102. RSM:
> > 5102.1 For methods like fetchLogSegmentData(), it seems that they can
> > use RemoteLogSegmentId instead of RemoteLogSegmentMetadata.
> >
> > It will be useful to have metadata for RSM to fetch log segment. It
> > may create location/path using id with other metadata too.
> >
> > 5102.2 In fetchLogSegmentData(), should we use long instead of Long?
> >
> > Wanted to keep endPosition as optional to read till the end of the
> > segment and avoid sentinels.
> >
> > 5102.3 Why only some of the methods have default implementation and
> others
> > Don't?
> >
> > Actually,  RSM will not have any default implementations. Those 3
> > methods were made default earlier for tests etc. Updated the wiki.
> >
> > 5102.4. Could we define RemoteLogSegmentMetadataUpdate
> > and DeletePartitionUpdate?
> >
> > Sure, they will be added.
> >
> >
> > 5102.5 LogSegmentData: It seems that it's easier to pass
> > in leaderEpochIndex as a ByteBuffer or byte array than a file since it
> will
> > be generated in memory.
> >
> > Right, this is in plan.
> >
> > 5102.6 RemoteLogSegmentMetadata: It seems that it needs both baseOffset
> and
> > startOffset. For example, deleteRecords() could move the startOffset to
> the
> > middle of a segment. If we copy the full segment to remote storage, the
> > baseOffset and the startOffset will be different.
> >
> > Good point. startOffset is baseOffset by default, if not set explicitly.
> >
> > 5102.7 Could we define all the public methods for
> RemoteLogSegmentMetadata
> > and LogSegmentData?
> >
> > Sure, updated the wiki.
> >
> > 5102.8 Could we document whether endOffset in RemoteLogSegmentMetadata is
> > inclusive/exclusive?
> >
> > It is inclusive, will update.
> >
> > 5103. configs:
> > 5103.1 Could we define the default value of non-required configs (e.g the
> > size of new thread pools)?
> >
> > Sure, that makes sense.
> >
> > 5103.2 It seems that local.log.retention.ms should default to
> retention.ms,
> > instead of remote.log.retention.minutes. Similarly, it seems
> > that local.log.retention.bytes should default to segment.bytes.
> >
> > Right, we do not have  remote.log.retention as we discussed earlier.
> > Thanks for catching the typo.
> >
> > 5103.3 remote.log.manager.thread.pool.size: The description says "used in
> > scheduling tasks to copy segments, fetch remote log indexes and clean up
> > remote log segments". However, there is a separate
> > config remote.log.reader.threads for fetching remote data. It's weird to
> > fetch remote index and log in different thread pools since both are used
> > for serving fetch requests.
> >
> > Right, remote.log.manager.thread.pool is mainly used for copy/cleanup
> > activities. Fetch path always goes through remote.log.reader.threads.
> >
> > 5103.4 remote.log.manager.task.interval.ms: Is that the amount of time
> to
> > back off when there is no work to do? If so, perhaps it can be renamed as
> > backoff.ms.
> >
> > This is the delay interval for each iteration. It may be renamed to
> > remote.log.manager.task.delay.ms
> >
> > 5103.5 Are rlm_process_interval_ms and rlm_retry_interval_ms configs? If
> > so, they need to be listed in this section.
> >
> > remote.log.manager.task.interval.ms is the process internal, retry
> > interval is missing in the configs, which will be updated in the KIP.
> >
> > 5104. "RLM maintains a bounded cache(possibly LRU) of the index files of
> > remote log segments to avoid multiple index fetches from the remote
> > storage." Is the RLM in memory or on disk? If on disk, where is it
> stored?
> > Do we need a configuration to bound the size?
> >
> > It is stored on disk. They are stored in a directory
> > `remote-log-index-cache` under log dir. We plan to have a config for
> > that instead of default. We will have a configuration for that.
> >
> > 5105. The KIP uses local-log-start-offset and Earliest Local Offset in
> > different places. It would be useful to standardize the terminology.
> >
> > Sure.
> >
> > 5106. The section on "In BuildingRemoteLogAux state". It listed two
> options
> > without saying which option is chosen.
> > We already mentioned in the KIP that we chose option-2.
> >
> > 5107. Follower to leader transition: It has step 2, but not step 1.
> > Step-1 is there but it is not explicitly highlighted. It is previous
> > table to step-2.
> >
> > 5108. If a consumer fetches from the remote data and the remote storage
> is
> > not available, what error code is used in the fetch response?
> >
> > Good point. We have not yet defined the error for this case. We need
> > to define an error message and send the same in fetch response.
> >
> > 5109. "ListOffsets: For timestamps >= 0, it returns the first message
> > offset whose timestamp is >= to the given timestamp in the request. That
> > means it checks in remote log time indexes first, after which local log
> > time indexes are checked." Could you document which method in RLMM is
> used
> > for this?
> >
> > Okay.
> >
> > 5110. Stopreplica: "it sets all the remote log segment metadata of that
> > partition with a delete marker and publishes them to RLMM." This seems
> > outdated given the new topic deletion logic.
> >
> > Will update with KIP-516 related points.
> >
> > 5111. "RLM follower fetches the earliest offset for the earliest leader
> > epoch by calling RLMM.earliestLogOffset(TopicPartition topicPartition,
> int
> > leaderEpoch) and updates that as the log start offset." Do we need that
> > since replication propagates logStartOffset already?
> >
> > Good point. Right, existing replication protocol takes care of
> > updating the followers’s log start offset received from the leader.
> >
> > 5112. Is the default maxWaitMs of 500ms enough for fetching from remote
> > storage?
> >
> > Remote reads may fail within the current default wait time, but
> > subsequent fetches would be able to serve as that data is stored in
> > the local cache. This cache is currently implemented in RSMs. But we
> > plan to pull this into the remote log messaging layer in future.
> >
> > 5113. "Committed offsets can be stored in a local file to avoid reading
> the
> > messages again when a broker is restarted." Could you describe the format
> > and the location of the file? Also, could the same message be processed
> by
> > RLMM again after broker restart? If so, how do we handle that?
> >
> > Sure, we will update in the KIP.
> >
> > 5114. Message format
> > 5114.1 There are two records named RemoteLogSegmentMetadataRecord with
> > apiKey 0 and 1.
> >
> > Nice catch, that was a typo. Fixed in the wiki.
> >
> > 5114.2 RemoteLogSegmentMetadataRecord: Could we document whether
> endOffset
> > is inclusive/exclusive?
> > It is inclusive, will update.
> >
> > 5114.3 RemoteLogSegmentMetadataRecord: Could you explain LeaderEpoch a
> bit
> > more? Is that the epoch of the leader when it copies the segment to
> remote
> > storage? Also, how will this field be used?
> >
> > Right, this is the leader epoch of the broker which copied this
> > segment. This is helpful in reason about which broker copied the
> > segment to remote storage.
> >
> > 5114.4 EventTimestamp: Could you explain this a bit more? Each record in
> > Kafka already has a timestamp field. Could we just use that?
> >
> > This is the  timestamp at which  the respective event occurred. Added
> > this  to RemoteLogSegmentMetadata as RLMM can be  any other
> > implementation. We thought about that but it looked cleaner to use at
> > the message structure level instead of getting that from the consumer
> > record and using that to build the respective event.
> >
> >
> > 5114.5 SegmentSizeInBytes: Could this just be int32?
> >
> > Right, it looks like config allows only int value >= 14.
> >
> > 5115. RemoteLogCleaner(RLC): This could be confused with the log cleaner
> > for compaction. Perhaps it can be renamed to sth like
> > RemotePartitionRemover.
> >
> > I am fine with RemotePartitionRemover or RemoteLogDeletionManager(we
> > have other manager classes like RLM, RLMM).
> >
> > 5116. "RLC receives the delete_partition_marked and processes it if it is
> > not yet processed earlier." How does it know whether
> > delete_partition_marked has been processed earlier?
> >
> > This is to handle duplicate delete_partition_marked events. RLC
> > internally maintains a state for the delete_partition events and if it
> > already has an existing event then it ignores if it is already being
> > processed.
> >
> > 5117. Should we add a new MessageFormatter to read the tier metadata
> topic?
> >
> > Right, this is in plan but did not mention it in the KIP. This will be
> > useful for debugging purposes too.
> >
> > 5118. "Maximum remote log reader thread pool task queue size. If the task
> > queue is full, broker will stop reading remote log segments." What do we
> > return to the fetch request in this case?
> >
> > We return an error response for that partition.
> >
> > 5119. It would be useful to list all things not supported in the first
> > version in a Future work or Limitations section. For example, compacted
> > topic, JBOD, changing remote.log.storage.enable from true to false, etc.
> >
> > We already have a non-goals section which is filled with some of these
> > details. Do we need another limitations section?
> >
> > Thanks,
> > Satish.
> >
> > On Wed, Nov 4, 2020 at 11:27 PM Jun Rao <ju...@confluent.io> wrote:
> > >
> > > Hi, Satish,
> > >
> > > Thanks for the updated KIP. A few more comments below.
> > >
> > > 605.2 "Build the local leader epoch cache by cutting the leader epoch
> > > sequence received from remote storage to [LSO, ELO]." I mentioned an
> issue
> > > earlier. Suppose the leader's local start offset is 100. The follower
> finds
> > > a remote segment covering offset range [80, 120). The producerState
> with
> > > this remote segment is up to offset 120. To trim the producerState to
> > > offset 100 requires more work since one needs to download the previous
> > > producerState up to offset 80 and then replay the messages from 80 to
> 100.
> > > It seems that it's simpler in this case for the follower just to take
> the
> > > remote segment as it is and start fetching from offset 120.
> > >
> > > 5016. Just to echo what Kowshik was saying. It seems that
> > > RLMM.onPartitionLeadershipChanges() is only called on the replicas for
> a
> > > partition, not on the replicas for the __remote_log_segment_metadata
> > > partition. It's not clear how the leader of
> __remote_log_segment_metadata
> > > obtains the metadata for remote segments for deletion.
> > >
> > > 5100. KIP-516 has been accepted and is being implemented now. Could you
> > > update the KIP based on topicID?
> > >
> > > 5101. RLMM: It would be useful to clarify how the following two APIs
> are
> > > used. According to the wiki, the former is used for topic deletion and
> the
> > > latter is used for retention. It seems that retention should use the
> former
> > > since remote segments without a matching epoch in the leader
> (potentially
> > > due to unclean leader election) also need to be garbage collected. The
> > > latter seems to be used for the new leader to determine the last tiered
> > > segment.
> > >     default Iterator<RemoteLogSegmentMetadata>
> > > listRemoteLogSegments(TopicPartition topicPartition)
> > >     Iterator<RemoteLogSegmentMetadata>
> listRemoteLogSegments(TopicPartition
> > > topicPartition, long leaderEpoch);
> > >
> > > 5102. RSM:
> > > 5102.1 For methods like fetchLogSegmentData(), it seems that they can
> > > use RemoteLogSegmentId instead of RemoteLogSegmentMetadata.
> > > 5102.2 In fetchLogSegmentData(), should we use long instead of Long?
> > > 5102.3 Why only some of the methods have default implementation and
> others
> > > don't?
> > > 5102.4. Could we define RemoteLogSegmentMetadataUpdate
> > > and DeletePartitionUpdate?
> > > 5102.5 LogSegmentData: It seems that it's easier to pass
> > > in leaderEpochIndex as a ByteBuffer or byte array than a file since it
> will
> > > be generated in memory.
> > > 5102.6 RemoteLogSegmentMetadata: It seems that it needs both
> baseOffset and
> > > startOffset. For example, deleteRecords() could move the startOffset
> to the
> > > middle of a segment. If we copy the full segment to remote storage, the
> > > baseOffset and the startOffset will be different.
> > > 5102.7 Could we define all the public methods for
> RemoteLogSegmentMetadata
> > > and LogSegmentData?
> > > 5102.8 Could we document whether endOffset in RemoteLogSegmentMetadata
> is
> > > inclusive/exclusive?
> > >
> > > 5103. configs:
> > > 5103.1 Could we define the default value of non-required configs (e.g
> the
> > > size of new thread pools)?
> > > 5103.2 It seems that local.log.retention.ms should default to
> retention.ms,
> > > instead of remote.log.retention.minutes. Similarly, it seems
> > > that local.log.retention.bytes should default to segment.bytes.
> > > 5103.3 remote.log.manager.thread.pool.size: The description says "used
> in
> > > scheduling tasks to copy segments, fetch remote log indexes and clean
> up
> > > remote log segments". However, there is a separate
> > > config remote.log.reader.threads for fetching remote data. It's weird
> to
> > > fetch remote index and log in different thread pools since both are
> used
> > > for serving fetch requests.
> > > 5103.4 remote.log.manager.task.interval.ms: Is that the amount of
> time to
> > > back off when there is no work to do? If so, perhaps it can be renamed
> as
> > > backoff.ms.
> > > 5103.5 Are rlm_process_interval_ms and rlm_retry_interval_ms configs?
> If
> > > so, they need to be listed in this section.
> > >
> > > 5104. "RLM maintains a bounded cache(possibly LRU) of the index files
> of
> > > remote log segments to avoid multiple index fetches from the remote
> > > storage." Is the RLM in memory or on disk? If on disk, where is it
> stored?
> > > Do we need a configuration to bound the size?
> > >
> > > 5105. The KIP uses local-log-start-offset and Earliest Local Offset in
> > > different places. It would be useful to standardize the terminology.
> > >
> > > 5106. The section on "In BuildingRemoteLogAux state". It listed two
> options
> > > without saying which option is chosen.
> > >
> > > 5107. Follower to leader transition: It has step 2, but not step 1.
> > >
> > > 5108. If a consumer fetches from the remote data and the remote
> storage is
> > > not available, what error code is used in the fetch response?
> > >
> > > 5109. "ListOffsets: For timestamps >= 0, it returns the first message
> > > offset whose timestamp is >= to the given timestamp in the request.
> That
> > > means it checks in remote log time indexes first, after which local log
> > > time indexes are checked." Could you document which method in RLMM is
> used
> > > for this?
> > >
> > > 5110. Stopreplica: "it sets all the remote log segment metadata of that
> > > partition with a delete marker and publishes them to RLMM." This seems
> > > outdated given the new topic deletion logic.
> > >
> > > 5111. "RLM follower fetches the earliest offset for the earliest leader
> > > epoch by calling RLMM.earliestLogOffset(TopicPartition topicPartition,
> int
> > > leaderEpoch) and updates that as the log start offset." Do we need that
> > > since replication propagates logStartOffset already?
> > >
> > > 5112. Is the default maxWaitMs of 500ms enough for fetching from remote
> > > storage?
> > >
> > > 5113. "Committed offsets can be stored in a local file to avoid
> reading the
> > > messages again when a broker is restarted." Could you describe the
> format
> > > and the location of the file? Also, could the same message be
> processed by
> > > RLMM again after broker restart? If so, how do we handle that?
> > >
> > > 5114. Message format
> > > 5114.1 There are two records named RemoteLogSegmentMetadataRecord with
> > > apiKey 0 and 1.
> > > 5114.2 RemoteLogSegmentMetadataRecord: Could we document whether
> endOffset
> > > is inclusive/exclusive?
> > > 5114.3 RemoteLogSegmentMetadataRecord: Could you explain LeaderEpoch a
> bit
> > > more? Is that the epoch of the leader when it copies the segment to
> remote
> > > storage? Also, how will this field be used?
> > > 5114.4 EventTimestamp: Could you explain this a bit more? Each record
> in
> > > Kafka already has a timestamp field. Could we just use that?
> > > 5114.5 SegmentSizeInBytes: Could this just be int32?
> > >
> > > 5115. RemoteLogCleaner(RLC): This could be confused with the log
> cleaner
> > > for compaction. Perhaps it can be renamed to sth like
> > > RemotePartitionRemover.
> > >
> > > 5116. "RLC receives the delete_partition_marked and processes it if it
> is
> > > not yet processed earlier." How does it know whether
> > > delete_partition_marked has been processed earlier?
> > >
> > > 5117. Should we add a new MessageFormatter to read the tier metadata
> topic?
> > >
> > > 5118. "Maximum remote log reader thread pool task queue size. If the
> task
> > > queue is full, broker will stop reading remote log segments." What do
> we
> > > return to the fetch request in this case?
> > >
> > > 5119. It would be useful to list all things not supported in the first
> > > version in a Future work or Limitations section. For example, compacted
> > > topic, JBOD, changing remote.log.storage.enable from true to false,
> etc.
> > >
> > > Thanks,
> > >
> > > Jun
> > >
> > > On Tue, Oct 27, 2020 at 5:57 PM Kowshik Prakasam <
> kprakasam@confluent.io>
> > > wrote:
> > >
> > > > Hi Satish,
> > > >
> > > > Thanks for the updates to the KIP. Here are my first batch of
> > > > comments/suggestions on the latest version of the KIP.
> > > >
> > > > 5012. In the RemoteStorageManager interface, there is an API defined
> for
> > > > each file type. For example, fetchOffsetIndex, fetchTimestampIndex
> etc. To
> > > > avoid the duplication, I'd suggest we can instead have a FileType
> enum and
> > > > a common get API based on the FileType.
> > > >
> > > > 5013. There are some references to the Google doc in the KIP. I
> wasn't sure
> > > > if the Google doc is expected to be in sync with the contents of the
> wiki.
> > > > Going forward, it seems easier if just the KIP is maintained as the
> source
> > > > of truth. In this regard, could you please move all the references
> to the
> > > > Google doc, maybe to a separate References section at the bottom of
> the
> > > > KIP?
> > > >
> > > > 5014. There are some TODO sections in the KIP. Would these be filled
> up in
> > > > future iterations?
> > > >
> > > > 5015. Under "Topic deletion lifecycle", I'm trying to understand why
> do we
> > > > need delete_partition_marked as well as the delete_partition_started
> > > > messages. I couldn't spot a drawback if supposing we simplified the
> design
> > > > such that the controller would only write delete_partition_started
> message,
> > > > and RemoteLogCleaner (RLC) instance picks it up for processing. What
> am I
> > > > missing?
> > > >
> > > > 5016. Under "Topic deletion lifecycle", step (4) is mentioned as
> "RLC gets
> > > > all the remote log segments for the partition and each of these
> remote log
> > > > segments is deleted with the next steps.". Since the RLC instance
> runs on
> > > > each tier topic partition leader, how does the RLC then get the list
> of
> > > > remote log segments to be deleted? It will be useful to add that
> detail to
> > > > the KIP.
> > > >
> > > > 5017. Under "Public Interfaces -> Configs", there is a line
> mentioning "We
> > > > will support flipping remote.log.storage.enable in next versions."
> It will
> > > > be useful to mention this in the "Future Work" section of the KIP
> too.
> > > >
> > > > 5018. The KIP introduces a number of configuration parameters. It
> will be
> > > > useful to mention in the KIP if the user should assume these as
> static
> > > > configuration in the server.properties file, or dynamic
> configuration which
> > > > can be modified without restarting the broker.
> > > >
> > > > 5019.  Maybe this is planned as a future update to the KIP, but I
> thought
> > > > I'd mention it here. Could you please add details to the KIP on why
> RocksDB
> > > > was chosen as the default cache implementation of RLMM, and how it
> is going
> > > > to be used? Were alternatives compared/considered? For example, it
> would be
> > > > useful to explain/evaluate the following: 1) debuggability of the
> RocksDB
> > > > JNI interface, 2) performance, 3) portability across platforms and 4)
> > > > interface parity of RocksDB’s JNI api with it's underlying C/C++ api.
> > > >
> > > > 5020. Following up on (5019), for the RocksDB cache, it will be
> useful to
> > > > explain the relationship/mapping between the following in the KIP:
> 1) # of
> > > > tiered partitions, 2) # of partitions of metadata topic
> > > > __remote_log_metadata and 3) # of RocksDB instances. i.e. is the
> plan to
> > > > have a RocksDB instance per tiered partition, or per metadata topic
> > > > partition, or just 1 for per broker?
> > > >
> > > > 5021. I was looking at the implementation prototype (PR link:
> > > > https://github.com/apache/kafka/pull/7561). It seems that a boolean
> > > > attribute is being introduced into the Log layer to check if remote
> log
> > > > capability is enabled. While the boolean footprint is small at the
> moment,
> > > > this can easily grow in the future and become harder to
> > > > test/maintain, considering that the Log layer is already pretty
> complex. We
> > > > should start thinking about how to manage such changes to the Log
> layer
> > > > (for the purpose of improved testability, better separation of
> concerns and
> > > > readability). One proposal I have is to take a step back and define a
> > > > higher level Log interface. Then, the Broker code can be changed to
> use
> > > > this interface. It can be changed such that only a handle to the
> interface
> > > > is exposed to other components (such as LogCleaner, ReplicaManager
> etc.)
> > > > and not the underlying Log object. This approach keeps the user of
> the Log
> > > > layer agnostic of the whereabouts of the data. Underneath the
> interface,
> > > > the implementing classes can completely separate local log
> capabilities
> > > > from the remote log. For example, the Log class can be simplified to
> only
> > > > manage logic surrounding local log segments and metadata.
> Additionally, a
> > > > wrapper class can be provided (implementing the higher level Log
> interface)
> > > > which will contain any/all logic surrounding tiered data. The wrapper
> > > > class will wrap around an instance of the Log class delegating the
> local
> > > > log logic to it. Finally, a handle to the wrapper class can be
> exposed to
> > > > the other components wherever they need a handle to the higher level
> Log
> > > > interface.
> > > >
> > > >
> > > > Cheers,
> > > > Kowshik
> > > >
> > > > On Mon, Oct 26, 2020 at 9:52 PM Satish Duggana <
> satish.duggana@gmail.com>
> > > > wrote:
> > > >
> > > > > Hi,
> > > > > KIP is updated with 1) topic deletion lifecycle and its related
> items
> > > > > 2) Protocol changes(mainly related to ListOffsets) and other minor
> > > > > changes.
> > > > > Please go through them and let us know your comments.
> > > > >
> > > > > Thanks,
> > > > > Satish.
> > > > >
> > > > > On Mon, Sep 28, 2020 at 9:10 PM Satish Duggana <
> satish.duggana@gmail.com
> > > > >
> > > > > wrote:
> > > > > >
> > > > > > Hi Dhruvil,
> > > > > > Thanks for looking into the KIP and sending your comments. Sorry
> for
> > > > > > the late reply, missed it in the mail thread.
> > > > > >
> > > > > > 1. Could you describe how retention would work with this KIP and
> which
> > > > > > threads are responsible for driving this work? I believe there
> are 3
> > > > > kinds
> > > > > > of retention processes we are looking at:
> > > > > >   (a) Regular retention for data in tiered storage as per
> configured `
> > > > > > retention.ms` / `retention.bytes`.
> > > > > >   (b) Local retention for data in local storage as per
> configured `
> > > > > > local.log.retention.ms` / `local.log.retention.bytes`
> > > > > >   (c) Possibly regular retention for data in local storage, if
> the
> > > > > tiering
> > > > > > task is lagging or for data that is below the log start offset.
> > > > > >
> > > > > > Local log retention is done by the existing log cleanup tasks.
> These
> > > > > > are not done for segments that are not yet copied to remote
> storage.
> > > > > > Remote log cleanup is done by the leader partition’s RLMTask.
> > > > > >
> > > > > > 2. When does a segment become eligible to be tiered? Is it as
> soon as
> > > > the
> > > > > > segment is rolled and the end offset is less than the last stable
> > > > offset
> > > > > as
> > > > > > mentioned in the KIP? I wonder if we need to consider other
> parameters
> > > > > too,
> > > > > > like the highwatermark so that we are guaranteed that what we are
> > > > tiering
> > > > > > has been committed to the log and accepted by the ISR.
> > > > > >
> > > > > > AFAIK, last stable offset is always <= highwatermark. This will
> make
> > > > > > sure we are always tiering the message segments which have been
> > > > > > accepted by ISR and transactionally completed.
> > > > > >
> > > > > >
> > > > > > 3. The section on "Follower Fetch Scenarios" is useful but is a
> bit
> > > > > > difficult to parse at the moment. It would be useful to
> summarize the
> > > > > > changes we need in the ReplicaFetcher.
> > > > > >
> > > > > > It may become difficult for users to read/follow if we add code
> changes
> > > > > here.
> > > > > >
> > > > > > 4. Related to the above, it's a bit unclear how we are planning
> on
> > > > > > restoring the producer state for a new replica. Could you expand
> on
> > > > that?
> > > > > >
> > > > > > It is mentioned in the KIP BuildingRemoteLogAuxState is
> introduced to
> > > > > > build the state like leader epoch sequence and producer snapshots
> > > > > > before it starts fetching the data from the leader. We will make
> it
> > > > > > clear in the KIP.
> > > > > >
> > > > > >
> > > > > > 5. Similarly, it would be worth summarizing the behavior on
> unclean
> > > > > leader
> > > > > > election. There are several scenarios to consider here: data
> loss from
> > > > > > local log, data loss from remote log, data loss from metadata
> topic,
> > > > etc.
> > > > > > It's worth describing these in detail.
> > > > > >
> > > > > > We mentioned the cases about unclean leader election in the
> follower
> > > > > > fetch scenarios.
> > > > > > If there are errors while fetching data from remote store or
> metadata
> > > > > > store, it will work the same way as it works with local log. It
> > > > > > returns the error back to the caller. Please let us know if I am
> > > > > > missing your point here.
> > > > > >
> > > > > >
> > > > > > 7. For a READ_COMMITTED FetchRequest, how do we retrieve and
> return the
> > > > > > aborted transaction metadata?
> > > > > >
> > > > > > When a fetch for a remote log is accessed, we will fetch aborted
> > > > > > transactions along with the segment if it is not found in the
> local
> > > > > > index cache. This includes the case of transaction index not
> existing
> > > > > > in the remote log segment. That means, the cache entry can be
> empty or
> > > > > > have a list of aborted transactions.
> > > > > >
> > > > > >
> > > > > > 8. The `LogSegmentData` class assumes that we have a log segment,
> > > > offset
> > > > > > index, time index, transaction index, producer snapshot and
> leader
> > > > epoch
> > > > > > index. How do we deal with cases where we do not have one or
> more of
> > > > > these?
> > > > > > For example, we may not have a transaction index or producer
> snapshot
> > > > > for a
> > > > > > particular segment. The former is optional, and the latter is
> only kept
> > > > > for
> > > > > > up to the 3 latest segments.
> > > > > >
> > > > > > This is a good point,  we discussed this in the last meeting.
> > > > > > Transaction index is optional and we will copy them only if it
> exists.
> > > > > > We want to keep all the producer snapshots at each log segment
> rolling
> > > > > > and they can be removed if the log copying is successful and it
> still
> > > > > > maintains the existing latest 3 segments, We only delete the
> producer
> > > > > > snapshots which have been copied to remote log segments on
> leader.
> > > > > > Follower will keep the log segments beyond the segments which
> have not
> > > > > > been copied to remote storage. We will update the KIP with these
> > > > > > details.
> > > > > >
> > > > > > Thanks,
> > > > > > Satish.
> > > > > >
> > > > > > On Thu, Sep 17, 2020 at 1:47 AM Dhruvil Shah <
> dhruvil@confluent.io>
> > > > > wrote:
> > > > > > >
> > > > > > > Hi Satish, Harsha,
> > > > > > >
> > > > > > > Thanks for the KIP. Few questions below:
> > > > > > >
> > > > > > > 1. Could you describe how retention would work with this KIP
> and
> > > > which
> > > > > > > threads are responsible for driving this work? I believe there
> are 3
> > > > > kinds
> > > > > > > of retention processes we are looking at:
> > > > > > >   (a) Regular retention for data in tiered storage as per
> configured
> > > > `
> > > > > > > retention.ms` / `retention.bytes`.
> > > > > > >   (b) Local retention for data in local storage as per
> configured `
> > > > > > > local.log.retention.ms` / `local.log.retention.bytes`
> > > > > > >   (c) Possibly regular retention for data in local storage, if
> the
> > > > > tiering
> > > > > > > task is lagging or for data that is below the log start offset.
> > > > > > >
> > > > > > > 2. When does a segment become eligible to be tiered? Is it as
> soon as
> > > > > the
> > > > > > > segment is rolled and the end offset is less than the last
> stable
> > > > > offset as
> > > > > > > mentioned in the KIP? I wonder if we need to consider other
> > > > parameters
> > > > > too,
> > > > > > > like the highwatermark so that we are guaranteed that what we
> are
> > > > > tiering
> > > > > > > has been committed to the log and accepted by the ISR.
> > > > > > >
> > > > > > > 3. The section on "Follower Fetch Scenarios" is useful but is
> a bit
> > > > > > > difficult to parse at the moment. It would be useful to
> summarize the
> > > > > > > changes we need in the ReplicaFetcher.
> > > > > > >
> > > > > > > 4. Related to the above, it's a bit unclear how we are
> planning on
> > > > > > > restoring the producer state for a new replica. Could you
> expand on
> > > > > that?
> > > > > > >
> > > > > > > 5. Similarly, it would be worth summarizing the behavior on
> unclean
> > > > > leader
> > > > > > > election. There are several scenarios to consider here: data
> loss
> > > > from
> > > > > > > local log, data loss from remote log, data loss from metadata
> topic,
> > > > > etc.
> > > > > > > It's worth describing these in detail.
> > > > > > >
> > > > > > > 6. It would be useful to add details about how we plan on using
> > > > > RocksDB in
> > > > > > > the default implementation of `RemoteLogMetadataManager`.
> > > > > > >
> > > > > > > 7. For a READ_COMMITTED FetchRequest, how do we retrieve and
> return
> > > > the
> > > > > > > aborted transaction metadata?
> > > > > > >
> > > > > > > 8. The `LogSegmentData` class assumes that we have a log
> segment,
> > > > > offset
> > > > > > > index, time index, transaction index, producer snapshot and
> leader
> > > > > epoch
> > > > > > > index. How do we deal with cases where we do not have one or
> more of
> > > > > these?
> > > > > > > For example, we may not have a transaction index or producer
> snapshot
> > > > > for a
> > > > > > > particular segment. The former is optional, and the latter is
> only
> > > > > kept for
> > > > > > > up to the 3 latest segments.
> > > > > > >
> > > > > > > Thanks,
> > > > > > > Dhruvil
> > > > > > >
> > > > > > > On Mon, Sep 7, 2020 at 6:54 PM Harsha Ch <ha...@gmail.com>
> > > > wrote:
> > > > > > >
> > > > > > > > Hi All,
> > > > > > > >
> > > > > > > > We are all working through the last meeting feedback. I'll
> cancel
> > > > the
> > > > > > > > tomorrow 's meeting and we can meanwhile continue our
> discussion in
> > > > > mailing
> > > > > > > > list. We can start the regular meeting from next week
> onwards.
> > > > > > > >
> > > > > > > > Thanks,
> > > > > > > >
> > > > > > > > Harsha
> > > > > > > >
> > > > > > > > On Fri, Sep 04, 2020 at 8:41 AM, Satish Duggana <
> > > > > satish.duggana@gmail.com
> > > > > > > > > wrote:
> > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > Hi Jun,
> > > > > > > > > Thanks for your thorough review and comments. Please find
> the
> > > > > inline
> > > > > > > > > replies below.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > 600. The topic deletion logic needs more details.
> > > > > > > > > 600.1 The KIP mentions "The controller considers the topic
> > > > > partition is
> > > > > > > > > deleted only when it determines that there are no log
> segments
> > > > for
> > > > > that
> > > > > > > > > topic partition by using RLMM". How is this done?
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > It uses RLMM#listSegments() returns all the segments for
> the
> > > > given
> > > > > topic
> > > > > > > > > partition.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > 600.2 "If the delete option is enabled then the leader
> will stop
> > > > > RLM task
> > > > > > > > > and stop processing and it sets all the remote log segment
> > > > > metadata of
> > > > > > > > > that partition with a delete marker and publishes them to
> RLMM."
> > > > We
> > > > > > > > > discussed this earlier. When a topic is being deleted,
> there may
> > > > > not be a
> > > > > > > > > leader for the deleted partition.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > This is a good point. As suggested in the meeting, we will
> add a
> > > > > separate
> > > > > > > > > section for topic/partition deletion lifecycle and this
> scenario
> > > > > will be
> > > > > > > > > addressed.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > 601. Unclean leader election
> > > > > > > > > 601.1 Scenario 1: new empty follower
> > > > > > > > > After step 1, the follower restores up to offset 3. So why
> does
> > > > it
> > > > > have
> > > > > > > > > LE-2 <https://issues.apache.org/jira/browse/LE-2> at
> offset 5?
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > Nice catch. It was showing the leader epoch fetched from
> the
> > > > remote
> > > > > > > > > storage. It should be shown with the truncated till offset
> 3.
> > > > > Updated the
> > > > > > > > > KIP.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > 601.2 senario 5: After Step 3, leader A has inconsistent
> data
> > > > > between its
> > > > > > > > > local and the tiered data. For example. offset 3 has msg 3
> LE-0
> > > > > <https://issues.apache.org/jira/browse/LE-0> locally,
> > > > > > > > > but msg 5 LE-1 <https://issues.apache.org/jira/browse/LE-1>
> in
> > > > > the remote store. While it's ok for the unclean leader
> > > > > > > > > to lose data, it should still return consistent data,
> whether
> > > > it's
> > > > > from
> > > > > > > > > the local or the remote store.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > There is no inconsistency here as LE-0
> > > > > <https://issues.apache.org/jira/browse/LE-0> offsets are [0, 4]
> and LE-2
> > > > > <https://issues.apache.org/jira/browse/LE-2>:
> > > > > > > > > [5, ]. It will always get the right records for the given
> offset
> > > > > and
> > > > > > > > > leader epoch. In case of remote, RSM is invoked to get the
> remote
> > > > > log
> > > > > > > > > segment that contains the given offset with the leader
> epoch.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > 601.4 It seems that retention is based on
> > > > > > > > > listRemoteLogSegments(TopicPartition topicPartition, long
> > > > > leaderEpoch).
> > > > > > > > > When there is an unclean leader election, it's possible
> for the
> > > > new
> > > > > > > > leader
> > > > > > > > > to not to include certain epochs in its epoch cache. How
> are
> > > > remote
> > > > > > > > > segments associated with those epochs being cleaned?
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > That is a good point. This leader will also cleanup the
> epochs
> > > > > earlier to
> > > > > > > > > its start leader epoch and delete those segments. It gets
> the
> > > > > earliest
> > > > > > > > > epoch for a partition and starts deleting segments from
> that
> > > > leader
> > > > > > > > epoch.
> > > > > > > > > We need one more API in RLMM to get the earliest leader
> epoch.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > 601.5 The KIP discusses the handling of unclean leader
> elections
> > > > > for user
> > > > > > > > > topics. What about unclean leader elections on
> > > > > > > > > __remote_log_segment_metadata?
> > > > > > > > > This is the same as other system topics like
> consumer_offsets,
> > > > > > > > > __transaction_state topics. As discussed in the meeting,
> we will
> > > > > add the
> > > > > > > > > behavior of __remote_log_segment_metadata topic’s unclean
> leader
> > > > > > > > > truncation.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > 602. It would be useful to clarify the limitations in the
> initial
> > > > > > > > release.
> > > > > > > > > The KIP mentions not supporting compacted topics. What
> about JBOD
> > > > > and
> > > > > > > > > changing the configuration of a topic from delete to
> compact
> > > > after
> > > > > > > > remote.
> > > > > > > > > log. storage. enable ( http://remote.log.storage.enable/
> ) is
> > > > > enabled?
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > This was updated in the KIP earlier.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > 603. RLM leader tasks:
> > > > > > > > > 603.1"It checks for rolled over LogSegments (which have
> the last
> > > > > message
> > > > > > > > > offset less than last stable offset of that topic
> partition) and
> > > > > copies
> > > > > > > > > them along with their offset/time/transaction indexes and
> leader
> > > > > epoch
> > > > > > > > > cache to the remote tier." It needs to copy the producer
> snapshot
> > > > > too.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > Right. It copies producer snapshots too as mentioned in
> > > > > LogSegmentData.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > 603.2 "Local logs are not cleaned up till those segments
> are
> > > > copied
> > > > > > > > > successfully to remote even though their retention
> time/size is
> > > > > reached"
> > > > > > > > > This seems weird. If the tiering stops because the remote
> store
> > > > is
> > > > > not
> > > > > > > > > available, we don't want the local data to grow forever.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > It was clarified in the discussion that the comment was
> more
> > > > about
> > > > > the
> > > > > > > > > local storage goes beyond the log.retention. The above
> statement
> > > > > is about
> > > > > > > > > local.log.retention but not for the complete
> log.retention. When
> > > > it
> > > > > > > > > reaches the log.retention then it will delete the local
> logs even
> > > > > though
> > > > > > > > > those are not copied to remote storage.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > 604. "RLM maintains a bounded cache(possibly LRU) of the
> index
> > > > > files of
> > > > > > > > > remote log segments to avoid multiple index fetches from
> the
> > > > remote
> > > > > > > > > storage. These indexes can be used in the same way as local
> > > > segment
> > > > > > > > > indexes are used." Could you provide more details on this?
> Are
> > > > the
> > > > > > > > indexes
> > > > > > > > > cached in memory or on disk? If on disk, where are they
> stored?
> > > > > Are the
> > > > > > > > > cached indexes bound by a certain size?
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > These are cached on disk and stored in log.dir with a name
> > > > > > > > > “__remote_log_index_cache”. They are bound by the total
> size.
> > > > This
> > > > > will
> > > > > > > > be
> > > > > > > > > exposed as a user configuration,
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > 605. BuildingRemoteLogAux
> > > > > > > > > 605.1 In this section, two options are listed. Which one is
> > > > chosen?
> > > > > > > > > Option-2, updated the KIP.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > 605.2 In option 2, it says "Build the local leader epoch
> cache by
> > > > > cutting
> > > > > > > > > the leader epoch sequence received from remote storage to
> [LSO,
> > > > > ELO].
> > > > > > > > (LSO
> > > > > > > > >
> > > > > > > > > = log start offset)." We need to do the same thing for the
> > > > producer
> > > > > > > > > snapshot. However, it's hard to cut the producer snapshot
> to an
> > > > > earlier
> > > > > > > > > offset. Another option is to simply take the lastOffset
> from the
> > > > > remote
> > > > > > > > > segment and use that as the starting fetch offset in the
> > > > follower.
> > > > > This
> > > > > > > > > avoids the need for cutting.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > Right, this was mentioned in the “transactional support”
> section
> > > > > about
> > > > > > > > > adding these details.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > 606. ListOffsets: Since we need a version bump, could you
> > > > document
> > > > > it
> > > > > > > > > under a protocol change section?
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > Sure, we will update the KIP.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > 607. "LogStartOffset of a topic can point to either of
> local
> > > > > segment or
> > > > > > > > > remote segment but it is initialised and maintained in the
> Log
> > > > > class like
> > > > > > > > > now. This is already maintained in `Log` class while
> loading the
> > > > > logs and
> > > > > > > > > it can also be fetched from RemoteLogMetadataManager."
> What will
> > > > > happen
> > > > > > > > to
> > > > > > > > > the existing logic (e.g. log recovery) that currently
> depends on
> > > > > > > > > logStartOffset but assumes it's local?
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > They use a field called localLogStartOffset which is the
> local
> > > > log
> > > > > start
> > > > > > > > > offset..
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > 608. Handle expired remote segment: How does it pick up new
> > > > > > > > logStartOffset
> > > > > > > > > from deleteRecords?
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > Good point. This was not addressed in the KIP. Will update
> the
> > > > KIP
> > > > > on how
> > > > > > > > > the RLM task handles this scenario.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > 609. RLMM message format:
> > > > > > > > > 609.1 It includes both MaxTimestamp and EventTimestamp.
> Where
> > > > does
> > > > > it get
> > > > > > > > > both since the message in the log only contains one
> timestamp?
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > `EventTimeStamp` is the timestamp at which that segment
> metadata
> > > > > event is
> > > > > > > > > generated. This is more for audits.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > 609.2 If we change just the state (e.g. to
> DELETE_STARTED), it
> > > > > seems it's
> > > > > > > > > wasteful to have to include all other fields not changed.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > This is a good point. We thought about incremental
> updates. But
> > > > we
> > > > > want
> > > > > > > > to
> > > > > > > > > make sure all the events are in the expected order and take
> > > > action
> > > > > based
> > > > > > > > > on the latest event. Will think through the approaches in
> detail
> > > > > and
> > > > > > > > > update here.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > 609.3 Could you document which process makes the following
> > > > > transitions
> > > > > > > > > DELETE_MARKED, DELETE_STARTED, DELETE_FINISHED?
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > Okay, will document more details.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > 610. remote.log.reader.max.pending.tasks: "Maximum remote
> log
> > > > > reader
> > > > > > > > > thread pool task queue size. If the task queue is full,
> broker
> > > > > will stop
> > > > > > > > > reading remote log segments." What does the broker do if
> the
> > > > queue
> > > > > is
> > > > > > > > > full?
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > It returns an error for this topic partition.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > 611. What do we return if the request offset/epoch doesn't
> exist
> > > > > in the
> > > > > > > > > following API?
> > > > > > > > > RemoteLogSegmentMetadata
> remoteLogSegmentMetadata(TopicPartition
> > > > > > > > > topicPartition, long offset, int epochForOffset)
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > This returns null. But we prefer to update the return type
> as
> > > > > Optional
> > > > > > > > and
> > > > > > > > > return Empty if that does not exist.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > Thanks,
> > > > > > > > > Satish.
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > On Tue, Sep 1, 2020 at 9:45 AM Jun Rao < jun@ confluent.
> io (
> > > > > > > > > jun@confluent.io ) > wrote:
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >>
> > > > > > > > >>
> > > > > > > > >> Hi, Satish,
> > > > > > > > >>
> > > > > > > > >>
> > > > > > > > >>
> > > > > > > > >> Thanks for the updated KIP. Made another pass. A few more
> > > > comments
> > > > > > > > below.
> > > > > > > > >>
> > > > > > > > >>
> > > > > > > > >>
> > > > > > > > >> 600. The topic deletion logic needs more details.
> > > > > > > > >> 600.1 The KIP mentions "The controller considers the topic
> > > > > partition is
> > > > > > > > >> deleted only when it determines that there are no log
> segments
> > > > > for that
> > > > > > > > >> topic partition by using RLMM". How is this done? 600.2
> "If the
> > > > > delete
> > > > > > > > >> option is enabled then the leader will stop RLM task and
> stop
> > > > > processing
> > > > > > > > >> and it sets all the remote log segment metadata of that
> > > > partition
> > > > > with a
> > > > > > > > >> delete marker and publishes them to RLMM." We discussed
> this
> > > > > earlier.
> > > > > > > > When
> > > > > > > > >> a topic is being deleted, there may not be a leader for
> the
> > > > > deleted
> > > > > > > > >> partition.
> > > > > > > > >>
> > > > > > > > >>
> > > > > > > > >>
> > > > > > > > >> 601. Unclean leader election
> > > > > > > > >> 601.1 Scenario 1: new empty follower
> > > > > > > > >> After step 1, the follower restores up to offset 3. So
> why does
> > > > > it have
> > > > > > > > >> LE-2 <https://issues.apache.org/jira/browse/LE-2> at
> offset 5?
> > > > > > > > >> 601.2 senario 5: After Step 3, leader A has inconsistent
> data
> > > > > between
> > > > > > > > its
> > > > > > > > >> local and the tiered data. For example. offset 3 has msg
> 3 LE-0
> > > > > <https://issues.apache.org/jira/browse/LE-0> locally,
> > > > > > > > >> but msg 5 LE-1 <
> https://issues.apache.org/jira/browse/LE-1> in
> > > > > the remote store. While it's ok for the unclean leader
> > > > > > > > >> to lose data, it should still return consistent data,
> whether
> > > > > it's from
> > > > > > > > >> the local or the remote store.
> > > > > > > > >> 601.3 The follower picks up log start offset using the
> following
> > > > > api.
> > > > > > > > >> Suppose that we have 3 remote segments (LE,
> SegmentStartOffset)
> > > > > as (2,
> > > > > > > > >> 10),
> > > > > > > > >> (3, 20) and (7, 15) due to an unclean leader election.
> Using the
> > > > > > > > following
> > > > > > > > >> api will cause logStartOffset to go backward from 20 to
> 15. How
> > > > > do we
> > > > > > > > >> prevent that?
> > > > > > > > >> earliestLogOffset(TopicPartition topicPartition, int
> > > > leaderEpoch)
> > > > > 601.4
> > > > > > > > It
> > > > > > > > >> seems that retention is based on
> > > > > > > > >> listRemoteLogSegments(TopicPartition topicPartition, long
> > > > > leaderEpoch).
> > > > > > > > >> When there is an unclean leader election, it's possible
> for the
> > > > > new
> > > > > > > > leader
> > > > > > > > >> to not to include certain epochs in its epoch cache. How
> are
> > > > > remote
> > > > > > > > >> segments associated with those epochs being cleaned?
> 601.5 The
> > > > KIP
> > > > > > > > >> discusses the handling of unclean leader elections for
> user
> > > > > topics. What
> > > > > > > > >> about unclean leader elections on
> > > > > > > > >> __remote_log_segment_metadata?
> > > > > > > > >>
> > > > > > > > >>
> > > > > > > > >>
> > > > > > > > >> 602. It would be useful to clarify the limitations in the
> > > > initial
> > > > > > > > release.
> > > > > > > > >> The KIP mentions not supporting compacted topics. What
> about
> > > > JBOD
> > > > > and
> > > > > > > > >> changing the configuration of a topic from delete to
> compact
> > > > after
> > > > > > > > remote.
> > > > > > > > >> log. storage. enable ( http://remote.log.storage.enable/
> ) is
> > > > > enabled?
> > > > > > > > >>
> > > > > > > > >>
> > > > > > > > >>
> > > > > > > > >> 603. RLM leader tasks:
> > > > > > > > >> 603.1"It checks for rolled over LogSegments (which have
> the last
> > > > > message
> > > > > > > > >> offset less than last stable offset of that topic
> partition) and
> > > > > copies
> > > > > > > > >> them along with their offset/time/transaction indexes and
> leader
> > > > > epoch
> > > > > > > > >> cache to the remote tier." It needs to copy the producer
> > > > snapshot
> > > > > too.
> > > > > > > > >> 603.2 "Local logs are not cleaned up till those segments
> are
> > > > > copied
> > > > > > > > >> successfully to remote even though their retention
> time/size is
> > > > > reached"
> > > > > > > > >> This seems weird. If the tiering stops because the remote
> store
> > > > > is not
> > > > > > > > >> available, we don't want the local data to grow forever.
> > > > > > > > >>
> > > > > > > > >>
> > > > > > > > >>
> > > > > > > > >> 604. "RLM maintains a bounded cache(possibly LRU) of the
> index
> > > > > files of
> > > > > > > > >> remote log segments to avoid multiple index fetches from
> the
> > > > > remote
> > > > > > > > >> storage. These indexes can be used in the same way as
> local
> > > > > segment
> > > > > > > > >> indexes are used." Could you provide more details on
> this? Are
> > > > the
> > > > > > > > indexes
> > > > > > > > >> cached in memory or on disk? If on disk, where are they
> stored?
> > > > > Are the
> > > > > > > > >> cached indexes bound by a certain size?
> > > > > > > > >>
> > > > > > > > >>
> > > > > > > > >>
> > > > > > > > >> 605. BuildingRemoteLogAux
> > > > > > > > >> 605.1 In this section, two options are listed. Which one
> is
> > > > > chosen?
> > > > > > > > 605.2
> > > > > > > > >> In option 2, it says "Build the local leader epoch cache
> by
> > > > > cutting the
> > > > > > > > >> leader epoch sequence received from remote storage to
> [LSO,
> > > > ELO].
> > > > > (LSO
> > > > > > > > >> = log start offset)." We need to do the same thing for the
> > > > > producer
> > > > > > > > >> snapshot. However, it's hard to cut the producer snapshot
> to an
> > > > > earlier
> > > > > > > > >> offset. Another option is to simply take the lastOffset
> from the
> > > > > remote
> > > > > > > > >> segment and use that as the starting fetch offset in the
> > > > > follower. This
> > > > > > > > >> avoids the need for cutting.
> > > > > > > > >>
> > > > > > > > >>
> > > > > > > > >>
> > > > > > > > >> 606. ListOffsets: Since we need a version bump, could you
> > > > > document it
> > > > > > > > >> under a protocol change section?
> > > > > > > > >>
> > > > > > > > >>
> > > > > > > > >>
> > > > > > > > >> 607. "LogStartOffset of a topic can point to either of
> local
> > > > > segment or
> > > > > > > > >> remote segment but it is initialised and maintained in
> the Log
> > > > > class
> > > > > > > > like
> > > > > > > > >> now. This is already maintained in `Log` class while
> loading the
> > > > > logs
> > > > > > > > and
> > > > > > > > >> it can also be fetched from RemoteLogMetadataManager."
> What will
> > > > > happen
> > > > > > > > to
> > > > > > > > >> the existing logic (e.g. log recovery) that currently
> depends on
> > > > > > > > >> logStartOffset but assumes it's local?
> > > > > > > > >>
> > > > > > > > >>
> > > > > > > > >>
> > > > > > > > >> 608. Handle expired remote segment: How does it pick up
> new
> > > > > > > > logStartOffset
> > > > > > > > >> from deleteRecords?
> > > > > > > > >>
> > > > > > > > >>
> > > > > > > > >>
> > > > > > > > >> 609. RLMM message format:
> > > > > > > > >> 609.1 It includes both MaxTimestamp and EventTimestamp.
> Where
> > > > > does it
> > > > > > > > get
> > > > > > > > >> both since the message in the log only contains one
> timestamp?
> > > > > 609.2 If
> > > > > > > > we
> > > > > > > > >> change just the state (e.g. to DELETE_STARTED), it seems
> it's
> > > > > wasteful
> > > > > > > > to
> > > > > > > > >> have to include all other fields not changed. 609.3 Could
> you
> > > > > document
> > > > > > > > >> which process makes the following transitions
> DELETE_MARKED,
> > > > > > > > >> DELETE_STARTED, DELETE_FINISHED?
> > > > > > > > >>
> > > > > > > > >>
> > > > > > > > >>
> > > > > > > > >> 610. remote.log.reader.max.pending.tasks: "Maximum remote
> log
> > > > > reader
> > > > > > > > >> thread pool task queue size. If the task queue is full,
> broker
> > > > > will stop
> > > > > > > > >> reading remote log segments." What does the broker do if
> the
> > > > > queue is
> > > > > > > > >> full?
> > > > > > > > >>
> > > > > > > > >>
> > > > > > > > >>
> > > > > > > > >> 611. What do we return if the request offset/epoch
> doesn't exist
> > > > > in the
> > > > > > > > >> following API?
> > > > > > > > >> RemoteLogSegmentMetadata
> remoteLogSegmentMetadata(TopicPartition
> > > > > > > > >> topicPartition, long offset, int epochForOffset)
> > > > > > > > >>
> > > > > > > > >>
> > > > > > > > >>
> > > > > > > > >> Jun
> > > > > > > > >>
> > > > > > > > >>
> > > > > > > > >>
> > > > > > > > >> On Mon, Aug 31, 2020 at 11:19 AM Satish Duggana < satish.
> > > > duggana@
> > > > > > > > gmail. com
> > > > > > > > >> ( satish.duggana@gmail.com ) > wrote:
> > > > > > > > >>
> > > > > > > > >>
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>> KIP is updated with
> > > > > > > > >>> - Remote log segment metadata topic message
> format/schema.
> > > > > > > > >>> - Added remote log segment metadata state transitions and
> > > > > explained how
> > > > > > > > >>> the deletion of segments is handled, including the case
> of
> > > > > partition
> > > > > > > > >>> deletions.
> > > > > > > > >>> - Added a few more limitations in the "Non goals"
> section.
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>> Thanks,
> > > > > > > > >>> Satish.
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>> On Thu, Aug 27, 2020 at 12:42 AM Harsha Ch < harsha. ch@
> > > > gmail.
> > > > > com (
> > > > > > > > >>> harsha.ch@gmail.com ) > wrote:
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>>>
> > > > > > > > >>>>
> > > > > > > > >>>> Updated the KIP with Meeting Notes section
> > > > > > > > >>>>
> > > > > > > > >>>>
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>> https:/ / cwiki. apache. org/ confluence/ display/ KAFKA/
> > > > > > > > KIP-405 <https://issues.apache.org/jira/browse/KIP-405>
> > > > > %3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> > > > > > > > >>> (
> > > > > > > > >>>
> > > > > > > >
> > > > >
> > > >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-405%3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> > > > > > > > >>> )
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>>>
> > > > > > > > >>>>
> > > > > > > > >>>> On Tue, Aug 25, 2020 at 1:03 PM Jun Rao < jun@
> confluent. io
> > > > (
> > > > > > > > >>>> jun@confluent.io ) > wrote:
> > > > > > > > >>>>
> > > > > > > > >>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>> Hi, Harsha,
> > > > > > > > >>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>> Thanks for the summary. Could you add the summary and
> the
> > > > > recording
> > > > > > > > >>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>
> > > > > > > > >>>>
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>> link to
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>> the last section of
> > > > > > > > >>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>
> > > > > > > > >>>>
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>> https:/ / cwiki. apache. org/ confluence/ display/ KAFKA/
> > > > > > > > Kafka+Improvement+Proposals
> > > > > > > > >>> (
> > > > > > > > >>>
> > > > > > > >
> > > > >
> > > >
> https://cwiki.apache.org/confluence/display/KAFKA/Kafka+Improvement+Proposals
> > > > > > > > >>> )
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>> ?
> > > > > > > > >>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>> Jun
> > > > > > > > >>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>> On Tue, Aug 25, 2020 at 11:12 AM Harsha Chintalapani <
> kafka@
> > > > > > > > harsha. io (
> > > > > > > > >>>>> kafka@harsha.io ) > wrote:
> > > > > > > > >>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>> Thanks everyone for attending the meeting today.
> > > > > > > > >>>>>> Here is the recording
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>
> > > > > > > > >>>>
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>> https:/ / drive. google. com/ file/ d/
> > > > > > > > 14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/ view?usp=sharing
> > > > > > > > >>> (
> > > > > > > > >>>
> > > > > > > >
> > > > >
> > > >
> https://drive.google.com/file/d/14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/view?usp=sharing
> > > > > > > > >>> )
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>> Notes:
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>> 1. KIP is updated with follower fetch protocol and
> ready to
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>
> > > > > > > > >>>>
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>> reviewed
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>> 2. Satish to capture schema of internal metadata
> topic in
> > > > the
> > > > > KIP
> > > > > > > > >>>>>> 3. We will update the KIP with details of different
> cases
> > > > > > > > >>>>>> 4. Test plan will be captured in a doc and will add
> to the
> > > > KIP
> > > > > > > > >>>>>> 5. Add a section "Limitations" to capture the
> capabilities
> > > > > that
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>
> > > > > > > > >>>>
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>> will
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>> be
> > > > > > > > >>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>> introduced with this KIP and what will not be covered
> in
> > > > this
> > > > > KIP.
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>> Please add to it I missed anything. Will produce a
> formal
> > > > > meeting
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>
> > > > > > > > >>>>
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>> notes
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>> from next meeting onwards.
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>> Thanks,
> > > > > > > > >>>>>> Harsha
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>> On Mon, Aug 24, 2020 at 9:42 PM, Ying Zheng < yingz@
> uber.
> > > > > com.
> > > > > > > > invalid (
> > > > > > > > >>>>>> yingz@uber.com.invalid ) > wrote:
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> We did some basic feature tests at Uber. The test
> cases and
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>
> > > > > > > > >>>>
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>> results are
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> shared in this google doc:
> > > > > > > > >>>>>>> https:/ / docs. google. com/ spreadsheets/ d/ (
> > > > > > > > >>>>>>> https://docs.google.com/spreadsheets/d/ )
> > > > > > > > >>>>>>>
> > > > 1XhNJqjzwXvMCcAOhEH0sSXU6RTvyoSf93DHF-YMfGLk/edit?usp=sharing
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> The performance test results were already shared in
> the KIP
> > > > > last
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>
> > > > > > > > >>>>
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>> month.
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> On Mon, Aug 24, 2020 at 11:10 AM Harsha Ch < harsha.
> ch@
> > > > > gmail.
> > > > > > > > com (
> > > > > > > > >>>>>>> harsha.ch@gmail.com ) >
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>> wrote:
> > > > > > > > >>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> "Understand commitments towards driving design &
> > > > > implementation of
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>
> > > > > > > > >>>>
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>> the
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>> KIP
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> further and how it aligns with participant interests
> in
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>
> > > > > > > > >>>>
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>> contributing to
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>> the
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> efforts (ex: in the context of Uber’s Q3/Q4
> roadmap)." What
> > > > > is that
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>> about?
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> On Mon, Aug 24, 2020 at 11:05 AM Kowshik Prakasam <
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>> kprakasam@ confluent. io ( kprakasam@confluent.io ) >
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> wrote:
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> Hi Harsha,
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> The following google doc contains a proposal for
> temporary
> > > > > agenda
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>
> > > > > > > > >>>>
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>> for
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>> the
> > > > > > > > >>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> KIP-405 <
> https://issues.apache.org/jira/browse/KIP-405> <
> > > > > https:/ / issues. apache. org/ jira/ browse/ KIP-405
> > > > > <https://issues.apache.org/jira/browse/KIP-405> (
> > > > > > > > >>>>>>> https://issues.apache.org/jira/browse/KIP-405 ) >
> sync
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>
> > > > > > > > >>>>
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>> meeting
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> tomorrow:
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> https:/ / docs. google. com/ document/ d/ (
> > > > > > > > >>>>>>> https://docs.google.com/document/d/ )
> > > > > > > > >>>>>>> 1pqo8X5LU8TpwfC_iqSuVPezhfCfhGkbGN2TqiPA3LBU/edit
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> .
> > > > > > > > >>>>>>> Please could you add it to the Google calendar
> invite?
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> Thank you.
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> Cheers,
> > > > > > > > >>>>>>> Kowshik
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> On Thu, Aug 20, 2020 at 10:58 AM Harsha Ch < harsha.
> ch@
> > > > > gmail.
> > > > > > > > com (
> > > > > > > > >>>>>>> harsha.ch@gmail.com ) >
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>> wrote:
> > > > > > > > >>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> Hi All,
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> Scheduled a meeting for Tuesday 9am - 10am. I can
> record
> > > > and
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>
> > > > > > > > >>>>
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>> upload for
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> community to be able to follow the discussion.
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> Jun, please add the required folks on confluent side.
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> Thanks,
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> Harsha
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> On Thu, Aug 20, 2020 at 12:33 AM, Alexandre Dupriez <
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>> alexandre.dupriez@
> > > > > > > > >>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> gmail. com ( http://gmail.com/ ) > wrote:
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> Hi Jun,
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> Many thanks for your initiative.
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> If you like, I am happy to attend at the time you
> > > > suggested.
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> Many thanks,
> > > > > > > > >>>>>>> Alexandre
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> Le mer. 19 août 2020 à 22:00, Harsha Ch < harsha. ch@
> > > > > gmail. com (
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>> harsha.
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> ch@ gmail. com ( ch@gmail.com ) ) > a écrit :
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> Hi Jun,
> > > > > > > > >>>>>>> Thanks. This will help a lot. Tuesday will work for
> us.
> > > > > > > > >>>>>>> -Harsha
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> On Wed, Aug 19, 2020 at 1:24 PM Jun Rao < jun@
> confluent.
> > > > > io (
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>
> > > > > > > > >>>>
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>> jun@
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> confluent. io ( http://confluent.io/ ) ) > wrote:
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> Hi, Satish, Ying, Harsha,
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> Do you think it would be useful to have a regular
> virtual
> > > > > meeting
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>
> > > > > > > > >>>>
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>> to
> > > > > > > > >>>
> > > > > > > > >>>
> > > > > > > > >>>>
> > > > > > > > >>>>>
> > > > > > > > >>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> discuss this KIP? The goal of the meeting will be
> sharing
> > > > > > > > >>>>>>> design/development progress and discussing any open
> issues
> > > > to
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> accelerate
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> this KIP. If so, will every Tuesday (from next week)
> > > > 9am-10am
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> PT
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> work for you? I can help set up a Zoom meeting,
> invite
> > > > > everyone who
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> might
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> be interested, have it recorded and shared, etc.
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> Thanks,
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> Jun
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> On Tue, Aug 18, 2020 at 11:01 AM Satish Duggana <
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> satish. duggana@ gmail. com ( satish. duggana@
> gmail. com
> > > > (
> > > > > > > > >>>>>>> satish.duggana@gmail.com ) ) >
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> wrote:
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> Hi Kowshik,
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> Thanks for looking into the KIP and sending your
> comments.
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>>
> > > > > > > > >>>>>>> 5001. Under the section "Follower fetch protocol in
> > > > detail",
> > > > > the
> > > > > > > > >>>>>>> next-local-offset is the offset upto which the
> segments are
> > > > > copied
> > > > > > > > >>>>>>>
> > > > >
>
>

Re: [DISCUSS] KIP-405: Kafka Tiered Storage

[Satish Duggana <sa...@gmail.com>]

Hi,
We updated the KIP with the points mentioned in the earlier mail
except for KIP-516 related changes. You can go through them and let us
know if you have any comments. We will update the KIP with the
remaining todo items and KIP-516 related changes by end of this
week(5th Dec).

Thanks,
Satish.

On Tue, Nov 10, 2020 at 8:26 PM Satish Duggana <sa...@gmail.com> wrote:
>
> Hi Jun,
> Thanks for your comments. Please find the inline replies below.
>
> 605.2 "Build the local leader epoch cache by cutting the leader epoch
> sequence received from remote storage to [LSO, ELO]." I mentioned an issue
> earlier. Suppose the leader's local start offset is 100. The follower finds
> a remote segment covering offset range [80, 120). The producerState with
> this remote segment is up to offset 120. To trim the producerState to
> offset 100 requires more work since one needs to download the previous
> producerState up to offset 80 and then replay the messages from 80 to 100.
> It seems that it's simpler in this case for the follower just to take the
> remote segment as it is and start fetching from offset 120.
>
> We chose that approach to avoid any edge cases here. It may be
> possible that the remote log segment that is received may not have the
> same leader epoch sequence from 100-120 as it contains on the
> leader(this can happen due to unclean leader). It is safe to start
> from what the leader returns here.Another way is to find the remote
> log segment
>
> 5016. Just to echo what Kowshik was saying. It seems that
> RLMM.onPartitionLeadershipChanges() is only called on the replicas for a
> partition, not on the replicas for the __remote_log_segment_metadata
> partition. It's not clear how the leader of __remote_log_segment_metadata
> obtains the metadata for remote segments for deletion.
>
> RLMM will always receive the callback for the remote log metadata
> topic partitions hosted on the local broker and these will be
> subscribed. I will make this clear in the KIP.
>
> 5100. KIP-516 has been accepted and is being implemented now. Could you
> update the KIP based on topicID?
>
> We mentioned KIP-516 and how it helps. We will update this KIP with
> all the changes it brings with KIP-516.
>
> 5101. RLMM: It would be useful to clarify how the following two APIs are
> used. According to the wiki, the former is used for topic deletion and the
> latter is used for retention. It seems that retention should use the former
> since remote segments without a matching epoch in the leader (potentially
> due to unclean leader election) also need to be garbage collected. The
> latter seems to be used for the new leader to determine the last tiered
> segment.
>     default Iterator<RemoteLogSegmentMetadata>
> listRemoteLogSegments(TopicPartition topicPartition)
>     Iterator<RemoteLogSegmentMetadata> listRemoteLogSegments(TopicPartition
> topicPartition, long leaderEpoch);
>
> Right,.that is what we are currently doing. We will update the
> javadocs and wiki with that. Earlier, we did not want to remove the
> segments which are not matched with leader epochs from the ladder
> partition as they may be used later by a replica which can become a
> leader (unclean leader election) and refer those segments. But that
> may leak these segments in remote storage until the topic lifetime. We
> decided to cleanup the segments with the oldest incase of size based
> retention also.
>
> 5102. RSM:
> 5102.1 For methods like fetchLogSegmentData(), it seems that they can
> use RemoteLogSegmentId instead of RemoteLogSegmentMetadata.
>
> It will be useful to have metadata for RSM to fetch log segment. It
> may create location/path using id with other metadata too.
>
> 5102.2 In fetchLogSegmentData(), should we use long instead of Long?
>
> Wanted to keep endPosition as optional to read till the end of the
> segment and avoid sentinels.
>
> 5102.3 Why only some of the methods have default implementation and others
> Don't?
>
> Actually,  RSM will not have any default implementations. Those 3
> methods were made default earlier for tests etc. Updated the wiki.
>
> 5102.4. Could we define RemoteLogSegmentMetadataUpdate
> and DeletePartitionUpdate?
>
> Sure, they will be added.
>
>
> 5102.5 LogSegmentData: It seems that it's easier to pass
> in leaderEpochIndex as a ByteBuffer or byte array than a file since it will
> be generated in memory.
>
> Right, this is in plan.
>
> 5102.6 RemoteLogSegmentMetadata: It seems that it needs both baseOffset and
> startOffset. For example, deleteRecords() could move the startOffset to the
> middle of a segment. If we copy the full segment to remote storage, the
> baseOffset and the startOffset will be different.
>
> Good point. startOffset is baseOffset by default, if not set explicitly.
>
> 5102.7 Could we define all the public methods for RemoteLogSegmentMetadata
> and LogSegmentData?
>
> Sure, updated the wiki.
>
> 5102.8 Could we document whether endOffset in RemoteLogSegmentMetadata is
> inclusive/exclusive?
>
> It is inclusive, will update.
>
> 5103. configs:
> 5103.1 Could we define the default value of non-required configs (e.g the
> size of new thread pools)?
>
> Sure, that makes sense.
>
> 5103.2 It seems that local.log.retention.ms should default to retention.ms,
> instead of remote.log.retention.minutes. Similarly, it seems
> that local.log.retention.bytes should default to segment.bytes.
>
> Right, we do not have  remote.log.retention as we discussed earlier.
> Thanks for catching the typo.
>
> 5103.3 remote.log.manager.thread.pool.size: The description says "used in
> scheduling tasks to copy segments, fetch remote log indexes and clean up
> remote log segments". However, there is a separate
> config remote.log.reader.threads for fetching remote data. It's weird to
> fetch remote index and log in different thread pools since both are used
> for serving fetch requests.
>
> Right, remote.log.manager.thread.pool is mainly used for copy/cleanup
> activities. Fetch path always goes through remote.log.reader.threads.
>
> 5103.4 remote.log.manager.task.interval.ms: Is that the amount of time to
> back off when there is no work to do? If so, perhaps it can be renamed as
> backoff.ms.
>
> This is the delay interval for each iteration. It may be renamed to
> remote.log.manager.task.delay.ms
>
> 5103.5 Are rlm_process_interval_ms and rlm_retry_interval_ms configs? If
> so, they need to be listed in this section.
>
> remote.log.manager.task.interval.ms is the process internal, retry
> interval is missing in the configs, which will be updated in the KIP.
>
> 5104. "RLM maintains a bounded cache(possibly LRU) of the index files of
> remote log segments to avoid multiple index fetches from the remote
> storage." Is the RLM in memory or on disk? If on disk, where is it stored?
> Do we need a configuration to bound the size?
>
> It is stored on disk. They are stored in a directory
> `remote-log-index-cache` under log dir. We plan to have a config for
> that instead of default. We will have a configuration for that.
>
> 5105. The KIP uses local-log-start-offset and Earliest Local Offset in
> different places. It would be useful to standardize the terminology.
>
> Sure.
>
> 5106. The section on "In BuildingRemoteLogAux state". It listed two options
> without saying which option is chosen.
> We already mentioned in the KIP that we chose option-2.
>
> 5107. Follower to leader transition: It has step 2, but not step 1.
> Step-1 is there but it is not explicitly highlighted. It is previous
> table to step-2.
>
> 5108. If a consumer fetches from the remote data and the remote storage is
> not available, what error code is used in the fetch response?
>
> Good point. We have not yet defined the error for this case. We need
> to define an error message and send the same in fetch response.
>
> 5109. "ListOffsets: For timestamps >= 0, it returns the first message
> offset whose timestamp is >= to the given timestamp in the request. That
> means it checks in remote log time indexes first, after which local log
> time indexes are checked." Could you document which method in RLMM is used
> for this?
>
> Okay.
>
> 5110. Stopreplica: "it sets all the remote log segment metadata of that
> partition with a delete marker and publishes them to RLMM." This seems
> outdated given the new topic deletion logic.
>
> Will update with KIP-516 related points.
>
> 5111. "RLM follower fetches the earliest offset for the earliest leader
> epoch by calling RLMM.earliestLogOffset(TopicPartition topicPartition, int
> leaderEpoch) and updates that as the log start offset." Do we need that
> since replication propagates logStartOffset already?
>
> Good point. Right, existing replication protocol takes care of
> updating the followers’s log start offset received from the leader.
>
> 5112. Is the default maxWaitMs of 500ms enough for fetching from remote
> storage?
>
> Remote reads may fail within the current default wait time, but
> subsequent fetches would be able to serve as that data is stored in
> the local cache. This cache is currently implemented in RSMs. But we
> plan to pull this into the remote log messaging layer in future.
>
> 5113. "Committed offsets can be stored in a local file to avoid reading the
> messages again when a broker is restarted." Could you describe the format
> and the location of the file? Also, could the same message be processed by
> RLMM again after broker restart? If so, how do we handle that?
>
> Sure, we will update in the KIP.
>
> 5114. Message format
> 5114.1 There are two records named RemoteLogSegmentMetadataRecord with
> apiKey 0 and 1.
>
> Nice catch, that was a typo. Fixed in the wiki.
>
> 5114.2 RemoteLogSegmentMetadataRecord: Could we document whether endOffset
> is inclusive/exclusive?
> It is inclusive, will update.
>
> 5114.3 RemoteLogSegmentMetadataRecord: Could you explain LeaderEpoch a bit
> more? Is that the epoch of the leader when it copies the segment to remote
> storage? Also, how will this field be used?
>
> Right, this is the leader epoch of the broker which copied this
> segment. This is helpful in reason about which broker copied the
> segment to remote storage.
>
> 5114.4 EventTimestamp: Could you explain this a bit more? Each record in
> Kafka already has a timestamp field. Could we just use that?
>
> This is the  timestamp at which  the respective event occurred. Added
> this  to RemoteLogSegmentMetadata as RLMM can be  any other
> implementation. We thought about that but it looked cleaner to use at
> the message structure level instead of getting that from the consumer
> record and using that to build the respective event.
>
>
> 5114.5 SegmentSizeInBytes: Could this just be int32?
>
> Right, it looks like config allows only int value >= 14.
>
> 5115. RemoteLogCleaner(RLC): This could be confused with the log cleaner
> for compaction. Perhaps it can be renamed to sth like
> RemotePartitionRemover.
>
> I am fine with RemotePartitionRemover or RemoteLogDeletionManager(we
> have other manager classes like RLM, RLMM).
>
> 5116. "RLC receives the delete_partition_marked and processes it if it is
> not yet processed earlier." How does it know whether
> delete_partition_marked has been processed earlier?
>
> This is to handle duplicate delete_partition_marked events. RLC
> internally maintains a state for the delete_partition events and if it
> already has an existing event then it ignores if it is already being
> processed.
>
> 5117. Should we add a new MessageFormatter to read the tier metadata topic?
>
> Right, this is in plan but did not mention it in the KIP. This will be
> useful for debugging purposes too.
>
> 5118. "Maximum remote log reader thread pool task queue size. If the task
> queue is full, broker will stop reading remote log segments." What do we
> return to the fetch request in this case?
>
> We return an error response for that partition.
>
> 5119. It would be useful to list all things not supported in the first
> version in a Future work or Limitations section. For example, compacted
> topic, JBOD, changing remote.log.storage.enable from true to false, etc.
>
> We already have a non-goals section which is filled with some of these
> details. Do we need another limitations section?
>
> Thanks,
> Satish.
>
> On Wed, Nov 4, 2020 at 11:27 PM Jun Rao <ju...@confluent.io> wrote:
> >
> > Hi, Satish,
> >
> > Thanks for the updated KIP. A few more comments below.
> >
> > 605.2 "Build the local leader epoch cache by cutting the leader epoch
> > sequence received from remote storage to [LSO, ELO]." I mentioned an issue
> > earlier. Suppose the leader's local start offset is 100. The follower finds
> > a remote segment covering offset range [80, 120). The producerState with
> > this remote segment is up to offset 120. To trim the producerState to
> > offset 100 requires more work since one needs to download the previous
> > producerState up to offset 80 and then replay the messages from 80 to 100.
> > It seems that it's simpler in this case for the follower just to take the
> > remote segment as it is and start fetching from offset 120.
> >
> > 5016. Just to echo what Kowshik was saying. It seems that
> > RLMM.onPartitionLeadershipChanges() is only called on the replicas for a
> > partition, not on the replicas for the __remote_log_segment_metadata
> > partition. It's not clear how the leader of __remote_log_segment_metadata
> > obtains the metadata for remote segments for deletion.
> >
> > 5100. KIP-516 has been accepted and is being implemented now. Could you
> > update the KIP based on topicID?
> >
> > 5101. RLMM: It would be useful to clarify how the following two APIs are
> > used. According to the wiki, the former is used for topic deletion and the
> > latter is used for retention. It seems that retention should use the former
> > since remote segments without a matching epoch in the leader (potentially
> > due to unclean leader election) also need to be garbage collected. The
> > latter seems to be used for the new leader to determine the last tiered
> > segment.
> >     default Iterator<RemoteLogSegmentMetadata>
> > listRemoteLogSegments(TopicPartition topicPartition)
> >     Iterator<RemoteLogSegmentMetadata> listRemoteLogSegments(TopicPartition
> > topicPartition, long leaderEpoch);
> >
> > 5102. RSM:
> > 5102.1 For methods like fetchLogSegmentData(), it seems that they can
> > use RemoteLogSegmentId instead of RemoteLogSegmentMetadata.
> > 5102.2 In fetchLogSegmentData(), should we use long instead of Long?
> > 5102.3 Why only some of the methods have default implementation and others
> > don't?
> > 5102.4. Could we define RemoteLogSegmentMetadataUpdate
> > and DeletePartitionUpdate?
> > 5102.5 LogSegmentData: It seems that it's easier to pass
> > in leaderEpochIndex as a ByteBuffer or byte array than a file since it will
> > be generated in memory.
> > 5102.6 RemoteLogSegmentMetadata: It seems that it needs both baseOffset and
> > startOffset. For example, deleteRecords() could move the startOffset to the
> > middle of a segment. If we copy the full segment to remote storage, the
> > baseOffset and the startOffset will be different.
> > 5102.7 Could we define all the public methods for RemoteLogSegmentMetadata
> > and LogSegmentData?
> > 5102.8 Could we document whether endOffset in RemoteLogSegmentMetadata is
> > inclusive/exclusive?
> >
> > 5103. configs:
> > 5103.1 Could we define the default value of non-required configs (e.g the
> > size of new thread pools)?
> > 5103.2 It seems that local.log.retention.ms should default to retention.ms,
> > instead of remote.log.retention.minutes. Similarly, it seems
> > that local.log.retention.bytes should default to segment.bytes.
> > 5103.3 remote.log.manager.thread.pool.size: The description says "used in
> > scheduling tasks to copy segments, fetch remote log indexes and clean up
> > remote log segments". However, there is a separate
> > config remote.log.reader.threads for fetching remote data. It's weird to
> > fetch remote index and log in different thread pools since both are used
> > for serving fetch requests.
> > 5103.4 remote.log.manager.task.interval.ms: Is that the amount of time to
> > back off when there is no work to do? If so, perhaps it can be renamed as
> > backoff.ms.
> > 5103.5 Are rlm_process_interval_ms and rlm_retry_interval_ms configs? If
> > so, they need to be listed in this section.
> >
> > 5104. "RLM maintains a bounded cache(possibly LRU) of the index files of
> > remote log segments to avoid multiple index fetches from the remote
> > storage." Is the RLM in memory or on disk? If on disk, where is it stored?
> > Do we need a configuration to bound the size?
> >
> > 5105. The KIP uses local-log-start-offset and Earliest Local Offset in
> > different places. It would be useful to standardize the terminology.
> >
> > 5106. The section on "In BuildingRemoteLogAux state". It listed two options
> > without saying which option is chosen.
> >
> > 5107. Follower to leader transition: It has step 2, but not step 1.
> >
> > 5108. If a consumer fetches from the remote data and the remote storage is
> > not available, what error code is used in the fetch response?
> >
> > 5109. "ListOffsets: For timestamps >= 0, it returns the first message
> > offset whose timestamp is >= to the given timestamp in the request. That
> > means it checks in remote log time indexes first, after which local log
> > time indexes are checked." Could you document which method in RLMM is used
> > for this?
> >
> > 5110. Stopreplica: "it sets all the remote log segment metadata of that
> > partition with a delete marker and publishes them to RLMM." This seems
> > outdated given the new topic deletion logic.
> >
> > 5111. "RLM follower fetches the earliest offset for the earliest leader
> > epoch by calling RLMM.earliestLogOffset(TopicPartition topicPartition, int
> > leaderEpoch) and updates that as the log start offset." Do we need that
> > since replication propagates logStartOffset already?
> >
> > 5112. Is the default maxWaitMs of 500ms enough for fetching from remote
> > storage?
> >
> > 5113. "Committed offsets can be stored in a local file to avoid reading the
> > messages again when a broker is restarted." Could you describe the format
> > and the location of the file? Also, could the same message be processed by
> > RLMM again after broker restart? If so, how do we handle that?
> >
> > 5114. Message format
> > 5114.1 There are two records named RemoteLogSegmentMetadataRecord with
> > apiKey 0 and 1.
> > 5114.2 RemoteLogSegmentMetadataRecord: Could we document whether endOffset
> > is inclusive/exclusive?
> > 5114.3 RemoteLogSegmentMetadataRecord: Could you explain LeaderEpoch a bit
> > more? Is that the epoch of the leader when it copies the segment to remote
> > storage? Also, how will this field be used?
> > 5114.4 EventTimestamp: Could you explain this a bit more? Each record in
> > Kafka already has a timestamp field. Could we just use that?
> > 5114.5 SegmentSizeInBytes: Could this just be int32?
> >
> > 5115. RemoteLogCleaner(RLC): This could be confused with the log cleaner
> > for compaction. Perhaps it can be renamed to sth like
> > RemotePartitionRemover.
> >
> > 5116. "RLC receives the delete_partition_marked and processes it if it is
> > not yet processed earlier." How does it know whether
> > delete_partition_marked has been processed earlier?
> >
> > 5117. Should we add a new MessageFormatter to read the tier metadata topic?
> >
> > 5118. "Maximum remote log reader thread pool task queue size. If the task
> > queue is full, broker will stop reading remote log segments." What do we
> > return to the fetch request in this case?
> >
> > 5119. It would be useful to list all things not supported in the first
> > version in a Future work or Limitations section. For example, compacted
> > topic, JBOD, changing remote.log.storage.enable from true to false, etc.
> >
> > Thanks,
> >
> > Jun
> >
> > On Tue, Oct 27, 2020 at 5:57 PM Kowshik Prakasam <kp...@confluent.io>
> > wrote:
> >
> > > Hi Satish,
> > >
> > > Thanks for the updates to the KIP. Here are my first batch of
> > > comments/suggestions on the latest version of the KIP.
> > >
> > > 5012. In the RemoteStorageManager interface, there is an API defined for
> > > each file type. For example, fetchOffsetIndex, fetchTimestampIndex etc. To
> > > avoid the duplication, I'd suggest we can instead have a FileType enum and
> > > a common get API based on the FileType.
> > >
> > > 5013. There are some references to the Google doc in the KIP. I wasn't sure
> > > if the Google doc is expected to be in sync with the contents of the wiki.
> > > Going forward, it seems easier if just the KIP is maintained as the source
> > > of truth. In this regard, could you please move all the references to the
> > > Google doc, maybe to a separate References section at the bottom of the
> > > KIP?
> > >
> > > 5014. There are some TODO sections in the KIP. Would these be filled up in
> > > future iterations?
> > >
> > > 5015. Under "Topic deletion lifecycle", I'm trying to understand why do we
> > > need delete_partition_marked as well as the delete_partition_started
> > > messages. I couldn't spot a drawback if supposing we simplified the design
> > > such that the controller would only write delete_partition_started message,
> > > and RemoteLogCleaner (RLC) instance picks it up for processing. What am I
> > > missing?
> > >
> > > 5016. Under "Topic deletion lifecycle", step (4) is mentioned as "RLC gets
> > > all the remote log segments for the partition and each of these remote log
> > > segments is deleted with the next steps.". Since the RLC instance runs on
> > > each tier topic partition leader, how does the RLC then get the list of
> > > remote log segments to be deleted? It will be useful to add that detail to
> > > the KIP.
> > >
> > > 5017. Under "Public Interfaces -> Configs", there is a line mentioning "We
> > > will support flipping remote.log.storage.enable in next versions." It will
> > > be useful to mention this in the "Future Work" section of the KIP too.
> > >
> > > 5018. The KIP introduces a number of configuration parameters. It will be
> > > useful to mention in the KIP if the user should assume these as static
> > > configuration in the server.properties file, or dynamic configuration which
> > > can be modified without restarting the broker.
> > >
> > > 5019.  Maybe this is planned as a future update to the KIP, but I thought
> > > I'd mention it here. Could you please add details to the KIP on why RocksDB
> > > was chosen as the default cache implementation of RLMM, and how it is going
> > > to be used? Were alternatives compared/considered? For example, it would be
> > > useful to explain/evaluate the following: 1) debuggability of the RocksDB
> > > JNI interface, 2) performance, 3) portability across platforms and 4)
> > > interface parity of RocksDB’s JNI api with it's underlying C/C++ api.
> > >
> > > 5020. Following up on (5019), for the RocksDB cache, it will be useful to
> > > explain the relationship/mapping between the following in the KIP: 1) # of
> > > tiered partitions, 2) # of partitions of metadata topic
> > > __remote_log_metadata and 3) # of RocksDB instances. i.e. is the plan to
> > > have a RocksDB instance per tiered partition, or per metadata topic
> > > partition, or just 1 for per broker?
> > >
> > > 5021. I was looking at the implementation prototype (PR link:
> > > https://github.com/apache/kafka/pull/7561). It seems that a boolean
> > > attribute is being introduced into the Log layer to check if remote log
> > > capability is enabled. While the boolean footprint is small at the moment,
> > > this can easily grow in the future and become harder to
> > > test/maintain, considering that the Log layer is already pretty complex. We
> > > should start thinking about how to manage such changes to the Log layer
> > > (for the purpose of improved testability, better separation of concerns and
> > > readability). One proposal I have is to take a step back and define a
> > > higher level Log interface. Then, the Broker code can be changed to use
> > > this interface. It can be changed such that only a handle to the interface
> > > is exposed to other components (such as LogCleaner, ReplicaManager etc.)
> > > and not the underlying Log object. This approach keeps the user of the Log
> > > layer agnostic of the whereabouts of the data. Underneath the interface,
> > > the implementing classes can completely separate local log capabilities
> > > from the remote log. For example, the Log class can be simplified to only
> > > manage logic surrounding local log segments and metadata. Additionally, a
> > > wrapper class can be provided (implementing the higher level Log interface)
> > > which will contain any/all logic surrounding tiered data. The wrapper
> > > class will wrap around an instance of the Log class delegating the local
> > > log logic to it. Finally, a handle to the wrapper class can be exposed to
> > > the other components wherever they need a handle to the higher level Log
> > > interface.
> > >
> > >
> > > Cheers,
> > > Kowshik
> > >
> > > On Mon, Oct 26, 2020 at 9:52 PM Satish Duggana <sa...@gmail.com>
> > > wrote:
> > >
> > > > Hi,
> > > > KIP is updated with 1) topic deletion lifecycle and its related items
> > > > 2) Protocol changes(mainly related to ListOffsets) and other minor
> > > > changes.
> > > > Please go through them and let us know your comments.
> > > >
> > > > Thanks,
> > > > Satish.
> > > >
> > > > On Mon, Sep 28, 2020 at 9:10 PM Satish Duggana <satish.duggana@gmail.com
> > > >
> > > > wrote:
> > > > >
> > > > > Hi Dhruvil,
> > > > > Thanks for looking into the KIP and sending your comments. Sorry for
> > > > > the late reply, missed it in the mail thread.
> > > > >
> > > > > 1. Could you describe how retention would work with this KIP and which
> > > > > threads are responsible for driving this work? I believe there are 3
> > > > kinds
> > > > > of retention processes we are looking at:
> > > > >   (a) Regular retention for data in tiered storage as per configured `
> > > > > retention.ms` / `retention.bytes`.
> > > > >   (b) Local retention for data in local storage as per configured `
> > > > > local.log.retention.ms` / `local.log.retention.bytes`
> > > > >   (c) Possibly regular retention for data in local storage, if the
> > > > tiering
> > > > > task is lagging or for data that is below the log start offset.
> > > > >
> > > > > Local log retention is done by the existing log cleanup tasks. These
> > > > > are not done for segments that are not yet copied to remote storage.
> > > > > Remote log cleanup is done by the leader partition’s RLMTask.
> > > > >
> > > > > 2. When does a segment become eligible to be tiered? Is it as soon as
> > > the
> > > > > segment is rolled and the end offset is less than the last stable
> > > offset
> > > > as
> > > > > mentioned in the KIP? I wonder if we need to consider other parameters
> > > > too,
> > > > > like the highwatermark so that we are guaranteed that what we are
> > > tiering
> > > > > has been committed to the log and accepted by the ISR.
> > > > >
> > > > > AFAIK, last stable offset is always <= highwatermark. This will make
> > > > > sure we are always tiering the message segments which have been
> > > > > accepted by ISR and transactionally completed.
> > > > >
> > > > >
> > > > > 3. The section on "Follower Fetch Scenarios" is useful but is a bit
> > > > > difficult to parse at the moment. It would be useful to summarize the
> > > > > changes we need in the ReplicaFetcher.
> > > > >
> > > > > It may become difficult for users to read/follow if we add code changes
> > > > here.
> > > > >
> > > > > 4. Related to the above, it's a bit unclear how we are planning on
> > > > > restoring the producer state for a new replica. Could you expand on
> > > that?
> > > > >
> > > > > It is mentioned in the KIP BuildingRemoteLogAuxState is introduced to
> > > > > build the state like leader epoch sequence and producer snapshots
> > > > > before it starts fetching the data from the leader. We will make it
> > > > > clear in the KIP.
> > > > >
> > > > >
> > > > > 5. Similarly, it would be worth summarizing the behavior on unclean
> > > > leader
> > > > > election. There are several scenarios to consider here: data loss from
> > > > > local log, data loss from remote log, data loss from metadata topic,
> > > etc.
> > > > > It's worth describing these in detail.
> > > > >
> > > > > We mentioned the cases about unclean leader election in the follower
> > > > > fetch scenarios.
> > > > > If there are errors while fetching data from remote store or metadata
> > > > > store, it will work the same way as it works with local log. It
> > > > > returns the error back to the caller. Please let us know if I am
> > > > > missing your point here.
> > > > >
> > > > >
> > > > > 7. For a READ_COMMITTED FetchRequest, how do we retrieve and return the
> > > > > aborted transaction metadata?
> > > > >
> > > > > When a fetch for a remote log is accessed, we will fetch aborted
> > > > > transactions along with the segment if it is not found in the local
> > > > > index cache. This includes the case of transaction index not existing
> > > > > in the remote log segment. That means, the cache entry can be empty or
> > > > > have a list of aborted transactions.
> > > > >
> > > > >
> > > > > 8. The `LogSegmentData` class assumes that we have a log segment,
> > > offset
> > > > > index, time index, transaction index, producer snapshot and leader
> > > epoch
> > > > > index. How do we deal with cases where we do not have one or more of
> > > > these?
> > > > > For example, we may not have a transaction index or producer snapshot
> > > > for a
> > > > > particular segment. The former is optional, and the latter is only kept
> > > > for
> > > > > up to the 3 latest segments.
> > > > >
> > > > > This is a good point,  we discussed this in the last meeting.
> > > > > Transaction index is optional and we will copy them only if it exists.
> > > > > We want to keep all the producer snapshots at each log segment rolling
> > > > > and they can be removed if the log copying is successful and it still
> > > > > maintains the existing latest 3 segments, We only delete the producer
> > > > > snapshots which have been copied to remote log segments on leader.
> > > > > Follower will keep the log segments beyond the segments which have not
> > > > > been copied to remote storage. We will update the KIP with these
> > > > > details.
> > > > >
> > > > > Thanks,
> > > > > Satish.
> > > > >
> > > > > On Thu, Sep 17, 2020 at 1:47 AM Dhruvil Shah <dh...@confluent.io>
> > > > wrote:
> > > > > >
> > > > > > Hi Satish, Harsha,
> > > > > >
> > > > > > Thanks for the KIP. Few questions below:
> > > > > >
> > > > > > 1. Could you describe how retention would work with this KIP and
> > > which
> > > > > > threads are responsible for driving this work? I believe there are 3
> > > > kinds
> > > > > > of retention processes we are looking at:
> > > > > >   (a) Regular retention for data in tiered storage as per configured
> > > `
> > > > > > retention.ms` / `retention.bytes`.
> > > > > >   (b) Local retention for data in local storage as per configured `
> > > > > > local.log.retention.ms` / `local.log.retention.bytes`
> > > > > >   (c) Possibly regular retention for data in local storage, if the
> > > > tiering
> > > > > > task is lagging or for data that is below the log start offset.
> > > > > >
> > > > > > 2. When does a segment become eligible to be tiered? Is it as soon as
> > > > the
> > > > > > segment is rolled and the end offset is less than the last stable
> > > > offset as
> > > > > > mentioned in the KIP? I wonder if we need to consider other
> > > parameters
> > > > too,
> > > > > > like the highwatermark so that we are guaranteed that what we are
> > > > tiering
> > > > > > has been committed to the log and accepted by the ISR.
> > > > > >
> > > > > > 3. The section on "Follower Fetch Scenarios" is useful but is a bit
> > > > > > difficult to parse at the moment. It would be useful to summarize the
> > > > > > changes we need in the ReplicaFetcher.
> > > > > >
> > > > > > 4. Related to the above, it's a bit unclear how we are planning on
> > > > > > restoring the producer state for a new replica. Could you expand on
> > > > that?
> > > > > >
> > > > > > 5. Similarly, it would be worth summarizing the behavior on unclean
> > > > leader
> > > > > > election. There are several scenarios to consider here: data loss
> > > from
> > > > > > local log, data loss from remote log, data loss from metadata topic,
> > > > etc.
> > > > > > It's worth describing these in detail.
> > > > > >
> > > > > > 6. It would be useful to add details about how we plan on using
> > > > RocksDB in
> > > > > > the default implementation of `RemoteLogMetadataManager`.
> > > > > >
> > > > > > 7. For a READ_COMMITTED FetchRequest, how do we retrieve and return
> > > the
> > > > > > aborted transaction metadata?
> > > > > >
> > > > > > 8. The `LogSegmentData` class assumes that we have a log segment,
> > > > offset
> > > > > > index, time index, transaction index, producer snapshot and leader
> > > > epoch
> > > > > > index. How do we deal with cases where we do not have one or more of
> > > > these?
> > > > > > For example, we may not have a transaction index or producer snapshot
> > > > for a
> > > > > > particular segment. The former is optional, and the latter is only
> > > > kept for
> > > > > > up to the 3 latest segments.
> > > > > >
> > > > > > Thanks,
> > > > > > Dhruvil
> > > > > >
> > > > > > On Mon, Sep 7, 2020 at 6:54 PM Harsha Ch <ha...@gmail.com>
> > > wrote:
> > > > > >
> > > > > > > Hi All,
> > > > > > >
> > > > > > > We are all working through the last meeting feedback. I'll cancel
> > > the
> > > > > > > tomorrow 's meeting and we can meanwhile continue our discussion in
> > > > mailing
> > > > > > > list. We can start the regular meeting from next week onwards.
> > > > > > >
> > > > > > > Thanks,
> > > > > > >
> > > > > > > Harsha
> > > > > > >
> > > > > > > On Fri, Sep 04, 2020 at 8:41 AM, Satish Duggana <
> > > > satish.duggana@gmail.com
> > > > > > > > wrote:
> > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > Hi Jun,
> > > > > > > > Thanks for your thorough review and comments. Please find the
> > > > inline
> > > > > > > > replies below.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > 600. The topic deletion logic needs more details.
> > > > > > > > 600.1 The KIP mentions "The controller considers the topic
> > > > partition is
> > > > > > > > deleted only when it determines that there are no log segments
> > > for
> > > > that
> > > > > > > > topic partition by using RLMM". How is this done?
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > It uses RLMM#listSegments() returns all the segments for the
> > > given
> > > > topic
> > > > > > > > partition.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > 600.2 "If the delete option is enabled then the leader will stop
> > > > RLM task
> > > > > > > > and stop processing and it sets all the remote log segment
> > > > metadata of
> > > > > > > > that partition with a delete marker and publishes them to RLMM."
> > > We
> > > > > > > > discussed this earlier. When a topic is being deleted, there may
> > > > not be a
> > > > > > > > leader for the deleted partition.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > This is a good point. As suggested in the meeting, we will add a
> > > > separate
> > > > > > > > section for topic/partition deletion lifecycle and this scenario
> > > > will be
> > > > > > > > addressed.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > 601. Unclean leader election
> > > > > > > > 601.1 Scenario 1: new empty follower
> > > > > > > > After step 1, the follower restores up to offset 3. So why does
> > > it
> > > > have
> > > > > > > > LE-2 <https://issues.apache.org/jira/browse/LE-2> at offset 5?
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > Nice catch. It was showing the leader epoch fetched from the
> > > remote
> > > > > > > > storage. It should be shown with the truncated till offset 3.
> > > > Updated the
> > > > > > > > KIP.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > 601.2 senario 5: After Step 3, leader A has inconsistent data
> > > > between its
> > > > > > > > local and the tiered data. For example. offset 3 has msg 3 LE-0
> > > > <https://issues.apache.org/jira/browse/LE-0> locally,
> > > > > > > > but msg 5 LE-1 <https://issues.apache.org/jira/browse/LE-1> in
> > > > the remote store. While it's ok for the unclean leader
> > > > > > > > to lose data, it should still return consistent data, whether
> > > it's
> > > > from
> > > > > > > > the local or the remote store.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > There is no inconsistency here as LE-0
> > > > <https://issues.apache.org/jira/browse/LE-0> offsets are [0, 4] and LE-2
> > > > <https://issues.apache.org/jira/browse/LE-2>:
> > > > > > > > [5, ]. It will always get the right records for the given offset
> > > > and
> > > > > > > > leader epoch. In case of remote, RSM is invoked to get the remote
> > > > log
> > > > > > > > segment that contains the given offset with the leader epoch.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > 601.4 It seems that retention is based on
> > > > > > > > listRemoteLogSegments(TopicPartition topicPartition, long
> > > > leaderEpoch).
> > > > > > > > When there is an unclean leader election, it's possible for the
> > > new
> > > > > > > leader
> > > > > > > > to not to include certain epochs in its epoch cache. How are
> > > remote
> > > > > > > > segments associated with those epochs being cleaned?
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > That is a good point. This leader will also cleanup the epochs
> > > > earlier to
> > > > > > > > its start leader epoch and delete those segments. It gets the
> > > > earliest
> > > > > > > > epoch for a partition and starts deleting segments from that
> > > leader
> > > > > > > epoch.
> > > > > > > > We need one more API in RLMM to get the earliest leader epoch.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > 601.5 The KIP discusses the handling of unclean leader elections
> > > > for user
> > > > > > > > topics. What about unclean leader elections on
> > > > > > > > __remote_log_segment_metadata?
> > > > > > > > This is the same as other system topics like consumer_offsets,
> > > > > > > > __transaction_state topics. As discussed in the meeting, we will
> > > > add the
> > > > > > > > behavior of __remote_log_segment_metadata topic’s unclean leader
> > > > > > > > truncation.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > 602. It would be useful to clarify the limitations in the initial
> > > > > > > release.
> > > > > > > > The KIP mentions not supporting compacted topics. What about JBOD
> > > > and
> > > > > > > > changing the configuration of a topic from delete to compact
> > > after
> > > > > > > remote.
> > > > > > > > log. storage. enable ( http://remote.log.storage.enable/ ) is
> > > > enabled?
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > This was updated in the KIP earlier.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > 603. RLM leader tasks:
> > > > > > > > 603.1"It checks for rolled over LogSegments (which have the last
> > > > message
> > > > > > > > offset less than last stable offset of that topic partition) and
> > > > copies
> > > > > > > > them along with their offset/time/transaction indexes and leader
> > > > epoch
> > > > > > > > cache to the remote tier." It needs to copy the producer snapshot
> > > > too.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > Right. It copies producer snapshots too as mentioned in
> > > > LogSegmentData.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > 603.2 "Local logs are not cleaned up till those segments are
> > > copied
> > > > > > > > successfully to remote even though their retention time/size is
> > > > reached"
> > > > > > > > This seems weird. If the tiering stops because the remote store
> > > is
> > > > not
> > > > > > > > available, we don't want the local data to grow forever.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > It was clarified in the discussion that the comment was more
> > > about
> > > > the
> > > > > > > > local storage goes beyond the log.retention. The above statement
> > > > is about
> > > > > > > > local.log.retention but not for the complete log.retention. When
> > > it
> > > > > > > > reaches the log.retention then it will delete the local logs even
> > > > though
> > > > > > > > those are not copied to remote storage.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > 604. "RLM maintains a bounded cache(possibly LRU) of the index
> > > > files of
> > > > > > > > remote log segments to avoid multiple index fetches from the
> > > remote
> > > > > > > > storage. These indexes can be used in the same way as local
> > > segment
> > > > > > > > indexes are used." Could you provide more details on this? Are
> > > the
> > > > > > > indexes
> > > > > > > > cached in memory or on disk? If on disk, where are they stored?
> > > > Are the
> > > > > > > > cached indexes bound by a certain size?
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > These are cached on disk and stored in log.dir with a name
> > > > > > > > “__remote_log_index_cache”. They are bound by the total size.
> > > This
> > > > will
> > > > > > > be
> > > > > > > > exposed as a user configuration,
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > 605. BuildingRemoteLogAux
> > > > > > > > 605.1 In this section, two options are listed. Which one is
> > > chosen?
> > > > > > > > Option-2, updated the KIP.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > 605.2 In option 2, it says "Build the local leader epoch cache by
> > > > cutting
> > > > > > > > the leader epoch sequence received from remote storage to [LSO,
> > > > ELO].
> > > > > > > (LSO
> > > > > > > >
> > > > > > > > = log start offset)." We need to do the same thing for the
> > > producer
> > > > > > > > snapshot. However, it's hard to cut the producer snapshot to an
> > > > earlier
> > > > > > > > offset. Another option is to simply take the lastOffset from the
> > > > remote
> > > > > > > > segment and use that as the starting fetch offset in the
> > > follower.
> > > > This
> > > > > > > > avoids the need for cutting.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > Right, this was mentioned in the “transactional support” section
> > > > about
> > > > > > > > adding these details.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > 606. ListOffsets: Since we need a version bump, could you
> > > document
> > > > it
> > > > > > > > under a protocol change section?
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > Sure, we will update the KIP.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > 607. "LogStartOffset of a topic can point to either of local
> > > > segment or
> > > > > > > > remote segment but it is initialised and maintained in the Log
> > > > class like
> > > > > > > > now. This is already maintained in `Log` class while loading the
> > > > logs and
> > > > > > > > it can also be fetched from RemoteLogMetadataManager." What will
> > > > happen
> > > > > > > to
> > > > > > > > the existing logic (e.g. log recovery) that currently depends on
> > > > > > > > logStartOffset but assumes it's local?
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > They use a field called localLogStartOffset which is the local
> > > log
> > > > start
> > > > > > > > offset..
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > 608. Handle expired remote segment: How does it pick up new
> > > > > > > logStartOffset
> > > > > > > > from deleteRecords?
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > Good point. This was not addressed in the KIP. Will update the
> > > KIP
> > > > on how
> > > > > > > > the RLM task handles this scenario.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > 609. RLMM message format:
> > > > > > > > 609.1 It includes both MaxTimestamp and EventTimestamp. Where
> > > does
> > > > it get
> > > > > > > > both since the message in the log only contains one timestamp?
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > `EventTimeStamp` is the timestamp at which that segment metadata
> > > > event is
> > > > > > > > generated. This is more for audits.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > 609.2 If we change just the state (e.g. to DELETE_STARTED), it
> > > > seems it's
> > > > > > > > wasteful to have to include all other fields not changed.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > This is a good point. We thought about incremental updates. But
> > > we
> > > > want
> > > > > > > to
> > > > > > > > make sure all the events are in the expected order and take
> > > action
> > > > based
> > > > > > > > on the latest event. Will think through the approaches in detail
> > > > and
> > > > > > > > update here.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > 609.3 Could you document which process makes the following
> > > > transitions
> > > > > > > > DELETE_MARKED, DELETE_STARTED, DELETE_FINISHED?
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > Okay, will document more details.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > 610. remote.log.reader.max.pending.tasks: "Maximum remote log
> > > > reader
> > > > > > > > thread pool task queue size. If the task queue is full, broker
> > > > will stop
> > > > > > > > reading remote log segments." What does the broker do if the
> > > queue
> > > > is
> > > > > > > > full?
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > It returns an error for this topic partition.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > 611. What do we return if the request offset/epoch doesn't exist
> > > > in the
> > > > > > > > following API?
> > > > > > > > RemoteLogSegmentMetadata remoteLogSegmentMetadata(TopicPartition
> > > > > > > > topicPartition, long offset, int epochForOffset)
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > This returns null. But we prefer to update the return type as
> > > > Optional
> > > > > > > and
> > > > > > > > return Empty if that does not exist.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > Thanks,
> > > > > > > > Satish.
> > > > > > > >
> > > > > > > >
> > > > > > > >
> > > > > > > > On Tue, Sep 1, 2020 at 9:45 AM Jun Rao < jun@ confluent. io (
> > > > > > > > jun@confluent.io ) > wrote:
> > > > > > > >
> > > > > > > >
> > > > > > > >>
> > > > > > > >>
> > > > > > > >> Hi, Satish,
> > > > > > > >>
> > > > > > > >>
> > > > > > > >>
> > > > > > > >> Thanks for the updated KIP. Made another pass. A few more
> > > comments
> > > > > > > below.
> > > > > > > >>
> > > > > > > >>
> > > > > > > >>
> > > > > > > >> 600. The topic deletion logic needs more details.
> > > > > > > >> 600.1 The KIP mentions "The controller considers the topic
> > > > partition is
> > > > > > > >> deleted only when it determines that there are no log segments
> > > > for that
> > > > > > > >> topic partition by using RLMM". How is this done? 600.2 "If the
> > > > delete
> > > > > > > >> option is enabled then the leader will stop RLM task and stop
> > > > processing
> > > > > > > >> and it sets all the remote log segment metadata of that
> > > partition
> > > > with a
> > > > > > > >> delete marker and publishes them to RLMM." We discussed this
> > > > earlier.
> > > > > > > When
> > > > > > > >> a topic is being deleted, there may not be a leader for the
> > > > deleted
> > > > > > > >> partition.
> > > > > > > >>
> > > > > > > >>
> > > > > > > >>
> > > > > > > >> 601. Unclean leader election
> > > > > > > >> 601.1 Scenario 1: new empty follower
> > > > > > > >> After step 1, the follower restores up to offset 3. So why does
> > > > it have
> > > > > > > >> LE-2 <https://issues.apache.org/jira/browse/LE-2> at offset 5?
> > > > > > > >> 601.2 senario 5: After Step 3, leader A has inconsistent data
> > > > between
> > > > > > > its
> > > > > > > >> local and the tiered data. For example. offset 3 has msg 3 LE-0
> > > > <https://issues.apache.org/jira/browse/LE-0> locally,
> > > > > > > >> but msg 5 LE-1 <https://issues.apache.org/jira/browse/LE-1> in
> > > > the remote store. While it's ok for the unclean leader
> > > > > > > >> to lose data, it should still return consistent data, whether
> > > > it's from
> > > > > > > >> the local or the remote store.
> > > > > > > >> 601.3 The follower picks up log start offset using the following
> > > > api.
> > > > > > > >> Suppose that we have 3 remote segments (LE, SegmentStartOffset)
> > > > as (2,
> > > > > > > >> 10),
> > > > > > > >> (3, 20) and (7, 15) due to an unclean leader election. Using the
> > > > > > > following
> > > > > > > >> api will cause logStartOffset to go backward from 20 to 15. How
> > > > do we
> > > > > > > >> prevent that?
> > > > > > > >> earliestLogOffset(TopicPartition topicPartition, int
> > > leaderEpoch)
> > > > 601.4
> > > > > > > It
> > > > > > > >> seems that retention is based on
> > > > > > > >> listRemoteLogSegments(TopicPartition topicPartition, long
> > > > leaderEpoch).
> > > > > > > >> When there is an unclean leader election, it's possible for the
> > > > new
> > > > > > > leader
> > > > > > > >> to not to include certain epochs in its epoch cache. How are
> > > > remote
> > > > > > > >> segments associated with those epochs being cleaned? 601.5 The
> > > KIP
> > > > > > > >> discusses the handling of unclean leader elections for user
> > > > topics. What
> > > > > > > >> about unclean leader elections on
> > > > > > > >> __remote_log_segment_metadata?
> > > > > > > >>
> > > > > > > >>
> > > > > > > >>
> > > > > > > >> 602. It would be useful to clarify the limitations in the
> > > initial
> > > > > > > release.
> > > > > > > >> The KIP mentions not supporting compacted topics. What about
> > > JBOD
> > > > and
> > > > > > > >> changing the configuration of a topic from delete to compact
> > > after
> > > > > > > remote.
> > > > > > > >> log. storage. enable ( http://remote.log.storage.enable/ ) is
> > > > enabled?
> > > > > > > >>
> > > > > > > >>
> > > > > > > >>
> > > > > > > >> 603. RLM leader tasks:
> > > > > > > >> 603.1"It checks for rolled over LogSegments (which have the last
> > > > message
> > > > > > > >> offset less than last stable offset of that topic partition) and
> > > > copies
> > > > > > > >> them along with their offset/time/transaction indexes and leader
> > > > epoch
> > > > > > > >> cache to the remote tier." It needs to copy the producer
> > > snapshot
> > > > too.
> > > > > > > >> 603.2 "Local logs are not cleaned up till those segments are
> > > > copied
> > > > > > > >> successfully to remote even though their retention time/size is
> > > > reached"
> > > > > > > >> This seems weird. If the tiering stops because the remote store
> > > > is not
> > > > > > > >> available, we don't want the local data to grow forever.
> > > > > > > >>
> > > > > > > >>
> > > > > > > >>
> > > > > > > >> 604. "RLM maintains a bounded cache(possibly LRU) of the index
> > > > files of
> > > > > > > >> remote log segments to avoid multiple index fetches from the
> > > > remote
> > > > > > > >> storage. These indexes can be used in the same way as local
> > > > segment
> > > > > > > >> indexes are used." Could you provide more details on this? Are
> > > the
> > > > > > > indexes
> > > > > > > >> cached in memory or on disk? If on disk, where are they stored?
> > > > Are the
> > > > > > > >> cached indexes bound by a certain size?
> > > > > > > >>
> > > > > > > >>
> > > > > > > >>
> > > > > > > >> 605. BuildingRemoteLogAux
> > > > > > > >> 605.1 In this section, two options are listed. Which one is
> > > > chosen?
> > > > > > > 605.2
> > > > > > > >> In option 2, it says "Build the local leader epoch cache by
> > > > cutting the
> > > > > > > >> leader epoch sequence received from remote storage to [LSO,
> > > ELO].
> > > > (LSO
> > > > > > > >> = log start offset)." We need to do the same thing for the
> > > > producer
> > > > > > > >> snapshot. However, it's hard to cut the producer snapshot to an
> > > > earlier
> > > > > > > >> offset. Another option is to simply take the lastOffset from the
> > > > remote
> > > > > > > >> segment and use that as the starting fetch offset in the
> > > > follower. This
> > > > > > > >> avoids the need for cutting.
> > > > > > > >>
> > > > > > > >>
> > > > > > > >>
> > > > > > > >> 606. ListOffsets: Since we need a version bump, could you
> > > > document it
> > > > > > > >> under a protocol change section?
> > > > > > > >>
> > > > > > > >>
> > > > > > > >>
> > > > > > > >> 607. "LogStartOffset of a topic can point to either of local
> > > > segment or
> > > > > > > >> remote segment but it is initialised and maintained in the Log
> > > > class
> > > > > > > like
> > > > > > > >> now. This is already maintained in `Log` class while loading the
> > > > logs
> > > > > > > and
> > > > > > > >> it can also be fetched from RemoteLogMetadataManager." What will
> > > > happen
> > > > > > > to
> > > > > > > >> the existing logic (e.g. log recovery) that currently depends on
> > > > > > > >> logStartOffset but assumes it's local?
> > > > > > > >>
> > > > > > > >>
> > > > > > > >>
> > > > > > > >> 608. Handle expired remote segment: How does it pick up new
> > > > > > > logStartOffset
> > > > > > > >> from deleteRecords?
> > > > > > > >>
> > > > > > > >>
> > > > > > > >>
> > > > > > > >> 609. RLMM message format:
> > > > > > > >> 609.1 It includes both MaxTimestamp and EventTimestamp. Where
> > > > does it
> > > > > > > get
> > > > > > > >> both since the message in the log only contains one timestamp?
> > > > 609.2 If
> > > > > > > we
> > > > > > > >> change just the state (e.g. to DELETE_STARTED), it seems it's
> > > > wasteful
> > > > > > > to
> > > > > > > >> have to include all other fields not changed. 609.3 Could you
> > > > document
> > > > > > > >> which process makes the following transitions DELETE_MARKED,
> > > > > > > >> DELETE_STARTED, DELETE_FINISHED?
> > > > > > > >>
> > > > > > > >>
> > > > > > > >>
> > > > > > > >> 610. remote.log.reader.max.pending.tasks: "Maximum remote log
> > > > reader
> > > > > > > >> thread pool task queue size. If the task queue is full, broker
> > > > will stop
> > > > > > > >> reading remote log segments." What does the broker do if the
> > > > queue is
> > > > > > > >> full?
> > > > > > > >>
> > > > > > > >>
> > > > > > > >>
> > > > > > > >> 611. What do we return if the request offset/epoch doesn't exist
> > > > in the
> > > > > > > >> following API?
> > > > > > > >> RemoteLogSegmentMetadata remoteLogSegmentMetadata(TopicPartition
> > > > > > > >> topicPartition, long offset, int epochForOffset)
> > > > > > > >>
> > > > > > > >>
> > > > > > > >>
> > > > > > > >> Jun
> > > > > > > >>
> > > > > > > >>
> > > > > > > >>
> > > > > > > >> On Mon, Aug 31, 2020 at 11:19 AM Satish Duggana < satish.
> > > duggana@
> > > > > > > gmail. com
> > > > > > > >> ( satish.duggana@gmail.com ) > wrote:
> > > > > > > >>
> > > > > > > >>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>> KIP is updated with
> > > > > > > >>> - Remote log segment metadata topic message format/schema.
> > > > > > > >>> - Added remote log segment metadata state transitions and
> > > > explained how
> > > > > > > >>> the deletion of segments is handled, including the case of
> > > > partition
> > > > > > > >>> deletions.
> > > > > > > >>> - Added a few more limitations in the "Non goals" section.
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>> Thanks,
> > > > > > > >>> Satish.
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>> On Thu, Aug 27, 2020 at 12:42 AM Harsha Ch < harsha. ch@
> > > gmail.
> > > > com (
> > > > > > > >>> harsha.ch@gmail.com ) > wrote:
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>>
> > > > > > > >>>>
> > > > > > > >>>> Updated the KIP with Meeting Notes section
> > > > > > > >>>>
> > > > > > > >>>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>> https:/ / cwiki. apache. org/ confluence/ display/ KAFKA/
> > > > > > > KIP-405 <https://issues.apache.org/jira/browse/KIP-405>
> > > > %3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> > > > > > > >>> (
> > > > > > > >>>
> > > > > > >
> > > >
> > > https://cwiki.apache.org/confluence/display/KAFKA/KIP-405%3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> > > > > > > >>> )
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>>
> > > > > > > >>>>
> > > > > > > >>>> On Tue, Aug 25, 2020 at 1:03 PM Jun Rao < jun@ confluent. io
> > > (
> > > > > > > >>>> jun@confluent.io ) > wrote:
> > > > > > > >>>>
> > > > > > > >>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>> Hi, Harsha,
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>> Thanks for the summary. Could you add the summary and the
> > > > recording
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>
> > > > > > > >>>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>> link to
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>> the last section of
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>
> > > > > > > >>>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>> https:/ / cwiki. apache. org/ confluence/ display/ KAFKA/
> > > > > > > Kafka+Improvement+Proposals
> > > > > > > >>> (
> > > > > > > >>>
> > > > > > >
> > > >
> > > https://cwiki.apache.org/confluence/display/KAFKA/Kafka+Improvement+Proposals
> > > > > > > >>> )
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>> ?
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>> Jun
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>> On Tue, Aug 25, 2020 at 11:12 AM Harsha Chintalapani < kafka@
> > > > > > > harsha. io (
> > > > > > > >>>>> kafka@harsha.io ) > wrote:
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>> Thanks everyone for attending the meeting today.
> > > > > > > >>>>>> Here is the recording
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>
> > > > > > > >>>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>> https:/ / drive. google. com/ file/ d/
> > > > > > > 14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/ view?usp=sharing
> > > > > > > >>> (
> > > > > > > >>>
> > > > > > >
> > > >
> > > https://drive.google.com/file/d/14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/view?usp=sharing
> > > > > > > >>> )
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>>
> > > > > > > >>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>> Notes:
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>> 1. KIP is updated with follower fetch protocol and ready to
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>
> > > > > > > >>>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>> reviewed
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>>
> > > > > > > >>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>> 2. Satish to capture schema of internal metadata topic in
> > > the
> > > > KIP
> > > > > > > >>>>>> 3. We will update the KIP with details of different cases
> > > > > > > >>>>>> 4. Test plan will be captured in a doc and will add to the
> > > KIP
> > > > > > > >>>>>> 5. Add a section "Limitations" to capture the capabilities
> > > > that
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>
> > > > > > > >>>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>> will
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>> be
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>> introduced with this KIP and what will not be covered in
> > > this
> > > > KIP.
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>> Please add to it I missed anything. Will produce a formal
> > > > meeting
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>
> > > > > > > >>>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>> notes
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>>
> > > > > > > >>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>> from next meeting onwards.
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>> Thanks,
> > > > > > > >>>>>> Harsha
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>> On Mon, Aug 24, 2020 at 9:42 PM, Ying Zheng < yingz@ uber.
> > > > com.
> > > > > > > invalid (
> > > > > > > >>>>>> yingz@uber.com.invalid ) > wrote:
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> We did some basic feature tests at Uber. The test cases and
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>
> > > > > > > >>>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>> results are
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>>
> > > > > > > >>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> shared in this google doc:
> > > > > > > >>>>>>> https:/ / docs. google. com/ spreadsheets/ d/ (
> > > > > > > >>>>>>> https://docs.google.com/spreadsheets/d/ )
> > > > > > > >>>>>>>
> > > 1XhNJqjzwXvMCcAOhEH0sSXU6RTvyoSf93DHF-YMfGLk/edit?usp=sharing
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> The performance test results were already shared in the KIP
> > > > last
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>
> > > > > > > >>>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>> month.
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>>
> > > > > > > >>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> On Mon, Aug 24, 2020 at 11:10 AM Harsha Ch < harsha. ch@
> > > > gmail.
> > > > > > > com (
> > > > > > > >>>>>>> harsha.ch@gmail.com ) >
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>> wrote:
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> "Understand commitments towards driving design &
> > > > implementation of
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>
> > > > > > > >>>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>> the
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>>
> > > > > > > >>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>> KIP
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> further and how it aligns with participant interests in
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>
> > > > > > > >>>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>> contributing to
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>>
> > > > > > > >>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>> the
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> efforts (ex: in the context of Uber’s Q3/Q4 roadmap)." What
> > > > is that
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>> about?
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> On Mon, Aug 24, 2020 at 11:05 AM Kowshik Prakasam <
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>> kprakasam@ confluent. io ( kprakasam@confluent.io ) >
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> wrote:
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> Hi Harsha,
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> The following google doc contains a proposal for temporary
> > > > agenda
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>
> > > > > > > >>>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>> for
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>> the
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> KIP-405 <https://issues.apache.org/jira/browse/KIP-405> <
> > > > https:/ / issues. apache. org/ jira/ browse/ KIP-405
> > > > <https://issues.apache.org/jira/browse/KIP-405> (
> > > > > > > >>>>>>> https://issues.apache.org/jira/browse/KIP-405 ) > sync
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>
> > > > > > > >>>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>> meeting
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>>
> > > > > > > >>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> tomorrow:
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> https:/ / docs. google. com/ document/ d/ (
> > > > > > > >>>>>>> https://docs.google.com/document/d/ )
> > > > > > > >>>>>>> 1pqo8X5LU8TpwfC_iqSuVPezhfCfhGkbGN2TqiPA3LBU/edit
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> .
> > > > > > > >>>>>>> Please could you add it to the Google calendar invite?
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> Thank you.
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> Cheers,
> > > > > > > >>>>>>> Kowshik
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> On Thu, Aug 20, 2020 at 10:58 AM Harsha Ch < harsha. ch@
> > > > gmail.
> > > > > > > com (
> > > > > > > >>>>>>> harsha.ch@gmail.com ) >
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>> wrote:
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> Hi All,
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> Scheduled a meeting for Tuesday 9am - 10am. I can record
> > > and
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>
> > > > > > > >>>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>> upload for
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>>
> > > > > > > >>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> community to be able to follow the discussion.
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> Jun, please add the required folks on confluent side.
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> Thanks,
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> Harsha
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> On Thu, Aug 20, 2020 at 12:33 AM, Alexandre Dupriez <
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>> alexandre.dupriez@
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> gmail. com ( http://gmail.com/ ) > wrote:
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> Hi Jun,
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> Many thanks for your initiative.
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> If you like, I am happy to attend at the time you
> > > suggested.
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> Many thanks,
> > > > > > > >>>>>>> Alexandre
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> Le mer. 19 août 2020 à 22:00, Harsha Ch < harsha. ch@
> > > > gmail. com (
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>> harsha.
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> ch@ gmail. com ( ch@gmail.com ) ) > a écrit :
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> Hi Jun,
> > > > > > > >>>>>>> Thanks. This will help a lot. Tuesday will work for us.
> > > > > > > >>>>>>> -Harsha
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> On Wed, Aug 19, 2020 at 1:24 PM Jun Rao < jun@ confluent.
> > > > io (
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>
> > > > > > > >>>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>> jun@
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>>
> > > > > > > >>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> confluent. io ( http://confluent.io/ ) ) > wrote:
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> Hi, Satish, Ying, Harsha,
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> Do you think it would be useful to have a regular virtual
> > > > meeting
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>
> > > > > > > >>>>>
> > > > > > > >>>>
> > > > > > > >>>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>> to
> > > > > > > >>>
> > > > > > > >>>
> > > > > > > >>>>
> > > > > > > >>>>>
> > > > > > > >>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> discuss this KIP? The goal of the meeting will be sharing
> > > > > > > >>>>>>> design/development progress and discussing any open issues
> > > to
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> accelerate
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> this KIP. If so, will every Tuesday (from next week)
> > > 9am-10am
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> PT
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> work for you? I can help set up a Zoom meeting, invite
> > > > everyone who
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> might
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> be interested, have it recorded and shared, etc.
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> Thanks,
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> Jun
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> On Tue, Aug 18, 2020 at 11:01 AM Satish Duggana <
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> satish. duggana@ gmail. com ( satish. duggana@ gmail. com
> > > (
> > > > > > > >>>>>>> satish.duggana@gmail.com ) ) >
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> wrote:
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> Hi Kowshik,
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> Thanks for looking into the KIP and sending your comments.
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>>
> > > > > > > >>>>>>> 5001. Under the section "Follower fetch protocol in
> > > detail",
> > > > the
> > > > > > > >>>>>>> next-local-offset is the offset upto which the segments are
> > > > copied
> > > > > > > >>>>>>>
> > > >

Re: [DISCUSS] KIP-405: Kafka Tiered Storage

[Satish Duggana <sa...@gmail.com>]

Hi Jun,
Thanks for your comments. Please find the inline replies below.

605.2 "Build the local leader epoch cache by cutting the leader epoch
sequence received from remote storage to [LSO, ELO]." I mentioned an issue
earlier. Suppose the leader's local start offset is 100. The follower finds
a remote segment covering offset range [80, 120). The producerState with
this remote segment is up to offset 120. To trim the producerState to
offset 100 requires more work since one needs to download the previous
producerState up to offset 80 and then replay the messages from 80 to 100.
It seems that it's simpler in this case for the follower just to take the
remote segment as it is and start fetching from offset 120.

We chose that approach to avoid any edge cases here. It may be
possible that the remote log segment that is received may not have the
same leader epoch sequence from 100-120 as it contains on the
leader(this can happen due to unclean leader). It is safe to start
from what the leader returns here.Another way is to find the remote
log segment

5016. Just to echo what Kowshik was saying. It seems that
RLMM.onPartitionLeadershipChanges() is only called on the replicas for a
partition, not on the replicas for the __remote_log_segment_metadata
partition. It's not clear how the leader of __remote_log_segment_metadata
obtains the metadata for remote segments for deletion.

RLMM will always receive the callback for the remote log metadata
topic partitions hosted on the local broker and these will be
subscribed. I will make this clear in the KIP.

5100. KIP-516 has been accepted and is being implemented now. Could you
update the KIP based on topicID?

We mentioned KIP-516 and how it helps. We will update this KIP with
all the changes it brings with KIP-516.

5101. RLMM: It would be useful to clarify how the following two APIs are
used. According to the wiki, the former is used for topic deletion and the
latter is used for retention. It seems that retention should use the former
since remote segments without a matching epoch in the leader (potentially
due to unclean leader election) also need to be garbage collected. The
latter seems to be used for the new leader to determine the last tiered
segment.
    default Iterator<RemoteLogSegmentMetadata>
listRemoteLogSegments(TopicPartition topicPartition)
    Iterator<RemoteLogSegmentMetadata> listRemoteLogSegments(TopicPartition
topicPartition, long leaderEpoch);

Right,.that is what we are currently doing. We will update the
javadocs and wiki with that. Earlier, we did not want to remove the
segments which are not matched with leader epochs from the ladder
partition as they may be used later by a replica which can become a
leader (unclean leader election) and refer those segments. But that
may leak these segments in remote storage until the topic lifetime. We
decided to cleanup the segments with the oldest incase of size based
retention also.

5102. RSM:
5102.1 For methods like fetchLogSegmentData(), it seems that they can
use RemoteLogSegmentId instead of RemoteLogSegmentMetadata.

It will be useful to have metadata for RSM to fetch log segment. It
may create location/path using id with other metadata too.

5102.2 In fetchLogSegmentData(), should we use long instead of Long?

Wanted to keep endPosition as optional to read till the end of the
segment and avoid sentinels.

5102.3 Why only some of the methods have default implementation and others
Don't?

Actually,  RSM will not have any default implementations. Those 3
methods were made default earlier for tests etc. Updated the wiki.

5102.4. Could we define RemoteLogSegmentMetadataUpdate
and DeletePartitionUpdate?

Sure, they will be added.


5102.5 LogSegmentData: It seems that it's easier to pass
in leaderEpochIndex as a ByteBuffer or byte array than a file since it will
be generated in memory.

Right, this is in plan.

5102.6 RemoteLogSegmentMetadata: It seems that it needs both baseOffset and
startOffset. For example, deleteRecords() could move the startOffset to the
middle of a segment. If we copy the full segment to remote storage, the
baseOffset and the startOffset will be different.

Good point. startOffset is baseOffset by default, if not set explicitly.

5102.7 Could we define all the public methods for RemoteLogSegmentMetadata
and LogSegmentData?

Sure, updated the wiki.

5102.8 Could we document whether endOffset in RemoteLogSegmentMetadata is
inclusive/exclusive?

It is inclusive, will update.

5103. configs:
5103.1 Could we define the default value of non-required configs (e.g the
size of new thread pools)?

Sure, that makes sense.

5103.2 It seems that local.log.retention.ms should default to retention.ms,
instead of remote.log.retention.minutes. Similarly, it seems
that local.log.retention.bytes should default to segment.bytes.

Right, we do not have  remote.log.retention as we discussed earlier.
Thanks for catching the typo.

5103.3 remote.log.manager.thread.pool.size: The description says "used in
scheduling tasks to copy segments, fetch remote log indexes and clean up
remote log segments". However, there is a separate
config remote.log.reader.threads for fetching remote data. It's weird to
fetch remote index and log in different thread pools since both are used
for serving fetch requests.

Right, remote.log.manager.thread.pool is mainly used for copy/cleanup
activities. Fetch path always goes through remote.log.reader.threads.

5103.4 remote.log.manager.task.interval.ms: Is that the amount of time to
back off when there is no work to do? If so, perhaps it can be renamed as
backoff.ms.

This is the delay interval for each iteration. It may be renamed to
remote.log.manager.task.delay.ms

5103.5 Are rlm_process_interval_ms and rlm_retry_interval_ms configs? If
so, they need to be listed in this section.

remote.log.manager.task.interval.ms is the process internal, retry
interval is missing in the configs, which will be updated in the KIP.

5104. "RLM maintains a bounded cache(possibly LRU) of the index files of
remote log segments to avoid multiple index fetches from the remote
storage." Is the RLM in memory or on disk? If on disk, where is it stored?
Do we need a configuration to bound the size?

It is stored on disk. They are stored in a directory
`remote-log-index-cache` under log dir. We plan to have a config for
that instead of default. We will have a configuration for that.

5105. The KIP uses local-log-start-offset and Earliest Local Offset in
different places. It would be useful to standardize the terminology.

Sure.

5106. The section on "In BuildingRemoteLogAux state". It listed two options
without saying which option is chosen.
We already mentioned in the KIP that we chose option-2.

5107. Follower to leader transition: It has step 2, but not step 1.
Step-1 is there but it is not explicitly highlighted. It is previous
table to step-2.

5108. If a consumer fetches from the remote data and the remote storage is
not available, what error code is used in the fetch response?

Good point. We have not yet defined the error for this case. We need
to define an error message and send the same in fetch response.

5109. "ListOffsets: For timestamps >= 0, it returns the first message
offset whose timestamp is >= to the given timestamp in the request. That
means it checks in remote log time indexes first, after which local log
time indexes are checked." Could you document which method in RLMM is used
for this?

Okay.

5110. Stopreplica: "it sets all the remote log segment metadata of that
partition with a delete marker and publishes them to RLMM." This seems
outdated given the new topic deletion logic.

Will update with KIP-516 related points.

5111. "RLM follower fetches the earliest offset for the earliest leader
epoch by calling RLMM.earliestLogOffset(TopicPartition topicPartition, int
leaderEpoch) and updates that as the log start offset." Do we need that
since replication propagates logStartOffset already?

Good point. Right, existing replication protocol takes care of
updating the followers’s log start offset received from the leader.

5112. Is the default maxWaitMs of 500ms enough for fetching from remote
storage?

Remote reads may fail within the current default wait time, but
subsequent fetches would be able to serve as that data is stored in
the local cache. This cache is currently implemented in RSMs. But we
plan to pull this into the remote log messaging layer in future.

5113. "Committed offsets can be stored in a local file to avoid reading the
messages again when a broker is restarted." Could you describe the format
and the location of the file? Also, could the same message be processed by
RLMM again after broker restart? If so, how do we handle that?

Sure, we will update in the KIP.

5114. Message format
5114.1 There are two records named RemoteLogSegmentMetadataRecord with
apiKey 0 and 1.

Nice catch, that was a typo. Fixed in the wiki.

5114.2 RemoteLogSegmentMetadataRecord: Could we document whether endOffset
is inclusive/exclusive?
It is inclusive, will update.

5114.3 RemoteLogSegmentMetadataRecord: Could you explain LeaderEpoch a bit
more? Is that the epoch of the leader when it copies the segment to remote
storage? Also, how will this field be used?

Right, this is the leader epoch of the broker which copied this
segment. This is helpful in reason about which broker copied the
segment to remote storage.

5114.4 EventTimestamp: Could you explain this a bit more? Each record in
Kafka already has a timestamp field. Could we just use that?

This is the  timestamp at which  the respective event occurred. Added
this  to RemoteLogSegmentMetadata as RLMM can be  any other
implementation. We thought about that but it looked cleaner to use at
the message structure level instead of getting that from the consumer
record and using that to build the respective event.


5114.5 SegmentSizeInBytes: Could this just be int32?

Right, it looks like config allows only int value >= 14.

5115. RemoteLogCleaner(RLC): This could be confused with the log cleaner
for compaction. Perhaps it can be renamed to sth like
RemotePartitionRemover.

I am fine with RemotePartitionRemover or RemoteLogDeletionManager(we
have other manager classes like RLM, RLMM).

5116. "RLC receives the delete_partition_marked and processes it if it is
not yet processed earlier." How does it know whether
delete_partition_marked has been processed earlier?

This is to handle duplicate delete_partition_marked events. RLC
internally maintains a state for the delete_partition events and if it
already has an existing event then it ignores if it is already being
processed.

5117. Should we add a new MessageFormatter to read the tier metadata topic?

Right, this is in plan but did not mention it in the KIP. This will be
useful for debugging purposes too.

5118. "Maximum remote log reader thread pool task queue size. If the task
queue is full, broker will stop reading remote log segments." What do we
return to the fetch request in this case?

We return an error response for that partition.

5119. It would be useful to list all things not supported in the first
version in a Future work or Limitations section. For example, compacted
topic, JBOD, changing remote.log.storage.enable from true to false, etc.

We already have a non-goals section which is filled with some of these
details. Do we need another limitations section?

Thanks,
Satish.

On Wed, Nov 4, 2020 at 11:27 PM Jun Rao <ju...@confluent.io> wrote:
>
> Hi, Satish,
>
> Thanks for the updated KIP. A few more comments below.
>
> 605.2 "Build the local leader epoch cache by cutting the leader epoch
> sequence received from remote storage to [LSO, ELO]." I mentioned an issue
> earlier. Suppose the leader's local start offset is 100. The follower finds
> a remote segment covering offset range [80, 120). The producerState with
> this remote segment is up to offset 120. To trim the producerState to
> offset 100 requires more work since one needs to download the previous
> producerState up to offset 80 and then replay the messages from 80 to 100.
> It seems that it's simpler in this case for the follower just to take the
> remote segment as it is and start fetching from offset 120.
>
> 5016. Just to echo what Kowshik was saying. It seems that
> RLMM.onPartitionLeadershipChanges() is only called on the replicas for a
> partition, not on the replicas for the __remote_log_segment_metadata
> partition. It's not clear how the leader of __remote_log_segment_metadata
> obtains the metadata for remote segments for deletion.
>
> 5100. KIP-516 has been accepted and is being implemented now. Could you
> update the KIP based on topicID?
>
> 5101. RLMM: It would be useful to clarify how the following two APIs are
> used. According to the wiki, the former is used for topic deletion and the
> latter is used for retention. It seems that retention should use the former
> since remote segments without a matching epoch in the leader (potentially
> due to unclean leader election) also need to be garbage collected. The
> latter seems to be used for the new leader to determine the last tiered
> segment.
>     default Iterator<RemoteLogSegmentMetadata>
> listRemoteLogSegments(TopicPartition topicPartition)
>     Iterator<RemoteLogSegmentMetadata> listRemoteLogSegments(TopicPartition
> topicPartition, long leaderEpoch);
>
> 5102. RSM:
> 5102.1 For methods like fetchLogSegmentData(), it seems that they can
> use RemoteLogSegmentId instead of RemoteLogSegmentMetadata.
> 5102.2 In fetchLogSegmentData(), should we use long instead of Long?
> 5102.3 Why only some of the methods have default implementation and others
> don't?
> 5102.4. Could we define RemoteLogSegmentMetadataUpdate
> and DeletePartitionUpdate?
> 5102.5 LogSegmentData: It seems that it's easier to pass
> in leaderEpochIndex as a ByteBuffer or byte array than a file since it will
> be generated in memory.
> 5102.6 RemoteLogSegmentMetadata: It seems that it needs both baseOffset and
> startOffset. For example, deleteRecords() could move the startOffset to the
> middle of a segment. If we copy the full segment to remote storage, the
> baseOffset and the startOffset will be different.
> 5102.7 Could we define all the public methods for RemoteLogSegmentMetadata
> and LogSegmentData?
> 5102.8 Could we document whether endOffset in RemoteLogSegmentMetadata is
> inclusive/exclusive?
>
> 5103. configs:
> 5103.1 Could we define the default value of non-required configs (e.g the
> size of new thread pools)?
> 5103.2 It seems that local.log.retention.ms should default to retention.ms,
> instead of remote.log.retention.minutes. Similarly, it seems
> that local.log.retention.bytes should default to segment.bytes.
> 5103.3 remote.log.manager.thread.pool.size: The description says "used in
> scheduling tasks to copy segments, fetch remote log indexes and clean up
> remote log segments". However, there is a separate
> config remote.log.reader.threads for fetching remote data. It's weird to
> fetch remote index and log in different thread pools since both are used
> for serving fetch requests.
> 5103.4 remote.log.manager.task.interval.ms: Is that the amount of time to
> back off when there is no work to do? If so, perhaps it can be renamed as
> backoff.ms.
> 5103.5 Are rlm_process_interval_ms and rlm_retry_interval_ms configs? If
> so, they need to be listed in this section.
>
> 5104. "RLM maintains a bounded cache(possibly LRU) of the index files of
> remote log segments to avoid multiple index fetches from the remote
> storage." Is the RLM in memory or on disk? If on disk, where is it stored?
> Do we need a configuration to bound the size?
>
> 5105. The KIP uses local-log-start-offset and Earliest Local Offset in
> different places. It would be useful to standardize the terminology.
>
> 5106. The section on "In BuildingRemoteLogAux state". It listed two options
> without saying which option is chosen.
>
> 5107. Follower to leader transition: It has step 2, but not step 1.
>
> 5108. If a consumer fetches from the remote data and the remote storage is
> not available, what error code is used in the fetch response?
>
> 5109. "ListOffsets: For timestamps >= 0, it returns the first message
> offset whose timestamp is >= to the given timestamp in the request. That
> means it checks in remote log time indexes first, after which local log
> time indexes are checked." Could you document which method in RLMM is used
> for this?
>
> 5110. Stopreplica: "it sets all the remote log segment metadata of that
> partition with a delete marker and publishes them to RLMM." This seems
> outdated given the new topic deletion logic.
>
> 5111. "RLM follower fetches the earliest offset for the earliest leader
> epoch by calling RLMM.earliestLogOffset(TopicPartition topicPartition, int
> leaderEpoch) and updates that as the log start offset." Do we need that
> since replication propagates logStartOffset already?
>
> 5112. Is the default maxWaitMs of 500ms enough for fetching from remote
> storage?
>
> 5113. "Committed offsets can be stored in a local file to avoid reading the
> messages again when a broker is restarted." Could you describe the format
> and the location of the file? Also, could the same message be processed by
> RLMM again after broker restart? If so, how do we handle that?
>
> 5114. Message format
> 5114.1 There are two records named RemoteLogSegmentMetadataRecord with
> apiKey 0 and 1.
> 5114.2 RemoteLogSegmentMetadataRecord: Could we document whether endOffset
> is inclusive/exclusive?
> 5114.3 RemoteLogSegmentMetadataRecord: Could you explain LeaderEpoch a bit
> more? Is that the epoch of the leader when it copies the segment to remote
> storage? Also, how will this field be used?
> 5114.4 EventTimestamp: Could you explain this a bit more? Each record in
> Kafka already has a timestamp field. Could we just use that?
> 5114.5 SegmentSizeInBytes: Could this just be int32?
>
> 5115. RemoteLogCleaner(RLC): This could be confused with the log cleaner
> for compaction. Perhaps it can be renamed to sth like
> RemotePartitionRemover.
>
> 5116. "RLC receives the delete_partition_marked and processes it if it is
> not yet processed earlier." How does it know whether
> delete_partition_marked has been processed earlier?
>
> 5117. Should we add a new MessageFormatter to read the tier metadata topic?
>
> 5118. "Maximum remote log reader thread pool task queue size. If the task
> queue is full, broker will stop reading remote log segments." What do we
> return to the fetch request in this case?
>
> 5119. It would be useful to list all things not supported in the first
> version in a Future work or Limitations section. For example, compacted
> topic, JBOD, changing remote.log.storage.enable from true to false, etc.
>
> Thanks,
>
> Jun
>
> On Tue, Oct 27, 2020 at 5:57 PM Kowshik Prakasam <kp...@confluent.io>
> wrote:
>
> > Hi Satish,
> >
> > Thanks for the updates to the KIP. Here are my first batch of
> > comments/suggestions on the latest version of the KIP.
> >
> > 5012. In the RemoteStorageManager interface, there is an API defined for
> > each file type. For example, fetchOffsetIndex, fetchTimestampIndex etc. To
> > avoid the duplication, I'd suggest we can instead have a FileType enum and
> > a common get API based on the FileType.
> >
> > 5013. There are some references to the Google doc in the KIP. I wasn't sure
> > if the Google doc is expected to be in sync with the contents of the wiki.
> > Going forward, it seems easier if just the KIP is maintained as the source
> > of truth. In this regard, could you please move all the references to the
> > Google doc, maybe to a separate References section at the bottom of the
> > KIP?
> >
> > 5014. There are some TODO sections in the KIP. Would these be filled up in
> > future iterations?
> >
> > 5015. Under "Topic deletion lifecycle", I'm trying to understand why do we
> > need delete_partition_marked as well as the delete_partition_started
> > messages. I couldn't spot a drawback if supposing we simplified the design
> > such that the controller would only write delete_partition_started message,
> > and RemoteLogCleaner (RLC) instance picks it up for processing. What am I
> > missing?
> >
> > 5016. Under "Topic deletion lifecycle", step (4) is mentioned as "RLC gets
> > all the remote log segments for the partition and each of these remote log
> > segments is deleted with the next steps.". Since the RLC instance runs on
> > each tier topic partition leader, how does the RLC then get the list of
> > remote log segments to be deleted? It will be useful to add that detail to
> > the KIP.
> >
> > 5017. Under "Public Interfaces -> Configs", there is a line mentioning "We
> > will support flipping remote.log.storage.enable in next versions." It will
> > be useful to mention this in the "Future Work" section of the KIP too.
> >
> > 5018. The KIP introduces a number of configuration parameters. It will be
> > useful to mention in the KIP if the user should assume these as static
> > configuration in the server.properties file, or dynamic configuration which
> > can be modified without restarting the broker.
> >
> > 5019.  Maybe this is planned as a future update to the KIP, but I thought
> > I'd mention it here. Could you please add details to the KIP on why RocksDB
> > was chosen as the default cache implementation of RLMM, and how it is going
> > to be used? Were alternatives compared/considered? For example, it would be
> > useful to explain/evaluate the following: 1) debuggability of the RocksDB
> > JNI interface, 2) performance, 3) portability across platforms and 4)
> > interface parity of RocksDB’s JNI api with it's underlying C/C++ api.
> >
> > 5020. Following up on (5019), for the RocksDB cache, it will be useful to
> > explain the relationship/mapping between the following in the KIP: 1) # of
> > tiered partitions, 2) # of partitions of metadata topic
> > __remote_log_metadata and 3) # of RocksDB instances. i.e. is the plan to
> > have a RocksDB instance per tiered partition, or per metadata topic
> > partition, or just 1 for per broker?
> >
> > 5021. I was looking at the implementation prototype (PR link:
> > https://github.com/apache/kafka/pull/7561). It seems that a boolean
> > attribute is being introduced into the Log layer to check if remote log
> > capability is enabled. While the boolean footprint is small at the moment,
> > this can easily grow in the future and become harder to
> > test/maintain, considering that the Log layer is already pretty complex. We
> > should start thinking about how to manage such changes to the Log layer
> > (for the purpose of improved testability, better separation of concerns and
> > readability). One proposal I have is to take a step back and define a
> > higher level Log interface. Then, the Broker code can be changed to use
> > this interface. It can be changed such that only a handle to the interface
> > is exposed to other components (such as LogCleaner, ReplicaManager etc.)
> > and not the underlying Log object. This approach keeps the user of the Log
> > layer agnostic of the whereabouts of the data. Underneath the interface,
> > the implementing classes can completely separate local log capabilities
> > from the remote log. For example, the Log class can be simplified to only
> > manage logic surrounding local log segments and metadata. Additionally, a
> > wrapper class can be provided (implementing the higher level Log interface)
> > which will contain any/all logic surrounding tiered data. The wrapper
> > class will wrap around an instance of the Log class delegating the local
> > log logic to it. Finally, a handle to the wrapper class can be exposed to
> > the other components wherever they need a handle to the higher level Log
> > interface.
> >
> >
> > Cheers,
> > Kowshik
> >
> > On Mon, Oct 26, 2020 at 9:52 PM Satish Duggana <sa...@gmail.com>
> > wrote:
> >
> > > Hi,
> > > KIP is updated with 1) topic deletion lifecycle and its related items
> > > 2) Protocol changes(mainly related to ListOffsets) and other minor
> > > changes.
> > > Please go through them and let us know your comments.
> > >
> > > Thanks,
> > > Satish.
> > >
> > > On Mon, Sep 28, 2020 at 9:10 PM Satish Duggana <satish.duggana@gmail.com
> > >
> > > wrote:
> > > >
> > > > Hi Dhruvil,
> > > > Thanks for looking into the KIP and sending your comments. Sorry for
> > > > the late reply, missed it in the mail thread.
> > > >
> > > > 1. Could you describe how retention would work with this KIP and which
> > > > threads are responsible for driving this work? I believe there are 3
> > > kinds
> > > > of retention processes we are looking at:
> > > >   (a) Regular retention for data in tiered storage as per configured `
> > > > retention.ms` / `retention.bytes`.
> > > >   (b) Local retention for data in local storage as per configured `
> > > > local.log.retention.ms` / `local.log.retention.bytes`
> > > >   (c) Possibly regular retention for data in local storage, if the
> > > tiering
> > > > task is lagging or for data that is below the log start offset.
> > > >
> > > > Local log retention is done by the existing log cleanup tasks. These
> > > > are not done for segments that are not yet copied to remote storage.
> > > > Remote log cleanup is done by the leader partition’s RLMTask.
> > > >
> > > > 2. When does a segment become eligible to be tiered? Is it as soon as
> > the
> > > > segment is rolled and the end offset is less than the last stable
> > offset
> > > as
> > > > mentioned in the KIP? I wonder if we need to consider other parameters
> > > too,
> > > > like the highwatermark so that we are guaranteed that what we are
> > tiering
> > > > has been committed to the log and accepted by the ISR.
> > > >
> > > > AFAIK, last stable offset is always <= highwatermark. This will make
> > > > sure we are always tiering the message segments which have been
> > > > accepted by ISR and transactionally completed.
> > > >
> > > >
> > > > 3. The section on "Follower Fetch Scenarios" is useful but is a bit
> > > > difficult to parse at the moment. It would be useful to summarize the
> > > > changes we need in the ReplicaFetcher.
> > > >
> > > > It may become difficult for users to read/follow if we add code changes
> > > here.
> > > >
> > > > 4. Related to the above, it's a bit unclear how we are planning on
> > > > restoring the producer state for a new replica. Could you expand on
> > that?
> > > >
> > > > It is mentioned in the KIP BuildingRemoteLogAuxState is introduced to
> > > > build the state like leader epoch sequence and producer snapshots
> > > > before it starts fetching the data from the leader. We will make it
> > > > clear in the KIP.
> > > >
> > > >
> > > > 5. Similarly, it would be worth summarizing the behavior on unclean
> > > leader
> > > > election. There are several scenarios to consider here: data loss from
> > > > local log, data loss from remote log, data loss from metadata topic,
> > etc.
> > > > It's worth describing these in detail.
> > > >
> > > > We mentioned the cases about unclean leader election in the follower
> > > > fetch scenarios.
> > > > If there are errors while fetching data from remote store or metadata
> > > > store, it will work the same way as it works with local log. It
> > > > returns the error back to the caller. Please let us know if I am
> > > > missing your point here.
> > > >
> > > >
> > > > 7. For a READ_COMMITTED FetchRequest, how do we retrieve and return the
> > > > aborted transaction metadata?
> > > >
> > > > When a fetch for a remote log is accessed, we will fetch aborted
> > > > transactions along with the segment if it is not found in the local
> > > > index cache. This includes the case of transaction index not existing
> > > > in the remote log segment. That means, the cache entry can be empty or
> > > > have a list of aborted transactions.
> > > >
> > > >
> > > > 8. The `LogSegmentData` class assumes that we have a log segment,
> > offset
> > > > index, time index, transaction index, producer snapshot and leader
> > epoch
> > > > index. How do we deal with cases where we do not have one or more of
> > > these?
> > > > For example, we may not have a transaction index or producer snapshot
> > > for a
> > > > particular segment. The former is optional, and the latter is only kept
> > > for
> > > > up to the 3 latest segments.
> > > >
> > > > This is a good point,  we discussed this in the last meeting.
> > > > Transaction index is optional and we will copy them only if it exists.
> > > > We want to keep all the producer snapshots at each log segment rolling
> > > > and they can be removed if the log copying is successful and it still
> > > > maintains the existing latest 3 segments, We only delete the producer
> > > > snapshots which have been copied to remote log segments on leader.
> > > > Follower will keep the log segments beyond the segments which have not
> > > > been copied to remote storage. We will update the KIP with these
> > > > details.
> > > >
> > > > Thanks,
> > > > Satish.
> > > >
> > > > On Thu, Sep 17, 2020 at 1:47 AM Dhruvil Shah <dh...@confluent.io>
> > > wrote:
> > > > >
> > > > > Hi Satish, Harsha,
> > > > >
> > > > > Thanks for the KIP. Few questions below:
> > > > >
> > > > > 1. Could you describe how retention would work with this KIP and
> > which
> > > > > threads are responsible for driving this work? I believe there are 3
> > > kinds
> > > > > of retention processes we are looking at:
> > > > >   (a) Regular retention for data in tiered storage as per configured
> > `
> > > > > retention.ms` / `retention.bytes`.
> > > > >   (b) Local retention for data in local storage as per configured `
> > > > > local.log.retention.ms` / `local.log.retention.bytes`
> > > > >   (c) Possibly regular retention for data in local storage, if the
> > > tiering
> > > > > task is lagging or for data that is below the log start offset.
> > > > >
> > > > > 2. When does a segment become eligible to be tiered? Is it as soon as
> > > the
> > > > > segment is rolled and the end offset is less than the last stable
> > > offset as
> > > > > mentioned in the KIP? I wonder if we need to consider other
> > parameters
> > > too,
> > > > > like the highwatermark so that we are guaranteed that what we are
> > > tiering
> > > > > has been committed to the log and accepted by the ISR.
> > > > >
> > > > > 3. The section on "Follower Fetch Scenarios" is useful but is a bit
> > > > > difficult to parse at the moment. It would be useful to summarize the
> > > > > changes we need in the ReplicaFetcher.
> > > > >
> > > > > 4. Related to the above, it's a bit unclear how we are planning on
> > > > > restoring the producer state for a new replica. Could you expand on
> > > that?
> > > > >
> > > > > 5. Similarly, it would be worth summarizing the behavior on unclean
> > > leader
> > > > > election. There are several scenarios to consider here: data loss
> > from
> > > > > local log, data loss from remote log, data loss from metadata topic,
> > > etc.
> > > > > It's worth describing these in detail.
> > > > >
> > > > > 6. It would be useful to add details about how we plan on using
> > > RocksDB in
> > > > > the default implementation of `RemoteLogMetadataManager`.
> > > > >
> > > > > 7. For a READ_COMMITTED FetchRequest, how do we retrieve and return
> > the
> > > > > aborted transaction metadata?
> > > > >
> > > > > 8. The `LogSegmentData` class assumes that we have a log segment,
> > > offset
> > > > > index, time index, transaction index, producer snapshot and leader
> > > epoch
> > > > > index. How do we deal with cases where we do not have one or more of
> > > these?
> > > > > For example, we may not have a transaction index or producer snapshot
> > > for a
> > > > > particular segment. The former is optional, and the latter is only
> > > kept for
> > > > > up to the 3 latest segments.
> > > > >
> > > > > Thanks,
> > > > > Dhruvil
> > > > >
> > > > > On Mon, Sep 7, 2020 at 6:54 PM Harsha Ch <ha...@gmail.com>
> > wrote:
> > > > >
> > > > > > Hi All,
> > > > > >
> > > > > > We are all working through the last meeting feedback. I'll cancel
> > the
> > > > > > tomorrow 's meeting and we can meanwhile continue our discussion in
> > > mailing
> > > > > > list. We can start the regular meeting from next week onwards.
> > > > > >
> > > > > > Thanks,
> > > > > >
> > > > > > Harsha
> > > > > >
> > > > > > On Fri, Sep 04, 2020 at 8:41 AM, Satish Duggana <
> > > satish.duggana@gmail.com
> > > > > > > wrote:
> > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > Hi Jun,
> > > > > > > Thanks for your thorough review and comments. Please find the
> > > inline
> > > > > > > replies below.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > 600. The topic deletion logic needs more details.
> > > > > > > 600.1 The KIP mentions "The controller considers the topic
> > > partition is
> > > > > > > deleted only when it determines that there are no log segments
> > for
> > > that
> > > > > > > topic partition by using RLMM". How is this done?
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > It uses RLMM#listSegments() returns all the segments for the
> > given
> > > topic
> > > > > > > partition.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > 600.2 "If the delete option is enabled then the leader will stop
> > > RLM task
> > > > > > > and stop processing and it sets all the remote log segment
> > > metadata of
> > > > > > > that partition with a delete marker and publishes them to RLMM."
> > We
> > > > > > > discussed this earlier. When a topic is being deleted, there may
> > > not be a
> > > > > > > leader for the deleted partition.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > This is a good point. As suggested in the meeting, we will add a
> > > separate
> > > > > > > section for topic/partition deletion lifecycle and this scenario
> > > will be
> > > > > > > addressed.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > 601. Unclean leader election
> > > > > > > 601.1 Scenario 1: new empty follower
> > > > > > > After step 1, the follower restores up to offset 3. So why does
> > it
> > > have
> > > > > > > LE-2 <https://issues.apache.org/jira/browse/LE-2> at offset 5?
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > Nice catch. It was showing the leader epoch fetched from the
> > remote
> > > > > > > storage. It should be shown with the truncated till offset 3.
> > > Updated the
> > > > > > > KIP.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > 601.2 senario 5: After Step 3, leader A has inconsistent data
> > > between its
> > > > > > > local and the tiered data. For example. offset 3 has msg 3 LE-0
> > > <https://issues.apache.org/jira/browse/LE-0> locally,
> > > > > > > but msg 5 LE-1 <https://issues.apache.org/jira/browse/LE-1> in
> > > the remote store. While it's ok for the unclean leader
> > > > > > > to lose data, it should still return consistent data, whether
> > it's
> > > from
> > > > > > > the local or the remote store.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > There is no inconsistency here as LE-0
> > > <https://issues.apache.org/jira/browse/LE-0> offsets are [0, 4] and LE-2
> > > <https://issues.apache.org/jira/browse/LE-2>:
> > > > > > > [5, ]. It will always get the right records for the given offset
> > > and
> > > > > > > leader epoch. In case of remote, RSM is invoked to get the remote
> > > log
> > > > > > > segment that contains the given offset with the leader epoch.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > 601.4 It seems that retention is based on
> > > > > > > listRemoteLogSegments(TopicPartition topicPartition, long
> > > leaderEpoch).
> > > > > > > When there is an unclean leader election, it's possible for the
> > new
> > > > > > leader
> > > > > > > to not to include certain epochs in its epoch cache. How are
> > remote
> > > > > > > segments associated with those epochs being cleaned?
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > That is a good point. This leader will also cleanup the epochs
> > > earlier to
> > > > > > > its start leader epoch and delete those segments. It gets the
> > > earliest
> > > > > > > epoch for a partition and starts deleting segments from that
> > leader
> > > > > > epoch.
> > > > > > > We need one more API in RLMM to get the earliest leader epoch.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > 601.5 The KIP discusses the handling of unclean leader elections
> > > for user
> > > > > > > topics. What about unclean leader elections on
> > > > > > > __remote_log_segment_metadata?
> > > > > > > This is the same as other system topics like consumer_offsets,
> > > > > > > __transaction_state topics. As discussed in the meeting, we will
> > > add the
> > > > > > > behavior of __remote_log_segment_metadata topic’s unclean leader
> > > > > > > truncation.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > 602. It would be useful to clarify the limitations in the initial
> > > > > > release.
> > > > > > > The KIP mentions not supporting compacted topics. What about JBOD
> > > and
> > > > > > > changing the configuration of a topic from delete to compact
> > after
> > > > > > remote.
> > > > > > > log. storage. enable ( http://remote.log.storage.enable/ ) is
> > > enabled?
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > This was updated in the KIP earlier.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > 603. RLM leader tasks:
> > > > > > > 603.1"It checks for rolled over LogSegments (which have the last
> > > message
> > > > > > > offset less than last stable offset of that topic partition) and
> > > copies
> > > > > > > them along with their offset/time/transaction indexes and leader
> > > epoch
> > > > > > > cache to the remote tier." It needs to copy the producer snapshot
> > > too.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > Right. It copies producer snapshots too as mentioned in
> > > LogSegmentData.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > 603.2 "Local logs are not cleaned up till those segments are
> > copied
> > > > > > > successfully to remote even though their retention time/size is
> > > reached"
> > > > > > > This seems weird. If the tiering stops because the remote store
> > is
> > > not
> > > > > > > available, we don't want the local data to grow forever.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > It was clarified in the discussion that the comment was more
> > about
> > > the
> > > > > > > local storage goes beyond the log.retention. The above statement
> > > is about
> > > > > > > local.log.retention but not for the complete log.retention. When
> > it
> > > > > > > reaches the log.retention then it will delete the local logs even
> > > though
> > > > > > > those are not copied to remote storage.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > 604. "RLM maintains a bounded cache(possibly LRU) of the index
> > > files of
> > > > > > > remote log segments to avoid multiple index fetches from the
> > remote
> > > > > > > storage. These indexes can be used in the same way as local
> > segment
> > > > > > > indexes are used." Could you provide more details on this? Are
> > the
> > > > > > indexes
> > > > > > > cached in memory or on disk? If on disk, where are they stored?
> > > Are the
> > > > > > > cached indexes bound by a certain size?
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > These are cached on disk and stored in log.dir with a name
> > > > > > > “__remote_log_index_cache”. They are bound by the total size.
> > This
> > > will
> > > > > > be
> > > > > > > exposed as a user configuration,
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > 605. BuildingRemoteLogAux
> > > > > > > 605.1 In this section, two options are listed. Which one is
> > chosen?
> > > > > > > Option-2, updated the KIP.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > 605.2 In option 2, it says "Build the local leader epoch cache by
> > > cutting
> > > > > > > the leader epoch sequence received from remote storage to [LSO,
> > > ELO].
> > > > > > (LSO
> > > > > > >
> > > > > > > = log start offset)." We need to do the same thing for the
> > producer
> > > > > > > snapshot. However, it's hard to cut the producer snapshot to an
> > > earlier
> > > > > > > offset. Another option is to simply take the lastOffset from the
> > > remote
> > > > > > > segment and use that as the starting fetch offset in the
> > follower.
> > > This
> > > > > > > avoids the need for cutting.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > Right, this was mentioned in the “transactional support” section
> > > about
> > > > > > > adding these details.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > 606. ListOffsets: Since we need a version bump, could you
> > document
> > > it
> > > > > > > under a protocol change section?
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > Sure, we will update the KIP.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > 607. "LogStartOffset of a topic can point to either of local
> > > segment or
> > > > > > > remote segment but it is initialised and maintained in the Log
> > > class like
> > > > > > > now. This is already maintained in `Log` class while loading the
> > > logs and
> > > > > > > it can also be fetched from RemoteLogMetadataManager." What will
> > > happen
> > > > > > to
> > > > > > > the existing logic (e.g. log recovery) that currently depends on
> > > > > > > logStartOffset but assumes it's local?
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > They use a field called localLogStartOffset which is the local
> > log
> > > start
> > > > > > > offset..
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > 608. Handle expired remote segment: How does it pick up new
> > > > > > logStartOffset
> > > > > > > from deleteRecords?
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > Good point. This was not addressed in the KIP. Will update the
> > KIP
> > > on how
> > > > > > > the RLM task handles this scenario.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > 609. RLMM message format:
> > > > > > > 609.1 It includes both MaxTimestamp and EventTimestamp. Where
> > does
> > > it get
> > > > > > > both since the message in the log only contains one timestamp?
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > `EventTimeStamp` is the timestamp at which that segment metadata
> > > event is
> > > > > > > generated. This is more for audits.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > 609.2 If we change just the state (e.g. to DELETE_STARTED), it
> > > seems it's
> > > > > > > wasteful to have to include all other fields not changed.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > This is a good point. We thought about incremental updates. But
> > we
> > > want
> > > > > > to
> > > > > > > make sure all the events are in the expected order and take
> > action
> > > based
> > > > > > > on the latest event. Will think through the approaches in detail
> > > and
> > > > > > > update here.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > 609.3 Could you document which process makes the following
> > > transitions
> > > > > > > DELETE_MARKED, DELETE_STARTED, DELETE_FINISHED?
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > Okay, will document more details.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > 610. remote.log.reader.max.pending.tasks: "Maximum remote log
> > > reader
> > > > > > > thread pool task queue size. If the task queue is full, broker
> > > will stop
> > > > > > > reading remote log segments." What does the broker do if the
> > queue
> > > is
> > > > > > > full?
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > It returns an error for this topic partition.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > 611. What do we return if the request offset/epoch doesn't exist
> > > in the
> > > > > > > following API?
> > > > > > > RemoteLogSegmentMetadata remoteLogSegmentMetadata(TopicPartition
> > > > > > > topicPartition, long offset, int epochForOffset)
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > This returns null. But we prefer to update the return type as
> > > Optional
> > > > > > and
> > > > > > > return Empty if that does not exist.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > Thanks,
> > > > > > > Satish.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > On Tue, Sep 1, 2020 at 9:45 AM Jun Rao < jun@ confluent. io (
> > > > > > > jun@confluent.io ) > wrote:
> > > > > > >
> > > > > > >
> > > > > > >>
> > > > > > >>
> > > > > > >> Hi, Satish,
> > > > > > >>
> > > > > > >>
> > > > > > >>
> > > > > > >> Thanks for the updated KIP. Made another pass. A few more
> > comments
> > > > > > below.
> > > > > > >>
> > > > > > >>
> > > > > > >>
> > > > > > >> 600. The topic deletion logic needs more details.
> > > > > > >> 600.1 The KIP mentions "The controller considers the topic
> > > partition is
> > > > > > >> deleted only when it determines that there are no log segments
> > > for that
> > > > > > >> topic partition by using RLMM". How is this done? 600.2 "If the
> > > delete
> > > > > > >> option is enabled then the leader will stop RLM task and stop
> > > processing
> > > > > > >> and it sets all the remote log segment metadata of that
> > partition
> > > with a
> > > > > > >> delete marker and publishes them to RLMM." We discussed this
> > > earlier.
> > > > > > When
> > > > > > >> a topic is being deleted, there may not be a leader for the
> > > deleted
> > > > > > >> partition.
> > > > > > >>
> > > > > > >>
> > > > > > >>
> > > > > > >> 601. Unclean leader election
> > > > > > >> 601.1 Scenario 1: new empty follower
> > > > > > >> After step 1, the follower restores up to offset 3. So why does
> > > it have
> > > > > > >> LE-2 <https://issues.apache.org/jira/browse/LE-2> at offset 5?
> > > > > > >> 601.2 senario 5: After Step 3, leader A has inconsistent data
> > > between
> > > > > > its
> > > > > > >> local and the tiered data. For example. offset 3 has msg 3 LE-0
> > > <https://issues.apache.org/jira/browse/LE-0> locally,
> > > > > > >> but msg 5 LE-1 <https://issues.apache.org/jira/browse/LE-1> in
> > > the remote store. While it's ok for the unclean leader
> > > > > > >> to lose data, it should still return consistent data, whether
> > > it's from
> > > > > > >> the local or the remote store.
> > > > > > >> 601.3 The follower picks up log start offset using the following
> > > api.
> > > > > > >> Suppose that we have 3 remote segments (LE, SegmentStartOffset)
> > > as (2,
> > > > > > >> 10),
> > > > > > >> (3, 20) and (7, 15) due to an unclean leader election. Using the
> > > > > > following
> > > > > > >> api will cause logStartOffset to go backward from 20 to 15. How
> > > do we
> > > > > > >> prevent that?
> > > > > > >> earliestLogOffset(TopicPartition topicPartition, int
> > leaderEpoch)
> > > 601.4
> > > > > > It
> > > > > > >> seems that retention is based on
> > > > > > >> listRemoteLogSegments(TopicPartition topicPartition, long
> > > leaderEpoch).
> > > > > > >> When there is an unclean leader election, it's possible for the
> > > new
> > > > > > leader
> > > > > > >> to not to include certain epochs in its epoch cache. How are
> > > remote
> > > > > > >> segments associated with those epochs being cleaned? 601.5 The
> > KIP
> > > > > > >> discusses the handling of unclean leader elections for user
> > > topics. What
> > > > > > >> about unclean leader elections on
> > > > > > >> __remote_log_segment_metadata?
> > > > > > >>
> > > > > > >>
> > > > > > >>
> > > > > > >> 602. It would be useful to clarify the limitations in the
> > initial
> > > > > > release.
> > > > > > >> The KIP mentions not supporting compacted topics. What about
> > JBOD
> > > and
> > > > > > >> changing the configuration of a topic from delete to compact
> > after
> > > > > > remote.
> > > > > > >> log. storage. enable ( http://remote.log.storage.enable/ ) is
> > > enabled?
> > > > > > >>
> > > > > > >>
> > > > > > >>
> > > > > > >> 603. RLM leader tasks:
> > > > > > >> 603.1"It checks for rolled over LogSegments (which have the last
> > > message
> > > > > > >> offset less than last stable offset of that topic partition) and
> > > copies
> > > > > > >> them along with their offset/time/transaction indexes and leader
> > > epoch
> > > > > > >> cache to the remote tier." It needs to copy the producer
> > snapshot
> > > too.
> > > > > > >> 603.2 "Local logs are not cleaned up till those segments are
> > > copied
> > > > > > >> successfully to remote even though their retention time/size is
> > > reached"
> > > > > > >> This seems weird. If the tiering stops because the remote store
> > > is not
> > > > > > >> available, we don't want the local data to grow forever.
> > > > > > >>
> > > > > > >>
> > > > > > >>
> > > > > > >> 604. "RLM maintains a bounded cache(possibly LRU) of the index
> > > files of
> > > > > > >> remote log segments to avoid multiple index fetches from the
> > > remote
> > > > > > >> storage. These indexes can be used in the same way as local
> > > segment
> > > > > > >> indexes are used." Could you provide more details on this? Are
> > the
> > > > > > indexes
> > > > > > >> cached in memory or on disk? If on disk, where are they stored?
> > > Are the
> > > > > > >> cached indexes bound by a certain size?
> > > > > > >>
> > > > > > >>
> > > > > > >>
> > > > > > >> 605. BuildingRemoteLogAux
> > > > > > >> 605.1 In this section, two options are listed. Which one is
> > > chosen?
> > > > > > 605.2
> > > > > > >> In option 2, it says "Build the local leader epoch cache by
> > > cutting the
> > > > > > >> leader epoch sequence received from remote storage to [LSO,
> > ELO].
> > > (LSO
> > > > > > >> = log start offset)." We need to do the same thing for the
> > > producer
> > > > > > >> snapshot. However, it's hard to cut the producer snapshot to an
> > > earlier
> > > > > > >> offset. Another option is to simply take the lastOffset from the
> > > remote
> > > > > > >> segment and use that as the starting fetch offset in the
> > > follower. This
> > > > > > >> avoids the need for cutting.
> > > > > > >>
> > > > > > >>
> > > > > > >>
> > > > > > >> 606. ListOffsets: Since we need a version bump, could you
> > > document it
> > > > > > >> under a protocol change section?
> > > > > > >>
> > > > > > >>
> > > > > > >>
> > > > > > >> 607. "LogStartOffset of a topic can point to either of local
> > > segment or
> > > > > > >> remote segment but it is initialised and maintained in the Log
> > > class
> > > > > > like
> > > > > > >> now. This is already maintained in `Log` class while loading the
> > > logs
> > > > > > and
> > > > > > >> it can also be fetched from RemoteLogMetadataManager." What will
> > > happen
> > > > > > to
> > > > > > >> the existing logic (e.g. log recovery) that currently depends on
> > > > > > >> logStartOffset but assumes it's local?
> > > > > > >>
> > > > > > >>
> > > > > > >>
> > > > > > >> 608. Handle expired remote segment: How does it pick up new
> > > > > > logStartOffset
> > > > > > >> from deleteRecords?
> > > > > > >>
> > > > > > >>
> > > > > > >>
> > > > > > >> 609. RLMM message format:
> > > > > > >> 609.1 It includes both MaxTimestamp and EventTimestamp. Where
> > > does it
> > > > > > get
> > > > > > >> both since the message in the log only contains one timestamp?
> > > 609.2 If
> > > > > > we
> > > > > > >> change just the state (e.g. to DELETE_STARTED), it seems it's
> > > wasteful
> > > > > > to
> > > > > > >> have to include all other fields not changed. 609.3 Could you
> > > document
> > > > > > >> which process makes the following transitions DELETE_MARKED,
> > > > > > >> DELETE_STARTED, DELETE_FINISHED?
> > > > > > >>
> > > > > > >>
> > > > > > >>
> > > > > > >> 610. remote.log.reader.max.pending.tasks: "Maximum remote log
> > > reader
> > > > > > >> thread pool task queue size. If the task queue is full, broker
> > > will stop
> > > > > > >> reading remote log segments." What does the broker do if the
> > > queue is
> > > > > > >> full?
> > > > > > >>
> > > > > > >>
> > > > > > >>
> > > > > > >> 611. What do we return if the request offset/epoch doesn't exist
> > > in the
> > > > > > >> following API?
> > > > > > >> RemoteLogSegmentMetadata remoteLogSegmentMetadata(TopicPartition
> > > > > > >> topicPartition, long offset, int epochForOffset)
> > > > > > >>
> > > > > > >>
> > > > > > >>
> > > > > > >> Jun
> > > > > > >>
> > > > > > >>
> > > > > > >>
> > > > > > >> On Mon, Aug 31, 2020 at 11:19 AM Satish Duggana < satish.
> > duggana@
> > > > > > gmail. com
> > > > > > >> ( satish.duggana@gmail.com ) > wrote:
> > > > > > >>
> > > > > > >>
> > > > > > >>>
> > > > > > >>>
> > > > > > >>> KIP is updated with
> > > > > > >>> - Remote log segment metadata topic message format/schema.
> > > > > > >>> - Added remote log segment metadata state transitions and
> > > explained how
> > > > > > >>> the deletion of segments is handled, including the case of
> > > partition
> > > > > > >>> deletions.
> > > > > > >>> - Added a few more limitations in the "Non goals" section.
> > > > > > >>>
> > > > > > >>>
> > > > > > >>>
> > > > > > >>> Thanks,
> > > > > > >>> Satish.
> > > > > > >>>
> > > > > > >>>
> > > > > > >>>
> > > > > > >>> On Thu, Aug 27, 2020 at 12:42 AM Harsha Ch < harsha. ch@
> > gmail.
> > > com (
> > > > > > >>> harsha.ch@gmail.com ) > wrote:
> > > > > > >>>
> > > > > > >>>
> > > > > > >>>>
> > > > > > >>>>
> > > > > > >>>> Updated the KIP with Meeting Notes section
> > > > > > >>>>
> > > > > > >>>>
> > > > > > >>>
> > > > > > >>>
> > > > > > >>>
> > > > > > >>> https:/ / cwiki. apache. org/ confluence/ display/ KAFKA/
> > > > > > KIP-405 <https://issues.apache.org/jira/browse/KIP-405>
> > > %3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> > > > > > >>> (
> > > > > > >>>
> > > > > >
> > >
> > https://cwiki.apache.org/confluence/display/KAFKA/KIP-405%3A+Kafka+Tiered+Storage#KIP405:KafkaTieredStorage-MeetingNotes
> > > > > > >>> )
> > > > > > >>>
> > > > > > >>>
> > > > > > >>>>
> > > > > > >>>>
> > > > > > >>>> On Tue, Aug 25, 2020 at 1:03 PM Jun Rao < jun@ confluent. io
> > (
> > > > > > >>>> jun@confluent.io ) > wrote:
> > > > > > >>>>
> > > > > > >>>>
> > > > > > >>>>>
> > > > > > >>>>>
> > > > > > >>>>> Hi, Harsha,
> > > > > > >>>>>
> > > > > > >>>>>
> > > > > > >>>>>
> > > > > > >>>>> Thanks for the summary. Could you add the summary and the
> > > recording
> > > > > > >>>>>
> > > > > > >>>>>
> > > > > > >>>>
> > > > > > >>>>
> > > > > > >>>
> > > > > > >>>
> > > > > > >>>
> > > > > > >>> link to
> > > > > > >>>
> > > > > > >>>
> > > > > > >>>>
> > > > > > >>>>>
> > > > > > >>>>>
> > > > > > >>>>> the last section of
> > > > > > >>>>>
> > > > > > >>>>>
> > > > > > >>>>
> > > > > > >>>>
> > > > > > >>>
> > > > > > >>>
> > > > > > >>>
> > > > > > >>> https:/ / cwiki. apache. org/ confluence/ display/ KAFKA/
> > > > > > Kafka+Improvement+Proposals
> > > > > > >>> (
> > > > > > >>>
> > > > > >
> > >
> > https://cwiki.apache.org/confluence/display/KAFKA/Kafka+Improvement+Proposals
> > > > > > >>> )
> > > > > > >>>
> > > > > > >>>
> > > > > > >>>>
> > > > > > >>>>>
> > > > > > >>>>>
> > > > > > >>>>> ?
> > > > > > >>>>>
> > > > > > >>>>>
> > > > > > >>>>>
> > > > > > >>>>> Jun
> > > > > > >>>>>
> > > > > > >>>>>
> > > > > > >>>>>
> > > > > > >>>>> On Tue, Aug 25, 2020 at 11:12 AM Harsha Chintalapani < kafka@
> > > > > > harsha. io (
> > > > > > >>>>> kafka@harsha.io ) > wrote:
> > > > > > >>>>>
> > > > > > >>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>> Thanks everyone for attending the meeting today.
> > > > > > >>>>>> Here is the recording
> > > > > > >>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>
> > > > > > >>>>>
> > > > > > >>>>
> > > > > > >>>>
> > > > > > >>>
> > > > > > >>>
> > > > > > >>>
> > > > > > >>> https:/ / drive. google. com/ file/ d/
> > > > > > 14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/ view?usp=sharing
> > > > > > >>> (
> > > > > > >>>
> > > > > >
> > >
> > https://drive.google.com/file/d/14PRM7U0OopOOrJR197VlqvRX5SXNtmKj/view?usp=sharing
> > > > > > >>> )
> > > > > > >>>
> > > > > > >>>
> > > > > > >>>>
> > > > > > >>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>> Notes:
> > > > > > >>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>> 1. KIP is updated with follower fetch protocol and ready to
> > > > > > >>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>
> > > > > > >>>>>
> > > > > > >>>>
> > > > > > >>>>
> > > > > > >>>
> > > > > > >>>
> > > > > > >>>
> > > > > > >>> reviewed
> > > > > > >>>
> > > > > > >>>
> > > > > > >>>>
> > > > > > >>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>> 2. Satish to capture schema of internal metadata topic in
> > the
> > > KIP
> > > > > > >>>>>> 3. We will update the KIP with details of different cases
> > > > > > >>>>>> 4. Test plan will be captured in a doc and will add to the
> > KIP
> > > > > > >>>>>> 5. Add a section "Limitations" to capture the capabilities
> > > that
> > > > > > >>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>
> > > > > > >>>>>
> > > > > > >>>>
> > > > > > >>>>
> > > > > > >>>
> > > > > > >>>
> > > > > > >>>
> > > > > > >>> will
> > > > > > >>>
> > > > > > >>>
> > > > > > >>>>
> > > > > > >>>>>
> > > > > > >>>>>
> > > > > > >>>>> be
> > > > > > >>>>>
> > > > > > >>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>> introduced with this KIP and what will not be covered in
> > this
> > > KIP.
> > > > > > >>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>> Please add to it I missed anything. Will produce a formal
> > > meeting
> > > > > > >>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>
> > > > > > >>>>>
> > > > > > >>>>
> > > > > > >>>>
> > > > > > >>>
> > > > > > >>>
> > > > > > >>>
> > > > > > >>> notes
> > > > > > >>>
> > > > > > >>>
> > > > > > >>>>
> > > > > > >>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>> from next meeting onwards.
> > > > > > >>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>> Thanks,
> > > > > > >>>>>> Harsha
> > > > > > >>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>> On Mon, Aug 24, 2020 at 9:42 PM, Ying Zheng < yingz@ uber.
> > > com.
> > > > > > invalid (
> > > > > > >>>>>> yingz@uber.com.invalid ) > wrote:
> > > > > > >>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> We did some basic feature tests at Uber. The test cases and
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>
> > > > > > >>>>>
> > > > > > >>>>
> > > > > > >>>>
> > > > > > >>>
> > > > > > >>>
> > > > > > >>>
> > > > > > >>> results are
> > > > > > >>>
> > > > > > >>>
> > > > > > >>>>
> > > > > > >>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> shared in this google doc:
> > > > > > >>>>>>> https:/ / docs. google. com/ spreadsheets/ d/ (
> > > > > > >>>>>>> https://docs.google.com/spreadsheets/d/ )
> > > > > > >>>>>>>
> > 1XhNJqjzwXvMCcAOhEH0sSXU6RTvyoSf93DHF-YMfGLk/edit?usp=sharing
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> The performance test results were already shared in the KIP
> > > last
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>
> > > > > > >>>>>
> > > > > > >>>>
> > > > > > >>>>
> > > > > > >>>
> > > > > > >>>
> > > > > > >>>
> > > > > > >>> month.
> > > > > > >>>
> > > > > > >>>
> > > > > > >>>>
> > > > > > >>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> On Mon, Aug 24, 2020 at 11:10 AM Harsha Ch < harsha. ch@
> > > gmail.
> > > > > > com (
> > > > > > >>>>>>> harsha.ch@gmail.com ) >
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>
> > > > > > >>>>>
> > > > > > >>>>>
> > > > > > >>>>> wrote:
> > > > > > >>>>>
> > > > > > >>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> "Understand commitments towards driving design &
> > > implementation of
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>
> > > > > > >>>>>
> > > > > > >>>>
> > > > > > >>>>
> > > > > > >>>
> > > > > > >>>
> > > > > > >>>
> > > > > > >>> the
> > > > > > >>>
> > > > > > >>>
> > > > > > >>>>
> > > > > > >>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>> KIP
> > > > > > >>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> further and how it aligns with participant interests in
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>
> > > > > > >>>>>
> > > > > > >>>>
> > > > > > >>>>
> > > > > > >>>
> > > > > > >>>
> > > > > > >>>
> > > > > > >>> contributing to
> > > > > > >>>
> > > > > > >>>
> > > > > > >>>>
> > > > > > >>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>> the
> > > > > > >>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> efforts (ex: in the context of Uber’s Q3/Q4 roadmap)." What
> > > is that
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>> about?
> > > > > > >>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> On Mon, Aug 24, 2020 at 11:05 AM Kowshik Prakasam <
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>> kprakasam@ confluent. io ( kprakasam@confluent.io ) >
> > > > > > >>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> wrote:
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> Hi Harsha,
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> The following google doc contains a proposal for temporary
> > > agenda
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>
> > > > > > >>>>>
> > > > > > >>>>
> > > > > > >>>>
> > > > > > >>>
> > > > > > >>>
> > > > > > >>>
> > > > > > >>> for
> > > > > > >>>
> > > > > > >>>
> > > > > > >>>>
> > > > > > >>>>>
> > > > > > >>>>>
> > > > > > >>>>> the
> > > > > > >>>>>
> > > > > > >>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> KIP-405 <https://issues.apache.org/jira/browse/KIP-405> <
> > > https:/ / issues. apache. org/ jira/ browse/ KIP-405
> > > <https://issues.apache.org/jira/browse/KIP-405> (
> > > > > > >>>>>>> https://issues.apache.org/jira/browse/KIP-405 ) > sync
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>
> > > > > > >>>>>
> > > > > > >>>>
> > > > > > >>>>
> > > > > > >>>
> > > > > > >>>
> > > > > > >>>
> > > > > > >>> meeting
> > > > > > >>>
> > > > > > >>>
> > > > > > >>>>
> > > > > > >>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> tomorrow:
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> https:/ / docs. google. com/ document/ d/ (
> > > > > > >>>>>>> https://docs.google.com/document/d/ )
> > > > > > >>>>>>> 1pqo8X5LU8TpwfC_iqSuVPezhfCfhGkbGN2TqiPA3LBU/edit
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> .
> > > > > > >>>>>>> Please could you add it to the Google calendar invite?
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> Thank you.
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> Cheers,
> > > > > > >>>>>>> Kowshik
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> On Thu, Aug 20, 2020 at 10:58 AM Harsha Ch < harsha. ch@
> > > gmail.
> > > > > > com (
> > > > > > >>>>>>> harsha.ch@gmail.com ) >
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>
> > > > > > >>>>>
> > > > > > >>>>>
> > > > > > >>>>> wrote:
> > > > > > >>>>>
> > > > > > >>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> Hi All,
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> Scheduled a meeting for Tuesday 9am - 10am. I can record
> > and
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>
> > > > > > >>>>>
> > > > > > >>>>
> > > > > > >>>>
> > > > > > >>>
> > > > > > >>>
> > > > > > >>>
> > > > > > >>> upload for
> > > > > > >>>
> > > > > > >>>
> > > > > > >>>>
> > > > > > >>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> community to be able to follow the discussion.
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> Jun, please add the required folks on confluent side.
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> Thanks,
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> Harsha
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> On Thu, Aug 20, 2020 at 12:33 AM, Alexandre Dupriez <
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>
> > > > > > >>>>>
> > > > > > >>>>>
> > > > > > >>>>> alexandre.dupriez@
> > > > > > >>>>>
> > > > > > >>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> gmail. com ( http://gmail.com/ ) > wrote:
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> Hi Jun,
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> Many thanks for your initiative.
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> If you like, I am happy to attend at the time you
> > suggested.
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> Many thanks,
> > > > > > >>>>>>> Alexandre
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> Le mer. 19 août 2020 à 22:00, Harsha Ch < harsha. ch@
> > > gmail. com (
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>> harsha.
> > > > > > >>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> ch@ gmail. com ( ch@gmail.com ) ) > a écrit :
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> Hi Jun,
> > > > > > >>>>>>> Thanks. This will help a lot. Tuesday will work for us.
> > > > > > >>>>>>> -Harsha
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> On Wed, Aug 19, 2020 at 1:24 PM Jun Rao < jun@ confluent.
> > > io (
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>
> > > > > > >>>>>
> > > > > > >>>>
> > > > > > >>>>
> > > > > > >>>
> > > > > > >>>
> > > > > > >>>
> > > > > > >>> jun@
> > > > > > >>>
> > > > > > >>>
> > > > > > >>>>
> > > > > > >>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> confluent. io ( http://confluent.io/ ) ) > wrote:
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> Hi, Satish, Ying, Harsha,
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> Do you think it would be useful to have a regular virtual
> > > meeting
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>
> > > > > > >>>>>
> > > > > > >>>>>
> > > > > > >>>>
> > > > > > >>>>
> > > > > > >>>
> > > > > > >>>
> > > > > > >>>
> > > > > > >>> to
> > > > > > >>>
> > > > > > >>>
> > > > > > >>>>
> > > > > > >>>>>
> > > > > > >>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> discuss this KIP? The goal of the meeting will be sharing
> > > > > > >>>>>>> design/development progress and discussing any open issues
> > to
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> accelerate
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> this KIP. If so, will every Tuesday (from next week)
> > 9am-10am
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> PT
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> work for you? I can help set up a Zoom meeting, invite
> > > everyone who
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> might
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> be interested, have it recorded and shared, etc.
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> Thanks,
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> Jun
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> On Tue, Aug 18, 2020 at 11:01 AM Satish Duggana <
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> satish. duggana@ gmail. com ( satish. duggana@ gmail. com
> > (
> > > > > > >>>>>>> satish.duggana@gmail.com ) ) >
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> wrote:
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> Hi Kowshik,
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> Thanks for looking into the KIP and sending your comments.
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>>
> > > > > > >>>>>>> 5001. Under the section "Follower fetch protocol in
> > detail",
> > > the
> > > > > > >>>>>>> next-local-offset is the offset upto which the segments are
> > > copied
> > > > > > >>>>>>>
> > >