Re: [DISCUSS] KIP-793: Sink Connectors: Support topic-mutating SMTs for async connectors (preCommit users)

[Greg Harris <gr...@aiven.io.INVALID>]

Hi Yash,

I always use this issue as an example of a bug being caused by design
rather than by implementation error, and once it's fixed I'll need to find
something else to talk about :)
So glad to see this get fixed!

I'll chime in to support some of the earlier discussions that seem to have
been resolved:

1. With respect to SinkRecord methods vs an overloaded put(): I agree with
the current design but I justify it a little bit differently than has
already been discussed.
If we were designing this interface on day 1 without backwards
compatibility in mind, which design would make more sense? Or for a
different framing: In the future when old runtimes and connectors are
retired and the old interfaces are removed, which design is going to look
more strange and unmotivated?
Applied to this design decision, I would say that the original T/P/O are
properties of a single SinkRecord and make sense as getters, and it would
be strange to store them in an auxiliary map.

2. Following up this change with a compatibility library to make the
interface easier to use is the right choice to make here. This change
should be focused on correctness in allowing developers to fix the
incompatibility and we can be concerned with coming up with a more
ergonomic solution in the compatibility library.
The API should be focused on generality, correctness, and performance
because those cannot be worked-around after the fact. Connector
implementations and/or libraries can be concerned with trading off some
generality and/or performance for ease-of-use.

3. I think that the difference in behavior of the new open/close methods as
compared to the old methods is significant, and requires good documentation
to help connector developers avoid lazy and incorrect migrations. I am
happy to have that addressed in code review after the KIP is approved.

I had some questions:

4. What is the expected state/behavior for SinkRecords which do not have
original T/P/O information after the upgrade? Just browsing, it appears
that tests make extensive use of the existing public SinkRecord
constructors for both Transformations and Connectors.

5. What is the expected behavior for Transformation implementations which
do not use the newRecord methods and instead use public SinkRecord
constructors? The KIP mentions this as a justification for the
originalKafkaOffset method, but if existing implementations are using the
existing constructors, those constructors won't forward the original T/P/O
information to later transforms or the task.

For the last few points, I want to discuss this rejected alternative:

> Address the offsets problem entirely within the framework, doing some
kind of mapping from the transformed topic back to the original topic.
> * This would only work in the cases where there’s no overlap between the
transformed topic names, but would break for the rest of the
transformations (e.g. static transformation, topic = “a”).
> * Even if we wanted to limit the support to those cases, it would require
considerable bookkeeping to add a validation to verify that the
transformation chain adheres to that expectation (and fail fast if it
doesn’t).

6. This reasoning and the KIP design seems to imply that the connector is
better equipped to solve this problem than the framework, but the stated
reasons are not convincing for me.
* A static transformation still causes an offset collision in the connector
* The connector is not permitted to see the transformation chain to do any
fail-fast assertions

Suppose we were to think of the records at the end of the transformation
chain as being in "virtual partitions" with "virtual offsets".
For example, with identity-routing SMTs, the virtual coordinates are
exactly the same as the underlying physical coordinates. For 1-1 renames,
each virtual topic would be the renamed topic corresponding to the
underlying topic. For fan-out from one topic to multiple virtual topics,
virtual offsets would use the underlying kafka offsets with gaps for
records going to other virtual partitions. Virtual topics with dropped
records have similar gaps in the offsets.
Currently, these virtual coordinates are passed into the connector via
SinkTask::put, but SinkTask::open/close/preCommit and
SinkTaskContext::assignment/offsets/pause/resume all use physical
coordinates.
This proposal patches put,open, and close to have both physical and virtual
coordinates, but leaves the other methods with physical coordinates. After
this proposal, connectors would be intentionally made aware of the
distinction between physical and virtual coordinates, and manage their own
bookkeeping for the two systems.

To avoid that connector logic, we could use virtual coordinates in all
connector calls, never revealing that they are different from the physical
coordinates. There's a whole design shopping list that we'd need:
* Renumbering mechanism for disambiguating and making virtual offsets
monotonic in the case of topic/partition collisions
* Data structure and strategy for translating virtual offsets back to
physical offsets
* New limits on SinkTaskContext::offsets() calls to prevent rewinding
before the latest commit
* Backwards compatibility and upgrade design

7. This alternative was very appealing to me, because the strength of a
plugin framework is the composability of different components. Among a
collection of N connectors and M transforms, it should ideally only take
N + M work to understand how the components combine to build the whole.
However, once you start adding special cases to some plugins to support
interactions with others, the whole system can take N * M work to
understand. From a complexity standpoint, it would be very good for the
framework to solve this in a way which was connector-agnostic.
The current design compromises the logical isolation of the plugins
slightly, but they can collapse offsets very memory-efficiently, and re-use
the existing raw coordinate functions and keep everything else backwards
compatible. After deriving all of the above, I think that's a reasonable
tradeoff to make.

Thanks,
Greg

On Tue, Feb 21, 2023 at 10:17 AM Chris Egerton <ch...@aiven.io.invalid>
wrote:

> Hi Yash,
>
> We'll probably want to make a few tweaks to the Javadocs for the new
> methods (I'm imagining that notes on compatibility with older versions will
> be required), but I believe what's proposed in the KIP is good enough to
> approve with the understanding that it may not exactly match what gets
> implemented/merged.
>
> LGTM, thanks again for the KIP!
>
> Cheers,
>
> Chris
>
> On Tue, Feb 21, 2023 at 12:18 PM Yash Mayya <ya...@gmail.com> wrote:
>
> > Hi Chris,
> >
> > > we might try to introduce a framework-level configuration
> > > property to dictate which of the pre-transform and post-transform
> > > topic partitions are used for the fallback call to the single-arg
> > > variant if a task class has not overridden the multi-arg variant
> >
> > Thanks for the explanation and I agree that this will be a tad bit too
> > convoluted. :)
> >
> > Please do let me know if you'd like any further amendments to the KIP!
> >
> > Thanks,
> > Yash
> >
> > On Tue, Feb 21, 2023 at 8:42 PM Chris Egerton <ch...@aiven.io.invalid>
> > wrote:
> >
> > > Hi Yash,
> > >
> > > I think the use case for pre-transform TPO coordinates (and topic
> > partition
> > > writers created/destroyed in close/open) tends to boil down to
> > exactly-once
> > > semantics, where it's desirable to preserve the guarantees that Kafka
> > > provides (every record has a unique TPO trio, and records are ordered
> by
> > > offset within a topic partition).
> > >
> > > It's my understanding that this approach is utilized in several
> > connectors
> > > out there today, and it might break these connectors to start using the
> > > post-transform topic partitions automatically in their open/close
> > methods.
> > >
> > > If we want to get really fancy with this and try to obviate or at least
> > > reduce the need for per-connector code changes, we might try to
> > introduce a
> > > framework-level configuration property to dictate which of the
> > > pre-transform and post-transform topic partitions are used for the
> > fallback
> > > call to the single-arg variant if a task class has not overridden the
> > > multi-arg variant. But I think this is going a bit too far and would
> > prefer
> > > to keep things simple(r) for now.
> > >
> > > Cheers,
> > >
> > > Chris
> > >
> > >
> > > On Sun, Feb 19, 2023 at 2:34 AM Yash Mayya <ya...@gmail.com>
> wrote:
> > >
> > > > Hi Chris,
> > > >
> > > > > I was actually envisioning something like `void
> > > > > open(Collection<TopicPartition> originalPartitions,
> > > > > Collection<TopicPartition> transformedPartitions)`
> > > >
> > > > Ah okay, this does make a lot more sense. Sorry, I think I
> > misunderstood
> > > > you earlier. I do agree with you that this seems better than
> splitting
> > it
> > > > off into two new sets of open / close methods from a complexity
> > > standpoint.
> > > >
> > > > > Plus, if a connector is intentionally designed to use
> > > > > pre-transformation topic partitions in its open/close
> > > > > methods, wouldn't we just be trading one form of the
> > > > >  problem for another by making this switch?
> > > >
> > > > On thinking about this a bit more, I'm not so convinced that we need
> to
> > > > expose the pre-transform / original topic partitions in the new open
> /
> > > > close methods. The purpose of the open / close methods is to allow
> sink
> > > > tasks to allocate and deallocate resources for each topic partition
> > > > assigned to the task and the purpose of topic-mutating SMTs is to
> > > > essentially modify the source topic name from the point of view of
> the
> > > sink
> > > > connector. Why would a sink connector ever need to or want to
> allocate
> > > > resources for pre-transform topic partitions? Is the argument here
> that
> > > > since we'll be exposing both the pre-transform and post-transform
> topic
> > > > partitions per record, we should also expose the same info via open /
> > > close
> > > > and allow sink connector implementations to disregard topic-mutating
> > SMTs
> > > > completely if they wanted to?
> > > >
> > > > Either way, I've gone ahead and updated the KIP to reflect all of
> > > > our previous discussion here since it had become quite outdated. I've
> > > also
> > > > updated the KIP title from "Sink Connectors: Support topic-mutating
> > SMTs
> > > > for async connectors (preCommit users)" to "Allow sink connectors to
> be
> > > > used with topic-mutating SMTs" since the improvements to the open /
> > close
> > > > mechanism doesn't pertain only to asynchronous sink connectors. The
> new
> > > KIP
> > > > URL is:
> > > >
> > > >
> > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-793%3A+Allow+sink+connectors+to+be+used+with+topic-mutating+SMTs
> > > >
> > > >
> > > > Thanks,
> > > > Yash
> > > >
> > > > On Tue, Feb 14, 2023 at 11:39 PM Chris Egerton
> <chrise@aiven.io.invalid
> > >
> > > > wrote:
> > > >
> > > > > Hi Yash,
> > > > >
> > > > > I was actually envisioning something like `void
> > > > > open(Collection<TopicPartition>
> > > > > originalPartitions, Collection<TopicPartition>
> > transformedPartitions)`,
> > > > > since we already convert and transform each batch of records that
> we
> > > poll
> > > > > from the sink task's consumer en masse, meaning we could discover
> > > several
> > > > > new transformed partitions in between consecutive calls to
> > > SinkTask::put.
> > > > >
> > > > > It's also worth noting that we'll probably want to deprecate the
> > > existing
> > > > > open/close methods, at which point keeping one non-deprecated
> variant
> > > of
> > > > > each seems more appealing and less complex than keeping two.
> > > > >
> > > > > Honestly though, I think we're both on the same page enough that I
> > > > wouldn't
> > > > > object to either approach. We've probably reached the saturation
> > point
> > > > for
> > > > > ROI here and as long as we provide developers a way to get the
> > > > information
> > > > > they need from the runtime and take care to add Javadocs and update
> > our
> > > > > docs page (possibly including the connector development
> quickstart),
> > it
> > > > > should be fine.
> > > > >
> > > > > At this point, it might be worth updating the KIP based on recent
> > > > > discussion so that others can see the latest proposal, and we can
> > both
> > > > take
> > > > > a look and make sure everything looks good enough before opening a
> > vote
> > > > > thread.
> > > > >
> > > > > Finally, I think you make a convincing case for a time-based
> eviction
> > > > > policy. I wasn't thinking about the fairly common SMT pattern of
> > > > deriving a
> > > > > topic name from, e.g., a record field or header.
> > > > >
> > > > > Cheers,
> > > > >
> > > > > Chris
> > > > >
> > > > > On Tue, Feb 14, 2023 at 11:42 AM Yash Mayya <ya...@gmail.com>
> > > > wrote:
> > > > >
> > > > > > Hi Chris,
> > > > > >
> > > > > > > Plus, if a connector is intentionally designed to
> > > > > > > use pre-transformation topic partitions in its
> > > > > > > open/close methods, wouldn't we just be trading
> > > > > > > one form of the problem for another by making this
> > > > > > > switch?
> > > > > >
> > > > > > Thanks, this makes sense, and given that the KIP already
> proposes a
> > > way
> > > > > for
> > > > > > sink connector implementations to distinguish between
> pre-transform
> > > and
> > > > > > post-transform topics per record, I think I'm convinced that
> going
> > > with
> > > > > new
> > > > > > `open()` / `close()` methods is the right approach. However, I
> > still
> > > > feel
> > > > > > like having overloaded methods will make it a lot less
> unintuitive
> > > > given
> > > > > > that the two sets of methods would be different in terms of when
> > > > they're
> > > > > > called and what arguments they are passed (also I'm presuming
> that
> > > the
> > > > > > overloaded methods you're prescribing will only have a single
> > > > > > `TopicPartition` rather than a `Collection<TopicPartition>` as
> > their
> > > > > > parameters). I guess my concern is largely around the fact that
> it
> > > > won't
> > > > > be
> > > > > > possible to distinguish between the overloaded methods' use cases
> > > just
> > > > > from
> > > > > > the method signatures. I agree that naming is going to be
> difficult
> > > > here,
> > > > > > but I think that having two sets of `SinkTask::openXyz` /
> > > > > > `SinkTask::closeXyz` methods will be less complicated to
> understand
> > > > from
> > > > > a
> > > > > > connector developer perspective (as compared to overloaded
> methods
> > > with
> > > > > > only differing documentation). Of your suggested options, I think
> > > > > > `openPreTransform` / `openPostTransform` are the most
> > comprehensible
> > > > > ones.
> > > > > >
> > > > > > > BTW, I wouldn't say that we can't make assumptions
> > > > > > > about the relationships between pre- and post-transformation
> > > > > > >  topic partitions.
> > > > > >
> > > > > > I meant that the framework wouldn't be able to deterministically
> > know
> > > > > when
> > > > > > to close a post-transform topic partition given that SMTs could
> use
> > > > > > per-record data / metadata to manipulate the topic names as and
> how
> > > > > > required (which supports the suggestion to use an eviction policy
> > > based
> > > > > > mechanism to call SinkTask::close for post-transform topic
> > > partitions).
> > > > > >
> > > > > > > We might utilize a policy that assumes a deterministic
> > > > > > > mapping from the former to the latter, for example.
> > > > > >
> > > > > > Wouldn't this be making the assumption that SMTs only use the
> topic
> > > > name
> > > > > > itself and no other data / metadata while computing the new topic
> > > name?
> > > > > Are
> > > > > > you suggesting that since this assumption could work for a
> majority
> > > of
> > > > > > SMTs, it might be more efficient overall in terms of reducing the
> > > > number
> > > > > of
> > > > > > "false-positive" calls to `SinkTask::closePostTransform` (and
> we'll
> > > > also
> > > > > be
> > > > > > able to call `SinkTask::closePostTransform` immediately after
> topic
> > > > > > partitions are revoked from the consumer)? I was thinking
> something
> > > > more
> > > > > > generic along the lines of a simple time based eviction policy
> that
> > > > > > wouldn't be making any assumptions regarding the SMT
> > implementations.
> > > > > > Either way, I do like your earlier suggestion of keeping this
> logic
> > > > > > internal and not painting ourselves into a corner by promising
> any
> > > > > > particular behavior in the KIP.
> > > > > >
> > > > > > Thanks,
> > > > > > Yash
> > > > > >
> > > > > > On Tue, Feb 14, 2023 at 1:08 AM Chris Egerton
> > > <chrise@aiven.io.invalid
> > > > >
> > > > > > wrote:
> > > > > >
> > > > > > > Hi Yash,
> > > > > > >
> > > > > > > I think the key difference between adding methods/overloads
> > related
> > > > to
> > > > > > > SinkTask::open/SinkTask::close and SinkTask::put is that this
> > isn't
> > > > > > > auxiliary information that may or may not be useful to
> connector
> > > > > > > developers. It's actually critical for them to understand the
> > > > > difference
> > > > > > > between the two concepts here, even if they look very similar.
> > And
> > > > > yes, I
> > > > > > > do believe that switching from pre-transform to post-transform
> > > topic
> > > > > > > partitions is too big a change in behavior here. Plus, if a
> > > connector
> > > > > is
> > > > > > > intentionally designed to use pre-transformation topic
> partitions
> > > in
> > > > > its
> > > > > > > open/close methods, wouldn't we just be trading one form of the
> > > > problem
> > > > > > for
> > > > > > > another by making this switch?
> > > > > > >
> > > > > > > One possible alternative to overloading the existing methods is
> > to
> > > > > split
> > > > > > > SinkTask::open into openOriginal (or possibly openPhysical or
> > > > > > > openPreTransform) and openTransformed (or openLogical or
> > > > > > > openPostTransform), with a similar change for SinkTask::close.
> > The
> > > > > > default
> > > > > > > implementation for SinkTask::openOriginal can be to call
> > > > > SinkTask::open,
> > > > > > > and the same can go for SinkTask::close. However, I prefer
> > > > overloading
> > > > > > the
> > > > > > > existing methods since this alternative increases complexity
> and
> > > none
> > > > > of
> > > > > > > the names are very informative.
> > > > > > >
> > > > > > > BTW, I wouldn't say that we can't make assumptions about the
> > > > > > relationships
> > > > > > > between pre- and post-transformation topic partitions. We might
> > > > > utilize a
> > > > > > > policy that assumes a deterministic mapping from the former to
> > the
> > > > > > latter,
> > > > > > > for example. The distinction I'd draw is that the assumptions
> we
> > > make
> > > > > can
> > > > > > > and probably should favor some cases in terms of performance
> > (i.e.,
> > > > > > > reducing the number of unnecessary calls to close/open over a
> > given
> > > > > sink
> > > > > > > task's lifetime), but should not lead to guaranteed resource
> > leaks
> > > or
> > > > > > > failure to obey API contract in any cases.
> > > > > > >
> > > > > > > Cheers,
> > > > > > >
> > > > > > > Chris
> > > > > > >
> > > > > > > On Mon, Feb 13, 2023 at 10:54 AM Yash Mayya <
> > yash.mayya@gmail.com>
> > > > > > wrote:
> > > > > > >
> > > > > > > > Hi Chris,
> > > > > > > >
> > > > > > > > > especially if connectors are intentionally designed around
> > > > > > > > > original topic partitions instead of transformed ones.
> > > > > > > >
> > > > > > > > Ha, that's a good point and reminds me of Hyrum's Law [1] :)
> > > > > > > >
> > > > > > > > > I think we have to provide connector developers with some
> > > > > > > > > way to differentiate between the two, but maybe there's a
> way
> > > > > > > > >  to do this that I haven't thought of yet
> > > > > > > >
> > > > > > > > I can't think of a better way to do this either; would
> invoking
> > > the
> > > > > > > > existing `SinkTask::open` and `SinkTask::close` methods with
> > > > > > > post-transform
> > > > > > > > topic partitions instead of pre-transform topic partitions
> not
> > be
> > > > > > > > acceptable even in a minor / major AK release? I feel like
> the
> > > > > proposed
> > > > > > > > approach of adding overloaded `SinkTask::open` /
> > > `SinkTask::close`
> > > > > > > methods
> > > > > > > > to differentiate between pre-transform and post-transform
> topic
> > > > > > > partitions
> > > > > > > > has similar pitfalls to the idea of the overloaded
> > > `SinkTask::put`
> > > > > > method
> > > > > > > > we discarded earlier.
> > > > > > > >
> > > > > > > > > Either way, I'm glad that the general idea of a cache and
> > > > > > > > > eviction policy for SinkTask::close seem reasonable; if
> > > > > > > > > we decide to go this route, it might make sense for the KIP
> > > > > > > > > to include an outline of one or more high-level strategies
> > > > > > > > > we might take, but without promising any particular
> behavior
> > > > > > > > > beyond occasionally calling SinkTask::close for
> > post-transform
> > > > > > > > > topic partitions. I'm hoping that this logic can stay
> > internal,
> > > > > > > > > and by notpainting ourselves into a corner with the KIP, we
> > > > > > > > > give ourselves leeway to tweak it in the future if
> necessary
> > > > > > > > > without filing another KIP or introducing a pluggable
> > > interface.
> > > > > > > >
> > > > > > > > Thanks, that's a good idea. Given the flexibility of SMTs,
> the
> > > > > > framework
> > > > > > > > can't really make any assumptions around topic partitions
> post
> > > > > > > > transformation nor does it have any way to definitively get
> any
> > > > such
> > > > > > > > information from transformations which is why the idea of a
> > cache
> > > > > with
> > > > > > an
> > > > > > > > eviction policy makes perfect sense!
> > > > > > > >
> > > > > > > > [1] - https://www.hyrumslaw.com/
> > > > > > > >
> > > > > > > >
> > > > > > > > Thanks,
> > > > > > > > Yash
> > > > > > > >
> > > > > > > > On Thu, Feb 9, 2023 at 9:38 PM Chris Egerton
> > > > <chrise@aiven.io.invalid
> > > > > >
> > > > > > > > wrote:
> > > > > > > >
> > > > > > > > > Hi Yash,
> > > > > > > > >
> > > > > > > > > > So it looks like with the current state of affairs, sink
> > > tasks
> > > > > that
> > > > > > > > only
> > > > > > > > > instantiate writers in the SinkTask::open method (and don't
> > do
> > > > the
> > > > > > lazy
> > > > > > > > > instantiation in SinkTask::put that you mentioned) might
> fail
> > > > when
> > > > > > used
> > > > > > > > > with topic/partition mutating SMTs even if they don't do
> any
> > > > > > > asynchronous
> > > > > > > > > processing?
> > > > > > > > >
> > > > > > > > > Yep, exactly 👍
> > > > > > > > >
> > > > > > > > > > What do you think about retaining just the existing
> methods
> > > > > > > > > but changing when they're called in the Connect runtime?
> For
> > > > > > instance,
> > > > > > > > > instead of calling SinkTask::open after partition
> assignment
> > > > post a
> > > > > > > > > consumer group rebalance, we could cache the currently
> "seen"
> > > > topic
> > > > > > > > > partitions (post transformation) and before each call to
> > > > > > SinkTask::put
> > > > > > > > > check whether there's any new "unseen" topic partitions,
> and
> > if
> > > > so
> > > > > > call
> > > > > > > > > SinkTask::open (and also update the cache of course).
> > > > > > > > >
> > > > > > > > > IMO the issue here is that it's a drastic change in
> behavior
> > to
> > > > > start
> > > > > > > > > invoking SinkTask::open and SinkTask::close with
> > post-transform
> > > > > topic
> > > > > > > > > partitions instead of pre-transform, especially if
> connectors
> > > are
> > > > > > > > > intentionally designed around original topic partitions
> > instead
> > > > of
> > > > > > > > > transformed ones. I think we have to provide connector
> > > developers
> > > > > > with
> > > > > > > > some
> > > > > > > > > way to differentiate between the two, but maybe there's a
> way
> > > to
> > > > do
> > > > > > > this
> > > > > > > > > that I haven't thought of yet. Interested to hear your
> > > thoughts.
> > > > > > > > >
> > > > > > > > > Either way, I'm glad that the general idea of a cache and
> > > > eviction
> > > > > > > policy
> > > > > > > > > for SinkTask::close seem reasonable; if we decide to go
> this
> > > > route,
> > > > > > it
> > > > > > > > > might make sense for the KIP to include an outline of one
> or
> > > more
> > > > > > > > > high-level strategies we might take, but without promising
> > any
> > > > > > > particular
> > > > > > > > > behavior beyond occasionally calling SinkTask::close for
> > > > > > post-transform
> > > > > > > > > topic partitions. I'm hoping that this logic can stay
> > internal,
> > > > and
> > > > > > by
> > > > > > > > not
> > > > > > > > > painting ourselves into a corner with the KIP, we give
> > > ourselves
> > > > > > leeway
> > > > > > > > to
> > > > > > > > > tweak it in the future if necessary without filing another
> > KIP
> > > or
> > > > > > > > > introducing a pluggable interface.
> > > > > > > > >
> > > > > > > > > Cheers,
> > > > > > > > >
> > > > > > > > > Chris
> > > > > > > > >
> > > > > > > > > On Thu, Feb 9, 2023 at 7:39 AM Yash Mayya <
> > > yash.mayya@gmail.com>
> > > > > > > wrote:
> > > > > > > > >
> > > > > > > > > > Hi Chris,
> > > > > > > > > >
> > > > > > > > > > Thanks for the feedback.
> > > > > > > > > >
> > > > > > > > > > 1) That's a fair point; while I did scan everything
> > publicly
> > > > > > > available
> > > > > > > > on
> > > > > > > > > > GitHub, you're right in that it won't cover all possible
> > SMTs
> > > > > that
> > > > > > > are
> > > > > > > > > out
> > > > > > > > > > there. Thanks for the example use-case as well, I've
> > updated
> > > > the
> > > > > > KIP
> > > > > > > to
> > > > > > > > > add
> > > > > > > > > > the two new proposed methods.
> > > > > > > > > >
> > > > > > > > > > 2) So it looks like with the current state of affairs,
> sink
> > > > tasks
> > > > > > > that
> > > > > > > > > only
> > > > > > > > > > instantiate writers in the SinkTask::open method (and
> don't
> > > do
> > > > > the
> > > > > > > lazy
> > > > > > > > > > instantiation in SinkTask::put that you mentioned) might
> > fail
> > > > > when
> > > > > > > used
> > > > > > > > > > with topic/partition mutating SMTs even if they don't do
> > any
> > > > > > > > asynchronous
> > > > > > > > > > processing? Since they could encounter records in
> > > SinkTask::put
> > > > > > with
> > > > > > > > > > topics/partitions that they might not have created
> writers
> > > for.
> > > > > > > Thanks
> > > > > > > > > for
> > > > > > > > > > pointing this out, it's definitely another
> incompatibility
> > > that
> > > > > > needs
> > > > > > > > to
> > > > > > > > > be
> > > > > > > > > > called out and fixed. The overloaded method approach is
> > > > > > interesting,
> > > > > > > > but
> > > > > > > > > > comes with the caveat of yet more new methods that will
> > need
> > > to
> > > > > be
> > > > > > > > > > implemented by existing connectors if they want to make
> use
> > > of
> > > > > this
> > > > > > > new
> > > > > > > > > > functionality. What do you think about retaining just the
> > > > > existing
> > > > > > > > > methods
> > > > > > > > > > but changing when they're called in the Connect runtime?
> > For
> > > > > > > instance,
> > > > > > > > > > instead of calling SinkTask::open after partition
> > assignment
> > > > > post a
> > > > > > > > > > consumer group rebalance, we could cache the currently
> > "seen"
> > > > > topic
> > > > > > > > > > partitions (post transformation) and before each call to
> > > > > > > SinkTask::put
> > > > > > > > > > check whether there's any new "unseen" topic partitions,
> > and
> > > if
> > > > > so
> > > > > > > call
> > > > > > > > > > SinkTask::open (and also update the cache of course). I
> > don't
> > > > > think
> > > > > > > > this
> > > > > > > > > > would break the existing contract with sink tasks where
> > > > > > > SinkTask::open
> > > > > > > > is
> > > > > > > > > > expected to be called for a topic partition before any
> > > records
> > > > > from
> > > > > > > the
> > > > > > > > > > topic partition are sent via SinkTask::put? The
> > > SinkTask::close
> > > > > > case
> > > > > > > > is a
> > > > > > > > > > lot trickier however, and would require some sort of
> cache
> > > > > eviction
> > > > > > > > > policy
> > > > > > > > > > that would be deemed appropriate as you pointed out too.
> > > > > > > > > >
> > > > > > > > > > Thanks,
> > > > > > > > > > Yash
> > > > > > > > > >
> > > > > > > > > > On Mon, Feb 6, 2023 at 11:27 PM Chris Egerton
> > > > > > > <chrise@aiven.io.invalid
> > > > > > > > >
> > > > > > > > > > wrote:
> > > > > > > > > >
> > > > > > > > > > > Hi Yash,
> > > > > > > > > > >
> > > > > > > > > > > I've had some time to think on this KIP and I think I'm
> > in
> > > > > > > agreement
> > > > > > > > > > about
> > > > > > > > > > > not blocking it on an official compatibility library or
> > > > adding
> > > > > > the
> > > > > > > > > "ack"
> > > > > > > > > > > API for sink records.
> > > > > > > > > > >
> > > > > > > > > > > I only have two more thoughts:
> > > > > > > > > > >
> > > > > > > > > > > 1. Because it is possible to manipulate sink record
> > > > partitions
> > > > > > and
> > > > > > > > > > offsets
> > > > > > > > > > > with the current API we provide for transformations, I
> > > still
> > > > > > > believe
> > > > > > > > > > > methods should be added to the SinkRecord class to
> expose
> > > the
> > > > > > > > original
> > > > > > > > > > > partition and offset, not just the original topic. The
> > > > > additional
> > > > > > > > > > cognitive
> > > > > > > > > > > burden from these two methods is going to be minimal
> > > anyways;
> > > > > > once
> > > > > > > > > users
> > > > > > > > > > > understand the difference between the transformed topic
> > > name
> > > > > and
> > > > > > > the
> > > > > > > > > > > original one, it's going to be trivial for them to
> > > understand
> > > > > how
> > > > > > > > that
> > > > > > > > > > same
> > > > > > > > > > > difference applies for partitions and offsets. It's not
> > > > enough
> > > > > to
> > > > > > > > scan
> > > > > > > > > > the
> > > > > > > > > > > set of SMTs provided out of the box with Connect, ones
> > > > > developed
> > > > > > by
> > > > > > > > > > > Confluent, or even everything available on GitHub,
> since
> > > > there
> > > > > > may
> > > > > > > be
> > > > > > > > > > > closed-source projects out there that rely on this
> > ability.
> > > > One
> > > > > > > > > potential
> > > > > > > > > > > use case could be re-routing partitions between Kafka
> and
> > > > some
> > > > > > > other
> > > > > > > > > > > sharded system.
> > > > > > > > > > >
> > > > > > > > > > > 2. We still have to address the SinkTask::open [1] and
> > > > > > > > SinkTask::close
> > > > > > > > > > [2]
> > > > > > > > > > > methods. If a connector writes to the external system
> > using
> > > > the
> > > > > > > > > > transformed
> > > > > > > > > > > topic partitions it reads from Kafka, then it's
> possible
> > > for
> > > > > the
> > > > > > > > > > connector
> > > > > > > > > > > to lazily instantiate writers for topic partitions as
> it
> > > > > > encounters
> > > > > > > > > them
> > > > > > > > > > > from records provided in SinkTask::put. However,
> > connectors
> > > > > also
> > > > > > > > need a
> > > > > > > > > > way
> > > > > > > > > > > to de-allocate those writers (and the resources used by
> > > them)
> > > > > > over
> > > > > > > > > time,
> > > > > > > > > > > which they can't do as easily. One possible approach
> here
> > > is
> > > > to
> > > > > > > > > overload
> > > > > > > > > > > SinkTask::open and SinkTask::close with variants that
> > > > > distinguish
> > > > > > > > > between
> > > > > > > > > > > transformed and original topic partitions, and default
> to
> > > > > > invoking
> > > > > > > > the
> > > > > > > > > > > existing methods with just the original topic
> partitions.
> > > We
> > > > > > would
> > > > > > > > then
> > > > > > > > > > > have several options for how the Connect runtime can
> > invoke
> > > > > these
> > > > > > > > > > methods,
> > > > > > > > > > > but in general, an approach that guarantees that tasks
> > are
> > > > > > notified
> > > > > > > > of
> > > > > > > > > > > transformed topic partitions in SinkTask::open before
> any
> > > > > records
> > > > > > > for
> > > > > > > > > > that
> > > > > > > > > > > partition are given to it in SinkTask::put, and makes a
> > > > > > best-effort
> > > > > > > > > > attempt
> > > > > > > > > > > to close transformed topic partitions that appear to no
> > > > longer
> > > > > be
> > > > > > > in
> > > > > > > > > use
> > > > > > > > > > > based on some eviction policy, would probably be
> > > sufficient.
> > > > > > > > > > >
> > > > > > > > > > > [1] -
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://kafka.apache.org/33/javadoc/org/apache/kafka/connect/sink/SinkTask.html#open(java.util.Collection)
> > > > > > > > > > > [2] -
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://kafka.apache.org/33/javadoc/org/apache/kafka/connect/sink/SinkTask.html#close(java.util.Collection)
> > > > > > > > > > >
> > > > > > > > > > > Cheers,
> > > > > > > > > > >
> > > > > > > > > > > Chris
> > > > > > > > > > >
> > > > > > > > > > > On Sat, Nov 5, 2022 at 5:46 AM Yash Mayya <
> > > > > yash.mayya@gmail.com>
> > > > > > > > > wrote:
> > > > > > > > > > >
> > > > > > > > > > > > Hi Chris,
> > > > > > > > > > > >
> > > > > > > > > > > > Thanks a lot for your inputs!
> > > > > > > > > > > >
> > > > > > > > > > > > > would provide a simple, clean interface for
> > developers
> > > to
> > > > > > > > determine
> > > > > > > > > > > > > which features are supported by the version of the
> > > > Connect
> > > > > > > > runtime
> > > > > > > > > > > > > that their plugin has been deployed onto
> > > > > > > > > > > >
> > > > > > > > > > > > I do like the idea of having such a public
> > compatibility
> > > > > > library
> > > > > > > -
> > > > > > > > I
> > > > > > > > > > > think
> > > > > > > > > > > > it would remove a lot of restrictions from framework
> > > > > > development
> > > > > > > if
> > > > > > > > > it
> > > > > > > > > > > were
> > > > > > > > > > > > to be widely adopted.
> > > > > > > > > > > >
> > > > > > > > > > > > > we might consider adding an API to "ack" sink
> records
> > > > > > > > > > > >
> > > > > > > > > > > > I agree that this does seem like a more intuitive and
> > > clean
> > > > > > API,
> > > > > > > > but
> > > > > > > > > > I'm
> > > > > > > > > > > > concerned about the backward compatibility headache
> > we'd
> > > be
> > > > > > > > imposing
> > > > > > > > > on
> > > > > > > > > > > all
> > > > > > > > > > > > existing sink connectors. Connector developers will
> > have
> > > to
> > > > > > > > maintain
> > > > > > > > > > two
> > > > > > > > > > > > separate ways of doing offset management if they want
> > to
> > > > use
> > > > > > the
> > > > > > > > new
> > > > > > > > > > API
> > > > > > > > > > > > but continue supporting older versions of Kafka
> > Connect.
> > > > > > > > > > > >
> > > > > > > > > > > > For now, I've reverted the KIP to the previous
> > iteration
> > > > > which
> > > > > > > > > proposed
> > > > > > > > > > > the
> > > > > > > > > > > > addition of a new `SinkRecord` method to obtain the
> > > > original
> > > > > > > Kafka
> > > > > > > > > > topic
> > > > > > > > > > > > pre-transformation. One thing to note is that I've
> > > removed
> > > > > the
> > > > > > > > method
> > > > > > > > > > for
> > > > > > > > > > > > obtaining the original Kafka partition after a
> cursory
> > > > search
> > > > > > > > showed
> > > > > > > > > > that
> > > > > > > > > > > > use cases for partition modifying SMTs are primarily
> on
> > > the
> > > > > > > source
> > > > > > > > > > > > connector side.
> > > > > > > > > > > >
> > > > > > > > > > > > Thanks,
> > > > > > > > > > > > Yash
> > > > > > > > > > > >
> > > > > > > > > > > > On Tue, Nov 1, 2022 at 9:22 PM Chris Egerton
> > > > > > > > <chrise@aiven.io.invalid
> > > > > > > > > >
> > > > > > > > > > > > wrote:
> > > > > > > > > > > >
> > > > > > > > > > > > > Hi all,
> > > > > > > > > > > > >
> > > > > > > > > > > > > I have more comments I'd like to make on this KIP
> > when
> > > I
> > > > > have
> > > > > > > > time
> > > > > > > > > > > (sorry
> > > > > > > > > > > > > for the delay, Yash, and thanks for your
> patience!),
> > > but
> > > > I
> > > > > > did
> > > > > > > > want
> > > > > > > > > > to
> > > > > > > > > > > > > chime in and say that I'm also not sure about
> > > overloading
> > > > > > > > > > > SinkTask::put.
> > > > > > > > > > > > I
> > > > > > > > > > > > > share the concerns about creating an intuitive,
> > simple
> > > > API
> > > > > > that
> > > > > > > > > Yash
> > > > > > > > > > > has
> > > > > > > > > > > > > raised. In addition, this approach doesn't seem
> very
> > > > > > > > > > sustainable--what
> > > > > > > > > > > do
> > > > > > > > > > > > > we do if we encounter another case in the future
> that
> > > > would
> > > > > > > > > warrant a
> > > > > > > > > > > > > similar solution? We probably don't want to create
> > > three,
> > > > > > four,
> > > > > > > > > etc.
> > > > > > > > > > > > > overloaded variants of the method, each of which
> > would
> > > > have
> > > > > > to
> > > > > > > be
> > > > > > > > > > > > > implemented by connector developers who want to
> both
> > > > > leverage
> > > > > > > the
> > > > > > > > > > > latest
> > > > > > > > > > > > > and greatest connector APIs and maintain
> > compatibility
> > > > with
> > > > > > > > connect
> > > > > > > > > > > > > Clusters running older versions.
> > > > > > > > > > > > >
> > > > > > > > > > > > > I haven't been able to flesh this out into a design
> > > worth
> > > > > > > > > publishing
> > > > > > > > > > in
> > > > > > > > > > > > its
> > > > > > > > > > > > > own KIP yet, but one alternative I've pitched to a
> > few
> > > > > people
> > > > > > > > with
> > > > > > > > > > > > > generally positive interest has been to develop an
> > > > official
> > > > > > > > > > > compatibility
> > > > > > > > > > > > > library for Connect developers. This library would
> be
> > > > > > released
> > > > > > > as
> > > > > > > > > its
> > > > > > > > > > > own
> > > > > > > > > > > > > Maven artifact (separate from connect-api,
> > > > connect-runtime,
> > > > > > > etc.)
> > > > > > > > > and
> > > > > > > > > > > > would
> > > > > > > > > > > > > provide a simple, clean interface for developers to
> > > > > determine
> > > > > > > > which
> > > > > > > > > > > > > features are supported by the version of the
> Connect
> > > > > runtime
> > > > > > > that
> > > > > > > > > > their
> > > > > > > > > > > > > plugin has been deployed onto. Under the hood, this
> > > > library
> > > > > > > might
> > > > > > > > > use
> > > > > > > > > > > > > reflection to determine whether classes, methods,
> > etc.
> > > > are
> > > > > > > > > available,
> > > > > > > > > > > but
> > > > > > > > > > > > > the developer wouldn't have to do anything more
> than
> > > > check
> > > > > > (for
> > > > > > > > > > > example)
> > > > > > > > > > > > >
> `Features.SINK_TASK_ERRANT_RECORD_REPORTER.enabled()`
> > > to
> > > > > know
> > > > > > > at
> > > > > > > > > any
> > > > > > > > > > > > point
> > > > > > > > > > > > > in the lifetime of their connector/task whether
> that
> > > > > feature
> > > > > > is
> > > > > > > > > > > provided
> > > > > > > > > > > > by
> > > > > > > > > > > > > the runtime.
> > > > > > > > > > > > >
> > > > > > > > > > > > > One other high-level comment: this doesn't address
> > > every
> > > > > > case,
> > > > > > > > but
> > > > > > > > > we
> > > > > > > > > > > > might
> > > > > > > > > > > > > consider adding an API to "ack" sink records. This
> > > could
> > > > > use
> > > > > > > the
> > > > > > > > > > > > > SubmittedRecords class [1] (with some slight
> tweaks)
> > > > under
> > > > > > the
> > > > > > > > hood
> > > > > > > > > > to
> > > > > > > > > > > > > track the latest-acked offset for each topic
> > partition.
> > > > > This
> > > > > > > way,
> > > > > > > > > > > > connector
> > > > > > > > > > > > > developers won't be responsible for tracking
> offsets
> > at
> > > > all
> > > > > > in
> > > > > > > > > their
> > > > > > > > > > > sink
> > > > > > > > > > > > > tasks (eliminating issues with the accuracy of
> > > > > > > > post-transformation
> > > > > > > > > > > T/P/O
> > > > > > > > > > > > > sink record information), and they'll only have to
> > > notify
> > > > > the
> > > > > > > > > Connect
> > > > > > > > > > > > > framework when a record has been successfully
> > > dispatched
> > > > to
> > > > > > the
> > > > > > > > > > > external
> > > > > > > > > > > > > system. This provides a cleaner, friendlier API,
> and
> > > also
> > > > > > > enables
> > > > > > > > > > more
> > > > > > > > > > > > > fine-grained metrics like the ones proposed in
> > KIP-767
> > > > [2].
> > > > > > > > > > > > >
> > > > > > > > > > > > > [1] -
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://github.com/apache/kafka/blob/9ab140d5419d735baae45aff56ffce7f5622744f/connect/runtime/src/main/java/org/apache/kafka/connect/runtime/SubmittedRecords.java
> > > > > > > > > > > > > [2] -
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-767%3A+Connect+Latency+Metrics
> > > > > > > > > > > > >
> > > > > > > > > > > > > Cheers,
> > > > > > > > > > > > >
> > > > > > > > > > > > > Chris
> > > > > > > > > > > > >
> > > > > > > > > > > > > On Tue, Nov 1, 2022 at 11:21 AM Yash Mayya <
> > > > > > > yash.mayya@gmail.com
> > > > > > > > >
> > > > > > > > > > > wrote:
> > > > > > > > > > > > >
> > > > > > > > > > > > > > Hi Randall,
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > It's been a while for this one but the more I
> think
> > > > about
> > > > > > it,
> > > > > > > > the
> > > > > > > > > > > more
> > > > > > > > > > > > I
> > > > > > > > > > > > > > feel like the current approach with a new
> > overloaded
> > > > > > > > > > `SinkTask::put`
> > > > > > > > > > > > > method
> > > > > > > > > > > > > > might not be optimal. We're trying to fix a
> pretty
> > > > corner
> > > > > > > case
> > > > > > > > > bug
> > > > > > > > > > > here
> > > > > > > > > > > > > > (usage of topic mutating SMTs with sink
> connectors
> > > that
> > > > > do
> > > > > > > > their
> > > > > > > > > > own
> > > > > > > > > > > > > offset
> > > > > > > > > > > > > > tracking) and I'm not sure that warrants a change
> > to
> > > > > such a
> > > > > > > > > central
> > > > > > > > > > > > > > interface method. The new `SinkTask::put` method
> > just
> > > > > seems
> > > > > > > > > > somewhat
> > > > > > > > > > > > odd
> > > > > > > > > > > > > > and it may not be very understandable for a new
> > > reader
> > > > -
> > > > > I
> > > > > > > > don't
> > > > > > > > > > > think
> > > > > > > > > > > > > this
> > > > > > > > > > > > > > should be the case for a public interface method.
> > > > > > > Furthermore,
> > > > > > > > > even
> > > > > > > > > > > > with
> > > > > > > > > > > > > > elaborate documentation in place, I'm not sure if
> > > it'll
> > > > > be
> > > > > > > very
> > > > > > > > > > > obvious
> > > > > > > > > > > > > to
> > > > > > > > > > > > > > most people what the purpose of having these two
> > > `put`
> > > > > > > methods
> > > > > > > > is
> > > > > > > > > > and
> > > > > > > > > > > > how
> > > > > > > > > > > > > > they should be used by sink task implementations.
> > > What
> > > > do
> > > > > > you
> > > > > > > > > > think?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > Yash
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > On Mon, Oct 10, 2022 at 9:33 PM Yash Mayya <
> > > > > > > > yash.mayya@gmail.com
> > > > > > > > > >
> > > > > > > > > > > > wrote:
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Hi Randall,
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Thanks a lot for your valuable feedback so far!
> > > I've
> > > > > > > updated
> > > > > > > > > the
> > > > > > > > > > > KIP
> > > > > > > > > > > > > > based
> > > > > > > > > > > > > > > on our discussion above. Could you please take
> > > > another
> > > > > > > look?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > Yash
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > On Tue, Oct 4, 2022 at 12:40 AM Randall Hauch <
> > > > > > > > > rhauch@gmail.com>
> > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >> On Mon, Oct 3, 2022 at 11:45 AM Yash Mayya <
> > > > > > > > > > yash.mayya@gmail.com>
> > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >> > Hi Randall,
> > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > >> > Thanks for elaborating. I think these are
> all
> > > very
> > > > > > good
> > > > > > > > > points
> > > > > > > > > > > > and I
> > > > > > > > > > > > > > see
> > > > > > > > > > > > > > >> > why the overloaded `SinkTask::put` method
> is a
> > > > > cleaner
> > > > > > > > > > solution
> > > > > > > > > > > > > > overall.
> > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > >> > > public void put(Collection<SinkRecord>
> > > records,
> > > > > > > > > > > Map<SinkRecord,
> > > > > > > > > > > > > > >> > TopicPartition> updatedTopicPartitions)
> > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > >> > I think this should be
> > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > >> > `public void put(Collection<SinkRecord>
> > records,
> > > > > > > > > > Map<SinkRecord,
> > > > > > > > > > > > > > >> > TopicPartition> originalTopicPartitions)`
> > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > >> > instead because the sink records themselves
> > have
> > > > the
> > > > > > > > updated
> > > > > > > > > > > topic
> > > > > > > > > > > > > > >> > partitions (i.e. after all transformations
> > have
> > > > been
> > > > > > > > > applied)
> > > > > > > > > > > and
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > >> KIP
> > > > > > > > > > > > > > >> > is proposing a way for the tasks to be able
> to
> > > > > access
> > > > > > > the
> > > > > > > > > > > original
> > > > > > > > > > > > > > topic
> > > > > > > > > > > > > > >> > partition (i.e. before transformations have
> > been
> > > > > > > applied).
> > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >> Sounds good.
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > >> > > Of course, if the developer does not need
> > > > separate
> > > > > > > > > methods,
> > > > > > > > > > > they
> > > > > > > > > > > > > can
> > > > > > > > > > > > > > >> > easily have the older `put` method simply
> > > delegate
> > > > > to
> > > > > > > the
> > > > > > > > > > newer
> > > > > > > > > > > > > > method.
> > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > >> > If the developer does not need separate
> > methods
> > > > > (i.e.
> > > > > > > they
> > > > > > > > > > don't
> > > > > > > > > > > > > need
> > > > > > > > > > > > > > to
> > > > > > > > > > > > > > >> > use this new addition), they can simply
> > continue
> > > > > > > > > implementing
> > > > > > > > > > > just
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > >> > older `put` method right?
> > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >> Correct. We should update the JavaDoc of both
> > > > methods
> > > > > to
> > > > > > > > make
> > > > > > > > > > this
> > > > > > > > > > > > > > clear,
> > > > > > > > > > > > > > >> and in general how the two methods should are
> > used
> > > > and
> > > > > > > > should
> > > > > > > > > be
> > > > > > > > > > > > > > >> implemented. That can be part of the PR, and
> the
> > > KIP
> > > > > > > doesn't
> > > > > > > > > > need
> > > > > > > > > > > > this
> > > > > > > > > > > > > > >> wording.
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > >> > > Finally, this gives us a roadmap for
> > > > *eventually*
> > > > > > > > > > deprecating
> > > > > > > > > > > > the
> > > > > > > > > > > > > > >> older
> > > > > > > > > > > > > > >> > method, once the Connect runtime versions
> > > without
> > > > > this
> > > > > > > > > change
> > > > > > > > > > > are
> > > > > > > > > > > > > old
> > > > > > > > > > > > > > >> > enough.
> > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > >> > I'm not sure we'd ever want to deprecate the
> > > older
> > > > > > > method.
> > > > > > > > > > Most
> > > > > > > > > > > > > common
> > > > > > > > > > > > > > >> sink
> > > > > > > > > > > > > > >> > connector implementations do not do their
> own
> > > > offset
> > > > > > > > > tracking
> > > > > > > > > > > with
> > > > > > > > > > > > > > >> > asynchronous processing and will probably
> > never
> > > > > have a
> > > > > > > > need
> > > > > > > > > > for
> > > > > > > > > > > > the
> > > > > > > > > > > > > > >> > additional parameter `Map<SinkRecord,
> > > > > TopicPartition>
> > > > > > > > > > > > > > >> > originalTopicPartitions` in the proposed new
> > > `put`
> > > > > > > method.
> > > > > > > > > > These
> > > > > > > > > > > > > > >> connectors
> > > > > > > > > > > > > > >> > can continue implementing only the existing
> > > > > > > > `SinkTask::put`
> > > > > > > > > > > method
> > > > > > > > > > > > > > which
> > > > > > > > > > > > > > >> > will be called by the default implementation
> > of
> > > > the
> > > > > > > newer
> > > > > > > > > > > > overloaded
> > > > > > > > > > > > > > >> `put`
> > > > > > > > > > > > > > >> > method.
> > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >> +1
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > >> > > the pre-commit methods use the same
> > > > > > > `Map<TopicPartition,
> > > > > > > > > > > > > > >> > OffsetAndMetadata> currentOffsets` data
> > > structure
> > > > > I'm
> > > > > > > > > > suggesting
> > > > > > > > > > > > be
> > > > > > > > > > > > > > >> used.
> > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > >> > The data structure you're suggesting be used
> > is
> > > a
> > > > > > > > > > > `Map<SinkRecord,
> > > > > > > > > > > > > > >> > TopicPartition>` which will map `SinkRecord`
> > > > objects
> > > > > > to
> > > > > > > > the
> > > > > > > > > > > > original
> > > > > > > > > > > > > > >> topic
> > > > > > > > > > > > > > >> > partition of the corresponding
> > `ConsumerRecord`
> > > > > right?
> > > > > > > To
> > > > > > > > > > > clarify,
> > > > > > > > > > > > > > this
> > > > > > > > > > > > > > >> is
> > > > > > > > > > > > > > >> > a new data structure that will need to be
> > > managed
> > > > in
> > > > > > the
> > > > > > > > > > > > > > >> `WorkerSinkTask`.
> > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >> Ah, you're right. Thanks for the correction.
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >> Best regards,
> > > > > > > > > > > > > > >> Randall
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >> > Thanks,
> > > > > > > > > > > > > > >> > Yash
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >> > On Mon, Oct 3, 2022 at 1:20 AM Randall
> Hauch <
> > > > > > > > > > rhauch@gmail.com>
> > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > >> > > Hi, Yash.
> > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > >> > > I'm not sure I quite understand why it
> would
> > > be
> > > > > > > "easier"
> > > > > > > > > for
> > > > > > > > > > > > > > connector
> > > > > > > > > > > > > > >> > > > developers to account for implementing
> two
> > > > > > different
> > > > > > > > > > > > overloaded
> > > > > > > > > > > > > > >> `put`
> > > > > > > > > > > > > > >> > > > methods (assuming that they want to use
> > this
> > > > new
> > > > > > > > > feature)
> > > > > > > > > > > > versus
> > > > > > > > > > > > > > >> using
> > > > > > > > > > > > > > >> > a
> > > > > > > > > > > > > > >> > > > try-catch block around `SinkRecord`
> access
> > > > > > methods?
> > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > >> > > Using a try-catch to try around an API
> > method
> > > > that
> > > > > > > > *might*
> > > > > > > > > > be
> > > > > > > > > > > > > there
> > > > > > > > > > > > > > >> is a
> > > > > > > > > > > > > > >> > > very unusual thing for most developers.
> > > > > > Unfortunately,
> > > > > > > > > we've
> > > > > > > > > > > had
> > > > > > > > > > > > > to
> > > > > > > > > > > > > > >> > resort
> > > > > > > > > > > > > > >> > > to this atypical approach with Connect in
> > > places
> > > > > > when
> > > > > > > > > there
> > > > > > > > > > > was
> > > > > > > > > > > > no
> > > > > > > > > > > > > > >> good
> > > > > > > > > > > > > > >> > > alternative. We seem to relying upon
> pattern
> > > > > because
> > > > > > > > it's
> > > > > > > > > > > easier
> > > > > > > > > > > > > for
> > > > > > > > > > > > > > >> us,
> > > > > > > > > > > > > > >> > > not because it offers a better experience
> > for
> > > > > > > Connector
> > > > > > > > > > > > > developers.
> > > > > > > > > > > > > > >> IMO,
> > > > > > > > > > > > > > >> > if
> > > > > > > > > > > > > > >> > > there's a practical alternative that uses
> > > normal
> > > > > > > > > development
> > > > > > > > > > > > > > practices
> > > > > > > > > > > > > > >> > and
> > > > > > > > > > > > > > >> > > techniques, then we should use that
> > > alternative.
> > > > > > IIUC,
> > > > > > > > > there
> > > > > > > > > > > is
> > > > > > > > > > > > at
> > > > > > > > > > > > > > >> least
> > > > > > > > > > > > > > >> > > one practical alternative for this KIP
> that
> > > > would
> > > > > > not
> > > > > > > > > > require
> > > > > > > > > > > > > > >> developers
> > > > > > > > > > > > > > >> > to
> > > > > > > > > > > > > > >> > > use the unusual try-catch to handle the
> case
> > > > where
> > > > > > > > methods
> > > > > > > > > > are
> > > > > > > > > > > > not
> > > > > > > > > > > > > > >> found.
> > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > >> > > I also think having two `put` methods is
> > > easier
> > > > > when
> > > > > > > the
> > > > > > > > > > > > Connector
> > > > > > > > > > > > > > >> has to
> > > > > > > > > > > > > > >> > > do different things for different Connect
> > > > > runtimes,
> > > > > > > too.
> > > > > > > > > One
> > > > > > > > > > > of
> > > > > > > > > > > > > > those
> > > > > > > > > > > > > > >> > > methods is called by newer Connect
> runtimes
> > > with
> > > > > the
> > > > > > > new
> > > > > > > > > > > > behavior,
> > > > > > > > > > > > > > and
> > > > > > > > > > > > > > >> > the
> > > > > > > > > > > > > > >> > > other method is called by an older Connect
> > > > > runtime.
> > > > > > Of
> > > > > > > > > > course,
> > > > > > > > > > > > if
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > >> > > developer does not need separate methods,
> > they
> > > > can
> > > > > > > > easily
> > > > > > > > > > have
> > > > > > > > > > > > the
> > > > > > > > > > > > > > >> older
> > > > > > > > > > > > > > >> > > `put` method simply delegate to the newer
> > > > method.
> > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > >> > > Finally, this gives us a roadmap for
> > > > *eventually*
> > > > > > > > > > deprecating
> > > > > > > > > > > > the
> > > > > > > > > > > > > > >> older
> > > > > > > > > > > > > > >> > > method, once the Connect runtime versions
> > > > without
> > > > > > this
> > > > > > > > > > change
> > > > > > > > > > > > are
> > > > > > > > > > > > > > old
> > > > > > > > > > > > > > >> > > enough.
> > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > >> > > I think the advantage of going with the
> > > > > > > > > > > > > > >> > > > proposed approach in the KIP is that it
> > > > wouldn't
> > > > > > > > require
> > > > > > > > > > > extra
> > > > > > > > > > > > > > >> > > book-keeping
> > > > > > > > > > > > > > >> > > > (the Map<SinkRecord,
> > > > > > > > > > > > > > >> > > > TopicPartition> in `WorkerSinkTask` in
> > your
> > > > > > proposed
> > > > > > > > > > > approach)
> > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > >> > > The connector does have to do some of this
> > > > > > bookkeeping
> > > > > > > > in
> > > > > > > > > > how
> > > > > > > > > > > > they
> > > > > > > > > > > > > > >> track
> > > > > > > > > > > > > > >> > > the topic partition offsets used in the
> > > > > `preCommit`,
> > > > > > > and
> > > > > > > > > the
> > > > > > > > > > > > > > >> pre-commit
> > > > > > > > > > > > > > >> > > methods use the same `Map<TopicPartition,
> > > > > > > > > OffsetAndMetadata>
> > > > > > > > > > > > > > >> > > currentOffsets`
> > > > > > > > > > > > > > >> > > data structure I'm suggesting be used.
> > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > >> > > I hope that helps.
> > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > >> > > Best regards,
> > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > >> > > Randall
> > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > >> > > On Mon, Sep 26, 2022 at 9:38 AM Yash
> Mayya <
> > > > > > > > > > > > yash.mayya@gmail.com>
> > > > > > > > > > > > > > >> wrote:
> > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > >> > > > Hi Randall,
> > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > >> > > > Thanks for reviewing the KIP!
> > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > >> > > > > That latter logic can get quite ugly.
> > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > >> > > > I'm not sure I quite understand why it
> > would
> > > > be
> > > > > > > > "easier"
> > > > > > > > > > for
> > > > > > > > > > > > > > >> connector
> > > > > > > > > > > > > > >> > > > developers to account for implementing
> two
> > > > > > different
> > > > > > > > > > > > overloaded
> > > > > > > > > > > > > > >> `put`
> > > > > > > > > > > > > > >> > > > methods (assuming that they want to use
> > this
> > > > new
> > > > > > > > > feature)
> > > > > > > > > > > > versus
> > > > > > > > > > > > > > >> using
> > > > > > > > > > > > > > >> > a
> > > > > > > > > > > > > > >> > > > try-catch block around `SinkRecord`
> access
> > > > > > methods?
> > > > > > > In
> > > > > > > > > > both
> > > > > > > > > > > > > > cases, a
> > > > > > > > > > > > > > >> > > > connector developer would need to write
> > > > > additional
> > > > > > > > code
> > > > > > > > > in
> > > > > > > > > > > > order
> > > > > > > > > > > > > > to
> > > > > > > > > > > > > > >> > > ensure
> > > > > > > > > > > > > > >> > > > that their connector continues working
> > with
> > > > > older
> > > > > > > > > Connect
> > > > > > > > > > > > > > runtimes.
> > > > > > > > > > > > > > >> > > > Furthermore, we would probably need to
> > > > carefully
> > > > > > > > > document
> > > > > > > > > > > how
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > >> > > > implementation for the older `put`
> method
> > > > should
> > > > > > > look
> > > > > > > > > like
> > > > > > > > > > > for
> > > > > > > > > > > > > > >> > connectors
> > > > > > > > > > > > > > >> > > > that want to use this new feature. I
> think
> > > the
> > > > > > > > advantage
> > > > > > > > > > of
> > > > > > > > > > > > > going
> > > > > > > > > > > > > > >> with
> > > > > > > > > > > > > > >> > > the
> > > > > > > > > > > > > > >> > > > proposed approach in the KIP is that it
> > > > wouldn't
> > > > > > > > require
> > > > > > > > > > > extra
> > > > > > > > > > > > > > >> > > book-keeping
> > > > > > > > > > > > > > >> > > > (the Map<SinkRecord,
> > > > > > > > > > > > > > >> > > > TopicPartition> in `WorkerSinkTask` in
> > your
> > > > > > proposed
> > > > > > > > > > > approach)
> > > > > > > > > > > > > and
> > > > > > > > > > > > > > >> also
> > > > > > > > > > > > > > >> > > the
> > > > > > > > > > > > > > >> > > > fact that the try-catch based logic is
> an
> > > > > already
> > > > > > > > > > > established
> > > > > > > > > > > > > > >> pattern
> > > > > > > > > > > > > > >> > > > through
> > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-610%3A+Error+Reporting+in+Sink+Connectors
> > > > > > > > > > > > > > >> > > > and other KIPs which added methods to
> > > > > source/sink
> > > > > > > > > > > > connector/task
> > > > > > > > > > > > > > >> > > contexts.
> > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > >> > > > Let me know if you still feel that
> having
> > a
> > > > new
> > > > > > > > > overloaded
> > > > > > > > > > > put
> > > > > > > > > > > > > > >> method
> > > > > > > > > > > > > > >> > is
> > > > > > > > > > > > > > >> > > a
> > > > > > > > > > > > > > >> > > > cleaner solution and I'd be happy to
> > > > reconsider!
> > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > >> > > > Thanks,
> > > > > > > > > > > > > > >> > > > Yash
> > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > >> > > > On Thu, Sep 22, 2022 at 11:18 PM Randall
> > > > Hauch <
> > > > > > > > > > > > > rhauch@gmail.com>
> > > > > > > > > > > > > > >> > wrote:
> > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > >> > > > > Hi, Yash. Thanks for picking up this
> KIP
> > > and
> > > > > > > > > discussion.
> > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > >> > > > > The KIP includes this rejected
> > > alternative:
> > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > >> > > > > > 4. Update SinkTask.put in any way to
> > > pass
> > > > > the
> > > > > > > new
> > > > > > > > > > > > > information
> > > > > > > > > > > > > > >> > outside
> > > > > > > > > > > > > > >> > > > > > SinkRecord (e.g. a Map or a derived
> > > class)
> > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > >> > > > > >    -
> > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > >> > > > > >    Much more disruptive change
> without
> > > > > > > > considerable
> > > > > > > > > > pros
> > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > >> > > > > One advantage about doing this is that
> > > sink
> > > > > > > > connector
> > > > > > > > > > > > > > >> implementations
> > > > > > > > > > > > > > >> > > can
> > > > > > > > > > > > > > >> > > > > more easily implement two different
> > > > "put(...)"
> > > > > > > > methods
> > > > > > > > > > to
> > > > > > > > > > > > > handle
> > > > > > > > > > > > > > >> > > running
> > > > > > > > > > > > > > >> > > > in
> > > > > > > > > > > > > > >> > > > > a variety of runtimes, without having
> to
> > > use
> > > > > > > > try-catch
> > > > > > > > > > > logic
> > > > > > > > > > > > > > >> around
> > > > > > > > > > > > > > >> > the
> > > > > > > > > > > > > > >> > > > > newer SinkRecord access methods. That
> > > latter
> > > > > > logic
> > > > > > > > can
> > > > > > > > > > get
> > > > > > > > > > > > > quite
> > > > > > > > > > > > > > >> > ugly.
> > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > >> > > > > For example, the existing `put` method
> > has
> > > > > this
> > > > > > > > > > signature:
> > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > >> > > > > public abstract void
> > > > > put(Collection<SinkRecord>
> > > > > > > > > > records);
> > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > >> > > > > If we added an overloaded method that
> > > passed
> > > > > in
> > > > > > a
> > > > > > > > map
> > > > > > > > > of
> > > > > > > > > > > the
> > > > > > > > > > > > > old
> > > > > > > > > > > > > > >> > > > > topic+partition for each record (and
> > > defined
> > > > > the
> > > > > > > > > absence
> > > > > > > > > > > of
> > > > > > > > > > > > an
> > > > > > > > > > > > > > >> entry
> > > > > > > > > > > > > > >> > as
> > > > > > > > > > > > > > >> > > > > having an unchanged topic and
> > partition):
> > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > >> > > > > public void put(Collection<SinkRecord>
> > > > > records,
> > > > > > > > > > > > > Map<SinkRecord,
> > > > > > > > > > > > > > >> > > > > TopicPartition>
> updatedTopicPartitions)
> > {
> > > > > > > > > > > > > > >> > > > > put(records);
> > > > > > > > > > > > > > >> > > > > }
> > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > >> > > > > then a `SinkTask` implementation that
> > > wants
> > > > to
> > > > > > use
> > > > > > > > > this
> > > > > > > > > > > new
> > > > > > > > > > > > > > >> feature
> > > > > > > > > > > > > > >> > > could
> > > > > > > > > > > > > > >> > > > > simply implement both methods:
> > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > >> > > > > public void put(Collection<SinkRecord>
> > > > > records)
> > > > > > {
> > > > > > > > > > > > > > >> > > > > // Running in an older runtime, so no
> > > > tracking
> > > > > > of
> > > > > > > > > > > > SMT-modified
> > > > > > > > > > > > > > >> topic
> > > > > > > > > > > > > > >> > > > names
> > > > > > > > > > > > > > >> > > > > or partitions
> > > > > > > > > > > > > > >> > > > > put(records, Map.of());
> > > > > > > > > > > > > > >> > > > > }
> > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > >> > > > > public void put(Collection<SinkRecord>
> > > > > records,
> > > > > > > > > > > > > Map<SinkRecord,
> > > > > > > > > > > > > > >> > > > > TopicPartition>
> updatedTopicPartitions)
> > {
> > > > > > > > > > > > > > >> > > > > // real logic here
> > > > > > > > > > > > > > >> > > > > }
> > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > >> > > > > This seems a lot easier than having to
> > use
> > > > > > > try-catch
> > > > > > > > > > > logic,
> > > > > > > > > > > > > yet
> > > > > > > > > > > > > > >> still
> > > > > > > > > > > > > > >> > > > > allows sink connectors to utilize the
> > new
> > > > > > > > > functionality
> > > > > > > > > > > and
> > > > > > > > > > > > > > still
> > > > > > > > > > > > > > >> > work
> > > > > > > > > > > > > > >> > > > with
> > > > > > > > > > > > > > >> > > > > older Connect runtimes.
> > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > >> > > > > WDYT?
> > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > >> > > > > Randall
> > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > >> > > > > On Thu, Sep 8, 2022 at 7:03 AM Yash
> > Mayya
> > > <
> > > > > > > > > > > > > yash.mayya@gmail.com
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >> > > wrote:
> > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > >> > > > > > Hi all,
> > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > >> > > > > > I would like to (re)start a new
> > > discussion
> > > > > > > thread
> > > > > > > > on
> > > > > > > > > > > > KIP-793
> > > > > > > > > > > > > > >> (Kafka
> > > > > > > > > > > > > > >> > > > > > Connect) which proposes some
> additions
> > > to
> > > > > the
> > > > > > > > public
> > > > > > > > > > > > > > SinkRecord
> > > > > > > > > > > > > > >> > > > interface
> > > > > > > > > > > > > > >> > > > > > in order to support topic mutating
> > SMTs
> > > > for
> > > > > > sink
> > > > > > > > > > > > connectors
> > > > > > > > > > > > > > >> that do
> > > > > > > > > > > > > > >> > > > their
> > > > > > > > > > > > > > >> > > > > > own offset tracking.
> > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > >> > > > > > Links:
> > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > >> > > > > > KIP:
> > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=191336830
> > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > >> > > > > > Older discussion thread:
> > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > >>
> > > > > > > > > >
> > > > https://lists.apache.org/thread/00kcth6057jdcsyzgy1x8nb2s1cymy8h
> > > > > ,
> > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > >>
> > > > > > > > > >
> > > > https://lists.apache.org/thread/rzqkm0q5y5v3vdjhg8wqppxbkw7nyopj
> > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > >> > > > > > Jira:
> > > > > > > > > > https://issues.apache.org/jira/browse/KAFKA-13431
> > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > >> > > > > > Thanks,
> > > > > > > > > > > > > > >> > > > > > Yash
> > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
>

Re: [DISCUSS] KIP-793: Sink Connectors: Support topic-mutating SMTs for async connectors (preCommit users)

[Yash Mayya <ya...@gmail.com>]

Hi Chris,

Thanks for pointing that out, I hadn't realized that the SubmittedRecords
class has almost exactly the same semantics needed for handling offset
commits in the per-sink record ack API case. However, I agree that it isn't
worth the tradeoff and we've already discussed the backward compatibility
concerns imposed on connector developers if we were to consider deprecating
/ removing the preCommit hook in favor of a new ack-based API.

Thanks,
Yash

On Thu, Jun 29, 2023 at 7:31 PM Chris Egerton <ch...@aiven.io.invalid>
wrote:

> Hi Yash,
>
> Thanks for your continued work on this tricky feature. I have no further
> comments or suggestions on the KIP and am ready to vote in favor of it.
>
> That said, I did want to quickly respond to this comment:
>
> > On a side note, this also means that the per sink record ack API
> that was proposed earlier wouldn't really work for this case since Kafka
> consumers themselves don't support per message acknowledgement semantics
> (and any sort of manual book-keeping based on offset linearity in a topic
> partition would be affected by things like log compaction, control records
> for transactional use cases etc.) right?
>
> I believe we could still use the SubmittedRecords class [1] (with some
> small tweaks) to track ack'd messages and the latest-committable offsets
> per topic partition, without relying on assumptions about offsets for
> consecutive records consumed from Kafka always differing by one. But at
> this point I think that, although this approach does come with the
> advantage of also enabling fine-grained metrics on record delivery to the
> sink system, it's not worth the tradeoff in intuition since it's less clear
> why users should prefer that API instead of using SinkTask::preCommit.
>
> [1] -
>
> https://github.com/apache/kafka/blob/12be344fdd3b20f338ccab87933b89049ce202a4/connect/runtime/src/main/java/org/apache/kafka/connect/runtime/SubmittedRecords.java
>
> Cheers,
>
> Chris
>
> On Wed, Jun 21, 2023 at 9:46 AM Yash Mayya <ya...@gmail.com> wrote:
>
> > Hi Chris,
> >
> > Firstly, thanks for sharing your detailed thoughts on this thorny issue!
> > Point taken on Kafka Connect being a brownfield project and I guess we
> > might just need to trade off elegant / "clean" interfaces for fixing this
> > gap in functionality. Also, thanks for calling out all the existing
> > cross-plugin interactions and also the fact that connectors are not and
> > should not be developed in silos ignoring the rest of the ecosystem. That
> > said, here are my thoughts:
> >
> > > we could replace these methods with headers that the
> > > Connect runtime automatically injects into records directly
> > > before dispatching them to SinkTask::put.
> >
> > Hm, that's an interesting idea to get around the need for connectors to
> > handle potential 'NoSuchMethodError's in calls to
> > SinkRecord::originalTopic/originalKafkaPartition/originalKafkaOffset.
> > However, I'm inclined to agree that retrieving these values from the
> record
> > headers seems even less intuitive and I'm okay with adding this to the
> > rejected alternatives list.
> >
> > > we can consider eliminating the overridden
> > > SinkTask::open/close methods
> >
> > I tried to further explore the idea of keeping just the existing
> > SinkTask::open / SinkTask::close methods but only calling them with
> > post-transform topic partitions and ended up coming to the same
> conclusion
> > that you did earlier in this thread :)
> >
> > The overloaded SinkTask::open / SinkTask::close are currently the biggest
> > sticking points with the latest iteration of this KIP and I'd prefer this
> > elimination for now. The primary reasoning is that the information from
> > open / close on pre-transform topic partitions can be combined with the
> per
> > record information of both pre-transform and post-transform topic
> > partitions to handle most practical use cases without significantly
> > muddying the sink connector related public interfaces. The argument that
> > this makes it harder for sink connectors to deal with post-transform
> topic
> > partitions (i.e. in terms of grouping together or batching records for
> > writing to the sink system) can be countered with the fact that it'll be
> > similarly challenging even with the overloaded method approach of calling
> > open / close with both pre-transform and post-transform topic partitions
> > since the batching would be done on post-transform topic partitions
> whereas
> > offset tracking and reporting for commits would be done on pre-transform
> > topic partitions (and the two won't necessarily serially advance in
> > lockstep). On a side note, this also means that the per sink record ack
> API
> > that was proposed earlier wouldn't really work for this case since Kafka
> > consumers themselves don't support per message acknowledgement semantics
> > (and any sort of manual book-keeping based on offset linearity in a topic
> > partition would be affected by things like log compaction, control
> records
> > for transactional use cases etc.) right? Overall, I think that the only
> > benefit of the overloaded open / close methods approach is that the
> > framework can enable the eventual closure of any post-transform topic
> > partition based writers created by sink tasks using the heuristics we
> > discussed earlier (via a cache with a time-based eviction policy) which
> > doesn't seem worth it at this point.
> >
> > Thanks,
> > Yash
> >
> > On Mon, May 22, 2023 at 7:30 PM Chris Egerton <ch...@aiven.io.invalid>
> > wrote:
> >
> > > Hi Yash,
> > >
> > > I've been following the discussion and have some thoughts. Ultimately
> I'm
> > > still in favor of this KIP and would hate to see it go dormant, though
> we
> > > may end up settling for a less-invasive option.
> > >
> > >
> > > On the topic of abstraction and inter-plugin interactions:
> > >
> > > First, there already are instances of cross-plugin interactions.
> Logical
> > > type handling is probably the biggest example: a source connector
> embeds
> > > metadata in the schema for record keys/values it emits that notifies
> > > downstream converters about how to handle them. We provide support for
> > some
> > > logical types in Connect out of the box, but there's nothing stopping
> > > connector and converter developers from implementing their own logical
> > type
> > > support using the exact same mechanism and different logical type
> names,
> > > which is already done by Debezium, to name one example.
> > >
> > > Second, although it's been a goal of Connect to abstract away parts of
> > > building a data pipeline so that, e.g., connector developers don't have
> > to
> > > be concerned with converters or consumers, in reality, this layer of
> > > abstraction has already been eroded. The example that most-readily
> comes
> > to
> > > mind is how source tasks are notified of the offsets of records that
> > > they've emitted after they've been published to Kafka via
> > > SourceTask::commitRecord [1].
> > >
> > > But, more importantly, it's unlikely that connectors are being
> developed
> > in
> > > complete isolation. Nobody's going to implement the SinkConnector /
> > > SinkTask interfaces and then throw that code off to someone else to
> > figure
> > > out all the details of deployment, configuration, testing, etc.
> > Developers
> > > will probably have to be aware of at least the converter interface,
> some
> > of
> > > the available implementations of it, and some details of Kafka clients
> > > (e.g., consumer groups for sink connectors). And this isn't a bad
> > > thing--it's unlikely that someone will write a Kafka connector without
> > > having or benefitting from some understanding of Kafka and the steps of
> > the
> > > data pipeline that it will be a part of.
> > >
> > > Bringing this to the practical topic of discussion--transformations--I
> > > think it's actually in everyone's best interests for connector
> developers
> > > to be aware of transformations. This isn't just because of the specific
> > > problem that the KIP is trying to address. It's because there's plenty
> of
> > > logic that can be implemented via SMT that a naive connector developer
> > will
> > > think that they have to implement on their own, which will ultimately
> > lead
> > > to a sub-par experience for people who end up using those connectors
> due
> > to
> > > inconsistent semantics (especially lack of predicates), inconsistent
> > > configuration syntax, increased chances for bugs, and FUD ("why wasn't
> > this
> > > implemented as an SMT?").
> > >
> > > Finally, although preserving clean, composable interfaces that can be
> > > understood in isolation is a great principle to start with, we are now
> in
> > > what Anna McDonald recently referred to as "brownfield" space for
> > Connect.
> > > We can't go back in time and redesign the SMT interface/contracts to
> make
> > > things cleaner. And I don't think it's fair to anyone to suddenly drop
> > > support for SMTs that mutate t/p/o information for sink records,
> > especially
> > > since these can be used gainfully with plenty of existing sink
> > connectors.
> > >
> > > Ultimately I still think the path forward that's best for the users is
> to
> > > make the impossible possible by addressing this long-standing API gap
> in
> > > Connect. Yes, it adds to the cognitive burden for connector developers,
> > but
> > > if they can tolerate it, the end result is better for everyone
> involved,
> > > and if they can't, it's likely that the end result will be a
> preservation
> > > of existing behavior, which leaves us no worse than before.
> > >
> > >
> > > With all that said, I've thought about how to minimize or at least hide
> > the
> > > API changes as much as possible. I've had two thoughts:
> > >
> > > 1. On the
> > > SinkRecord::originalTopic/originalKafkaPartition/originalKafkaOffset
> > front,
> > > we could replace these methods with headers that the Connect runtime
> > > automatically injects into records directly before dispatching them to
> > > SinkTask::put. The names can be the proposed method names (e.g.,
> > > "originalTopic"). I believe this is inferior to the current proposal
> and
> > > should be a rejected alternative, but it at least seemed worth floating
> > in
> > > the name of compromise. I dislike this approach for two reasons: first,
> > it
> > > seems even less intuitive, and second, it doesn't come with the benefit
> > of
> > > encouraging connector developers to understand the SMT interface and
> take
> > > it into account when designing connectors.
> > >
> > > 2. Although I'd hate to see the same bookkeeping logic implemented in
> > > multiple connectors, we can consider eliminating the overridden
> > > SinkTask::open/close methods. A note should be added to both methods
> > > clarifying that they are only invoked with the original, pre-transform
> > > topic partitions, and developers will be on their own if they want to
> > deal
> > > with post-transform topic partitions instead. I'm on the fence with
> this
> > > one, but if it's a choice between passing this KIP without modifying
> > > SinkTask::open/close, or letting the KIP go dormant, I'd happily choose
> > the
> > > former.
> > >
> > > Thanks Yash and Greg for the discussion so far, and apologies for the
> > wall
> > > of text. Looking forward to your thoughts.
> > >
> > > Cheers,
> > >
> > > Chris
> > >
> > > [1] -
> > >
> > >
> >
> https://kafka.apache.org/34/javadoc/org/apache/kafka/connect/source/SourceTask.html#commitRecord(org.apache.kafka.connect.source.SourceRecord,org.apache.kafka.clients.producer.RecordMetadata)
> > >
> > > On Sun, Apr 23, 2023 at 11:20 AM Yash Mayya <ya...@gmail.com>
> > wrote:
> > >
> > > > Hi Greg,
> > > >
> > > > Thanks for the response and sorry for the late reply.
> > > >
> > > > > Currently the AK tests have a lot of calls to, for example, new
> > > > > SinkRecord(String topic, int partition, Schema keySchema,
> > > > > Object key, Schema valueSchema, Object value, long kafkaOffset)
> > > > > , a constructor without the original T/P/O values. I assumed that
> for
> > > > > backwards compatibility these constructors would still be usable in
> > > > > new runtimes. I imagine that there are also tests in downstream
> > > projects
> > > > > which make use of these constructors, whenever a Transform,
> > Predicate,
> > > > > or Task is tested without a corresponding Converter. My question
> was
> > > > > about what values are chosen for the original T/P/O methods when
> > these
> > > > > constructors are used after an upgrade to the latest connect-api.
> > > >
> > > > That's a good question - since this should only primarily affect
> > testing
> > > I
> > > > think it should be acceptable to simply use the topic, partition and
> > > > kafkaOffset values as the originalTopic, originalKafkaPartition
> > > > and originalKafkaOffset?
> > > >
> > > > > If you inject the original T/P/O only before and after the chain,
> > SMTs
> > > > > after an SMT which changes the original T/P/O will see whatever the
> > > > earlier
> > > > > SMT emitted. Is this intentional, or should this be avoided?
> > > >
> > > > Hmm, this sounds like a misbehaving / badly implemented SMTs since
> > there
> > > > doesn't seem to be any reasonable situation where an SMT should
> modify
> > a
> > > > sink record's original topic / partition / offset data so I'm not in
> > > favor
> > > > of introducing checks and guards in the framework for this.
> > > >
> > > > Another point that I've been pondering about is the one you raised
> > about
> > > > the composability of Connect's plugin ecosystem and the special case
> > > > handling we're adding to sink connector plugins to work with certain
> > > > transformation plugin types. This really doesn't seem like a good
> > > precedent
> > > > to be setting / starting (since there don't seem to be any other such
> > > > "snowflake" inter-plugin interactions) in my opinion. The alternative
> > of
> > > > completely managing this in the framework (and only exposing the
> > virtual
> > > > coordinates to the sink tasks) doesn't seem too appealing either due
> to
> > > the
> > > > backward compatibility concerns while maintaining existing support
> and
> > > > functionality such as the possibility of implementing exactly-once
> > > > semantics, ability for tasks to rewind consumer offsets arbitrarily
> > > (which
> > > > might require the introduction of some form of persistence for the
> > > physical
> > > > <-> virtual coordinate mapping) etc. Unfortunately, even though this
> > is a
> > > > long standing problem that all of us want to fix, I'm considering
> > moving
> > > > this KIP into a dormant / inactive state since there doesn't seem to
> > be a
> > > > design that satisfies all the general principles that the Kafka
> Connect
> > > > framework has striven to uphold.
> > > >
> > > > Thanks,
> > > > Yash
> > > >
> > > > On Tue, Mar 14, 2023 at 3:31 AM Greg Harris
> > <greg.harris@aiven.io.invalid
> > > >
> > > > wrote:
> > > >
> > > > > Yash,
> > > > >
> > > > > > 'm not sure I follow - are you asking about how the tests will be
> > > > updated
> > > > > post this change or about how upgrades will look like for clusters
> in
> > > > > production?
> > > > >
> > > > > Currently the AK tests have a lot of calls to, for example, new
> > > > > SinkRecord(String topic, int partition, Schema keySchema, Object
> key,
> > > > > Schema valueSchema, Object value, long kafkaOffset), a constructor
> > > > without
> > > > > the original T/P/O values. I assumed that for backwards
> compatibility
> > > > these
> > > > > constructors would still be usable in new runtimes.
> > > > > I imagine that there are also tests in downstream projects which
> make
> > > use
> > > > > of these constructors, whenever a Transform, Predicate, or Task is
> > > tested
> > > > > without a corresponding Converter. My question was about what
> values
> > > are
> > > > > chosen for the original T/P/O methods when these constructors are
> > used
> > > > > after an upgrade to the latest connect-api.
> > > > >
> > > > > > There shouldn't be any difference in behavior here - the
> framework
> > > will
> > > > > add
> > > > > the original T/P/O metadata to the record after the entire
> > > transformation
> > > > > chain has been applied and just before sending the record to the
> task
> > > for
> > > > > processing. The KIP doesn't propose that transformations themselves
> > > > should
> > > > > also be able to retrieve original T/P/O information for a sink
> > record.
> > > > >
> > > > > The KIP includes this: "Note that while the record's offset can't
> be
> > > > > modified via the standard SinkRecord::newRecord methods that SMTs
> are
> > > > > expected to use, SinkRecord has public constructors that would
> allow
> > > SMTs
> > > > > to return records with modified offsets. This is why the proposed
> > > changes
> > > > > include a new SinkRecord::originalKafkaOffset method as well."
> > > > > In order to use the new or old SinkRecord constructors outside of
> the
> > > > > newRecord methods, SMTs will downcast the previous record and may
> > > access
> > > > > the original T/P/O methods. They may or may not forward this to the
> > > next
> > > > > SMT, and they may or may not use it in their own computation.
> > > > > Since this is acknowledged as a possible implementation, I was just
> > > > asking
> > > > > about when one SMT changes the original T/P/O, what should later
> SMTs
> > > and
> > > > > predicates see from the original T/P/O methods?
> > > > > If you inject the original T/P/O only before and after the chain,
> > SMTs
> > > > > after an SMT which changes the original T/P/O will see whatever the
> > > > earlier
> > > > > SMT emitted. Is this intentional, or should this be avoided?
> > > > > For existing SMTs use the SinkRecord constructor, either directly
> or
> > > via
> > > > > subclasses of ConnectRecord, they will drop the original T/P/O and
> > fall
> > > > > back to the logic from question (1).
> > > > >
> > > > > > The rejected alternative basically says that we can't do a
> > > > > deterministic mapping from virtual coordinates to physical
> > coordinates
> > > > > without doing a lot of book-keeping.
> > > > >
> > > > > I suppose there is a possible implementation of metadata
> book-keeping
> > > > which
> > > > > provides a reasonable system of virtual coordinates, it just ended
> up
> > > > > equivalent to hydrating intermediate topics to compute a consistent
> > > > record
> > > > > ordering. I wasn't convinced by calling it "book-keeping" since
> i've
> > > seen
> > > > > that phrase used to disregard much less complicated state
> management,
> > > and
> > > > > had to see exactly where that solution becomes unreasonable.
> > > > >
> > > > > Thanks,
> > > > > Greg
> > > > >
> > > > > On Sun, Mar 12, 2023 at 6:30 AM Yash Mayya <ya...@gmail.com>
> > > wrote:
> > > > >
> > > > > > Hi Greg,
> > > > > >
> > > > > > Thanks for the detailed review!
> > > > > >
> > > > > > > What is the expected state/behavior for SinkRecords
> > > > > > > which do not have original T/P/O information after the
> > > > > > > upgrade? Just browsing, it appears that tests make
> > > > > > > extensive use of the existing public SinkRecord
> > > > > > > constructors  for both Transformations and Connectors.
> > > > > >
> > > > > > I'm not sure I follow - are you asking about how the tests will
> be
> > > > > updated
> > > > > > post this change or about how upgrades will look like for
> clusters
> > in
> > > > > > production? For the latter, we won't have to worry about sink
> > records
> > > > > > without original T/P/O information at all once a cluster is fully
> > > > rolled
> > > > > > and we will make it (hopefully) abundantly clear that connectors
> > need
> > > > to
> > > > > > account for missing original T/P/O getter methods if they expect
> to
> > > be
> > > > > > deployed on older Connect runtimes.
> > > > > >
> > > > > > > What is the expected behavior for Transformation
> > > > > > > implementations which do not use the newRecord
> > > > > > > methods and instead use public SinkRecord constructors?
> > > > > > > The KIP mentions this as a justification for the
> > > > > > > originalKafkaOffset method, but if existing implementations
> > > > > > > are using the existing constructors, those constructors won't
> > > > > > > forward the original T/P/O information to later transforms or
> > > > > > > the task.
> > > > > >
> > > > > > There shouldn't be any difference in behavior here - the
> framework
> > > will
> > > > > add
> > > > > > the original T/P/O metadata to the record after the entire
> > > > transformation
> > > > > > chain has been applied and just before sending the record to the
> > task
> > > > for
> > > > > > processing. The KIP doesn't propose that transformations
> themselves
> > > > > should
> > > > > > also be able to retrieve original T/P/O information for a sink
> > > record.
> > > > > >
> > > > > > > This reasoning and the KIP design seems to imply that the
> > > > > > > connector is better equipped to solve this problem than the
> > > > > > > framework, but the stated reasons are not convincing for me.
> > > > > >
> > > > > > This was added to the KIP by the original author, but I don't
> think
> > > the
> > > > > > intention was to imply that the connector is better equipped to
> > solve
> > > > > this
> > > > > > problem than the framework. The intention is to provide complete
> > > > > > information to the connector ("physical" and "virtual
> coordinates"
> > > > > instead
> > > > > > of the currently incomplete "virtual coordinates" as you've
> termed
> > > it)
> > > > so
> > > > > > that connectors can use the virtual coordinates for writing data
> to
> > > the
> > > > > > sink system and physical coordinates for offset reporting back to
> > the
> > > > > > framework. The rejected alternative basically says that we can't
> > do a
> > > > > > deterministic mapping from virtual coordinates to physical
> > > coordinates
> > > > > > without doing a lot of book-keeping.
> > > > > >
> > > > > > I agree with the rest of your analysis on the tradeoffs between
> the
> > > > > > proposed approach versus the seemingly more attractive approach
> of
> > > > > handling
> > > > > > everything purely in the framework and only exposing "virtual
> > > > > coordinates"
> > > > > > to the connectors. I think the biggest thorn here is maintaining
> > > > backward
> > > > > > compatibility with the considerable ecosystem of existing
> > connectors
> > > > > which
> > > > > > is something Connect has always been burdened by.
> > > > > >
> > > > > > Thanks,
> > > > > > Yash
> > > > > >
> > > > > > On Wed, Mar 8, 2023 at 6:54 AM Greg Harris
> > > > <greg.harris@aiven.io.invalid
> > > > > >
> > > > > > wrote:
> > > > > >
> > > > > > > Hi Yash,
> > > > > > >
> > > > > > > I always use this issue as an example of a bug being caused by
> > > design
> > > > > > > rather than by implementation error, and once it's fixed I'll
> > need
> > > to
> > > > > > find
> > > > > > > something else to talk about :)
> > > > > > > So glad to see this get fixed!
> > > > > > >
> > > > > > > I'll chime in to support some of the earlier discussions that
> > seem
> > > to
> > > > > > have
> > > > > > > been resolved:
> > > > > > >
> > > > > > > 1. With respect to SinkRecord methods vs an overloaded put(): I
> > > agree
> > > > > > with
> > > > > > > the current design but I justify it a little bit differently
> than
> > > has
> > > > > > > already been discussed.
> > > > > > > If we were designing this interface on day 1 without backwards
> > > > > > > compatibility in mind, which design would make more sense? Or
> > for a
> > > > > > > different framing: In the future when old runtimes and
> connectors
> > > are
> > > > > > > retired and the old interfaces are removed, which design is
> going
> > > to
> > > > > look
> > > > > > > more strange and unmotivated?
> > > > > > > Applied to this design decision, I would say that the original
> > > T/P/O
> > > > > are
> > > > > > > properties of a single SinkRecord and make sense as getters,
> and
> > it
> > > > > would
> > > > > > > be strange to store them in an auxiliary map.
> > > > > > >
> > > > > > > 2. Following up this change with a compatibility library to
> make
> > > the
> > > > > > > interface easier to use is the right choice to make here. This
> > > change
> > > > > > > should be focused on correctness in allowing developers to fix
> > the
> > > > > > > incompatibility and we can be concerned with coming up with a
> > more
> > > > > > > ergonomic solution in the compatibility library.
> > > > > > > The API should be focused on generality, correctness, and
> > > performance
> > > > > > > because those cannot be worked-around after the fact. Connector
> > > > > > > implementations and/or libraries can be concerned with trading
> > off
> > > > some
> > > > > > > generality and/or performance for ease-of-use.
> > > > > > >
> > > > > > > 3. I think that the difference in behavior of the new
> open/close
> > > > > methods
> > > > > > as
> > > > > > > compared to the old methods is significant, and requires good
> > > > > > documentation
> > > > > > > to help connector developers avoid lazy and incorrect
> > migrations. I
> > > > am
> > > > > > > happy to have that addressed in code review after the KIP is
> > > > approved.
> > > > > > >
> > > > > > > I had some questions:
> > > > > > >
> > > > > > > 4. What is the expected state/behavior for SinkRecords which do
> > not
> > > > > have
> > > > > > > original T/P/O information after the upgrade? Just browsing, it
> > > > appears
> > > > > > > that tests make extensive use of the existing public SinkRecord
> > > > > > > constructors for both Transformations and Connectors.
> > > > > > >
> > > > > > > 5. What is the expected behavior for Transformation
> > implementations
> > > > > which
> > > > > > > do not use the newRecord methods and instead use public
> > SinkRecord
> > > > > > > constructors? The KIP mentions this as a justification for the
> > > > > > > originalKafkaOffset method, but if existing implementations are
> > > using
> > > > > the
> > > > > > > existing constructors, those constructors won't forward the
> > > original
> > > > > > T/P/O
> > > > > > > information to later transforms or the task.
> > > > > > >
> > > > > > > For the last few points, I want to discuss this rejected
> > > alternative:
> > > > > > >
> > > > > > > > Address the offsets problem entirely within the framework,
> > doing
> > > > some
> > > > > > > kind of mapping from the transformed topic back to the original
> > > > topic.
> > > > > > > > * This would only work in the cases where there’s no overlap
> > > > between
> > > > > > the
> > > > > > > transformed topic names, but would break for the rest of the
> > > > > > > transformations (e.g. static transformation, topic = “a”).
> > > > > > > > * Even if we wanted to limit the support to those cases, it
> > would
> > > > > > require
> > > > > > > considerable bookkeeping to add a validation to verify that the
> > > > > > > transformation chain adheres to that expectation (and fail fast
> > if
> > > it
> > > > > > > doesn’t).
> > > > > > >
> > > > > > > 6. This reasoning and the KIP design seems to imply that the
> > > > connector
> > > > > is
> > > > > > > better equipped to solve this problem than the framework, but
> the
> > > > > stated
> > > > > > > reasons are not convincing for me.
> > > > > > > * A static transformation still causes an offset collision in
> the
> > > > > > connector
> > > > > > > * The connector is not permitted to see the transformation
> chain
> > to
> > > > do
> > > > > > any
> > > > > > > fail-fast assertions
> > > > > > >
> > > > > > > Suppose we were to think of the records at the end of the
> > > > > transformation
> > > > > > > chain as being in "virtual partitions" with "virtual offsets".
> > > > > > > For example, with identity-routing SMTs, the virtual
> coordinates
> > > are
> > > > > > > exactly the same as the underlying physical coordinates. For
> 1-1
> > > > > renames,
> > > > > > > each virtual topic would be the renamed topic corresponding to
> > the
> > > > > > > underlying topic. For fan-out from one topic to multiple
> virtual
> > > > > topics,
> > > > > > > virtual offsets would use the underlying kafka offsets with
> gaps
> > > for
> > > > > > > records going to other virtual partitions. Virtual topics with
> > > > dropped
> > > > > > > records have similar gaps in the offsets.
> > > > > > > Currently, these virtual coordinates are passed into the
> > connector
> > > > via
> > > > > > > SinkTask::put, but SinkTask::open/close/preCommit and
> > > > > > > SinkTaskContext::assignment/offsets/pause/resume all use
> physical
> > > > > > > coordinates.
> > > > > > > This proposal patches put,open, and close to have both physical
> > and
> > > > > > virtual
> > > > > > > coordinates, but leaves the other methods with physical
> > > coordinates.
> > > > > > After
> > > > > > > this proposal, connectors would be intentionally made aware of
> > the
> > > > > > > distinction between physical and virtual coordinates, and
> manage
> > > > their
> > > > > > own
> > > > > > > bookkeeping for the two systems.
> > > > > > >
> > > > > > > To avoid that connector logic, we could use virtual coordinates
> > in
> > > > all
> > > > > > > connector calls, never revealing that they are different from
> the
> > > > > > physical
> > > > > > > coordinates. There's a whole design shopping list that we'd
> need:
> > > > > > > * Renumbering mechanism for disambiguating and making virtual
> > > offsets
> > > > > > > monotonic in the case of topic/partition collisions
> > > > > > > * Data structure and strategy for translating virtual offsets
> > back
> > > to
> > > > > > > physical offsets
> > > > > > > * New limits on SinkTaskContext::offsets() calls to prevent
> > > rewinding
> > > > > > > before the latest commit
> > > > > > > * Backwards compatibility and upgrade design
> > > > > > >
> > > > > > > 7. This alternative was very appealing to me, because the
> > strength
> > > > of a
> > > > > > > plugin framework is the composability of different components.
> > > Among
> > > > a
> > > > > > > collection of N connectors and M transforms, it should ideally
> > only
> > > > > take
> > > > > > > N + M work to understand how the components combine to build
> the
> > > > whole.
> > > > > > > However, once you start adding special cases to some plugins to
> > > > support
> > > > > > > interactions with others, the whole system can take N * M work
> to
> > > > > > > understand. From a complexity standpoint, it would be very good
> > for
> > > > the
> > > > > > > framework to solve this in a way which was connector-agnostic.
> > > > > > > The current design compromises the logical isolation of the
> > plugins
> > > > > > > slightly, but they can collapse offsets very
> memory-efficiently,
> > > and
> > > > > > re-use
> > > > > > > the existing raw coordinate functions and keep everything else
> > > > > backwards
> > > > > > > compatible. After deriving all of the above, I think that's a
> > > > > reasonable
> > > > > > > tradeoff to make.
> > > > > > >
> > > > > > > Thanks,
> > > > > > > Greg
> > > > > > >
> > > > > > > On Tue, Feb 21, 2023 at 10:17 AM Chris Egerton
> > > > <chrise@aiven.io.invalid
> > > > > >
> > > > > > > wrote:
> > > > > > >
> > > > > > > > Hi Yash,
> > > > > > > >
> > > > > > > > We'll probably want to make a few tweaks to the Javadocs for
> > the
> > > > new
> > > > > > > > methods (I'm imagining that notes on compatibility with older
> > > > > versions
> > > > > > > will
> > > > > > > > be required), but I believe what's proposed in the KIP is
> good
> > > > enough
> > > > > > to
> > > > > > > > approve with the understanding that it may not exactly match
> > what
> > > > > gets
> > > > > > > > implemented/merged.
> > > > > > > >
> > > > > > > > LGTM, thanks again for the KIP!
> > > > > > > >
> > > > > > > > Cheers,
> > > > > > > >
> > > > > > > > Chris
> > > > > > > >
> > > > > > > > On Tue, Feb 21, 2023 at 12:18 PM Yash Mayya <
> > > yash.mayya@gmail.com>
> > > > > > > wrote:
> > > > > > > >
> > > > > > > > > Hi Chris,
> > > > > > > > >
> > > > > > > > > > we might try to introduce a framework-level configuration
> > > > > > > > > > property to dictate which of the pre-transform and
> > > > post-transform
> > > > > > > > > > topic partitions are used for the fallback call to the
> > > > single-arg
> > > > > > > > > > variant if a task class has not overridden the multi-arg
> > > > variant
> > > > > > > > >
> > > > > > > > > Thanks for the explanation and I agree that this will be a
> > tad
> > > > bit
> > > > > > too
> > > > > > > > > convoluted. :)
> > > > > > > > >
> > > > > > > > > Please do let me know if you'd like any further amendments
> to
> > > the
> > > > > > KIP!
> > > > > > > > >
> > > > > > > > > Thanks,
> > > > > > > > > Yash
> > > > > > > > >
> > > > > > > > > On Tue, Feb 21, 2023 at 8:42 PM Chris Egerton
> > > > > > <chrise@aiven.io.invalid
> > > > > > > >
> > > > > > > > > wrote:
> > > > > > > > >
> > > > > > > > > > Hi Yash,
> > > > > > > > > >
> > > > > > > > > > I think the use case for pre-transform TPO coordinates
> (and
> > > > topic
> > > > > > > > > partition
> > > > > > > > > > writers created/destroyed in close/open) tends to boil
> down
> > > to
> > > > > > > > > exactly-once
> > > > > > > > > > semantics, where it's desirable to preserve the
> guarantees
> > > that
> > > > > > Kafka
> > > > > > > > > > provides (every record has a unique TPO trio, and records
> > are
> > > > > > ordered
> > > > > > > > by
> > > > > > > > > > offset within a topic partition).
> > > > > > > > > >
> > > > > > > > > > It's my understanding that this approach is utilized in
> > > several
> > > > > > > > > connectors
> > > > > > > > > > out there today, and it might break these connectors to
> > start
> > > > > using
> > > > > > > the
> > > > > > > > > > post-transform topic partitions automatically in their
> > > > open/close
> > > > > > > > > methods.
> > > > > > > > > >
> > > > > > > > > > If we want to get really fancy with this and try to
> obviate
> > > or
> > > > at
> > > > > > > least
> > > > > > > > > > reduce the need for per-connector code changes, we might
> > try
> > > to
> > > > > > > > > introduce a
> > > > > > > > > > framework-level configuration property to dictate which
> of
> > > the
> > > > > > > > > > pre-transform and post-transform topic partitions are
> used
> > > for
> > > > > the
> > > > > > > > > fallback
> > > > > > > > > > call to the single-arg variant if a task class has not
> > > > overridden
> > > > > > the
> > > > > > > > > > multi-arg variant. But I think this is going a bit too
> far
> > > and
> > > > > > would
> > > > > > > > > prefer
> > > > > > > > > > to keep things simple(r) for now.
> > > > > > > > > >
> > > > > > > > > > Cheers,
> > > > > > > > > >
> > > > > > > > > > Chris
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > On Sun, Feb 19, 2023 at 2:34 AM Yash Mayya <
> > > > yash.mayya@gmail.com
> > > > > >
> > > > > > > > wrote:
> > > > > > > > > >
> > > > > > > > > > > Hi Chris,
> > > > > > > > > > >
> > > > > > > > > > > > I was actually envisioning something like `void
> > > > > > > > > > > > open(Collection<TopicPartition> originalPartitions,
> > > > > > > > > > > > Collection<TopicPartition> transformedPartitions)`
> > > > > > > > > > >
> > > > > > > > > > > Ah okay, this does make a lot more sense. Sorry, I
> think
> > I
> > > > > > > > > misunderstood
> > > > > > > > > > > you earlier. I do agree with you that this seems better
> > > than
> > > > > > > > splitting
> > > > > > > > > it
> > > > > > > > > > > off into two new sets of open / close methods from a
> > > > complexity
> > > > > > > > > > standpoint.
> > > > > > > > > > >
> > > > > > > > > > > > Plus, if a connector is intentionally designed to use
> > > > > > > > > > > > pre-transformation topic partitions in its open/close
> > > > > > > > > > > > methods, wouldn't we just be trading one form of the
> > > > > > > > > > > >  problem for another by making this switch?
> > > > > > > > > > >
> > > > > > > > > > > On thinking about this a bit more, I'm not so convinced
> > > that
> > > > we
> > > > > > > need
> > > > > > > > to
> > > > > > > > > > > expose the pre-transform / original topic partitions in
> > the
> > > > new
> > > > > > > open
> > > > > > > > /
> > > > > > > > > > > close methods. The purpose of the open / close methods
> is
> > > to
> > > > > > allow
> > > > > > > > sink
> > > > > > > > > > > tasks to allocate and deallocate resources for each
> topic
> > > > > > partition
> > > > > > > > > > > assigned to the task and the purpose of topic-mutating
> > SMTs
> > > > is
> > > > > to
> > > > > > > > > > > essentially modify the source topic name from the point
> > of
> > > > view
> > > > > > of
> > > > > > > > the
> > > > > > > > > > sink
> > > > > > > > > > > connector. Why would a sink connector ever need to or
> > want
> > > to
> > > > > > > > allocate
> > > > > > > > > > > resources for pre-transform topic partitions? Is the
> > > argument
> > > > > > here
> > > > > > > > that
> > > > > > > > > > > since we'll be exposing both the pre-transform and
> > > > > post-transform
> > > > > > > > topic
> > > > > > > > > > > partitions per record, we should also expose the same
> > info
> > > > via
> > > > > > > open /
> > > > > > > > > > close
> > > > > > > > > > > and allow sink connector implementations to disregard
> > > > > > > topic-mutating
> > > > > > > > > SMTs
> > > > > > > > > > > completely if they wanted to?
> > > > > > > > > > >
> > > > > > > > > > > Either way, I've gone ahead and updated the KIP to
> > reflect
> > > > all
> > > > > of
> > > > > > > > > > > our previous discussion here since it had become quite
> > > > > outdated.
> > > > > > > I've
> > > > > > > > > > also
> > > > > > > > > > > updated the KIP title from "Sink Connectors: Support
> > > > > > topic-mutating
> > > > > > > > > SMTs
> > > > > > > > > > > for async connectors (preCommit users)" to "Allow sink
> > > > > connectors
> > > > > > > to
> > > > > > > > be
> > > > > > > > > > > used with topic-mutating SMTs" since the improvements
> to
> > > the
> > > > > > open /
> > > > > > > > > close
> > > > > > > > > > > mechanism doesn't pertain only to asynchronous sink
> > > > connectors.
> > > > > > The
> > > > > > > > new
> > > > > > > > > > KIP
> > > > > > > > > > > URL is:
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-793%3A+Allow+sink+connectors+to+be+used+with+topic-mutating+SMTs
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > Thanks,
> > > > > > > > > > > Yash
> > > > > > > > > > >
> > > > > > > > > > > On Tue, Feb 14, 2023 at 11:39 PM Chris Egerton
> > > > > > > > <chrise@aiven.io.invalid
> > > > > > > > > >
> > > > > > > > > > > wrote:
> > > > > > > > > > >
> > > > > > > > > > > > Hi Yash,
> > > > > > > > > > > >
> > > > > > > > > > > > I was actually envisioning something like `void
> > > > > > > > > > > > open(Collection<TopicPartition>
> > > > > > > > > > > > originalPartitions, Collection<TopicPartition>
> > > > > > > > > transformedPartitions)`,
> > > > > > > > > > > > since we already convert and transform each batch of
> > > > records
> > > > > > that
> > > > > > > > we
> > > > > > > > > > poll
> > > > > > > > > > > > from the sink task's consumer en masse, meaning we
> > could
> > > > > > discover
> > > > > > > > > > several
> > > > > > > > > > > > new transformed partitions in between consecutive
> calls
> > > to
> > > > > > > > > > SinkTask::put.
> > > > > > > > > > > >
> > > > > > > > > > > > It's also worth noting that we'll probably want to
> > > > deprecate
> > > > > > the
> > > > > > > > > > existing
> > > > > > > > > > > > open/close methods, at which point keeping one
> > > > non-deprecated
> > > > > > > > variant
> > > > > > > > > > of
> > > > > > > > > > > > each seems more appealing and less complex than
> keeping
> > > > two.
> > > > > > > > > > > >
> > > > > > > > > > > > Honestly though, I think we're both on the same page
> > > enough
> > > > > > that
> > > > > > > I
> > > > > > > > > > > wouldn't
> > > > > > > > > > > > object to either approach. We've probably reached the
> > > > > > saturation
> > > > > > > > > point
> > > > > > > > > > > for
> > > > > > > > > > > > ROI here and as long as we provide developers a way
> to
> > > get
> > > > > the
> > > > > > > > > > > information
> > > > > > > > > > > > they need from the runtime and take care to add
> > Javadocs
> > > > and
> > > > > > > update
> > > > > > > > > our
> > > > > > > > > > > > docs page (possibly including the connector
> development
> > > > > > > > quickstart),
> > > > > > > > > it
> > > > > > > > > > > > should be fine.
> > > > > > > > > > > >
> > > > > > > > > > > > At this point, it might be worth updating the KIP
> based
> > > on
> > > > > > recent
> > > > > > > > > > > > discussion so that others can see the latest
> proposal,
> > > and
> > > > we
> > > > > > can
> > > > > > > > > both
> > > > > > > > > > > take
> > > > > > > > > > > > a look and make sure everything looks good enough
> > before
> > > > > > opening
> > > > > > > a
> > > > > > > > > vote
> > > > > > > > > > > > thread.
> > > > > > > > > > > >
> > > > > > > > > > > > Finally, I think you make a convincing case for a
> > > > time-based
> > > > > > > > eviction
> > > > > > > > > > > > policy. I wasn't thinking about the fairly common SMT
> > > > pattern
> > > > > > of
> > > > > > > > > > > deriving a
> > > > > > > > > > > > topic name from, e.g., a record field or header.
> > > > > > > > > > > >
> > > > > > > > > > > > Cheers,
> > > > > > > > > > > >
> > > > > > > > > > > > Chris
> > > > > > > > > > > >
> > > > > > > > > > > > On Tue, Feb 14, 2023 at 11:42 AM Yash Mayya <
> > > > > > > yash.mayya@gmail.com>
> > > > > > > > > > > wrote:
> > > > > > > > > > > >
> > > > > > > > > > > > > Hi Chris,
> > > > > > > > > > > > >
> > > > > > > > > > > > > > Plus, if a connector is intentionally designed to
> > > > > > > > > > > > > > use pre-transformation topic partitions in its
> > > > > > > > > > > > > > open/close methods, wouldn't we just be trading
> > > > > > > > > > > > > > one form of the problem for another by making
> this
> > > > > > > > > > > > > > switch?
> > > > > > > > > > > > >
> > > > > > > > > > > > > Thanks, this makes sense, and given that the KIP
> > > already
> > > > > > > > proposes a
> > > > > > > > > > way
> > > > > > > > > > > > for
> > > > > > > > > > > > > sink connector implementations to distinguish
> between
> > > > > > > > pre-transform
> > > > > > > > > > and
> > > > > > > > > > > > > post-transform topics per record, I think I'm
> > convinced
> > > > > that
> > > > > > > > going
> > > > > > > > > > with
> > > > > > > > > > > > new
> > > > > > > > > > > > > `open()` / `close()` methods is the right approach.
> > > > > However,
> > > > > > I
> > > > > > > > > still
> > > > > > > > > > > feel
> > > > > > > > > > > > > like having overloaded methods will make it a lot
> > less
> > > > > > > > unintuitive
> > > > > > > > > > > given
> > > > > > > > > > > > > that the two sets of methods would be different in
> > > terms
> > > > of
> > > > > > > when
> > > > > > > > > > > they're
> > > > > > > > > > > > > called and what arguments they are passed (also I'm
> > > > > presuming
> > > > > > > > that
> > > > > > > > > > the
> > > > > > > > > > > > > overloaded methods you're prescribing will only
> have
> > a
> > > > > single
> > > > > > > > > > > > > `TopicPartition` rather than a
> > > > `Collection<TopicPartition>`
> > > > > > as
> > > > > > > > > their
> > > > > > > > > > > > > parameters). I guess my concern is largely around
> the
> > > > fact
> > > > > > that
> > > > > > > > it
> > > > > > > > > > > won't
> > > > > > > > > > > > be
> > > > > > > > > > > > > possible to distinguish between the overloaded
> > methods'
> > > > use
> > > > > > > cases
> > > > > > > > > > just
> > > > > > > > > > > > from
> > > > > > > > > > > > > the method signatures. I agree that naming is going
> > to
> > > be
> > > > > > > > difficult
> > > > > > > > > > > here,
> > > > > > > > > > > > > but I think that having two sets of
> > > `SinkTask::openXyz` /
> > > > > > > > > > > > > `SinkTask::closeXyz` methods will be less
> complicated
> > > to
> > > > > > > > understand
> > > > > > > > > > > from
> > > > > > > > > > > > a
> > > > > > > > > > > > > connector developer perspective (as compared to
> > > > overloaded
> > > > > > > > methods
> > > > > > > > > > with
> > > > > > > > > > > > > only differing documentation). Of your suggested
> > > > options, I
> > > > > > > think
> > > > > > > > > > > > > `openPreTransform` / `openPostTransform` are the
> most
> > > > > > > > > comprehensible
> > > > > > > > > > > > ones.
> > > > > > > > > > > > >
> > > > > > > > > > > > > > BTW, I wouldn't say that we can't make
> assumptions
> > > > > > > > > > > > > > about the relationships between pre- and
> > > > > > post-transformation
> > > > > > > > > > > > > >  topic partitions.
> > > > > > > > > > > > >
> > > > > > > > > > > > > I meant that the framework wouldn't be able to
> > > > > > > deterministically
> > > > > > > > > know
> > > > > > > > > > > > when
> > > > > > > > > > > > > to close a post-transform topic partition given
> that
> > > SMTs
> > > > > > could
> > > > > > > > use
> > > > > > > > > > > > > per-record data / metadata to manipulate the topic
> > > names
> > > > as
> > > > > > and
> > > > > > > > how
> > > > > > > > > > > > > required (which supports the suggestion to use an
> > > > eviction
> > > > > > > policy
> > > > > > > > > > based
> > > > > > > > > > > > > mechanism to call SinkTask::close for
> post-transform
> > > > topic
> > > > > > > > > > partitions).
> > > > > > > > > > > > >
> > > > > > > > > > > > > > We might utilize a policy that assumes a
> > > deterministic
> > > > > > > > > > > > > > mapping from the former to the latter, for
> example.
> > > > > > > > > > > > >
> > > > > > > > > > > > > Wouldn't this be making the assumption that SMTs
> only
> > > use
> > > > > the
> > > > > > > > topic
> > > > > > > > > > > name
> > > > > > > > > > > > > itself and no other data / metadata while computing
> > the
> > > > new
> > > > > > > topic
> > > > > > > > > > name?
> > > > > > > > > > > > Are
> > > > > > > > > > > > > you suggesting that since this assumption could
> work
> > > for
> > > > a
> > > > > > > > majority
> > > > > > > > > > of
> > > > > > > > > > > > > SMTs, it might be more efficient overall in terms
> of
> > > > > reducing
> > > > > > > the
> > > > > > > > > > > number
> > > > > > > > > > > > of
> > > > > > > > > > > > > "false-positive" calls to
> > > `SinkTask::closePostTransform`
> > > > > (and
> > > > > > > > we'll
> > > > > > > > > > > also
> > > > > > > > > > > > be
> > > > > > > > > > > > > able to call `SinkTask::closePostTransform`
> > immediately
> > > > > after
> > > > > > > > topic
> > > > > > > > > > > > > partitions are revoked from the consumer)? I was
> > > thinking
> > > > > > > > something
> > > > > > > > > > > more
> > > > > > > > > > > > > generic along the lines of a simple time based
> > eviction
> > > > > > policy
> > > > > > > > that
> > > > > > > > > > > > > wouldn't be making any assumptions regarding the
> SMT
> > > > > > > > > implementations.
> > > > > > > > > > > > > Either way, I do like your earlier suggestion of
> > > keeping
> > > > > this
> > > > > > > > logic
> > > > > > > > > > > > > internal and not painting ourselves into a corner
> by
> > > > > > promising
> > > > > > > > any
> > > > > > > > > > > > > particular behavior in the KIP.
> > > > > > > > > > > > >
> > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > Yash
> > > > > > > > > > > > >
> > > > > > > > > > > > > On Tue, Feb 14, 2023 at 1:08 AM Chris Egerton
> > > > > > > > > > <chrise@aiven.io.invalid
> > > > > > > > > > > >
> > > > > > > > > > > > > wrote:
> > > > > > > > > > > > >
> > > > > > > > > > > > > > Hi Yash,
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > I think the key difference between adding
> > > > > methods/overloads
> > > > > > > > > related
> > > > > > > > > > > to
> > > > > > > > > > > > > > SinkTask::open/SinkTask::close and SinkTask::put
> is
> > > > that
> > > > > > this
> > > > > > > > > isn't
> > > > > > > > > > > > > > auxiliary information that may or may not be
> useful
> > > to
> > > > > > > > connector
> > > > > > > > > > > > > > developers. It's actually critical for them to
> > > > understand
> > > > > > the
> > > > > > > > > > > > difference
> > > > > > > > > > > > > > between the two concepts here, even if they look
> > very
> > > > > > > similar.
> > > > > > > > > And
> > > > > > > > > > > > yes, I
> > > > > > > > > > > > > > do believe that switching from pre-transform to
> > > > > > > post-transform
> > > > > > > > > > topic
> > > > > > > > > > > > > > partitions is too big a change in behavior here.
> > > Plus,
> > > > > if a
> > > > > > > > > > connector
> > > > > > > > > > > > is
> > > > > > > > > > > > > > intentionally designed to use pre-transformation
> > > topic
> > > > > > > > partitions
> > > > > > > > > > in
> > > > > > > > > > > > its
> > > > > > > > > > > > > > open/close methods, wouldn't we just be trading
> one
> > > > form
> > > > > of
> > > > > > > the
> > > > > > > > > > > problem
> > > > > > > > > > > > > for
> > > > > > > > > > > > > > another by making this switch?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > One possible alternative to overloading the
> > existing
> > > > > > methods
> > > > > > > is
> > > > > > > > > to
> > > > > > > > > > > > split
> > > > > > > > > > > > > > SinkTask::open into openOriginal (or possibly
> > > > > openPhysical
> > > > > > or
> > > > > > > > > > > > > > openPreTransform) and openTransformed (or
> > openLogical
> > > > or
> > > > > > > > > > > > > > openPostTransform), with a similar change for
> > > > > > > SinkTask::close.
> > > > > > > > > The
> > > > > > > > > > > > > default
> > > > > > > > > > > > > > implementation for SinkTask::openOriginal can be
> to
> > > > call
> > > > > > > > > > > > SinkTask::open,
> > > > > > > > > > > > > > and the same can go for SinkTask::close.
> However, I
> > > > > prefer
> > > > > > > > > > > overloading
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > existing methods since this alternative increases
> > > > > > complexity
> > > > > > > > and
> > > > > > > > > > none
> > > > > > > > > > > > of
> > > > > > > > > > > > > > the names are very informative.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > BTW, I wouldn't say that we can't make
> assumptions
> > > > about
> > > > > > the
> > > > > > > > > > > > > relationships
> > > > > > > > > > > > > > between pre- and post-transformation topic
> > > partitions.
> > > > We
> > > > > > > might
> > > > > > > > > > > > utilize a
> > > > > > > > > > > > > > policy that assumes a deterministic mapping from
> > the
> > > > > former
> > > > > > > to
> > > > > > > > > the
> > > > > > > > > > > > > latter,
> > > > > > > > > > > > > > for example. The distinction I'd draw is that the
> > > > > > assumptions
> > > > > > > > we
> > > > > > > > > > make
> > > > > > > > > > > > can
> > > > > > > > > > > > > > and probably should favor some cases in terms of
> > > > > > performance
> > > > > > > > > (i.e.,
> > > > > > > > > > > > > > reducing the number of unnecessary calls to
> > > close/open
> > > > > > over a
> > > > > > > > > given
> > > > > > > > > > > > sink
> > > > > > > > > > > > > > task's lifetime), but should not lead to
> guaranteed
> > > > > > resource
> > > > > > > > > leaks
> > > > > > > > > > or
> > > > > > > > > > > > > > failure to obey API contract in any cases.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Cheers,
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Chris
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > On Mon, Feb 13, 2023 at 10:54 AM Yash Mayya <
> > > > > > > > > yash.mayya@gmail.com>
> > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Hi Chris,
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > especially if connectors are intentionally
> > > designed
> > > > > > > around
> > > > > > > > > > > > > > > > original topic partitions instead of
> > transformed
> > > > > ones.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Ha, that's a good point and reminds me of
> Hyrum's
> > > Law
> > > > > [1]
> > > > > > > :)
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > I think we have to provide connector
> developers
> > > > with
> > > > > > some
> > > > > > > > > > > > > > > > way to differentiate between the two, but
> maybe
> > > > > > there's a
> > > > > > > > way
> > > > > > > > > > > > > > > >  to do this that I haven't thought of yet
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > I can't think of a better way to do this
> either;
> > > > would
> > > > > > > > invoking
> > > > > > > > > > the
> > > > > > > > > > > > > > > existing `SinkTask::open` and `SinkTask::close`
> > > > methods
> > > > > > > with
> > > > > > > > > > > > > > post-transform
> > > > > > > > > > > > > > > topic partitions instead of pre-transform topic
> > > > > > partitions
> > > > > > > > not
> > > > > > > > > be
> > > > > > > > > > > > > > > acceptable even in a minor / major AK release?
> I
> > > feel
> > > > > > like
> > > > > > > > the
> > > > > > > > > > > > proposed
> > > > > > > > > > > > > > > approach of adding overloaded `SinkTask::open`
> /
> > > > > > > > > > `SinkTask::close`
> > > > > > > > > > > > > > methods
> > > > > > > > > > > > > > > to differentiate between pre-transform and
> > > > > post-transform
> > > > > > > > topic
> > > > > > > > > > > > > > partitions
> > > > > > > > > > > > > > > has similar pitfalls to the idea of the
> > overloaded
> > > > > > > > > > `SinkTask::put`
> > > > > > > > > > > > > method
> > > > > > > > > > > > > > > we discarded earlier.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Either way, I'm glad that the general idea
> of a
> > > > cache
> > > > > > and
> > > > > > > > > > > > > > > > eviction policy for SinkTask::close seem
> > > > reasonable;
> > > > > if
> > > > > > > > > > > > > > > > we decide to go this route, it might make
> sense
> > > for
> > > > > the
> > > > > > > KIP
> > > > > > > > > > > > > > > > to include an outline of one or more
> high-level
> > > > > > > strategies
> > > > > > > > > > > > > > > > we might take, but without promising any
> > > particular
> > > > > > > > behavior
> > > > > > > > > > > > > > > > beyond occasionally calling SinkTask::close
> for
> > > > > > > > > post-transform
> > > > > > > > > > > > > > > > topic partitions. I'm hoping that this logic
> > can
> > > > stay
> > > > > > > > > internal,
> > > > > > > > > > > > > > > > and by notpainting ourselves into a corner
> with
> > > the
> > > > > > KIP,
> > > > > > > we
> > > > > > > > > > > > > > > > give ourselves leeway to tweak it in the
> future
> > > if
> > > > > > > > necessary
> > > > > > > > > > > > > > > > without filing another KIP or introducing a
> > > > pluggable
> > > > > > > > > > interface.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Thanks, that's a good idea. Given the
> flexibility
> > > of
> > > > > > SMTs,
> > > > > > > > the
> > > > > > > > > > > > > framework
> > > > > > > > > > > > > > > can't really make any assumptions around topic
> > > > > partitions
> > > > > > > > post
> > > > > > > > > > > > > > > transformation nor does it have any way to
> > > > definitively
> > > > > > get
> > > > > > > > any
> > > > > > > > > > > such
> > > > > > > > > > > > > > > information from transformations which is why
> the
> > > > idea
> > > > > > of a
> > > > > > > > > cache
> > > > > > > > > > > > with
> > > > > > > > > > > > > an
> > > > > > > > > > > > > > > eviction policy makes perfect sense!
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > [1] - https://www.hyrumslaw.com/
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > Yash
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > On Thu, Feb 9, 2023 at 9:38 PM Chris Egerton
> > > > > > > > > > > <chrise@aiven.io.invalid
> > > > > > > > > > > > >
> > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Hi Yash,
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > So it looks like with the current state of
> > > > affairs,
> > > > > > > sink
> > > > > > > > > > tasks
> > > > > > > > > > > > that
> > > > > > > > > > > > > > > only
> > > > > > > > > > > > > > > > instantiate writers in the SinkTask::open
> > method
> > > > (and
> > > > > > > don't
> > > > > > > > > do
> > > > > > > > > > > the
> > > > > > > > > > > > > lazy
> > > > > > > > > > > > > > > > instantiation in SinkTask::put that you
> > > mentioned)
> > > > > > might
> > > > > > > > fail
> > > > > > > > > > > when
> > > > > > > > > > > > > used
> > > > > > > > > > > > > > > > with topic/partition mutating SMTs even if
> they
> > > > don't
> > > > > > do
> > > > > > > > any
> > > > > > > > > > > > > > asynchronous
> > > > > > > > > > > > > > > > processing?
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Yep, exactly 👍
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > What do you think about retaining just the
> > > > existing
> > > > > > > > methods
> > > > > > > > > > > > > > > > but changing when they're called in the
> Connect
> > > > > > runtime?
> > > > > > > > For
> > > > > > > > > > > > > instance,
> > > > > > > > > > > > > > > > instead of calling SinkTask::open after
> > partition
> > > > > > > > assignment
> > > > > > > > > > > post a
> > > > > > > > > > > > > > > > consumer group rebalance, we could cache the
> > > > > currently
> > > > > > > > "seen"
> > > > > > > > > > > topic
> > > > > > > > > > > > > > > > partitions (post transformation) and before
> > each
> > > > call
> > > > > > to
> > > > > > > > > > > > > SinkTask::put
> > > > > > > > > > > > > > > > check whether there's any new "unseen" topic
> > > > > > partitions,
> > > > > > > > and
> > > > > > > > > if
> > > > > > > > > > > so
> > > > > > > > > > > > > call
> > > > > > > > > > > > > > > > SinkTask::open (and also update the cache of
> > > > course).
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > IMO the issue here is that it's a drastic
> > change
> > > in
> > > > > > > > behavior
> > > > > > > > > to
> > > > > > > > > > > > start
> > > > > > > > > > > > > > > > invoking SinkTask::open and SinkTask::close
> > with
> > > > > > > > > post-transform
> > > > > > > > > > > > topic
> > > > > > > > > > > > > > > > partitions instead of pre-transform,
> especially
> > > if
> > > > > > > > connectors
> > > > > > > > > > are
> > > > > > > > > > > > > > > > intentionally designed around original topic
> > > > > partitions
> > > > > > > > > instead
> > > > > > > > > > > of
> > > > > > > > > > > > > > > > transformed ones. I think we have to provide
> > > > > connector
> > > > > > > > > > developers
> > > > > > > > > > > > > with
> > > > > > > > > > > > > > > some
> > > > > > > > > > > > > > > > way to differentiate between the two, but
> maybe
> > > > > > there's a
> > > > > > > > way
> > > > > > > > > > to
> > > > > > > > > > > do
> > > > > > > > > > > > > > this
> > > > > > > > > > > > > > > > that I haven't thought of yet. Interested to
> > hear
> > > > > your
> > > > > > > > > > thoughts.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Either way, I'm glad that the general idea
> of a
> > > > cache
> > > > > > and
> > > > > > > > > > > eviction
> > > > > > > > > > > > > > policy
> > > > > > > > > > > > > > > > for SinkTask::close seem reasonable; if we
> > decide
> > > > to
> > > > > go
> > > > > > > > this
> > > > > > > > > > > route,
> > > > > > > > > > > > > it
> > > > > > > > > > > > > > > > might make sense for the KIP to include an
> > > outline
> > > > of
> > > > > > one
> > > > > > > > or
> > > > > > > > > > more
> > > > > > > > > > > > > > > > high-level strategies we might take, but
> > without
> > > > > > > promising
> > > > > > > > > any
> > > > > > > > > > > > > > particular
> > > > > > > > > > > > > > > > behavior beyond occasionally calling
> > > > SinkTask::close
> > > > > > for
> > > > > > > > > > > > > post-transform
> > > > > > > > > > > > > > > > topic partitions. I'm hoping that this logic
> > can
> > > > stay
> > > > > > > > > internal,
> > > > > > > > > > > and
> > > > > > > > > > > > > by
> > > > > > > > > > > > > > > not
> > > > > > > > > > > > > > > > painting ourselves into a corner with the
> KIP,
> > we
> > > > > give
> > > > > > > > > > ourselves
> > > > > > > > > > > > > leeway
> > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > tweak it in the future if necessary without
> > > filing
> > > > > > > another
> > > > > > > > > KIP
> > > > > > > > > > or
> > > > > > > > > > > > > > > > introducing a pluggable interface.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Cheers,
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Chris
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > On Thu, Feb 9, 2023 at 7:39 AM Yash Mayya <
> > > > > > > > > > yash.mayya@gmail.com>
> > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Hi Chris,
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Thanks for the feedback.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 1) That's a fair point; while I did scan
> > > > everything
> > > > > > > > > publicly
> > > > > > > > > > > > > > available
> > > > > > > > > > > > > > > on
> > > > > > > > > > > > > > > > > GitHub, you're right in that it won't cover
> > all
> > > > > > > possible
> > > > > > > > > SMTs
> > > > > > > > > > > > that
> > > > > > > > > > > > > > are
> > > > > > > > > > > > > > > > out
> > > > > > > > > > > > > > > > > there. Thanks for the example use-case as
> > well,
> > > > > I've
> > > > > > > > > updated
> > > > > > > > > > > the
> > > > > > > > > > > > > KIP
> > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > add
> > > > > > > > > > > > > > > > > the two new proposed methods.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 2) So it looks like with the current state
> of
> > > > > > affairs,
> > > > > > > > sink
> > > > > > > > > > > tasks
> > > > > > > > > > > > > > that
> > > > > > > > > > > > > > > > only
> > > > > > > > > > > > > > > > > instantiate writers in the SinkTask::open
> > > method
> > > > > (and
> > > > > > > > don't
> > > > > > > > > > do
> > > > > > > > > > > > the
> > > > > > > > > > > > > > lazy
> > > > > > > > > > > > > > > > > instantiation in SinkTask::put that you
> > > > mentioned)
> > > > > > > might
> > > > > > > > > fail
> > > > > > > > > > > > when
> > > > > > > > > > > > > > used
> > > > > > > > > > > > > > > > > with topic/partition mutating SMTs even if
> > they
> > > > > don't
> > > > > > > do
> > > > > > > > > any
> > > > > > > > > > > > > > > asynchronous
> > > > > > > > > > > > > > > > > processing? Since they could encounter
> > records
> > > in
> > > > > > > > > > SinkTask::put
> > > > > > > > > > > > > with
> > > > > > > > > > > > > > > > > topics/partitions that they might not have
> > > > created
> > > > > > > > writers
> > > > > > > > > > for.
> > > > > > > > > > > > > > Thanks
> > > > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > > pointing this out, it's definitely another
> > > > > > > > incompatibility
> > > > > > > > > > that
> > > > > > > > > > > > > needs
> > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > be
> > > > > > > > > > > > > > > > > called out and fixed. The overloaded method
> > > > > approach
> > > > > > is
> > > > > > > > > > > > > interesting,
> > > > > > > > > > > > > > > but
> > > > > > > > > > > > > > > > > comes with the caveat of yet more new
> methods
> > > > that
> > > > > > will
> > > > > > > > > need
> > > > > > > > > > to
> > > > > > > > > > > > be
> > > > > > > > > > > > > > > > > implemented by existing connectors if they
> > want
> > > > to
> > > > > > make
> > > > > > > > use
> > > > > > > > > > of
> > > > > > > > > > > > this
> > > > > > > > > > > > > > new
> > > > > > > > > > > > > > > > > functionality. What do you think about
> > > retaining
> > > > > just
> > > > > > > the
> > > > > > > > > > > > existing
> > > > > > > > > > > > > > > > methods
> > > > > > > > > > > > > > > > > but changing when they're called in the
> > Connect
> > > > > > > runtime?
> > > > > > > > > For
> > > > > > > > > > > > > > instance,
> > > > > > > > > > > > > > > > > instead of calling SinkTask::open after
> > > partition
> > > > > > > > > assignment
> > > > > > > > > > > > post a
> > > > > > > > > > > > > > > > > consumer group rebalance, we could cache
> the
> > > > > > currently
> > > > > > > > > "seen"
> > > > > > > > > > > > topic
> > > > > > > > > > > > > > > > > partitions (post transformation) and before
> > > each
> > > > > call
> > > > > > > to
> > > > > > > > > > > > > > SinkTask::put
> > > > > > > > > > > > > > > > > check whether there's any new "unseen"
> topic
> > > > > > > partitions,
> > > > > > > > > and
> > > > > > > > > > if
> > > > > > > > > > > > so
> > > > > > > > > > > > > > call
> > > > > > > > > > > > > > > > > SinkTask::open (and also update the cache
> of
> > > > > > course). I
> > > > > > > > > don't
> > > > > > > > > > > > think
> > > > > > > > > > > > > > > this
> > > > > > > > > > > > > > > > > would break the existing contract with sink
> > > tasks
> > > > > > where
> > > > > > > > > > > > > > SinkTask::open
> > > > > > > > > > > > > > > is
> > > > > > > > > > > > > > > > > expected to be called for a topic partition
> > > > before
> > > > > > any
> > > > > > > > > > records
> > > > > > > > > > > > from
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > topic partition are sent via SinkTask::put?
> > The
> > > > > > > > > > SinkTask::close
> > > > > > > > > > > > > case
> > > > > > > > > > > > > > > is a
> > > > > > > > > > > > > > > > > lot trickier however, and would require
> some
> > > sort
> > > > > of
> > > > > > > > cache
> > > > > > > > > > > > eviction
> > > > > > > > > > > > > > > > policy
> > > > > > > > > > > > > > > > > that would be deemed appropriate as you
> > pointed
> > > > out
> > > > > > > too.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > > Yash
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > On Mon, Feb 6, 2023 at 11:27 PM Chris
> Egerton
> > > > > > > > > > > > > > <chrise@aiven.io.invalid
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > Hi Yash,
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > I've had some time to think on this KIP
> > and I
> > > > > think
> > > > > > > I'm
> > > > > > > > > in
> > > > > > > > > > > > > > agreement
> > > > > > > > > > > > > > > > > about
> > > > > > > > > > > > > > > > > > not blocking it on an official
> > compatibility
> > > > > > library
> > > > > > > or
> > > > > > > > > > > adding
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > "ack"
> > > > > > > > > > > > > > > > > > API for sink records.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > I only have two more thoughts:
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > 1. Because it is possible to manipulate
> > sink
> > > > > record
> > > > > > > > > > > partitions
> > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > offsets
> > > > > > > > > > > > > > > > > > with the current API we provide for
> > > > > > transformations,
> > > > > > > I
> > > > > > > > > > still
> > > > > > > > > > > > > > believe
> > > > > > > > > > > > > > > > > > methods should be added to the SinkRecord
> > > class
> > > > > to
> > > > > > > > expose
> > > > > > > > > > the
> > > > > > > > > > > > > > > original
> > > > > > > > > > > > > > > > > > partition and offset, not just the
> original
> > > > > topic.
> > > > > > > The
> > > > > > > > > > > > additional
> > > > > > > > > > > > > > > > > cognitive
> > > > > > > > > > > > > > > > > > burden from these two methods is going to
> > be
> > > > > > minimal
> > > > > > > > > > anyways;
> > > > > > > > > > > > > once
> > > > > > > > > > > > > > > > users
> > > > > > > > > > > > > > > > > > understand the difference between the
> > > > transformed
> > > > > > > topic
> > > > > > > > > > name
> > > > > > > > > > > > and
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > original one, it's going to be trivial
> for
> > > them
> > > > > to
> > > > > > > > > > understand
> > > > > > > > > > > > how
> > > > > > > > > > > > > > > that
> > > > > > > > > > > > > > > > > same
> > > > > > > > > > > > > > > > > > difference applies for partitions and
> > > offsets.
> > > > > It's
> > > > > > > not
> > > > > > > > > > > enough
> > > > > > > > > > > > to
> > > > > > > > > > > > > > > scan
> > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > set of SMTs provided out of the box with
> > > > Connect,
> > > > > > > ones
> > > > > > > > > > > > developed
> > > > > > > > > > > > > by
> > > > > > > > > > > > > > > > > > Confluent, or even everything available
> on
> > > > > GitHub,
> > > > > > > > since
> > > > > > > > > > > there
> > > > > > > > > > > > > may
> > > > > > > > > > > > > > be
> > > > > > > > > > > > > > > > > > closed-source projects out there that
> rely
> > on
> > > > > this
> > > > > > > > > ability.
> > > > > > > > > > > One
> > > > > > > > > > > > > > > > potential
> > > > > > > > > > > > > > > > > > use case could be re-routing partitions
> > > between
> > > > > > Kafka
> > > > > > > > and
> > > > > > > > > > > some
> > > > > > > > > > > > > > other
> > > > > > > > > > > > > > > > > > sharded system.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > 2. We still have to address the
> > > SinkTask::open
> > > > > [1]
> > > > > > > and
> > > > > > > > > > > > > > > SinkTask::close
> > > > > > > > > > > > > > > > > [2]
> > > > > > > > > > > > > > > > > > methods. If a connector writes to the
> > > external
> > > > > > system
> > > > > > > > > using
> > > > > > > > > > > the
> > > > > > > > > > > > > > > > > transformed
> > > > > > > > > > > > > > > > > > topic partitions it reads from Kafka,
> then
> > > it's
> > > > > > > > possible
> > > > > > > > > > for
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > connector
> > > > > > > > > > > > > > > > > > to lazily instantiate writers for topic
> > > > > partitions
> > > > > > as
> > > > > > > > it
> > > > > > > > > > > > > encounters
> > > > > > > > > > > > > > > > them
> > > > > > > > > > > > > > > > > > from records provided in SinkTask::put.
> > > > However,
> > > > > > > > > connectors
> > > > > > > > > > > > also
> > > > > > > > > > > > > > > need a
> > > > > > > > > > > > > > > > > way
> > > > > > > > > > > > > > > > > > to de-allocate those writers (and the
> > > resources
> > > > > > used
> > > > > > > by
> > > > > > > > > > them)
> > > > > > > > > > > > > over
> > > > > > > > > > > > > > > > time,
> > > > > > > > > > > > > > > > > > which they can't do as easily. One
> possible
> > > > > > approach
> > > > > > > > here
> > > > > > > > > > is
> > > > > > > > > > > to
> > > > > > > > > > > > > > > > overload
> > > > > > > > > > > > > > > > > > SinkTask::open and SinkTask::close with
> > > > variants
> > > > > > that
> > > > > > > > > > > > distinguish
> > > > > > > > > > > > > > > > between
> > > > > > > > > > > > > > > > > > transformed and original topic
> partitions,
> > > and
> > > > > > > default
> > > > > > > > to
> > > > > > > > > > > > > invoking
> > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > existing methods with just the original
> > topic
> > > > > > > > partitions.
> > > > > > > > > > We
> > > > > > > > > > > > > would
> > > > > > > > > > > > > > > then
> > > > > > > > > > > > > > > > > > have several options for how the Connect
> > > > runtime
> > > > > > can
> > > > > > > > > invoke
> > > > > > > > > > > > these
> > > > > > > > > > > > > > > > > methods,
> > > > > > > > > > > > > > > > > > but in general, an approach that
> guarantees
> > > > that
> > > > > > > tasks
> > > > > > > > > are
> > > > > > > > > > > > > notified
> > > > > > > > > > > > > > > of
> > > > > > > > > > > > > > > > > > transformed topic partitions in
> > > SinkTask::open
> > > > > > before
> > > > > > > > any
> > > > > > > > > > > > records
> > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > > that
> > > > > > > > > > > > > > > > > > partition are given to it in
> SinkTask::put,
> > > and
> > > > > > > makes a
> > > > > > > > > > > > > best-effort
> > > > > > > > > > > > > > > > > attempt
> > > > > > > > > > > > > > > > > > to close transformed topic partitions
> that
> > > > appear
> > > > > > to
> > > > > > > no
> > > > > > > > > > > longer
> > > > > > > > > > > > be
> > > > > > > > > > > > > > in
> > > > > > > > > > > > > > > > use
> > > > > > > > > > > > > > > > > > based on some eviction policy, would
> > probably
> > > > be
> > > > > > > > > > sufficient.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > [1] -
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://kafka.apache.org/33/javadoc/org/apache/kafka/connect/sink/SinkTask.html#open(java.util.Collection)
> > > > > > > > > > > > > > > > > > [2] -
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://kafka.apache.org/33/javadoc/org/apache/kafka/connect/sink/SinkTask.html#close(java.util.Collection)
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > Cheers,
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > Chris
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > On Sat, Nov 5, 2022 at 5:46 AM Yash
> Mayya <
> > > > > > > > > > > > yash.mayya@gmail.com>
> > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Hi Chris,
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Thanks a lot for your inputs!
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > would provide a simple, clean
> interface
> > > for
> > > > > > > > > developers
> > > > > > > > > > to
> > > > > > > > > > > > > > > determine
> > > > > > > > > > > > > > > > > > > > which features are supported by the
> > > version
> > > > > of
> > > > > > > the
> > > > > > > > > > > Connect
> > > > > > > > > > > > > > > runtime
> > > > > > > > > > > > > > > > > > > > that their plugin has been deployed
> > onto
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > I do like the idea of having such a
> > public
> > > > > > > > > compatibility
> > > > > > > > > > > > > library
> > > > > > > > > > > > > > -
> > > > > > > > > > > > > > > I
> > > > > > > > > > > > > > > > > > think
> > > > > > > > > > > > > > > > > > > it would remove a lot of restrictions
> > from
> > > > > > > framework
> > > > > > > > > > > > > development
> > > > > > > > > > > > > > if
> > > > > > > > > > > > > > > > it
> > > > > > > > > > > > > > > > > > were
> > > > > > > > > > > > > > > > > > > to be widely adopted.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > we might consider adding an API to
> > "ack"
> > > > sink
> > > > > > > > records
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > I agree that this does seem like a more
> > > > > intuitive
> > > > > > > and
> > > > > > > > > > clean
> > > > > > > > > > > > > API,
> > > > > > > > > > > > > > > but
> > > > > > > > > > > > > > > > > I'm
> > > > > > > > > > > > > > > > > > > concerned about the backward
> > compatibility
> > > > > > headache
> > > > > > > > > we'd
> > > > > > > > > > be
> > > > > > > > > > > > > > > imposing
> > > > > > > > > > > > > > > > on
> > > > > > > > > > > > > > > > > > all
> > > > > > > > > > > > > > > > > > > existing sink connectors. Connector
> > > > developers
> > > > > > will
> > > > > > > > > have
> > > > > > > > > > to
> > > > > > > > > > > > > > > maintain
> > > > > > > > > > > > > > > > > two
> > > > > > > > > > > > > > > > > > > separate ways of doing offset
> management
> > if
> > > > > they
> > > > > > > want
> > > > > > > > > to
> > > > > > > > > > > use
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > new
> > > > > > > > > > > > > > > > > API
> > > > > > > > > > > > > > > > > > > but continue supporting older versions
> of
> > > > Kafka
> > > > > > > > > Connect.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > For now, I've reverted the KIP to the
> > > > previous
> > > > > > > > > iteration
> > > > > > > > > > > > which
> > > > > > > > > > > > > > > > proposed
> > > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > addition of a new `SinkRecord` method
> to
> > > > obtain
> > > > > > the
> > > > > > > > > > > original
> > > > > > > > > > > > > > Kafka
> > > > > > > > > > > > > > > > > topic
> > > > > > > > > > > > > > > > > > > pre-transformation. One thing to note
> is
> > > that
> > > > > > I've
> > > > > > > > > > removed
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > method
> > > > > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > > > > obtaining the original Kafka partition
> > > after
> > > > a
> > > > > > > > cursory
> > > > > > > > > > > search
> > > > > > > > > > > > > > > showed
> > > > > > > > > > > > > > > > > that
> > > > > > > > > > > > > > > > > > > use cases for partition modifying SMTs
> > are
> > > > > > > primarily
> > > > > > > > on
> > > > > > > > > > the
> > > > > > > > > > > > > > source
> > > > > > > > > > > > > > > > > > > connector side.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > > > > Yash
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > On Tue, Nov 1, 2022 at 9:22 PM Chris
> > > Egerton
> > > > > > > > > > > > > > > <chrise@aiven.io.invalid
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > Hi all,
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > I have more comments I'd like to make
> > on
> > > > this
> > > > > > KIP
> > > > > > > > > when
> > > > > > > > > > I
> > > > > > > > > > > > have
> > > > > > > > > > > > > > > time
> > > > > > > > > > > > > > > > > > (sorry
> > > > > > > > > > > > > > > > > > > > for the delay, Yash, and thanks for
> > your
> > > > > > > > patience!),
> > > > > > > > > > but
> > > > > > > > > > > I
> > > > > > > > > > > > > did
> > > > > > > > > > > > > > > want
> > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > > > chime in and say that I'm also not
> sure
> > > > about
> > > > > > > > > > overloading
> > > > > > > > > > > > > > > > > > SinkTask::put.
> > > > > > > > > > > > > > > > > > > I
> > > > > > > > > > > > > > > > > > > > share the concerns about creating an
> > > > > intuitive,
> > > > > > > > > simple
> > > > > > > > > > > API
> > > > > > > > > > > > > that
> > > > > > > > > > > > > > > > Yash
> > > > > > > > > > > > > > > > > > has
> > > > > > > > > > > > > > > > > > > > raised. In addition, this approach
> > > doesn't
> > > > > seem
> > > > > > > > very
> > > > > > > > > > > > > > > > > sustainable--what
> > > > > > > > > > > > > > > > > > do
> > > > > > > > > > > > > > > > > > > > we do if we encounter another case in
> > the
> > > > > > future
> > > > > > > > that
> > > > > > > > > > > would
> > > > > > > > > > > > > > > > warrant a
> > > > > > > > > > > > > > > > > > > > similar solution? We probably don't
> > want
> > > to
> > > > > > > create
> > > > > > > > > > three,
> > > > > > > > > > > > > four,
> > > > > > > > > > > > > > > > etc.
> > > > > > > > > > > > > > > > > > > > overloaded variants of the method,
> each
> > > of
> > > > > > which
> > > > > > > > > would
> > > > > > > > > > > have
> > > > > > > > > > > > > to
> > > > > > > > > > > > > > be
> > > > > > > > > > > > > > > > > > > > implemented by connector developers
> who
> > > > want
> > > > > to
> > > > > > > > both
> > > > > > > > > > > > leverage
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > latest
> > > > > > > > > > > > > > > > > > > > and greatest connector APIs and
> > maintain
> > > > > > > > > compatibility
> > > > > > > > > > > with
> > > > > > > > > > > > > > > connect
> > > > > > > > > > > > > > > > > > > > Clusters running older versions.
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > I haven't been able to flesh this out
> > > into
> > > > a
> > > > > > > design
> > > > > > > > > > worth
> > > > > > > > > > > > > > > > publishing
> > > > > > > > > > > > > > > > > in
> > > > > > > > > > > > > > > > > > > its
> > > > > > > > > > > > > > > > > > > > own KIP yet, but one alternative I've
> > > > pitched
> > > > > > to
> > > > > > > a
> > > > > > > > > few
> > > > > > > > > > > > people
> > > > > > > > > > > > > > > with
> > > > > > > > > > > > > > > > > > > > generally positive interest has been
> to
> > > > > develop
> > > > > > > an
> > > > > > > > > > > official
> > > > > > > > > > > > > > > > > > compatibility
> > > > > > > > > > > > > > > > > > > > library for Connect developers. This
> > > > library
> > > > > > > would
> > > > > > > > be
> > > > > > > > > > > > > released
> > > > > > > > > > > > > > as
> > > > > > > > > > > > > > > > its
> > > > > > > > > > > > > > > > > > own
> > > > > > > > > > > > > > > > > > > > Maven artifact (separate from
> > > connect-api,
> > > > > > > > > > > connect-runtime,
> > > > > > > > > > > > > > etc.)
> > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > would
> > > > > > > > > > > > > > > > > > > > provide a simple, clean interface for
> > > > > > developers
> > > > > > > to
> > > > > > > > > > > > determine
> > > > > > > > > > > > > > > which
> > > > > > > > > > > > > > > > > > > > features are supported by the version
> > of
> > > > the
> > > > > > > > Connect
> > > > > > > > > > > > runtime
> > > > > > > > > > > > > > that
> > > > > > > > > > > > > > > > > their
> > > > > > > > > > > > > > > > > > > > plugin has been deployed onto. Under
> > the
> > > > > hood,
> > > > > > > this
> > > > > > > > > > > library
> > > > > > > > > > > > > > might
> > > > > > > > > > > > > > > > use
> > > > > > > > > > > > > > > > > > > > reflection to determine whether
> > classes,
> > > > > > methods,
> > > > > > > > > etc.
> > > > > > > > > > > are
> > > > > > > > > > > > > > > > available,
> > > > > > > > > > > > > > > > > > but
> > > > > > > > > > > > > > > > > > > > the developer wouldn't have to do
> > > anything
> > > > > more
> > > > > > > > than
> > > > > > > > > > > check
> > > > > > > > > > > > > (for
> > > > > > > > > > > > > > > > > > example)
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > `Features.SINK_TASK_ERRANT_RECORD_REPORTER.enabled()`
> > > > > > > > > > to
> > > > > > > > > > > > know
> > > > > > > > > > > > > > at
> > > > > > > > > > > > > > > > any
> > > > > > > > > > > > > > > > > > > point
> > > > > > > > > > > > > > > > > > > > in the lifetime of their
> connector/task
> > > > > whether
> > > > > > > > that
> > > > > > > > > > > > feature
> > > > > > > > > > > > > is
> > > > > > > > > > > > > > > > > > provided
> > > > > > > > > > > > > > > > > > > by
> > > > > > > > > > > > > > > > > > > > the runtime.
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > One other high-level comment: this
> > > doesn't
> > > > > > > address
> > > > > > > > > > every
> > > > > > > > > > > > > case,
> > > > > > > > > > > > > > > but
> > > > > > > > > > > > > > > > we
> > > > > > > > > > > > > > > > > > > might
> > > > > > > > > > > > > > > > > > > > consider adding an API to "ack" sink
> > > > records.
> > > > > > > This
> > > > > > > > > > could
> > > > > > > > > > > > use
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > > SubmittedRecords class [1] (with some
> > > > slight
> > > > > > > > tweaks)
> > > > > > > > > > > under
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > hood
> > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > > > track the latest-acked offset for
> each
> > > > topic
> > > > > > > > > partition.
> > > > > > > > > > > > This
> > > > > > > > > > > > > > way,
> > > > > > > > > > > > > > > > > > > connector
> > > > > > > > > > > > > > > > > > > > developers won't be responsible for
> > > > tracking
> > > > > > > > offsets
> > > > > > > > > at
> > > > > > > > > > > all
> > > > > > > > > > > > > in
> > > > > > > > > > > > > > > > their
> > > > > > > > > > > > > > > > > > sink
> > > > > > > > > > > > > > > > > > > > tasks (eliminating issues with the
> > > accuracy
> > > > > of
> > > > > > > > > > > > > > > post-transformation
> > > > > > > > > > > > > > > > > > T/P/O
> > > > > > > > > > > > > > > > > > > > sink record information), and they'll
> > > only
> > > > > have
> > > > > > > to
> > > > > > > > > > notify
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > > Connect
> > > > > > > > > > > > > > > > > > > > framework when a record has been
> > > > successfully
> > > > > > > > > > dispatched
> > > > > > > > > > > to
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > external
> > > > > > > > > > > > > > > > > > > > system. This provides a cleaner,
> > > friendlier
> > > > > > API,
> > > > > > > > and
> > > > > > > > > > also
> > > > > > > > > > > > > > enables
> > > > > > > > > > > > > > > > > more
> > > > > > > > > > > > > > > > > > > > fine-grained metrics like the ones
> > > proposed
> > > > > in
> > > > > > > > > KIP-767
> > > > > > > > > > > [2].
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > [1] -
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://github.com/apache/kafka/blob/9ab140d5419d735baae45aff56ffce7f5622744f/connect/runtime/src/main/java/org/apache/kafka/connect/runtime/SubmittedRecords.java
> > > > > > > > > > > > > > > > > > > > [2] -
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-767%3A+Connect+Latency+Metrics
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > Cheers,
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > Chris
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > On Tue, Nov 1, 2022 at 11:21 AM Yash
> > > Mayya
> > > > <
> > > > > > > > > > > > > > yash.mayya@gmail.com
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > Hi Randall,
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > It's been a while for this one but
> > the
> > > > > more I
> > > > > > > > think
> > > > > > > > > > > about
> > > > > > > > > > > > > it,
> > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > more
> > > > > > > > > > > > > > > > > > > I
> > > > > > > > > > > > > > > > > > > > > feel like the current approach
> with a
> > > new
> > > > > > > > > overloaded
> > > > > > > > > > > > > > > > > `SinkTask::put`
> > > > > > > > > > > > > > > > > > > > method
> > > > > > > > > > > > > > > > > > > > > might not be optimal. We're trying
> to
> > > > fix a
> > > > > > > > pretty
> > > > > > > > > > > corner
> > > > > > > > > > > > > > case
> > > > > > > > > > > > > > > > bug
> > > > > > > > > > > > > > > > > > here
> > > > > > > > > > > > > > > > > > > > > (usage of topic mutating SMTs with
> > sink
> > > > > > > > connectors
> > > > > > > > > > that
> > > > > > > > > > > > do
> > > > > > > > > > > > > > > their
> > > > > > > > > > > > > > > > > own
> > > > > > > > > > > > > > > > > > > > offset
> > > > > > > > > > > > > > > > > > > > > tracking) and I'm not sure that
> > > warrants
> > > > a
> > > > > > > change
> > > > > > > > > to
> > > > > > > > > > > > such a
> > > > > > > > > > > > > > > > central
> > > > > > > > > > > > > > > > > > > > > interface method. The new
> > > `SinkTask::put`
> > > > > > > method
> > > > > > > > > just
> > > > > > > > > > > > seems
> > > > > > > > > > > > > > > > > somewhat
> > > > > > > > > > > > > > > > > > > odd
> > > > > > > > > > > > > > > > > > > > > and it may not be very
> understandable
> > > > for a
> > > > > > new
> > > > > > > > > > reader
> > > > > > > > > > > -
> > > > > > > > > > > > I
> > > > > > > > > > > > > > > don't
> > > > > > > > > > > > > > > > > > think
> > > > > > > > > > > > > > > > > > > > this
> > > > > > > > > > > > > > > > > > > > > should be the case for a public
> > > interface
> > > > > > > method.
> > > > > > > > > > > > > > Furthermore,
> > > > > > > > > > > > > > > > even
> > > > > > > > > > > > > > > > > > > with
> > > > > > > > > > > > > > > > > > > > > elaborate documentation in place,
> I'm
> > > not
> > > > > > sure
> > > > > > > if
> > > > > > > > > > it'll
> > > > > > > > > > > > be
> > > > > > > > > > > > > > very
> > > > > > > > > > > > > > > > > > obvious
> > > > > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > > > > most people what the purpose of
> > having
> > > > > these
> > > > > > > two
> > > > > > > > > > `put`
> > > > > > > > > > > > > > methods
> > > > > > > > > > > > > > > is
> > > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > how
> > > > > > > > > > > > > > > > > > > > > they should be used by sink task
> > > > > > > implementations.
> > > > > > > > > > What
> > > > > > > > > > > do
> > > > > > > > > > > > > you
> > > > > > > > > > > > > > > > > think?
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > > > > > > Yash
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > On Mon, Oct 10, 2022 at 9:33 PM
> Yash
> > > > Mayya
> > > > > <
> > > > > > > > > > > > > > > yash.mayya@gmail.com
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > Hi Randall,
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > Thanks a lot for your valuable
> > > feedback
> > > > > so
> > > > > > > far!
> > > > > > > > > > I've
> > > > > > > > > > > > > > updated
> > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > KIP
> > > > > > > > > > > > > > > > > > > > > based
> > > > > > > > > > > > > > > > > > > > > > on our discussion above. Could
> you
> > > > please
> > > > > > > take
> > > > > > > > > > > another
> > > > > > > > > > > > > > look?
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > > > > > > > Yash
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > > On Tue, Oct 4, 2022 at 12:40 AM
> > > Randall
> > > > > > > Hauch <
> > > > > > > > > > > > > > > > rhauch@gmail.com>
> > > > > > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >> On Mon, Oct 3, 2022 at 11:45 AM
> > Yash
> > > > > > Mayya <
> > > > > > > > > > > > > > > > > yash.mayya@gmail.com>
> > > > > > > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >> > Hi Randall,
> > > > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > > > >> > Thanks for elaborating. I
> think
> > > > these
> > > > > > are
> > > > > > > > all
> > > > > > > > > > very
> > > > > > > > > > > > > good
> > > > > > > > > > > > > > > > points
> > > > > > > > > > > > > > > > > > > and I
> > > > > > > > > > > > > > > > > > > > > see
> > > > > > > > > > > > > > > > > > > > > >> > why the overloaded
> > `SinkTask::put`
> > > > > > method
> > > > > > > > is a
> > > > > > > > > > > > cleaner
> > > > > > > > > > > > > > > > > solution
> > > > > > > > > > > > > > > > > > > > > overall.
> > > > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > > > >> > > public void
> > > > > put(Collection<SinkRecord>
> > > > > > > > > > records,
> > > > > > > > > > > > > > > > > > Map<SinkRecord,
> > > > > > > > > > > > > > > > > > > > > >> > TopicPartition>
> > > > > updatedTopicPartitions)
> > > > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > > > >> > I think this should be
> > > > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > > > >> > `public void
> > > > > put(Collection<SinkRecord>
> > > > > > > > > records,
> > > > > > > > > > > > > > > > > Map<SinkRecord,
> > > > > > > > > > > > > > > > > > > > > >> > TopicPartition>
> > > > > > originalTopicPartitions)`
> > > > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > > > >> > instead because the sink
> records
> > > > > > > themselves
> > > > > > > > > have
> > > > > > > > > > > the
> > > > > > > > > > > > > > > updated
> > > > > > > > > > > > > > > > > > topic
> > > > > > > > > > > > > > > > > > > > > >> > partitions (i.e. after all
> > > > > > transformations
> > > > > > > > > have
> > > > > > > > > > > been
> > > > > > > > > > > > > > > > applied)
> > > > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > > > >> KIP
> > > > > > > > > > > > > > > > > > > > > >> > is proposing a way for the
> tasks
> > > to
> > > > be
> > > > > > > able
> > > > > > > > to
> > > > > > > > > > > > access
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > original
> > > > > > > > > > > > > > > > > > > > > topic
> > > > > > > > > > > > > > > > > > > > > >> > partition (i.e. before
> > > > transformations
> > > > > > > have
> > > > > > > > > been
> > > > > > > > > > > > > > applied).
> > > > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >> Sounds good.
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > > > >> > > Of course, if the developer
> > does
> > > > not
> > > > > > > need
> > > > > > > > > > > separate
> > > > > > > > > > > > > > > > methods,
> > > > > > > > > > > > > > > > > > they
> > > > > > > > > > > > > > > > > > > > can
> > > > > > > > > > > > > > > > > > > > > >> > easily have the older `put`
> > method
> > > > > > simply
> > > > > > > > > > delegate
> > > > > > > > > > > > to
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > newer
> > > > > > > > > > > > > > > > > > > > > method.
> > > > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > > > >> > If the developer does not need
> > > > > separate
> > > > > > > > > methods
> > > > > > > > > > > > (i.e.
> > > > > > > > > > > > > > they
> > > > > > > > > > > > > > > > > don't
> > > > > > > > > > > > > > > > > > > > need
> > > > > > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > > > > >> > use this new addition), they
> can
> > > > > simply
> > > > > > > > > continue
> > > > > > > > > > > > > > > > implementing
> > > > > > > > > > > > > > > > > > just
> > > > > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > > > >> > older `put` method right?
> > > > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >> Correct. We should update the
> > > JavaDoc
> > > > of
> > > > > > > both
> > > > > > > > > > > methods
> > > > > > > > > > > > to
> > > > > > > > > > > > > > > make
> > > > > > > > > > > > > > > > > this
> > > > > > > > > > > > > > > > > > > > > clear,
> > > > > > > > > > > > > > > > > > > > > >> and in general how the two
> methods
> > > > > should
> > > > > > > are
> > > > > > > > > used
> > > > > > > > > > > and
> > > > > > > > > > > > > > > should
> > > > > > > > > > > > > > > > be
> > > > > > > > > > > > > > > > > > > > > >> implemented. That can be part of
> > the
> > > > PR,
> > > > > > and
> > > > > > > > the
> > > > > > > > > > KIP
> > > > > > > > > > > > > > doesn't
> > > > > > > > > > > > > > > > > need
> > > > > > > > > > > > > > > > > > > this
> > > > > > > > > > > > > > > > > > > > > >> wording.
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > > > >> > > Finally, this gives us a
> > roadmap
> > > > for
> > > > > > > > > > > *eventually*
> > > > > > > > > > > > > > > > > deprecating
> > > > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > > > >> older
> > > > > > > > > > > > > > > > > > > > > >> > method, once the Connect
> runtime
> > > > > > versions
> > > > > > > > > > without
> > > > > > > > > > > > this
> > > > > > > > > > > > > > > > change
> > > > > > > > > > > > > > > > > > are
> > > > > > > > > > > > > > > > > > > > old
> > > > > > > > > > > > > > > > > > > > > >> > enough.
> > > > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > > > >> > I'm not sure we'd ever want to
> > > > > deprecate
> > > > > > > the
> > > > > > > > > > older
> > > > > > > > > > > > > > method.
> > > > > > > > > > > > > > > > > Most
> > > > > > > > > > > > > > > > > > > > common
> > > > > > > > > > > > > > > > > > > > > >> sink
> > > > > > > > > > > > > > > > > > > > > >> > connector implementations do
> not
> > > do
> > > > > > their
> > > > > > > > own
> > > > > > > > > > > offset
> > > > > > > > > > > > > > > > tracking
> > > > > > > > > > > > > > > > > > with
> > > > > > > > > > > > > > > > > > > > > >> > asynchronous processing and
> will
> > > > > > probably
> > > > > > > > > never
> > > > > > > > > > > > have a
> > > > > > > > > > > > > > > need
> > > > > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > > > >> > additional parameter
> > > > `Map<SinkRecord,
> > > > > > > > > > > > TopicPartition>
> > > > > > > > > > > > > > > > > > > > > >> > originalTopicPartitions` in
> the
> > > > > proposed
> > > > > > > new
> > > > > > > > > > `put`
> > > > > > > > > > > > > > method.
> > > > > > > > > > > > > > > > > These
> > > > > > > > > > > > > > > > > > > > > >> connectors
> > > > > > > > > > > > > > > > > > > > > >> > can continue implementing only
> > the
> > > > > > > existing
> > > > > > > > > > > > > > > `SinkTask::put`
> > > > > > > > > > > > > > > > > > method
> > > > > > > > > > > > > > > > > > > > > which
> > > > > > > > > > > > > > > > > > > > > >> > will be called by the default
> > > > > > > implementation
> > > > > > > > > of
> > > > > > > > > > > the
> > > > > > > > > > > > > > newer
> > > > > > > > > > > > > > > > > > > overloaded
> > > > > > > > > > > > > > > > > > > > > >> `put`
> > > > > > > > > > > > > > > > > > > > > >> > method.
> > > > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >> +1
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > > > >> > > the pre-commit methods use
> the
> > > > same
> > > > > > > > > > > > > > `Map<TopicPartition,
> > > > > > > > > > > > > > > > > > > > > >> > OffsetAndMetadata>
> > currentOffsets`
> > > > > data
> > > > > > > > > > structure
> > > > > > > > > > > > I'm
> > > > > > > > > > > > > > > > > suggesting
> > > > > > > > > > > > > > > > > > > be
> > > > > > > > > > > > > > > > > > > > > >> used.
> > > > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > > > >> > The data structure you're
> > > suggesting
> > > > > be
> > > > > > > used
> > > > > > > > > is
> > > > > > > > > > a
> > > > > > > > > > > > > > > > > > `Map<SinkRecord,
> > > > > > > > > > > > > > > > > > > > > >> > TopicPartition>` which will
> map
> > > > > > > `SinkRecord`
> > > > > > > > > > > objects
> > > > > > > > > > > > > to
> > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > original
> > > > > > > > > > > > > > > > > > > > > >> topic
> > > > > > > > > > > > > > > > > > > > > >> > partition of the corresponding
> > > > > > > > > `ConsumerRecord`
> > > > > > > > > > > > right?
> > > > > > > > > > > > > > To
> > > > > > > > > > > > > > > > > > clarify,
> > > > > > > > > > > > > > > > > > > > > this
> > > > > > > > > > > > > > > > > > > > > >> is
> > > > > > > > > > > > > > > > > > > > > >> > a new data structure that will
> > > need
> > > > to
> > > > > > be
> > > > > > > > > > managed
> > > > > > > > > > > in
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > > > >> `WorkerSinkTask`.
> > > > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >> Ah, you're right. Thanks for the
> > > > > > correction.
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >> Best regards,
> > > > > > > > > > > > > > > > > > > > > >> Randall
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >> > Thanks,
> > > > > > > > > > > > > > > > > > > > > >> > Yash
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >> > On Mon, Oct 3, 2022 at 1:20 AM
> > > > Randall
> > > > > > > > Hauch <
> > > > > > > > > > > > > > > > > rhauch@gmail.com>
> > > > > > > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > > > >> > > Hi, Yash.
> > > > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > > > >> > > I'm not sure I quite
> > understand
> > > > why
> > > > > it
> > > > > > > > would
> > > > > > > > > > be
> > > > > > > > > > > > > > "easier"
> > > > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > > > > > > connector
> > > > > > > > > > > > > > > > > > > > > >> > > > developers to account for
> > > > > > implementing
> > > > > > > > two
> > > > > > > > > > > > > different
> > > > > > > > > > > > > > > > > > > overloaded
> > > > > > > > > > > > > > > > > > > > > >> `put`
> > > > > > > > > > > > > > > > > > > > > >> > > > methods (assuming that
> they
> > > want
> > > > > to
> > > > > > > use
> > > > > > > > > this
> > > > > > > > > > > new
> > > > > > > > > > > > > > > > feature)
> > > > > > > > > > > > > > > > > > > versus
> > > > > > > > > > > > > > > > > > > > > >> using
> > > > > > > > > > > > > > > > > > > > > >> > a
> > > > > > > > > > > > > > > > > > > > > >> > > > try-catch block around
> > > > > `SinkRecord`
> > > > > > > > access
> > > > > > > > > > > > > methods?
> > > > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > > > >> > > Using a try-catch to try
> > around
> > > an
> > > > > API
> > > > > > > > > method
> > > > > > > > > > > that
> > > > > > > > > > > > > > > *might*
> > > > > > > > > > > > > > > > > be
> > > > > > > > > > > > > > > > > > > > there
> > > > > > > > > > > > > > > > > > > > > >> is a
> > > > > > > > > > > > > > > > > > > > > >> > > very unusual thing for most
> > > > > > developers.
> > > > > > > > > > > > > Unfortunately,
> > > > > > > > > > > > > > > > we've
> > > > > > > > > > > > > > > > > > had
> > > > > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > > > > >> > resort
> > > > > > > > > > > > > > > > > > > > > >> > > to this atypical approach
> with
> > > > > Connect
> > > > > > > in
> > > > > > > > > > places
> > > > > > > > > > > > > when
> > > > > > > > > > > > > > > > there
> > > > > > > > > > > > > > > > > > was
> > > > > > > > > > > > > > > > > > > no
> > > > > > > > > > > > > > > > > > > > > >> good
> > > > > > > > > > > > > > > > > > > > > >> > > alternative. We seem to
> > relying
> > > > upon
> > > > > > > > pattern
> > > > > > > > > > > > because
> > > > > > > > > > > > > > > it's
> > > > > > > > > > > > > > > > > > easier
> > > > > > > > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > > > > > > >> us,
> > > > > > > > > > > > > > > > > > > > > >> > > not because it offers a
> better
> > > > > > > experience
> > > > > > > > > for
> > > > > > > > > > > > > > Connector
> > > > > > > > > > > > > > > > > > > > developers.
> > > > > > > > > > > > > > > > > > > > > >> IMO,
> > > > > > > > > > > > > > > > > > > > > >> > if
> > > > > > > > > > > > > > > > > > > > > >> > > there's a practical
> > alternative
> > > > that
> > > > > > > uses
> > > > > > > > > > normal
> > > > > > > > > > > > > > > > development
> > > > > > > > > > > > > > > > > > > > > practices
> > > > > > > > > > > > > > > > > > > > > >> > and
> > > > > > > > > > > > > > > > > > > > > >> > > techniques, then we should
> use
> > > > that
> > > > > > > > > > alternative.
> > > > > > > > > > > > > IIUC,
> > > > > > > > > > > > > > > > there
> > > > > > > > > > > > > > > > > > is
> > > > > > > > > > > > > > > > > > > at
> > > > > > > > > > > > > > > > > > > > > >> least
> > > > > > > > > > > > > > > > > > > > > >> > > one practical alternative
> for
> > > this
> > > > > KIP
> > > > > > > > that
> > > > > > > > > > > would
> > > > > > > > > > > > > not
> > > > > > > > > > > > > > > > > require
> > > > > > > > > > > > > > > > > > > > > >> developers
> > > > > > > > > > > > > > > > > > > > > >> > to
> > > > > > > > > > > > > > > > > > > > > >> > > use the unusual try-catch to
> > > > handle
> > > > > > the
> > > > > > > > case
> > > > > > > > > > > where
> > > > > > > > > > > > > > > methods
> > > > > > > > > > > > > > > > > are
> > > > > > > > > > > > > > > > > > > not
> > > > > > > > > > > > > > > > > > > > > >> found.
> > > > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > > > >> > > I also think having two
> `put`
> > > > > methods
> > > > > > is
> > > > > > > > > > easier
> > > > > > > > > > > > when
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > Connector
> > > > > > > > > > > > > > > > > > > > > >> has to
> > > > > > > > > > > > > > > > > > > > > >> > > do different things for
> > > different
> > > > > > > Connect
> > > > > > > > > > > > runtimes,
> > > > > > > > > > > > > > too.
> > > > > > > > > > > > > > > > One
> > > > > > > > > > > > > > > > > > of
> > > > > > > > > > > > > > > > > > > > > those
> > > > > > > > > > > > > > > > > > > > > >> > > methods is called by newer
> > > Connect
> > > > > > > > runtimes
> > > > > > > > > > with
> > > > > > > > > > > > the
> > > > > > > > > > > > > > new
> > > > > > > > > > > > > > > > > > > behavior,
> > > > > > > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > > > >> > the
> > > > > > > > > > > > > > > > > > > > > >> > > other method is called by an
> > > older
> > > > > > > Connect
> > > > > > > > > > > > runtime.
> > > > > > > > > > > > > Of
> > > > > > > > > > > > > > > > > course,
> > > > > > > > > > > > > > > > > > > if
> > > > > > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > > > >> > > developer does not need
> > separate
> > > > > > > methods,
> > > > > > > > > they
> > > > > > > > > > > can
> > > > > > > > > > > > > > > easily
> > > > > > > > > > > > > > > > > have
> > > > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > > > >> older
> > > > > > > > > > > > > > > > > > > > > >> > > `put` method simply delegate
> > to
> > > > the
> > > > > > > newer
> > > > > > > > > > > method.
> > > > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > > > >> > > Finally, this gives us a
> > roadmap
> > > > for
> > > > > > > > > > > *eventually*
> > > > > > > > > > > > > > > > > deprecating
> > > > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > > > >> older
> > > > > > > > > > > > > > > > > > > > > >> > > method, once the Connect
> > runtime
> > > > > > > versions
> > > > > > > > > > > without
> > > > > > > > > > > > > this
> > > > > > > > > > > > > > > > > change
> > > > > > > > > > > > > > > > > > > are
> > > > > > > > > > > > > > > > > > > > > old
> > > > > > > > > > > > > > > > > > > > > >> > > enough.
> > > > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > > > >> > > I think the advantage of
> going
> > > > with
> > > > > > the
> > > > > > > > > > > > > > > > > > > > > >> > > > proposed approach in the
> KIP
> > > is
> > > > > that
> > > > > > > it
> > > > > > > > > > > wouldn't
> > > > > > > > > > > > > > > require
> > > > > > > > > > > > > > > > > > extra
> > > > > > > > > > > > > > > > > > > > > >> > > book-keeping
> > > > > > > > > > > > > > > > > > > > > >> > > > (the Map<SinkRecord,
> > > > > > > > > > > > > > > > > > > > > >> > > > TopicPartition> in
> > > > > `WorkerSinkTask`
> > > > > > in
> > > > > > > > > your
> > > > > > > > > > > > > proposed
> > > > > > > > > > > > > > > > > > approach)
> > > > > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > > > >> > > The connector does have to
> do
> > > some
> > > > > of
> > > > > > > this
> > > > > > > > > > > > > bookkeeping
> > > > > > > > > > > > > > > in
> > > > > > > > > > > > > > > > > how
> > > > > > > > > > > > > > > > > > > they
> > > > > > > > > > > > > > > > > > > > > >> track
> > > > > > > > > > > > > > > > > > > > > >> > > the topic partition offsets
> > used
> > > > in
> > > > > > the
> > > > > > > > > > > > `preCommit`,
> > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > > > >> pre-commit
> > > > > > > > > > > > > > > > > > > > > >> > > methods use the same
> > > > > > > `Map<TopicPartition,
> > > > > > > > > > > > > > > > OffsetAndMetadata>
> > > > > > > > > > > > > > > > > > > > > >> > > currentOffsets`
> > > > > > > > > > > > > > > > > > > > > >> > > data structure I'm
> suggesting
> > be
> > > > > used.
> > > > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > > > >> > > I hope that helps.
> > > > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > > > >> > > Best regards,
> > > > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > > > >> > > Randall
> > > > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > > > >> > > On Mon, Sep 26, 2022 at 9:38
> > AM
> > > > Yash
> > > > > > > > Mayya <
> > > > > > > > > > > > > > > > > > > yash.mayya@gmail.com>
> > > > > > > > > > > > > > > > > > > > > >> wrote:
> > > > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > > > >> > > > Hi Randall,
> > > > > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > > > > >> > > > Thanks for reviewing the
> > KIP!
> > > > > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > > > > >> > > > > That latter logic can
> get
> > > > quite
> > > > > > > ugly.
> > > > > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > > > > >> > > > I'm not sure I quite
> > > understand
> > > > > why
> > > > > > it
> > > > > > > > > would
> > > > > > > > > > > be
> > > > > > > > > > > > > > > "easier"
> > > > > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > > > > > > >> connector
> > > > > > > > > > > > > > > > > > > > > >> > > > developers to account for
> > > > > > implementing
> > > > > > > > two
> > > > > > > > > > > > > different
> > > > > > > > > > > > > > > > > > > overloaded
> > > > > > > > > > > > > > > > > > > > > >> `put`
> > > > > > > > > > > > > > > > > > > > > >> > > > methods (assuming that
> they
> > > want
> > > > > to
> > > > > > > use
> > > > > > > > > this
> > > > > > > > > > > new
> > > > > > > > > > > > > > > > feature)
> > > > > > > > > > > > > > > > > > > versus
> > > > > > > > > > > > > > > > > > > > > >> using
> > > > > > > > > > > > > > > > > > > > > >> > a
> > > > > > > > > > > > > > > > > > > > > >> > > > try-catch block around
> > > > > `SinkRecord`
> > > > > > > > access
> > > > > > > > > > > > > methods?
> > > > > > > > > > > > > > In
> > > > > > > > > > > > > > > > > both
> > > > > > > > > > > > > > > > > > > > > cases, a
> > > > > > > > > > > > > > > > > > > > > >> > > > connector developer would
> > need
> > > > to
> > > > > > > write
> > > > > > > > > > > > additional
> > > > > > > > > > > > > > > code
> > > > > > > > > > > > > > > > in
> > > > > > > > > > > > > > > > > > > order
> > > > > > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > > > > >> > > ensure
> > > > > > > > > > > > > > > > > > > > > >> > > > that their connector
> > continues
> > > > > > working
> > > > > > > > > with
> > > > > > > > > > > > older
> > > > > > > > > > > > > > > > Connect
> > > > > > > > > > > > > > > > > > > > > runtimes.
> > > > > > > > > > > > > > > > > > > > > >> > > > Furthermore, we would
> > probably
> > > > > need
> > > > > > to
> > > > > > > > > > > carefully
> > > > > > > > > > > > > > > > document
> > > > > > > > > > > > > > > > > > how
> > > > > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > > > >> > > > implementation for the
> older
> > > > `put`
> > > > > > > > method
> > > > > > > > > > > should
> > > > > > > > > > > > > > look
> > > > > > > > > > > > > > > > like
> > > > > > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > > > > > > >> > connectors
> > > > > > > > > > > > > > > > > > > > > >> > > > that want to use this new
> > > > > feature. I
> > > > > > > > think
> > > > > > > > > > the
> > > > > > > > > > > > > > > advantage
> > > > > > > > > > > > > > > > > of
> > > > > > > > > > > > > > > > > > > > going
> > > > > > > > > > > > > > > > > > > > > >> with
> > > > > > > > > > > > > > > > > > > > > >> > > the
> > > > > > > > > > > > > > > > > > > > > >> > > > proposed approach in the
> KIP
> > > is
> > > > > that
> > > > > > > it
> > > > > > > > > > > wouldn't
> > > > > > > > > > > > > > > require
> > > > > > > > > > > > > > > > > > extra
> > > > > > > > > > > > > > > > > > > > > >> > > book-keeping
> > > > > > > > > > > > > > > > > > > > > >> > > > (the Map<SinkRecord,
> > > > > > > > > > > > > > > > > > > > > >> > > > TopicPartition> in
> > > > > `WorkerSinkTask`
> > > > > > in
> > > > > > > > > your
> > > > > > > > > > > > > proposed
> > > > > > > > > > > > > > > > > > approach)
> > > > > > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > > > >> also
> > > > > > > > > > > > > > > > > > > > > >> > > the
> > > > > > > > > > > > > > > > > > > > > >> > > > fact that the try-catch
> > based
> > > > > logic
> > > > > > is
> > > > > > > > an
> > > > > > > > > > > > already
> > > > > > > > > > > > > > > > > > established
> > > > > > > > > > > > > > > > > > > > > >> pattern
> > > > > > > > > > > > > > > > > > > > > >> > > > through
> > > > > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-610%3A+Error+Reporting+in+Sink+Connectors
> > > > > > > > > > > > > > > > > > > > > >> > > > and other KIPs which added
> > > > methods
> > > > > > to
> > > > > > > > > > > > source/sink
> > > > > > > > > > > > > > > > > > > connector/task
> > > > > > > > > > > > > > > > > > > > > >> > > contexts.
> > > > > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > > > > >> > > > Let me know if you still
> > feel
> > > > that
> > > > > > > > having
> > > > > > > > > a
> > > > > > > > > > > new
> > > > > > > > > > > > > > > > overloaded
> > > > > > > > > > > > > > > > > > put
> > > > > > > > > > > > > > > > > > > > > >> method
> > > > > > > > > > > > > > > > > > > > > >> > is
> > > > > > > > > > > > > > > > > > > > > >> > > a
> > > > > > > > > > > > > > > > > > > > > >> > > > cleaner solution and I'd
> be
> > > > happy
> > > > > to
> > > > > > > > > > > reconsider!
> > > > > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > > > > >> > > > Thanks,
> > > > > > > > > > > > > > > > > > > > > >> > > > Yash
> > > > > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > > > > >> > > > On Thu, Sep 22, 2022 at
> > 11:18
> > > PM
> > > > > > > Randall
> > > > > > > > > > > Hauch <
> > > > > > > > > > > > > > > > > > > > rhauch@gmail.com>
> > > > > > > > > > > > > > > > > > > > > >> > wrote:
> > > > > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > > > > >> > > > > Hi, Yash. Thanks for
> > picking
> > > > up
> > > > > > this
> > > > > > > > KIP
> > > > > > > > > > and
> > > > > > > > > > > > > > > > discussion.
> > > > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > > > >> > > > > The KIP includes this
> > > rejected
> > > > > > > > > > alternative:
> > > > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > > > >> > > > > > 4. Update SinkTask.put
> > in
> > > > any
> > > > > > way
> > > > > > > to
> > > > > > > > > > pass
> > > > > > > > > > > > the
> > > > > > > > > > > > > > new
> > > > > > > > > > > > > > > > > > > > information
> > > > > > > > > > > > > > > > > > > > > >> > outside
> > > > > > > > > > > > > > > > > > > > > >> > > > > > SinkRecord (e.g. a Map
> > or
> > > a
> > > > > > > derived
> > > > > > > > > > class)
> > > > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > > > >> > > > > >    -
> > > > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > > > >> > > > > >    Much more
> disruptive
> > > > change
> > > > > > > > without
> > > > > > > > > > > > > > > considerable
> > > > > > > > > > > > > > > > > pros
> > > > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > > > >> > > > > One advantage about
> doing
> > > this
> > > > > is
> > > > > > > that
> > > > > > > > > > sink
> > > > > > > > > > > > > > > connector
> > > > > > > > > > > > > > > > > > > > > >> implementations
> > > > > > > > > > > > > > > > > > > > > >> > > can
> > > > > > > > > > > > > > > > > > > > > >> > > > > more easily implement
> two
> > > > > > different
> > > > > > > > > > > "put(...)"
> > > > > > > > > > > > > > > methods
> > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > > > handle
> > > > > > > > > > > > > > > > > > > > > >> > > running
> > > > > > > > > > > > > > > > > > > > > >> > > > in
> > > > > > > > > > > > > > > > > > > > > >> > > > > a variety of runtimes,
> > > without
> > > > > > > having
> > > > > > > > to
> > > > > > > > > > use
> > > > > > > > > > > > > > > try-catch
> > > > > > > > > > > > > > > > > > logic
> > > > > > > > > > > > > > > > > > > > > >> around
> > > > > > > > > > > > > > > > > > > > > >> > the
> > > > > > > > > > > > > > > > > > > > > >> > > > > newer SinkRecord access
> > > > methods.
> > > > > > > That
> > > > > > > > > > latter
> > > > > > > > > > > > > logic
> > > > > > > > > > > > > > > can
> > > > > > > > > > > > > > > > > get
> > > > > > > > > > > > > > > > > > > > quite
> > > > > > > > > > > > > > > > > > > > > >> > ugly.
> > > > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > > > >> > > > > For example, the
> existing
> > > > `put`
> > > > > > > method
> > > > > > > > > has
> > > > > > > > > > > > this
> > > > > > > > > > > > > > > > > signature:
> > > > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > > > >> > > > > public abstract void
> > > > > > > > > > > > put(Collection<SinkRecord>
> > > > > > > > > > > > > > > > > records);
> > > > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > > > >> > > > > If we added an
> overloaded
> > > > method
> > > > > > > that
> > > > > > > > > > passed
> > > > > > > > > > > > in
> > > > > > > > > > > > > a
> > > > > > > > > > > > > > > map
> > > > > > > > > > > > > > > > of
> > > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > > old
> > > > > > > > > > > > > > > > > > > > > >> > > > > topic+partition for each
> > > > record
> > > > > > (and
> > > > > > > > > > defined
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > > absence
> > > > > > > > > > > > > > > > > > of
> > > > > > > > > > > > > > > > > > > an
> > > > > > > > > > > > > > > > > > > > > >> entry
> > > > > > > > > > > > > > > > > > > > > >> > as
> > > > > > > > > > > > > > > > > > > > > >> > > > > having an unchanged
> topic
> > > and
> > > > > > > > > partition):
> > > > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > > > >> > > > > public void
> > > > > > > put(Collection<SinkRecord>
> > > > > > > > > > > > records,
> > > > > > > > > > > > > > > > > > > > Map<SinkRecord,
> > > > > > > > > > > > > > > > > > > > > >> > > > > TopicPartition>
> > > > > > > > updatedTopicPartitions)
> > > > > > > > > {
> > > > > > > > > > > > > > > > > > > > > >> > > > > put(records);
> > > > > > > > > > > > > > > > > > > > > >> > > > > }
> > > > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > > > >> > > > > then a `SinkTask`
> > > > implementation
> > > > > > > that
> > > > > > > > > > wants
> > > > > > > > > > > to
> > > > > > > > > > > > > use
> > > > > > > > > > > > > > > > this
> > > > > > > > > > > > > > > > > > new
> > > > > > > > > > > > > > > > > > > > > >> feature
> > > > > > > > > > > > > > > > > > > > > >> > > could
> > > > > > > > > > > > > > > > > > > > > >> > > > > simply implement both
> > > methods:
> > > > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > > > >> > > > > public void
> > > > > > > put(Collection<SinkRecord>
> > > > > > > > > > > > records)
> > > > > > > > > > > > > {
> > > > > > > > > > > > > > > > > > > > > >> > > > > // Running in an older
> > > > runtime,
> > > > > so
> > > > > > > no
> > > > > > > > > > > tracking
> > > > > > > > > > > > > of
> > > > > > > > > > > > > > > > > > > SMT-modified
> > > > > > > > > > > > > > > > > > > > > >> topic
> > > > > > > > > > > > > > > > > > > > > >> > > > names
> > > > > > > > > > > > > > > > > > > > > >> > > > > or partitions
> > > > > > > > > > > > > > > > > > > > > >> > > > > put(records, Map.of());
> > > > > > > > > > > > > > > > > > > > > >> > > > > }
> > > > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > > > >> > > > > public void
> > > > > > > put(Collection<SinkRecord>
> > > > > > > > > > > > records,
> > > > > > > > > > > > > > > > > > > > Map<SinkRecord,
> > > > > > > > > > > > > > > > > > > > > >> > > > > TopicPartition>
> > > > > > > > updatedTopicPartitions)
> > > > > > > > > {
> > > > > > > > > > > > > > > > > > > > > >> > > > > // real logic here
> > > > > > > > > > > > > > > > > > > > > >> > > > > }
> > > > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > > > >> > > > > This seems a lot easier
> > than
> > > > > > having
> > > > > > > to
> > > > > > > > > use
> > > > > > > > > > > > > > try-catch
> > > > > > > > > > > > > > > > > > logic,
> > > > > > > > > > > > > > > > > > > > yet
> > > > > > > > > > > > > > > > > > > > > >> still
> > > > > > > > > > > > > > > > > > > > > >> > > > > allows sink connectors
> to
> > > > > utilize
> > > > > > > the
> > > > > > > > > new
> > > > > > > > > > > > > > > > functionality
> > > > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > > > still
> > > > > > > > > > > > > > > > > > > > > >> > work
> > > > > > > > > > > > > > > > > > > > > >> > > > with
> > > > > > > > > > > > > > > > > > > > > >> > > > > older Connect runtimes.
> > > > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > > > >> > > > > WDYT?
> > > > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > > > >> > > > > Randall
> > > > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > > > >> > > > > On Thu, Sep 8, 2022 at
> > 7:03
> > > AM
> > > > > > Yash
> > > > > > > > > Mayya
> > > > > > > > > > <
> > > > > > > > > > > > > > > > > > > > yash.mayya@gmail.com
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > >> > > wrote:
> > > > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > > > >> > > > > > Hi all,
> > > > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > > > >> > > > > > I would like to
> > (re)start
> > > a
> > > > > new
> > > > > > > > > > discussion
> > > > > > > > > > > > > > thread
> > > > > > > > > > > > > > > on
> > > > > > > > > > > > > > > > > > > KIP-793
> > > > > > > > > > > > > > > > > > > > > >> (Kafka
> > > > > > > > > > > > > > > > > > > > > >> > > > > > Connect) which
> proposes
> > > some
> > > > > > > > additions
> > > > > > > > > > to
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > public
> > > > > > > > > > > > > > > > > > > > > SinkRecord
> > > > > > > > > > > > > > > > > > > > > >> > > > interface
> > > > > > > > > > > > > > > > > > > > > >> > > > > > in order to support
> > topic
> > > > > > mutating
> > > > > > > > > SMTs
> > > > > > > > > > > for
> > > > > > > > > > > > > sink
> > > > > > > > > > > > > > > > > > > connectors
> > > > > > > > > > > > > > > > > > > > > >> that do
> > > > > > > > > > > > > > > > > > > > > >> > > > their
> > > > > > > > > > > > > > > > > > > > > >> > > > > > own offset tracking.
> > > > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > > > >> > > > > > Links:
> > > > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > > > >> > > > > > KIP:
> > > > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=191336830
> > > > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > > > >> > > > > > Older discussion
> thread:
> > > > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >
> > > > > > > > > > >
> > > > > https://lists.apache.org/thread/00kcth6057jdcsyzgy1x8nb2s1cymy8h
> > > > > > > > > > > > ,
> > > > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >
> > > > > > > > > > >
> > > > > https://lists.apache.org/thread/rzqkm0q5y5v3vdjhg8wqppxbkw7nyopj
> > > > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > > > >> > > > > > Jira:
> > > > > > > > > > > > > > > > >
> > > > https://issues.apache.org/jira/browse/KAFKA-13431
> > > > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > > > >> > > > > > Thanks,
> > > > > > > > > > > > > > > > > > > > > >> > > > > > Yash
> > > > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
>

Re: [DISCUSS] KIP-793: Sink Connectors: Support topic-mutating SMTs for async connectors (preCommit users)

[Chris Egerton <ch...@aiven.io.INVALID>]

Hi Yash,

Thanks for your continued work on this tricky feature. I have no further
comments or suggestions on the KIP and am ready to vote in favor of it.

That said, I did want to quickly respond to this comment:

> On a side note, this also means that the per sink record ack API
that was proposed earlier wouldn't really work for this case since Kafka
consumers themselves don't support per message acknowledgement semantics
(and any sort of manual book-keeping based on offset linearity in a topic
partition would be affected by things like log compaction, control records
for transactional use cases etc.) right?

I believe we could still use the SubmittedRecords class [1] (with some
small tweaks) to track ack'd messages and the latest-committable offsets
per topic partition, without relying on assumptions about offsets for
consecutive records consumed from Kafka always differing by one. But at
this point I think that, although this approach does come with the
advantage of also enabling fine-grained metrics on record delivery to the
sink system, it's not worth the tradeoff in intuition since it's less clear
why users should prefer that API instead of using SinkTask::preCommit.

[1] -
https://github.com/apache/kafka/blob/12be344fdd3b20f338ccab87933b89049ce202a4/connect/runtime/src/main/java/org/apache/kafka/connect/runtime/SubmittedRecords.java

Cheers,

Chris

On Wed, Jun 21, 2023 at 9:46 AM Yash Mayya <ya...@gmail.com> wrote:

> Hi Chris,
>
> Firstly, thanks for sharing your detailed thoughts on this thorny issue!
> Point taken on Kafka Connect being a brownfield project and I guess we
> might just need to trade off elegant / "clean" interfaces for fixing this
> gap in functionality. Also, thanks for calling out all the existing
> cross-plugin interactions and also the fact that connectors are not and
> should not be developed in silos ignoring the rest of the ecosystem. That
> said, here are my thoughts:
>
> > we could replace these methods with headers that the
> > Connect runtime automatically injects into records directly
> > before dispatching them to SinkTask::put.
>
> Hm, that's an interesting idea to get around the need for connectors to
> handle potential 'NoSuchMethodError's in calls to
> SinkRecord::originalTopic/originalKafkaPartition/originalKafkaOffset.
> However, I'm inclined to agree that retrieving these values from the record
> headers seems even less intuitive and I'm okay with adding this to the
> rejected alternatives list.
>
> > we can consider eliminating the overridden
> > SinkTask::open/close methods
>
> I tried to further explore the idea of keeping just the existing
> SinkTask::open / SinkTask::close methods but only calling them with
> post-transform topic partitions and ended up coming to the same conclusion
> that you did earlier in this thread :)
>
> The overloaded SinkTask::open / SinkTask::close are currently the biggest
> sticking points with the latest iteration of this KIP and I'd prefer this
> elimination for now. The primary reasoning is that the information from
> open / close on pre-transform topic partitions can be combined with the per
> record information of both pre-transform and post-transform topic
> partitions to handle most practical use cases without significantly
> muddying the sink connector related public interfaces. The argument that
> this makes it harder for sink connectors to deal with post-transform topic
> partitions (i.e. in terms of grouping together or batching records for
> writing to the sink system) can be countered with the fact that it'll be
> similarly challenging even with the overloaded method approach of calling
> open / close with both pre-transform and post-transform topic partitions
> since the batching would be done on post-transform topic partitions whereas
> offset tracking and reporting for commits would be done on pre-transform
> topic partitions (and the two won't necessarily serially advance in
> lockstep). On a side note, this also means that the per sink record ack API
> that was proposed earlier wouldn't really work for this case since Kafka
> consumers themselves don't support per message acknowledgement semantics
> (and any sort of manual book-keeping based on offset linearity in a topic
> partition would be affected by things like log compaction, control records
> for transactional use cases etc.) right? Overall, I think that the only
> benefit of the overloaded open / close methods approach is that the
> framework can enable the eventual closure of any post-transform topic
> partition based writers created by sink tasks using the heuristics we
> discussed earlier (via a cache with a time-based eviction policy) which
> doesn't seem worth it at this point.
>
> Thanks,
> Yash
>
> On Mon, May 22, 2023 at 7:30 PM Chris Egerton <ch...@aiven.io.invalid>
> wrote:
>
> > Hi Yash,
> >
> > I've been following the discussion and have some thoughts. Ultimately I'm
> > still in favor of this KIP and would hate to see it go dormant, though we
> > may end up settling for a less-invasive option.
> >
> >
> > On the topic of abstraction and inter-plugin interactions:
> >
> > First, there already are instances of cross-plugin interactions. Logical
> > type handling is probably the biggest example: a source connector embeds
> > metadata in the schema for record keys/values it emits that notifies
> > downstream converters about how to handle them. We provide support for
> some
> > logical types in Connect out of the box, but there's nothing stopping
> > connector and converter developers from implementing their own logical
> type
> > support using the exact same mechanism and different logical type names,
> > which is already done by Debezium, to name one example.
> >
> > Second, although it's been a goal of Connect to abstract away parts of
> > building a data pipeline so that, e.g., connector developers don't have
> to
> > be concerned with converters or consumers, in reality, this layer of
> > abstraction has already been eroded. The example that most-readily comes
> to
> > mind is how source tasks are notified of the offsets of records that
> > they've emitted after they've been published to Kafka via
> > SourceTask::commitRecord [1].
> >
> > But, more importantly, it's unlikely that connectors are being developed
> in
> > complete isolation. Nobody's going to implement the SinkConnector /
> > SinkTask interfaces and then throw that code off to someone else to
> figure
> > out all the details of deployment, configuration, testing, etc.
> Developers
> > will probably have to be aware of at least the converter interface, some
> of
> > the available implementations of it, and some details of Kafka clients
> > (e.g., consumer groups for sink connectors). And this isn't a bad
> > thing--it's unlikely that someone will write a Kafka connector without
> > having or benefitting from some understanding of Kafka and the steps of
> the
> > data pipeline that it will be a part of.
> >
> > Bringing this to the practical topic of discussion--transformations--I
> > think it's actually in everyone's best interests for connector developers
> > to be aware of transformations. This isn't just because of the specific
> > problem that the KIP is trying to address. It's because there's plenty of
> > logic that can be implemented via SMT that a naive connector developer
> will
> > think that they have to implement on their own, which will ultimately
> lead
> > to a sub-par experience for people who end up using those connectors due
> to
> > inconsistent semantics (especially lack of predicates), inconsistent
> > configuration syntax, increased chances for bugs, and FUD ("why wasn't
> this
> > implemented as an SMT?").
> >
> > Finally, although preserving clean, composable interfaces that can be
> > understood in isolation is a great principle to start with, we are now in
> > what Anna McDonald recently referred to as "brownfield" space for
> Connect.
> > We can't go back in time and redesign the SMT interface/contracts to make
> > things cleaner. And I don't think it's fair to anyone to suddenly drop
> > support for SMTs that mutate t/p/o information for sink records,
> especially
> > since these can be used gainfully with plenty of existing sink
> connectors.
> >
> > Ultimately I still think the path forward that's best for the users is to
> > make the impossible possible by addressing this long-standing API gap in
> > Connect. Yes, it adds to the cognitive burden for connector developers,
> but
> > if they can tolerate it, the end result is better for everyone involved,
> > and if they can't, it's likely that the end result will be a preservation
> > of existing behavior, which leaves us no worse than before.
> >
> >
> > With all that said, I've thought about how to minimize or at least hide
> the
> > API changes as much as possible. I've had two thoughts:
> >
> > 1. On the
> > SinkRecord::originalTopic/originalKafkaPartition/originalKafkaOffset
> front,
> > we could replace these methods with headers that the Connect runtime
> > automatically injects into records directly before dispatching them to
> > SinkTask::put. The names can be the proposed method names (e.g.,
> > "originalTopic"). I believe this is inferior to the current proposal and
> > should be a rejected alternative, but it at least seemed worth floating
> in
> > the name of compromise. I dislike this approach for two reasons: first,
> it
> > seems even less intuitive, and second, it doesn't come with the benefit
> of
> > encouraging connector developers to understand the SMT interface and take
> > it into account when designing connectors.
> >
> > 2. Although I'd hate to see the same bookkeeping logic implemented in
> > multiple connectors, we can consider eliminating the overridden
> > SinkTask::open/close methods. A note should be added to both methods
> > clarifying that they are only invoked with the original, pre-transform
> > topic partitions, and developers will be on their own if they want to
> deal
> > with post-transform topic partitions instead. I'm on the fence with this
> > one, but if it's a choice between passing this KIP without modifying
> > SinkTask::open/close, or letting the KIP go dormant, I'd happily choose
> the
> > former.
> >
> > Thanks Yash and Greg for the discussion so far, and apologies for the
> wall
> > of text. Looking forward to your thoughts.
> >
> > Cheers,
> >
> > Chris
> >
> > [1] -
> >
> >
> https://kafka.apache.org/34/javadoc/org/apache/kafka/connect/source/SourceTask.html#commitRecord(org.apache.kafka.connect.source.SourceRecord,org.apache.kafka.clients.producer.RecordMetadata)
> >
> > On Sun, Apr 23, 2023 at 11:20 AM Yash Mayya <ya...@gmail.com>
> wrote:
> >
> > > Hi Greg,
> > >
> > > Thanks for the response and sorry for the late reply.
> > >
> > > > Currently the AK tests have a lot of calls to, for example, new
> > > > SinkRecord(String topic, int partition, Schema keySchema,
> > > > Object key, Schema valueSchema, Object value, long kafkaOffset)
> > > > , a constructor without the original T/P/O values. I assumed that for
> > > > backwards compatibility these constructors would still be usable in
> > > > new runtimes. I imagine that there are also tests in downstream
> > projects
> > > > which make use of these constructors, whenever a Transform,
> Predicate,
> > > > or Task is tested without a corresponding Converter. My question was
> > > > about what values are chosen for the original T/P/O methods when
> these
> > > > constructors are used after an upgrade to the latest connect-api.
> > >
> > > That's a good question - since this should only primarily affect
> testing
> > I
> > > think it should be acceptable to simply use the topic, partition and
> > > kafkaOffset values as the originalTopic, originalKafkaPartition
> > > and originalKafkaOffset?
> > >
> > > > If you inject the original T/P/O only before and after the chain,
> SMTs
> > > > after an SMT which changes the original T/P/O will see whatever the
> > > earlier
> > > > SMT emitted. Is this intentional, or should this be avoided?
> > >
> > > Hmm, this sounds like a misbehaving / badly implemented SMTs since
> there
> > > doesn't seem to be any reasonable situation where an SMT should modify
> a
> > > sink record's original topic / partition / offset data so I'm not in
> > favor
> > > of introducing checks and guards in the framework for this.
> > >
> > > Another point that I've been pondering about is the one you raised
> about
> > > the composability of Connect's plugin ecosystem and the special case
> > > handling we're adding to sink connector plugins to work with certain
> > > transformation plugin types. This really doesn't seem like a good
> > precedent
> > > to be setting / starting (since there don't seem to be any other such
> > > "snowflake" inter-plugin interactions) in my opinion. The alternative
> of
> > > completely managing this in the framework (and only exposing the
> virtual
> > > coordinates to the sink tasks) doesn't seem too appealing either due to
> > the
> > > backward compatibility concerns while maintaining existing support and
> > > functionality such as the possibility of implementing exactly-once
> > > semantics, ability for tasks to rewind consumer offsets arbitrarily
> > (which
> > > might require the introduction of some form of persistence for the
> > physical
> > > <-> virtual coordinate mapping) etc. Unfortunately, even though this
> is a
> > > long standing problem that all of us want to fix, I'm considering
> moving
> > > this KIP into a dormant / inactive state since there doesn't seem to
> be a
> > > design that satisfies all the general principles that the Kafka Connect
> > > framework has striven to uphold.
> > >
> > > Thanks,
> > > Yash
> > >
> > > On Tue, Mar 14, 2023 at 3:31 AM Greg Harris
> <greg.harris@aiven.io.invalid
> > >
> > > wrote:
> > >
> > > > Yash,
> > > >
> > > > > 'm not sure I follow - are you asking about how the tests will be
> > > updated
> > > > post this change or about how upgrades will look like for clusters in
> > > > production?
> > > >
> > > > Currently the AK tests have a lot of calls to, for example, new
> > > > SinkRecord(String topic, int partition, Schema keySchema, Object key,
> > > > Schema valueSchema, Object value, long kafkaOffset), a constructor
> > > without
> > > > the original T/P/O values. I assumed that for backwards compatibility
> > > these
> > > > constructors would still be usable in new runtimes.
> > > > I imagine that there are also tests in downstream projects which make
> > use
> > > > of these constructors, whenever a Transform, Predicate, or Task is
> > tested
> > > > without a corresponding Converter. My question was about what values
> > are
> > > > chosen for the original T/P/O methods when these constructors are
> used
> > > > after an upgrade to the latest connect-api.
> > > >
> > > > > There shouldn't be any difference in behavior here - the framework
> > will
> > > > add
> > > > the original T/P/O metadata to the record after the entire
> > transformation
> > > > chain has been applied and just before sending the record to the task
> > for
> > > > processing. The KIP doesn't propose that transformations themselves
> > > should
> > > > also be able to retrieve original T/P/O information for a sink
> record.
> > > >
> > > > The KIP includes this: "Note that while the record's offset can't be
> > > > modified via the standard SinkRecord::newRecord methods that SMTs are
> > > > expected to use, SinkRecord has public constructors that would allow
> > SMTs
> > > > to return records with modified offsets. This is why the proposed
> > changes
> > > > include a new SinkRecord::originalKafkaOffset method as well."
> > > > In order to use the new or old SinkRecord constructors outside of the
> > > > newRecord methods, SMTs will downcast the previous record and may
> > access
> > > > the original T/P/O methods. They may or may not forward this to the
> > next
> > > > SMT, and they may or may not use it in their own computation.
> > > > Since this is acknowledged as a possible implementation, I was just
> > > asking
> > > > about when one SMT changes the original T/P/O, what should later SMTs
> > and
> > > > predicates see from the original T/P/O methods?
> > > > If you inject the original T/P/O only before and after the chain,
> SMTs
> > > > after an SMT which changes the original T/P/O will see whatever the
> > > earlier
> > > > SMT emitted. Is this intentional, or should this be avoided?
> > > > For existing SMTs use the SinkRecord constructor, either directly or
> > via
> > > > subclasses of ConnectRecord, they will drop the original T/P/O and
> fall
> > > > back to the logic from question (1).
> > > >
> > > > > The rejected alternative basically says that we can't do a
> > > > deterministic mapping from virtual coordinates to physical
> coordinates
> > > > without doing a lot of book-keeping.
> > > >
> > > > I suppose there is a possible implementation of metadata book-keeping
> > > which
> > > > provides a reasonable system of virtual coordinates, it just ended up
> > > > equivalent to hydrating intermediate topics to compute a consistent
> > > record
> > > > ordering. I wasn't convinced by calling it "book-keeping" since i've
> > seen
> > > > that phrase used to disregard much less complicated state management,
> > and
> > > > had to see exactly where that solution becomes unreasonable.
> > > >
> > > > Thanks,
> > > > Greg
> > > >
> > > > On Sun, Mar 12, 2023 at 6:30 AM Yash Mayya <ya...@gmail.com>
> > wrote:
> > > >
> > > > > Hi Greg,
> > > > >
> > > > > Thanks for the detailed review!
> > > > >
> > > > > > What is the expected state/behavior for SinkRecords
> > > > > > which do not have original T/P/O information after the
> > > > > > upgrade? Just browsing, it appears that tests make
> > > > > > extensive use of the existing public SinkRecord
> > > > > > constructors  for both Transformations and Connectors.
> > > > >
> > > > > I'm not sure I follow - are you asking about how the tests will be
> > > > updated
> > > > > post this change or about how upgrades will look like for clusters
> in
> > > > > production? For the latter, we won't have to worry about sink
> records
> > > > > without original T/P/O information at all once a cluster is fully
> > > rolled
> > > > > and we will make it (hopefully) abundantly clear that connectors
> need
> > > to
> > > > > account for missing original T/P/O getter methods if they expect to
> > be
> > > > > deployed on older Connect runtimes.
> > > > >
> > > > > > What is the expected behavior for Transformation
> > > > > > implementations which do not use the newRecord
> > > > > > methods and instead use public SinkRecord constructors?
> > > > > > The KIP mentions this as a justification for the
> > > > > > originalKafkaOffset method, but if existing implementations
> > > > > > are using the existing constructors, those constructors won't
> > > > > > forward the original T/P/O information to later transforms or
> > > > > > the task.
> > > > >
> > > > > There shouldn't be any difference in behavior here - the framework
> > will
> > > > add
> > > > > the original T/P/O metadata to the record after the entire
> > > transformation
> > > > > chain has been applied and just before sending the record to the
> task
> > > for
> > > > > processing. The KIP doesn't propose that transformations themselves
> > > > should
> > > > > also be able to retrieve original T/P/O information for a sink
> > record.
> > > > >
> > > > > > This reasoning and the KIP design seems to imply that the
> > > > > > connector is better equipped to solve this problem than the
> > > > > > framework, but the stated reasons are not convincing for me.
> > > > >
> > > > > This was added to the KIP by the original author, but I don't think
> > the
> > > > > intention was to imply that the connector is better equipped to
> solve
> > > > this
> > > > > problem than the framework. The intention is to provide complete
> > > > > information to the connector ("physical" and "virtual coordinates"
> > > > instead
> > > > > of the currently incomplete "virtual coordinates" as you've termed
> > it)
> > > so
> > > > > that connectors can use the virtual coordinates for writing data to
> > the
> > > > > sink system and physical coordinates for offset reporting back to
> the
> > > > > framework. The rejected alternative basically says that we can't
> do a
> > > > > deterministic mapping from virtual coordinates to physical
> > coordinates
> > > > > without doing a lot of book-keeping.
> > > > >
> > > > > I agree with the rest of your analysis on the tradeoffs between the
> > > > > proposed approach versus the seemingly more attractive approach of
> > > > handling
> > > > > everything purely in the framework and only exposing "virtual
> > > > coordinates"
> > > > > to the connectors. I think the biggest thorn here is maintaining
> > > backward
> > > > > compatibility with the considerable ecosystem of existing
> connectors
> > > > which
> > > > > is something Connect has always been burdened by.
> > > > >
> > > > > Thanks,
> > > > > Yash
> > > > >
> > > > > On Wed, Mar 8, 2023 at 6:54 AM Greg Harris
> > > <greg.harris@aiven.io.invalid
> > > > >
> > > > > wrote:
> > > > >
> > > > > > Hi Yash,
> > > > > >
> > > > > > I always use this issue as an example of a bug being caused by
> > design
> > > > > > rather than by implementation error, and once it's fixed I'll
> need
> > to
> > > > > find
> > > > > > something else to talk about :)
> > > > > > So glad to see this get fixed!
> > > > > >
> > > > > > I'll chime in to support some of the earlier discussions that
> seem
> > to
> > > > > have
> > > > > > been resolved:
> > > > > >
> > > > > > 1. With respect to SinkRecord methods vs an overloaded put(): I
> > agree
> > > > > with
> > > > > > the current design but I justify it a little bit differently than
> > has
> > > > > > already been discussed.
> > > > > > If we were designing this interface on day 1 without backwards
> > > > > > compatibility in mind, which design would make more sense? Or
> for a
> > > > > > different framing: In the future when old runtimes and connectors
> > are
> > > > > > retired and the old interfaces are removed, which design is going
> > to
> > > > look
> > > > > > more strange and unmotivated?
> > > > > > Applied to this design decision, I would say that the original
> > T/P/O
> > > > are
> > > > > > properties of a single SinkRecord and make sense as getters, and
> it
> > > > would
> > > > > > be strange to store them in an auxiliary map.
> > > > > >
> > > > > > 2. Following up this change with a compatibility library to make
> > the
> > > > > > interface easier to use is the right choice to make here. This
> > change
> > > > > > should be focused on correctness in allowing developers to fix
> the
> > > > > > incompatibility and we can be concerned with coming up with a
> more
> > > > > > ergonomic solution in the compatibility library.
> > > > > > The API should be focused on generality, correctness, and
> > performance
> > > > > > because those cannot be worked-around after the fact. Connector
> > > > > > implementations and/or libraries can be concerned with trading
> off
> > > some
> > > > > > generality and/or performance for ease-of-use.
> > > > > >
> > > > > > 3. I think that the difference in behavior of the new open/close
> > > > methods
> > > > > as
> > > > > > compared to the old methods is significant, and requires good
> > > > > documentation
> > > > > > to help connector developers avoid lazy and incorrect
> migrations. I
> > > am
> > > > > > happy to have that addressed in code review after the KIP is
> > > approved.
> > > > > >
> > > > > > I had some questions:
> > > > > >
> > > > > > 4. What is the expected state/behavior for SinkRecords which do
> not
> > > > have
> > > > > > original T/P/O information after the upgrade? Just browsing, it
> > > appears
> > > > > > that tests make extensive use of the existing public SinkRecord
> > > > > > constructors for both Transformations and Connectors.
> > > > > >
> > > > > > 5. What is the expected behavior for Transformation
> implementations
> > > > which
> > > > > > do not use the newRecord methods and instead use public
> SinkRecord
> > > > > > constructors? The KIP mentions this as a justification for the
> > > > > > originalKafkaOffset method, but if existing implementations are
> > using
> > > > the
> > > > > > existing constructors, those constructors won't forward the
> > original
> > > > > T/P/O
> > > > > > information to later transforms or the task.
> > > > > >
> > > > > > For the last few points, I want to discuss this rejected
> > alternative:
> > > > > >
> > > > > > > Address the offsets problem entirely within the framework,
> doing
> > > some
> > > > > > kind of mapping from the transformed topic back to the original
> > > topic.
> > > > > > > * This would only work in the cases where there’s no overlap
> > > between
> > > > > the
> > > > > > transformed topic names, but would break for the rest of the
> > > > > > transformations (e.g. static transformation, topic = “a”).
> > > > > > > * Even if we wanted to limit the support to those cases, it
> would
> > > > > require
> > > > > > considerable bookkeeping to add a validation to verify that the
> > > > > > transformation chain adheres to that expectation (and fail fast
> if
> > it
> > > > > > doesn’t).
> > > > > >
> > > > > > 6. This reasoning and the KIP design seems to imply that the
> > > connector
> > > > is
> > > > > > better equipped to solve this problem than the framework, but the
> > > > stated
> > > > > > reasons are not convincing for me.
> > > > > > * A static transformation still causes an offset collision in the
> > > > > connector
> > > > > > * The connector is not permitted to see the transformation chain
> to
> > > do
> > > > > any
> > > > > > fail-fast assertions
> > > > > >
> > > > > > Suppose we were to think of the records at the end of the
> > > > transformation
> > > > > > chain as being in "virtual partitions" with "virtual offsets".
> > > > > > For example, with identity-routing SMTs, the virtual coordinates
> > are
> > > > > > exactly the same as the underlying physical coordinates. For 1-1
> > > > renames,
> > > > > > each virtual topic would be the renamed topic corresponding to
> the
> > > > > > underlying topic. For fan-out from one topic to multiple virtual
> > > > topics,
> > > > > > virtual offsets would use the underlying kafka offsets with gaps
> > for
> > > > > > records going to other virtual partitions. Virtual topics with
> > > dropped
> > > > > > records have similar gaps in the offsets.
> > > > > > Currently, these virtual coordinates are passed into the
> connector
> > > via
> > > > > > SinkTask::put, but SinkTask::open/close/preCommit and
> > > > > > SinkTaskContext::assignment/offsets/pause/resume all use physical
> > > > > > coordinates.
> > > > > > This proposal patches put,open, and close to have both physical
> and
> > > > > virtual
> > > > > > coordinates, but leaves the other methods with physical
> > coordinates.
> > > > > After
> > > > > > this proposal, connectors would be intentionally made aware of
> the
> > > > > > distinction between physical and virtual coordinates, and manage
> > > their
> > > > > own
> > > > > > bookkeeping for the two systems.
> > > > > >
> > > > > > To avoid that connector logic, we could use virtual coordinates
> in
> > > all
> > > > > > connector calls, never revealing that they are different from the
> > > > > physical
> > > > > > coordinates. There's a whole design shopping list that we'd need:
> > > > > > * Renumbering mechanism for disambiguating and making virtual
> > offsets
> > > > > > monotonic in the case of topic/partition collisions
> > > > > > * Data structure and strategy for translating virtual offsets
> back
> > to
> > > > > > physical offsets
> > > > > > * New limits on SinkTaskContext::offsets() calls to prevent
> > rewinding
> > > > > > before the latest commit
> > > > > > * Backwards compatibility and upgrade design
> > > > > >
> > > > > > 7. This alternative was very appealing to me, because the
> strength
> > > of a
> > > > > > plugin framework is the composability of different components.
> > Among
> > > a
> > > > > > collection of N connectors and M transforms, it should ideally
> only
> > > > take
> > > > > > N + M work to understand how the components combine to build the
> > > whole.
> > > > > > However, once you start adding special cases to some plugins to
> > > support
> > > > > > interactions with others, the whole system can take N * M work to
> > > > > > understand. From a complexity standpoint, it would be very good
> for
> > > the
> > > > > > framework to solve this in a way which was connector-agnostic.
> > > > > > The current design compromises the logical isolation of the
> plugins
> > > > > > slightly, but they can collapse offsets very memory-efficiently,
> > and
> > > > > re-use
> > > > > > the existing raw coordinate functions and keep everything else
> > > > backwards
> > > > > > compatible. After deriving all of the above, I think that's a
> > > > reasonable
> > > > > > tradeoff to make.
> > > > > >
> > > > > > Thanks,
> > > > > > Greg
> > > > > >
> > > > > > On Tue, Feb 21, 2023 at 10:17 AM Chris Egerton
> > > <chrise@aiven.io.invalid
> > > > >
> > > > > > wrote:
> > > > > >
> > > > > > > Hi Yash,
> > > > > > >
> > > > > > > We'll probably want to make a few tweaks to the Javadocs for
> the
> > > new
> > > > > > > methods (I'm imagining that notes on compatibility with older
> > > > versions
> > > > > > will
> > > > > > > be required), but I believe what's proposed in the KIP is good
> > > enough
> > > > > to
> > > > > > > approve with the understanding that it may not exactly match
> what
> > > > gets
> > > > > > > implemented/merged.
> > > > > > >
> > > > > > > LGTM, thanks again for the KIP!
> > > > > > >
> > > > > > > Cheers,
> > > > > > >
> > > > > > > Chris
> > > > > > >
> > > > > > > On Tue, Feb 21, 2023 at 12:18 PM Yash Mayya <
> > yash.mayya@gmail.com>
> > > > > > wrote:
> > > > > > >
> > > > > > > > Hi Chris,
> > > > > > > >
> > > > > > > > > we might try to introduce a framework-level configuration
> > > > > > > > > property to dictate which of the pre-transform and
> > > post-transform
> > > > > > > > > topic partitions are used for the fallback call to the
> > > single-arg
> > > > > > > > > variant if a task class has not overridden the multi-arg
> > > variant
> > > > > > > >
> > > > > > > > Thanks for the explanation and I agree that this will be a
> tad
> > > bit
> > > > > too
> > > > > > > > convoluted. :)
> > > > > > > >
> > > > > > > > Please do let me know if you'd like any further amendments to
> > the
> > > > > KIP!
> > > > > > > >
> > > > > > > > Thanks,
> > > > > > > > Yash
> > > > > > > >
> > > > > > > > On Tue, Feb 21, 2023 at 8:42 PM Chris Egerton
> > > > > <chrise@aiven.io.invalid
> > > > > > >
> > > > > > > > wrote:
> > > > > > > >
> > > > > > > > > Hi Yash,
> > > > > > > > >
> > > > > > > > > I think the use case for pre-transform TPO coordinates (and
> > > topic
> > > > > > > > partition
> > > > > > > > > writers created/destroyed in close/open) tends to boil down
> > to
> > > > > > > > exactly-once
> > > > > > > > > semantics, where it's desirable to preserve the guarantees
> > that
> > > > > Kafka
> > > > > > > > > provides (every record has a unique TPO trio, and records
> are
> > > > > ordered
> > > > > > > by
> > > > > > > > > offset within a topic partition).
> > > > > > > > >
> > > > > > > > > It's my understanding that this approach is utilized in
> > several
> > > > > > > > connectors
> > > > > > > > > out there today, and it might break these connectors to
> start
> > > > using
> > > > > > the
> > > > > > > > > post-transform topic partitions automatically in their
> > > open/close
> > > > > > > > methods.
> > > > > > > > >
> > > > > > > > > If we want to get really fancy with this and try to obviate
> > or
> > > at
> > > > > > least
> > > > > > > > > reduce the need for per-connector code changes, we might
> try
> > to
> > > > > > > > introduce a
> > > > > > > > > framework-level configuration property to dictate which of
> > the
> > > > > > > > > pre-transform and post-transform topic partitions are used
> > for
> > > > the
> > > > > > > > fallback
> > > > > > > > > call to the single-arg variant if a task class has not
> > > overridden
> > > > > the
> > > > > > > > > multi-arg variant. But I think this is going a bit too far
> > and
> > > > > would
> > > > > > > > prefer
> > > > > > > > > to keep things simple(r) for now.
> > > > > > > > >
> > > > > > > > > Cheers,
> > > > > > > > >
> > > > > > > > > Chris
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > On Sun, Feb 19, 2023 at 2:34 AM Yash Mayya <
> > > yash.mayya@gmail.com
> > > > >
> > > > > > > wrote:
> > > > > > > > >
> > > > > > > > > > Hi Chris,
> > > > > > > > > >
> > > > > > > > > > > I was actually envisioning something like `void
> > > > > > > > > > > open(Collection<TopicPartition> originalPartitions,
> > > > > > > > > > > Collection<TopicPartition> transformedPartitions)`
> > > > > > > > > >
> > > > > > > > > > Ah okay, this does make a lot more sense. Sorry, I think
> I
> > > > > > > > misunderstood
> > > > > > > > > > you earlier. I do agree with you that this seems better
> > than
> > > > > > > splitting
> > > > > > > > it
> > > > > > > > > > off into two new sets of open / close methods from a
> > > complexity
> > > > > > > > > standpoint.
> > > > > > > > > >
> > > > > > > > > > > Plus, if a connector is intentionally designed to use
> > > > > > > > > > > pre-transformation topic partitions in its open/close
> > > > > > > > > > > methods, wouldn't we just be trading one form of the
> > > > > > > > > > >  problem for another by making this switch?
> > > > > > > > > >
> > > > > > > > > > On thinking about this a bit more, I'm not so convinced
> > that
> > > we
> > > > > > need
> > > > > > > to
> > > > > > > > > > expose the pre-transform / original topic partitions in
> the
> > > new
> > > > > > open
> > > > > > > /
> > > > > > > > > > close methods. The purpose of the open / close methods is
> > to
> > > > > allow
> > > > > > > sink
> > > > > > > > > > tasks to allocate and deallocate resources for each topic
> > > > > partition
> > > > > > > > > > assigned to the task and the purpose of topic-mutating
> SMTs
> > > is
> > > > to
> > > > > > > > > > essentially modify the source topic name from the point
> of
> > > view
> > > > > of
> > > > > > > the
> > > > > > > > > sink
> > > > > > > > > > connector. Why would a sink connector ever need to or
> want
> > to
> > > > > > > allocate
> > > > > > > > > > resources for pre-transform topic partitions? Is the
> > argument
> > > > > here
> > > > > > > that
> > > > > > > > > > since we'll be exposing both the pre-transform and
> > > > post-transform
> > > > > > > topic
> > > > > > > > > > partitions per record, we should also expose the same
> info
> > > via
> > > > > > open /
> > > > > > > > > close
> > > > > > > > > > and allow sink connector implementations to disregard
> > > > > > topic-mutating
> > > > > > > > SMTs
> > > > > > > > > > completely if they wanted to?
> > > > > > > > > >
> > > > > > > > > > Either way, I've gone ahead and updated the KIP to
> reflect
> > > all
> > > > of
> > > > > > > > > > our previous discussion here since it had become quite
> > > > outdated.
> > > > > > I've
> > > > > > > > > also
> > > > > > > > > > updated the KIP title from "Sink Connectors: Support
> > > > > topic-mutating
> > > > > > > > SMTs
> > > > > > > > > > for async connectors (preCommit users)" to "Allow sink
> > > > connectors
> > > > > > to
> > > > > > > be
> > > > > > > > > > used with topic-mutating SMTs" since the improvements to
> > the
> > > > > open /
> > > > > > > > close
> > > > > > > > > > mechanism doesn't pertain only to asynchronous sink
> > > connectors.
> > > > > The
> > > > > > > new
> > > > > > > > > KIP
> > > > > > > > > > URL is:
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-793%3A+Allow+sink+connectors+to+be+used+with+topic-mutating+SMTs
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > Thanks,
> > > > > > > > > > Yash
> > > > > > > > > >
> > > > > > > > > > On Tue, Feb 14, 2023 at 11:39 PM Chris Egerton
> > > > > > > <chrise@aiven.io.invalid
> > > > > > > > >
> > > > > > > > > > wrote:
> > > > > > > > > >
> > > > > > > > > > > Hi Yash,
> > > > > > > > > > >
> > > > > > > > > > > I was actually envisioning something like `void
> > > > > > > > > > > open(Collection<TopicPartition>
> > > > > > > > > > > originalPartitions, Collection<TopicPartition>
> > > > > > > > transformedPartitions)`,
> > > > > > > > > > > since we already convert and transform each batch of
> > > records
> > > > > that
> > > > > > > we
> > > > > > > > > poll
> > > > > > > > > > > from the sink task's consumer en masse, meaning we
> could
> > > > > discover
> > > > > > > > > several
> > > > > > > > > > > new transformed partitions in between consecutive calls
> > to
> > > > > > > > > SinkTask::put.
> > > > > > > > > > >
> > > > > > > > > > > It's also worth noting that we'll probably want to
> > > deprecate
> > > > > the
> > > > > > > > > existing
> > > > > > > > > > > open/close methods, at which point keeping one
> > > non-deprecated
> > > > > > > variant
> > > > > > > > > of
> > > > > > > > > > > each seems more appealing and less complex than keeping
> > > two.
> > > > > > > > > > >
> > > > > > > > > > > Honestly though, I think we're both on the same page
> > enough
> > > > > that
> > > > > > I
> > > > > > > > > > wouldn't
> > > > > > > > > > > object to either approach. We've probably reached the
> > > > > saturation
> > > > > > > > point
> > > > > > > > > > for
> > > > > > > > > > > ROI here and as long as we provide developers a way to
> > get
> > > > the
> > > > > > > > > > information
> > > > > > > > > > > they need from the runtime and take care to add
> Javadocs
> > > and
> > > > > > update
> > > > > > > > our
> > > > > > > > > > > docs page (possibly including the connector development
> > > > > > > quickstart),
> > > > > > > > it
> > > > > > > > > > > should be fine.
> > > > > > > > > > >
> > > > > > > > > > > At this point, it might be worth updating the KIP based
> > on
> > > > > recent
> > > > > > > > > > > discussion so that others can see the latest proposal,
> > and
> > > we
> > > > > can
> > > > > > > > both
> > > > > > > > > > take
> > > > > > > > > > > a look and make sure everything looks good enough
> before
> > > > > opening
> > > > > > a
> > > > > > > > vote
> > > > > > > > > > > thread.
> > > > > > > > > > >
> > > > > > > > > > > Finally, I think you make a convincing case for a
> > > time-based
> > > > > > > eviction
> > > > > > > > > > > policy. I wasn't thinking about the fairly common SMT
> > > pattern
> > > > > of
> > > > > > > > > > deriving a
> > > > > > > > > > > topic name from, e.g., a record field or header.
> > > > > > > > > > >
> > > > > > > > > > > Cheers,
> > > > > > > > > > >
> > > > > > > > > > > Chris
> > > > > > > > > > >
> > > > > > > > > > > On Tue, Feb 14, 2023 at 11:42 AM Yash Mayya <
> > > > > > yash.mayya@gmail.com>
> > > > > > > > > > wrote:
> > > > > > > > > > >
> > > > > > > > > > > > Hi Chris,
> > > > > > > > > > > >
> > > > > > > > > > > > > Plus, if a connector is intentionally designed to
> > > > > > > > > > > > > use pre-transformation topic partitions in its
> > > > > > > > > > > > > open/close methods, wouldn't we just be trading
> > > > > > > > > > > > > one form of the problem for another by making this
> > > > > > > > > > > > > switch?
> > > > > > > > > > > >
> > > > > > > > > > > > Thanks, this makes sense, and given that the KIP
> > already
> > > > > > > proposes a
> > > > > > > > > way
> > > > > > > > > > > for
> > > > > > > > > > > > sink connector implementations to distinguish between
> > > > > > > pre-transform
> > > > > > > > > and
> > > > > > > > > > > > post-transform topics per record, I think I'm
> convinced
> > > > that
> > > > > > > going
> > > > > > > > > with
> > > > > > > > > > > new
> > > > > > > > > > > > `open()` / `close()` methods is the right approach.
> > > > However,
> > > > > I
> > > > > > > > still
> > > > > > > > > > feel
> > > > > > > > > > > > like having overloaded methods will make it a lot
> less
> > > > > > > unintuitive
> > > > > > > > > > given
> > > > > > > > > > > > that the two sets of methods would be different in
> > terms
> > > of
> > > > > > when
> > > > > > > > > > they're
> > > > > > > > > > > > called and what arguments they are passed (also I'm
> > > > presuming
> > > > > > > that
> > > > > > > > > the
> > > > > > > > > > > > overloaded methods you're prescribing will only have
> a
> > > > single
> > > > > > > > > > > > `TopicPartition` rather than a
> > > `Collection<TopicPartition>`
> > > > > as
> > > > > > > > their
> > > > > > > > > > > > parameters). I guess my concern is largely around the
> > > fact
> > > > > that
> > > > > > > it
> > > > > > > > > > won't
> > > > > > > > > > > be
> > > > > > > > > > > > possible to distinguish between the overloaded
> methods'
> > > use
> > > > > > cases
> > > > > > > > > just
> > > > > > > > > > > from
> > > > > > > > > > > > the method signatures. I agree that naming is going
> to
> > be
> > > > > > > difficult
> > > > > > > > > > here,
> > > > > > > > > > > > but I think that having two sets of
> > `SinkTask::openXyz` /
> > > > > > > > > > > > `SinkTask::closeXyz` methods will be less complicated
> > to
> > > > > > > understand
> > > > > > > > > > from
> > > > > > > > > > > a
> > > > > > > > > > > > connector developer perspective (as compared to
> > > overloaded
> > > > > > > methods
> > > > > > > > > with
> > > > > > > > > > > > only differing documentation). Of your suggested
> > > options, I
> > > > > > think
> > > > > > > > > > > > `openPreTransform` / `openPostTransform` are the most
> > > > > > > > comprehensible
> > > > > > > > > > > ones.
> > > > > > > > > > > >
> > > > > > > > > > > > > BTW, I wouldn't say that we can't make assumptions
> > > > > > > > > > > > > about the relationships between pre- and
> > > > > post-transformation
> > > > > > > > > > > > >  topic partitions.
> > > > > > > > > > > >
> > > > > > > > > > > > I meant that the framework wouldn't be able to
> > > > > > deterministically
> > > > > > > > know
> > > > > > > > > > > when
> > > > > > > > > > > > to close a post-transform topic partition given that
> > SMTs
> > > > > could
> > > > > > > use
> > > > > > > > > > > > per-record data / metadata to manipulate the topic
> > names
> > > as
> > > > > and
> > > > > > > how
> > > > > > > > > > > > required (which supports the suggestion to use an
> > > eviction
> > > > > > policy
> > > > > > > > > based
> > > > > > > > > > > > mechanism to call SinkTask::close for post-transform
> > > topic
> > > > > > > > > partitions).
> > > > > > > > > > > >
> > > > > > > > > > > > > We might utilize a policy that assumes a
> > deterministic
> > > > > > > > > > > > > mapping from the former to the latter, for example.
> > > > > > > > > > > >
> > > > > > > > > > > > Wouldn't this be making the assumption that SMTs only
> > use
> > > > the
> > > > > > > topic
> > > > > > > > > > name
> > > > > > > > > > > > itself and no other data / metadata while computing
> the
> > > new
> > > > > > topic
> > > > > > > > > name?
> > > > > > > > > > > Are
> > > > > > > > > > > > you suggesting that since this assumption could work
> > for
> > > a
> > > > > > > majority
> > > > > > > > > of
> > > > > > > > > > > > SMTs, it might be more efficient overall in terms of
> > > > reducing
> > > > > > the
> > > > > > > > > > number
> > > > > > > > > > > of
> > > > > > > > > > > > "false-positive" calls to
> > `SinkTask::closePostTransform`
> > > > (and
> > > > > > > we'll
> > > > > > > > > > also
> > > > > > > > > > > be
> > > > > > > > > > > > able to call `SinkTask::closePostTransform`
> immediately
> > > > after
> > > > > > > topic
> > > > > > > > > > > > partitions are revoked from the consumer)? I was
> > thinking
> > > > > > > something
> > > > > > > > > > more
> > > > > > > > > > > > generic along the lines of a simple time based
> eviction
> > > > > policy
> > > > > > > that
> > > > > > > > > > > > wouldn't be making any assumptions regarding the SMT
> > > > > > > > implementations.
> > > > > > > > > > > > Either way, I do like your earlier suggestion of
> > keeping
> > > > this
> > > > > > > logic
> > > > > > > > > > > > internal and not painting ourselves into a corner by
> > > > > promising
> > > > > > > any
> > > > > > > > > > > > particular behavior in the KIP.
> > > > > > > > > > > >
> > > > > > > > > > > > Thanks,
> > > > > > > > > > > > Yash
> > > > > > > > > > > >
> > > > > > > > > > > > On Tue, Feb 14, 2023 at 1:08 AM Chris Egerton
> > > > > > > > > <chrise@aiven.io.invalid
> > > > > > > > > > >
> > > > > > > > > > > > wrote:
> > > > > > > > > > > >
> > > > > > > > > > > > > Hi Yash,
> > > > > > > > > > > > >
> > > > > > > > > > > > > I think the key difference between adding
> > > > methods/overloads
> > > > > > > > related
> > > > > > > > > > to
> > > > > > > > > > > > > SinkTask::open/SinkTask::close and SinkTask::put is
> > > that
> > > > > this
> > > > > > > > isn't
> > > > > > > > > > > > > auxiliary information that may or may not be useful
> > to
> > > > > > > connector
> > > > > > > > > > > > > developers. It's actually critical for them to
> > > understand
> > > > > the
> > > > > > > > > > > difference
> > > > > > > > > > > > > between the two concepts here, even if they look
> very
> > > > > > similar.
> > > > > > > > And
> > > > > > > > > > > yes, I
> > > > > > > > > > > > > do believe that switching from pre-transform to
> > > > > > post-transform
> > > > > > > > > topic
> > > > > > > > > > > > > partitions is too big a change in behavior here.
> > Plus,
> > > > if a
> > > > > > > > > connector
> > > > > > > > > > > is
> > > > > > > > > > > > > intentionally designed to use pre-transformation
> > topic
> > > > > > > partitions
> > > > > > > > > in
> > > > > > > > > > > its
> > > > > > > > > > > > > open/close methods, wouldn't we just be trading one
> > > form
> > > > of
> > > > > > the
> > > > > > > > > > problem
> > > > > > > > > > > > for
> > > > > > > > > > > > > another by making this switch?
> > > > > > > > > > > > >
> > > > > > > > > > > > > One possible alternative to overloading the
> existing
> > > > > methods
> > > > > > is
> > > > > > > > to
> > > > > > > > > > > split
> > > > > > > > > > > > > SinkTask::open into openOriginal (or possibly
> > > > openPhysical
> > > > > or
> > > > > > > > > > > > > openPreTransform) and openTransformed (or
> openLogical
> > > or
> > > > > > > > > > > > > openPostTransform), with a similar change for
> > > > > > SinkTask::close.
> > > > > > > > The
> > > > > > > > > > > > default
> > > > > > > > > > > > > implementation for SinkTask::openOriginal can be to
> > > call
> > > > > > > > > > > SinkTask::open,
> > > > > > > > > > > > > and the same can go for SinkTask::close. However, I
> > > > prefer
> > > > > > > > > > overloading
> > > > > > > > > > > > the
> > > > > > > > > > > > > existing methods since this alternative increases
> > > > > complexity
> > > > > > > and
> > > > > > > > > none
> > > > > > > > > > > of
> > > > > > > > > > > > > the names are very informative.
> > > > > > > > > > > > >
> > > > > > > > > > > > > BTW, I wouldn't say that we can't make assumptions
> > > about
> > > > > the
> > > > > > > > > > > > relationships
> > > > > > > > > > > > > between pre- and post-transformation topic
> > partitions.
> > > We
> > > > > > might
> > > > > > > > > > > utilize a
> > > > > > > > > > > > > policy that assumes a deterministic mapping from
> the
> > > > former
> > > > > > to
> > > > > > > > the
> > > > > > > > > > > > latter,
> > > > > > > > > > > > > for example. The distinction I'd draw is that the
> > > > > assumptions
> > > > > > > we
> > > > > > > > > make
> > > > > > > > > > > can
> > > > > > > > > > > > > and probably should favor some cases in terms of
> > > > > performance
> > > > > > > > (i.e.,
> > > > > > > > > > > > > reducing the number of unnecessary calls to
> > close/open
> > > > > over a
> > > > > > > > given
> > > > > > > > > > > sink
> > > > > > > > > > > > > task's lifetime), but should not lead to guaranteed
> > > > > resource
> > > > > > > > leaks
> > > > > > > > > or
> > > > > > > > > > > > > failure to obey API contract in any cases.
> > > > > > > > > > > > >
> > > > > > > > > > > > > Cheers,
> > > > > > > > > > > > >
> > > > > > > > > > > > > Chris
> > > > > > > > > > > > >
> > > > > > > > > > > > > On Mon, Feb 13, 2023 at 10:54 AM Yash Mayya <
> > > > > > > > yash.mayya@gmail.com>
> > > > > > > > > > > > wrote:
> > > > > > > > > > > > >
> > > > > > > > > > > > > > Hi Chris,
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > > especially if connectors are intentionally
> > designed
> > > > > > around
> > > > > > > > > > > > > > > original topic partitions instead of
> transformed
> > > > ones.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Ha, that's a good point and reminds me of Hyrum's
> > Law
> > > > [1]
> > > > > > :)
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > > I think we have to provide connector developers
> > > with
> > > > > some
> > > > > > > > > > > > > > > way to differentiate between the two, but maybe
> > > > > there's a
> > > > > > > way
> > > > > > > > > > > > > > >  to do this that I haven't thought of yet
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > I can't think of a better way to do this either;
> > > would
> > > > > > > invoking
> > > > > > > > > the
> > > > > > > > > > > > > > existing `SinkTask::open` and `SinkTask::close`
> > > methods
> > > > > > with
> > > > > > > > > > > > > post-transform
> > > > > > > > > > > > > > topic partitions instead of pre-transform topic
> > > > > partitions
> > > > > > > not
> > > > > > > > be
> > > > > > > > > > > > > > acceptable even in a minor / major AK release? I
> > feel
> > > > > like
> > > > > > > the
> > > > > > > > > > > proposed
> > > > > > > > > > > > > > approach of adding overloaded `SinkTask::open` /
> > > > > > > > > `SinkTask::close`
> > > > > > > > > > > > > methods
> > > > > > > > > > > > > > to differentiate between pre-transform and
> > > > post-transform
> > > > > > > topic
> > > > > > > > > > > > > partitions
> > > > > > > > > > > > > > has similar pitfalls to the idea of the
> overloaded
> > > > > > > > > `SinkTask::put`
> > > > > > > > > > > > method
> > > > > > > > > > > > > > we discarded earlier.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Either way, I'm glad that the general idea of a
> > > cache
> > > > > and
> > > > > > > > > > > > > > > eviction policy for SinkTask::close seem
> > > reasonable;
> > > > if
> > > > > > > > > > > > > > > we decide to go this route, it might make sense
> > for
> > > > the
> > > > > > KIP
> > > > > > > > > > > > > > > to include an outline of one or more high-level
> > > > > > strategies
> > > > > > > > > > > > > > > we might take, but without promising any
> > particular
> > > > > > > behavior
> > > > > > > > > > > > > > > beyond occasionally calling SinkTask::close for
> > > > > > > > post-transform
> > > > > > > > > > > > > > > topic partitions. I'm hoping that this logic
> can
> > > stay
> > > > > > > > internal,
> > > > > > > > > > > > > > > and by notpainting ourselves into a corner with
> > the
> > > > > KIP,
> > > > > > we
> > > > > > > > > > > > > > > give ourselves leeway to tweak it in the future
> > if
> > > > > > > necessary
> > > > > > > > > > > > > > > without filing another KIP or introducing a
> > > pluggable
> > > > > > > > > interface.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Thanks, that's a good idea. Given the flexibility
> > of
> > > > > SMTs,
> > > > > > > the
> > > > > > > > > > > > framework
> > > > > > > > > > > > > > can't really make any assumptions around topic
> > > > partitions
> > > > > > > post
> > > > > > > > > > > > > > transformation nor does it have any way to
> > > definitively
> > > > > get
> > > > > > > any
> > > > > > > > > > such
> > > > > > > > > > > > > > information from transformations which is why the
> > > idea
> > > > > of a
> > > > > > > > cache
> > > > > > > > > > > with
> > > > > > > > > > > > an
> > > > > > > > > > > > > > eviction policy makes perfect sense!
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > [1] - https://www.hyrumslaw.com/
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > Yash
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > On Thu, Feb 9, 2023 at 9:38 PM Chris Egerton
> > > > > > > > > > <chrise@aiven.io.invalid
> > > > > > > > > > > >
> > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Hi Yash,
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > So it looks like with the current state of
> > > affairs,
> > > > > > sink
> > > > > > > > > tasks
> > > > > > > > > > > that
> > > > > > > > > > > > > > only
> > > > > > > > > > > > > > > instantiate writers in the SinkTask::open
> method
> > > (and
> > > > > > don't
> > > > > > > > do
> > > > > > > > > > the
> > > > > > > > > > > > lazy
> > > > > > > > > > > > > > > instantiation in SinkTask::put that you
> > mentioned)
> > > > > might
> > > > > > > fail
> > > > > > > > > > when
> > > > > > > > > > > > used
> > > > > > > > > > > > > > > with topic/partition mutating SMTs even if they
> > > don't
> > > > > do
> > > > > > > any
> > > > > > > > > > > > > asynchronous
> > > > > > > > > > > > > > > processing?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Yep, exactly 👍
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > What do you think about retaining just the
> > > existing
> > > > > > > methods
> > > > > > > > > > > > > > > but changing when they're called in the Connect
> > > > > runtime?
> > > > > > > For
> > > > > > > > > > > > instance,
> > > > > > > > > > > > > > > instead of calling SinkTask::open after
> partition
> > > > > > > assignment
> > > > > > > > > > post a
> > > > > > > > > > > > > > > consumer group rebalance, we could cache the
> > > > currently
> > > > > > > "seen"
> > > > > > > > > > topic
> > > > > > > > > > > > > > > partitions (post transformation) and before
> each
> > > call
> > > > > to
> > > > > > > > > > > > SinkTask::put
> > > > > > > > > > > > > > > check whether there's any new "unseen" topic
> > > > > partitions,
> > > > > > > and
> > > > > > > > if
> > > > > > > > > > so
> > > > > > > > > > > > call
> > > > > > > > > > > > > > > SinkTask::open (and also update the cache of
> > > course).
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > IMO the issue here is that it's a drastic
> change
> > in
> > > > > > > behavior
> > > > > > > > to
> > > > > > > > > > > start
> > > > > > > > > > > > > > > invoking SinkTask::open and SinkTask::close
> with
> > > > > > > > post-transform
> > > > > > > > > > > topic
> > > > > > > > > > > > > > > partitions instead of pre-transform, especially
> > if
> > > > > > > connectors
> > > > > > > > > are
> > > > > > > > > > > > > > > intentionally designed around original topic
> > > > partitions
> > > > > > > > instead
> > > > > > > > > > of
> > > > > > > > > > > > > > > transformed ones. I think we have to provide
> > > > connector
> > > > > > > > > developers
> > > > > > > > > > > > with
> > > > > > > > > > > > > > some
> > > > > > > > > > > > > > > way to differentiate between the two, but maybe
> > > > > there's a
> > > > > > > way
> > > > > > > > > to
> > > > > > > > > > do
> > > > > > > > > > > > > this
> > > > > > > > > > > > > > > that I haven't thought of yet. Interested to
> hear
> > > > your
> > > > > > > > > thoughts.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Either way, I'm glad that the general idea of a
> > > cache
> > > > > and
> > > > > > > > > > eviction
> > > > > > > > > > > > > policy
> > > > > > > > > > > > > > > for SinkTask::close seem reasonable; if we
> decide
> > > to
> > > > go
> > > > > > > this
> > > > > > > > > > route,
> > > > > > > > > > > > it
> > > > > > > > > > > > > > > might make sense for the KIP to include an
> > outline
> > > of
> > > > > one
> > > > > > > or
> > > > > > > > > more
> > > > > > > > > > > > > > > high-level strategies we might take, but
> without
> > > > > > promising
> > > > > > > > any
> > > > > > > > > > > > > particular
> > > > > > > > > > > > > > > behavior beyond occasionally calling
> > > SinkTask::close
> > > > > for
> > > > > > > > > > > > post-transform
> > > > > > > > > > > > > > > topic partitions. I'm hoping that this logic
> can
> > > stay
> > > > > > > > internal,
> > > > > > > > > > and
> > > > > > > > > > > > by
> > > > > > > > > > > > > > not
> > > > > > > > > > > > > > > painting ourselves into a corner with the KIP,
> we
> > > > give
> > > > > > > > > ourselves
> > > > > > > > > > > > leeway
> > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > tweak it in the future if necessary without
> > filing
> > > > > > another
> > > > > > > > KIP
> > > > > > > > > or
> > > > > > > > > > > > > > > introducing a pluggable interface.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Cheers,
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Chris
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > On Thu, Feb 9, 2023 at 7:39 AM Yash Mayya <
> > > > > > > > > yash.mayya@gmail.com>
> > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Hi Chris,
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Thanks for the feedback.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 1) That's a fair point; while I did scan
> > > everything
> > > > > > > > publicly
> > > > > > > > > > > > > available
> > > > > > > > > > > > > > on
> > > > > > > > > > > > > > > > GitHub, you're right in that it won't cover
> all
> > > > > > possible
> > > > > > > > SMTs
> > > > > > > > > > > that
> > > > > > > > > > > > > are
> > > > > > > > > > > > > > > out
> > > > > > > > > > > > > > > > there. Thanks for the example use-case as
> well,
> > > > I've
> > > > > > > > updated
> > > > > > > > > > the
> > > > > > > > > > > > KIP
> > > > > > > > > > > > > to
> > > > > > > > > > > > > > > add
> > > > > > > > > > > > > > > > the two new proposed methods.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 2) So it looks like with the current state of
> > > > > affairs,
> > > > > > > sink
> > > > > > > > > > tasks
> > > > > > > > > > > > > that
> > > > > > > > > > > > > > > only
> > > > > > > > > > > > > > > > instantiate writers in the SinkTask::open
> > method
> > > > (and
> > > > > > > don't
> > > > > > > > > do
> > > > > > > > > > > the
> > > > > > > > > > > > > lazy
> > > > > > > > > > > > > > > > instantiation in SinkTask::put that you
> > > mentioned)
> > > > > > might
> > > > > > > > fail
> > > > > > > > > > > when
> > > > > > > > > > > > > used
> > > > > > > > > > > > > > > > with topic/partition mutating SMTs even if
> they
> > > > don't
> > > > > > do
> > > > > > > > any
> > > > > > > > > > > > > > asynchronous
> > > > > > > > > > > > > > > > processing? Since they could encounter
> records
> > in
> > > > > > > > > SinkTask::put
> > > > > > > > > > > > with
> > > > > > > > > > > > > > > > topics/partitions that they might not have
> > > created
> > > > > > > writers
> > > > > > > > > for.
> > > > > > > > > > > > > Thanks
> > > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > pointing this out, it's definitely another
> > > > > > > incompatibility
> > > > > > > > > that
> > > > > > > > > > > > needs
> > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > be
> > > > > > > > > > > > > > > > called out and fixed. The overloaded method
> > > > approach
> > > > > is
> > > > > > > > > > > > interesting,
> > > > > > > > > > > > > > but
> > > > > > > > > > > > > > > > comes with the caveat of yet more new methods
> > > that
> > > > > will
> > > > > > > > need
> > > > > > > > > to
> > > > > > > > > > > be
> > > > > > > > > > > > > > > > implemented by existing connectors if they
> want
> > > to
> > > > > make
> > > > > > > use
> > > > > > > > > of
> > > > > > > > > > > this
> > > > > > > > > > > > > new
> > > > > > > > > > > > > > > > functionality. What do you think about
> > retaining
> > > > just
> > > > > > the
> > > > > > > > > > > existing
> > > > > > > > > > > > > > > methods
> > > > > > > > > > > > > > > > but changing when they're called in the
> Connect
> > > > > > runtime?
> > > > > > > > For
> > > > > > > > > > > > > instance,
> > > > > > > > > > > > > > > > instead of calling SinkTask::open after
> > partition
> > > > > > > > assignment
> > > > > > > > > > > post a
> > > > > > > > > > > > > > > > consumer group rebalance, we could cache the
> > > > > currently
> > > > > > > > "seen"
> > > > > > > > > > > topic
> > > > > > > > > > > > > > > > partitions (post transformation) and before
> > each
> > > > call
> > > > > > to
> > > > > > > > > > > > > SinkTask::put
> > > > > > > > > > > > > > > > check whether there's any new "unseen" topic
> > > > > > partitions,
> > > > > > > > and
> > > > > > > > > if
> > > > > > > > > > > so
> > > > > > > > > > > > > call
> > > > > > > > > > > > > > > > SinkTask::open (and also update the cache of
> > > > > course). I
> > > > > > > > don't
> > > > > > > > > > > think
> > > > > > > > > > > > > > this
> > > > > > > > > > > > > > > > would break the existing contract with sink
> > tasks
> > > > > where
> > > > > > > > > > > > > SinkTask::open
> > > > > > > > > > > > > > is
> > > > > > > > > > > > > > > > expected to be called for a topic partition
> > > before
> > > > > any
> > > > > > > > > records
> > > > > > > > > > > from
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > topic partition are sent via SinkTask::put?
> The
> > > > > > > > > SinkTask::close
> > > > > > > > > > > > case
> > > > > > > > > > > > > > is a
> > > > > > > > > > > > > > > > lot trickier however, and would require some
> > sort
> > > > of
> > > > > > > cache
> > > > > > > > > > > eviction
> > > > > > > > > > > > > > > policy
> > > > > > > > > > > > > > > > that would be deemed appropriate as you
> pointed
> > > out
> > > > > > too.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > Yash
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > On Mon, Feb 6, 2023 at 11:27 PM Chris Egerton
> > > > > > > > > > > > > <chrise@aiven.io.invalid
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Hi Yash,
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > I've had some time to think on this KIP
> and I
> > > > think
> > > > > > I'm
> > > > > > > > in
> > > > > > > > > > > > > agreement
> > > > > > > > > > > > > > > > about
> > > > > > > > > > > > > > > > > not blocking it on an official
> compatibility
> > > > > library
> > > > > > or
> > > > > > > > > > adding
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > "ack"
> > > > > > > > > > > > > > > > > API for sink records.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > I only have two more thoughts:
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 1. Because it is possible to manipulate
> sink
> > > > record
> > > > > > > > > > partitions
> > > > > > > > > > > > and
> > > > > > > > > > > > > > > > offsets
> > > > > > > > > > > > > > > > > with the current API we provide for
> > > > > transformations,
> > > > > > I
> > > > > > > > > still
> > > > > > > > > > > > > believe
> > > > > > > > > > > > > > > > > methods should be added to the SinkRecord
> > class
> > > > to
> > > > > > > expose
> > > > > > > > > the
> > > > > > > > > > > > > > original
> > > > > > > > > > > > > > > > > partition and offset, not just the original
> > > > topic.
> > > > > > The
> > > > > > > > > > > additional
> > > > > > > > > > > > > > > > cognitive
> > > > > > > > > > > > > > > > > burden from these two methods is going to
> be
> > > > > minimal
> > > > > > > > > anyways;
> > > > > > > > > > > > once
> > > > > > > > > > > > > > > users
> > > > > > > > > > > > > > > > > understand the difference between the
> > > transformed
> > > > > > topic
> > > > > > > > > name
> > > > > > > > > > > and
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > original one, it's going to be trivial for
> > them
> > > > to
> > > > > > > > > understand
> > > > > > > > > > > how
> > > > > > > > > > > > > > that
> > > > > > > > > > > > > > > > same
> > > > > > > > > > > > > > > > > difference applies for partitions and
> > offsets.
> > > > It's
> > > > > > not
> > > > > > > > > > enough
> > > > > > > > > > > to
> > > > > > > > > > > > > > scan
> > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > set of SMTs provided out of the box with
> > > Connect,
> > > > > > ones
> > > > > > > > > > > developed
> > > > > > > > > > > > by
> > > > > > > > > > > > > > > > > Confluent, or even everything available on
> > > > GitHub,
> > > > > > > since
> > > > > > > > > > there
> > > > > > > > > > > > may
> > > > > > > > > > > > > be
> > > > > > > > > > > > > > > > > closed-source projects out there that rely
> on
> > > > this
> > > > > > > > ability.
> > > > > > > > > > One
> > > > > > > > > > > > > > > potential
> > > > > > > > > > > > > > > > > use case could be re-routing partitions
> > between
> > > > > Kafka
> > > > > > > and
> > > > > > > > > > some
> > > > > > > > > > > > > other
> > > > > > > > > > > > > > > > > sharded system.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > 2. We still have to address the
> > SinkTask::open
> > > > [1]
> > > > > > and
> > > > > > > > > > > > > > SinkTask::close
> > > > > > > > > > > > > > > > [2]
> > > > > > > > > > > > > > > > > methods. If a connector writes to the
> > external
> > > > > system
> > > > > > > > using
> > > > > > > > > > the
> > > > > > > > > > > > > > > > transformed
> > > > > > > > > > > > > > > > > topic partitions it reads from Kafka, then
> > it's
> > > > > > > possible
> > > > > > > > > for
> > > > > > > > > > > the
> > > > > > > > > > > > > > > > connector
> > > > > > > > > > > > > > > > > to lazily instantiate writers for topic
> > > > partitions
> > > > > as
> > > > > > > it
> > > > > > > > > > > > encounters
> > > > > > > > > > > > > > > them
> > > > > > > > > > > > > > > > > from records provided in SinkTask::put.
> > > However,
> > > > > > > > connectors
> > > > > > > > > > > also
> > > > > > > > > > > > > > need a
> > > > > > > > > > > > > > > > way
> > > > > > > > > > > > > > > > > to de-allocate those writers (and the
> > resources
> > > > > used
> > > > > > by
> > > > > > > > > them)
> > > > > > > > > > > > over
> > > > > > > > > > > > > > > time,
> > > > > > > > > > > > > > > > > which they can't do as easily. One possible
> > > > > approach
> > > > > > > here
> > > > > > > > > is
> > > > > > > > > > to
> > > > > > > > > > > > > > > overload
> > > > > > > > > > > > > > > > > SinkTask::open and SinkTask::close with
> > > variants
> > > > > that
> > > > > > > > > > > distinguish
> > > > > > > > > > > > > > > between
> > > > > > > > > > > > > > > > > transformed and original topic partitions,
> > and
> > > > > > default
> > > > > > > to
> > > > > > > > > > > > invoking
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > existing methods with just the original
> topic
> > > > > > > partitions.
> > > > > > > > > We
> > > > > > > > > > > > would
> > > > > > > > > > > > > > then
> > > > > > > > > > > > > > > > > have several options for how the Connect
> > > runtime
> > > > > can
> > > > > > > > invoke
> > > > > > > > > > > these
> > > > > > > > > > > > > > > > methods,
> > > > > > > > > > > > > > > > > but in general, an approach that guarantees
> > > that
> > > > > > tasks
> > > > > > > > are
> > > > > > > > > > > > notified
> > > > > > > > > > > > > > of
> > > > > > > > > > > > > > > > > transformed topic partitions in
> > SinkTask::open
> > > > > before
> > > > > > > any
> > > > > > > > > > > records
> > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > that
> > > > > > > > > > > > > > > > > partition are given to it in SinkTask::put,
> > and
> > > > > > makes a
> > > > > > > > > > > > best-effort
> > > > > > > > > > > > > > > > attempt
> > > > > > > > > > > > > > > > > to close transformed topic partitions that
> > > appear
> > > > > to
> > > > > > no
> > > > > > > > > > longer
> > > > > > > > > > > be
> > > > > > > > > > > > > in
> > > > > > > > > > > > > > > use
> > > > > > > > > > > > > > > > > based on some eviction policy, would
> probably
> > > be
> > > > > > > > > sufficient.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > [1] -
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://kafka.apache.org/33/javadoc/org/apache/kafka/connect/sink/SinkTask.html#open(java.util.Collection)
> > > > > > > > > > > > > > > > > [2] -
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://kafka.apache.org/33/javadoc/org/apache/kafka/connect/sink/SinkTask.html#close(java.util.Collection)
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Cheers,
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Chris
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > On Sat, Nov 5, 2022 at 5:46 AM Yash Mayya <
> > > > > > > > > > > yash.mayya@gmail.com>
> > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > Hi Chris,
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > Thanks a lot for your inputs!
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > would provide a simple, clean interface
> > for
> > > > > > > > developers
> > > > > > > > > to
> > > > > > > > > > > > > > determine
> > > > > > > > > > > > > > > > > > > which features are supported by the
> > version
> > > > of
> > > > > > the
> > > > > > > > > > Connect
> > > > > > > > > > > > > > runtime
> > > > > > > > > > > > > > > > > > > that their plugin has been deployed
> onto
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > I do like the idea of having such a
> public
> > > > > > > > compatibility
> > > > > > > > > > > > library
> > > > > > > > > > > > > -
> > > > > > > > > > > > > > I
> > > > > > > > > > > > > > > > > think
> > > > > > > > > > > > > > > > > > it would remove a lot of restrictions
> from
> > > > > > framework
> > > > > > > > > > > > development
> > > > > > > > > > > > > if
> > > > > > > > > > > > > > > it
> > > > > > > > > > > > > > > > > were
> > > > > > > > > > > > > > > > > > to be widely adopted.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > we might consider adding an API to
> "ack"
> > > sink
> > > > > > > records
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > I agree that this does seem like a more
> > > > intuitive
> > > > > > and
> > > > > > > > > clean
> > > > > > > > > > > > API,
> > > > > > > > > > > > > > but
> > > > > > > > > > > > > > > > I'm
> > > > > > > > > > > > > > > > > > concerned about the backward
> compatibility
> > > > > headache
> > > > > > > > we'd
> > > > > > > > > be
> > > > > > > > > > > > > > imposing
> > > > > > > > > > > > > > > on
> > > > > > > > > > > > > > > > > all
> > > > > > > > > > > > > > > > > > existing sink connectors. Connector
> > > developers
> > > > > will
> > > > > > > > have
> > > > > > > > > to
> > > > > > > > > > > > > > maintain
> > > > > > > > > > > > > > > > two
> > > > > > > > > > > > > > > > > > separate ways of doing offset management
> if
> > > > they
> > > > > > want
> > > > > > > > to
> > > > > > > > > > use
> > > > > > > > > > > > the
> > > > > > > > > > > > > > new
> > > > > > > > > > > > > > > > API
> > > > > > > > > > > > > > > > > > but continue supporting older versions of
> > > Kafka
> > > > > > > > Connect.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > For now, I've reverted the KIP to the
> > > previous
> > > > > > > > iteration
> > > > > > > > > > > which
> > > > > > > > > > > > > > > proposed
> > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > addition of a new `SinkRecord` method to
> > > obtain
> > > > > the
> > > > > > > > > > original
> > > > > > > > > > > > > Kafka
> > > > > > > > > > > > > > > > topic
> > > > > > > > > > > > > > > > > > pre-transformation. One thing to note is
> > that
> > > > > I've
> > > > > > > > > removed
> > > > > > > > > > > the
> > > > > > > > > > > > > > method
> > > > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > > > obtaining the original Kafka partition
> > after
> > > a
> > > > > > > cursory
> > > > > > > > > > search
> > > > > > > > > > > > > > showed
> > > > > > > > > > > > > > > > that
> > > > > > > > > > > > > > > > > > use cases for partition modifying SMTs
> are
> > > > > > primarily
> > > > > > > on
> > > > > > > > > the
> > > > > > > > > > > > > source
> > > > > > > > > > > > > > > > > > connector side.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > > > Yash
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > On Tue, Nov 1, 2022 at 9:22 PM Chris
> > Egerton
> > > > > > > > > > > > > > <chrise@aiven.io.invalid
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Hi all,
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > I have more comments I'd like to make
> on
> > > this
> > > > > KIP
> > > > > > > > when
> > > > > > > > > I
> > > > > > > > > > > have
> > > > > > > > > > > > > > time
> > > > > > > > > > > > > > > > > (sorry
> > > > > > > > > > > > > > > > > > > for the delay, Yash, and thanks for
> your
> > > > > > > patience!),
> > > > > > > > > but
> > > > > > > > > > I
> > > > > > > > > > > > did
> > > > > > > > > > > > > > want
> > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > > chime in and say that I'm also not sure
> > > about
> > > > > > > > > overloading
> > > > > > > > > > > > > > > > > SinkTask::put.
> > > > > > > > > > > > > > > > > > I
> > > > > > > > > > > > > > > > > > > share the concerns about creating an
> > > > intuitive,
> > > > > > > > simple
> > > > > > > > > > API
> > > > > > > > > > > > that
> > > > > > > > > > > > > > > Yash
> > > > > > > > > > > > > > > > > has
> > > > > > > > > > > > > > > > > > > raised. In addition, this approach
> > doesn't
> > > > seem
> > > > > > > very
> > > > > > > > > > > > > > > > sustainable--what
> > > > > > > > > > > > > > > > > do
> > > > > > > > > > > > > > > > > > > we do if we encounter another case in
> the
> > > > > future
> > > > > > > that
> > > > > > > > > > would
> > > > > > > > > > > > > > > warrant a
> > > > > > > > > > > > > > > > > > > similar solution? We probably don't
> want
> > to
> > > > > > create
> > > > > > > > > three,
> > > > > > > > > > > > four,
> > > > > > > > > > > > > > > etc.
> > > > > > > > > > > > > > > > > > > overloaded variants of the method, each
> > of
> > > > > which
> > > > > > > > would
> > > > > > > > > > have
> > > > > > > > > > > > to
> > > > > > > > > > > > > be
> > > > > > > > > > > > > > > > > > > implemented by connector developers who
> > > want
> > > > to
> > > > > > > both
> > > > > > > > > > > leverage
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > latest
> > > > > > > > > > > > > > > > > > > and greatest connector APIs and
> maintain
> > > > > > > > compatibility
> > > > > > > > > > with
> > > > > > > > > > > > > > connect
> > > > > > > > > > > > > > > > > > > Clusters running older versions.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > I haven't been able to flesh this out
> > into
> > > a
> > > > > > design
> > > > > > > > > worth
> > > > > > > > > > > > > > > publishing
> > > > > > > > > > > > > > > > in
> > > > > > > > > > > > > > > > > > its
> > > > > > > > > > > > > > > > > > > own KIP yet, but one alternative I've
> > > pitched
> > > > > to
> > > > > > a
> > > > > > > > few
> > > > > > > > > > > people
> > > > > > > > > > > > > > with
> > > > > > > > > > > > > > > > > > > generally positive interest has been to
> > > > develop
> > > > > > an
> > > > > > > > > > official
> > > > > > > > > > > > > > > > > compatibility
> > > > > > > > > > > > > > > > > > > library for Connect developers. This
> > > library
> > > > > > would
> > > > > > > be
> > > > > > > > > > > > released
> > > > > > > > > > > > > as
> > > > > > > > > > > > > > > its
> > > > > > > > > > > > > > > > > own
> > > > > > > > > > > > > > > > > > > Maven artifact (separate from
> > connect-api,
> > > > > > > > > > connect-runtime,
> > > > > > > > > > > > > etc.)
> > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > would
> > > > > > > > > > > > > > > > > > > provide a simple, clean interface for
> > > > > developers
> > > > > > to
> > > > > > > > > > > determine
> > > > > > > > > > > > > > which
> > > > > > > > > > > > > > > > > > > features are supported by the version
> of
> > > the
> > > > > > > Connect
> > > > > > > > > > > runtime
> > > > > > > > > > > > > that
> > > > > > > > > > > > > > > > their
> > > > > > > > > > > > > > > > > > > plugin has been deployed onto. Under
> the
> > > > hood,
> > > > > > this
> > > > > > > > > > library
> > > > > > > > > > > > > might
> > > > > > > > > > > > > > > use
> > > > > > > > > > > > > > > > > > > reflection to determine whether
> classes,
> > > > > methods,
> > > > > > > > etc.
> > > > > > > > > > are
> > > > > > > > > > > > > > > available,
> > > > > > > > > > > > > > > > > but
> > > > > > > > > > > > > > > > > > > the developer wouldn't have to do
> > anything
> > > > more
> > > > > > > than
> > > > > > > > > > check
> > > > > > > > > > > > (for
> > > > > > > > > > > > > > > > > example)
> > > > > > > > > > > > > > > > > > >
> > > > > > > `Features.SINK_TASK_ERRANT_RECORD_REPORTER.enabled()`
> > > > > > > > > to
> > > > > > > > > > > know
> > > > > > > > > > > > > at
> > > > > > > > > > > > > > > any
> > > > > > > > > > > > > > > > > > point
> > > > > > > > > > > > > > > > > > > in the lifetime of their connector/task
> > > > whether
> > > > > > > that
> > > > > > > > > > > feature
> > > > > > > > > > > > is
> > > > > > > > > > > > > > > > > provided
> > > > > > > > > > > > > > > > > > by
> > > > > > > > > > > > > > > > > > > the runtime.
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > One other high-level comment: this
> > doesn't
> > > > > > address
> > > > > > > > > every
> > > > > > > > > > > > case,
> > > > > > > > > > > > > > but
> > > > > > > > > > > > > > > we
> > > > > > > > > > > > > > > > > > might
> > > > > > > > > > > > > > > > > > > consider adding an API to "ack" sink
> > > records.
> > > > > > This
> > > > > > > > > could
> > > > > > > > > > > use
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > SubmittedRecords class [1] (with some
> > > slight
> > > > > > > tweaks)
> > > > > > > > > > under
> > > > > > > > > > > > the
> > > > > > > > > > > > > > hood
> > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > > track the latest-acked offset for each
> > > topic
> > > > > > > > partition.
> > > > > > > > > > > This
> > > > > > > > > > > > > way,
> > > > > > > > > > > > > > > > > > connector
> > > > > > > > > > > > > > > > > > > developers won't be responsible for
> > > tracking
> > > > > > > offsets
> > > > > > > > at
> > > > > > > > > > all
> > > > > > > > > > > > in
> > > > > > > > > > > > > > > their
> > > > > > > > > > > > > > > > > sink
> > > > > > > > > > > > > > > > > > > tasks (eliminating issues with the
> > accuracy
> > > > of
> > > > > > > > > > > > > > post-transformation
> > > > > > > > > > > > > > > > > T/P/O
> > > > > > > > > > > > > > > > > > > sink record information), and they'll
> > only
> > > > have
> > > > > > to
> > > > > > > > > notify
> > > > > > > > > > > the
> > > > > > > > > > > > > > > Connect
> > > > > > > > > > > > > > > > > > > framework when a record has been
> > > successfully
> > > > > > > > > dispatched
> > > > > > > > > > to
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > external
> > > > > > > > > > > > > > > > > > > system. This provides a cleaner,
> > friendlier
> > > > > API,
> > > > > > > and
> > > > > > > > > also
> > > > > > > > > > > > > enables
> > > > > > > > > > > > > > > > more
> > > > > > > > > > > > > > > > > > > fine-grained metrics like the ones
> > proposed
> > > > in
> > > > > > > > KIP-767
> > > > > > > > > > [2].
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > [1] -
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://github.com/apache/kafka/blob/9ab140d5419d735baae45aff56ffce7f5622744f/connect/runtime/src/main/java/org/apache/kafka/connect/runtime/SubmittedRecords.java
> > > > > > > > > > > > > > > > > > > [2] -
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-767%3A+Connect+Latency+Metrics
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Cheers,
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Chris
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > On Tue, Nov 1, 2022 at 11:21 AM Yash
> > Mayya
> > > <
> > > > > > > > > > > > > yash.mayya@gmail.com
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > Hi Randall,
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > It's been a while for this one but
> the
> > > > more I
> > > > > > > think
> > > > > > > > > > about
> > > > > > > > > > > > it,
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > more
> > > > > > > > > > > > > > > > > > I
> > > > > > > > > > > > > > > > > > > > feel like the current approach with a
> > new
> > > > > > > > overloaded
> > > > > > > > > > > > > > > > `SinkTask::put`
> > > > > > > > > > > > > > > > > > > method
> > > > > > > > > > > > > > > > > > > > might not be optimal. We're trying to
> > > fix a
> > > > > > > pretty
> > > > > > > > > > corner
> > > > > > > > > > > > > case
> > > > > > > > > > > > > > > bug
> > > > > > > > > > > > > > > > > here
> > > > > > > > > > > > > > > > > > > > (usage of topic mutating SMTs with
> sink
> > > > > > > connectors
> > > > > > > > > that
> > > > > > > > > > > do
> > > > > > > > > > > > > > their
> > > > > > > > > > > > > > > > own
> > > > > > > > > > > > > > > > > > > offset
> > > > > > > > > > > > > > > > > > > > tracking) and I'm not sure that
> > warrants
> > > a
> > > > > > change
> > > > > > > > to
> > > > > > > > > > > such a
> > > > > > > > > > > > > > > central
> > > > > > > > > > > > > > > > > > > > interface method. The new
> > `SinkTask::put`
> > > > > > method
> > > > > > > > just
> > > > > > > > > > > seems
> > > > > > > > > > > > > > > > somewhat
> > > > > > > > > > > > > > > > > > odd
> > > > > > > > > > > > > > > > > > > > and it may not be very understandable
> > > for a
> > > > > new
> > > > > > > > > reader
> > > > > > > > > > -
> > > > > > > > > > > I
> > > > > > > > > > > > > > don't
> > > > > > > > > > > > > > > > > think
> > > > > > > > > > > > > > > > > > > this
> > > > > > > > > > > > > > > > > > > > should be the case for a public
> > interface
> > > > > > method.
> > > > > > > > > > > > > Furthermore,
> > > > > > > > > > > > > > > even
> > > > > > > > > > > > > > > > > > with
> > > > > > > > > > > > > > > > > > > > elaborate documentation in place, I'm
> > not
> > > > > sure
> > > > > > if
> > > > > > > > > it'll
> > > > > > > > > > > be
> > > > > > > > > > > > > very
> > > > > > > > > > > > > > > > > obvious
> > > > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > > > most people what the purpose of
> having
> > > > these
> > > > > > two
> > > > > > > > > `put`
> > > > > > > > > > > > > methods
> > > > > > > > > > > > > > is
> > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > how
> > > > > > > > > > > > > > > > > > > > they should be used by sink task
> > > > > > implementations.
> > > > > > > > > What
> > > > > > > > > > do
> > > > > > > > > > > > you
> > > > > > > > > > > > > > > > think?
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > > > > > Yash
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > On Mon, Oct 10, 2022 at 9:33 PM Yash
> > > Mayya
> > > > <
> > > > > > > > > > > > > > yash.mayya@gmail.com
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > Hi Randall,
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > Thanks a lot for your valuable
> > feedback
> > > > so
> > > > > > far!
> > > > > > > > > I've
> > > > > > > > > > > > > updated
> > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > KIP
> > > > > > > > > > > > > > > > > > > > based
> > > > > > > > > > > > > > > > > > > > > on our discussion above. Could you
> > > please
> > > > > > take
> > > > > > > > > > another
> > > > > > > > > > > > > look?
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > > > > > > Yash
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > > On Tue, Oct 4, 2022 at 12:40 AM
> > Randall
> > > > > > Hauch <
> > > > > > > > > > > > > > > rhauch@gmail.com>
> > > > > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >> On Mon, Oct 3, 2022 at 11:45 AM
> Yash
> > > > > Mayya <
> > > > > > > > > > > > > > > > yash.mayya@gmail.com>
> > > > > > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >> > Hi Randall,
> > > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > > >> > Thanks for elaborating. I think
> > > these
> > > > > are
> > > > > > > all
> > > > > > > > > very
> > > > > > > > > > > > good
> > > > > > > > > > > > > > > points
> > > > > > > > > > > > > > > > > > and I
> > > > > > > > > > > > > > > > > > > > see
> > > > > > > > > > > > > > > > > > > > >> > why the overloaded
> `SinkTask::put`
> > > > > method
> > > > > > > is a
> > > > > > > > > > > cleaner
> > > > > > > > > > > > > > > > solution
> > > > > > > > > > > > > > > > > > > > overall.
> > > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > > >> > > public void
> > > > put(Collection<SinkRecord>
> > > > > > > > > records,
> > > > > > > > > > > > > > > > > Map<SinkRecord,
> > > > > > > > > > > > > > > > > > > > >> > TopicPartition>
> > > > updatedTopicPartitions)
> > > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > > >> > I think this should be
> > > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > > >> > `public void
> > > > put(Collection<SinkRecord>
> > > > > > > > records,
> > > > > > > > > > > > > > > > Map<SinkRecord,
> > > > > > > > > > > > > > > > > > > > >> > TopicPartition>
> > > > > originalTopicPartitions)`
> > > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > > >> > instead because the sink records
> > > > > > themselves
> > > > > > > > have
> > > > > > > > > > the
> > > > > > > > > > > > > > updated
> > > > > > > > > > > > > > > > > topic
> > > > > > > > > > > > > > > > > > > > >> > partitions (i.e. after all
> > > > > transformations
> > > > > > > > have
> > > > > > > > > > been
> > > > > > > > > > > > > > > applied)
> > > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > > >> KIP
> > > > > > > > > > > > > > > > > > > > >> > is proposing a way for the tasks
> > to
> > > be
> > > > > > able
> > > > > > > to
> > > > > > > > > > > access
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > original
> > > > > > > > > > > > > > > > > > > > topic
> > > > > > > > > > > > > > > > > > > > >> > partition (i.e. before
> > > transformations
> > > > > > have
> > > > > > > > been
> > > > > > > > > > > > > applied).
> > > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >> Sounds good.
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > > >> > > Of course, if the developer
> does
> > > not
> > > > > > need
> > > > > > > > > > separate
> > > > > > > > > > > > > > > methods,
> > > > > > > > > > > > > > > > > they
> > > > > > > > > > > > > > > > > > > can
> > > > > > > > > > > > > > > > > > > > >> > easily have the older `put`
> method
> > > > > simply
> > > > > > > > > delegate
> > > > > > > > > > > to
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > newer
> > > > > > > > > > > > > > > > > > > > method.
> > > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > > >> > If the developer does not need
> > > > separate
> > > > > > > > methods
> > > > > > > > > > > (i.e.
> > > > > > > > > > > > > they
> > > > > > > > > > > > > > > > don't
> > > > > > > > > > > > > > > > > > > need
> > > > > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > > > >> > use this new addition), they can
> > > > simply
> > > > > > > > continue
> > > > > > > > > > > > > > > implementing
> > > > > > > > > > > > > > > > > just
> > > > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > > >> > older `put` method right?
> > > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >> Correct. We should update the
> > JavaDoc
> > > of
> > > > > > both
> > > > > > > > > > methods
> > > > > > > > > > > to
> > > > > > > > > > > > > > make
> > > > > > > > > > > > > > > > this
> > > > > > > > > > > > > > > > > > > > clear,
> > > > > > > > > > > > > > > > > > > > >> and in general how the two methods
> > > > should
> > > > > > are
> > > > > > > > used
> > > > > > > > > > and
> > > > > > > > > > > > > > should
> > > > > > > > > > > > > > > be
> > > > > > > > > > > > > > > > > > > > >> implemented. That can be part of
> the
> > > PR,
> > > > > and
> > > > > > > the
> > > > > > > > > KIP
> > > > > > > > > > > > > doesn't
> > > > > > > > > > > > > > > > need
> > > > > > > > > > > > > > > > > > this
> > > > > > > > > > > > > > > > > > > > >> wording.
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > > >> > > Finally, this gives us a
> roadmap
> > > for
> > > > > > > > > > *eventually*
> > > > > > > > > > > > > > > > deprecating
> > > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > > >> older
> > > > > > > > > > > > > > > > > > > > >> > method, once the Connect runtime
> > > > > versions
> > > > > > > > > without
> > > > > > > > > > > this
> > > > > > > > > > > > > > > change
> > > > > > > > > > > > > > > > > are
> > > > > > > > > > > > > > > > > > > old
> > > > > > > > > > > > > > > > > > > > >> > enough.
> > > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > > >> > I'm not sure we'd ever want to
> > > > deprecate
> > > > > > the
> > > > > > > > > older
> > > > > > > > > > > > > method.
> > > > > > > > > > > > > > > > Most
> > > > > > > > > > > > > > > > > > > common
> > > > > > > > > > > > > > > > > > > > >> sink
> > > > > > > > > > > > > > > > > > > > >> > connector implementations do not
> > do
> > > > > their
> > > > > > > own
> > > > > > > > > > offset
> > > > > > > > > > > > > > > tracking
> > > > > > > > > > > > > > > > > with
> > > > > > > > > > > > > > > > > > > > >> > asynchronous processing and will
> > > > > probably
> > > > > > > > never
> > > > > > > > > > > have a
> > > > > > > > > > > > > > need
> > > > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > > >> > additional parameter
> > > `Map<SinkRecord,
> > > > > > > > > > > TopicPartition>
> > > > > > > > > > > > > > > > > > > > >> > originalTopicPartitions` in the
> > > > proposed
> > > > > > new
> > > > > > > > > `put`
> > > > > > > > > > > > > method.
> > > > > > > > > > > > > > > > These
> > > > > > > > > > > > > > > > > > > > >> connectors
> > > > > > > > > > > > > > > > > > > > >> > can continue implementing only
> the
> > > > > > existing
> > > > > > > > > > > > > > `SinkTask::put`
> > > > > > > > > > > > > > > > > method
> > > > > > > > > > > > > > > > > > > > which
> > > > > > > > > > > > > > > > > > > > >> > will be called by the default
> > > > > > implementation
> > > > > > > > of
> > > > > > > > > > the
> > > > > > > > > > > > > newer
> > > > > > > > > > > > > > > > > > overloaded
> > > > > > > > > > > > > > > > > > > > >> `put`
> > > > > > > > > > > > > > > > > > > > >> > method.
> > > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >> +1
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > > >> > > the pre-commit methods use the
> > > same
> > > > > > > > > > > > > `Map<TopicPartition,
> > > > > > > > > > > > > > > > > > > > >> > OffsetAndMetadata>
> currentOffsets`
> > > > data
> > > > > > > > > structure
> > > > > > > > > > > I'm
> > > > > > > > > > > > > > > > suggesting
> > > > > > > > > > > > > > > > > > be
> > > > > > > > > > > > > > > > > > > > >> used.
> > > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > > >> > The data structure you're
> > suggesting
> > > > be
> > > > > > used
> > > > > > > > is
> > > > > > > > > a
> > > > > > > > > > > > > > > > > `Map<SinkRecord,
> > > > > > > > > > > > > > > > > > > > >> > TopicPartition>` which will map
> > > > > > `SinkRecord`
> > > > > > > > > > objects
> > > > > > > > > > > > to
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > original
> > > > > > > > > > > > > > > > > > > > >> topic
> > > > > > > > > > > > > > > > > > > > >> > partition of the corresponding
> > > > > > > > `ConsumerRecord`
> > > > > > > > > > > right?
> > > > > > > > > > > > > To
> > > > > > > > > > > > > > > > > clarify,
> > > > > > > > > > > > > > > > > > > > this
> > > > > > > > > > > > > > > > > > > > >> is
> > > > > > > > > > > > > > > > > > > > >> > a new data structure that will
> > need
> > > to
> > > > > be
> > > > > > > > > managed
> > > > > > > > > > in
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > > >> `WorkerSinkTask`.
> > > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >> Ah, you're right. Thanks for the
> > > > > correction.
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >> Best regards,
> > > > > > > > > > > > > > > > > > > > >> Randall
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >> > Thanks,
> > > > > > > > > > > > > > > > > > > > >> > Yash
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >> > On Mon, Oct 3, 2022 at 1:20 AM
> > > Randall
> > > > > > > Hauch <
> > > > > > > > > > > > > > > > rhauch@gmail.com>
> > > > > > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > > >> > > Hi, Yash.
> > > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > > >> > > I'm not sure I quite
> understand
> > > why
> > > > it
> > > > > > > would
> > > > > > > > > be
> > > > > > > > > > > > > "easier"
> > > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > > > > > connector
> > > > > > > > > > > > > > > > > > > > >> > > > developers to account for
> > > > > implementing
> > > > > > > two
> > > > > > > > > > > > different
> > > > > > > > > > > > > > > > > > overloaded
> > > > > > > > > > > > > > > > > > > > >> `put`
> > > > > > > > > > > > > > > > > > > > >> > > > methods (assuming that they
> > want
> > > > to
> > > > > > use
> > > > > > > > this
> > > > > > > > > > new
> > > > > > > > > > > > > > > feature)
> > > > > > > > > > > > > > > > > > versus
> > > > > > > > > > > > > > > > > > > > >> using
> > > > > > > > > > > > > > > > > > > > >> > a
> > > > > > > > > > > > > > > > > > > > >> > > > try-catch block around
> > > > `SinkRecord`
> > > > > > > access
> > > > > > > > > > > > methods?
> > > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > > >> > > Using a try-catch to try
> around
> > an
> > > > API
> > > > > > > > method
> > > > > > > > > > that
> > > > > > > > > > > > > > *might*
> > > > > > > > > > > > > > > > be
> > > > > > > > > > > > > > > > > > > there
> > > > > > > > > > > > > > > > > > > > >> is a
> > > > > > > > > > > > > > > > > > > > >> > > very unusual thing for most
> > > > > developers.
> > > > > > > > > > > > Unfortunately,
> > > > > > > > > > > > > > > we've
> > > > > > > > > > > > > > > > > had
> > > > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > > > >> > resort
> > > > > > > > > > > > > > > > > > > > >> > > to this atypical approach with
> > > > Connect
> > > > > > in
> > > > > > > > > places
> > > > > > > > > > > > when
> > > > > > > > > > > > > > > there
> > > > > > > > > > > > > > > > > was
> > > > > > > > > > > > > > > > > > no
> > > > > > > > > > > > > > > > > > > > >> good
> > > > > > > > > > > > > > > > > > > > >> > > alternative. We seem to
> relying
> > > upon
> > > > > > > pattern
> > > > > > > > > > > because
> > > > > > > > > > > > > > it's
> > > > > > > > > > > > > > > > > easier
> > > > > > > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > > > > > >> us,
> > > > > > > > > > > > > > > > > > > > >> > > not because it offers a better
> > > > > > experience
> > > > > > > > for
> > > > > > > > > > > > > Connector
> > > > > > > > > > > > > > > > > > > developers.
> > > > > > > > > > > > > > > > > > > > >> IMO,
> > > > > > > > > > > > > > > > > > > > >> > if
> > > > > > > > > > > > > > > > > > > > >> > > there's a practical
> alternative
> > > that
> > > > > > uses
> > > > > > > > > normal
> > > > > > > > > > > > > > > development
> > > > > > > > > > > > > > > > > > > > practices
> > > > > > > > > > > > > > > > > > > > >> > and
> > > > > > > > > > > > > > > > > > > > >> > > techniques, then we should use
> > > that
> > > > > > > > > alternative.
> > > > > > > > > > > > IIUC,
> > > > > > > > > > > > > > > there
> > > > > > > > > > > > > > > > > is
> > > > > > > > > > > > > > > > > > at
> > > > > > > > > > > > > > > > > > > > >> least
> > > > > > > > > > > > > > > > > > > > >> > > one practical alternative for
> > this
> > > > KIP
> > > > > > > that
> > > > > > > > > > would
> > > > > > > > > > > > not
> > > > > > > > > > > > > > > > require
> > > > > > > > > > > > > > > > > > > > >> developers
> > > > > > > > > > > > > > > > > > > > >> > to
> > > > > > > > > > > > > > > > > > > > >> > > use the unusual try-catch to
> > > handle
> > > > > the
> > > > > > > case
> > > > > > > > > > where
> > > > > > > > > > > > > > methods
> > > > > > > > > > > > > > > > are
> > > > > > > > > > > > > > > > > > not
> > > > > > > > > > > > > > > > > > > > >> found.
> > > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > > >> > > I also think having two `put`
> > > > methods
> > > > > is
> > > > > > > > > easier
> > > > > > > > > > > when
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > Connector
> > > > > > > > > > > > > > > > > > > > >> has to
> > > > > > > > > > > > > > > > > > > > >> > > do different things for
> > different
> > > > > > Connect
> > > > > > > > > > > runtimes,
> > > > > > > > > > > > > too.
> > > > > > > > > > > > > > > One
> > > > > > > > > > > > > > > > > of
> > > > > > > > > > > > > > > > > > > > those
> > > > > > > > > > > > > > > > > > > > >> > > methods is called by newer
> > Connect
> > > > > > > runtimes
> > > > > > > > > with
> > > > > > > > > > > the
> > > > > > > > > > > > > new
> > > > > > > > > > > > > > > > > > behavior,
> > > > > > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > > >> > the
> > > > > > > > > > > > > > > > > > > > >> > > other method is called by an
> > older
> > > > > > Connect
> > > > > > > > > > > runtime.
> > > > > > > > > > > > Of
> > > > > > > > > > > > > > > > course,
> > > > > > > > > > > > > > > > > > if
> > > > > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > > >> > > developer does not need
> separate
> > > > > > methods,
> > > > > > > > they
> > > > > > > > > > can
> > > > > > > > > > > > > > easily
> > > > > > > > > > > > > > > > have
> > > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > > >> older
> > > > > > > > > > > > > > > > > > > > >> > > `put` method simply delegate
> to
> > > the
> > > > > > newer
> > > > > > > > > > method.
> > > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > > >> > > Finally, this gives us a
> roadmap
> > > for
> > > > > > > > > > *eventually*
> > > > > > > > > > > > > > > > deprecating
> > > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > > >> older
> > > > > > > > > > > > > > > > > > > > >> > > method, once the Connect
> runtime
> > > > > > versions
> > > > > > > > > > without
> > > > > > > > > > > > this
> > > > > > > > > > > > > > > > change
> > > > > > > > > > > > > > > > > > are
> > > > > > > > > > > > > > > > > > > > old
> > > > > > > > > > > > > > > > > > > > >> > > enough.
> > > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > > >> > > I think the advantage of going
> > > with
> > > > > the
> > > > > > > > > > > > > > > > > > > > >> > > > proposed approach in the KIP
> > is
> > > > that
> > > > > > it
> > > > > > > > > > wouldn't
> > > > > > > > > > > > > > require
> > > > > > > > > > > > > > > > > extra
> > > > > > > > > > > > > > > > > > > > >> > > book-keeping
> > > > > > > > > > > > > > > > > > > > >> > > > (the Map<SinkRecord,
> > > > > > > > > > > > > > > > > > > > >> > > > TopicPartition> in
> > > > `WorkerSinkTask`
> > > > > in
> > > > > > > > your
> > > > > > > > > > > > proposed
> > > > > > > > > > > > > > > > > approach)
> > > > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > > >> > > The connector does have to do
> > some
> > > > of
> > > > > > this
> > > > > > > > > > > > bookkeeping
> > > > > > > > > > > > > > in
> > > > > > > > > > > > > > > > how
> > > > > > > > > > > > > > > > > > they
> > > > > > > > > > > > > > > > > > > > >> track
> > > > > > > > > > > > > > > > > > > > >> > > the topic partition offsets
> used
> > > in
> > > > > the
> > > > > > > > > > > `preCommit`,
> > > > > > > > > > > > > and
> > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > > >> pre-commit
> > > > > > > > > > > > > > > > > > > > >> > > methods use the same
> > > > > > `Map<TopicPartition,
> > > > > > > > > > > > > > > OffsetAndMetadata>
> > > > > > > > > > > > > > > > > > > > >> > > currentOffsets`
> > > > > > > > > > > > > > > > > > > > >> > > data structure I'm suggesting
> be
> > > > used.
> > > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > > >> > > I hope that helps.
> > > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > > >> > > Best regards,
> > > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > > >> > > Randall
> > > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > > >> > > On Mon, Sep 26, 2022 at 9:38
> AM
> > > Yash
> > > > > > > Mayya <
> > > > > > > > > > > > > > > > > > yash.mayya@gmail.com>
> > > > > > > > > > > > > > > > > > > > >> wrote:
> > > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > > >> > > > Hi Randall,
> > > > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > > > >> > > > Thanks for reviewing the
> KIP!
> > > > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > > > >> > > > > That latter logic can get
> > > quite
> > > > > > ugly.
> > > > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > > > >> > > > I'm not sure I quite
> > understand
> > > > why
> > > > > it
> > > > > > > > would
> > > > > > > > > > be
> > > > > > > > > > > > > > "easier"
> > > > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > > > > > >> connector
> > > > > > > > > > > > > > > > > > > > >> > > > developers to account for
> > > > > implementing
> > > > > > > two
> > > > > > > > > > > > different
> > > > > > > > > > > > > > > > > > overloaded
> > > > > > > > > > > > > > > > > > > > >> `put`
> > > > > > > > > > > > > > > > > > > > >> > > > methods (assuming that they
> > want
> > > > to
> > > > > > use
> > > > > > > > this
> > > > > > > > > > new
> > > > > > > > > > > > > > > feature)
> > > > > > > > > > > > > > > > > > versus
> > > > > > > > > > > > > > > > > > > > >> using
> > > > > > > > > > > > > > > > > > > > >> > a
> > > > > > > > > > > > > > > > > > > > >> > > > try-catch block around
> > > > `SinkRecord`
> > > > > > > access
> > > > > > > > > > > > methods?
> > > > > > > > > > > > > In
> > > > > > > > > > > > > > > > both
> > > > > > > > > > > > > > > > > > > > cases, a
> > > > > > > > > > > > > > > > > > > > >> > > > connector developer would
> need
> > > to
> > > > > > write
> > > > > > > > > > > additional
> > > > > > > > > > > > > > code
> > > > > > > > > > > > > > > in
> > > > > > > > > > > > > > > > > > order
> > > > > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > > > >> > > ensure
> > > > > > > > > > > > > > > > > > > > >> > > > that their connector
> continues
> > > > > working
> > > > > > > > with
> > > > > > > > > > > older
> > > > > > > > > > > > > > > Connect
> > > > > > > > > > > > > > > > > > > > runtimes.
> > > > > > > > > > > > > > > > > > > > >> > > > Furthermore, we would
> probably
> > > > need
> > > > > to
> > > > > > > > > > carefully
> > > > > > > > > > > > > > > document
> > > > > > > > > > > > > > > > > how
> > > > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > > >> > > > implementation for the older
> > > `put`
> > > > > > > method
> > > > > > > > > > should
> > > > > > > > > > > > > look
> > > > > > > > > > > > > > > like
> > > > > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > > > > > >> > connectors
> > > > > > > > > > > > > > > > > > > > >> > > > that want to use this new
> > > > feature. I
> > > > > > > think
> > > > > > > > > the
> > > > > > > > > > > > > > advantage
> > > > > > > > > > > > > > > > of
> > > > > > > > > > > > > > > > > > > going
> > > > > > > > > > > > > > > > > > > > >> with
> > > > > > > > > > > > > > > > > > > > >> > > the
> > > > > > > > > > > > > > > > > > > > >> > > > proposed approach in the KIP
> > is
> > > > that
> > > > > > it
> > > > > > > > > > wouldn't
> > > > > > > > > > > > > > require
> > > > > > > > > > > > > > > > > extra
> > > > > > > > > > > > > > > > > > > > >> > > book-keeping
> > > > > > > > > > > > > > > > > > > > >> > > > (the Map<SinkRecord,
> > > > > > > > > > > > > > > > > > > > >> > > > TopicPartition> in
> > > > `WorkerSinkTask`
> > > > > in
> > > > > > > > your
> > > > > > > > > > > > proposed
> > > > > > > > > > > > > > > > > approach)
> > > > > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > > >> also
> > > > > > > > > > > > > > > > > > > > >> > > the
> > > > > > > > > > > > > > > > > > > > >> > > > fact that the try-catch
> based
> > > > logic
> > > > > is
> > > > > > > an
> > > > > > > > > > > already
> > > > > > > > > > > > > > > > > established
> > > > > > > > > > > > > > > > > > > > >> pattern
> > > > > > > > > > > > > > > > > > > > >> > > > through
> > > > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-610%3A+Error+Reporting+in+Sink+Connectors
> > > > > > > > > > > > > > > > > > > > >> > > > and other KIPs which added
> > > methods
> > > > > to
> > > > > > > > > > > source/sink
> > > > > > > > > > > > > > > > > > connector/task
> > > > > > > > > > > > > > > > > > > > >> > > contexts.
> > > > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > > > >> > > > Let me know if you still
> feel
> > > that
> > > > > > > having
> > > > > > > > a
> > > > > > > > > > new
> > > > > > > > > > > > > > > overloaded
> > > > > > > > > > > > > > > > > put
> > > > > > > > > > > > > > > > > > > > >> method
> > > > > > > > > > > > > > > > > > > > >> > is
> > > > > > > > > > > > > > > > > > > > >> > > a
> > > > > > > > > > > > > > > > > > > > >> > > > cleaner solution and I'd be
> > > happy
> > > > to
> > > > > > > > > > reconsider!
> > > > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > > > >> > > > Thanks,
> > > > > > > > > > > > > > > > > > > > >> > > > Yash
> > > > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > > > >> > > > On Thu, Sep 22, 2022 at
> 11:18
> > PM
> > > > > > Randall
> > > > > > > > > > Hauch <
> > > > > > > > > > > > > > > > > > > rhauch@gmail.com>
> > > > > > > > > > > > > > > > > > > > >> > wrote:
> > > > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > > > >> > > > > Hi, Yash. Thanks for
> picking
> > > up
> > > > > this
> > > > > > > KIP
> > > > > > > > > and
> > > > > > > > > > > > > > > discussion.
> > > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > > >> > > > > The KIP includes this
> > rejected
> > > > > > > > > alternative:
> > > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > > >> > > > > > 4. Update SinkTask.put
> in
> > > any
> > > > > way
> > > > > > to
> > > > > > > > > pass
> > > > > > > > > > > the
> > > > > > > > > > > > > new
> > > > > > > > > > > > > > > > > > > information
> > > > > > > > > > > > > > > > > > > > >> > outside
> > > > > > > > > > > > > > > > > > > > >> > > > > > SinkRecord (e.g. a Map
> or
> > a
> > > > > > derived
> > > > > > > > > class)
> > > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > > >> > > > > >    -
> > > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > > >> > > > > >    Much more disruptive
> > > change
> > > > > > > without
> > > > > > > > > > > > > > considerable
> > > > > > > > > > > > > > > > pros
> > > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > > >> > > > > One advantage about doing
> > this
> > > > is
> > > > > > that
> > > > > > > > > sink
> > > > > > > > > > > > > > connector
> > > > > > > > > > > > > > > > > > > > >> implementations
> > > > > > > > > > > > > > > > > > > > >> > > can
> > > > > > > > > > > > > > > > > > > > >> > > > > more easily implement two
> > > > > different
> > > > > > > > > > "put(...)"
> > > > > > > > > > > > > > methods
> > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > > handle
> > > > > > > > > > > > > > > > > > > > >> > > running
> > > > > > > > > > > > > > > > > > > > >> > > > in
> > > > > > > > > > > > > > > > > > > > >> > > > > a variety of runtimes,
> > without
> > > > > > having
> > > > > > > to
> > > > > > > > > use
> > > > > > > > > > > > > > try-catch
> > > > > > > > > > > > > > > > > logic
> > > > > > > > > > > > > > > > > > > > >> around
> > > > > > > > > > > > > > > > > > > > >> > the
> > > > > > > > > > > > > > > > > > > > >> > > > > newer SinkRecord access
> > > methods.
> > > > > > That
> > > > > > > > > latter
> > > > > > > > > > > > logic
> > > > > > > > > > > > > > can
> > > > > > > > > > > > > > > > get
> > > > > > > > > > > > > > > > > > > quite
> > > > > > > > > > > > > > > > > > > > >> > ugly.
> > > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > > >> > > > > For example, the existing
> > > `put`
> > > > > > method
> > > > > > > > has
> > > > > > > > > > > this
> > > > > > > > > > > > > > > > signature:
> > > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > > >> > > > > public abstract void
> > > > > > > > > > > put(Collection<SinkRecord>
> > > > > > > > > > > > > > > > records);
> > > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > > >> > > > > If we added an overloaded
> > > method
> > > > > > that
> > > > > > > > > passed
> > > > > > > > > > > in
> > > > > > > > > > > > a
> > > > > > > > > > > > > > map
> > > > > > > > > > > > > > > of
> > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > old
> > > > > > > > > > > > > > > > > > > > >> > > > > topic+partition for each
> > > record
> > > > > (and
> > > > > > > > > defined
> > > > > > > > > > > the
> > > > > > > > > > > > > > > absence
> > > > > > > > > > > > > > > > > of
> > > > > > > > > > > > > > > > > > an
> > > > > > > > > > > > > > > > > > > > >> entry
> > > > > > > > > > > > > > > > > > > > >> > as
> > > > > > > > > > > > > > > > > > > > >> > > > > having an unchanged topic
> > and
> > > > > > > > partition):
> > > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > > >> > > > > public void
> > > > > > put(Collection<SinkRecord>
> > > > > > > > > > > records,
> > > > > > > > > > > > > > > > > > > Map<SinkRecord,
> > > > > > > > > > > > > > > > > > > > >> > > > > TopicPartition>
> > > > > > > updatedTopicPartitions)
> > > > > > > > {
> > > > > > > > > > > > > > > > > > > > >> > > > > put(records);
> > > > > > > > > > > > > > > > > > > > >> > > > > }
> > > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > > >> > > > > then a `SinkTask`
> > > implementation
> > > > > > that
> > > > > > > > > wants
> > > > > > > > > > to
> > > > > > > > > > > > use
> > > > > > > > > > > > > > > this
> > > > > > > > > > > > > > > > > new
> > > > > > > > > > > > > > > > > > > > >> feature
> > > > > > > > > > > > > > > > > > > > >> > > could
> > > > > > > > > > > > > > > > > > > > >> > > > > simply implement both
> > methods:
> > > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > > >> > > > > public void
> > > > > > put(Collection<SinkRecord>
> > > > > > > > > > > records)
> > > > > > > > > > > > {
> > > > > > > > > > > > > > > > > > > > >> > > > > // Running in an older
> > > runtime,
> > > > so
> > > > > > no
> > > > > > > > > > tracking
> > > > > > > > > > > > of
> > > > > > > > > > > > > > > > > > SMT-modified
> > > > > > > > > > > > > > > > > > > > >> topic
> > > > > > > > > > > > > > > > > > > > >> > > > names
> > > > > > > > > > > > > > > > > > > > >> > > > > or partitions
> > > > > > > > > > > > > > > > > > > > >> > > > > put(records, Map.of());
> > > > > > > > > > > > > > > > > > > > >> > > > > }
> > > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > > >> > > > > public void
> > > > > > put(Collection<SinkRecord>
> > > > > > > > > > > records,
> > > > > > > > > > > > > > > > > > > Map<SinkRecord,
> > > > > > > > > > > > > > > > > > > > >> > > > > TopicPartition>
> > > > > > > updatedTopicPartitions)
> > > > > > > > {
> > > > > > > > > > > > > > > > > > > > >> > > > > // real logic here
> > > > > > > > > > > > > > > > > > > > >> > > > > }
> > > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > > >> > > > > This seems a lot easier
> than
> > > > > having
> > > > > > to
> > > > > > > > use
> > > > > > > > > > > > > try-catch
> > > > > > > > > > > > > > > > > logic,
> > > > > > > > > > > > > > > > > > > yet
> > > > > > > > > > > > > > > > > > > > >> still
> > > > > > > > > > > > > > > > > > > > >> > > > > allows sink connectors to
> > > > utilize
> > > > > > the
> > > > > > > > new
> > > > > > > > > > > > > > > functionality
> > > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > > still
> > > > > > > > > > > > > > > > > > > > >> > work
> > > > > > > > > > > > > > > > > > > > >> > > > with
> > > > > > > > > > > > > > > > > > > > >> > > > > older Connect runtimes.
> > > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > > >> > > > > WDYT?
> > > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > > >> > > > > Randall
> > > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > > >> > > > > On Thu, Sep 8, 2022 at
> 7:03
> > AM
> > > > > Yash
> > > > > > > > Mayya
> > > > > > > > > <
> > > > > > > > > > > > > > > > > > > yash.mayya@gmail.com
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > >> > > wrote:
> > > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > > >> > > > > > Hi all,
> > > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > > >> > > > > > I would like to
> (re)start
> > a
> > > > new
> > > > > > > > > discussion
> > > > > > > > > > > > > thread
> > > > > > > > > > > > > > on
> > > > > > > > > > > > > > > > > > KIP-793
> > > > > > > > > > > > > > > > > > > > >> (Kafka
> > > > > > > > > > > > > > > > > > > > >> > > > > > Connect) which proposes
> > some
> > > > > > > additions
> > > > > > > > > to
> > > > > > > > > > > the
> > > > > > > > > > > > > > public
> > > > > > > > > > > > > > > > > > > > SinkRecord
> > > > > > > > > > > > > > > > > > > > >> > > > interface
> > > > > > > > > > > > > > > > > > > > >> > > > > > in order to support
> topic
> > > > > mutating
> > > > > > > > SMTs
> > > > > > > > > > for
> > > > > > > > > > > > sink
> > > > > > > > > > > > > > > > > > connectors
> > > > > > > > > > > > > > > > > > > > >> that do
> > > > > > > > > > > > > > > > > > > > >> > > > their
> > > > > > > > > > > > > > > > > > > > >> > > > > > own offset tracking.
> > > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > > >> > > > > > Links:
> > > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > > >> > > > > > KIP:
> > > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=191336830
> > > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > > >> > > > > > Older discussion thread:
> > > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >
> > > > > > > > > >
> > > > https://lists.apache.org/thread/00kcth6057jdcsyzgy1x8nb2s1cymy8h
> > > > > > > > > > > ,
> > > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >
> > > > > > > > > >
> > > > https://lists.apache.org/thread/rzqkm0q5y5v3vdjhg8wqppxbkw7nyopj
> > > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > > >> > > > > > Jira:
> > > > > > > > > > > > > > > >
> > > https://issues.apache.org/jira/browse/KAFKA-13431
> > > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > > >> > > > > > Thanks,
> > > > > > > > > > > > > > > > > > > > >> > > > > > Yash
> > > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
>

Re: [DISCUSS] KIP-793: Sink Connectors: Support topic-mutating SMTs for async connectors (preCommit users)

[Yash Mayya <ya...@gmail.com>]

Hi Chris,

Firstly, thanks for sharing your detailed thoughts on this thorny issue!
Point taken on Kafka Connect being a brownfield project and I guess we
might just need to trade off elegant / "clean" interfaces for fixing this
gap in functionality. Also, thanks for calling out all the existing
cross-plugin interactions and also the fact that connectors are not and
should not be developed in silos ignoring the rest of the ecosystem. That
said, here are my thoughts:

> we could replace these methods with headers that the
> Connect runtime automatically injects into records directly
> before dispatching them to SinkTask::put.

Hm, that's an interesting idea to get around the need for connectors to
handle potential 'NoSuchMethodError's in calls to
SinkRecord::originalTopic/originalKafkaPartition/originalKafkaOffset.
However, I'm inclined to agree that retrieving these values from the record
headers seems even less intuitive and I'm okay with adding this to the
rejected alternatives list.

> we can consider eliminating the overridden
> SinkTask::open/close methods

I tried to further explore the idea of keeping just the existing
SinkTask::open / SinkTask::close methods but only calling them with
post-transform topic partitions and ended up coming to the same conclusion
that you did earlier in this thread :)

The overloaded SinkTask::open / SinkTask::close are currently the biggest
sticking points with the latest iteration of this KIP and I'd prefer this
elimination for now. The primary reasoning is that the information from
open / close on pre-transform topic partitions can be combined with the per
record information of both pre-transform and post-transform topic
partitions to handle most practical use cases without significantly
muddying the sink connector related public interfaces. The argument that
this makes it harder for sink connectors to deal with post-transform topic
partitions (i.e. in terms of grouping together or batching records for
writing to the sink system) can be countered with the fact that it'll be
similarly challenging even with the overloaded method approach of calling
open / close with both pre-transform and post-transform topic partitions
since the batching would be done on post-transform topic partitions whereas
offset tracking and reporting for commits would be done on pre-transform
topic partitions (and the two won't necessarily serially advance in
lockstep). On a side note, this also means that the per sink record ack API
that was proposed earlier wouldn't really work for this case since Kafka
consumers themselves don't support per message acknowledgement semantics
(and any sort of manual book-keeping based on offset linearity in a topic
partition would be affected by things like log compaction, control records
for transactional use cases etc.) right? Overall, I think that the only
benefit of the overloaded open / close methods approach is that the
framework can enable the eventual closure of any post-transform topic
partition based writers created by sink tasks using the heuristics we
discussed earlier (via a cache with a time-based eviction policy) which
doesn't seem worth it at this point.

Thanks,
Yash

On Mon, May 22, 2023 at 7:30 PM Chris Egerton <ch...@aiven.io.invalid>
wrote:

> Hi Yash,
>
> I've been following the discussion and have some thoughts. Ultimately I'm
> still in favor of this KIP and would hate to see it go dormant, though we
> may end up settling for a less-invasive option.
>
>
> On the topic of abstraction and inter-plugin interactions:
>
> First, there already are instances of cross-plugin interactions. Logical
> type handling is probably the biggest example: a source connector embeds
> metadata in the schema for record keys/values it emits that notifies
> downstream converters about how to handle them. We provide support for some
> logical types in Connect out of the box, but there's nothing stopping
> connector and converter developers from implementing their own logical type
> support using the exact same mechanism and different logical type names,
> which is already done by Debezium, to name one example.
>
> Second, although it's been a goal of Connect to abstract away parts of
> building a data pipeline so that, e.g., connector developers don't have to
> be concerned with converters or consumers, in reality, this layer of
> abstraction has already been eroded. The example that most-readily comes to
> mind is how source tasks are notified of the offsets of records that
> they've emitted after they've been published to Kafka via
> SourceTask::commitRecord [1].
>
> But, more importantly, it's unlikely that connectors are being developed in
> complete isolation. Nobody's going to implement the SinkConnector /
> SinkTask interfaces and then throw that code off to someone else to figure
> out all the details of deployment, configuration, testing, etc. Developers
> will probably have to be aware of at least the converter interface, some of
> the available implementations of it, and some details of Kafka clients
> (e.g., consumer groups for sink connectors). And this isn't a bad
> thing--it's unlikely that someone will write a Kafka connector without
> having or benefitting from some understanding of Kafka and the steps of the
> data pipeline that it will be a part of.
>
> Bringing this to the practical topic of discussion--transformations--I
> think it's actually in everyone's best interests for connector developers
> to be aware of transformations. This isn't just because of the specific
> problem that the KIP is trying to address. It's because there's plenty of
> logic that can be implemented via SMT that a naive connector developer will
> think that they have to implement on their own, which will ultimately lead
> to a sub-par experience for people who end up using those connectors due to
> inconsistent semantics (especially lack of predicates), inconsistent
> configuration syntax, increased chances for bugs, and FUD ("why wasn't this
> implemented as an SMT?").
>
> Finally, although preserving clean, composable interfaces that can be
> understood in isolation is a great principle to start with, we are now in
> what Anna McDonald recently referred to as "brownfield" space for Connect.
> We can't go back in time and redesign the SMT interface/contracts to make
> things cleaner. And I don't think it's fair to anyone to suddenly drop
> support for SMTs that mutate t/p/o information for sink records, especially
> since these can be used gainfully with plenty of existing sink connectors.
>
> Ultimately I still think the path forward that's best for the users is to
> make the impossible possible by addressing this long-standing API gap in
> Connect. Yes, it adds to the cognitive burden for connector developers, but
> if they can tolerate it, the end result is better for everyone involved,
> and if they can't, it's likely that the end result will be a preservation
> of existing behavior, which leaves us no worse than before.
>
>
> With all that said, I've thought about how to minimize or at least hide the
> API changes as much as possible. I've had two thoughts:
>
> 1. On the
> SinkRecord::originalTopic/originalKafkaPartition/originalKafkaOffset front,
> we could replace these methods with headers that the Connect runtime
> automatically injects into records directly before dispatching them to
> SinkTask::put. The names can be the proposed method names (e.g.,
> "originalTopic"). I believe this is inferior to the current proposal and
> should be a rejected alternative, but it at least seemed worth floating in
> the name of compromise. I dislike this approach for two reasons: first, it
> seems even less intuitive, and second, it doesn't come with the benefit of
> encouraging connector developers to understand the SMT interface and take
> it into account when designing connectors.
>
> 2. Although I'd hate to see the same bookkeeping logic implemented in
> multiple connectors, we can consider eliminating the overridden
> SinkTask::open/close methods. A note should be added to both methods
> clarifying that they are only invoked with the original, pre-transform
> topic partitions, and developers will be on their own if they want to deal
> with post-transform topic partitions instead. I'm on the fence with this
> one, but if it's a choice between passing this KIP without modifying
> SinkTask::open/close, or letting the KIP go dormant, I'd happily choose the
> former.
>
> Thanks Yash and Greg for the discussion so far, and apologies for the wall
> of text. Looking forward to your thoughts.
>
> Cheers,
>
> Chris
>
> [1] -
>
> https://kafka.apache.org/34/javadoc/org/apache/kafka/connect/source/SourceTask.html#commitRecord(org.apache.kafka.connect.source.SourceRecord,org.apache.kafka.clients.producer.RecordMetadata)
>
> On Sun, Apr 23, 2023 at 11:20 AM Yash Mayya <ya...@gmail.com> wrote:
>
> > Hi Greg,
> >
> > Thanks for the response and sorry for the late reply.
> >
> > > Currently the AK tests have a lot of calls to, for example, new
> > > SinkRecord(String topic, int partition, Schema keySchema,
> > > Object key, Schema valueSchema, Object value, long kafkaOffset)
> > > , a constructor without the original T/P/O values. I assumed that for
> > > backwards compatibility these constructors would still be usable in
> > > new runtimes. I imagine that there are also tests in downstream
> projects
> > > which make use of these constructors, whenever a Transform, Predicate,
> > > or Task is tested without a corresponding Converter. My question was
> > > about what values are chosen for the original T/P/O methods when these
> > > constructors are used after an upgrade to the latest connect-api.
> >
> > That's a good question - since this should only primarily affect testing
> I
> > think it should be acceptable to simply use the topic, partition and
> > kafkaOffset values as the originalTopic, originalKafkaPartition
> > and originalKafkaOffset?
> >
> > > If you inject the original T/P/O only before and after the chain, SMTs
> > > after an SMT which changes the original T/P/O will see whatever the
> > earlier
> > > SMT emitted. Is this intentional, or should this be avoided?
> >
> > Hmm, this sounds like a misbehaving / badly implemented SMTs since there
> > doesn't seem to be any reasonable situation where an SMT should modify a
> > sink record's original topic / partition / offset data so I'm not in
> favor
> > of introducing checks and guards in the framework for this.
> >
> > Another point that I've been pondering about is the one you raised about
> > the composability of Connect's plugin ecosystem and the special case
> > handling we're adding to sink connector plugins to work with certain
> > transformation plugin types. This really doesn't seem like a good
> precedent
> > to be setting / starting (since there don't seem to be any other such
> > "snowflake" inter-plugin interactions) in my opinion. The alternative of
> > completely managing this in the framework (and only exposing the virtual
> > coordinates to the sink tasks) doesn't seem too appealing either due to
> the
> > backward compatibility concerns while maintaining existing support and
> > functionality such as the possibility of implementing exactly-once
> > semantics, ability for tasks to rewind consumer offsets arbitrarily
> (which
> > might require the introduction of some form of persistence for the
> physical
> > <-> virtual coordinate mapping) etc. Unfortunately, even though this is a
> > long standing problem that all of us want to fix, I'm considering moving
> > this KIP into a dormant / inactive state since there doesn't seem to be a
> > design that satisfies all the general principles that the Kafka Connect
> > framework has striven to uphold.
> >
> > Thanks,
> > Yash
> >
> > On Tue, Mar 14, 2023 at 3:31 AM Greg Harris <greg.harris@aiven.io.invalid
> >
> > wrote:
> >
> > > Yash,
> > >
> > > > 'm not sure I follow - are you asking about how the tests will be
> > updated
> > > post this change or about how upgrades will look like for clusters in
> > > production?
> > >
> > > Currently the AK tests have a lot of calls to, for example, new
> > > SinkRecord(String topic, int partition, Schema keySchema, Object key,
> > > Schema valueSchema, Object value, long kafkaOffset), a constructor
> > without
> > > the original T/P/O values. I assumed that for backwards compatibility
> > these
> > > constructors would still be usable in new runtimes.
> > > I imagine that there are also tests in downstream projects which make
> use
> > > of these constructors, whenever a Transform, Predicate, or Task is
> tested
> > > without a corresponding Converter. My question was about what values
> are
> > > chosen for the original T/P/O methods when these constructors are used
> > > after an upgrade to the latest connect-api.
> > >
> > > > There shouldn't be any difference in behavior here - the framework
> will
> > > add
> > > the original T/P/O metadata to the record after the entire
> transformation
> > > chain has been applied and just before sending the record to the task
> for
> > > processing. The KIP doesn't propose that transformations themselves
> > should
> > > also be able to retrieve original T/P/O information for a sink record.
> > >
> > > The KIP includes this: "Note that while the record's offset can't be
> > > modified via the standard SinkRecord::newRecord methods that SMTs are
> > > expected to use, SinkRecord has public constructors that would allow
> SMTs
> > > to return records with modified offsets. This is why the proposed
> changes
> > > include a new SinkRecord::originalKafkaOffset method as well."
> > > In order to use the new or old SinkRecord constructors outside of the
> > > newRecord methods, SMTs will downcast the previous record and may
> access
> > > the original T/P/O methods. They may or may not forward this to the
> next
> > > SMT, and they may or may not use it in their own computation.
> > > Since this is acknowledged as a possible implementation, I was just
> > asking
> > > about when one SMT changes the original T/P/O, what should later SMTs
> and
> > > predicates see from the original T/P/O methods?
> > > If you inject the original T/P/O only before and after the chain, SMTs
> > > after an SMT which changes the original T/P/O will see whatever the
> > earlier
> > > SMT emitted. Is this intentional, or should this be avoided?
> > > For existing SMTs use the SinkRecord constructor, either directly or
> via
> > > subclasses of ConnectRecord, they will drop the original T/P/O and fall
> > > back to the logic from question (1).
> > >
> > > > The rejected alternative basically says that we can't do a
> > > deterministic mapping from virtual coordinates to physical coordinates
> > > without doing a lot of book-keeping.
> > >
> > > I suppose there is a possible implementation of metadata book-keeping
> > which
> > > provides a reasonable system of virtual coordinates, it just ended up
> > > equivalent to hydrating intermediate topics to compute a consistent
> > record
> > > ordering. I wasn't convinced by calling it "book-keeping" since i've
> seen
> > > that phrase used to disregard much less complicated state management,
> and
> > > had to see exactly where that solution becomes unreasonable.
> > >
> > > Thanks,
> > > Greg
> > >
> > > On Sun, Mar 12, 2023 at 6:30 AM Yash Mayya <ya...@gmail.com>
> wrote:
> > >
> > > > Hi Greg,
> > > >
> > > > Thanks for the detailed review!
> > > >
> > > > > What is the expected state/behavior for SinkRecords
> > > > > which do not have original T/P/O information after the
> > > > > upgrade? Just browsing, it appears that tests make
> > > > > extensive use of the existing public SinkRecord
> > > > > constructors  for both Transformations and Connectors.
> > > >
> > > > I'm not sure I follow - are you asking about how the tests will be
> > > updated
> > > > post this change or about how upgrades will look like for clusters in
> > > > production? For the latter, we won't have to worry about sink records
> > > > without original T/P/O information at all once a cluster is fully
> > rolled
> > > > and we will make it (hopefully) abundantly clear that connectors need
> > to
> > > > account for missing original T/P/O getter methods if they expect to
> be
> > > > deployed on older Connect runtimes.
> > > >
> > > > > What is the expected behavior for Transformation
> > > > > implementations which do not use the newRecord
> > > > > methods and instead use public SinkRecord constructors?
> > > > > The KIP mentions this as a justification for the
> > > > > originalKafkaOffset method, but if existing implementations
> > > > > are using the existing constructors, those constructors won't
> > > > > forward the original T/P/O information to later transforms or
> > > > > the task.
> > > >
> > > > There shouldn't be any difference in behavior here - the framework
> will
> > > add
> > > > the original T/P/O metadata to the record after the entire
> > transformation
> > > > chain has been applied and just before sending the record to the task
> > for
> > > > processing. The KIP doesn't propose that transformations themselves
> > > should
> > > > also be able to retrieve original T/P/O information for a sink
> record.
> > > >
> > > > > This reasoning and the KIP design seems to imply that the
> > > > > connector is better equipped to solve this problem than the
> > > > > framework, but the stated reasons are not convincing for me.
> > > >
> > > > This was added to the KIP by the original author, but I don't think
> the
> > > > intention was to imply that the connector is better equipped to solve
> > > this
> > > > problem than the framework. The intention is to provide complete
> > > > information to the connector ("physical" and "virtual coordinates"
> > > instead
> > > > of the currently incomplete "virtual coordinates" as you've termed
> it)
> > so
> > > > that connectors can use the virtual coordinates for writing data to
> the
> > > > sink system and physical coordinates for offset reporting back to the
> > > > framework. The rejected alternative basically says that we can't do a
> > > > deterministic mapping from virtual coordinates to physical
> coordinates
> > > > without doing a lot of book-keeping.
> > > >
> > > > I agree with the rest of your analysis on the tradeoffs between the
> > > > proposed approach versus the seemingly more attractive approach of
> > > handling
> > > > everything purely in the framework and only exposing "virtual
> > > coordinates"
> > > > to the connectors. I think the biggest thorn here is maintaining
> > backward
> > > > compatibility with the considerable ecosystem of existing connectors
> > > which
> > > > is something Connect has always been burdened by.
> > > >
> > > > Thanks,
> > > > Yash
> > > >
> > > > On Wed, Mar 8, 2023 at 6:54 AM Greg Harris
> > <greg.harris@aiven.io.invalid
> > > >
> > > > wrote:
> > > >
> > > > > Hi Yash,
> > > > >
> > > > > I always use this issue as an example of a bug being caused by
> design
> > > > > rather than by implementation error, and once it's fixed I'll need
> to
> > > > find
> > > > > something else to talk about :)
> > > > > So glad to see this get fixed!
> > > > >
> > > > > I'll chime in to support some of the earlier discussions that seem
> to
> > > > have
> > > > > been resolved:
> > > > >
> > > > > 1. With respect to SinkRecord methods vs an overloaded put(): I
> agree
> > > > with
> > > > > the current design but I justify it a little bit differently than
> has
> > > > > already been discussed.
> > > > > If we were designing this interface on day 1 without backwards
> > > > > compatibility in mind, which design would make more sense? Or for a
> > > > > different framing: In the future when old runtimes and connectors
> are
> > > > > retired and the old interfaces are removed, which design is going
> to
> > > look
> > > > > more strange and unmotivated?
> > > > > Applied to this design decision, I would say that the original
> T/P/O
> > > are
> > > > > properties of a single SinkRecord and make sense as getters, and it
> > > would
> > > > > be strange to store them in an auxiliary map.
> > > > >
> > > > > 2. Following up this change with a compatibility library to make
> the
> > > > > interface easier to use is the right choice to make here. This
> change
> > > > > should be focused on correctness in allowing developers to fix the
> > > > > incompatibility and we can be concerned with coming up with a more
> > > > > ergonomic solution in the compatibility library.
> > > > > The API should be focused on generality, correctness, and
> performance
> > > > > because those cannot be worked-around after the fact. Connector
> > > > > implementations and/or libraries can be concerned with trading off
> > some
> > > > > generality and/or performance for ease-of-use.
> > > > >
> > > > > 3. I think that the difference in behavior of the new open/close
> > > methods
> > > > as
> > > > > compared to the old methods is significant, and requires good
> > > > documentation
> > > > > to help connector developers avoid lazy and incorrect migrations. I
> > am
> > > > > happy to have that addressed in code review after the KIP is
> > approved.
> > > > >
> > > > > I had some questions:
> > > > >
> > > > > 4. What is the expected state/behavior for SinkRecords which do not
> > > have
> > > > > original T/P/O information after the upgrade? Just browsing, it
> > appears
> > > > > that tests make extensive use of the existing public SinkRecord
> > > > > constructors for both Transformations and Connectors.
> > > > >
> > > > > 5. What is the expected behavior for Transformation implementations
> > > which
> > > > > do not use the newRecord methods and instead use public SinkRecord
> > > > > constructors? The KIP mentions this as a justification for the
> > > > > originalKafkaOffset method, but if existing implementations are
> using
> > > the
> > > > > existing constructors, those constructors won't forward the
> original
> > > > T/P/O
> > > > > information to later transforms or the task.
> > > > >
> > > > > For the last few points, I want to discuss this rejected
> alternative:
> > > > >
> > > > > > Address the offsets problem entirely within the framework, doing
> > some
> > > > > kind of mapping from the transformed topic back to the original
> > topic.
> > > > > > * This would only work in the cases where there’s no overlap
> > between
> > > > the
> > > > > transformed topic names, but would break for the rest of the
> > > > > transformations (e.g. static transformation, topic = “a”).
> > > > > > * Even if we wanted to limit the support to those cases, it would
> > > > require
> > > > > considerable bookkeeping to add a validation to verify that the
> > > > > transformation chain adheres to that expectation (and fail fast if
> it
> > > > > doesn’t).
> > > > >
> > > > > 6. This reasoning and the KIP design seems to imply that the
> > connector
> > > is
> > > > > better equipped to solve this problem than the framework, but the
> > > stated
> > > > > reasons are not convincing for me.
> > > > > * A static transformation still causes an offset collision in the
> > > > connector
> > > > > * The connector is not permitted to see the transformation chain to
> > do
> > > > any
> > > > > fail-fast assertions
> > > > >
> > > > > Suppose we were to think of the records at the end of the
> > > transformation
> > > > > chain as being in "virtual partitions" with "virtual offsets".
> > > > > For example, with identity-routing SMTs, the virtual coordinates
> are
> > > > > exactly the same as the underlying physical coordinates. For 1-1
> > > renames,
> > > > > each virtual topic would be the renamed topic corresponding to the
> > > > > underlying topic. For fan-out from one topic to multiple virtual
> > > topics,
> > > > > virtual offsets would use the underlying kafka offsets with gaps
> for
> > > > > records going to other virtual partitions. Virtual topics with
> > dropped
> > > > > records have similar gaps in the offsets.
> > > > > Currently, these virtual coordinates are passed into the connector
> > via
> > > > > SinkTask::put, but SinkTask::open/close/preCommit and
> > > > > SinkTaskContext::assignment/offsets/pause/resume all use physical
> > > > > coordinates.
> > > > > This proposal patches put,open, and close to have both physical and
> > > > virtual
> > > > > coordinates, but leaves the other methods with physical
> coordinates.
> > > > After
> > > > > this proposal, connectors would be intentionally made aware of the
> > > > > distinction between physical and virtual coordinates, and manage
> > their
> > > > own
> > > > > bookkeeping for the two systems.
> > > > >
> > > > > To avoid that connector logic, we could use virtual coordinates in
> > all
> > > > > connector calls, never revealing that they are different from the
> > > > physical
> > > > > coordinates. There's a whole design shopping list that we'd need:
> > > > > * Renumbering mechanism for disambiguating and making virtual
> offsets
> > > > > monotonic in the case of topic/partition collisions
> > > > > * Data structure and strategy for translating virtual offsets back
> to
> > > > > physical offsets
> > > > > * New limits on SinkTaskContext::offsets() calls to prevent
> rewinding
> > > > > before the latest commit
> > > > > * Backwards compatibility and upgrade design
> > > > >
> > > > > 7. This alternative was very appealing to me, because the strength
> > of a
> > > > > plugin framework is the composability of different components.
> Among
> > a
> > > > > collection of N connectors and M transforms, it should ideally only
> > > take
> > > > > N + M work to understand how the components combine to build the
> > whole.
> > > > > However, once you start adding special cases to some plugins to
> > support
> > > > > interactions with others, the whole system can take N * M work to
> > > > > understand. From a complexity standpoint, it would be very good for
> > the
> > > > > framework to solve this in a way which was connector-agnostic.
> > > > > The current design compromises the logical isolation of the plugins
> > > > > slightly, but they can collapse offsets very memory-efficiently,
> and
> > > > re-use
> > > > > the existing raw coordinate functions and keep everything else
> > > backwards
> > > > > compatible. After deriving all of the above, I think that's a
> > > reasonable
> > > > > tradeoff to make.
> > > > >
> > > > > Thanks,
> > > > > Greg
> > > > >
> > > > > On Tue, Feb 21, 2023 at 10:17 AM Chris Egerton
> > <chrise@aiven.io.invalid
> > > >
> > > > > wrote:
> > > > >
> > > > > > Hi Yash,
> > > > > >
> > > > > > We'll probably want to make a few tweaks to the Javadocs for the
> > new
> > > > > > methods (I'm imagining that notes on compatibility with older
> > > versions
> > > > > will
> > > > > > be required), but I believe what's proposed in the KIP is good
> > enough
> > > > to
> > > > > > approve with the understanding that it may not exactly match what
> > > gets
> > > > > > implemented/merged.
> > > > > >
> > > > > > LGTM, thanks again for the KIP!
> > > > > >
> > > > > > Cheers,
> > > > > >
> > > > > > Chris
> > > > > >
> > > > > > On Tue, Feb 21, 2023 at 12:18 PM Yash Mayya <
> yash.mayya@gmail.com>
> > > > > wrote:
> > > > > >
> > > > > > > Hi Chris,
> > > > > > >
> > > > > > > > we might try to introduce a framework-level configuration
> > > > > > > > property to dictate which of the pre-transform and
> > post-transform
> > > > > > > > topic partitions are used for the fallback call to the
> > single-arg
> > > > > > > > variant if a task class has not overridden the multi-arg
> > variant
> > > > > > >
> > > > > > > Thanks for the explanation and I agree that this will be a tad
> > bit
> > > > too
> > > > > > > convoluted. :)
> > > > > > >
> > > > > > > Please do let me know if you'd like any further amendments to
> the
> > > > KIP!
> > > > > > >
> > > > > > > Thanks,
> > > > > > > Yash
> > > > > > >
> > > > > > > On Tue, Feb 21, 2023 at 8:42 PM Chris Egerton
> > > > <chrise@aiven.io.invalid
> > > > > >
> > > > > > > wrote:
> > > > > > >
> > > > > > > > Hi Yash,
> > > > > > > >
> > > > > > > > I think the use case for pre-transform TPO coordinates (and
> > topic
> > > > > > > partition
> > > > > > > > writers created/destroyed in close/open) tends to boil down
> to
> > > > > > > exactly-once
> > > > > > > > semantics, where it's desirable to preserve the guarantees
> that
> > > > Kafka
> > > > > > > > provides (every record has a unique TPO trio, and records are
> > > > ordered
> > > > > > by
> > > > > > > > offset within a topic partition).
> > > > > > > >
> > > > > > > > It's my understanding that this approach is utilized in
> several
> > > > > > > connectors
> > > > > > > > out there today, and it might break these connectors to start
> > > using
> > > > > the
> > > > > > > > post-transform topic partitions automatically in their
> > open/close
> > > > > > > methods.
> > > > > > > >
> > > > > > > > If we want to get really fancy with this and try to obviate
> or
> > at
> > > > > least
> > > > > > > > reduce the need for per-connector code changes, we might try
> to
> > > > > > > introduce a
> > > > > > > > framework-level configuration property to dictate which of
> the
> > > > > > > > pre-transform and post-transform topic partitions are used
> for
> > > the
> > > > > > > fallback
> > > > > > > > call to the single-arg variant if a task class has not
> > overridden
> > > > the
> > > > > > > > multi-arg variant. But I think this is going a bit too far
> and
> > > > would
> > > > > > > prefer
> > > > > > > > to keep things simple(r) for now.
> > > > > > > >
> > > > > > > > Cheers,
> > > > > > > >
> > > > > > > > Chris
> > > > > > > >
> > > > > > > >
> > > > > > > > On Sun, Feb 19, 2023 at 2:34 AM Yash Mayya <
> > yash.mayya@gmail.com
> > > >
> > > > > > wrote:
> > > > > > > >
> > > > > > > > > Hi Chris,
> > > > > > > > >
> > > > > > > > > > I was actually envisioning something like `void
> > > > > > > > > > open(Collection<TopicPartition> originalPartitions,
> > > > > > > > > > Collection<TopicPartition> transformedPartitions)`
> > > > > > > > >
> > > > > > > > > Ah okay, this does make a lot more sense. Sorry, I think I
> > > > > > > misunderstood
> > > > > > > > > you earlier. I do agree with you that this seems better
> than
> > > > > > splitting
> > > > > > > it
> > > > > > > > > off into two new sets of open / close methods from a
> > complexity
> > > > > > > > standpoint.
> > > > > > > > >
> > > > > > > > > > Plus, if a connector is intentionally designed to use
> > > > > > > > > > pre-transformation topic partitions in its open/close
> > > > > > > > > > methods, wouldn't we just be trading one form of the
> > > > > > > > > >  problem for another by making this switch?
> > > > > > > > >
> > > > > > > > > On thinking about this a bit more, I'm not so convinced
> that
> > we
> > > > > need
> > > > > > to
> > > > > > > > > expose the pre-transform / original topic partitions in the
> > new
> > > > > open
> > > > > > /
> > > > > > > > > close methods. The purpose of the open / close methods is
> to
> > > > allow
> > > > > > sink
> > > > > > > > > tasks to allocate and deallocate resources for each topic
> > > > partition
> > > > > > > > > assigned to the task and the purpose of topic-mutating SMTs
> > is
> > > to
> > > > > > > > > essentially modify the source topic name from the point of
> > view
> > > > of
> > > > > > the
> > > > > > > > sink
> > > > > > > > > connector. Why would a sink connector ever need to or want
> to
> > > > > > allocate
> > > > > > > > > resources for pre-transform topic partitions? Is the
> argument
> > > > here
> > > > > > that
> > > > > > > > > since we'll be exposing both the pre-transform and
> > > post-transform
> > > > > > topic
> > > > > > > > > partitions per record, we should also expose the same info
> > via
> > > > > open /
> > > > > > > > close
> > > > > > > > > and allow sink connector implementations to disregard
> > > > > topic-mutating
> > > > > > > SMTs
> > > > > > > > > completely if they wanted to?
> > > > > > > > >
> > > > > > > > > Either way, I've gone ahead and updated the KIP to reflect
> > all
> > > of
> > > > > > > > > our previous discussion here since it had become quite
> > > outdated.
> > > > > I've
> > > > > > > > also
> > > > > > > > > updated the KIP title from "Sink Connectors: Support
> > > > topic-mutating
> > > > > > > SMTs
> > > > > > > > > for async connectors (preCommit users)" to "Allow sink
> > > connectors
> > > > > to
> > > > > > be
> > > > > > > > > used with topic-mutating SMTs" since the improvements to
> the
> > > > open /
> > > > > > > close
> > > > > > > > > mechanism doesn't pertain only to asynchronous sink
> > connectors.
> > > > The
> > > > > > new
> > > > > > > > KIP
> > > > > > > > > URL is:
> > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-793%3A+Allow+sink+connectors+to+be+used+with+topic-mutating+SMTs
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > Thanks,
> > > > > > > > > Yash
> > > > > > > > >
> > > > > > > > > On Tue, Feb 14, 2023 at 11:39 PM Chris Egerton
> > > > > > <chrise@aiven.io.invalid
> > > > > > > >
> > > > > > > > > wrote:
> > > > > > > > >
> > > > > > > > > > Hi Yash,
> > > > > > > > > >
> > > > > > > > > > I was actually envisioning something like `void
> > > > > > > > > > open(Collection<TopicPartition>
> > > > > > > > > > originalPartitions, Collection<TopicPartition>
> > > > > > > transformedPartitions)`,
> > > > > > > > > > since we already convert and transform each batch of
> > records
> > > > that
> > > > > > we
> > > > > > > > poll
> > > > > > > > > > from the sink task's consumer en masse, meaning we could
> > > > discover
> > > > > > > > several
> > > > > > > > > > new transformed partitions in between consecutive calls
> to
> > > > > > > > SinkTask::put.
> > > > > > > > > >
> > > > > > > > > > It's also worth noting that we'll probably want to
> > deprecate
> > > > the
> > > > > > > > existing
> > > > > > > > > > open/close methods, at which point keeping one
> > non-deprecated
> > > > > > variant
> > > > > > > > of
> > > > > > > > > > each seems more appealing and less complex than keeping
> > two.
> > > > > > > > > >
> > > > > > > > > > Honestly though, I think we're both on the same page
> enough
> > > > that
> > > > > I
> > > > > > > > > wouldn't
> > > > > > > > > > object to either approach. We've probably reached the
> > > > saturation
> > > > > > > point
> > > > > > > > > for
> > > > > > > > > > ROI here and as long as we provide developers a way to
> get
> > > the
> > > > > > > > > information
> > > > > > > > > > they need from the runtime and take care to add Javadocs
> > and
> > > > > update
> > > > > > > our
> > > > > > > > > > docs page (possibly including the connector development
> > > > > > quickstart),
> > > > > > > it
> > > > > > > > > > should be fine.
> > > > > > > > > >
> > > > > > > > > > At this point, it might be worth updating the KIP based
> on
> > > > recent
> > > > > > > > > > discussion so that others can see the latest proposal,
> and
> > we
> > > > can
> > > > > > > both
> > > > > > > > > take
> > > > > > > > > > a look and make sure everything looks good enough before
> > > > opening
> > > > > a
> > > > > > > vote
> > > > > > > > > > thread.
> > > > > > > > > >
> > > > > > > > > > Finally, I think you make a convincing case for a
> > time-based
> > > > > > eviction
> > > > > > > > > > policy. I wasn't thinking about the fairly common SMT
> > pattern
> > > > of
> > > > > > > > > deriving a
> > > > > > > > > > topic name from, e.g., a record field or header.
> > > > > > > > > >
> > > > > > > > > > Cheers,
> > > > > > > > > >
> > > > > > > > > > Chris
> > > > > > > > > >
> > > > > > > > > > On Tue, Feb 14, 2023 at 11:42 AM Yash Mayya <
> > > > > yash.mayya@gmail.com>
> > > > > > > > > wrote:
> > > > > > > > > >
> > > > > > > > > > > Hi Chris,
> > > > > > > > > > >
> > > > > > > > > > > > Plus, if a connector is intentionally designed to
> > > > > > > > > > > > use pre-transformation topic partitions in its
> > > > > > > > > > > > open/close methods, wouldn't we just be trading
> > > > > > > > > > > > one form of the problem for another by making this
> > > > > > > > > > > > switch?
> > > > > > > > > > >
> > > > > > > > > > > Thanks, this makes sense, and given that the KIP
> already
> > > > > > proposes a
> > > > > > > > way
> > > > > > > > > > for
> > > > > > > > > > > sink connector implementations to distinguish between
> > > > > > pre-transform
> > > > > > > > and
> > > > > > > > > > > post-transform topics per record, I think I'm convinced
> > > that
> > > > > > going
> > > > > > > > with
> > > > > > > > > > new
> > > > > > > > > > > `open()` / `close()` methods is the right approach.
> > > However,
> > > > I
> > > > > > > still
> > > > > > > > > feel
> > > > > > > > > > > like having overloaded methods will make it a lot less
> > > > > > unintuitive
> > > > > > > > > given
> > > > > > > > > > > that the two sets of methods would be different in
> terms
> > of
> > > > > when
> > > > > > > > > they're
> > > > > > > > > > > called and what arguments they are passed (also I'm
> > > presuming
> > > > > > that
> > > > > > > > the
> > > > > > > > > > > overloaded methods you're prescribing will only have a
> > > single
> > > > > > > > > > > `TopicPartition` rather than a
> > `Collection<TopicPartition>`
> > > > as
> > > > > > > their
> > > > > > > > > > > parameters). I guess my concern is largely around the
> > fact
> > > > that
> > > > > > it
> > > > > > > > > won't
> > > > > > > > > > be
> > > > > > > > > > > possible to distinguish between the overloaded methods'
> > use
> > > > > cases
> > > > > > > > just
> > > > > > > > > > from
> > > > > > > > > > > the method signatures. I agree that naming is going to
> be
> > > > > > difficult
> > > > > > > > > here,
> > > > > > > > > > > but I think that having two sets of
> `SinkTask::openXyz` /
> > > > > > > > > > > `SinkTask::closeXyz` methods will be less complicated
> to
> > > > > > understand
> > > > > > > > > from
> > > > > > > > > > a
> > > > > > > > > > > connector developer perspective (as compared to
> > overloaded
> > > > > > methods
> > > > > > > > with
> > > > > > > > > > > only differing documentation). Of your suggested
> > options, I
> > > > > think
> > > > > > > > > > > `openPreTransform` / `openPostTransform` are the most
> > > > > > > comprehensible
> > > > > > > > > > ones.
> > > > > > > > > > >
> > > > > > > > > > > > BTW, I wouldn't say that we can't make assumptions
> > > > > > > > > > > > about the relationships between pre- and
> > > > post-transformation
> > > > > > > > > > > >  topic partitions.
> > > > > > > > > > >
> > > > > > > > > > > I meant that the framework wouldn't be able to
> > > > > deterministically
> > > > > > > know
> > > > > > > > > > when
> > > > > > > > > > > to close a post-transform topic partition given that
> SMTs
> > > > could
> > > > > > use
> > > > > > > > > > > per-record data / metadata to manipulate the topic
> names
> > as
> > > > and
> > > > > > how
> > > > > > > > > > > required (which supports the suggestion to use an
> > eviction
> > > > > policy
> > > > > > > > based
> > > > > > > > > > > mechanism to call SinkTask::close for post-transform
> > topic
> > > > > > > > partitions).
> > > > > > > > > > >
> > > > > > > > > > > > We might utilize a policy that assumes a
> deterministic
> > > > > > > > > > > > mapping from the former to the latter, for example.
> > > > > > > > > > >
> > > > > > > > > > > Wouldn't this be making the assumption that SMTs only
> use
> > > the
> > > > > > topic
> > > > > > > > > name
> > > > > > > > > > > itself and no other data / metadata while computing the
> > new
> > > > > topic
> > > > > > > > name?
> > > > > > > > > > Are
> > > > > > > > > > > you suggesting that since this assumption could work
> for
> > a
> > > > > > majority
> > > > > > > > of
> > > > > > > > > > > SMTs, it might be more efficient overall in terms of
> > > reducing
> > > > > the
> > > > > > > > > number
> > > > > > > > > > of
> > > > > > > > > > > "false-positive" calls to
> `SinkTask::closePostTransform`
> > > (and
> > > > > > we'll
> > > > > > > > > also
> > > > > > > > > > be
> > > > > > > > > > > able to call `SinkTask::closePostTransform` immediately
> > > after
> > > > > > topic
> > > > > > > > > > > partitions are revoked from the consumer)? I was
> thinking
> > > > > > something
> > > > > > > > > more
> > > > > > > > > > > generic along the lines of a simple time based eviction
> > > > policy
> > > > > > that
> > > > > > > > > > > wouldn't be making any assumptions regarding the SMT
> > > > > > > implementations.
> > > > > > > > > > > Either way, I do like your earlier suggestion of
> keeping
> > > this
> > > > > > logic
> > > > > > > > > > > internal and not painting ourselves into a corner by
> > > > promising
> > > > > > any
> > > > > > > > > > > particular behavior in the KIP.
> > > > > > > > > > >
> > > > > > > > > > > Thanks,
> > > > > > > > > > > Yash
> > > > > > > > > > >
> > > > > > > > > > > On Tue, Feb 14, 2023 at 1:08 AM Chris Egerton
> > > > > > > > <chrise@aiven.io.invalid
> > > > > > > > > >
> > > > > > > > > > > wrote:
> > > > > > > > > > >
> > > > > > > > > > > > Hi Yash,
> > > > > > > > > > > >
> > > > > > > > > > > > I think the key difference between adding
> > > methods/overloads
> > > > > > > related
> > > > > > > > > to
> > > > > > > > > > > > SinkTask::open/SinkTask::close and SinkTask::put is
> > that
> > > > this
> > > > > > > isn't
> > > > > > > > > > > > auxiliary information that may or may not be useful
> to
> > > > > > connector
> > > > > > > > > > > > developers. It's actually critical for them to
> > understand
> > > > the
> > > > > > > > > > difference
> > > > > > > > > > > > between the two concepts here, even if they look very
> > > > > similar.
> > > > > > > And
> > > > > > > > > > yes, I
> > > > > > > > > > > > do believe that switching from pre-transform to
> > > > > post-transform
> > > > > > > > topic
> > > > > > > > > > > > partitions is too big a change in behavior here.
> Plus,
> > > if a
> > > > > > > > connector
> > > > > > > > > > is
> > > > > > > > > > > > intentionally designed to use pre-transformation
> topic
> > > > > > partitions
> > > > > > > > in
> > > > > > > > > > its
> > > > > > > > > > > > open/close methods, wouldn't we just be trading one
> > form
> > > of
> > > > > the
> > > > > > > > > problem
> > > > > > > > > > > for
> > > > > > > > > > > > another by making this switch?
> > > > > > > > > > > >
> > > > > > > > > > > > One possible alternative to overloading the existing
> > > > methods
> > > > > is
> > > > > > > to
> > > > > > > > > > split
> > > > > > > > > > > > SinkTask::open into openOriginal (or possibly
> > > openPhysical
> > > > or
> > > > > > > > > > > > openPreTransform) and openTransformed (or openLogical
> > or
> > > > > > > > > > > > openPostTransform), with a similar change for
> > > > > SinkTask::close.
> > > > > > > The
> > > > > > > > > > > default
> > > > > > > > > > > > implementation for SinkTask::openOriginal can be to
> > call
> > > > > > > > > > SinkTask::open,
> > > > > > > > > > > > and the same can go for SinkTask::close. However, I
> > > prefer
> > > > > > > > > overloading
> > > > > > > > > > > the
> > > > > > > > > > > > existing methods since this alternative increases
> > > > complexity
> > > > > > and
> > > > > > > > none
> > > > > > > > > > of
> > > > > > > > > > > > the names are very informative.
> > > > > > > > > > > >
> > > > > > > > > > > > BTW, I wouldn't say that we can't make assumptions
> > about
> > > > the
> > > > > > > > > > > relationships
> > > > > > > > > > > > between pre- and post-transformation topic
> partitions.
> > We
> > > > > might
> > > > > > > > > > utilize a
> > > > > > > > > > > > policy that assumes a deterministic mapping from the
> > > former
> > > > > to
> > > > > > > the
> > > > > > > > > > > latter,
> > > > > > > > > > > > for example. The distinction I'd draw is that the
> > > > assumptions
> > > > > > we
> > > > > > > > make
> > > > > > > > > > can
> > > > > > > > > > > > and probably should favor some cases in terms of
> > > > performance
> > > > > > > (i.e.,
> > > > > > > > > > > > reducing the number of unnecessary calls to
> close/open
> > > > over a
> > > > > > > given
> > > > > > > > > > sink
> > > > > > > > > > > > task's lifetime), but should not lead to guaranteed
> > > > resource
> > > > > > > leaks
> > > > > > > > or
> > > > > > > > > > > > failure to obey API contract in any cases.
> > > > > > > > > > > >
> > > > > > > > > > > > Cheers,
> > > > > > > > > > > >
> > > > > > > > > > > > Chris
> > > > > > > > > > > >
> > > > > > > > > > > > On Mon, Feb 13, 2023 at 10:54 AM Yash Mayya <
> > > > > > > yash.mayya@gmail.com>
> > > > > > > > > > > wrote:
> > > > > > > > > > > >
> > > > > > > > > > > > > Hi Chris,
> > > > > > > > > > > > >
> > > > > > > > > > > > > > especially if connectors are intentionally
> designed
> > > > > around
> > > > > > > > > > > > > > original topic partitions instead of transformed
> > > ones.
> > > > > > > > > > > > >
> > > > > > > > > > > > > Ha, that's a good point and reminds me of Hyrum's
> Law
> > > [1]
> > > > > :)
> > > > > > > > > > > > >
> > > > > > > > > > > > > > I think we have to provide connector developers
> > with
> > > > some
> > > > > > > > > > > > > > way to differentiate between the two, but maybe
> > > > there's a
> > > > > > way
> > > > > > > > > > > > > >  to do this that I haven't thought of yet
> > > > > > > > > > > > >
> > > > > > > > > > > > > I can't think of a better way to do this either;
> > would
> > > > > > invoking
> > > > > > > > the
> > > > > > > > > > > > > existing `SinkTask::open` and `SinkTask::close`
> > methods
> > > > > with
> > > > > > > > > > > > post-transform
> > > > > > > > > > > > > topic partitions instead of pre-transform topic
> > > > partitions
> > > > > > not
> > > > > > > be
> > > > > > > > > > > > > acceptable even in a minor / major AK release? I
> feel
> > > > like
> > > > > > the
> > > > > > > > > > proposed
> > > > > > > > > > > > > approach of adding overloaded `SinkTask::open` /
> > > > > > > > `SinkTask::close`
> > > > > > > > > > > > methods
> > > > > > > > > > > > > to differentiate between pre-transform and
> > > post-transform
> > > > > > topic
> > > > > > > > > > > > partitions
> > > > > > > > > > > > > has similar pitfalls to the idea of the overloaded
> > > > > > > > `SinkTask::put`
> > > > > > > > > > > method
> > > > > > > > > > > > > we discarded earlier.
> > > > > > > > > > > > >
> > > > > > > > > > > > > > Either way, I'm glad that the general idea of a
> > cache
> > > > and
> > > > > > > > > > > > > > eviction policy for SinkTask::close seem
> > reasonable;
> > > if
> > > > > > > > > > > > > > we decide to go this route, it might make sense
> for
> > > the
> > > > > KIP
> > > > > > > > > > > > > > to include an outline of one or more high-level
> > > > > strategies
> > > > > > > > > > > > > > we might take, but without promising any
> particular
> > > > > > behavior
> > > > > > > > > > > > > > beyond occasionally calling SinkTask::close for
> > > > > > > post-transform
> > > > > > > > > > > > > > topic partitions. I'm hoping that this logic can
> > stay
> > > > > > > internal,
> > > > > > > > > > > > > > and by notpainting ourselves into a corner with
> the
> > > > KIP,
> > > > > we
> > > > > > > > > > > > > > give ourselves leeway to tweak it in the future
> if
> > > > > > necessary
> > > > > > > > > > > > > > without filing another KIP or introducing a
> > pluggable
> > > > > > > > interface.
> > > > > > > > > > > > >
> > > > > > > > > > > > > Thanks, that's a good idea. Given the flexibility
> of
> > > > SMTs,
> > > > > > the
> > > > > > > > > > > framework
> > > > > > > > > > > > > can't really make any assumptions around topic
> > > partitions
> > > > > > post
> > > > > > > > > > > > > transformation nor does it have any way to
> > definitively
> > > > get
> > > > > > any
> > > > > > > > > such
> > > > > > > > > > > > > information from transformations which is why the
> > idea
> > > > of a
> > > > > > > cache
> > > > > > > > > > with
> > > > > > > > > > > an
> > > > > > > > > > > > > eviction policy makes perfect sense!
> > > > > > > > > > > > >
> > > > > > > > > > > > > [1] - https://www.hyrumslaw.com/
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > Yash
> > > > > > > > > > > > >
> > > > > > > > > > > > > On Thu, Feb 9, 2023 at 9:38 PM Chris Egerton
> > > > > > > > > <chrise@aiven.io.invalid
> > > > > > > > > > >
> > > > > > > > > > > > > wrote:
> > > > > > > > > > > > >
> > > > > > > > > > > > > > Hi Yash,
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > > So it looks like with the current state of
> > affairs,
> > > > > sink
> > > > > > > > tasks
> > > > > > > > > > that
> > > > > > > > > > > > > only
> > > > > > > > > > > > > > instantiate writers in the SinkTask::open method
> > (and
> > > > > don't
> > > > > > > do
> > > > > > > > > the
> > > > > > > > > > > lazy
> > > > > > > > > > > > > > instantiation in SinkTask::put that you
> mentioned)
> > > > might
> > > > > > fail
> > > > > > > > > when
> > > > > > > > > > > used
> > > > > > > > > > > > > > with topic/partition mutating SMTs even if they
> > don't
> > > > do
> > > > > > any
> > > > > > > > > > > > asynchronous
> > > > > > > > > > > > > > processing?
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Yep, exactly 👍
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > > What do you think about retaining just the
> > existing
> > > > > > methods
> > > > > > > > > > > > > > but changing when they're called in the Connect
> > > > runtime?
> > > > > > For
> > > > > > > > > > > instance,
> > > > > > > > > > > > > > instead of calling SinkTask::open after partition
> > > > > > assignment
> > > > > > > > > post a
> > > > > > > > > > > > > > consumer group rebalance, we could cache the
> > > currently
> > > > > > "seen"
> > > > > > > > > topic
> > > > > > > > > > > > > > partitions (post transformation) and before each
> > call
> > > > to
> > > > > > > > > > > SinkTask::put
> > > > > > > > > > > > > > check whether there's any new "unseen" topic
> > > > partitions,
> > > > > > and
> > > > > > > if
> > > > > > > > > so
> > > > > > > > > > > call
> > > > > > > > > > > > > > SinkTask::open (and also update the cache of
> > course).
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > IMO the issue here is that it's a drastic change
> in
> > > > > > behavior
> > > > > > > to
> > > > > > > > > > start
> > > > > > > > > > > > > > invoking SinkTask::open and SinkTask::close with
> > > > > > > post-transform
> > > > > > > > > > topic
> > > > > > > > > > > > > > partitions instead of pre-transform, especially
> if
> > > > > > connectors
> > > > > > > > are
> > > > > > > > > > > > > > intentionally designed around original topic
> > > partitions
> > > > > > > instead
> > > > > > > > > of
> > > > > > > > > > > > > > transformed ones. I think we have to provide
> > > connector
> > > > > > > > developers
> > > > > > > > > > > with
> > > > > > > > > > > > > some
> > > > > > > > > > > > > > way to differentiate between the two, but maybe
> > > > there's a
> > > > > > way
> > > > > > > > to
> > > > > > > > > do
> > > > > > > > > > > > this
> > > > > > > > > > > > > > that I haven't thought of yet. Interested to hear
> > > your
> > > > > > > > thoughts.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Either way, I'm glad that the general idea of a
> > cache
> > > > and
> > > > > > > > > eviction
> > > > > > > > > > > > policy
> > > > > > > > > > > > > > for SinkTask::close seem reasonable; if we decide
> > to
> > > go
> > > > > > this
> > > > > > > > > route,
> > > > > > > > > > > it
> > > > > > > > > > > > > > might make sense for the KIP to include an
> outline
> > of
> > > > one
> > > > > > or
> > > > > > > > more
> > > > > > > > > > > > > > high-level strategies we might take, but without
> > > > > promising
> > > > > > > any
> > > > > > > > > > > > particular
> > > > > > > > > > > > > > behavior beyond occasionally calling
> > SinkTask::close
> > > > for
> > > > > > > > > > > post-transform
> > > > > > > > > > > > > > topic partitions. I'm hoping that this logic can
> > stay
> > > > > > > internal,
> > > > > > > > > and
> > > > > > > > > > > by
> > > > > > > > > > > > > not
> > > > > > > > > > > > > > painting ourselves into a corner with the KIP, we
> > > give
> > > > > > > > ourselves
> > > > > > > > > > > leeway
> > > > > > > > > > > > > to
> > > > > > > > > > > > > > tweak it in the future if necessary without
> filing
> > > > > another
> > > > > > > KIP
> > > > > > > > or
> > > > > > > > > > > > > > introducing a pluggable interface.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Cheers,
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Chris
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > On Thu, Feb 9, 2023 at 7:39 AM Yash Mayya <
> > > > > > > > yash.mayya@gmail.com>
> > > > > > > > > > > > wrote:
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Hi Chris,
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Thanks for the feedback.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 1) That's a fair point; while I did scan
> > everything
> > > > > > > publicly
> > > > > > > > > > > > available
> > > > > > > > > > > > > on
> > > > > > > > > > > > > > > GitHub, you're right in that it won't cover all
> > > > > possible
> > > > > > > SMTs
> > > > > > > > > > that
> > > > > > > > > > > > are
> > > > > > > > > > > > > > out
> > > > > > > > > > > > > > > there. Thanks for the example use-case as well,
> > > I've
> > > > > > > updated
> > > > > > > > > the
> > > > > > > > > > > KIP
> > > > > > > > > > > > to
> > > > > > > > > > > > > > add
> > > > > > > > > > > > > > > the two new proposed methods.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 2) So it looks like with the current state of
> > > > affairs,
> > > > > > sink
> > > > > > > > > tasks
> > > > > > > > > > > > that
> > > > > > > > > > > > > > only
> > > > > > > > > > > > > > > instantiate writers in the SinkTask::open
> method
> > > (and
> > > > > > don't
> > > > > > > > do
> > > > > > > > > > the
> > > > > > > > > > > > lazy
> > > > > > > > > > > > > > > instantiation in SinkTask::put that you
> > mentioned)
> > > > > might
> > > > > > > fail
> > > > > > > > > > when
> > > > > > > > > > > > used
> > > > > > > > > > > > > > > with topic/partition mutating SMTs even if they
> > > don't
> > > > > do
> > > > > > > any
> > > > > > > > > > > > > asynchronous
> > > > > > > > > > > > > > > processing? Since they could encounter records
> in
> > > > > > > > SinkTask::put
> > > > > > > > > > > with
> > > > > > > > > > > > > > > topics/partitions that they might not have
> > created
> > > > > > writers
> > > > > > > > for.
> > > > > > > > > > > > Thanks
> > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > pointing this out, it's definitely another
> > > > > > incompatibility
> > > > > > > > that
> > > > > > > > > > > needs
> > > > > > > > > > > > > to
> > > > > > > > > > > > > > be
> > > > > > > > > > > > > > > called out and fixed. The overloaded method
> > > approach
> > > > is
> > > > > > > > > > > interesting,
> > > > > > > > > > > > > but
> > > > > > > > > > > > > > > comes with the caveat of yet more new methods
> > that
> > > > will
> > > > > > > need
> > > > > > > > to
> > > > > > > > > > be
> > > > > > > > > > > > > > > implemented by existing connectors if they want
> > to
> > > > make
> > > > > > use
> > > > > > > > of
> > > > > > > > > > this
> > > > > > > > > > > > new
> > > > > > > > > > > > > > > functionality. What do you think about
> retaining
> > > just
> > > > > the
> > > > > > > > > > existing
> > > > > > > > > > > > > > methods
> > > > > > > > > > > > > > > but changing when they're called in the Connect
> > > > > runtime?
> > > > > > > For
> > > > > > > > > > > > instance,
> > > > > > > > > > > > > > > instead of calling SinkTask::open after
> partition
> > > > > > > assignment
> > > > > > > > > > post a
> > > > > > > > > > > > > > > consumer group rebalance, we could cache the
> > > > currently
> > > > > > > "seen"
> > > > > > > > > > topic
> > > > > > > > > > > > > > > partitions (post transformation) and before
> each
> > > call
> > > > > to
> > > > > > > > > > > > SinkTask::put
> > > > > > > > > > > > > > > check whether there's any new "unseen" topic
> > > > > partitions,
> > > > > > > and
> > > > > > > > if
> > > > > > > > > > so
> > > > > > > > > > > > call
> > > > > > > > > > > > > > > SinkTask::open (and also update the cache of
> > > > course). I
> > > > > > > don't
> > > > > > > > > > think
> > > > > > > > > > > > > this
> > > > > > > > > > > > > > > would break the existing contract with sink
> tasks
> > > > where
> > > > > > > > > > > > SinkTask::open
> > > > > > > > > > > > > is
> > > > > > > > > > > > > > > expected to be called for a topic partition
> > before
> > > > any
> > > > > > > > records
> > > > > > > > > > from
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > topic partition are sent via SinkTask::put? The
> > > > > > > > SinkTask::close
> > > > > > > > > > > case
> > > > > > > > > > > > > is a
> > > > > > > > > > > > > > > lot trickier however, and would require some
> sort
> > > of
> > > > > > cache
> > > > > > > > > > eviction
> > > > > > > > > > > > > > policy
> > > > > > > > > > > > > > > that would be deemed appropriate as you pointed
> > out
> > > > > too.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > Yash
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > On Mon, Feb 6, 2023 at 11:27 PM Chris Egerton
> > > > > > > > > > > > <chrise@aiven.io.invalid
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Hi Yash,
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > I've had some time to think on this KIP and I
> > > think
> > > > > I'm
> > > > > > > in
> > > > > > > > > > > > agreement
> > > > > > > > > > > > > > > about
> > > > > > > > > > > > > > > > not blocking it on an official compatibility
> > > > library
> > > > > or
> > > > > > > > > adding
> > > > > > > > > > > the
> > > > > > > > > > > > > > "ack"
> > > > > > > > > > > > > > > > API for sink records.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > I only have two more thoughts:
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 1. Because it is possible to manipulate sink
> > > record
> > > > > > > > > partitions
> > > > > > > > > > > and
> > > > > > > > > > > > > > > offsets
> > > > > > > > > > > > > > > > with the current API we provide for
> > > > transformations,
> > > > > I
> > > > > > > > still
> > > > > > > > > > > > believe
> > > > > > > > > > > > > > > > methods should be added to the SinkRecord
> class
> > > to
> > > > > > expose
> > > > > > > > the
> > > > > > > > > > > > > original
> > > > > > > > > > > > > > > > partition and offset, not just the original
> > > topic.
> > > > > The
> > > > > > > > > > additional
> > > > > > > > > > > > > > > cognitive
> > > > > > > > > > > > > > > > burden from these two methods is going to be
> > > > minimal
> > > > > > > > anyways;
> > > > > > > > > > > once
> > > > > > > > > > > > > > users
> > > > > > > > > > > > > > > > understand the difference between the
> > transformed
> > > > > topic
> > > > > > > > name
> > > > > > > > > > and
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > > original one, it's going to be trivial for
> them
> > > to
> > > > > > > > understand
> > > > > > > > > > how
> > > > > > > > > > > > > that
> > > > > > > > > > > > > > > same
> > > > > > > > > > > > > > > > difference applies for partitions and
> offsets.
> > > It's
> > > > > not
> > > > > > > > > enough
> > > > > > > > > > to
> > > > > > > > > > > > > scan
> > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > set of SMTs provided out of the box with
> > Connect,
> > > > > ones
> > > > > > > > > > developed
> > > > > > > > > > > by
> > > > > > > > > > > > > > > > Confluent, or even everything available on
> > > GitHub,
> > > > > > since
> > > > > > > > > there
> > > > > > > > > > > may
> > > > > > > > > > > > be
> > > > > > > > > > > > > > > > closed-source projects out there that rely on
> > > this
> > > > > > > ability.
> > > > > > > > > One
> > > > > > > > > > > > > > potential
> > > > > > > > > > > > > > > > use case could be re-routing partitions
> between
> > > > Kafka
> > > > > > and
> > > > > > > > > some
> > > > > > > > > > > > other
> > > > > > > > > > > > > > > > sharded system.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > 2. We still have to address the
> SinkTask::open
> > > [1]
> > > > > and
> > > > > > > > > > > > > SinkTask::close
> > > > > > > > > > > > > > > [2]
> > > > > > > > > > > > > > > > methods. If a connector writes to the
> external
> > > > system
> > > > > > > using
> > > > > > > > > the
> > > > > > > > > > > > > > > transformed
> > > > > > > > > > > > > > > > topic partitions it reads from Kafka, then
> it's
> > > > > > possible
> > > > > > > > for
> > > > > > > > > > the
> > > > > > > > > > > > > > > connector
> > > > > > > > > > > > > > > > to lazily instantiate writers for topic
> > > partitions
> > > > as
> > > > > > it
> > > > > > > > > > > encounters
> > > > > > > > > > > > > > them
> > > > > > > > > > > > > > > > from records provided in SinkTask::put.
> > However,
> > > > > > > connectors
> > > > > > > > > > also
> > > > > > > > > > > > > need a
> > > > > > > > > > > > > > > way
> > > > > > > > > > > > > > > > to de-allocate those writers (and the
> resources
> > > > used
> > > > > by
> > > > > > > > them)
> > > > > > > > > > > over
> > > > > > > > > > > > > > time,
> > > > > > > > > > > > > > > > which they can't do as easily. One possible
> > > > approach
> > > > > > here
> > > > > > > > is
> > > > > > > > > to
> > > > > > > > > > > > > > overload
> > > > > > > > > > > > > > > > SinkTask::open and SinkTask::close with
> > variants
> > > > that
> > > > > > > > > > distinguish
> > > > > > > > > > > > > > between
> > > > > > > > > > > > > > > > transformed and original topic partitions,
> and
> > > > > default
> > > > > > to
> > > > > > > > > > > invoking
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > existing methods with just the original topic
> > > > > > partitions.
> > > > > > > > We
> > > > > > > > > > > would
> > > > > > > > > > > > > then
> > > > > > > > > > > > > > > > have several options for how the Connect
> > runtime
> > > > can
> > > > > > > invoke
> > > > > > > > > > these
> > > > > > > > > > > > > > > methods,
> > > > > > > > > > > > > > > > but in general, an approach that guarantees
> > that
> > > > > tasks
> > > > > > > are
> > > > > > > > > > > notified
> > > > > > > > > > > > > of
> > > > > > > > > > > > > > > > transformed topic partitions in
> SinkTask::open
> > > > before
> > > > > > any
> > > > > > > > > > records
> > > > > > > > > > > > for
> > > > > > > > > > > > > > > that
> > > > > > > > > > > > > > > > partition are given to it in SinkTask::put,
> and
> > > > > makes a
> > > > > > > > > > > best-effort
> > > > > > > > > > > > > > > attempt
> > > > > > > > > > > > > > > > to close transformed topic partitions that
> > appear
> > > > to
> > > > > no
> > > > > > > > > longer
> > > > > > > > > > be
> > > > > > > > > > > > in
> > > > > > > > > > > > > > use
> > > > > > > > > > > > > > > > based on some eviction policy, would probably
> > be
> > > > > > > > sufficient.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > [1] -
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://kafka.apache.org/33/javadoc/org/apache/kafka/connect/sink/SinkTask.html#open(java.util.Collection)
> > > > > > > > > > > > > > > > [2] -
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://kafka.apache.org/33/javadoc/org/apache/kafka/connect/sink/SinkTask.html#close(java.util.Collection)
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Cheers,
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Chris
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > On Sat, Nov 5, 2022 at 5:46 AM Yash Mayya <
> > > > > > > > > > yash.mayya@gmail.com>
> > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Hi Chris,
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Thanks a lot for your inputs!
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > would provide a simple, clean interface
> for
> > > > > > > developers
> > > > > > > > to
> > > > > > > > > > > > > determine
> > > > > > > > > > > > > > > > > > which features are supported by the
> version
> > > of
> > > > > the
> > > > > > > > > Connect
> > > > > > > > > > > > > runtime
> > > > > > > > > > > > > > > > > > that their plugin has been deployed onto
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > I do like the idea of having such a public
> > > > > > > compatibility
> > > > > > > > > > > library
> > > > > > > > > > > > -
> > > > > > > > > > > > > I
> > > > > > > > > > > > > > > > think
> > > > > > > > > > > > > > > > > it would remove a lot of restrictions from
> > > > > framework
> > > > > > > > > > > development
> > > > > > > > > > > > if
> > > > > > > > > > > > > > it
> > > > > > > > > > > > > > > > were
> > > > > > > > > > > > > > > > > to be widely adopted.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > we might consider adding an API to "ack"
> > sink
> > > > > > records
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > I agree that this does seem like a more
> > > intuitive
> > > > > and
> > > > > > > > clean
> > > > > > > > > > > API,
> > > > > > > > > > > > > but
> > > > > > > > > > > > > > > I'm
> > > > > > > > > > > > > > > > > concerned about the backward compatibility
> > > > headache
> > > > > > > we'd
> > > > > > > > be
> > > > > > > > > > > > > imposing
> > > > > > > > > > > > > > on
> > > > > > > > > > > > > > > > all
> > > > > > > > > > > > > > > > > existing sink connectors. Connector
> > developers
> > > > will
> > > > > > > have
> > > > > > > > to
> > > > > > > > > > > > > maintain
> > > > > > > > > > > > > > > two
> > > > > > > > > > > > > > > > > separate ways of doing offset management if
> > > they
> > > > > want
> > > > > > > to
> > > > > > > > > use
> > > > > > > > > > > the
> > > > > > > > > > > > > new
> > > > > > > > > > > > > > > API
> > > > > > > > > > > > > > > > > but continue supporting older versions of
> > Kafka
> > > > > > > Connect.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > For now, I've reverted the KIP to the
> > previous
> > > > > > > iteration
> > > > > > > > > > which
> > > > > > > > > > > > > > proposed
> > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > addition of a new `SinkRecord` method to
> > obtain
> > > > the
> > > > > > > > > original
> > > > > > > > > > > > Kafka
> > > > > > > > > > > > > > > topic
> > > > > > > > > > > > > > > > > pre-transformation. One thing to note is
> that
> > > > I've
> > > > > > > > removed
> > > > > > > > > > the
> > > > > > > > > > > > > method
> > > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > > obtaining the original Kafka partition
> after
> > a
> > > > > > cursory
> > > > > > > > > search
> > > > > > > > > > > > > showed
> > > > > > > > > > > > > > > that
> > > > > > > > > > > > > > > > > use cases for partition modifying SMTs are
> > > > > primarily
> > > > > > on
> > > > > > > > the
> > > > > > > > > > > > source
> > > > > > > > > > > > > > > > > connector side.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > > Yash
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > On Tue, Nov 1, 2022 at 9:22 PM Chris
> Egerton
> > > > > > > > > > > > > <chrise@aiven.io.invalid
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > Hi all,
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > I have more comments I'd like to make on
> > this
> > > > KIP
> > > > > > > when
> > > > > > > > I
> > > > > > > > > > have
> > > > > > > > > > > > > time
> > > > > > > > > > > > > > > > (sorry
> > > > > > > > > > > > > > > > > > for the delay, Yash, and thanks for your
> > > > > > patience!),
> > > > > > > > but
> > > > > > > > > I
> > > > > > > > > > > did
> > > > > > > > > > > > > want
> > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > chime in and say that I'm also not sure
> > about
> > > > > > > > overloading
> > > > > > > > > > > > > > > > SinkTask::put.
> > > > > > > > > > > > > > > > > I
> > > > > > > > > > > > > > > > > > share the concerns about creating an
> > > intuitive,
> > > > > > > simple
> > > > > > > > > API
> > > > > > > > > > > that
> > > > > > > > > > > > > > Yash
> > > > > > > > > > > > > > > > has
> > > > > > > > > > > > > > > > > > raised. In addition, this approach
> doesn't
> > > seem
> > > > > > very
> > > > > > > > > > > > > > > sustainable--what
> > > > > > > > > > > > > > > > do
> > > > > > > > > > > > > > > > > > we do if we encounter another case in the
> > > > future
> > > > > > that
> > > > > > > > > would
> > > > > > > > > > > > > > warrant a
> > > > > > > > > > > > > > > > > > similar solution? We probably don't want
> to
> > > > > create
> > > > > > > > three,
> > > > > > > > > > > four,
> > > > > > > > > > > > > > etc.
> > > > > > > > > > > > > > > > > > overloaded variants of the method, each
> of
> > > > which
> > > > > > > would
> > > > > > > > > have
> > > > > > > > > > > to
> > > > > > > > > > > > be
> > > > > > > > > > > > > > > > > > implemented by connector developers who
> > want
> > > to
> > > > > > both
> > > > > > > > > > leverage
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > > latest
> > > > > > > > > > > > > > > > > > and greatest connector APIs and maintain
> > > > > > > compatibility
> > > > > > > > > with
> > > > > > > > > > > > > connect
> > > > > > > > > > > > > > > > > > Clusters running older versions.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > I haven't been able to flesh this out
> into
> > a
> > > > > design
> > > > > > > > worth
> > > > > > > > > > > > > > publishing
> > > > > > > > > > > > > > > in
> > > > > > > > > > > > > > > > > its
> > > > > > > > > > > > > > > > > > own KIP yet, but one alternative I've
> > pitched
> > > > to
> > > > > a
> > > > > > > few
> > > > > > > > > > people
> > > > > > > > > > > > > with
> > > > > > > > > > > > > > > > > > generally positive interest has been to
> > > develop
> > > > > an
> > > > > > > > > official
> > > > > > > > > > > > > > > > compatibility
> > > > > > > > > > > > > > > > > > library for Connect developers. This
> > library
> > > > > would
> > > > > > be
> > > > > > > > > > > released
> > > > > > > > > > > > as
> > > > > > > > > > > > > > its
> > > > > > > > > > > > > > > > own
> > > > > > > > > > > > > > > > > > Maven artifact (separate from
> connect-api,
> > > > > > > > > connect-runtime,
> > > > > > > > > > > > etc.)
> > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > would
> > > > > > > > > > > > > > > > > > provide a simple, clean interface for
> > > > developers
> > > > > to
> > > > > > > > > > determine
> > > > > > > > > > > > > which
> > > > > > > > > > > > > > > > > > features are supported by the version of
> > the
> > > > > > Connect
> > > > > > > > > > runtime
> > > > > > > > > > > > that
> > > > > > > > > > > > > > > their
> > > > > > > > > > > > > > > > > > plugin has been deployed onto. Under the
> > > hood,
> > > > > this
> > > > > > > > > library
> > > > > > > > > > > > might
> > > > > > > > > > > > > > use
> > > > > > > > > > > > > > > > > > reflection to determine whether classes,
> > > > methods,
> > > > > > > etc.
> > > > > > > > > are
> > > > > > > > > > > > > > available,
> > > > > > > > > > > > > > > > but
> > > > > > > > > > > > > > > > > > the developer wouldn't have to do
> anything
> > > more
> > > > > > than
> > > > > > > > > check
> > > > > > > > > > > (for
> > > > > > > > > > > > > > > > example)
> > > > > > > > > > > > > > > > > >
> > > > > > `Features.SINK_TASK_ERRANT_RECORD_REPORTER.enabled()`
> > > > > > > > to
> > > > > > > > > > know
> > > > > > > > > > > > at
> > > > > > > > > > > > > > any
> > > > > > > > > > > > > > > > > point
> > > > > > > > > > > > > > > > > > in the lifetime of their connector/task
> > > whether
> > > > > > that
> > > > > > > > > > feature
> > > > > > > > > > > is
> > > > > > > > > > > > > > > > provided
> > > > > > > > > > > > > > > > > by
> > > > > > > > > > > > > > > > > > the runtime.
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > One other high-level comment: this
> doesn't
> > > > > address
> > > > > > > > every
> > > > > > > > > > > case,
> > > > > > > > > > > > > but
> > > > > > > > > > > > > > we
> > > > > > > > > > > > > > > > > might
> > > > > > > > > > > > > > > > > > consider adding an API to "ack" sink
> > records.
> > > > > This
> > > > > > > > could
> > > > > > > > > > use
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > SubmittedRecords class [1] (with some
> > slight
> > > > > > tweaks)
> > > > > > > > > under
> > > > > > > > > > > the
> > > > > > > > > > > > > hood
> > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > track the latest-acked offset for each
> > topic
> > > > > > > partition.
> > > > > > > > > > This
> > > > > > > > > > > > way,
> > > > > > > > > > > > > > > > > connector
> > > > > > > > > > > > > > > > > > developers won't be responsible for
> > tracking
> > > > > > offsets
> > > > > > > at
> > > > > > > > > all
> > > > > > > > > > > in
> > > > > > > > > > > > > > their
> > > > > > > > > > > > > > > > sink
> > > > > > > > > > > > > > > > > > tasks (eliminating issues with the
> accuracy
> > > of
> > > > > > > > > > > > > post-transformation
> > > > > > > > > > > > > > > > T/P/O
> > > > > > > > > > > > > > > > > > sink record information), and they'll
> only
> > > have
> > > > > to
> > > > > > > > notify
> > > > > > > > > > the
> > > > > > > > > > > > > > Connect
> > > > > > > > > > > > > > > > > > framework when a record has been
> > successfully
> > > > > > > > dispatched
> > > > > > > > > to
> > > > > > > > > > > the
> > > > > > > > > > > > > > > > external
> > > > > > > > > > > > > > > > > > system. This provides a cleaner,
> friendlier
> > > > API,
> > > > > > and
> > > > > > > > also
> > > > > > > > > > > > enables
> > > > > > > > > > > > > > > more
> > > > > > > > > > > > > > > > > > fine-grained metrics like the ones
> proposed
> > > in
> > > > > > > KIP-767
> > > > > > > > > [2].
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > [1] -
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://github.com/apache/kafka/blob/9ab140d5419d735baae45aff56ffce7f5622744f/connect/runtime/src/main/java/org/apache/kafka/connect/runtime/SubmittedRecords.java
> > > > > > > > > > > > > > > > > > [2] -
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-767%3A+Connect+Latency+Metrics
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > Cheers,
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > Chris
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > On Tue, Nov 1, 2022 at 11:21 AM Yash
> Mayya
> > <
> > > > > > > > > > > > yash.mayya@gmail.com
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Hi Randall,
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > It's been a while for this one but the
> > > more I
> > > > > > think
> > > > > > > > > about
> > > > > > > > > > > it,
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > more
> > > > > > > > > > > > > > > > > I
> > > > > > > > > > > > > > > > > > > feel like the current approach with a
> new
> > > > > > > overloaded
> > > > > > > > > > > > > > > `SinkTask::put`
> > > > > > > > > > > > > > > > > > method
> > > > > > > > > > > > > > > > > > > might not be optimal. We're trying to
> > fix a
> > > > > > pretty
> > > > > > > > > corner
> > > > > > > > > > > > case
> > > > > > > > > > > > > > bug
> > > > > > > > > > > > > > > > here
> > > > > > > > > > > > > > > > > > > (usage of topic mutating SMTs with sink
> > > > > > connectors
> > > > > > > > that
> > > > > > > > > > do
> > > > > > > > > > > > > their
> > > > > > > > > > > > > > > own
> > > > > > > > > > > > > > > > > > offset
> > > > > > > > > > > > > > > > > > > tracking) and I'm not sure that
> warrants
> > a
> > > > > change
> > > > > > > to
> > > > > > > > > > such a
> > > > > > > > > > > > > > central
> > > > > > > > > > > > > > > > > > > interface method. The new
> `SinkTask::put`
> > > > > method
> > > > > > > just
> > > > > > > > > > seems
> > > > > > > > > > > > > > > somewhat
> > > > > > > > > > > > > > > > > odd
> > > > > > > > > > > > > > > > > > > and it may not be very understandable
> > for a
> > > > new
> > > > > > > > reader
> > > > > > > > > -
> > > > > > > > > > I
> > > > > > > > > > > > > don't
> > > > > > > > > > > > > > > > think
> > > > > > > > > > > > > > > > > > this
> > > > > > > > > > > > > > > > > > > should be the case for a public
> interface
> > > > > method.
> > > > > > > > > > > > Furthermore,
> > > > > > > > > > > > > > even
> > > > > > > > > > > > > > > > > with
> > > > > > > > > > > > > > > > > > > elaborate documentation in place, I'm
> not
> > > > sure
> > > > > if
> > > > > > > > it'll
> > > > > > > > > > be
> > > > > > > > > > > > very
> > > > > > > > > > > > > > > > obvious
> > > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > > most people what the purpose of having
> > > these
> > > > > two
> > > > > > > > `put`
> > > > > > > > > > > > methods
> > > > > > > > > > > > > is
> > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > how
> > > > > > > > > > > > > > > > > > > they should be used by sink task
> > > > > implementations.
> > > > > > > > What
> > > > > > > > > do
> > > > > > > > > > > you
> > > > > > > > > > > > > > > think?
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > > > > Yash
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > On Mon, Oct 10, 2022 at 9:33 PM Yash
> > Mayya
> > > <
> > > > > > > > > > > > > yash.mayya@gmail.com
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > Hi Randall,
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > Thanks a lot for your valuable
> feedback
> > > so
> > > > > far!
> > > > > > > > I've
> > > > > > > > > > > > updated
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > KIP
> > > > > > > > > > > > > > > > > > > based
> > > > > > > > > > > > > > > > > > > > on our discussion above. Could you
> > please
> > > > > take
> > > > > > > > > another
> > > > > > > > > > > > look?
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > > > > > Yash
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > > On Tue, Oct 4, 2022 at 12:40 AM
> Randall
> > > > > Hauch <
> > > > > > > > > > > > > > rhauch@gmail.com>
> > > > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >> On Mon, Oct 3, 2022 at 11:45 AM Yash
> > > > Mayya <
> > > > > > > > > > > > > > > yash.mayya@gmail.com>
> > > > > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >> > Hi Randall,
> > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > >> > Thanks for elaborating. I think
> > these
> > > > are
> > > > > > all
> > > > > > > > very
> > > > > > > > > > > good
> > > > > > > > > > > > > > points
> > > > > > > > > > > > > > > > > and I
> > > > > > > > > > > > > > > > > > > see
> > > > > > > > > > > > > > > > > > > >> > why the overloaded `SinkTask::put`
> > > > method
> > > > > > is a
> > > > > > > > > > cleaner
> > > > > > > > > > > > > > > solution
> > > > > > > > > > > > > > > > > > > overall.
> > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > >> > > public void
> > > put(Collection<SinkRecord>
> > > > > > > > records,
> > > > > > > > > > > > > > > > Map<SinkRecord,
> > > > > > > > > > > > > > > > > > > >> > TopicPartition>
> > > updatedTopicPartitions)
> > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > >> > I think this should be
> > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > >> > `public void
> > > put(Collection<SinkRecord>
> > > > > > > records,
> > > > > > > > > > > > > > > Map<SinkRecord,
> > > > > > > > > > > > > > > > > > > >> > TopicPartition>
> > > > originalTopicPartitions)`
> > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > >> > instead because the sink records
> > > > > themselves
> > > > > > > have
> > > > > > > > > the
> > > > > > > > > > > > > updated
> > > > > > > > > > > > > > > > topic
> > > > > > > > > > > > > > > > > > > >> > partitions (i.e. after all
> > > > transformations
> > > > > > > have
> > > > > > > > > been
> > > > > > > > > > > > > > applied)
> > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > >> KIP
> > > > > > > > > > > > > > > > > > > >> > is proposing a way for the tasks
> to
> > be
> > > > > able
> > > > > > to
> > > > > > > > > > access
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > > original
> > > > > > > > > > > > > > > > > > > topic
> > > > > > > > > > > > > > > > > > > >> > partition (i.e. before
> > transformations
> > > > > have
> > > > > > > been
> > > > > > > > > > > > applied).
> > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >> Sounds good.
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > >> > > Of course, if the developer does
> > not
> > > > > need
> > > > > > > > > separate
> > > > > > > > > > > > > > methods,
> > > > > > > > > > > > > > > > they
> > > > > > > > > > > > > > > > > > can
> > > > > > > > > > > > > > > > > > > >> > easily have the older `put` method
> > > > simply
> > > > > > > > delegate
> > > > > > > > > > to
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > newer
> > > > > > > > > > > > > > > > > > > method.
> > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > >> > If the developer does not need
> > > separate
> > > > > > > methods
> > > > > > > > > > (i.e.
> > > > > > > > > > > > they
> > > > > > > > > > > > > > > don't
> > > > > > > > > > > > > > > > > > need
> > > > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > > >> > use this new addition), they can
> > > simply
> > > > > > > continue
> > > > > > > > > > > > > > implementing
> > > > > > > > > > > > > > > > just
> > > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > >> > older `put` method right?
> > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >> Correct. We should update the
> JavaDoc
> > of
> > > > > both
> > > > > > > > > methods
> > > > > > > > > > to
> > > > > > > > > > > > > make
> > > > > > > > > > > > > > > this
> > > > > > > > > > > > > > > > > > > clear,
> > > > > > > > > > > > > > > > > > > >> and in general how the two methods
> > > should
> > > > > are
> > > > > > > used
> > > > > > > > > and
> > > > > > > > > > > > > should
> > > > > > > > > > > > > > be
> > > > > > > > > > > > > > > > > > > >> implemented. That can be part of the
> > PR,
> > > > and
> > > > > > the
> > > > > > > > KIP
> > > > > > > > > > > > doesn't
> > > > > > > > > > > > > > > need
> > > > > > > > > > > > > > > > > this
> > > > > > > > > > > > > > > > > > > >> wording.
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > >> > > Finally, this gives us a roadmap
> > for
> > > > > > > > > *eventually*
> > > > > > > > > > > > > > > deprecating
> > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > >> older
> > > > > > > > > > > > > > > > > > > >> > method, once the Connect runtime
> > > > versions
> > > > > > > > without
> > > > > > > > > > this
> > > > > > > > > > > > > > change
> > > > > > > > > > > > > > > > are
> > > > > > > > > > > > > > > > > > old
> > > > > > > > > > > > > > > > > > > >> > enough.
> > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > >> > I'm not sure we'd ever want to
> > > deprecate
> > > > > the
> > > > > > > > older
> > > > > > > > > > > > method.
> > > > > > > > > > > > > > > Most
> > > > > > > > > > > > > > > > > > common
> > > > > > > > > > > > > > > > > > > >> sink
> > > > > > > > > > > > > > > > > > > >> > connector implementations do not
> do
> > > > their
> > > > > > own
> > > > > > > > > offset
> > > > > > > > > > > > > > tracking
> > > > > > > > > > > > > > > > with
> > > > > > > > > > > > > > > > > > > >> > asynchronous processing and will
> > > > probably
> > > > > > > never
> > > > > > > > > > have a
> > > > > > > > > > > > > need
> > > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > >> > additional parameter
> > `Map<SinkRecord,
> > > > > > > > > > TopicPartition>
> > > > > > > > > > > > > > > > > > > >> > originalTopicPartitions` in the
> > > proposed
> > > > > new
> > > > > > > > `put`
> > > > > > > > > > > > method.
> > > > > > > > > > > > > > > These
> > > > > > > > > > > > > > > > > > > >> connectors
> > > > > > > > > > > > > > > > > > > >> > can continue implementing only the
> > > > > existing
> > > > > > > > > > > > > `SinkTask::put`
> > > > > > > > > > > > > > > > method
> > > > > > > > > > > > > > > > > > > which
> > > > > > > > > > > > > > > > > > > >> > will be called by the default
> > > > > implementation
> > > > > > > of
> > > > > > > > > the
> > > > > > > > > > > > newer
> > > > > > > > > > > > > > > > > overloaded
> > > > > > > > > > > > > > > > > > > >> `put`
> > > > > > > > > > > > > > > > > > > >> > method.
> > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >> +1
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > >> > > the pre-commit methods use the
> > same
> > > > > > > > > > > > `Map<TopicPartition,
> > > > > > > > > > > > > > > > > > > >> > OffsetAndMetadata> currentOffsets`
> > > data
> > > > > > > > structure
> > > > > > > > > > I'm
> > > > > > > > > > > > > > > suggesting
> > > > > > > > > > > > > > > > > be
> > > > > > > > > > > > > > > > > > > >> used.
> > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > >> > The data structure you're
> suggesting
> > > be
> > > > > used
> > > > > > > is
> > > > > > > > a
> > > > > > > > > > > > > > > > `Map<SinkRecord,
> > > > > > > > > > > > > > > > > > > >> > TopicPartition>` which will map
> > > > > `SinkRecord`
> > > > > > > > > objects
> > > > > > > > > > > to
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > original
> > > > > > > > > > > > > > > > > > > >> topic
> > > > > > > > > > > > > > > > > > > >> > partition of the corresponding
> > > > > > > `ConsumerRecord`
> > > > > > > > > > right?
> > > > > > > > > > > > To
> > > > > > > > > > > > > > > > clarify,
> > > > > > > > > > > > > > > > > > > this
> > > > > > > > > > > > > > > > > > > >> is
> > > > > > > > > > > > > > > > > > > >> > a new data structure that will
> need
> > to
> > > > be
> > > > > > > > managed
> > > > > > > > > in
> > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > >> `WorkerSinkTask`.
> > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >> Ah, you're right. Thanks for the
> > > > correction.
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >> Best regards,
> > > > > > > > > > > > > > > > > > > >> Randall
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >> > Thanks,
> > > > > > > > > > > > > > > > > > > >> > Yash
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >> > On Mon, Oct 3, 2022 at 1:20 AM
> > Randall
> > > > > > Hauch <
> > > > > > > > > > > > > > > rhauch@gmail.com>
> > > > > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > >> > > Hi, Yash.
> > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > >> > > I'm not sure I quite understand
> > why
> > > it
> > > > > > would
> > > > > > > > be
> > > > > > > > > > > > "easier"
> > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > > > > connector
> > > > > > > > > > > > > > > > > > > >> > > > developers to account for
> > > > implementing
> > > > > > two
> > > > > > > > > > > different
> > > > > > > > > > > > > > > > > overloaded
> > > > > > > > > > > > > > > > > > > >> `put`
> > > > > > > > > > > > > > > > > > > >> > > > methods (assuming that they
> want
> > > to
> > > > > use
> > > > > > > this
> > > > > > > > > new
> > > > > > > > > > > > > > feature)
> > > > > > > > > > > > > > > > > versus
> > > > > > > > > > > > > > > > > > > >> using
> > > > > > > > > > > > > > > > > > > >> > a
> > > > > > > > > > > > > > > > > > > >> > > > try-catch block around
> > > `SinkRecord`
> > > > > > access
> > > > > > > > > > > methods?
> > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > >> > > Using a try-catch to try around
> an
> > > API
> > > > > > > method
> > > > > > > > > that
> > > > > > > > > > > > > *might*
> > > > > > > > > > > > > > > be
> > > > > > > > > > > > > > > > > > there
> > > > > > > > > > > > > > > > > > > >> is a
> > > > > > > > > > > > > > > > > > > >> > > very unusual thing for most
> > > > developers.
> > > > > > > > > > > Unfortunately,
> > > > > > > > > > > > > > we've
> > > > > > > > > > > > > > > > had
> > > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > > >> > resort
> > > > > > > > > > > > > > > > > > > >> > > to this atypical approach with
> > > Connect
> > > > > in
> > > > > > > > places
> > > > > > > > > > > when
> > > > > > > > > > > > > > there
> > > > > > > > > > > > > > > > was
> > > > > > > > > > > > > > > > > no
> > > > > > > > > > > > > > > > > > > >> good
> > > > > > > > > > > > > > > > > > > >> > > alternative. We seem to relying
> > upon
> > > > > > pattern
> > > > > > > > > > because
> > > > > > > > > > > > > it's
> > > > > > > > > > > > > > > > easier
> > > > > > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > > > > >> us,
> > > > > > > > > > > > > > > > > > > >> > > not because it offers a better
> > > > > experience
> > > > > > > for
> > > > > > > > > > > > Connector
> > > > > > > > > > > > > > > > > > developers.
> > > > > > > > > > > > > > > > > > > >> IMO,
> > > > > > > > > > > > > > > > > > > >> > if
> > > > > > > > > > > > > > > > > > > >> > > there's a practical alternative
> > that
> > > > > uses
> > > > > > > > normal
> > > > > > > > > > > > > > development
> > > > > > > > > > > > > > > > > > > practices
> > > > > > > > > > > > > > > > > > > >> > and
> > > > > > > > > > > > > > > > > > > >> > > techniques, then we should use
> > that
> > > > > > > > alternative.
> > > > > > > > > > > IIUC,
> > > > > > > > > > > > > > there
> > > > > > > > > > > > > > > > is
> > > > > > > > > > > > > > > > > at
> > > > > > > > > > > > > > > > > > > >> least
> > > > > > > > > > > > > > > > > > > >> > > one practical alternative for
> this
> > > KIP
> > > > > > that
> > > > > > > > > would
> > > > > > > > > > > not
> > > > > > > > > > > > > > > require
> > > > > > > > > > > > > > > > > > > >> developers
> > > > > > > > > > > > > > > > > > > >> > to
> > > > > > > > > > > > > > > > > > > >> > > use the unusual try-catch to
> > handle
> > > > the
> > > > > > case
> > > > > > > > > where
> > > > > > > > > > > > > methods
> > > > > > > > > > > > > > > are
> > > > > > > > > > > > > > > > > not
> > > > > > > > > > > > > > > > > > > >> found.
> > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > >> > > I also think having two `put`
> > > methods
> > > > is
> > > > > > > > easier
> > > > > > > > > > when
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > Connector
> > > > > > > > > > > > > > > > > > > >> has to
> > > > > > > > > > > > > > > > > > > >> > > do different things for
> different
> > > > > Connect
> > > > > > > > > > runtimes,
> > > > > > > > > > > > too.
> > > > > > > > > > > > > > One
> > > > > > > > > > > > > > > > of
> > > > > > > > > > > > > > > > > > > those
> > > > > > > > > > > > > > > > > > > >> > > methods is called by newer
> Connect
> > > > > > runtimes
> > > > > > > > with
> > > > > > > > > > the
> > > > > > > > > > > > new
> > > > > > > > > > > > > > > > > behavior,
> > > > > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > >> > the
> > > > > > > > > > > > > > > > > > > >> > > other method is called by an
> older
> > > > > Connect
> > > > > > > > > > runtime.
> > > > > > > > > > > Of
> > > > > > > > > > > > > > > course,
> > > > > > > > > > > > > > > > > if
> > > > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > >> > > developer does not need separate
> > > > > methods,
> > > > > > > they
> > > > > > > > > can
> > > > > > > > > > > > > easily
> > > > > > > > > > > > > > > have
> > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > >> older
> > > > > > > > > > > > > > > > > > > >> > > `put` method simply delegate to
> > the
> > > > > newer
> > > > > > > > > method.
> > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > >> > > Finally, this gives us a roadmap
> > for
> > > > > > > > > *eventually*
> > > > > > > > > > > > > > > deprecating
> > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > >> older
> > > > > > > > > > > > > > > > > > > >> > > method, once the Connect runtime
> > > > > versions
> > > > > > > > > without
> > > > > > > > > > > this
> > > > > > > > > > > > > > > change
> > > > > > > > > > > > > > > > > are
> > > > > > > > > > > > > > > > > > > old
> > > > > > > > > > > > > > > > > > > >> > > enough.
> > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > >> > > I think the advantage of going
> > with
> > > > the
> > > > > > > > > > > > > > > > > > > >> > > > proposed approach in the KIP
> is
> > > that
> > > > > it
> > > > > > > > > wouldn't
> > > > > > > > > > > > > require
> > > > > > > > > > > > > > > > extra
> > > > > > > > > > > > > > > > > > > >> > > book-keeping
> > > > > > > > > > > > > > > > > > > >> > > > (the Map<SinkRecord,
> > > > > > > > > > > > > > > > > > > >> > > > TopicPartition> in
> > > `WorkerSinkTask`
> > > > in
> > > > > > > your
> > > > > > > > > > > proposed
> > > > > > > > > > > > > > > > approach)
> > > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > >> > > The connector does have to do
> some
> > > of
> > > > > this
> > > > > > > > > > > bookkeeping
> > > > > > > > > > > > > in
> > > > > > > > > > > > > > > how
> > > > > > > > > > > > > > > > > they
> > > > > > > > > > > > > > > > > > > >> track
> > > > > > > > > > > > > > > > > > > >> > > the topic partition offsets used
> > in
> > > > the
> > > > > > > > > > `preCommit`,
> > > > > > > > > > > > and
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > >> pre-commit
> > > > > > > > > > > > > > > > > > > >> > > methods use the same
> > > > > `Map<TopicPartition,
> > > > > > > > > > > > > > OffsetAndMetadata>
> > > > > > > > > > > > > > > > > > > >> > > currentOffsets`
> > > > > > > > > > > > > > > > > > > >> > > data structure I'm suggesting be
> > > used.
> > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > >> > > I hope that helps.
> > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > >> > > Best regards,
> > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > >> > > Randall
> > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > >> > > On Mon, Sep 26, 2022 at 9:38 AM
> > Yash
> > > > > > Mayya <
> > > > > > > > > > > > > > > > > yash.mayya@gmail.com>
> > > > > > > > > > > > > > > > > > > >> wrote:
> > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > >> > > > Hi Randall,
> > > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > > >> > > > Thanks for reviewing the KIP!
> > > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > > >> > > > > That latter logic can get
> > quite
> > > > > ugly.
> > > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > > >> > > > I'm not sure I quite
> understand
> > > why
> > > > it
> > > > > > > would
> > > > > > > > > be
> > > > > > > > > > > > > "easier"
> > > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > > > > >> connector
> > > > > > > > > > > > > > > > > > > >> > > > developers to account for
> > > > implementing
> > > > > > two
> > > > > > > > > > > different
> > > > > > > > > > > > > > > > > overloaded
> > > > > > > > > > > > > > > > > > > >> `put`
> > > > > > > > > > > > > > > > > > > >> > > > methods (assuming that they
> want
> > > to
> > > > > use
> > > > > > > this
> > > > > > > > > new
> > > > > > > > > > > > > > feature)
> > > > > > > > > > > > > > > > > versus
> > > > > > > > > > > > > > > > > > > >> using
> > > > > > > > > > > > > > > > > > > >> > a
> > > > > > > > > > > > > > > > > > > >> > > > try-catch block around
> > > `SinkRecord`
> > > > > > access
> > > > > > > > > > > methods?
> > > > > > > > > > > > In
> > > > > > > > > > > > > > > both
> > > > > > > > > > > > > > > > > > > cases, a
> > > > > > > > > > > > > > > > > > > >> > > > connector developer would need
> > to
> > > > > write
> > > > > > > > > > additional
> > > > > > > > > > > > > code
> > > > > > > > > > > > > > in
> > > > > > > > > > > > > > > > > order
> > > > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > > >> > > ensure
> > > > > > > > > > > > > > > > > > > >> > > > that their connector continues
> > > > working
> > > > > > > with
> > > > > > > > > > older
> > > > > > > > > > > > > > Connect
> > > > > > > > > > > > > > > > > > > runtimes.
> > > > > > > > > > > > > > > > > > > >> > > > Furthermore, we would probably
> > > need
> > > > to
> > > > > > > > > carefully
> > > > > > > > > > > > > > document
> > > > > > > > > > > > > > > > how
> > > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > > >> > > > implementation for the older
> > `put`
> > > > > > method
> > > > > > > > > should
> > > > > > > > > > > > look
> > > > > > > > > > > > > > like
> > > > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > > > > >> > connectors
> > > > > > > > > > > > > > > > > > > >> > > > that want to use this new
> > > feature. I
> > > > > > think
> > > > > > > > the
> > > > > > > > > > > > > advantage
> > > > > > > > > > > > > > > of
> > > > > > > > > > > > > > > > > > going
> > > > > > > > > > > > > > > > > > > >> with
> > > > > > > > > > > > > > > > > > > >> > > the
> > > > > > > > > > > > > > > > > > > >> > > > proposed approach in the KIP
> is
> > > that
> > > > > it
> > > > > > > > > wouldn't
> > > > > > > > > > > > > require
> > > > > > > > > > > > > > > > extra
> > > > > > > > > > > > > > > > > > > >> > > book-keeping
> > > > > > > > > > > > > > > > > > > >> > > > (the Map<SinkRecord,
> > > > > > > > > > > > > > > > > > > >> > > > TopicPartition> in
> > > `WorkerSinkTask`
> > > > in
> > > > > > > your
> > > > > > > > > > > proposed
> > > > > > > > > > > > > > > > approach)
> > > > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > >> also
> > > > > > > > > > > > > > > > > > > >> > > the
> > > > > > > > > > > > > > > > > > > >> > > > fact that the try-catch based
> > > logic
> > > > is
> > > > > > an
> > > > > > > > > > already
> > > > > > > > > > > > > > > > established
> > > > > > > > > > > > > > > > > > > >> pattern
> > > > > > > > > > > > > > > > > > > >> > > > through
> > > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-610%3A+Error+Reporting+in+Sink+Connectors
> > > > > > > > > > > > > > > > > > > >> > > > and other KIPs which added
> > methods
> > > > to
> > > > > > > > > > source/sink
> > > > > > > > > > > > > > > > > connector/task
> > > > > > > > > > > > > > > > > > > >> > > contexts.
> > > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > > >> > > > Let me know if you still feel
> > that
> > > > > > having
> > > > > > > a
> > > > > > > > > new
> > > > > > > > > > > > > > overloaded
> > > > > > > > > > > > > > > > put
> > > > > > > > > > > > > > > > > > > >> method
> > > > > > > > > > > > > > > > > > > >> > is
> > > > > > > > > > > > > > > > > > > >> > > a
> > > > > > > > > > > > > > > > > > > >> > > > cleaner solution and I'd be
> > happy
> > > to
> > > > > > > > > reconsider!
> > > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > > >> > > > Thanks,
> > > > > > > > > > > > > > > > > > > >> > > > Yash
> > > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > > >> > > > On Thu, Sep 22, 2022 at 11:18
> PM
> > > > > Randall
> > > > > > > > > Hauch <
> > > > > > > > > > > > > > > > > > rhauch@gmail.com>
> > > > > > > > > > > > > > > > > > > >> > wrote:
> > > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > > >> > > > > Hi, Yash. Thanks for picking
> > up
> > > > this
> > > > > > KIP
> > > > > > > > and
> > > > > > > > > > > > > > discussion.
> > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > >> > > > > The KIP includes this
> rejected
> > > > > > > > alternative:
> > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > >> > > > > > 4. Update SinkTask.put in
> > any
> > > > way
> > > > > to
> > > > > > > > pass
> > > > > > > > > > the
> > > > > > > > > > > > new
> > > > > > > > > > > > > > > > > > information
> > > > > > > > > > > > > > > > > > > >> > outside
> > > > > > > > > > > > > > > > > > > >> > > > > > SinkRecord (e.g. a Map or
> a
> > > > > derived
> > > > > > > > class)
> > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > >> > > > > >    -
> > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > >> > > > > >    Much more disruptive
> > change
> > > > > > without
> > > > > > > > > > > > > considerable
> > > > > > > > > > > > > > > pros
> > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > >> > > > > One advantage about doing
> this
> > > is
> > > > > that
> > > > > > > > sink
> > > > > > > > > > > > > connector
> > > > > > > > > > > > > > > > > > > >> implementations
> > > > > > > > > > > > > > > > > > > >> > > can
> > > > > > > > > > > > > > > > > > > >> > > > > more easily implement two
> > > > different
> > > > > > > > > "put(...)"
> > > > > > > > > > > > > methods
> > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > handle
> > > > > > > > > > > > > > > > > > > >> > > running
> > > > > > > > > > > > > > > > > > > >> > > > in
> > > > > > > > > > > > > > > > > > > >> > > > > a variety of runtimes,
> without
> > > > > having
> > > > > > to
> > > > > > > > use
> > > > > > > > > > > > > try-catch
> > > > > > > > > > > > > > > > logic
> > > > > > > > > > > > > > > > > > > >> around
> > > > > > > > > > > > > > > > > > > >> > the
> > > > > > > > > > > > > > > > > > > >> > > > > newer SinkRecord access
> > methods.
> > > > > That
> > > > > > > > latter
> > > > > > > > > > > logic
> > > > > > > > > > > > > can
> > > > > > > > > > > > > > > get
> > > > > > > > > > > > > > > > > > quite
> > > > > > > > > > > > > > > > > > > >> > ugly.
> > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > >> > > > > For example, the existing
> > `put`
> > > > > method
> > > > > > > has
> > > > > > > > > > this
> > > > > > > > > > > > > > > signature:
> > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > >> > > > > public abstract void
> > > > > > > > > > put(Collection<SinkRecord>
> > > > > > > > > > > > > > > records);
> > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > >> > > > > If we added an overloaded
> > method
> > > > > that
> > > > > > > > passed
> > > > > > > > > > in
> > > > > > > > > > > a
> > > > > > > > > > > > > map
> > > > > > > > > > > > > > of
> > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > old
> > > > > > > > > > > > > > > > > > > >> > > > > topic+partition for each
> > record
> > > > (and
> > > > > > > > defined
> > > > > > > > > > the
> > > > > > > > > > > > > > absence
> > > > > > > > > > > > > > > > of
> > > > > > > > > > > > > > > > > an
> > > > > > > > > > > > > > > > > > > >> entry
> > > > > > > > > > > > > > > > > > > >> > as
> > > > > > > > > > > > > > > > > > > >> > > > > having an unchanged topic
> and
> > > > > > > partition):
> > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > >> > > > > public void
> > > > > put(Collection<SinkRecord>
> > > > > > > > > > records,
> > > > > > > > > > > > > > > > > > Map<SinkRecord,
> > > > > > > > > > > > > > > > > > > >> > > > > TopicPartition>
> > > > > > updatedTopicPartitions)
> > > > > > > {
> > > > > > > > > > > > > > > > > > > >> > > > > put(records);
> > > > > > > > > > > > > > > > > > > >> > > > > }
> > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > >> > > > > then a `SinkTask`
> > implementation
> > > > > that
> > > > > > > > wants
> > > > > > > > > to
> > > > > > > > > > > use
> > > > > > > > > > > > > > this
> > > > > > > > > > > > > > > > new
> > > > > > > > > > > > > > > > > > > >> feature
> > > > > > > > > > > > > > > > > > > >> > > could
> > > > > > > > > > > > > > > > > > > >> > > > > simply implement both
> methods:
> > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > >> > > > > public void
> > > > > put(Collection<SinkRecord>
> > > > > > > > > > records)
> > > > > > > > > > > {
> > > > > > > > > > > > > > > > > > > >> > > > > // Running in an older
> > runtime,
> > > so
> > > > > no
> > > > > > > > > tracking
> > > > > > > > > > > of
> > > > > > > > > > > > > > > > > SMT-modified
> > > > > > > > > > > > > > > > > > > >> topic
> > > > > > > > > > > > > > > > > > > >> > > > names
> > > > > > > > > > > > > > > > > > > >> > > > > or partitions
> > > > > > > > > > > > > > > > > > > >> > > > > put(records, Map.of());
> > > > > > > > > > > > > > > > > > > >> > > > > }
> > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > >> > > > > public void
> > > > > put(Collection<SinkRecord>
> > > > > > > > > > records,
> > > > > > > > > > > > > > > > > > Map<SinkRecord,
> > > > > > > > > > > > > > > > > > > >> > > > > TopicPartition>
> > > > > > updatedTopicPartitions)
> > > > > > > {
> > > > > > > > > > > > > > > > > > > >> > > > > // real logic here
> > > > > > > > > > > > > > > > > > > >> > > > > }
> > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > >> > > > > This seems a lot easier than
> > > > having
> > > > > to
> > > > > > > use
> > > > > > > > > > > > try-catch
> > > > > > > > > > > > > > > > logic,
> > > > > > > > > > > > > > > > > > yet
> > > > > > > > > > > > > > > > > > > >> still
> > > > > > > > > > > > > > > > > > > >> > > > > allows sink connectors to
> > > utilize
> > > > > the
> > > > > > > new
> > > > > > > > > > > > > > functionality
> > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > > still
> > > > > > > > > > > > > > > > > > > >> > work
> > > > > > > > > > > > > > > > > > > >> > > > with
> > > > > > > > > > > > > > > > > > > >> > > > > older Connect runtimes.
> > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > >> > > > > WDYT?
> > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > >> > > > > Randall
> > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > >> > > > > On Thu, Sep 8, 2022 at 7:03
> AM
> > > > Yash
> > > > > > > Mayya
> > > > > > > > <
> > > > > > > > > > > > > > > > > > yash.mayya@gmail.com
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > >> > > wrote:
> > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > >> > > > > > Hi all,
> > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > >> > > > > > I would like to (re)start
> a
> > > new
> > > > > > > > discussion
> > > > > > > > > > > > thread
> > > > > > > > > > > > > on
> > > > > > > > > > > > > > > > > KIP-793
> > > > > > > > > > > > > > > > > > > >> (Kafka
> > > > > > > > > > > > > > > > > > > >> > > > > > Connect) which proposes
> some
> > > > > > additions
> > > > > > > > to
> > > > > > > > > > the
> > > > > > > > > > > > > public
> > > > > > > > > > > > > > > > > > > SinkRecord
> > > > > > > > > > > > > > > > > > > >> > > > interface
> > > > > > > > > > > > > > > > > > > >> > > > > > in order to support topic
> > > > mutating
> > > > > > > SMTs
> > > > > > > > > for
> > > > > > > > > > > sink
> > > > > > > > > > > > > > > > > connectors
> > > > > > > > > > > > > > > > > > > >> that do
> > > > > > > > > > > > > > > > > > > >> > > > their
> > > > > > > > > > > > > > > > > > > >> > > > > > own offset tracking.
> > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > >> > > > > > Links:
> > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > >> > > > > > KIP:
> > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=191336830
> > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > >> > > > > > Older discussion thread:
> > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >
> > > > > > > > >
> > > https://lists.apache.org/thread/00kcth6057jdcsyzgy1x8nb2s1cymy8h
> > > > > > > > > > ,
> > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >
> > > > > > > > >
> > > https://lists.apache.org/thread/rzqkm0q5y5v3vdjhg8wqppxbkw7nyopj
> > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > >> > > > > > Jira:
> > > > > > > > > > > > > > >
> > https://issues.apache.org/jira/browse/KAFKA-13431
> > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > >> > > > > > Thanks,
> > > > > > > > > > > > > > > > > > > >> > > > > > Yash
> > > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
>

Re: [DISCUSS] KIP-793: Sink Connectors: Support topic-mutating SMTs for async connectors (preCommit users)

[Chris Egerton <ch...@aiven.io.INVALID>]

Hi Yash,

I've been following the discussion and have some thoughts. Ultimately I'm
still in favor of this KIP and would hate to see it go dormant, though we
may end up settling for a less-invasive option.


On the topic of abstraction and inter-plugin interactions:

First, there already are instances of cross-plugin interactions. Logical
type handling is probably the biggest example: a source connector embeds
metadata in the schema for record keys/values it emits that notifies
downstream converters about how to handle them. We provide support for some
logical types in Connect out of the box, but there's nothing stopping
connector and converter developers from implementing their own logical type
support using the exact same mechanism and different logical type names,
which is already done by Debezium, to name one example.

Second, although it's been a goal of Connect to abstract away parts of
building a data pipeline so that, e.g., connector developers don't have to
be concerned with converters or consumers, in reality, this layer of
abstraction has already been eroded. The example that most-readily comes to
mind is how source tasks are notified of the offsets of records that
they've emitted after they've been published to Kafka via
SourceTask::commitRecord [1].

But, more importantly, it's unlikely that connectors are being developed in
complete isolation. Nobody's going to implement the SinkConnector /
SinkTask interfaces and then throw that code off to someone else to figure
out all the details of deployment, configuration, testing, etc. Developers
will probably have to be aware of at least the converter interface, some of
the available implementations of it, and some details of Kafka clients
(e.g., consumer groups for sink connectors). And this isn't a bad
thing--it's unlikely that someone will write a Kafka connector without
having or benefitting from some understanding of Kafka and the steps of the
data pipeline that it will be a part of.

Bringing this to the practical topic of discussion--transformations--I
think it's actually in everyone's best interests for connector developers
to be aware of transformations. This isn't just because of the specific
problem that the KIP is trying to address. It's because there's plenty of
logic that can be implemented via SMT that a naive connector developer will
think that they have to implement on their own, which will ultimately lead
to a sub-par experience for people who end up using those connectors due to
inconsistent semantics (especially lack of predicates), inconsistent
configuration syntax, increased chances for bugs, and FUD ("why wasn't this
implemented as an SMT?").

Finally, although preserving clean, composable interfaces that can be
understood in isolation is a great principle to start with, we are now in
what Anna McDonald recently referred to as "brownfield" space for Connect.
We can't go back in time and redesign the SMT interface/contracts to make
things cleaner. And I don't think it's fair to anyone to suddenly drop
support for SMTs that mutate t/p/o information for sink records, especially
since these can be used gainfully with plenty of existing sink connectors.

Ultimately I still think the path forward that's best for the users is to
make the impossible possible by addressing this long-standing API gap in
Connect. Yes, it adds to the cognitive burden for connector developers, but
if they can tolerate it, the end result is better for everyone involved,
and if they can't, it's likely that the end result will be a preservation
of existing behavior, which leaves us no worse than before.


With all that said, I've thought about how to minimize or at least hide the
API changes as much as possible. I've had two thoughts:

1. On the
SinkRecord::originalTopic/originalKafkaPartition/originalKafkaOffset front,
we could replace these methods with headers that the Connect runtime
automatically injects into records directly before dispatching them to
SinkTask::put. The names can be the proposed method names (e.g.,
"originalTopic"). I believe this is inferior to the current proposal and
should be a rejected alternative, but it at least seemed worth floating in
the name of compromise. I dislike this approach for two reasons: first, it
seems even less intuitive, and second, it doesn't come with the benefit of
encouraging connector developers to understand the SMT interface and take
it into account when designing connectors.

2. Although I'd hate to see the same bookkeeping logic implemented in
multiple connectors, we can consider eliminating the overridden
SinkTask::open/close methods. A note should be added to both methods
clarifying that they are only invoked with the original, pre-transform
topic partitions, and developers will be on their own if they want to deal
with post-transform topic partitions instead. I'm on the fence with this
one, but if it's a choice between passing this KIP without modifying
SinkTask::open/close, or letting the KIP go dormant, I'd happily choose the
former.

Thanks Yash and Greg for the discussion so far, and apologies for the wall
of text. Looking forward to your thoughts.

Cheers,

Chris

[1] -
https://kafka.apache.org/34/javadoc/org/apache/kafka/connect/source/SourceTask.html#commitRecord(org.apache.kafka.connect.source.SourceRecord,org.apache.kafka.clients.producer.RecordMetadata)

On Sun, Apr 23, 2023 at 11:20 AM Yash Mayya <ya...@gmail.com> wrote:

> Hi Greg,
>
> Thanks for the response and sorry for the late reply.
>
> > Currently the AK tests have a lot of calls to, for example, new
> > SinkRecord(String topic, int partition, Schema keySchema,
> > Object key, Schema valueSchema, Object value, long kafkaOffset)
> > , a constructor without the original T/P/O values. I assumed that for
> > backwards compatibility these constructors would still be usable in
> > new runtimes. I imagine that there are also tests in downstream projects
> > which make use of these constructors, whenever a Transform, Predicate,
> > or Task is tested without a corresponding Converter. My question was
> > about what values are chosen for the original T/P/O methods when these
> > constructors are used after an upgrade to the latest connect-api.
>
> That's a good question - since this should only primarily affect testing I
> think it should be acceptable to simply use the topic, partition and
> kafkaOffset values as the originalTopic, originalKafkaPartition
> and originalKafkaOffset?
>
> > If you inject the original T/P/O only before and after the chain, SMTs
> > after an SMT which changes the original T/P/O will see whatever the
> earlier
> > SMT emitted. Is this intentional, or should this be avoided?
>
> Hmm, this sounds like a misbehaving / badly implemented SMTs since there
> doesn't seem to be any reasonable situation where an SMT should modify a
> sink record's original topic / partition / offset data so I'm not in favor
> of introducing checks and guards in the framework for this.
>
> Another point that I've been pondering about is the one you raised about
> the composability of Connect's plugin ecosystem and the special case
> handling we're adding to sink connector plugins to work with certain
> transformation plugin types. This really doesn't seem like a good precedent
> to be setting / starting (since there don't seem to be any other such
> "snowflake" inter-plugin interactions) in my opinion. The alternative of
> completely managing this in the framework (and only exposing the virtual
> coordinates to the sink tasks) doesn't seem too appealing either due to the
> backward compatibility concerns while maintaining existing support and
> functionality such as the possibility of implementing exactly-once
> semantics, ability for tasks to rewind consumer offsets arbitrarily (which
> might require the introduction of some form of persistence for the physical
> <-> virtual coordinate mapping) etc. Unfortunately, even though this is a
> long standing problem that all of us want to fix, I'm considering moving
> this KIP into a dormant / inactive state since there doesn't seem to be a
> design that satisfies all the general principles that the Kafka Connect
> framework has striven to uphold.
>
> Thanks,
> Yash
>
> On Tue, Mar 14, 2023 at 3:31 AM Greg Harris <gr...@aiven.io.invalid>
> wrote:
>
> > Yash,
> >
> > > 'm not sure I follow - are you asking about how the tests will be
> updated
> > post this change or about how upgrades will look like for clusters in
> > production?
> >
> > Currently the AK tests have a lot of calls to, for example, new
> > SinkRecord(String topic, int partition, Schema keySchema, Object key,
> > Schema valueSchema, Object value, long kafkaOffset), a constructor
> without
> > the original T/P/O values. I assumed that for backwards compatibility
> these
> > constructors would still be usable in new runtimes.
> > I imagine that there are also tests in downstream projects which make use
> > of these constructors, whenever a Transform, Predicate, or Task is tested
> > without a corresponding Converter. My question was about what values are
> > chosen for the original T/P/O methods when these constructors are used
> > after an upgrade to the latest connect-api.
> >
> > > There shouldn't be any difference in behavior here - the framework will
> > add
> > the original T/P/O metadata to the record after the entire transformation
> > chain has been applied and just before sending the record to the task for
> > processing. The KIP doesn't propose that transformations themselves
> should
> > also be able to retrieve original T/P/O information for a sink record.
> >
> > The KIP includes this: "Note that while the record's offset can't be
> > modified via the standard SinkRecord::newRecord methods that SMTs are
> > expected to use, SinkRecord has public constructors that would allow SMTs
> > to return records with modified offsets. This is why the proposed changes
> > include a new SinkRecord::originalKafkaOffset method as well."
> > In order to use the new or old SinkRecord constructors outside of the
> > newRecord methods, SMTs will downcast the previous record and may access
> > the original T/P/O methods. They may or may not forward this to the next
> > SMT, and they may or may not use it in their own computation.
> > Since this is acknowledged as a possible implementation, I was just
> asking
> > about when one SMT changes the original T/P/O, what should later SMTs and
> > predicates see from the original T/P/O methods?
> > If you inject the original T/P/O only before and after the chain, SMTs
> > after an SMT which changes the original T/P/O will see whatever the
> earlier
> > SMT emitted. Is this intentional, or should this be avoided?
> > For existing SMTs use the SinkRecord constructor, either directly or via
> > subclasses of ConnectRecord, they will drop the original T/P/O and fall
> > back to the logic from question (1).
> >
> > > The rejected alternative basically says that we can't do a
> > deterministic mapping from virtual coordinates to physical coordinates
> > without doing a lot of book-keeping.
> >
> > I suppose there is a possible implementation of metadata book-keeping
> which
> > provides a reasonable system of virtual coordinates, it just ended up
> > equivalent to hydrating intermediate topics to compute a consistent
> record
> > ordering. I wasn't convinced by calling it "book-keeping" since i've seen
> > that phrase used to disregard much less complicated state management, and
> > had to see exactly where that solution becomes unreasonable.
> >
> > Thanks,
> > Greg
> >
> > On Sun, Mar 12, 2023 at 6:30 AM Yash Mayya <ya...@gmail.com> wrote:
> >
> > > Hi Greg,
> > >
> > > Thanks for the detailed review!
> > >
> > > > What is the expected state/behavior for SinkRecords
> > > > which do not have original T/P/O information after the
> > > > upgrade? Just browsing, it appears that tests make
> > > > extensive use of the existing public SinkRecord
> > > > constructors  for both Transformations and Connectors.
> > >
> > > I'm not sure I follow - are you asking about how the tests will be
> > updated
> > > post this change or about how upgrades will look like for clusters in
> > > production? For the latter, we won't have to worry about sink records
> > > without original T/P/O information at all once a cluster is fully
> rolled
> > > and we will make it (hopefully) abundantly clear that connectors need
> to
> > > account for missing original T/P/O getter methods if they expect to be
> > > deployed on older Connect runtimes.
> > >
> > > > What is the expected behavior for Transformation
> > > > implementations which do not use the newRecord
> > > > methods and instead use public SinkRecord constructors?
> > > > The KIP mentions this as a justification for the
> > > > originalKafkaOffset method, but if existing implementations
> > > > are using the existing constructors, those constructors won't
> > > > forward the original T/P/O information to later transforms or
> > > > the task.
> > >
> > > There shouldn't be any difference in behavior here - the framework will
> > add
> > > the original T/P/O metadata to the record after the entire
> transformation
> > > chain has been applied and just before sending the record to the task
> for
> > > processing. The KIP doesn't propose that transformations themselves
> > should
> > > also be able to retrieve original T/P/O information for a sink record.
> > >
> > > > This reasoning and the KIP design seems to imply that the
> > > > connector is better equipped to solve this problem than the
> > > > framework, but the stated reasons are not convincing for me.
> > >
> > > This was added to the KIP by the original author, but I don't think the
> > > intention was to imply that the connector is better equipped to solve
> > this
> > > problem than the framework. The intention is to provide complete
> > > information to the connector ("physical" and "virtual coordinates"
> > instead
> > > of the currently incomplete "virtual coordinates" as you've termed it)
> so
> > > that connectors can use the virtual coordinates for writing data to the
> > > sink system and physical coordinates for offset reporting back to the
> > > framework. The rejected alternative basically says that we can't do a
> > > deterministic mapping from virtual coordinates to physical coordinates
> > > without doing a lot of book-keeping.
> > >
> > > I agree with the rest of your analysis on the tradeoffs between the
> > > proposed approach versus the seemingly more attractive approach of
> > handling
> > > everything purely in the framework and only exposing "virtual
> > coordinates"
> > > to the connectors. I think the biggest thorn here is maintaining
> backward
> > > compatibility with the considerable ecosystem of existing connectors
> > which
> > > is something Connect has always been burdened by.
> > >
> > > Thanks,
> > > Yash
> > >
> > > On Wed, Mar 8, 2023 at 6:54 AM Greg Harris
> <greg.harris@aiven.io.invalid
> > >
> > > wrote:
> > >
> > > > Hi Yash,
> > > >
> > > > I always use this issue as an example of a bug being caused by design
> > > > rather than by implementation error, and once it's fixed I'll need to
> > > find
> > > > something else to talk about :)
> > > > So glad to see this get fixed!
> > > >
> > > > I'll chime in to support some of the earlier discussions that seem to
> > > have
> > > > been resolved:
> > > >
> > > > 1. With respect to SinkRecord methods vs an overloaded put(): I agree
> > > with
> > > > the current design but I justify it a little bit differently than has
> > > > already been discussed.
> > > > If we were designing this interface on day 1 without backwards
> > > > compatibility in mind, which design would make more sense? Or for a
> > > > different framing: In the future when old runtimes and connectors are
> > > > retired and the old interfaces are removed, which design is going to
> > look
> > > > more strange and unmotivated?
> > > > Applied to this design decision, I would say that the original T/P/O
> > are
> > > > properties of a single SinkRecord and make sense as getters, and it
> > would
> > > > be strange to store them in an auxiliary map.
> > > >
> > > > 2. Following up this change with a compatibility library to make the
> > > > interface easier to use is the right choice to make here. This change
> > > > should be focused on correctness in allowing developers to fix the
> > > > incompatibility and we can be concerned with coming up with a more
> > > > ergonomic solution in the compatibility library.
> > > > The API should be focused on generality, correctness, and performance
> > > > because those cannot be worked-around after the fact. Connector
> > > > implementations and/or libraries can be concerned with trading off
> some
> > > > generality and/or performance for ease-of-use.
> > > >
> > > > 3. I think that the difference in behavior of the new open/close
> > methods
> > > as
> > > > compared to the old methods is significant, and requires good
> > > documentation
> > > > to help connector developers avoid lazy and incorrect migrations. I
> am
> > > > happy to have that addressed in code review after the KIP is
> approved.
> > > >
> > > > I had some questions:
> > > >
> > > > 4. What is the expected state/behavior for SinkRecords which do not
> > have
> > > > original T/P/O information after the upgrade? Just browsing, it
> appears
> > > > that tests make extensive use of the existing public SinkRecord
> > > > constructors for both Transformations and Connectors.
> > > >
> > > > 5. What is the expected behavior for Transformation implementations
> > which
> > > > do not use the newRecord methods and instead use public SinkRecord
> > > > constructors? The KIP mentions this as a justification for the
> > > > originalKafkaOffset method, but if existing implementations are using
> > the
> > > > existing constructors, those constructors won't forward the original
> > > T/P/O
> > > > information to later transforms or the task.
> > > >
> > > > For the last few points, I want to discuss this rejected alternative:
> > > >
> > > > > Address the offsets problem entirely within the framework, doing
> some
> > > > kind of mapping from the transformed topic back to the original
> topic.
> > > > > * This would only work in the cases where there’s no overlap
> between
> > > the
> > > > transformed topic names, but would break for the rest of the
> > > > transformations (e.g. static transformation, topic = “a”).
> > > > > * Even if we wanted to limit the support to those cases, it would
> > > require
> > > > considerable bookkeeping to add a validation to verify that the
> > > > transformation chain adheres to that expectation (and fail fast if it
> > > > doesn’t).
> > > >
> > > > 6. This reasoning and the KIP design seems to imply that the
> connector
> > is
> > > > better equipped to solve this problem than the framework, but the
> > stated
> > > > reasons are not convincing for me.
> > > > * A static transformation still causes an offset collision in the
> > > connector
> > > > * The connector is not permitted to see the transformation chain to
> do
> > > any
> > > > fail-fast assertions
> > > >
> > > > Suppose we were to think of the records at the end of the
> > transformation
> > > > chain as being in "virtual partitions" with "virtual offsets".
> > > > For example, with identity-routing SMTs, the virtual coordinates are
> > > > exactly the same as the underlying physical coordinates. For 1-1
> > renames,
> > > > each virtual topic would be the renamed topic corresponding to the
> > > > underlying topic. For fan-out from one topic to multiple virtual
> > topics,
> > > > virtual offsets would use the underlying kafka offsets with gaps for
> > > > records going to other virtual partitions. Virtual topics with
> dropped
> > > > records have similar gaps in the offsets.
> > > > Currently, these virtual coordinates are passed into the connector
> via
> > > > SinkTask::put, but SinkTask::open/close/preCommit and
> > > > SinkTaskContext::assignment/offsets/pause/resume all use physical
> > > > coordinates.
> > > > This proposal patches put,open, and close to have both physical and
> > > virtual
> > > > coordinates, but leaves the other methods with physical coordinates.
> > > After
> > > > this proposal, connectors would be intentionally made aware of the
> > > > distinction between physical and virtual coordinates, and manage
> their
> > > own
> > > > bookkeeping for the two systems.
> > > >
> > > > To avoid that connector logic, we could use virtual coordinates in
> all
> > > > connector calls, never revealing that they are different from the
> > > physical
> > > > coordinates. There's a whole design shopping list that we'd need:
> > > > * Renumbering mechanism for disambiguating and making virtual offsets
> > > > monotonic in the case of topic/partition collisions
> > > > * Data structure and strategy for translating virtual offsets back to
> > > > physical offsets
> > > > * New limits on SinkTaskContext::offsets() calls to prevent rewinding
> > > > before the latest commit
> > > > * Backwards compatibility and upgrade design
> > > >
> > > > 7. This alternative was very appealing to me, because the strength
> of a
> > > > plugin framework is the composability of different components. Among
> a
> > > > collection of N connectors and M transforms, it should ideally only
> > take
> > > > N + M work to understand how the components combine to build the
> whole.
> > > > However, once you start adding special cases to some plugins to
> support
> > > > interactions with others, the whole system can take N * M work to
> > > > understand. From a complexity standpoint, it would be very good for
> the
> > > > framework to solve this in a way which was connector-agnostic.
> > > > The current design compromises the logical isolation of the plugins
> > > > slightly, but they can collapse offsets very memory-efficiently, and
> > > re-use
> > > > the existing raw coordinate functions and keep everything else
> > backwards
> > > > compatible. After deriving all of the above, I think that's a
> > reasonable
> > > > tradeoff to make.
> > > >
> > > > Thanks,
> > > > Greg
> > > >
> > > > On Tue, Feb 21, 2023 at 10:17 AM Chris Egerton
> <chrise@aiven.io.invalid
> > >
> > > > wrote:
> > > >
> > > > > Hi Yash,
> > > > >
> > > > > We'll probably want to make a few tweaks to the Javadocs for the
> new
> > > > > methods (I'm imagining that notes on compatibility with older
> > versions
> > > > will
> > > > > be required), but I believe what's proposed in the KIP is good
> enough
> > > to
> > > > > approve with the understanding that it may not exactly match what
> > gets
> > > > > implemented/merged.
> > > > >
> > > > > LGTM, thanks again for the KIP!
> > > > >
> > > > > Cheers,
> > > > >
> > > > > Chris
> > > > >
> > > > > On Tue, Feb 21, 2023 at 12:18 PM Yash Mayya <ya...@gmail.com>
> > > > wrote:
> > > > >
> > > > > > Hi Chris,
> > > > > >
> > > > > > > we might try to introduce a framework-level configuration
> > > > > > > property to dictate which of the pre-transform and
> post-transform
> > > > > > > topic partitions are used for the fallback call to the
> single-arg
> > > > > > > variant if a task class has not overridden the multi-arg
> variant
> > > > > >
> > > > > > Thanks for the explanation and I agree that this will be a tad
> bit
> > > too
> > > > > > convoluted. :)
> > > > > >
> > > > > > Please do let me know if you'd like any further amendments to the
> > > KIP!
> > > > > >
> > > > > > Thanks,
> > > > > > Yash
> > > > > >
> > > > > > On Tue, Feb 21, 2023 at 8:42 PM Chris Egerton
> > > <chrise@aiven.io.invalid
> > > > >
> > > > > > wrote:
> > > > > >
> > > > > > > Hi Yash,
> > > > > > >
> > > > > > > I think the use case for pre-transform TPO coordinates (and
> topic
> > > > > > partition
> > > > > > > writers created/destroyed in close/open) tends to boil down to
> > > > > > exactly-once
> > > > > > > semantics, where it's desirable to preserve the guarantees that
> > > Kafka
> > > > > > > provides (every record has a unique TPO trio, and records are
> > > ordered
> > > > > by
> > > > > > > offset within a topic partition).
> > > > > > >
> > > > > > > It's my understanding that this approach is utilized in several
> > > > > > connectors
> > > > > > > out there today, and it might break these connectors to start
> > using
> > > > the
> > > > > > > post-transform topic partitions automatically in their
> open/close
> > > > > > methods.
> > > > > > >
> > > > > > > If we want to get really fancy with this and try to obviate or
> at
> > > > least
> > > > > > > reduce the need for per-connector code changes, we might try to
> > > > > > introduce a
> > > > > > > framework-level configuration property to dictate which of the
> > > > > > > pre-transform and post-transform topic partitions are used for
> > the
> > > > > > fallback
> > > > > > > call to the single-arg variant if a task class has not
> overridden
> > > the
> > > > > > > multi-arg variant. But I think this is going a bit too far and
> > > would
> > > > > > prefer
> > > > > > > to keep things simple(r) for now.
> > > > > > >
> > > > > > > Cheers,
> > > > > > >
> > > > > > > Chris
> > > > > > >
> > > > > > >
> > > > > > > On Sun, Feb 19, 2023 at 2:34 AM Yash Mayya <
> yash.mayya@gmail.com
> > >
> > > > > wrote:
> > > > > > >
> > > > > > > > Hi Chris,
> > > > > > > >
> > > > > > > > > I was actually envisioning something like `void
> > > > > > > > > open(Collection<TopicPartition> originalPartitions,
> > > > > > > > > Collection<TopicPartition> transformedPartitions)`
> > > > > > > >
> > > > > > > > Ah okay, this does make a lot more sense. Sorry, I think I
> > > > > > misunderstood
> > > > > > > > you earlier. I do agree with you that this seems better than
> > > > > splitting
> > > > > > it
> > > > > > > > off into two new sets of open / close methods from a
> complexity
> > > > > > > standpoint.
> > > > > > > >
> > > > > > > > > Plus, if a connector is intentionally designed to use
> > > > > > > > > pre-transformation topic partitions in its open/close
> > > > > > > > > methods, wouldn't we just be trading one form of the
> > > > > > > > >  problem for another by making this switch?
> > > > > > > >
> > > > > > > > On thinking about this a bit more, I'm not so convinced that
> we
> > > > need
> > > > > to
> > > > > > > > expose the pre-transform / original topic partitions in the
> new
> > > > open
> > > > > /
> > > > > > > > close methods. The purpose of the open / close methods is to
> > > allow
> > > > > sink
> > > > > > > > tasks to allocate and deallocate resources for each topic
> > > partition
> > > > > > > > assigned to the task and the purpose of topic-mutating SMTs
> is
> > to
> > > > > > > > essentially modify the source topic name from the point of
> view
> > > of
> > > > > the
> > > > > > > sink
> > > > > > > > connector. Why would a sink connector ever need to or want to
> > > > > allocate
> > > > > > > > resources for pre-transform topic partitions? Is the argument
> > > here
> > > > > that
> > > > > > > > since we'll be exposing both the pre-transform and
> > post-transform
> > > > > topic
> > > > > > > > partitions per record, we should also expose the same info
> via
> > > > open /
> > > > > > > close
> > > > > > > > and allow sink connector implementations to disregard
> > > > topic-mutating
> > > > > > SMTs
> > > > > > > > completely if they wanted to?
> > > > > > > >
> > > > > > > > Either way, I've gone ahead and updated the KIP to reflect
> all
> > of
> > > > > > > > our previous discussion here since it had become quite
> > outdated.
> > > > I've
> > > > > > > also
> > > > > > > > updated the KIP title from "Sink Connectors: Support
> > > topic-mutating
> > > > > > SMTs
> > > > > > > > for async connectors (preCommit users)" to "Allow sink
> > connectors
> > > > to
> > > > > be
> > > > > > > > used with topic-mutating SMTs" since the improvements to the
> > > open /
> > > > > > close
> > > > > > > > mechanism doesn't pertain only to asynchronous sink
> connectors.
> > > The
> > > > > new
> > > > > > > KIP
> > > > > > > > URL is:
> > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-793%3A+Allow+sink+connectors+to+be+used+with+topic-mutating+SMTs
> > > > > > > >
> > > > > > > >
> > > > > > > > Thanks,
> > > > > > > > Yash
> > > > > > > >
> > > > > > > > On Tue, Feb 14, 2023 at 11:39 PM Chris Egerton
> > > > > <chrise@aiven.io.invalid
> > > > > > >
> > > > > > > > wrote:
> > > > > > > >
> > > > > > > > > Hi Yash,
> > > > > > > > >
> > > > > > > > > I was actually envisioning something like `void
> > > > > > > > > open(Collection<TopicPartition>
> > > > > > > > > originalPartitions, Collection<TopicPartition>
> > > > > > transformedPartitions)`,
> > > > > > > > > since we already convert and transform each batch of
> records
> > > that
> > > > > we
> > > > > > > poll
> > > > > > > > > from the sink task's consumer en masse, meaning we could
> > > discover
> > > > > > > several
> > > > > > > > > new transformed partitions in between consecutive calls to
> > > > > > > SinkTask::put.
> > > > > > > > >
> > > > > > > > > It's also worth noting that we'll probably want to
> deprecate
> > > the
> > > > > > > existing
> > > > > > > > > open/close methods, at which point keeping one
> non-deprecated
> > > > > variant
> > > > > > > of
> > > > > > > > > each seems more appealing and less complex than keeping
> two.
> > > > > > > > >
> > > > > > > > > Honestly though, I think we're both on the same page enough
> > > that
> > > > I
> > > > > > > > wouldn't
> > > > > > > > > object to either approach. We've probably reached the
> > > saturation
> > > > > > point
> > > > > > > > for
> > > > > > > > > ROI here and as long as we provide developers a way to get
> > the
> > > > > > > > information
> > > > > > > > > they need from the runtime and take care to add Javadocs
> and
> > > > update
> > > > > > our
> > > > > > > > > docs page (possibly including the connector development
> > > > > quickstart),
> > > > > > it
> > > > > > > > > should be fine.
> > > > > > > > >
> > > > > > > > > At this point, it might be worth updating the KIP based on
> > > recent
> > > > > > > > > discussion so that others can see the latest proposal, and
> we
> > > can
> > > > > > both
> > > > > > > > take
> > > > > > > > > a look and make sure everything looks good enough before
> > > opening
> > > > a
> > > > > > vote
> > > > > > > > > thread.
> > > > > > > > >
> > > > > > > > > Finally, I think you make a convincing case for a
> time-based
> > > > > eviction
> > > > > > > > > policy. I wasn't thinking about the fairly common SMT
> pattern
> > > of
> > > > > > > > deriving a
> > > > > > > > > topic name from, e.g., a record field or header.
> > > > > > > > >
> > > > > > > > > Cheers,
> > > > > > > > >
> > > > > > > > > Chris
> > > > > > > > >
> > > > > > > > > On Tue, Feb 14, 2023 at 11:42 AM Yash Mayya <
> > > > yash.mayya@gmail.com>
> > > > > > > > wrote:
> > > > > > > > >
> > > > > > > > > > Hi Chris,
> > > > > > > > > >
> > > > > > > > > > > Plus, if a connector is intentionally designed to
> > > > > > > > > > > use pre-transformation topic partitions in its
> > > > > > > > > > > open/close methods, wouldn't we just be trading
> > > > > > > > > > > one form of the problem for another by making this
> > > > > > > > > > > switch?
> > > > > > > > > >
> > > > > > > > > > Thanks, this makes sense, and given that the KIP already
> > > > > proposes a
> > > > > > > way
> > > > > > > > > for
> > > > > > > > > > sink connector implementations to distinguish between
> > > > > pre-transform
> > > > > > > and
> > > > > > > > > > post-transform topics per record, I think I'm convinced
> > that
> > > > > going
> > > > > > > with
> > > > > > > > > new
> > > > > > > > > > `open()` / `close()` methods is the right approach.
> > However,
> > > I
> > > > > > still
> > > > > > > > feel
> > > > > > > > > > like having overloaded methods will make it a lot less
> > > > > unintuitive
> > > > > > > > given
> > > > > > > > > > that the two sets of methods would be different in terms
> of
> > > > when
> > > > > > > > they're
> > > > > > > > > > called and what arguments they are passed (also I'm
> > presuming
> > > > > that
> > > > > > > the
> > > > > > > > > > overloaded methods you're prescribing will only have a
> > single
> > > > > > > > > > `TopicPartition` rather than a
> `Collection<TopicPartition>`
> > > as
> > > > > > their
> > > > > > > > > > parameters). I guess my concern is largely around the
> fact
> > > that
> > > > > it
> > > > > > > > won't
> > > > > > > > > be
> > > > > > > > > > possible to distinguish between the overloaded methods'
> use
> > > > cases
> > > > > > > just
> > > > > > > > > from
> > > > > > > > > > the method signatures. I agree that naming is going to be
> > > > > difficult
> > > > > > > > here,
> > > > > > > > > > but I think that having two sets of `SinkTask::openXyz` /
> > > > > > > > > > `SinkTask::closeXyz` methods will be less complicated to
> > > > > understand
> > > > > > > > from
> > > > > > > > > a
> > > > > > > > > > connector developer perspective (as compared to
> overloaded
> > > > > methods
> > > > > > > with
> > > > > > > > > > only differing documentation). Of your suggested
> options, I
> > > > think
> > > > > > > > > > `openPreTransform` / `openPostTransform` are the most
> > > > > > comprehensible
> > > > > > > > > ones.
> > > > > > > > > >
> > > > > > > > > > > BTW, I wouldn't say that we can't make assumptions
> > > > > > > > > > > about the relationships between pre- and
> > > post-transformation
> > > > > > > > > > >  topic partitions.
> > > > > > > > > >
> > > > > > > > > > I meant that the framework wouldn't be able to
> > > > deterministically
> > > > > > know
> > > > > > > > > when
> > > > > > > > > > to close a post-transform topic partition given that SMTs
> > > could
> > > > > use
> > > > > > > > > > per-record data / metadata to manipulate the topic names
> as
> > > and
> > > > > how
> > > > > > > > > > required (which supports the suggestion to use an
> eviction
> > > > policy
> > > > > > > based
> > > > > > > > > > mechanism to call SinkTask::close for post-transform
> topic
> > > > > > > partitions).
> > > > > > > > > >
> > > > > > > > > > > We might utilize a policy that assumes a deterministic
> > > > > > > > > > > mapping from the former to the latter, for example.
> > > > > > > > > >
> > > > > > > > > > Wouldn't this be making the assumption that SMTs only use
> > the
> > > > > topic
> > > > > > > > name
> > > > > > > > > > itself and no other data / metadata while computing the
> new
> > > > topic
> > > > > > > name?
> > > > > > > > > Are
> > > > > > > > > > you suggesting that since this assumption could work for
> a
> > > > > majority
> > > > > > > of
> > > > > > > > > > SMTs, it might be more efficient overall in terms of
> > reducing
> > > > the
> > > > > > > > number
> > > > > > > > > of
> > > > > > > > > > "false-positive" calls to `SinkTask::closePostTransform`
> > (and
> > > > > we'll
> > > > > > > > also
> > > > > > > > > be
> > > > > > > > > > able to call `SinkTask::closePostTransform` immediately
> > after
> > > > > topic
> > > > > > > > > > partitions are revoked from the consumer)? I was thinking
> > > > > something
> > > > > > > > more
> > > > > > > > > > generic along the lines of a simple time based eviction
> > > policy
> > > > > that
> > > > > > > > > > wouldn't be making any assumptions regarding the SMT
> > > > > > implementations.
> > > > > > > > > > Either way, I do like your earlier suggestion of keeping
> > this
> > > > > logic
> > > > > > > > > > internal and not painting ourselves into a corner by
> > > promising
> > > > > any
> > > > > > > > > > particular behavior in the KIP.
> > > > > > > > > >
> > > > > > > > > > Thanks,
> > > > > > > > > > Yash
> > > > > > > > > >
> > > > > > > > > > On Tue, Feb 14, 2023 at 1:08 AM Chris Egerton
> > > > > > > <chrise@aiven.io.invalid
> > > > > > > > >
> > > > > > > > > > wrote:
> > > > > > > > > >
> > > > > > > > > > > Hi Yash,
> > > > > > > > > > >
> > > > > > > > > > > I think the key difference between adding
> > methods/overloads
> > > > > > related
> > > > > > > > to
> > > > > > > > > > > SinkTask::open/SinkTask::close and SinkTask::put is
> that
> > > this
> > > > > > isn't
> > > > > > > > > > > auxiliary information that may or may not be useful to
> > > > > connector
> > > > > > > > > > > developers. It's actually critical for them to
> understand
> > > the
> > > > > > > > > difference
> > > > > > > > > > > between the two concepts here, even if they look very
> > > > similar.
> > > > > > And
> > > > > > > > > yes, I
> > > > > > > > > > > do believe that switching from pre-transform to
> > > > post-transform
> > > > > > > topic
> > > > > > > > > > > partitions is too big a change in behavior here. Plus,
> > if a
> > > > > > > connector
> > > > > > > > > is
> > > > > > > > > > > intentionally designed to use pre-transformation topic
> > > > > partitions
> > > > > > > in
> > > > > > > > > its
> > > > > > > > > > > open/close methods, wouldn't we just be trading one
> form
> > of
> > > > the
> > > > > > > > problem
> > > > > > > > > > for
> > > > > > > > > > > another by making this switch?
> > > > > > > > > > >
> > > > > > > > > > > One possible alternative to overloading the existing
> > > methods
> > > > is
> > > > > > to
> > > > > > > > > split
> > > > > > > > > > > SinkTask::open into openOriginal (or possibly
> > openPhysical
> > > or
> > > > > > > > > > > openPreTransform) and openTransformed (or openLogical
> or
> > > > > > > > > > > openPostTransform), with a similar change for
> > > > SinkTask::close.
> > > > > > The
> > > > > > > > > > default
> > > > > > > > > > > implementation for SinkTask::openOriginal can be to
> call
> > > > > > > > > SinkTask::open,
> > > > > > > > > > > and the same can go for SinkTask::close. However, I
> > prefer
> > > > > > > > overloading
> > > > > > > > > > the
> > > > > > > > > > > existing methods since this alternative increases
> > > complexity
> > > > > and
> > > > > > > none
> > > > > > > > > of
> > > > > > > > > > > the names are very informative.
> > > > > > > > > > >
> > > > > > > > > > > BTW, I wouldn't say that we can't make assumptions
> about
> > > the
> > > > > > > > > > relationships
> > > > > > > > > > > between pre- and post-transformation topic partitions.
> We
> > > > might
> > > > > > > > > utilize a
> > > > > > > > > > > policy that assumes a deterministic mapping from the
> > former
> > > > to
> > > > > > the
> > > > > > > > > > latter,
> > > > > > > > > > > for example. The distinction I'd draw is that the
> > > assumptions
> > > > > we
> > > > > > > make
> > > > > > > > > can
> > > > > > > > > > > and probably should favor some cases in terms of
> > > performance
> > > > > > (i.e.,
> > > > > > > > > > > reducing the number of unnecessary calls to close/open
> > > over a
> > > > > > given
> > > > > > > > > sink
> > > > > > > > > > > task's lifetime), but should not lead to guaranteed
> > > resource
> > > > > > leaks
> > > > > > > or
> > > > > > > > > > > failure to obey API contract in any cases.
> > > > > > > > > > >
> > > > > > > > > > > Cheers,
> > > > > > > > > > >
> > > > > > > > > > > Chris
> > > > > > > > > > >
> > > > > > > > > > > On Mon, Feb 13, 2023 at 10:54 AM Yash Mayya <
> > > > > > yash.mayya@gmail.com>
> > > > > > > > > > wrote:
> > > > > > > > > > >
> > > > > > > > > > > > Hi Chris,
> > > > > > > > > > > >
> > > > > > > > > > > > > especially if connectors are intentionally designed
> > > > around
> > > > > > > > > > > > > original topic partitions instead of transformed
> > ones.
> > > > > > > > > > > >
> > > > > > > > > > > > Ha, that's a good point and reminds me of Hyrum's Law
> > [1]
> > > > :)
> > > > > > > > > > > >
> > > > > > > > > > > > > I think we have to provide connector developers
> with
> > > some
> > > > > > > > > > > > > way to differentiate between the two, but maybe
> > > there's a
> > > > > way
> > > > > > > > > > > > >  to do this that I haven't thought of yet
> > > > > > > > > > > >
> > > > > > > > > > > > I can't think of a better way to do this either;
> would
> > > > > invoking
> > > > > > > the
> > > > > > > > > > > > existing `SinkTask::open` and `SinkTask::close`
> methods
> > > > with
> > > > > > > > > > > post-transform
> > > > > > > > > > > > topic partitions instead of pre-transform topic
> > > partitions
> > > > > not
> > > > > > be
> > > > > > > > > > > > acceptable even in a minor / major AK release? I feel
> > > like
> > > > > the
> > > > > > > > > proposed
> > > > > > > > > > > > approach of adding overloaded `SinkTask::open` /
> > > > > > > `SinkTask::close`
> > > > > > > > > > > methods
> > > > > > > > > > > > to differentiate between pre-transform and
> > post-transform
> > > > > topic
> > > > > > > > > > > partitions
> > > > > > > > > > > > has similar pitfalls to the idea of the overloaded
> > > > > > > `SinkTask::put`
> > > > > > > > > > method
> > > > > > > > > > > > we discarded earlier.
> > > > > > > > > > > >
> > > > > > > > > > > > > Either way, I'm glad that the general idea of a
> cache
> > > and
> > > > > > > > > > > > > eviction policy for SinkTask::close seem
> reasonable;
> > if
> > > > > > > > > > > > > we decide to go this route, it might make sense for
> > the
> > > > KIP
> > > > > > > > > > > > > to include an outline of one or more high-level
> > > > strategies
> > > > > > > > > > > > > we might take, but without promising any particular
> > > > > behavior
> > > > > > > > > > > > > beyond occasionally calling SinkTask::close for
> > > > > > post-transform
> > > > > > > > > > > > > topic partitions. I'm hoping that this logic can
> stay
> > > > > > internal,
> > > > > > > > > > > > > and by notpainting ourselves into a corner with the
> > > KIP,
> > > > we
> > > > > > > > > > > > > give ourselves leeway to tweak it in the future if
> > > > > necessary
> > > > > > > > > > > > > without filing another KIP or introducing a
> pluggable
> > > > > > > interface.
> > > > > > > > > > > >
> > > > > > > > > > > > Thanks, that's a good idea. Given the flexibility of
> > > SMTs,
> > > > > the
> > > > > > > > > > framework
> > > > > > > > > > > > can't really make any assumptions around topic
> > partitions
> > > > > post
> > > > > > > > > > > > transformation nor does it have any way to
> definitively
> > > get
> > > > > any
> > > > > > > > such
> > > > > > > > > > > > information from transformations which is why the
> idea
> > > of a
> > > > > > cache
> > > > > > > > > with
> > > > > > > > > > an
> > > > > > > > > > > > eviction policy makes perfect sense!
> > > > > > > > > > > >
> > > > > > > > > > > > [1] - https://www.hyrumslaw.com/
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > > > Thanks,
> > > > > > > > > > > > Yash
> > > > > > > > > > > >
> > > > > > > > > > > > On Thu, Feb 9, 2023 at 9:38 PM Chris Egerton
> > > > > > > > <chrise@aiven.io.invalid
> > > > > > > > > >
> > > > > > > > > > > > wrote:
> > > > > > > > > > > >
> > > > > > > > > > > > > Hi Yash,
> > > > > > > > > > > > >
> > > > > > > > > > > > > > So it looks like with the current state of
> affairs,
> > > > sink
> > > > > > > tasks
> > > > > > > > > that
> > > > > > > > > > > > only
> > > > > > > > > > > > > instantiate writers in the SinkTask::open method
> (and
> > > > don't
> > > > > > do
> > > > > > > > the
> > > > > > > > > > lazy
> > > > > > > > > > > > > instantiation in SinkTask::put that you mentioned)
> > > might
> > > > > fail
> > > > > > > > when
> > > > > > > > > > used
> > > > > > > > > > > > > with topic/partition mutating SMTs even if they
> don't
> > > do
> > > > > any
> > > > > > > > > > > asynchronous
> > > > > > > > > > > > > processing?
> > > > > > > > > > > > >
> > > > > > > > > > > > > Yep, exactly 👍
> > > > > > > > > > > > >
> > > > > > > > > > > > > > What do you think about retaining just the
> existing
> > > > > methods
> > > > > > > > > > > > > but changing when they're called in the Connect
> > > runtime?
> > > > > For
> > > > > > > > > > instance,
> > > > > > > > > > > > > instead of calling SinkTask::open after partition
> > > > > assignment
> > > > > > > > post a
> > > > > > > > > > > > > consumer group rebalance, we could cache the
> > currently
> > > > > "seen"
> > > > > > > > topic
> > > > > > > > > > > > > partitions (post transformation) and before each
> call
> > > to
> > > > > > > > > > SinkTask::put
> > > > > > > > > > > > > check whether there's any new "unseen" topic
> > > partitions,
> > > > > and
> > > > > > if
> > > > > > > > so
> > > > > > > > > > call
> > > > > > > > > > > > > SinkTask::open (and also update the cache of
> course).
> > > > > > > > > > > > >
> > > > > > > > > > > > > IMO the issue here is that it's a drastic change in
> > > > > behavior
> > > > > > to
> > > > > > > > > start
> > > > > > > > > > > > > invoking SinkTask::open and SinkTask::close with
> > > > > > post-transform
> > > > > > > > > topic
> > > > > > > > > > > > > partitions instead of pre-transform, especially if
> > > > > connectors
> > > > > > > are
> > > > > > > > > > > > > intentionally designed around original topic
> > partitions
> > > > > > instead
> > > > > > > > of
> > > > > > > > > > > > > transformed ones. I think we have to provide
> > connector
> > > > > > > developers
> > > > > > > > > > with
> > > > > > > > > > > > some
> > > > > > > > > > > > > way to differentiate between the two, but maybe
> > > there's a
> > > > > way
> > > > > > > to
> > > > > > > > do
> > > > > > > > > > > this
> > > > > > > > > > > > > that I haven't thought of yet. Interested to hear
> > your
> > > > > > > thoughts.
> > > > > > > > > > > > >
> > > > > > > > > > > > > Either way, I'm glad that the general idea of a
> cache
> > > and
> > > > > > > > eviction
> > > > > > > > > > > policy
> > > > > > > > > > > > > for SinkTask::close seem reasonable; if we decide
> to
> > go
> > > > > this
> > > > > > > > route,
> > > > > > > > > > it
> > > > > > > > > > > > > might make sense for the KIP to include an outline
> of
> > > one
> > > > > or
> > > > > > > more
> > > > > > > > > > > > > high-level strategies we might take, but without
> > > > promising
> > > > > > any
> > > > > > > > > > > particular
> > > > > > > > > > > > > behavior beyond occasionally calling
> SinkTask::close
> > > for
> > > > > > > > > > post-transform
> > > > > > > > > > > > > topic partitions. I'm hoping that this logic can
> stay
> > > > > > internal,
> > > > > > > > and
> > > > > > > > > > by
> > > > > > > > > > > > not
> > > > > > > > > > > > > painting ourselves into a corner with the KIP, we
> > give
> > > > > > > ourselves
> > > > > > > > > > leeway
> > > > > > > > > > > > to
> > > > > > > > > > > > > tweak it in the future if necessary without filing
> > > > another
> > > > > > KIP
> > > > > > > or
> > > > > > > > > > > > > introducing a pluggable interface.
> > > > > > > > > > > > >
> > > > > > > > > > > > > Cheers,
> > > > > > > > > > > > >
> > > > > > > > > > > > > Chris
> > > > > > > > > > > > >
> > > > > > > > > > > > > On Thu, Feb 9, 2023 at 7:39 AM Yash Mayya <
> > > > > > > yash.mayya@gmail.com>
> > > > > > > > > > > wrote:
> > > > > > > > > > > > >
> > > > > > > > > > > > > > Hi Chris,
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Thanks for the feedback.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 1) That's a fair point; while I did scan
> everything
> > > > > > publicly
> > > > > > > > > > > available
> > > > > > > > > > > > on
> > > > > > > > > > > > > > GitHub, you're right in that it won't cover all
> > > > possible
> > > > > > SMTs
> > > > > > > > > that
> > > > > > > > > > > are
> > > > > > > > > > > > > out
> > > > > > > > > > > > > > there. Thanks for the example use-case as well,
> > I've
> > > > > > updated
> > > > > > > > the
> > > > > > > > > > KIP
> > > > > > > > > > > to
> > > > > > > > > > > > > add
> > > > > > > > > > > > > > the two new proposed methods.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 2) So it looks like with the current state of
> > > affairs,
> > > > > sink
> > > > > > > > tasks
> > > > > > > > > > > that
> > > > > > > > > > > > > only
> > > > > > > > > > > > > > instantiate writers in the SinkTask::open method
> > (and
> > > > > don't
> > > > > > > do
> > > > > > > > > the
> > > > > > > > > > > lazy
> > > > > > > > > > > > > > instantiation in SinkTask::put that you
> mentioned)
> > > > might
> > > > > > fail
> > > > > > > > > when
> > > > > > > > > > > used
> > > > > > > > > > > > > > with topic/partition mutating SMTs even if they
> > don't
> > > > do
> > > > > > any
> > > > > > > > > > > > asynchronous
> > > > > > > > > > > > > > processing? Since they could encounter records in
> > > > > > > SinkTask::put
> > > > > > > > > > with
> > > > > > > > > > > > > > topics/partitions that they might not have
> created
> > > > > writers
> > > > > > > for.
> > > > > > > > > > > Thanks
> > > > > > > > > > > > > for
> > > > > > > > > > > > > > pointing this out, it's definitely another
> > > > > incompatibility
> > > > > > > that
> > > > > > > > > > needs
> > > > > > > > > > > > to
> > > > > > > > > > > > > be
> > > > > > > > > > > > > > called out and fixed. The overloaded method
> > approach
> > > is
> > > > > > > > > > interesting,
> > > > > > > > > > > > but
> > > > > > > > > > > > > > comes with the caveat of yet more new methods
> that
> > > will
> > > > > > need
> > > > > > > to
> > > > > > > > > be
> > > > > > > > > > > > > > implemented by existing connectors if they want
> to
> > > make
> > > > > use
> > > > > > > of
> > > > > > > > > this
> > > > > > > > > > > new
> > > > > > > > > > > > > > functionality. What do you think about retaining
> > just
> > > > the
> > > > > > > > > existing
> > > > > > > > > > > > > methods
> > > > > > > > > > > > > > but changing when they're called in the Connect
> > > > runtime?
> > > > > > For
> > > > > > > > > > > instance,
> > > > > > > > > > > > > > instead of calling SinkTask::open after partition
> > > > > > assignment
> > > > > > > > > post a
> > > > > > > > > > > > > > consumer group rebalance, we could cache the
> > > currently
> > > > > > "seen"
> > > > > > > > > topic
> > > > > > > > > > > > > > partitions (post transformation) and before each
> > call
> > > > to
> > > > > > > > > > > SinkTask::put
> > > > > > > > > > > > > > check whether there's any new "unseen" topic
> > > > partitions,
> > > > > > and
> > > > > > > if
> > > > > > > > > so
> > > > > > > > > > > call
> > > > > > > > > > > > > > SinkTask::open (and also update the cache of
> > > course). I
> > > > > > don't
> > > > > > > > > think
> > > > > > > > > > > > this
> > > > > > > > > > > > > > would break the existing contract with sink tasks
> > > where
> > > > > > > > > > > SinkTask::open
> > > > > > > > > > > > is
> > > > > > > > > > > > > > expected to be called for a topic partition
> before
> > > any
> > > > > > > records
> > > > > > > > > from
> > > > > > > > > > > the
> > > > > > > > > > > > > > topic partition are sent via SinkTask::put? The
> > > > > > > SinkTask::close
> > > > > > > > > > case
> > > > > > > > > > > > is a
> > > > > > > > > > > > > > lot trickier however, and would require some sort
> > of
> > > > > cache
> > > > > > > > > eviction
> > > > > > > > > > > > > policy
> > > > > > > > > > > > > > that would be deemed appropriate as you pointed
> out
> > > > too.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > Yash
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > On Mon, Feb 6, 2023 at 11:27 PM Chris Egerton
> > > > > > > > > > > <chrise@aiven.io.invalid
> > > > > > > > > > > > >
> > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Hi Yash,
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > I've had some time to think on this KIP and I
> > think
> > > > I'm
> > > > > > in
> > > > > > > > > > > agreement
> > > > > > > > > > > > > > about
> > > > > > > > > > > > > > > not blocking it on an official compatibility
> > > library
> > > > or
> > > > > > > > adding
> > > > > > > > > > the
> > > > > > > > > > > > > "ack"
> > > > > > > > > > > > > > > API for sink records.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > I only have two more thoughts:
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 1. Because it is possible to manipulate sink
> > record
> > > > > > > > partitions
> > > > > > > > > > and
> > > > > > > > > > > > > > offsets
> > > > > > > > > > > > > > > with the current API we provide for
> > > transformations,
> > > > I
> > > > > > > still
> > > > > > > > > > > believe
> > > > > > > > > > > > > > > methods should be added to the SinkRecord class
> > to
> > > > > expose
> > > > > > > the
> > > > > > > > > > > > original
> > > > > > > > > > > > > > > partition and offset, not just the original
> > topic.
> > > > The
> > > > > > > > > additional
> > > > > > > > > > > > > > cognitive
> > > > > > > > > > > > > > > burden from these two methods is going to be
> > > minimal
> > > > > > > anyways;
> > > > > > > > > > once
> > > > > > > > > > > > > users
> > > > > > > > > > > > > > > understand the difference between the
> transformed
> > > > topic
> > > > > > > name
> > > > > > > > > and
> > > > > > > > > > > the
> > > > > > > > > > > > > > > original one, it's going to be trivial for them
> > to
> > > > > > > understand
> > > > > > > > > how
> > > > > > > > > > > > that
> > > > > > > > > > > > > > same
> > > > > > > > > > > > > > > difference applies for partitions and offsets.
> > It's
> > > > not
> > > > > > > > enough
> > > > > > > > > to
> > > > > > > > > > > > scan
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > set of SMTs provided out of the box with
> Connect,
> > > > ones
> > > > > > > > > developed
> > > > > > > > > > by
> > > > > > > > > > > > > > > Confluent, or even everything available on
> > GitHub,
> > > > > since
> > > > > > > > there
> > > > > > > > > > may
> > > > > > > > > > > be
> > > > > > > > > > > > > > > closed-source projects out there that rely on
> > this
> > > > > > ability.
> > > > > > > > One
> > > > > > > > > > > > > potential
> > > > > > > > > > > > > > > use case could be re-routing partitions between
> > > Kafka
> > > > > and
> > > > > > > > some
> > > > > > > > > > > other
> > > > > > > > > > > > > > > sharded system.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > 2. We still have to address the SinkTask::open
> > [1]
> > > > and
> > > > > > > > > > > > SinkTask::close
> > > > > > > > > > > > > > [2]
> > > > > > > > > > > > > > > methods. If a connector writes to the external
> > > system
> > > > > > using
> > > > > > > > the
> > > > > > > > > > > > > > transformed
> > > > > > > > > > > > > > > topic partitions it reads from Kafka, then it's
> > > > > possible
> > > > > > > for
> > > > > > > > > the
> > > > > > > > > > > > > > connector
> > > > > > > > > > > > > > > to lazily instantiate writers for topic
> > partitions
> > > as
> > > > > it
> > > > > > > > > > encounters
> > > > > > > > > > > > > them
> > > > > > > > > > > > > > > from records provided in SinkTask::put.
> However,
> > > > > > connectors
> > > > > > > > > also
> > > > > > > > > > > > need a
> > > > > > > > > > > > > > way
> > > > > > > > > > > > > > > to de-allocate those writers (and the resources
> > > used
> > > > by
> > > > > > > them)
> > > > > > > > > > over
> > > > > > > > > > > > > time,
> > > > > > > > > > > > > > > which they can't do as easily. One possible
> > > approach
> > > > > here
> > > > > > > is
> > > > > > > > to
> > > > > > > > > > > > > overload
> > > > > > > > > > > > > > > SinkTask::open and SinkTask::close with
> variants
> > > that
> > > > > > > > > distinguish
> > > > > > > > > > > > > between
> > > > > > > > > > > > > > > transformed and original topic partitions, and
> > > > default
> > > > > to
> > > > > > > > > > invoking
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > existing methods with just the original topic
> > > > > partitions.
> > > > > > > We
> > > > > > > > > > would
> > > > > > > > > > > > then
> > > > > > > > > > > > > > > have several options for how the Connect
> runtime
> > > can
> > > > > > invoke
> > > > > > > > > these
> > > > > > > > > > > > > > methods,
> > > > > > > > > > > > > > > but in general, an approach that guarantees
> that
> > > > tasks
> > > > > > are
> > > > > > > > > > notified
> > > > > > > > > > > > of
> > > > > > > > > > > > > > > transformed topic partitions in SinkTask::open
> > > before
> > > > > any
> > > > > > > > > records
> > > > > > > > > > > for
> > > > > > > > > > > > > > that
> > > > > > > > > > > > > > > partition are given to it in SinkTask::put, and
> > > > makes a
> > > > > > > > > > best-effort
> > > > > > > > > > > > > > attempt
> > > > > > > > > > > > > > > to close transformed topic partitions that
> appear
> > > to
> > > > no
> > > > > > > > longer
> > > > > > > > > be
> > > > > > > > > > > in
> > > > > > > > > > > > > use
> > > > > > > > > > > > > > > based on some eviction policy, would probably
> be
> > > > > > > sufficient.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > [1] -
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://kafka.apache.org/33/javadoc/org/apache/kafka/connect/sink/SinkTask.html#open(java.util.Collection)
> > > > > > > > > > > > > > > [2] -
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://kafka.apache.org/33/javadoc/org/apache/kafka/connect/sink/SinkTask.html#close(java.util.Collection)
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Cheers,
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Chris
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > On Sat, Nov 5, 2022 at 5:46 AM Yash Mayya <
> > > > > > > > > yash.mayya@gmail.com>
> > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Hi Chris,
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Thanks a lot for your inputs!
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > would provide a simple, clean interface for
> > > > > > developers
> > > > > > > to
> > > > > > > > > > > > determine
> > > > > > > > > > > > > > > > > which features are supported by the version
> > of
> > > > the
> > > > > > > > Connect
> > > > > > > > > > > > runtime
> > > > > > > > > > > > > > > > > that their plugin has been deployed onto
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > I do like the idea of having such a public
> > > > > > compatibility
> > > > > > > > > > library
> > > > > > > > > > > -
> > > > > > > > > > > > I
> > > > > > > > > > > > > > > think
> > > > > > > > > > > > > > > > it would remove a lot of restrictions from
> > > > framework
> > > > > > > > > > development
> > > > > > > > > > > if
> > > > > > > > > > > > > it
> > > > > > > > > > > > > > > were
> > > > > > > > > > > > > > > > to be widely adopted.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > we might consider adding an API to "ack"
> sink
> > > > > records
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > I agree that this does seem like a more
> > intuitive
> > > > and
> > > > > > > clean
> > > > > > > > > > API,
> > > > > > > > > > > > but
> > > > > > > > > > > > > > I'm
> > > > > > > > > > > > > > > > concerned about the backward compatibility
> > > headache
> > > > > > we'd
> > > > > > > be
> > > > > > > > > > > > imposing
> > > > > > > > > > > > > on
> > > > > > > > > > > > > > > all
> > > > > > > > > > > > > > > > existing sink connectors. Connector
> developers
> > > will
> > > > > > have
> > > > > > > to
> > > > > > > > > > > > maintain
> > > > > > > > > > > > > > two
> > > > > > > > > > > > > > > > separate ways of doing offset management if
> > they
> > > > want
> > > > > > to
> > > > > > > > use
> > > > > > > > > > the
> > > > > > > > > > > > new
> > > > > > > > > > > > > > API
> > > > > > > > > > > > > > > > but continue supporting older versions of
> Kafka
> > > > > > Connect.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > For now, I've reverted the KIP to the
> previous
> > > > > > iteration
> > > > > > > > > which
> > > > > > > > > > > > > proposed
> > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > addition of a new `SinkRecord` method to
> obtain
> > > the
> > > > > > > > original
> > > > > > > > > > > Kafka
> > > > > > > > > > > > > > topic
> > > > > > > > > > > > > > > > pre-transformation. One thing to note is that
> > > I've
> > > > > > > removed
> > > > > > > > > the
> > > > > > > > > > > > method
> > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > obtaining the original Kafka partition after
> a
> > > > > cursory
> > > > > > > > search
> > > > > > > > > > > > showed
> > > > > > > > > > > > > > that
> > > > > > > > > > > > > > > > use cases for partition modifying SMTs are
> > > > primarily
> > > > > on
> > > > > > > the
> > > > > > > > > > > source
> > > > > > > > > > > > > > > > connector side.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > Yash
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > On Tue, Nov 1, 2022 at 9:22 PM Chris Egerton
> > > > > > > > > > > > <chrise@aiven.io.invalid
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Hi all,
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > I have more comments I'd like to make on
> this
> > > KIP
> > > > > > when
> > > > > > > I
> > > > > > > > > have
> > > > > > > > > > > > time
> > > > > > > > > > > > > > > (sorry
> > > > > > > > > > > > > > > > > for the delay, Yash, and thanks for your
> > > > > patience!),
> > > > > > > but
> > > > > > > > I
> > > > > > > > > > did
> > > > > > > > > > > > want
> > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > chime in and say that I'm also not sure
> about
> > > > > > > overloading
> > > > > > > > > > > > > > > SinkTask::put.
> > > > > > > > > > > > > > > > I
> > > > > > > > > > > > > > > > > share the concerns about creating an
> > intuitive,
> > > > > > simple
> > > > > > > > API
> > > > > > > > > > that
> > > > > > > > > > > > > Yash
> > > > > > > > > > > > > > > has
> > > > > > > > > > > > > > > > > raised. In addition, this approach doesn't
> > seem
> > > > > very
> > > > > > > > > > > > > > sustainable--what
> > > > > > > > > > > > > > > do
> > > > > > > > > > > > > > > > > we do if we encounter another case in the
> > > future
> > > > > that
> > > > > > > > would
> > > > > > > > > > > > > warrant a
> > > > > > > > > > > > > > > > > similar solution? We probably don't want to
> > > > create
> > > > > > > three,
> > > > > > > > > > four,
> > > > > > > > > > > > > etc.
> > > > > > > > > > > > > > > > > overloaded variants of the method, each of
> > > which
> > > > > > would
> > > > > > > > have
> > > > > > > > > > to
> > > > > > > > > > > be
> > > > > > > > > > > > > > > > > implemented by connector developers who
> want
> > to
> > > > > both
> > > > > > > > > leverage
> > > > > > > > > > > the
> > > > > > > > > > > > > > > latest
> > > > > > > > > > > > > > > > > and greatest connector APIs and maintain
> > > > > > compatibility
> > > > > > > > with
> > > > > > > > > > > > connect
> > > > > > > > > > > > > > > > > Clusters running older versions.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > I haven't been able to flesh this out into
> a
> > > > design
> > > > > > > worth
> > > > > > > > > > > > > publishing
> > > > > > > > > > > > > > in
> > > > > > > > > > > > > > > > its
> > > > > > > > > > > > > > > > > own KIP yet, but one alternative I've
> pitched
> > > to
> > > > a
> > > > > > few
> > > > > > > > > people
> > > > > > > > > > > > with
> > > > > > > > > > > > > > > > > generally positive interest has been to
> > develop
> > > > an
> > > > > > > > official
> > > > > > > > > > > > > > > compatibility
> > > > > > > > > > > > > > > > > library for Connect developers. This
> library
> > > > would
> > > > > be
> > > > > > > > > > released
> > > > > > > > > > > as
> > > > > > > > > > > > > its
> > > > > > > > > > > > > > > own
> > > > > > > > > > > > > > > > > Maven artifact (separate from connect-api,
> > > > > > > > connect-runtime,
> > > > > > > > > > > etc.)
> > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > would
> > > > > > > > > > > > > > > > > provide a simple, clean interface for
> > > developers
> > > > to
> > > > > > > > > determine
> > > > > > > > > > > > which
> > > > > > > > > > > > > > > > > features are supported by the version of
> the
> > > > > Connect
> > > > > > > > > runtime
> > > > > > > > > > > that
> > > > > > > > > > > > > > their
> > > > > > > > > > > > > > > > > plugin has been deployed onto. Under the
> > hood,
> > > > this
> > > > > > > > library
> > > > > > > > > > > might
> > > > > > > > > > > > > use
> > > > > > > > > > > > > > > > > reflection to determine whether classes,
> > > methods,
> > > > > > etc.
> > > > > > > > are
> > > > > > > > > > > > > available,
> > > > > > > > > > > > > > > but
> > > > > > > > > > > > > > > > > the developer wouldn't have to do anything
> > more
> > > > > than
> > > > > > > > check
> > > > > > > > > > (for
> > > > > > > > > > > > > > > example)
> > > > > > > > > > > > > > > > >
> > > > > `Features.SINK_TASK_ERRANT_RECORD_REPORTER.enabled()`
> > > > > > > to
> > > > > > > > > know
> > > > > > > > > > > at
> > > > > > > > > > > > > any
> > > > > > > > > > > > > > > > point
> > > > > > > > > > > > > > > > > in the lifetime of their connector/task
> > whether
> > > > > that
> > > > > > > > > feature
> > > > > > > > > > is
> > > > > > > > > > > > > > > provided
> > > > > > > > > > > > > > > > by
> > > > > > > > > > > > > > > > > the runtime.
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > One other high-level comment: this doesn't
> > > > address
> > > > > > > every
> > > > > > > > > > case,
> > > > > > > > > > > > but
> > > > > > > > > > > > > we
> > > > > > > > > > > > > > > > might
> > > > > > > > > > > > > > > > > consider adding an API to "ack" sink
> records.
> > > > This
> > > > > > > could
> > > > > > > > > use
> > > > > > > > > > > the
> > > > > > > > > > > > > > > > > SubmittedRecords class [1] (with some
> slight
> > > > > tweaks)
> > > > > > > > under
> > > > > > > > > > the
> > > > > > > > > > > > hood
> > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > track the latest-acked offset for each
> topic
> > > > > > partition.
> > > > > > > > > This
> > > > > > > > > > > way,
> > > > > > > > > > > > > > > > connector
> > > > > > > > > > > > > > > > > developers won't be responsible for
> tracking
> > > > > offsets
> > > > > > at
> > > > > > > > all
> > > > > > > > > > in
> > > > > > > > > > > > > their
> > > > > > > > > > > > > > > sink
> > > > > > > > > > > > > > > > > tasks (eliminating issues with the accuracy
> > of
> > > > > > > > > > > > post-transformation
> > > > > > > > > > > > > > > T/P/O
> > > > > > > > > > > > > > > > > sink record information), and they'll only
> > have
> > > > to
> > > > > > > notify
> > > > > > > > > the
> > > > > > > > > > > > > Connect
> > > > > > > > > > > > > > > > > framework when a record has been
> successfully
> > > > > > > dispatched
> > > > > > > > to
> > > > > > > > > > the
> > > > > > > > > > > > > > > external
> > > > > > > > > > > > > > > > > system. This provides a cleaner, friendlier
> > > API,
> > > > > and
> > > > > > > also
> > > > > > > > > > > enables
> > > > > > > > > > > > > > more
> > > > > > > > > > > > > > > > > fine-grained metrics like the ones proposed
> > in
> > > > > > KIP-767
> > > > > > > > [2].
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > [1] -
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://github.com/apache/kafka/blob/9ab140d5419d735baae45aff56ffce7f5622744f/connect/runtime/src/main/java/org/apache/kafka/connect/runtime/SubmittedRecords.java
> > > > > > > > > > > > > > > > > [2] -
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-767%3A+Connect+Latency+Metrics
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Cheers,
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Chris
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > On Tue, Nov 1, 2022 at 11:21 AM Yash Mayya
> <
> > > > > > > > > > > yash.mayya@gmail.com
> > > > > > > > > > > > >
> > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > Hi Randall,
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > It's been a while for this one but the
> > more I
> > > > > think
> > > > > > > > about
> > > > > > > > > > it,
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > more
> > > > > > > > > > > > > > > > I
> > > > > > > > > > > > > > > > > > feel like the current approach with a new
> > > > > > overloaded
> > > > > > > > > > > > > > `SinkTask::put`
> > > > > > > > > > > > > > > > > method
> > > > > > > > > > > > > > > > > > might not be optimal. We're trying to
> fix a
> > > > > pretty
> > > > > > > > corner
> > > > > > > > > > > case
> > > > > > > > > > > > > bug
> > > > > > > > > > > > > > > here
> > > > > > > > > > > > > > > > > > (usage of topic mutating SMTs with sink
> > > > > connectors
> > > > > > > that
> > > > > > > > > do
> > > > > > > > > > > > their
> > > > > > > > > > > > > > own
> > > > > > > > > > > > > > > > > offset
> > > > > > > > > > > > > > > > > > tracking) and I'm not sure that warrants
> a
> > > > change
> > > > > > to
> > > > > > > > > such a
> > > > > > > > > > > > > central
> > > > > > > > > > > > > > > > > > interface method. The new `SinkTask::put`
> > > > method
> > > > > > just
> > > > > > > > > seems
> > > > > > > > > > > > > > somewhat
> > > > > > > > > > > > > > > > odd
> > > > > > > > > > > > > > > > > > and it may not be very understandable
> for a
> > > new
> > > > > > > reader
> > > > > > > > -
> > > > > > > > > I
> > > > > > > > > > > > don't
> > > > > > > > > > > > > > > think
> > > > > > > > > > > > > > > > > this
> > > > > > > > > > > > > > > > > > should be the case for a public interface
> > > > method.
> > > > > > > > > > > Furthermore,
> > > > > > > > > > > > > even
> > > > > > > > > > > > > > > > with
> > > > > > > > > > > > > > > > > > elaborate documentation in place, I'm not
> > > sure
> > > > if
> > > > > > > it'll
> > > > > > > > > be
> > > > > > > > > > > very
> > > > > > > > > > > > > > > obvious
> > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > most people what the purpose of having
> > these
> > > > two
> > > > > > > `put`
> > > > > > > > > > > methods
> > > > > > > > > > > > is
> > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > how
> > > > > > > > > > > > > > > > > > they should be used by sink task
> > > > implementations.
> > > > > > > What
> > > > > > > > do
> > > > > > > > > > you
> > > > > > > > > > > > > > think?
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > > > Yash
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > On Mon, Oct 10, 2022 at 9:33 PM Yash
> Mayya
> > <
> > > > > > > > > > > > yash.mayya@gmail.com
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Hi Randall,
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Thanks a lot for your valuable feedback
> > so
> > > > far!
> > > > > > > I've
> > > > > > > > > > > updated
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > KIP
> > > > > > > > > > > > > > > > > > based
> > > > > > > > > > > > > > > > > > > on our discussion above. Could you
> please
> > > > take
> > > > > > > > another
> > > > > > > > > > > look?
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > > > > Yash
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > > On Tue, Oct 4, 2022 at 12:40 AM Randall
> > > > Hauch <
> > > > > > > > > > > > > rhauch@gmail.com>
> > > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >> On Mon, Oct 3, 2022 at 11:45 AM Yash
> > > Mayya <
> > > > > > > > > > > > > > yash.mayya@gmail.com>
> > > > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >> > Hi Randall,
> > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > >> > Thanks for elaborating. I think
> these
> > > are
> > > > > all
> > > > > > > very
> > > > > > > > > > good
> > > > > > > > > > > > > points
> > > > > > > > > > > > > > > > and I
> > > > > > > > > > > > > > > > > > see
> > > > > > > > > > > > > > > > > > >> > why the overloaded `SinkTask::put`
> > > method
> > > > > is a
> > > > > > > > > cleaner
> > > > > > > > > > > > > > solution
> > > > > > > > > > > > > > > > > > overall.
> > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > >> > > public void
> > put(Collection<SinkRecord>
> > > > > > > records,
> > > > > > > > > > > > > > > Map<SinkRecord,
> > > > > > > > > > > > > > > > > > >> > TopicPartition>
> > updatedTopicPartitions)
> > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > >> > I think this should be
> > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > >> > `public void
> > put(Collection<SinkRecord>
> > > > > > records,
> > > > > > > > > > > > > > Map<SinkRecord,
> > > > > > > > > > > > > > > > > > >> > TopicPartition>
> > > originalTopicPartitions)`
> > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > >> > instead because the sink records
> > > > themselves
> > > > > > have
> > > > > > > > the
> > > > > > > > > > > > updated
> > > > > > > > > > > > > > > topic
> > > > > > > > > > > > > > > > > > >> > partitions (i.e. after all
> > > transformations
> > > > > > have
> > > > > > > > been
> > > > > > > > > > > > > applied)
> > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > >> KIP
> > > > > > > > > > > > > > > > > > >> > is proposing a way for the tasks to
> be
> > > > able
> > > > > to
> > > > > > > > > access
> > > > > > > > > > > the
> > > > > > > > > > > > > > > original
> > > > > > > > > > > > > > > > > > topic
> > > > > > > > > > > > > > > > > > >> > partition (i.e. before
> transformations
> > > > have
> > > > > > been
> > > > > > > > > > > applied).
> > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >> Sounds good.
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > >> > > Of course, if the developer does
> not
> > > > need
> > > > > > > > separate
> > > > > > > > > > > > > methods,
> > > > > > > > > > > > > > > they
> > > > > > > > > > > > > > > > > can
> > > > > > > > > > > > > > > > > > >> > easily have the older `put` method
> > > simply
> > > > > > > delegate
> > > > > > > > > to
> > > > > > > > > > > the
> > > > > > > > > > > > > > newer
> > > > > > > > > > > > > > > > > > method.
> > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > >> > If the developer does not need
> > separate
> > > > > > methods
> > > > > > > > > (i.e.
> > > > > > > > > > > they
> > > > > > > > > > > > > > don't
> > > > > > > > > > > > > > > > > need
> > > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > >> > use this new addition), they can
> > simply
> > > > > > continue
> > > > > > > > > > > > > implementing
> > > > > > > > > > > > > > > just
> > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > >> > older `put` method right?
> > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >> Correct. We should update the JavaDoc
> of
> > > > both
> > > > > > > > methods
> > > > > > > > > to
> > > > > > > > > > > > make
> > > > > > > > > > > > > > this
> > > > > > > > > > > > > > > > > > clear,
> > > > > > > > > > > > > > > > > > >> and in general how the two methods
> > should
> > > > are
> > > > > > used
> > > > > > > > and
> > > > > > > > > > > > should
> > > > > > > > > > > > > be
> > > > > > > > > > > > > > > > > > >> implemented. That can be part of the
> PR,
> > > and
> > > > > the
> > > > > > > KIP
> > > > > > > > > > > doesn't
> > > > > > > > > > > > > > need
> > > > > > > > > > > > > > > > this
> > > > > > > > > > > > > > > > > > >> wording.
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > >> > > Finally, this gives us a roadmap
> for
> > > > > > > > *eventually*
> > > > > > > > > > > > > > deprecating
> > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > >> older
> > > > > > > > > > > > > > > > > > >> > method, once the Connect runtime
> > > versions
> > > > > > > without
> > > > > > > > > this
> > > > > > > > > > > > > change
> > > > > > > > > > > > > > > are
> > > > > > > > > > > > > > > > > old
> > > > > > > > > > > > > > > > > > >> > enough.
> > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > >> > I'm not sure we'd ever want to
> > deprecate
> > > > the
> > > > > > > older
> > > > > > > > > > > method.
> > > > > > > > > > > > > > Most
> > > > > > > > > > > > > > > > > common
> > > > > > > > > > > > > > > > > > >> sink
> > > > > > > > > > > > > > > > > > >> > connector implementations do not do
> > > their
> > > > > own
> > > > > > > > offset
> > > > > > > > > > > > > tracking
> > > > > > > > > > > > > > > with
> > > > > > > > > > > > > > > > > > >> > asynchronous processing and will
> > > probably
> > > > > > never
> > > > > > > > > have a
> > > > > > > > > > > > need
> > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > >> > additional parameter
> `Map<SinkRecord,
> > > > > > > > > TopicPartition>
> > > > > > > > > > > > > > > > > > >> > originalTopicPartitions` in the
> > proposed
> > > > new
> > > > > > > `put`
> > > > > > > > > > > method.
> > > > > > > > > > > > > > These
> > > > > > > > > > > > > > > > > > >> connectors
> > > > > > > > > > > > > > > > > > >> > can continue implementing only the
> > > > existing
> > > > > > > > > > > > `SinkTask::put`
> > > > > > > > > > > > > > > method
> > > > > > > > > > > > > > > > > > which
> > > > > > > > > > > > > > > > > > >> > will be called by the default
> > > > implementation
> > > > > > of
> > > > > > > > the
> > > > > > > > > > > newer
> > > > > > > > > > > > > > > > overloaded
> > > > > > > > > > > > > > > > > > >> `put`
> > > > > > > > > > > > > > > > > > >> > method.
> > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >> +1
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > >> > > the pre-commit methods use the
> same
> > > > > > > > > > > `Map<TopicPartition,
> > > > > > > > > > > > > > > > > > >> > OffsetAndMetadata> currentOffsets`
> > data
> > > > > > > structure
> > > > > > > > > I'm
> > > > > > > > > > > > > > suggesting
> > > > > > > > > > > > > > > > be
> > > > > > > > > > > > > > > > > > >> used.
> > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > >> > The data structure you're suggesting
> > be
> > > > used
> > > > > > is
> > > > > > > a
> > > > > > > > > > > > > > > `Map<SinkRecord,
> > > > > > > > > > > > > > > > > > >> > TopicPartition>` which will map
> > > > `SinkRecord`
> > > > > > > > objects
> > > > > > > > > > to
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > > original
> > > > > > > > > > > > > > > > > > >> topic
> > > > > > > > > > > > > > > > > > >> > partition of the corresponding
> > > > > > `ConsumerRecord`
> > > > > > > > > right?
> > > > > > > > > > > To
> > > > > > > > > > > > > > > clarify,
> > > > > > > > > > > > > > > > > > this
> > > > > > > > > > > > > > > > > > >> is
> > > > > > > > > > > > > > > > > > >> > a new data structure that will need
> to
> > > be
> > > > > > > managed
> > > > > > > > in
> > > > > > > > > > the
> > > > > > > > > > > > > > > > > > >> `WorkerSinkTask`.
> > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >> Ah, you're right. Thanks for the
> > > correction.
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >> Best regards,
> > > > > > > > > > > > > > > > > > >> Randall
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >> > Thanks,
> > > > > > > > > > > > > > > > > > >> > Yash
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >> > On Mon, Oct 3, 2022 at 1:20 AM
> Randall
> > > > > Hauch <
> > > > > > > > > > > > > > rhauch@gmail.com>
> > > > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > >> > > Hi, Yash.
> > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > >> > > I'm not sure I quite understand
> why
> > it
> > > > > would
> > > > > > > be
> > > > > > > > > > > "easier"
> > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > > > connector
> > > > > > > > > > > > > > > > > > >> > > > developers to account for
> > > implementing
> > > > > two
> > > > > > > > > > different
> > > > > > > > > > > > > > > > overloaded
> > > > > > > > > > > > > > > > > > >> `put`
> > > > > > > > > > > > > > > > > > >> > > > methods (assuming that they want
> > to
> > > > use
> > > > > > this
> > > > > > > > new
> > > > > > > > > > > > > feature)
> > > > > > > > > > > > > > > > versus
> > > > > > > > > > > > > > > > > > >> using
> > > > > > > > > > > > > > > > > > >> > a
> > > > > > > > > > > > > > > > > > >> > > > try-catch block around
> > `SinkRecord`
> > > > > access
> > > > > > > > > > methods?
> > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > >> > > Using a try-catch to try around an
> > API
> > > > > > method
> > > > > > > > that
> > > > > > > > > > > > *might*
> > > > > > > > > > > > > > be
> > > > > > > > > > > > > > > > > there
> > > > > > > > > > > > > > > > > > >> is a
> > > > > > > > > > > > > > > > > > >> > > very unusual thing for most
> > > developers.
> > > > > > > > > > Unfortunately,
> > > > > > > > > > > > > we've
> > > > > > > > > > > > > > > had
> > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > >> > resort
> > > > > > > > > > > > > > > > > > >> > > to this atypical approach with
> > Connect
> > > > in
> > > > > > > places
> > > > > > > > > > when
> > > > > > > > > > > > > there
> > > > > > > > > > > > > > > was
> > > > > > > > > > > > > > > > no
> > > > > > > > > > > > > > > > > > >> good
> > > > > > > > > > > > > > > > > > >> > > alternative. We seem to relying
> upon
> > > > > pattern
> > > > > > > > > because
> > > > > > > > > > > > it's
> > > > > > > > > > > > > > > easier
> > > > > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > > > >> us,
> > > > > > > > > > > > > > > > > > >> > > not because it offers a better
> > > > experience
> > > > > > for
> > > > > > > > > > > Connector
> > > > > > > > > > > > > > > > > developers.
> > > > > > > > > > > > > > > > > > >> IMO,
> > > > > > > > > > > > > > > > > > >> > if
> > > > > > > > > > > > > > > > > > >> > > there's a practical alternative
> that
> > > > uses
> > > > > > > normal
> > > > > > > > > > > > > development
> > > > > > > > > > > > > > > > > > practices
> > > > > > > > > > > > > > > > > > >> > and
> > > > > > > > > > > > > > > > > > >> > > techniques, then we should use
> that
> > > > > > > alternative.
> > > > > > > > > > IIUC,
> > > > > > > > > > > > > there
> > > > > > > > > > > > > > > is
> > > > > > > > > > > > > > > > at
> > > > > > > > > > > > > > > > > > >> least
> > > > > > > > > > > > > > > > > > >> > > one practical alternative for this
> > KIP
> > > > > that
> > > > > > > > would
> > > > > > > > > > not
> > > > > > > > > > > > > > require
> > > > > > > > > > > > > > > > > > >> developers
> > > > > > > > > > > > > > > > > > >> > to
> > > > > > > > > > > > > > > > > > >> > > use the unusual try-catch to
> handle
> > > the
> > > > > case
> > > > > > > > where
> > > > > > > > > > > > methods
> > > > > > > > > > > > > > are
> > > > > > > > > > > > > > > > not
> > > > > > > > > > > > > > > > > > >> found.
> > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > >> > > I also think having two `put`
> > methods
> > > is
> > > > > > > easier
> > > > > > > > > when
> > > > > > > > > > > the
> > > > > > > > > > > > > > > > Connector
> > > > > > > > > > > > > > > > > > >> has to
> > > > > > > > > > > > > > > > > > >> > > do different things for different
> > > > Connect
> > > > > > > > > runtimes,
> > > > > > > > > > > too.
> > > > > > > > > > > > > One
> > > > > > > > > > > > > > > of
> > > > > > > > > > > > > > > > > > those
> > > > > > > > > > > > > > > > > > >> > > methods is called by newer Connect
> > > > > runtimes
> > > > > > > with
> > > > > > > > > the
> > > > > > > > > > > new
> > > > > > > > > > > > > > > > behavior,
> > > > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > >> > the
> > > > > > > > > > > > > > > > > > >> > > other method is called by an older
> > > > Connect
> > > > > > > > > runtime.
> > > > > > > > > > Of
> > > > > > > > > > > > > > course,
> > > > > > > > > > > > > > > > if
> > > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > >> > > developer does not need separate
> > > > methods,
> > > > > > they
> > > > > > > > can
> > > > > > > > > > > > easily
> > > > > > > > > > > > > > have
> > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > >> older
> > > > > > > > > > > > > > > > > > >> > > `put` method simply delegate to
> the
> > > > newer
> > > > > > > > method.
> > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > >> > > Finally, this gives us a roadmap
> for
> > > > > > > > *eventually*
> > > > > > > > > > > > > > deprecating
> > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > >> older
> > > > > > > > > > > > > > > > > > >> > > method, once the Connect runtime
> > > > versions
> > > > > > > > without
> > > > > > > > > > this
> > > > > > > > > > > > > > change
> > > > > > > > > > > > > > > > are
> > > > > > > > > > > > > > > > > > old
> > > > > > > > > > > > > > > > > > >> > > enough.
> > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > >> > > I think the advantage of going
> with
> > > the
> > > > > > > > > > > > > > > > > > >> > > > proposed approach in the KIP is
> > that
> > > > it
> > > > > > > > wouldn't
> > > > > > > > > > > > require
> > > > > > > > > > > > > > > extra
> > > > > > > > > > > > > > > > > > >> > > book-keeping
> > > > > > > > > > > > > > > > > > >> > > > (the Map<SinkRecord,
> > > > > > > > > > > > > > > > > > >> > > > TopicPartition> in
> > `WorkerSinkTask`
> > > in
> > > > > > your
> > > > > > > > > > proposed
> > > > > > > > > > > > > > > approach)
> > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > >> > > The connector does have to do some
> > of
> > > > this
> > > > > > > > > > bookkeeping
> > > > > > > > > > > > in
> > > > > > > > > > > > > > how
> > > > > > > > > > > > > > > > they
> > > > > > > > > > > > > > > > > > >> track
> > > > > > > > > > > > > > > > > > >> > > the topic partition offsets used
> in
> > > the
> > > > > > > > > `preCommit`,
> > > > > > > > > > > and
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > >> pre-commit
> > > > > > > > > > > > > > > > > > >> > > methods use the same
> > > > `Map<TopicPartition,
> > > > > > > > > > > > > OffsetAndMetadata>
> > > > > > > > > > > > > > > > > > >> > > currentOffsets`
> > > > > > > > > > > > > > > > > > >> > > data structure I'm suggesting be
> > used.
> > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > >> > > I hope that helps.
> > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > >> > > Best regards,
> > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > >> > > Randall
> > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > >> > > On Mon, Sep 26, 2022 at 9:38 AM
> Yash
> > > > > Mayya <
> > > > > > > > > > > > > > > > yash.mayya@gmail.com>
> > > > > > > > > > > > > > > > > > >> wrote:
> > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > >> > > > Hi Randall,
> > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > >> > > > Thanks for reviewing the KIP!
> > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > >> > > > > That latter logic can get
> quite
> > > > ugly.
> > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > >> > > > I'm not sure I quite understand
> > why
> > > it
> > > > > > would
> > > > > > > > be
> > > > > > > > > > > > "easier"
> > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > > > >> connector
> > > > > > > > > > > > > > > > > > >> > > > developers to account for
> > > implementing
> > > > > two
> > > > > > > > > > different
> > > > > > > > > > > > > > > > overloaded
> > > > > > > > > > > > > > > > > > >> `put`
> > > > > > > > > > > > > > > > > > >> > > > methods (assuming that they want
> > to
> > > > use
> > > > > > this
> > > > > > > > new
> > > > > > > > > > > > > feature)
> > > > > > > > > > > > > > > > versus
> > > > > > > > > > > > > > > > > > >> using
> > > > > > > > > > > > > > > > > > >> > a
> > > > > > > > > > > > > > > > > > >> > > > try-catch block around
> > `SinkRecord`
> > > > > access
> > > > > > > > > > methods?
> > > > > > > > > > > In
> > > > > > > > > > > > > > both
> > > > > > > > > > > > > > > > > > cases, a
> > > > > > > > > > > > > > > > > > >> > > > connector developer would need
> to
> > > > write
> > > > > > > > > additional
> > > > > > > > > > > > code
> > > > > > > > > > > > > in
> > > > > > > > > > > > > > > > order
> > > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > > >> > > ensure
> > > > > > > > > > > > > > > > > > >> > > > that their connector continues
> > > working
> > > > > > with
> > > > > > > > > older
> > > > > > > > > > > > > Connect
> > > > > > > > > > > > > > > > > > runtimes.
> > > > > > > > > > > > > > > > > > >> > > > Furthermore, we would probably
> > need
> > > to
> > > > > > > > carefully
> > > > > > > > > > > > > document
> > > > > > > > > > > > > > > how
> > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > > >> > > > implementation for the older
> `put`
> > > > > method
> > > > > > > > should
> > > > > > > > > > > look
> > > > > > > > > > > > > like
> > > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > > > >> > connectors
> > > > > > > > > > > > > > > > > > >> > > > that want to use this new
> > feature. I
> > > > > think
> > > > > > > the
> > > > > > > > > > > > advantage
> > > > > > > > > > > > > > of
> > > > > > > > > > > > > > > > > going
> > > > > > > > > > > > > > > > > > >> with
> > > > > > > > > > > > > > > > > > >> > > the
> > > > > > > > > > > > > > > > > > >> > > > proposed approach in the KIP is
> > that
> > > > it
> > > > > > > > wouldn't
> > > > > > > > > > > > require
> > > > > > > > > > > > > > > extra
> > > > > > > > > > > > > > > > > > >> > > book-keeping
> > > > > > > > > > > > > > > > > > >> > > > (the Map<SinkRecord,
> > > > > > > > > > > > > > > > > > >> > > > TopicPartition> in
> > `WorkerSinkTask`
> > > in
> > > > > > your
> > > > > > > > > > proposed
> > > > > > > > > > > > > > > approach)
> > > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > >> also
> > > > > > > > > > > > > > > > > > >> > > the
> > > > > > > > > > > > > > > > > > >> > > > fact that the try-catch based
> > logic
> > > is
> > > > > an
> > > > > > > > > already
> > > > > > > > > > > > > > > established
> > > > > > > > > > > > > > > > > > >> pattern
> > > > > > > > > > > > > > > > > > >> > > > through
> > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-610%3A+Error+Reporting+in+Sink+Connectors
> > > > > > > > > > > > > > > > > > >> > > > and other KIPs which added
> methods
> > > to
> > > > > > > > > source/sink
> > > > > > > > > > > > > > > > connector/task
> > > > > > > > > > > > > > > > > > >> > > contexts.
> > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > >> > > > Let me know if you still feel
> that
> > > > > having
> > > > > > a
> > > > > > > > new
> > > > > > > > > > > > > overloaded
> > > > > > > > > > > > > > > put
> > > > > > > > > > > > > > > > > > >> method
> > > > > > > > > > > > > > > > > > >> > is
> > > > > > > > > > > > > > > > > > >> > > a
> > > > > > > > > > > > > > > > > > >> > > > cleaner solution and I'd be
> happy
> > to
> > > > > > > > reconsider!
> > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > >> > > > Thanks,
> > > > > > > > > > > > > > > > > > >> > > > Yash
> > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > >> > > > On Thu, Sep 22, 2022 at 11:18 PM
> > > > Randall
> > > > > > > > Hauch <
> > > > > > > > > > > > > > > > > rhauch@gmail.com>
> > > > > > > > > > > > > > > > > > >> > wrote:
> > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > >> > > > > Hi, Yash. Thanks for picking
> up
> > > this
> > > > > KIP
> > > > > > > and
> > > > > > > > > > > > > discussion.
> > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > >> > > > > The KIP includes this rejected
> > > > > > > alternative:
> > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > >> > > > > > 4. Update SinkTask.put in
> any
> > > way
> > > > to
> > > > > > > pass
> > > > > > > > > the
> > > > > > > > > > > new
> > > > > > > > > > > > > > > > > information
> > > > > > > > > > > > > > > > > > >> > outside
> > > > > > > > > > > > > > > > > > >> > > > > > SinkRecord (e.g. a Map or a
> > > > derived
> > > > > > > class)
> > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > >> > > > > >    -
> > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > >> > > > > >    Much more disruptive
> change
> > > > > without
> > > > > > > > > > > > considerable
> > > > > > > > > > > > > > pros
> > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > >> > > > > One advantage about doing this
> > is
> > > > that
> > > > > > > sink
> > > > > > > > > > > > connector
> > > > > > > > > > > > > > > > > > >> implementations
> > > > > > > > > > > > > > > > > > >> > > can
> > > > > > > > > > > > > > > > > > >> > > > > more easily implement two
> > > different
> > > > > > > > "put(...)"
> > > > > > > > > > > > methods
> > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > handle
> > > > > > > > > > > > > > > > > > >> > > running
> > > > > > > > > > > > > > > > > > >> > > > in
> > > > > > > > > > > > > > > > > > >> > > > > a variety of runtimes, without
> > > > having
> > > > > to
> > > > > > > use
> > > > > > > > > > > > try-catch
> > > > > > > > > > > > > > > logic
> > > > > > > > > > > > > > > > > > >> around
> > > > > > > > > > > > > > > > > > >> > the
> > > > > > > > > > > > > > > > > > >> > > > > newer SinkRecord access
> methods.
> > > > That
> > > > > > > latter
> > > > > > > > > > logic
> > > > > > > > > > > > can
> > > > > > > > > > > > > > get
> > > > > > > > > > > > > > > > > quite
> > > > > > > > > > > > > > > > > > >> > ugly.
> > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > >> > > > > For example, the existing
> `put`
> > > > method
> > > > > > has
> > > > > > > > > this
> > > > > > > > > > > > > > signature:
> > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > >> > > > > public abstract void
> > > > > > > > > put(Collection<SinkRecord>
> > > > > > > > > > > > > > records);
> > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > >> > > > > If we added an overloaded
> method
> > > > that
> > > > > > > passed
> > > > > > > > > in
> > > > > > > > > > a
> > > > > > > > > > > > map
> > > > > > > > > > > > > of
> > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > old
> > > > > > > > > > > > > > > > > > >> > > > > topic+partition for each
> record
> > > (and
> > > > > > > defined
> > > > > > > > > the
> > > > > > > > > > > > > absence
> > > > > > > > > > > > > > > of
> > > > > > > > > > > > > > > > an
> > > > > > > > > > > > > > > > > > >> entry
> > > > > > > > > > > > > > > > > > >> > as
> > > > > > > > > > > > > > > > > > >> > > > > having an unchanged topic and
> > > > > > partition):
> > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > >> > > > > public void
> > > > put(Collection<SinkRecord>
> > > > > > > > > records,
> > > > > > > > > > > > > > > > > Map<SinkRecord,
> > > > > > > > > > > > > > > > > > >> > > > > TopicPartition>
> > > > > updatedTopicPartitions)
> > > > > > {
> > > > > > > > > > > > > > > > > > >> > > > > put(records);
> > > > > > > > > > > > > > > > > > >> > > > > }
> > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > >> > > > > then a `SinkTask`
> implementation
> > > > that
> > > > > > > wants
> > > > > > > > to
> > > > > > > > > > use
> > > > > > > > > > > > > this
> > > > > > > > > > > > > > > new
> > > > > > > > > > > > > > > > > > >> feature
> > > > > > > > > > > > > > > > > > >> > > could
> > > > > > > > > > > > > > > > > > >> > > > > simply implement both methods:
> > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > >> > > > > public void
> > > > put(Collection<SinkRecord>
> > > > > > > > > records)
> > > > > > > > > > {
> > > > > > > > > > > > > > > > > > >> > > > > // Running in an older
> runtime,
> > so
> > > > no
> > > > > > > > tracking
> > > > > > > > > > of
> > > > > > > > > > > > > > > > SMT-modified
> > > > > > > > > > > > > > > > > > >> topic
> > > > > > > > > > > > > > > > > > >> > > > names
> > > > > > > > > > > > > > > > > > >> > > > > or partitions
> > > > > > > > > > > > > > > > > > >> > > > > put(records, Map.of());
> > > > > > > > > > > > > > > > > > >> > > > > }
> > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > >> > > > > public void
> > > > put(Collection<SinkRecord>
> > > > > > > > > records,
> > > > > > > > > > > > > > > > > Map<SinkRecord,
> > > > > > > > > > > > > > > > > > >> > > > > TopicPartition>
> > > > > updatedTopicPartitions)
> > > > > > {
> > > > > > > > > > > > > > > > > > >> > > > > // real logic here
> > > > > > > > > > > > > > > > > > >> > > > > }
> > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > >> > > > > This seems a lot easier than
> > > having
> > > > to
> > > > > > use
> > > > > > > > > > > try-catch
> > > > > > > > > > > > > > > logic,
> > > > > > > > > > > > > > > > > yet
> > > > > > > > > > > > > > > > > > >> still
> > > > > > > > > > > > > > > > > > >> > > > > allows sink connectors to
> > utilize
> > > > the
> > > > > > new
> > > > > > > > > > > > > functionality
> > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > > still
> > > > > > > > > > > > > > > > > > >> > work
> > > > > > > > > > > > > > > > > > >> > > > with
> > > > > > > > > > > > > > > > > > >> > > > > older Connect runtimes.
> > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > >> > > > > WDYT?
> > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > >> > > > > Randall
> > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > >> > > > > On Thu, Sep 8, 2022 at 7:03 AM
> > > Yash
> > > > > > Mayya
> > > > > > > <
> > > > > > > > > > > > > > > > > yash.mayya@gmail.com
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > >> > > wrote:
> > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > >> > > > > > Hi all,
> > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > >> > > > > > I would like to (re)start a
> > new
> > > > > > > discussion
> > > > > > > > > > > thread
> > > > > > > > > > > > on
> > > > > > > > > > > > > > > > KIP-793
> > > > > > > > > > > > > > > > > > >> (Kafka
> > > > > > > > > > > > > > > > > > >> > > > > > Connect) which proposes some
> > > > > additions
> > > > > > > to
> > > > > > > > > the
> > > > > > > > > > > > public
> > > > > > > > > > > > > > > > > > SinkRecord
> > > > > > > > > > > > > > > > > > >> > > > interface
> > > > > > > > > > > > > > > > > > >> > > > > > in order to support topic
> > > mutating
> > > > > > SMTs
> > > > > > > > for
> > > > > > > > > > sink
> > > > > > > > > > > > > > > > connectors
> > > > > > > > > > > > > > > > > > >> that do
> > > > > > > > > > > > > > > > > > >> > > > their
> > > > > > > > > > > > > > > > > > >> > > > > > own offset tracking.
> > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > >> > > > > > Links:
> > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > >> > > > > > KIP:
> > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=191336830
> > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > >> > > > > > Older discussion thread:
> > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > >
> > > > > > > >
> > https://lists.apache.org/thread/00kcth6057jdcsyzgy1x8nb2s1cymy8h
> > > > > > > > > ,
> > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > >
> > > > > > > >
> > https://lists.apache.org/thread/rzqkm0q5y5v3vdjhg8wqppxbkw7nyopj
> > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > >> > > > > > Jira:
> > > > > > > > > > > > > >
> https://issues.apache.org/jira/browse/KAFKA-13431
> > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > >> > > > > > Thanks,
> > > > > > > > > > > > > > > > > > >> > > > > > Yash
> > > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
>

Re: [DISCUSS] KIP-793: Sink Connectors: Support topic-mutating SMTs for async connectors (preCommit users)

[Yash Mayya <ya...@gmail.com>]

Hi Greg,

Thanks for the response and sorry for the late reply.

> Currently the AK tests have a lot of calls to, for example, new
> SinkRecord(String topic, int partition, Schema keySchema,
> Object key, Schema valueSchema, Object value, long kafkaOffset)
> , a constructor without the original T/P/O values. I assumed that for
> backwards compatibility these constructors would still be usable in
> new runtimes. I imagine that there are also tests in downstream projects
> which make use of these constructors, whenever a Transform, Predicate,
> or Task is tested without a corresponding Converter. My question was
> about what values are chosen for the original T/P/O methods when these
> constructors are used after an upgrade to the latest connect-api.

That's a good question - since this should only primarily affect testing I
think it should be acceptable to simply use the topic, partition and
kafkaOffset values as the originalTopic, originalKafkaPartition
and originalKafkaOffset?

> If you inject the original T/P/O only before and after the chain, SMTs
> after an SMT which changes the original T/P/O will see whatever the
earlier
> SMT emitted. Is this intentional, or should this be avoided?

Hmm, this sounds like a misbehaving / badly implemented SMTs since there
doesn't seem to be any reasonable situation where an SMT should modify a
sink record's original topic / partition / offset data so I'm not in favor
of introducing checks and guards in the framework for this.

Another point that I've been pondering about is the one you raised about
the composability of Connect's plugin ecosystem and the special case
handling we're adding to sink connector plugins to work with certain
transformation plugin types. This really doesn't seem like a good precedent
to be setting / starting (since there don't seem to be any other such
"snowflake" inter-plugin interactions) in my opinion. The alternative of
completely managing this in the framework (and only exposing the virtual
coordinates to the sink tasks) doesn't seem too appealing either due to the
backward compatibility concerns while maintaining existing support and
functionality such as the possibility of implementing exactly-once
semantics, ability for tasks to rewind consumer offsets arbitrarily (which
might require the introduction of some form of persistence for the physical
<-> virtual coordinate mapping) etc. Unfortunately, even though this is a
long standing problem that all of us want to fix, I'm considering moving
this KIP into a dormant / inactive state since there doesn't seem to be a
design that satisfies all the general principles that the Kafka Connect
framework has striven to uphold.

Thanks,
Yash

On Tue, Mar 14, 2023 at 3:31 AM Greg Harris <gr...@aiven.io.invalid>
wrote:

> Yash,
>
> > 'm not sure I follow - are you asking about how the tests will be updated
> post this change or about how upgrades will look like for clusters in
> production?
>
> Currently the AK tests have a lot of calls to, for example, new
> SinkRecord(String topic, int partition, Schema keySchema, Object key,
> Schema valueSchema, Object value, long kafkaOffset), a constructor without
> the original T/P/O values. I assumed that for backwards compatibility these
> constructors would still be usable in new runtimes.
> I imagine that there are also tests in downstream projects which make use
> of these constructors, whenever a Transform, Predicate, or Task is tested
> without a corresponding Converter. My question was about what values are
> chosen for the original T/P/O methods when these constructors are used
> after an upgrade to the latest connect-api.
>
> > There shouldn't be any difference in behavior here - the framework will
> add
> the original T/P/O metadata to the record after the entire transformation
> chain has been applied and just before sending the record to the task for
> processing. The KIP doesn't propose that transformations themselves should
> also be able to retrieve original T/P/O information for a sink record.
>
> The KIP includes this: "Note that while the record's offset can't be
> modified via the standard SinkRecord::newRecord methods that SMTs are
> expected to use, SinkRecord has public constructors that would allow SMTs
> to return records with modified offsets. This is why the proposed changes
> include a new SinkRecord::originalKafkaOffset method as well."
> In order to use the new or old SinkRecord constructors outside of the
> newRecord methods, SMTs will downcast the previous record and may access
> the original T/P/O methods. They may or may not forward this to the next
> SMT, and they may or may not use it in their own computation.
> Since this is acknowledged as a possible implementation, I was just asking
> about when one SMT changes the original T/P/O, what should later SMTs and
> predicates see from the original T/P/O methods?
> If you inject the original T/P/O only before and after the chain, SMTs
> after an SMT which changes the original T/P/O will see whatever the earlier
> SMT emitted. Is this intentional, or should this be avoided?
> For existing SMTs use the SinkRecord constructor, either directly or via
> subclasses of ConnectRecord, they will drop the original T/P/O and fall
> back to the logic from question (1).
>
> > The rejected alternative basically says that we can't do a
> deterministic mapping from virtual coordinates to physical coordinates
> without doing a lot of book-keeping.
>
> I suppose there is a possible implementation of metadata book-keeping which
> provides a reasonable system of virtual coordinates, it just ended up
> equivalent to hydrating intermediate topics to compute a consistent record
> ordering. I wasn't convinced by calling it "book-keeping" since i've seen
> that phrase used to disregard much less complicated state management, and
> had to see exactly where that solution becomes unreasonable.
>
> Thanks,
> Greg
>
> On Sun, Mar 12, 2023 at 6:30 AM Yash Mayya <ya...@gmail.com> wrote:
>
> > Hi Greg,
> >
> > Thanks for the detailed review!
> >
> > > What is the expected state/behavior for SinkRecords
> > > which do not have original T/P/O information after the
> > > upgrade? Just browsing, it appears that tests make
> > > extensive use of the existing public SinkRecord
> > > constructors  for both Transformations and Connectors.
> >
> > I'm not sure I follow - are you asking about how the tests will be
> updated
> > post this change or about how upgrades will look like for clusters in
> > production? For the latter, we won't have to worry about sink records
> > without original T/P/O information at all once a cluster is fully rolled
> > and we will make it (hopefully) abundantly clear that connectors need to
> > account for missing original T/P/O getter methods if they expect to be
> > deployed on older Connect runtimes.
> >
> > > What is the expected behavior for Transformation
> > > implementations which do not use the newRecord
> > > methods and instead use public SinkRecord constructors?
> > > The KIP mentions this as a justification for the
> > > originalKafkaOffset method, but if existing implementations
> > > are using the existing constructors, those constructors won't
> > > forward the original T/P/O information to later transforms or
> > > the task.
> >
> > There shouldn't be any difference in behavior here - the framework will
> add
> > the original T/P/O metadata to the record after the entire transformation
> > chain has been applied and just before sending the record to the task for
> > processing. The KIP doesn't propose that transformations themselves
> should
> > also be able to retrieve original T/P/O information for a sink record.
> >
> > > This reasoning and the KIP design seems to imply that the
> > > connector is better equipped to solve this problem than the
> > > framework, but the stated reasons are not convincing for me.
> >
> > This was added to the KIP by the original author, but I don't think the
> > intention was to imply that the connector is better equipped to solve
> this
> > problem than the framework. The intention is to provide complete
> > information to the connector ("physical" and "virtual coordinates"
> instead
> > of the currently incomplete "virtual coordinates" as you've termed it) so
> > that connectors can use the virtual coordinates for writing data to the
> > sink system and physical coordinates for offset reporting back to the
> > framework. The rejected alternative basically says that we can't do a
> > deterministic mapping from virtual coordinates to physical coordinates
> > without doing a lot of book-keeping.
> >
> > I agree with the rest of your analysis on the tradeoffs between the
> > proposed approach versus the seemingly more attractive approach of
> handling
> > everything purely in the framework and only exposing "virtual
> coordinates"
> > to the connectors. I think the biggest thorn here is maintaining backward
> > compatibility with the considerable ecosystem of existing connectors
> which
> > is something Connect has always been burdened by.
> >
> > Thanks,
> > Yash
> >
> > On Wed, Mar 8, 2023 at 6:54 AM Greg Harris <greg.harris@aiven.io.invalid
> >
> > wrote:
> >
> > > Hi Yash,
> > >
> > > I always use this issue as an example of a bug being caused by design
> > > rather than by implementation error, and once it's fixed I'll need to
> > find
> > > something else to talk about :)
> > > So glad to see this get fixed!
> > >
> > > I'll chime in to support some of the earlier discussions that seem to
> > have
> > > been resolved:
> > >
> > > 1. With respect to SinkRecord methods vs an overloaded put(): I agree
> > with
> > > the current design but I justify it a little bit differently than has
> > > already been discussed.
> > > If we were designing this interface on day 1 without backwards
> > > compatibility in mind, which design would make more sense? Or for a
> > > different framing: In the future when old runtimes and connectors are
> > > retired and the old interfaces are removed, which design is going to
> look
> > > more strange and unmotivated?
> > > Applied to this design decision, I would say that the original T/P/O
> are
> > > properties of a single SinkRecord and make sense as getters, and it
> would
> > > be strange to store them in an auxiliary map.
> > >
> > > 2. Following up this change with a compatibility library to make the
> > > interface easier to use is the right choice to make here. This change
> > > should be focused on correctness in allowing developers to fix the
> > > incompatibility and we can be concerned with coming up with a more
> > > ergonomic solution in the compatibility library.
> > > The API should be focused on generality, correctness, and performance
> > > because those cannot be worked-around after the fact. Connector
> > > implementations and/or libraries can be concerned with trading off some
> > > generality and/or performance for ease-of-use.
> > >
> > > 3. I think that the difference in behavior of the new open/close
> methods
> > as
> > > compared to the old methods is significant, and requires good
> > documentation
> > > to help connector developers avoid lazy and incorrect migrations. I am
> > > happy to have that addressed in code review after the KIP is approved.
> > >
> > > I had some questions:
> > >
> > > 4. What is the expected state/behavior for SinkRecords which do not
> have
> > > original T/P/O information after the upgrade? Just browsing, it appears
> > > that tests make extensive use of the existing public SinkRecord
> > > constructors for both Transformations and Connectors.
> > >
> > > 5. What is the expected behavior for Transformation implementations
> which
> > > do not use the newRecord methods and instead use public SinkRecord
> > > constructors? The KIP mentions this as a justification for the
> > > originalKafkaOffset method, but if existing implementations are using
> the
> > > existing constructors, those constructors won't forward the original
> > T/P/O
> > > information to later transforms or the task.
> > >
> > > For the last few points, I want to discuss this rejected alternative:
> > >
> > > > Address the offsets problem entirely within the framework, doing some
> > > kind of mapping from the transformed topic back to the original topic.
> > > > * This would only work in the cases where there’s no overlap between
> > the
> > > transformed topic names, but would break for the rest of the
> > > transformations (e.g. static transformation, topic = “a”).
> > > > * Even if we wanted to limit the support to those cases, it would
> > require
> > > considerable bookkeeping to add a validation to verify that the
> > > transformation chain adheres to that expectation (and fail fast if it
> > > doesn’t).
> > >
> > > 6. This reasoning and the KIP design seems to imply that the connector
> is
> > > better equipped to solve this problem than the framework, but the
> stated
> > > reasons are not convincing for me.
> > > * A static transformation still causes an offset collision in the
> > connector
> > > * The connector is not permitted to see the transformation chain to do
> > any
> > > fail-fast assertions
> > >
> > > Suppose we were to think of the records at the end of the
> transformation
> > > chain as being in "virtual partitions" with "virtual offsets".
> > > For example, with identity-routing SMTs, the virtual coordinates are
> > > exactly the same as the underlying physical coordinates. For 1-1
> renames,
> > > each virtual topic would be the renamed topic corresponding to the
> > > underlying topic. For fan-out from one topic to multiple virtual
> topics,
> > > virtual offsets would use the underlying kafka offsets with gaps for
> > > records going to other virtual partitions. Virtual topics with dropped
> > > records have similar gaps in the offsets.
> > > Currently, these virtual coordinates are passed into the connector via
> > > SinkTask::put, but SinkTask::open/close/preCommit and
> > > SinkTaskContext::assignment/offsets/pause/resume all use physical
> > > coordinates.
> > > This proposal patches put,open, and close to have both physical and
> > virtual
> > > coordinates, but leaves the other methods with physical coordinates.
> > After
> > > this proposal, connectors would be intentionally made aware of the
> > > distinction between physical and virtual coordinates, and manage their
> > own
> > > bookkeeping for the two systems.
> > >
> > > To avoid that connector logic, we could use virtual coordinates in all
> > > connector calls, never revealing that they are different from the
> > physical
> > > coordinates. There's a whole design shopping list that we'd need:
> > > * Renumbering mechanism for disambiguating and making virtual offsets
> > > monotonic in the case of topic/partition collisions
> > > * Data structure and strategy for translating virtual offsets back to
> > > physical offsets
> > > * New limits on SinkTaskContext::offsets() calls to prevent rewinding
> > > before the latest commit
> > > * Backwards compatibility and upgrade design
> > >
> > > 7. This alternative was very appealing to me, because the strength of a
> > > plugin framework is the composability of different components. Among a
> > > collection of N connectors and M transforms, it should ideally only
> take
> > > N + M work to understand how the components combine to build the whole.
> > > However, once you start adding special cases to some plugins to support
> > > interactions with others, the whole system can take N * M work to
> > > understand. From a complexity standpoint, it would be very good for the
> > > framework to solve this in a way which was connector-agnostic.
> > > The current design compromises the logical isolation of the plugins
> > > slightly, but they can collapse offsets very memory-efficiently, and
> > re-use
> > > the existing raw coordinate functions and keep everything else
> backwards
> > > compatible. After deriving all of the above, I think that's a
> reasonable
> > > tradeoff to make.
> > >
> > > Thanks,
> > > Greg
> > >
> > > On Tue, Feb 21, 2023 at 10:17 AM Chris Egerton <chrise@aiven.io.invalid
> >
> > > wrote:
> > >
> > > > Hi Yash,
> > > >
> > > > We'll probably want to make a few tweaks to the Javadocs for the new
> > > > methods (I'm imagining that notes on compatibility with older
> versions
> > > will
> > > > be required), but I believe what's proposed in the KIP is good enough
> > to
> > > > approve with the understanding that it may not exactly match what
> gets
> > > > implemented/merged.
> > > >
> > > > LGTM, thanks again for the KIP!
> > > >
> > > > Cheers,
> > > >
> > > > Chris
> > > >
> > > > On Tue, Feb 21, 2023 at 12:18 PM Yash Mayya <ya...@gmail.com>
> > > wrote:
> > > >
> > > > > Hi Chris,
> > > > >
> > > > > > we might try to introduce a framework-level configuration
> > > > > > property to dictate which of the pre-transform and post-transform
> > > > > > topic partitions are used for the fallback call to the single-arg
> > > > > > variant if a task class has not overridden the multi-arg variant
> > > > >
> > > > > Thanks for the explanation and I agree that this will be a tad bit
> > too
> > > > > convoluted. :)
> > > > >
> > > > > Please do let me know if you'd like any further amendments to the
> > KIP!
> > > > >
> > > > > Thanks,
> > > > > Yash
> > > > >
> > > > > On Tue, Feb 21, 2023 at 8:42 PM Chris Egerton
> > <chrise@aiven.io.invalid
> > > >
> > > > > wrote:
> > > > >
> > > > > > Hi Yash,
> > > > > >
> > > > > > I think the use case for pre-transform TPO coordinates (and topic
> > > > > partition
> > > > > > writers created/destroyed in close/open) tends to boil down to
> > > > > exactly-once
> > > > > > semantics, where it's desirable to preserve the guarantees that
> > Kafka
> > > > > > provides (every record has a unique TPO trio, and records are
> > ordered
> > > > by
> > > > > > offset within a topic partition).
> > > > > >
> > > > > > It's my understanding that this approach is utilized in several
> > > > > connectors
> > > > > > out there today, and it might break these connectors to start
> using
> > > the
> > > > > > post-transform topic partitions automatically in their open/close
> > > > > methods.
> > > > > >
> > > > > > If we want to get really fancy with this and try to obviate or at
> > > least
> > > > > > reduce the need for per-connector code changes, we might try to
> > > > > introduce a
> > > > > > framework-level configuration property to dictate which of the
> > > > > > pre-transform and post-transform topic partitions are used for
> the
> > > > > fallback
> > > > > > call to the single-arg variant if a task class has not overridden
> > the
> > > > > > multi-arg variant. But I think this is going a bit too far and
> > would
> > > > > prefer
> > > > > > to keep things simple(r) for now.
> > > > > >
> > > > > > Cheers,
> > > > > >
> > > > > > Chris
> > > > > >
> > > > > >
> > > > > > On Sun, Feb 19, 2023 at 2:34 AM Yash Mayya <yash.mayya@gmail.com
> >
> > > > wrote:
> > > > > >
> > > > > > > Hi Chris,
> > > > > > >
> > > > > > > > I was actually envisioning something like `void
> > > > > > > > open(Collection<TopicPartition> originalPartitions,
> > > > > > > > Collection<TopicPartition> transformedPartitions)`
> > > > > > >
> > > > > > > Ah okay, this does make a lot more sense. Sorry, I think I
> > > > > misunderstood
> > > > > > > you earlier. I do agree with you that this seems better than
> > > > splitting
> > > > > it
> > > > > > > off into two new sets of open / close methods from a complexity
> > > > > > standpoint.
> > > > > > >
> > > > > > > > Plus, if a connector is intentionally designed to use
> > > > > > > > pre-transformation topic partitions in its open/close
> > > > > > > > methods, wouldn't we just be trading one form of the
> > > > > > > >  problem for another by making this switch?
> > > > > > >
> > > > > > > On thinking about this a bit more, I'm not so convinced that we
> > > need
> > > > to
> > > > > > > expose the pre-transform / original topic partitions in the new
> > > open
> > > > /
> > > > > > > close methods. The purpose of the open / close methods is to
> > allow
> > > > sink
> > > > > > > tasks to allocate and deallocate resources for each topic
> > partition
> > > > > > > assigned to the task and the purpose of topic-mutating SMTs is
> to
> > > > > > > essentially modify the source topic name from the point of view
> > of
> > > > the
> > > > > > sink
> > > > > > > connector. Why would a sink connector ever need to or want to
> > > > allocate
> > > > > > > resources for pre-transform topic partitions? Is the argument
> > here
> > > > that
> > > > > > > since we'll be exposing both the pre-transform and
> post-transform
> > > > topic
> > > > > > > partitions per record, we should also expose the same info via
> > > open /
> > > > > > close
> > > > > > > and allow sink connector implementations to disregard
> > > topic-mutating
> > > > > SMTs
> > > > > > > completely if they wanted to?
> > > > > > >
> > > > > > > Either way, I've gone ahead and updated the KIP to reflect all
> of
> > > > > > > our previous discussion here since it had become quite
> outdated.
> > > I've
> > > > > > also
> > > > > > > updated the KIP title from "Sink Connectors: Support
> > topic-mutating
> > > > > SMTs
> > > > > > > for async connectors (preCommit users)" to "Allow sink
> connectors
> > > to
> > > > be
> > > > > > > used with topic-mutating SMTs" since the improvements to the
> > open /
> > > > > close
> > > > > > > mechanism doesn't pertain only to asynchronous sink connectors.
> > The
> > > > new
> > > > > > KIP
> > > > > > > URL is:
> > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-793%3A+Allow+sink+connectors+to+be+used+with+topic-mutating+SMTs
> > > > > > >
> > > > > > >
> > > > > > > Thanks,
> > > > > > > Yash
> > > > > > >
> > > > > > > On Tue, Feb 14, 2023 at 11:39 PM Chris Egerton
> > > > <chrise@aiven.io.invalid
> > > > > >
> > > > > > > wrote:
> > > > > > >
> > > > > > > > Hi Yash,
> > > > > > > >
> > > > > > > > I was actually envisioning something like `void
> > > > > > > > open(Collection<TopicPartition>
> > > > > > > > originalPartitions, Collection<TopicPartition>
> > > > > transformedPartitions)`,
> > > > > > > > since we already convert and transform each batch of records
> > that
> > > > we
> > > > > > poll
> > > > > > > > from the sink task's consumer en masse, meaning we could
> > discover
> > > > > > several
> > > > > > > > new transformed partitions in between consecutive calls to
> > > > > > SinkTask::put.
> > > > > > > >
> > > > > > > > It's also worth noting that we'll probably want to deprecate
> > the
> > > > > > existing
> > > > > > > > open/close methods, at which point keeping one non-deprecated
> > > > variant
> > > > > > of
> > > > > > > > each seems more appealing and less complex than keeping two.
> > > > > > > >
> > > > > > > > Honestly though, I think we're both on the same page enough
> > that
> > > I
> > > > > > > wouldn't
> > > > > > > > object to either approach. We've probably reached the
> > saturation
> > > > > point
> > > > > > > for
> > > > > > > > ROI here and as long as we provide developers a way to get
> the
> > > > > > > information
> > > > > > > > they need from the runtime and take care to add Javadocs and
> > > update
> > > > > our
> > > > > > > > docs page (possibly including the connector development
> > > > quickstart),
> > > > > it
> > > > > > > > should be fine.
> > > > > > > >
> > > > > > > > At this point, it might be worth updating the KIP based on
> > recent
> > > > > > > > discussion so that others can see the latest proposal, and we
> > can
> > > > > both
> > > > > > > take
> > > > > > > > a look and make sure everything looks good enough before
> > opening
> > > a
> > > > > vote
> > > > > > > > thread.
> > > > > > > >
> > > > > > > > Finally, I think you make a convincing case for a time-based
> > > > eviction
> > > > > > > > policy. I wasn't thinking about the fairly common SMT pattern
> > of
> > > > > > > deriving a
> > > > > > > > topic name from, e.g., a record field or header.
> > > > > > > >
> > > > > > > > Cheers,
> > > > > > > >
> > > > > > > > Chris
> > > > > > > >
> > > > > > > > On Tue, Feb 14, 2023 at 11:42 AM Yash Mayya <
> > > yash.mayya@gmail.com>
> > > > > > > wrote:
> > > > > > > >
> > > > > > > > > Hi Chris,
> > > > > > > > >
> > > > > > > > > > Plus, if a connector is intentionally designed to
> > > > > > > > > > use pre-transformation topic partitions in its
> > > > > > > > > > open/close methods, wouldn't we just be trading
> > > > > > > > > > one form of the problem for another by making this
> > > > > > > > > > switch?
> > > > > > > > >
> > > > > > > > > Thanks, this makes sense, and given that the KIP already
> > > > proposes a
> > > > > > way
> > > > > > > > for
> > > > > > > > > sink connector implementations to distinguish between
> > > > pre-transform
> > > > > > and
> > > > > > > > > post-transform topics per record, I think I'm convinced
> that
> > > > going
> > > > > > with
> > > > > > > > new
> > > > > > > > > `open()` / `close()` methods is the right approach.
> However,
> > I
> > > > > still
> > > > > > > feel
> > > > > > > > > like having overloaded methods will make it a lot less
> > > > unintuitive
> > > > > > > given
> > > > > > > > > that the two sets of methods would be different in terms of
> > > when
> > > > > > > they're
> > > > > > > > > called and what arguments they are passed (also I'm
> presuming
> > > > that
> > > > > > the
> > > > > > > > > overloaded methods you're prescribing will only have a
> single
> > > > > > > > > `TopicPartition` rather than a `Collection<TopicPartition>`
> > as
> > > > > their
> > > > > > > > > parameters). I guess my concern is largely around the fact
> > that
> > > > it
> > > > > > > won't
> > > > > > > > be
> > > > > > > > > possible to distinguish between the overloaded methods' use
> > > cases
> > > > > > just
> > > > > > > > from
> > > > > > > > > the method signatures. I agree that naming is going to be
> > > > difficult
> > > > > > > here,
> > > > > > > > > but I think that having two sets of `SinkTask::openXyz` /
> > > > > > > > > `SinkTask::closeXyz` methods will be less complicated to
> > > > understand
> > > > > > > from
> > > > > > > > a
> > > > > > > > > connector developer perspective (as compared to overloaded
> > > > methods
> > > > > > with
> > > > > > > > > only differing documentation). Of your suggested options, I
> > > think
> > > > > > > > > `openPreTransform` / `openPostTransform` are the most
> > > > > comprehensible
> > > > > > > > ones.
> > > > > > > > >
> > > > > > > > > > BTW, I wouldn't say that we can't make assumptions
> > > > > > > > > > about the relationships between pre- and
> > post-transformation
> > > > > > > > > >  topic partitions.
> > > > > > > > >
> > > > > > > > > I meant that the framework wouldn't be able to
> > > deterministically
> > > > > know
> > > > > > > > when
> > > > > > > > > to close a post-transform topic partition given that SMTs
> > could
> > > > use
> > > > > > > > > per-record data / metadata to manipulate the topic names as
> > and
> > > > how
> > > > > > > > > required (which supports the suggestion to use an eviction
> > > policy
> > > > > > based
> > > > > > > > > mechanism to call SinkTask::close for post-transform topic
> > > > > > partitions).
> > > > > > > > >
> > > > > > > > > > We might utilize a policy that assumes a deterministic
> > > > > > > > > > mapping from the former to the latter, for example.
> > > > > > > > >
> > > > > > > > > Wouldn't this be making the assumption that SMTs only use
> the
> > > > topic
> > > > > > > name
> > > > > > > > > itself and no other data / metadata while computing the new
> > > topic
> > > > > > name?
> > > > > > > > Are
> > > > > > > > > you suggesting that since this assumption could work for a
> > > > majority
> > > > > > of
> > > > > > > > > SMTs, it might be more efficient overall in terms of
> reducing
> > > the
> > > > > > > number
> > > > > > > > of
> > > > > > > > > "false-positive" calls to `SinkTask::closePostTransform`
> (and
> > > > we'll
> > > > > > > also
> > > > > > > > be
> > > > > > > > > able to call `SinkTask::closePostTransform` immediately
> after
> > > > topic
> > > > > > > > > partitions are revoked from the consumer)? I was thinking
> > > > something
> > > > > > > more
> > > > > > > > > generic along the lines of a simple time based eviction
> > policy
> > > > that
> > > > > > > > > wouldn't be making any assumptions regarding the SMT
> > > > > implementations.
> > > > > > > > > Either way, I do like your earlier suggestion of keeping
> this
> > > > logic
> > > > > > > > > internal and not painting ourselves into a corner by
> > promising
> > > > any
> > > > > > > > > particular behavior in the KIP.
> > > > > > > > >
> > > > > > > > > Thanks,
> > > > > > > > > Yash
> > > > > > > > >
> > > > > > > > > On Tue, Feb 14, 2023 at 1:08 AM Chris Egerton
> > > > > > <chrise@aiven.io.invalid
> > > > > > > >
> > > > > > > > > wrote:
> > > > > > > > >
> > > > > > > > > > Hi Yash,
> > > > > > > > > >
> > > > > > > > > > I think the key difference between adding
> methods/overloads
> > > > > related
> > > > > > > to
> > > > > > > > > > SinkTask::open/SinkTask::close and SinkTask::put is that
> > this
> > > > > isn't
> > > > > > > > > > auxiliary information that may or may not be useful to
> > > > connector
> > > > > > > > > > developers. It's actually critical for them to understand
> > the
> > > > > > > > difference
> > > > > > > > > > between the two concepts here, even if they look very
> > > similar.
> > > > > And
> > > > > > > > yes, I
> > > > > > > > > > do believe that switching from pre-transform to
> > > post-transform
> > > > > > topic
> > > > > > > > > > partitions is too big a change in behavior here. Plus,
> if a
> > > > > > connector
> > > > > > > > is
> > > > > > > > > > intentionally designed to use pre-transformation topic
> > > > partitions
> > > > > > in
> > > > > > > > its
> > > > > > > > > > open/close methods, wouldn't we just be trading one form
> of
> > > the
> > > > > > > problem
> > > > > > > > > for
> > > > > > > > > > another by making this switch?
> > > > > > > > > >
> > > > > > > > > > One possible alternative to overloading the existing
> > methods
> > > is
> > > > > to
> > > > > > > > split
> > > > > > > > > > SinkTask::open into openOriginal (or possibly
> openPhysical
> > or
> > > > > > > > > > openPreTransform) and openTransformed (or openLogical or
> > > > > > > > > > openPostTransform), with a similar change for
> > > SinkTask::close.
> > > > > The
> > > > > > > > > default
> > > > > > > > > > implementation for SinkTask::openOriginal can be to call
> > > > > > > > SinkTask::open,
> > > > > > > > > > and the same can go for SinkTask::close. However, I
> prefer
> > > > > > > overloading
> > > > > > > > > the
> > > > > > > > > > existing methods since this alternative increases
> > complexity
> > > > and
> > > > > > none
> > > > > > > > of
> > > > > > > > > > the names are very informative.
> > > > > > > > > >
> > > > > > > > > > BTW, I wouldn't say that we can't make assumptions about
> > the
> > > > > > > > > relationships
> > > > > > > > > > between pre- and post-transformation topic partitions. We
> > > might
> > > > > > > > utilize a
> > > > > > > > > > policy that assumes a deterministic mapping from the
> former
> > > to
> > > > > the
> > > > > > > > > latter,
> > > > > > > > > > for example. The distinction I'd draw is that the
> > assumptions
> > > > we
> > > > > > make
> > > > > > > > can
> > > > > > > > > > and probably should favor some cases in terms of
> > performance
> > > > > (i.e.,
> > > > > > > > > > reducing the number of unnecessary calls to close/open
> > over a
> > > > > given
> > > > > > > > sink
> > > > > > > > > > task's lifetime), but should not lead to guaranteed
> > resource
> > > > > leaks
> > > > > > or
> > > > > > > > > > failure to obey API contract in any cases.
> > > > > > > > > >
> > > > > > > > > > Cheers,
> > > > > > > > > >
> > > > > > > > > > Chris
> > > > > > > > > >
> > > > > > > > > > On Mon, Feb 13, 2023 at 10:54 AM Yash Mayya <
> > > > > yash.mayya@gmail.com>
> > > > > > > > > wrote:
> > > > > > > > > >
> > > > > > > > > > > Hi Chris,
> > > > > > > > > > >
> > > > > > > > > > > > especially if connectors are intentionally designed
> > > around
> > > > > > > > > > > > original topic partitions instead of transformed
> ones.
> > > > > > > > > > >
> > > > > > > > > > > Ha, that's a good point and reminds me of Hyrum's Law
> [1]
> > > :)
> > > > > > > > > > >
> > > > > > > > > > > > I think we have to provide connector developers with
> > some
> > > > > > > > > > > > way to differentiate between the two, but maybe
> > there's a
> > > > way
> > > > > > > > > > > >  to do this that I haven't thought of yet
> > > > > > > > > > >
> > > > > > > > > > > I can't think of a better way to do this either; would
> > > > invoking
> > > > > > the
> > > > > > > > > > > existing `SinkTask::open` and `SinkTask::close` methods
> > > with
> > > > > > > > > > post-transform
> > > > > > > > > > > topic partitions instead of pre-transform topic
> > partitions
> > > > not
> > > > > be
> > > > > > > > > > > acceptable even in a minor / major AK release? I feel
> > like
> > > > the
> > > > > > > > proposed
> > > > > > > > > > > approach of adding overloaded `SinkTask::open` /
> > > > > > `SinkTask::close`
> > > > > > > > > > methods
> > > > > > > > > > > to differentiate between pre-transform and
> post-transform
> > > > topic
> > > > > > > > > > partitions
> > > > > > > > > > > has similar pitfalls to the idea of the overloaded
> > > > > > `SinkTask::put`
> > > > > > > > > method
> > > > > > > > > > > we discarded earlier.
> > > > > > > > > > >
> > > > > > > > > > > > Either way, I'm glad that the general idea of a cache
> > and
> > > > > > > > > > > > eviction policy for SinkTask::close seem reasonable;
> if
> > > > > > > > > > > > we decide to go this route, it might make sense for
> the
> > > KIP
> > > > > > > > > > > > to include an outline of one or more high-level
> > > strategies
> > > > > > > > > > > > we might take, but without promising any particular
> > > > behavior
> > > > > > > > > > > > beyond occasionally calling SinkTask::close for
> > > > > post-transform
> > > > > > > > > > > > topic partitions. I'm hoping that this logic can stay
> > > > > internal,
> > > > > > > > > > > > and by notpainting ourselves into a corner with the
> > KIP,
> > > we
> > > > > > > > > > > > give ourselves leeway to tweak it in the future if
> > > > necessary
> > > > > > > > > > > > without filing another KIP or introducing a pluggable
> > > > > > interface.
> > > > > > > > > > >
> > > > > > > > > > > Thanks, that's a good idea. Given the flexibility of
> > SMTs,
> > > > the
> > > > > > > > > framework
> > > > > > > > > > > can't really make any assumptions around topic
> partitions
> > > > post
> > > > > > > > > > > transformation nor does it have any way to definitively
> > get
> > > > any
> > > > > > > such
> > > > > > > > > > > information from transformations which is why the idea
> > of a
> > > > > cache
> > > > > > > > with
> > > > > > > > > an
> > > > > > > > > > > eviction policy makes perfect sense!
> > > > > > > > > > >
> > > > > > > > > > > [1] - https://www.hyrumslaw.com/
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > Thanks,
> > > > > > > > > > > Yash
> > > > > > > > > > >
> > > > > > > > > > > On Thu, Feb 9, 2023 at 9:38 PM Chris Egerton
> > > > > > > <chrise@aiven.io.invalid
> > > > > > > > >
> > > > > > > > > > > wrote:
> > > > > > > > > > >
> > > > > > > > > > > > Hi Yash,
> > > > > > > > > > > >
> > > > > > > > > > > > > So it looks like with the current state of affairs,
> > > sink
> > > > > > tasks
> > > > > > > > that
> > > > > > > > > > > only
> > > > > > > > > > > > instantiate writers in the SinkTask::open method (and
> > > don't
> > > > > do
> > > > > > > the
> > > > > > > > > lazy
> > > > > > > > > > > > instantiation in SinkTask::put that you mentioned)
> > might
> > > > fail
> > > > > > > when
> > > > > > > > > used
> > > > > > > > > > > > with topic/partition mutating SMTs even if they don't
> > do
> > > > any
> > > > > > > > > > asynchronous
> > > > > > > > > > > > processing?
> > > > > > > > > > > >
> > > > > > > > > > > > Yep, exactly 👍
> > > > > > > > > > > >
> > > > > > > > > > > > > What do you think about retaining just the existing
> > > > methods
> > > > > > > > > > > > but changing when they're called in the Connect
> > runtime?
> > > > For
> > > > > > > > > instance,
> > > > > > > > > > > > instead of calling SinkTask::open after partition
> > > > assignment
> > > > > > > post a
> > > > > > > > > > > > consumer group rebalance, we could cache the
> currently
> > > > "seen"
> > > > > > > topic
> > > > > > > > > > > > partitions (post transformation) and before each call
> > to
> > > > > > > > > SinkTask::put
> > > > > > > > > > > > check whether there's any new "unseen" topic
> > partitions,
> > > > and
> > > > > if
> > > > > > > so
> > > > > > > > > call
> > > > > > > > > > > > SinkTask::open (and also update the cache of course).
> > > > > > > > > > > >
> > > > > > > > > > > > IMO the issue here is that it's a drastic change in
> > > > behavior
> > > > > to
> > > > > > > > start
> > > > > > > > > > > > invoking SinkTask::open and SinkTask::close with
> > > > > post-transform
> > > > > > > > topic
> > > > > > > > > > > > partitions instead of pre-transform, especially if
> > > > connectors
> > > > > > are
> > > > > > > > > > > > intentionally designed around original topic
> partitions
> > > > > instead
> > > > > > > of
> > > > > > > > > > > > transformed ones. I think we have to provide
> connector
> > > > > > developers
> > > > > > > > > with
> > > > > > > > > > > some
> > > > > > > > > > > > way to differentiate between the two, but maybe
> > there's a
> > > > way
> > > > > > to
> > > > > > > do
> > > > > > > > > > this
> > > > > > > > > > > > that I haven't thought of yet. Interested to hear
> your
> > > > > > thoughts.
> > > > > > > > > > > >
> > > > > > > > > > > > Either way, I'm glad that the general idea of a cache
> > and
> > > > > > > eviction
> > > > > > > > > > policy
> > > > > > > > > > > > for SinkTask::close seem reasonable; if we decide to
> go
> > > > this
> > > > > > > route,
> > > > > > > > > it
> > > > > > > > > > > > might make sense for the KIP to include an outline of
> > one
> > > > or
> > > > > > more
> > > > > > > > > > > > high-level strategies we might take, but without
> > > promising
> > > > > any
> > > > > > > > > > particular
> > > > > > > > > > > > behavior beyond occasionally calling SinkTask::close
> > for
> > > > > > > > > post-transform
> > > > > > > > > > > > topic partitions. I'm hoping that this logic can stay
> > > > > internal,
> > > > > > > and
> > > > > > > > > by
> > > > > > > > > > > not
> > > > > > > > > > > > painting ourselves into a corner with the KIP, we
> give
> > > > > > ourselves
> > > > > > > > > leeway
> > > > > > > > > > > to
> > > > > > > > > > > > tweak it in the future if necessary without filing
> > > another
> > > > > KIP
> > > > > > or
> > > > > > > > > > > > introducing a pluggable interface.
> > > > > > > > > > > >
> > > > > > > > > > > > Cheers,
> > > > > > > > > > > >
> > > > > > > > > > > > Chris
> > > > > > > > > > > >
> > > > > > > > > > > > On Thu, Feb 9, 2023 at 7:39 AM Yash Mayya <
> > > > > > yash.mayya@gmail.com>
> > > > > > > > > > wrote:
> > > > > > > > > > > >
> > > > > > > > > > > > > Hi Chris,
> > > > > > > > > > > > >
> > > > > > > > > > > > > Thanks for the feedback.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 1) That's a fair point; while I did scan everything
> > > > > publicly
> > > > > > > > > > available
> > > > > > > > > > > on
> > > > > > > > > > > > > GitHub, you're right in that it won't cover all
> > > possible
> > > > > SMTs
> > > > > > > > that
> > > > > > > > > > are
> > > > > > > > > > > > out
> > > > > > > > > > > > > there. Thanks for the example use-case as well,
> I've
> > > > > updated
> > > > > > > the
> > > > > > > > > KIP
> > > > > > > > > > to
> > > > > > > > > > > > add
> > > > > > > > > > > > > the two new proposed methods.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 2) So it looks like with the current state of
> > affairs,
> > > > sink
> > > > > > > tasks
> > > > > > > > > > that
> > > > > > > > > > > > only
> > > > > > > > > > > > > instantiate writers in the SinkTask::open method
> (and
> > > > don't
> > > > > > do
> > > > > > > > the
> > > > > > > > > > lazy
> > > > > > > > > > > > > instantiation in SinkTask::put that you mentioned)
> > > might
> > > > > fail
> > > > > > > > when
> > > > > > > > > > used
> > > > > > > > > > > > > with topic/partition mutating SMTs even if they
> don't
> > > do
> > > > > any
> > > > > > > > > > > asynchronous
> > > > > > > > > > > > > processing? Since they could encounter records in
> > > > > > SinkTask::put
> > > > > > > > > with
> > > > > > > > > > > > > topics/partitions that they might not have created
> > > > writers
> > > > > > for.
> > > > > > > > > > Thanks
> > > > > > > > > > > > for
> > > > > > > > > > > > > pointing this out, it's definitely another
> > > > incompatibility
> > > > > > that
> > > > > > > > > needs
> > > > > > > > > > > to
> > > > > > > > > > > > be
> > > > > > > > > > > > > called out and fixed. The overloaded method
> approach
> > is
> > > > > > > > > interesting,
> > > > > > > > > > > but
> > > > > > > > > > > > > comes with the caveat of yet more new methods that
> > will
> > > > > need
> > > > > > to
> > > > > > > > be
> > > > > > > > > > > > > implemented by existing connectors if they want to
> > make
> > > > use
> > > > > > of
> > > > > > > > this
> > > > > > > > > > new
> > > > > > > > > > > > > functionality. What do you think about retaining
> just
> > > the
> > > > > > > > existing
> > > > > > > > > > > > methods
> > > > > > > > > > > > > but changing when they're called in the Connect
> > > runtime?
> > > > > For
> > > > > > > > > > instance,
> > > > > > > > > > > > > instead of calling SinkTask::open after partition
> > > > > assignment
> > > > > > > > post a
> > > > > > > > > > > > > consumer group rebalance, we could cache the
> > currently
> > > > > "seen"
> > > > > > > > topic
> > > > > > > > > > > > > partitions (post transformation) and before each
> call
> > > to
> > > > > > > > > > SinkTask::put
> > > > > > > > > > > > > check whether there's any new "unseen" topic
> > > partitions,
> > > > > and
> > > > > > if
> > > > > > > > so
> > > > > > > > > > call
> > > > > > > > > > > > > SinkTask::open (and also update the cache of
> > course). I
> > > > > don't
> > > > > > > > think
> > > > > > > > > > > this
> > > > > > > > > > > > > would break the existing contract with sink tasks
> > where
> > > > > > > > > > SinkTask::open
> > > > > > > > > > > is
> > > > > > > > > > > > > expected to be called for a topic partition before
> > any
> > > > > > records
> > > > > > > > from
> > > > > > > > > > the
> > > > > > > > > > > > > topic partition are sent via SinkTask::put? The
> > > > > > SinkTask::close
> > > > > > > > > case
> > > > > > > > > > > is a
> > > > > > > > > > > > > lot trickier however, and would require some sort
> of
> > > > cache
> > > > > > > > eviction
> > > > > > > > > > > > policy
> > > > > > > > > > > > > that would be deemed appropriate as you pointed out
> > > too.
> > > > > > > > > > > > >
> > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > Yash
> > > > > > > > > > > > >
> > > > > > > > > > > > > On Mon, Feb 6, 2023 at 11:27 PM Chris Egerton
> > > > > > > > > > <chrise@aiven.io.invalid
> > > > > > > > > > > >
> > > > > > > > > > > > > wrote:
> > > > > > > > > > > > >
> > > > > > > > > > > > > > Hi Yash,
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > I've had some time to think on this KIP and I
> think
> > > I'm
> > > > > in
> > > > > > > > > > agreement
> > > > > > > > > > > > > about
> > > > > > > > > > > > > > not blocking it on an official compatibility
> > library
> > > or
> > > > > > > adding
> > > > > > > > > the
> > > > > > > > > > > > "ack"
> > > > > > > > > > > > > > API for sink records.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > I only have two more thoughts:
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 1. Because it is possible to manipulate sink
> record
> > > > > > > partitions
> > > > > > > > > and
> > > > > > > > > > > > > offsets
> > > > > > > > > > > > > > with the current API we provide for
> > transformations,
> > > I
> > > > > > still
> > > > > > > > > > believe
> > > > > > > > > > > > > > methods should be added to the SinkRecord class
> to
> > > > expose
> > > > > > the
> > > > > > > > > > > original
> > > > > > > > > > > > > > partition and offset, not just the original
> topic.
> > > The
> > > > > > > > additional
> > > > > > > > > > > > > cognitive
> > > > > > > > > > > > > > burden from these two methods is going to be
> > minimal
> > > > > > anyways;
> > > > > > > > > once
> > > > > > > > > > > > users
> > > > > > > > > > > > > > understand the difference between the transformed
> > > topic
> > > > > > name
> > > > > > > > and
> > > > > > > > > > the
> > > > > > > > > > > > > > original one, it's going to be trivial for them
> to
> > > > > > understand
> > > > > > > > how
> > > > > > > > > > > that
> > > > > > > > > > > > > same
> > > > > > > > > > > > > > difference applies for partitions and offsets.
> It's
> > > not
> > > > > > > enough
> > > > > > > > to
> > > > > > > > > > > scan
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > set of SMTs provided out of the box with Connect,
> > > ones
> > > > > > > > developed
> > > > > > > > > by
> > > > > > > > > > > > > > Confluent, or even everything available on
> GitHub,
> > > > since
> > > > > > > there
> > > > > > > > > may
> > > > > > > > > > be
> > > > > > > > > > > > > > closed-source projects out there that rely on
> this
> > > > > ability.
> > > > > > > One
> > > > > > > > > > > > potential
> > > > > > > > > > > > > > use case could be re-routing partitions between
> > Kafka
> > > > and
> > > > > > > some
> > > > > > > > > > other
> > > > > > > > > > > > > > sharded system.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > 2. We still have to address the SinkTask::open
> [1]
> > > and
> > > > > > > > > > > SinkTask::close
> > > > > > > > > > > > > [2]
> > > > > > > > > > > > > > methods. If a connector writes to the external
> > system
> > > > > using
> > > > > > > the
> > > > > > > > > > > > > transformed
> > > > > > > > > > > > > > topic partitions it reads from Kafka, then it's
> > > > possible
> > > > > > for
> > > > > > > > the
> > > > > > > > > > > > > connector
> > > > > > > > > > > > > > to lazily instantiate writers for topic
> partitions
> > as
> > > > it
> > > > > > > > > encounters
> > > > > > > > > > > > them
> > > > > > > > > > > > > > from records provided in SinkTask::put. However,
> > > > > connectors
> > > > > > > > also
> > > > > > > > > > > need a
> > > > > > > > > > > > > way
> > > > > > > > > > > > > > to de-allocate those writers (and the resources
> > used
> > > by
> > > > > > them)
> > > > > > > > > over
> > > > > > > > > > > > time,
> > > > > > > > > > > > > > which they can't do as easily. One possible
> > approach
> > > > here
> > > > > > is
> > > > > > > to
> > > > > > > > > > > > overload
> > > > > > > > > > > > > > SinkTask::open and SinkTask::close with variants
> > that
> > > > > > > > distinguish
> > > > > > > > > > > > between
> > > > > > > > > > > > > > transformed and original topic partitions, and
> > > default
> > > > to
> > > > > > > > > invoking
> > > > > > > > > > > the
> > > > > > > > > > > > > > existing methods with just the original topic
> > > > partitions.
> > > > > > We
> > > > > > > > > would
> > > > > > > > > > > then
> > > > > > > > > > > > > > have several options for how the Connect runtime
> > can
> > > > > invoke
> > > > > > > > these
> > > > > > > > > > > > > methods,
> > > > > > > > > > > > > > but in general, an approach that guarantees that
> > > tasks
> > > > > are
> > > > > > > > > notified
> > > > > > > > > > > of
> > > > > > > > > > > > > > transformed topic partitions in SinkTask::open
> > before
> > > > any
> > > > > > > > records
> > > > > > > > > > for
> > > > > > > > > > > > > that
> > > > > > > > > > > > > > partition are given to it in SinkTask::put, and
> > > makes a
> > > > > > > > > best-effort
> > > > > > > > > > > > > attempt
> > > > > > > > > > > > > > to close transformed topic partitions that appear
> > to
> > > no
> > > > > > > longer
> > > > > > > > be
> > > > > > > > > > in
> > > > > > > > > > > > use
> > > > > > > > > > > > > > based on some eviction policy, would probably be
> > > > > > sufficient.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > [1] -
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://kafka.apache.org/33/javadoc/org/apache/kafka/connect/sink/SinkTask.html#open(java.util.Collection)
> > > > > > > > > > > > > > [2] -
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://kafka.apache.org/33/javadoc/org/apache/kafka/connect/sink/SinkTask.html#close(java.util.Collection)
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Cheers,
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Chris
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > On Sat, Nov 5, 2022 at 5:46 AM Yash Mayya <
> > > > > > > > yash.mayya@gmail.com>
> > > > > > > > > > > > wrote:
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Hi Chris,
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Thanks a lot for your inputs!
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > would provide a simple, clean interface for
> > > > > developers
> > > > > > to
> > > > > > > > > > > determine
> > > > > > > > > > > > > > > > which features are supported by the version
> of
> > > the
> > > > > > > Connect
> > > > > > > > > > > runtime
> > > > > > > > > > > > > > > > that their plugin has been deployed onto
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > I do like the idea of having such a public
> > > > > compatibility
> > > > > > > > > library
> > > > > > > > > > -
> > > > > > > > > > > I
> > > > > > > > > > > > > > think
> > > > > > > > > > > > > > > it would remove a lot of restrictions from
> > > framework
> > > > > > > > > development
> > > > > > > > > > if
> > > > > > > > > > > > it
> > > > > > > > > > > > > > were
> > > > > > > > > > > > > > > to be widely adopted.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > we might consider adding an API to "ack" sink
> > > > records
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > I agree that this does seem like a more
> intuitive
> > > and
> > > > > > clean
> > > > > > > > > API,
> > > > > > > > > > > but
> > > > > > > > > > > > > I'm
> > > > > > > > > > > > > > > concerned about the backward compatibility
> > headache
> > > > > we'd
> > > > > > be
> > > > > > > > > > > imposing
> > > > > > > > > > > > on
> > > > > > > > > > > > > > all
> > > > > > > > > > > > > > > existing sink connectors. Connector developers
> > will
> > > > > have
> > > > > > to
> > > > > > > > > > > maintain
> > > > > > > > > > > > > two
> > > > > > > > > > > > > > > separate ways of doing offset management if
> they
> > > want
> > > > > to
> > > > > > > use
> > > > > > > > > the
> > > > > > > > > > > new
> > > > > > > > > > > > > API
> > > > > > > > > > > > > > > but continue supporting older versions of Kafka
> > > > > Connect.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > For now, I've reverted the KIP to the previous
> > > > > iteration
> > > > > > > > which
> > > > > > > > > > > > proposed
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > addition of a new `SinkRecord` method to obtain
> > the
> > > > > > > original
> > > > > > > > > > Kafka
> > > > > > > > > > > > > topic
> > > > > > > > > > > > > > > pre-transformation. One thing to note is that
> > I've
> > > > > > removed
> > > > > > > > the
> > > > > > > > > > > method
> > > > > > > > > > > > > for
> > > > > > > > > > > > > > > obtaining the original Kafka partition after a
> > > > cursory
> > > > > > > search
> > > > > > > > > > > showed
> > > > > > > > > > > > > that
> > > > > > > > > > > > > > > use cases for partition modifying SMTs are
> > > primarily
> > > > on
> > > > > > the
> > > > > > > > > > source
> > > > > > > > > > > > > > > connector side.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > Yash
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > On Tue, Nov 1, 2022 at 9:22 PM Chris Egerton
> > > > > > > > > > > <chrise@aiven.io.invalid
> > > > > > > > > > > > >
> > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Hi all,
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > I have more comments I'd like to make on this
> > KIP
> > > > > when
> > > > > > I
> > > > > > > > have
> > > > > > > > > > > time
> > > > > > > > > > > > > > (sorry
> > > > > > > > > > > > > > > > for the delay, Yash, and thanks for your
> > > > patience!),
> > > > > > but
> > > > > > > I
> > > > > > > > > did
> > > > > > > > > > > want
> > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > chime in and say that I'm also not sure about
> > > > > > overloading
> > > > > > > > > > > > > > SinkTask::put.
> > > > > > > > > > > > > > > I
> > > > > > > > > > > > > > > > share the concerns about creating an
> intuitive,
> > > > > simple
> > > > > > > API
> > > > > > > > > that
> > > > > > > > > > > > Yash
> > > > > > > > > > > > > > has
> > > > > > > > > > > > > > > > raised. In addition, this approach doesn't
> seem
> > > > very
> > > > > > > > > > > > > sustainable--what
> > > > > > > > > > > > > > do
> > > > > > > > > > > > > > > > we do if we encounter another case in the
> > future
> > > > that
> > > > > > > would
> > > > > > > > > > > > warrant a
> > > > > > > > > > > > > > > > similar solution? We probably don't want to
> > > create
> > > > > > three,
> > > > > > > > > four,
> > > > > > > > > > > > etc.
> > > > > > > > > > > > > > > > overloaded variants of the method, each of
> > which
> > > > > would
> > > > > > > have
> > > > > > > > > to
> > > > > > > > > > be
> > > > > > > > > > > > > > > > implemented by connector developers who want
> to
> > > > both
> > > > > > > > leverage
> > > > > > > > > > the
> > > > > > > > > > > > > > latest
> > > > > > > > > > > > > > > > and greatest connector APIs and maintain
> > > > > compatibility
> > > > > > > with
> > > > > > > > > > > connect
> > > > > > > > > > > > > > > > Clusters running older versions.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > I haven't been able to flesh this out into a
> > > design
> > > > > > worth
> > > > > > > > > > > > publishing
> > > > > > > > > > > > > in
> > > > > > > > > > > > > > > its
> > > > > > > > > > > > > > > > own KIP yet, but one alternative I've pitched
> > to
> > > a
> > > > > few
> > > > > > > > people
> > > > > > > > > > > with
> > > > > > > > > > > > > > > > generally positive interest has been to
> develop
> > > an
> > > > > > > official
> > > > > > > > > > > > > > compatibility
> > > > > > > > > > > > > > > > library for Connect developers. This library
> > > would
> > > > be
> > > > > > > > > released
> > > > > > > > > > as
> > > > > > > > > > > > its
> > > > > > > > > > > > > > own
> > > > > > > > > > > > > > > > Maven artifact (separate from connect-api,
> > > > > > > connect-runtime,
> > > > > > > > > > etc.)
> > > > > > > > > > > > and
> > > > > > > > > > > > > > > would
> > > > > > > > > > > > > > > > provide a simple, clean interface for
> > developers
> > > to
> > > > > > > > determine
> > > > > > > > > > > which
> > > > > > > > > > > > > > > > features are supported by the version of the
> > > > Connect
> > > > > > > > runtime
> > > > > > > > > > that
> > > > > > > > > > > > > their
> > > > > > > > > > > > > > > > plugin has been deployed onto. Under the
> hood,
> > > this
> > > > > > > library
> > > > > > > > > > might
> > > > > > > > > > > > use
> > > > > > > > > > > > > > > > reflection to determine whether classes,
> > methods,
> > > > > etc.
> > > > > > > are
> > > > > > > > > > > > available,
> > > > > > > > > > > > > > but
> > > > > > > > > > > > > > > > the developer wouldn't have to do anything
> more
> > > > than
> > > > > > > check
> > > > > > > > > (for
> > > > > > > > > > > > > > example)
> > > > > > > > > > > > > > > >
> > > > `Features.SINK_TASK_ERRANT_RECORD_REPORTER.enabled()`
> > > > > > to
> > > > > > > > know
> > > > > > > > > > at
> > > > > > > > > > > > any
> > > > > > > > > > > > > > > point
> > > > > > > > > > > > > > > > in the lifetime of their connector/task
> whether
> > > > that
> > > > > > > > feature
> > > > > > > > > is
> > > > > > > > > > > > > > provided
> > > > > > > > > > > > > > > by
> > > > > > > > > > > > > > > > the runtime.
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > One other high-level comment: this doesn't
> > > address
> > > > > > every
> > > > > > > > > case,
> > > > > > > > > > > but
> > > > > > > > > > > > we
> > > > > > > > > > > > > > > might
> > > > > > > > > > > > > > > > consider adding an API to "ack" sink records.
> > > This
> > > > > > could
> > > > > > > > use
> > > > > > > > > > the
> > > > > > > > > > > > > > > > SubmittedRecords class [1] (with some slight
> > > > tweaks)
> > > > > > > under
> > > > > > > > > the
> > > > > > > > > > > hood
> > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > track the latest-acked offset for each topic
> > > > > partition.
> > > > > > > > This
> > > > > > > > > > way,
> > > > > > > > > > > > > > > connector
> > > > > > > > > > > > > > > > developers won't be responsible for tracking
> > > > offsets
> > > > > at
> > > > > > > all
> > > > > > > > > in
> > > > > > > > > > > > their
> > > > > > > > > > > > > > sink
> > > > > > > > > > > > > > > > tasks (eliminating issues with the accuracy
> of
> > > > > > > > > > > post-transformation
> > > > > > > > > > > > > > T/P/O
> > > > > > > > > > > > > > > > sink record information), and they'll only
> have
> > > to
> > > > > > notify
> > > > > > > > the
> > > > > > > > > > > > Connect
> > > > > > > > > > > > > > > > framework when a record has been successfully
> > > > > > dispatched
> > > > > > > to
> > > > > > > > > the
> > > > > > > > > > > > > > external
> > > > > > > > > > > > > > > > system. This provides a cleaner, friendlier
> > API,
> > > > and
> > > > > > also
> > > > > > > > > > enables
> > > > > > > > > > > > > more
> > > > > > > > > > > > > > > > fine-grained metrics like the ones proposed
> in
> > > > > KIP-767
> > > > > > > [2].
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > [1] -
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://github.com/apache/kafka/blob/9ab140d5419d735baae45aff56ffce7f5622744f/connect/runtime/src/main/java/org/apache/kafka/connect/runtime/SubmittedRecords.java
> > > > > > > > > > > > > > > > [2] -
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-767%3A+Connect+Latency+Metrics
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Cheers,
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Chris
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > On Tue, Nov 1, 2022 at 11:21 AM Yash Mayya <
> > > > > > > > > > yash.mayya@gmail.com
> > > > > > > > > > > >
> > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Hi Randall,
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > It's been a while for this one but the
> more I
> > > > think
> > > > > > > about
> > > > > > > > > it,
> > > > > > > > > > > the
> > > > > > > > > > > > > > more
> > > > > > > > > > > > > > > I
> > > > > > > > > > > > > > > > > feel like the current approach with a new
> > > > > overloaded
> > > > > > > > > > > > > `SinkTask::put`
> > > > > > > > > > > > > > > > method
> > > > > > > > > > > > > > > > > might not be optimal. We're trying to fix a
> > > > pretty
> > > > > > > corner
> > > > > > > > > > case
> > > > > > > > > > > > bug
> > > > > > > > > > > > > > here
> > > > > > > > > > > > > > > > > (usage of topic mutating SMTs with sink
> > > > connectors
> > > > > > that
> > > > > > > > do
> > > > > > > > > > > their
> > > > > > > > > > > > > own
> > > > > > > > > > > > > > > > offset
> > > > > > > > > > > > > > > > > tracking) and I'm not sure that warrants a
> > > change
> > > > > to
> > > > > > > > such a
> > > > > > > > > > > > central
> > > > > > > > > > > > > > > > > interface method. The new `SinkTask::put`
> > > method
> > > > > just
> > > > > > > > seems
> > > > > > > > > > > > > somewhat
> > > > > > > > > > > > > > > odd
> > > > > > > > > > > > > > > > > and it may not be very understandable for a
> > new
> > > > > > reader
> > > > > > > -
> > > > > > > > I
> > > > > > > > > > > don't
> > > > > > > > > > > > > > think
> > > > > > > > > > > > > > > > this
> > > > > > > > > > > > > > > > > should be the case for a public interface
> > > method.
> > > > > > > > > > Furthermore,
> > > > > > > > > > > > even
> > > > > > > > > > > > > > > with
> > > > > > > > > > > > > > > > > elaborate documentation in place, I'm not
> > sure
> > > if
> > > > > > it'll
> > > > > > > > be
> > > > > > > > > > very
> > > > > > > > > > > > > > obvious
> > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > most people what the purpose of having
> these
> > > two
> > > > > > `put`
> > > > > > > > > > methods
> > > > > > > > > > > is
> > > > > > > > > > > > > and
> > > > > > > > > > > > > > > how
> > > > > > > > > > > > > > > > > they should be used by sink task
> > > implementations.
> > > > > > What
> > > > > > > do
> > > > > > > > > you
> > > > > > > > > > > > > think?
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > > Yash
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > On Mon, Oct 10, 2022 at 9:33 PM Yash Mayya
> <
> > > > > > > > > > > yash.mayya@gmail.com
> > > > > > > > > > > > >
> > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > Hi Randall,
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > Thanks a lot for your valuable feedback
> so
> > > far!
> > > > > > I've
> > > > > > > > > > updated
> > > > > > > > > > > > the
> > > > > > > > > > > > > > KIP
> > > > > > > > > > > > > > > > > based
> > > > > > > > > > > > > > > > > > on our discussion above. Could you please
> > > take
> > > > > > > another
> > > > > > > > > > look?
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > > > Yash
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > > On Tue, Oct 4, 2022 at 12:40 AM Randall
> > > Hauch <
> > > > > > > > > > > > rhauch@gmail.com>
> > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >> On Mon, Oct 3, 2022 at 11:45 AM Yash
> > Mayya <
> > > > > > > > > > > > > yash.mayya@gmail.com>
> > > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >> > Hi Randall,
> > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > >> > Thanks for elaborating. I think these
> > are
> > > > all
> > > > > > very
> > > > > > > > > good
> > > > > > > > > > > > points
> > > > > > > > > > > > > > > and I
> > > > > > > > > > > > > > > > > see
> > > > > > > > > > > > > > > > > >> > why the overloaded `SinkTask::put`
> > method
> > > > is a
> > > > > > > > cleaner
> > > > > > > > > > > > > solution
> > > > > > > > > > > > > > > > > overall.
> > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > >> > > public void
> put(Collection<SinkRecord>
> > > > > > records,
> > > > > > > > > > > > > > Map<SinkRecord,
> > > > > > > > > > > > > > > > > >> > TopicPartition>
> updatedTopicPartitions)
> > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > >> > I think this should be
> > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > >> > `public void
> put(Collection<SinkRecord>
> > > > > records,
> > > > > > > > > > > > > Map<SinkRecord,
> > > > > > > > > > > > > > > > > >> > TopicPartition>
> > originalTopicPartitions)`
> > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > >> > instead because the sink records
> > > themselves
> > > > > have
> > > > > > > the
> > > > > > > > > > > updated
> > > > > > > > > > > > > > topic
> > > > > > > > > > > > > > > > > >> > partitions (i.e. after all
> > transformations
> > > > > have
> > > > > > > been
> > > > > > > > > > > > applied)
> > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > >> KIP
> > > > > > > > > > > > > > > > > >> > is proposing a way for the tasks to be
> > > able
> > > > to
> > > > > > > > access
> > > > > > > > > > the
> > > > > > > > > > > > > > original
> > > > > > > > > > > > > > > > > topic
> > > > > > > > > > > > > > > > > >> > partition (i.e. before transformations
> > > have
> > > > > been
> > > > > > > > > > applied).
> > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >> Sounds good.
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > >> > > Of course, if the developer does not
> > > need
> > > > > > > separate
> > > > > > > > > > > > methods,
> > > > > > > > > > > > > > they
> > > > > > > > > > > > > > > > can
> > > > > > > > > > > > > > > > > >> > easily have the older `put` method
> > simply
> > > > > > delegate
> > > > > > > > to
> > > > > > > > > > the
> > > > > > > > > > > > > newer
> > > > > > > > > > > > > > > > > method.
> > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > >> > If the developer does not need
> separate
> > > > > methods
> > > > > > > > (i.e.
> > > > > > > > > > they
> > > > > > > > > > > > > don't
> > > > > > > > > > > > > > > > need
> > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > >> > use this new addition), they can
> simply
> > > > > continue
> > > > > > > > > > > > implementing
> > > > > > > > > > > > > > just
> > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > >> > older `put` method right?
> > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >> Correct. We should update the JavaDoc of
> > > both
> > > > > > > methods
> > > > > > > > to
> > > > > > > > > > > make
> > > > > > > > > > > > > this
> > > > > > > > > > > > > > > > > clear,
> > > > > > > > > > > > > > > > > >> and in general how the two methods
> should
> > > are
> > > > > used
> > > > > > > and
> > > > > > > > > > > should
> > > > > > > > > > > > be
> > > > > > > > > > > > > > > > > >> implemented. That can be part of the PR,
> > and
> > > > the
> > > > > > KIP
> > > > > > > > > > doesn't
> > > > > > > > > > > > > need
> > > > > > > > > > > > > > > this
> > > > > > > > > > > > > > > > > >> wording.
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > >> > > Finally, this gives us a roadmap for
> > > > > > > *eventually*
> > > > > > > > > > > > > deprecating
> > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > >> older
> > > > > > > > > > > > > > > > > >> > method, once the Connect runtime
> > versions
> > > > > > without
> > > > > > > > this
> > > > > > > > > > > > change
> > > > > > > > > > > > > > are
> > > > > > > > > > > > > > > > old
> > > > > > > > > > > > > > > > > >> > enough.
> > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > >> > I'm not sure we'd ever want to
> deprecate
> > > the
> > > > > > older
> > > > > > > > > > method.
> > > > > > > > > > > > > Most
> > > > > > > > > > > > > > > > common
> > > > > > > > > > > > > > > > > >> sink
> > > > > > > > > > > > > > > > > >> > connector implementations do not do
> > their
> > > > own
> > > > > > > offset
> > > > > > > > > > > > tracking
> > > > > > > > > > > > > > with
> > > > > > > > > > > > > > > > > >> > asynchronous processing and will
> > probably
> > > > > never
> > > > > > > > have a
> > > > > > > > > > > need
> > > > > > > > > > > > > for
> > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > >> > additional parameter `Map<SinkRecord,
> > > > > > > > TopicPartition>
> > > > > > > > > > > > > > > > > >> > originalTopicPartitions` in the
> proposed
> > > new
> > > > > > `put`
> > > > > > > > > > method.
> > > > > > > > > > > > > These
> > > > > > > > > > > > > > > > > >> connectors
> > > > > > > > > > > > > > > > > >> > can continue implementing only the
> > > existing
> > > > > > > > > > > `SinkTask::put`
> > > > > > > > > > > > > > method
> > > > > > > > > > > > > > > > > which
> > > > > > > > > > > > > > > > > >> > will be called by the default
> > > implementation
> > > > > of
> > > > > > > the
> > > > > > > > > > newer
> > > > > > > > > > > > > > > overloaded
> > > > > > > > > > > > > > > > > >> `put`
> > > > > > > > > > > > > > > > > >> > method.
> > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >> +1
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > >> > > the pre-commit methods use the same
> > > > > > > > > > `Map<TopicPartition,
> > > > > > > > > > > > > > > > > >> > OffsetAndMetadata> currentOffsets`
> data
> > > > > > structure
> > > > > > > > I'm
> > > > > > > > > > > > > suggesting
> > > > > > > > > > > > > > > be
> > > > > > > > > > > > > > > > > >> used.
> > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > >> > The data structure you're suggesting
> be
> > > used
> > > > > is
> > > > > > a
> > > > > > > > > > > > > > `Map<SinkRecord,
> > > > > > > > > > > > > > > > > >> > TopicPartition>` which will map
> > > `SinkRecord`
> > > > > > > objects
> > > > > > > > > to
> > > > > > > > > > > the
> > > > > > > > > > > > > > > original
> > > > > > > > > > > > > > > > > >> topic
> > > > > > > > > > > > > > > > > >> > partition of the corresponding
> > > > > `ConsumerRecord`
> > > > > > > > right?
> > > > > > > > > > To
> > > > > > > > > > > > > > clarify,
> > > > > > > > > > > > > > > > > this
> > > > > > > > > > > > > > > > > >> is
> > > > > > > > > > > > > > > > > >> > a new data structure that will need to
> > be
> > > > > > managed
> > > > > > > in
> > > > > > > > > the
> > > > > > > > > > > > > > > > > >> `WorkerSinkTask`.
> > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >> Ah, you're right. Thanks for the
> > correction.
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >> Best regards,
> > > > > > > > > > > > > > > > > >> Randall
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >> > Thanks,
> > > > > > > > > > > > > > > > > >> > Yash
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >> > On Mon, Oct 3, 2022 at 1:20 AM Randall
> > > > Hauch <
> > > > > > > > > > > > > rhauch@gmail.com>
> > > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > >> > > Hi, Yash.
> > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > >> > > I'm not sure I quite understand why
> it
> > > > would
> > > > > > be
> > > > > > > > > > "easier"
> > > > > > > > > > > > for
> > > > > > > > > > > > > > > > > connector
> > > > > > > > > > > > > > > > > >> > > > developers to account for
> > implementing
> > > > two
> > > > > > > > > different
> > > > > > > > > > > > > > > overloaded
> > > > > > > > > > > > > > > > > >> `put`
> > > > > > > > > > > > > > > > > >> > > > methods (assuming that they want
> to
> > > use
> > > > > this
> > > > > > > new
> > > > > > > > > > > > feature)
> > > > > > > > > > > > > > > versus
> > > > > > > > > > > > > > > > > >> using
> > > > > > > > > > > > > > > > > >> > a
> > > > > > > > > > > > > > > > > >> > > > try-catch block around
> `SinkRecord`
> > > > access
> > > > > > > > > methods?
> > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > >> > > Using a try-catch to try around an
> API
> > > > > method
> > > > > > > that
> > > > > > > > > > > *might*
> > > > > > > > > > > > > be
> > > > > > > > > > > > > > > > there
> > > > > > > > > > > > > > > > > >> is a
> > > > > > > > > > > > > > > > > >> > > very unusual thing for most
> > developers.
> > > > > > > > > Unfortunately,
> > > > > > > > > > > > we've
> > > > > > > > > > > > > > had
> > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > >> > resort
> > > > > > > > > > > > > > > > > >> > > to this atypical approach with
> Connect
> > > in
> > > > > > places
> > > > > > > > > when
> > > > > > > > > > > > there
> > > > > > > > > > > > > > was
> > > > > > > > > > > > > > > no
> > > > > > > > > > > > > > > > > >> good
> > > > > > > > > > > > > > > > > >> > > alternative. We seem to relying upon
> > > > pattern
> > > > > > > > because
> > > > > > > > > > > it's
> > > > > > > > > > > > > > easier
> > > > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > > >> us,
> > > > > > > > > > > > > > > > > >> > > not because it offers a better
> > > experience
> > > > > for
> > > > > > > > > > Connector
> > > > > > > > > > > > > > > > developers.
> > > > > > > > > > > > > > > > > >> IMO,
> > > > > > > > > > > > > > > > > >> > if
> > > > > > > > > > > > > > > > > >> > > there's a practical alternative that
> > > uses
> > > > > > normal
> > > > > > > > > > > > development
> > > > > > > > > > > > > > > > > practices
> > > > > > > > > > > > > > > > > >> > and
> > > > > > > > > > > > > > > > > >> > > techniques, then we should use that
> > > > > > alternative.
> > > > > > > > > IIUC,
> > > > > > > > > > > > there
> > > > > > > > > > > > > > is
> > > > > > > > > > > > > > > at
> > > > > > > > > > > > > > > > > >> least
> > > > > > > > > > > > > > > > > >> > > one practical alternative for this
> KIP
> > > > that
> > > > > > > would
> > > > > > > > > not
> > > > > > > > > > > > > require
> > > > > > > > > > > > > > > > > >> developers
> > > > > > > > > > > > > > > > > >> > to
> > > > > > > > > > > > > > > > > >> > > use the unusual try-catch to handle
> > the
> > > > case
> > > > > > > where
> > > > > > > > > > > methods
> > > > > > > > > > > > > are
> > > > > > > > > > > > > > > not
> > > > > > > > > > > > > > > > > >> found.
> > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > >> > > I also think having two `put`
> methods
> > is
> > > > > > easier
> > > > > > > > when
> > > > > > > > > > the
> > > > > > > > > > > > > > > Connector
> > > > > > > > > > > > > > > > > >> has to
> > > > > > > > > > > > > > > > > >> > > do different things for different
> > > Connect
> > > > > > > > runtimes,
> > > > > > > > > > too.
> > > > > > > > > > > > One
> > > > > > > > > > > > > > of
> > > > > > > > > > > > > > > > > those
> > > > > > > > > > > > > > > > > >> > > methods is called by newer Connect
> > > > runtimes
> > > > > > with
> > > > > > > > the
> > > > > > > > > > new
> > > > > > > > > > > > > > > behavior,
> > > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > >> > the
> > > > > > > > > > > > > > > > > >> > > other method is called by an older
> > > Connect
> > > > > > > > runtime.
> > > > > > > > > Of
> > > > > > > > > > > > > course,
> > > > > > > > > > > > > > > if
> > > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > >> > > developer does not need separate
> > > methods,
> > > > > they
> > > > > > > can
> > > > > > > > > > > easily
> > > > > > > > > > > > > have
> > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > >> older
> > > > > > > > > > > > > > > > > >> > > `put` method simply delegate to the
> > > newer
> > > > > > > method.
> > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > >> > > Finally, this gives us a roadmap for
> > > > > > > *eventually*
> > > > > > > > > > > > > deprecating
> > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > >> older
> > > > > > > > > > > > > > > > > >> > > method, once the Connect runtime
> > > versions
> > > > > > > without
> > > > > > > > > this
> > > > > > > > > > > > > change
> > > > > > > > > > > > > > > are
> > > > > > > > > > > > > > > > > old
> > > > > > > > > > > > > > > > > >> > > enough.
> > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > >> > > I think the advantage of going with
> > the
> > > > > > > > > > > > > > > > > >> > > > proposed approach in the KIP is
> that
> > > it
> > > > > > > wouldn't
> > > > > > > > > > > require
> > > > > > > > > > > > > > extra
> > > > > > > > > > > > > > > > > >> > > book-keeping
> > > > > > > > > > > > > > > > > >> > > > (the Map<SinkRecord,
> > > > > > > > > > > > > > > > > >> > > > TopicPartition> in
> `WorkerSinkTask`
> > in
> > > > > your
> > > > > > > > > proposed
> > > > > > > > > > > > > > approach)
> > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > >> > > The connector does have to do some
> of
> > > this
> > > > > > > > > bookkeeping
> > > > > > > > > > > in
> > > > > > > > > > > > > how
> > > > > > > > > > > > > > > they
> > > > > > > > > > > > > > > > > >> track
> > > > > > > > > > > > > > > > > >> > > the topic partition offsets used in
> > the
> > > > > > > > `preCommit`,
> > > > > > > > > > and
> > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > >> pre-commit
> > > > > > > > > > > > > > > > > >> > > methods use the same
> > > `Map<TopicPartition,
> > > > > > > > > > > > OffsetAndMetadata>
> > > > > > > > > > > > > > > > > >> > > currentOffsets`
> > > > > > > > > > > > > > > > > >> > > data structure I'm suggesting be
> used.
> > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > >> > > I hope that helps.
> > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > >> > > Best regards,
> > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > >> > > Randall
> > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > >> > > On Mon, Sep 26, 2022 at 9:38 AM Yash
> > > > Mayya <
> > > > > > > > > > > > > > > yash.mayya@gmail.com>
> > > > > > > > > > > > > > > > > >> wrote:
> > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > >> > > > Hi Randall,
> > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > >> > > > Thanks for reviewing the KIP!
> > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > >> > > > > That latter logic can get quite
> > > ugly.
> > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > >> > > > I'm not sure I quite understand
> why
> > it
> > > > > would
> > > > > > > be
> > > > > > > > > > > "easier"
> > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > > >> connector
> > > > > > > > > > > > > > > > > >> > > > developers to account for
> > implementing
> > > > two
> > > > > > > > > different
> > > > > > > > > > > > > > > overloaded
> > > > > > > > > > > > > > > > > >> `put`
> > > > > > > > > > > > > > > > > >> > > > methods (assuming that they want
> to
> > > use
> > > > > this
> > > > > > > new
> > > > > > > > > > > > feature)
> > > > > > > > > > > > > > > versus
> > > > > > > > > > > > > > > > > >> using
> > > > > > > > > > > > > > > > > >> > a
> > > > > > > > > > > > > > > > > >> > > > try-catch block around
> `SinkRecord`
> > > > access
> > > > > > > > > methods?
> > > > > > > > > > In
> > > > > > > > > > > > > both
> > > > > > > > > > > > > > > > > cases, a
> > > > > > > > > > > > > > > > > >> > > > connector developer would need to
> > > write
> > > > > > > > additional
> > > > > > > > > > > code
> > > > > > > > > > > > in
> > > > > > > > > > > > > > > order
> > > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > > >> > > ensure
> > > > > > > > > > > > > > > > > >> > > > that their connector continues
> > working
> > > > > with
> > > > > > > > older
> > > > > > > > > > > > Connect
> > > > > > > > > > > > > > > > > runtimes.
> > > > > > > > > > > > > > > > > >> > > > Furthermore, we would probably
> need
> > to
> > > > > > > carefully
> > > > > > > > > > > > document
> > > > > > > > > > > > > > how
> > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > > >> > > > implementation for the older `put`
> > > > method
> > > > > > > should
> > > > > > > > > > look
> > > > > > > > > > > > like
> > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > > >> > connectors
> > > > > > > > > > > > > > > > > >> > > > that want to use this new
> feature. I
> > > > think
> > > > > > the
> > > > > > > > > > > advantage
> > > > > > > > > > > > > of
> > > > > > > > > > > > > > > > going
> > > > > > > > > > > > > > > > > >> with
> > > > > > > > > > > > > > > > > >> > > the
> > > > > > > > > > > > > > > > > >> > > > proposed approach in the KIP is
> that
> > > it
> > > > > > > wouldn't
> > > > > > > > > > > require
> > > > > > > > > > > > > > extra
> > > > > > > > > > > > > > > > > >> > > book-keeping
> > > > > > > > > > > > > > > > > >> > > > (the Map<SinkRecord,
> > > > > > > > > > > > > > > > > >> > > > TopicPartition> in
> `WorkerSinkTask`
> > in
> > > > > your
> > > > > > > > > proposed
> > > > > > > > > > > > > > approach)
> > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > >> also
> > > > > > > > > > > > > > > > > >> > > the
> > > > > > > > > > > > > > > > > >> > > > fact that the try-catch based
> logic
> > is
> > > > an
> > > > > > > > already
> > > > > > > > > > > > > > established
> > > > > > > > > > > > > > > > > >> pattern
> > > > > > > > > > > > > > > > > >> > > > through
> > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-610%3A+Error+Reporting+in+Sink+Connectors
> > > > > > > > > > > > > > > > > >> > > > and other KIPs which added methods
> > to
> > > > > > > > source/sink
> > > > > > > > > > > > > > > connector/task
> > > > > > > > > > > > > > > > > >> > > contexts.
> > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > >> > > > Let me know if you still feel that
> > > > having
> > > > > a
> > > > > > > new
> > > > > > > > > > > > overloaded
> > > > > > > > > > > > > > put
> > > > > > > > > > > > > > > > > >> method
> > > > > > > > > > > > > > > > > >> > is
> > > > > > > > > > > > > > > > > >> > > a
> > > > > > > > > > > > > > > > > >> > > > cleaner solution and I'd be happy
> to
> > > > > > > reconsider!
> > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > >> > > > Thanks,
> > > > > > > > > > > > > > > > > >> > > > Yash
> > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > >> > > > On Thu, Sep 22, 2022 at 11:18 PM
> > > Randall
> > > > > > > Hauch <
> > > > > > > > > > > > > > > > rhauch@gmail.com>
> > > > > > > > > > > > > > > > > >> > wrote:
> > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > >> > > > > Hi, Yash. Thanks for picking up
> > this
> > > > KIP
> > > > > > and
> > > > > > > > > > > > discussion.
> > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > >> > > > > The KIP includes this rejected
> > > > > > alternative:
> > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > >> > > > > > 4. Update SinkTask.put in any
> > way
> > > to
> > > > > > pass
> > > > > > > > the
> > > > > > > > > > new
> > > > > > > > > > > > > > > > information
> > > > > > > > > > > > > > > > > >> > outside
> > > > > > > > > > > > > > > > > >> > > > > > SinkRecord (e.g. a Map or a
> > > derived
> > > > > > class)
> > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > >> > > > > >    -
> > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > >> > > > > >    Much more disruptive change
> > > > without
> > > > > > > > > > > considerable
> > > > > > > > > > > > > pros
> > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > >> > > > > One advantage about doing this
> is
> > > that
> > > > > > sink
> > > > > > > > > > > connector
> > > > > > > > > > > > > > > > > >> implementations
> > > > > > > > > > > > > > > > > >> > > can
> > > > > > > > > > > > > > > > > >> > > > > more easily implement two
> > different
> > > > > > > "put(...)"
> > > > > > > > > > > methods
> > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > handle
> > > > > > > > > > > > > > > > > >> > > running
> > > > > > > > > > > > > > > > > >> > > > in
> > > > > > > > > > > > > > > > > >> > > > > a variety of runtimes, without
> > > having
> > > > to
> > > > > > use
> > > > > > > > > > > try-catch
> > > > > > > > > > > > > > logic
> > > > > > > > > > > > > > > > > >> around
> > > > > > > > > > > > > > > > > >> > the
> > > > > > > > > > > > > > > > > >> > > > > newer SinkRecord access methods.
> > > That
> > > > > > latter
> > > > > > > > > logic
> > > > > > > > > > > can
> > > > > > > > > > > > > get
> > > > > > > > > > > > > > > > quite
> > > > > > > > > > > > > > > > > >> > ugly.
> > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > >> > > > > For example, the existing `put`
> > > method
> > > > > has
> > > > > > > > this
> > > > > > > > > > > > > signature:
> > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > >> > > > > public abstract void
> > > > > > > > put(Collection<SinkRecord>
> > > > > > > > > > > > > records);
> > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > >> > > > > If we added an overloaded method
> > > that
> > > > > > passed
> > > > > > > > in
> > > > > > > > > a
> > > > > > > > > > > map
> > > > > > > > > > > > of
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > old
> > > > > > > > > > > > > > > > > >> > > > > topic+partition for each record
> > (and
> > > > > > defined
> > > > > > > > the
> > > > > > > > > > > > absence
> > > > > > > > > > > > > > of
> > > > > > > > > > > > > > > an
> > > > > > > > > > > > > > > > > >> entry
> > > > > > > > > > > > > > > > > >> > as
> > > > > > > > > > > > > > > > > >> > > > > having an unchanged topic and
> > > > > partition):
> > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > >> > > > > public void
> > > put(Collection<SinkRecord>
> > > > > > > > records,
> > > > > > > > > > > > > > > > Map<SinkRecord,
> > > > > > > > > > > > > > > > > >> > > > > TopicPartition>
> > > > updatedTopicPartitions)
> > > > > {
> > > > > > > > > > > > > > > > > >> > > > > put(records);
> > > > > > > > > > > > > > > > > >> > > > > }
> > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > >> > > > > then a `SinkTask` implementation
> > > that
> > > > > > wants
> > > > > > > to
> > > > > > > > > use
> > > > > > > > > > > > this
> > > > > > > > > > > > > > new
> > > > > > > > > > > > > > > > > >> feature
> > > > > > > > > > > > > > > > > >> > > could
> > > > > > > > > > > > > > > > > >> > > > > simply implement both methods:
> > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > >> > > > > public void
> > > put(Collection<SinkRecord>
> > > > > > > > records)
> > > > > > > > > {
> > > > > > > > > > > > > > > > > >> > > > > // Running in an older runtime,
> so
> > > no
> > > > > > > tracking
> > > > > > > > > of
> > > > > > > > > > > > > > > SMT-modified
> > > > > > > > > > > > > > > > > >> topic
> > > > > > > > > > > > > > > > > >> > > > names
> > > > > > > > > > > > > > > > > >> > > > > or partitions
> > > > > > > > > > > > > > > > > >> > > > > put(records, Map.of());
> > > > > > > > > > > > > > > > > >> > > > > }
> > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > >> > > > > public void
> > > put(Collection<SinkRecord>
> > > > > > > > records,
> > > > > > > > > > > > > > > > Map<SinkRecord,
> > > > > > > > > > > > > > > > > >> > > > > TopicPartition>
> > > > updatedTopicPartitions)
> > > > > {
> > > > > > > > > > > > > > > > > >> > > > > // real logic here
> > > > > > > > > > > > > > > > > >> > > > > }
> > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > >> > > > > This seems a lot easier than
> > having
> > > to
> > > > > use
> > > > > > > > > > try-catch
> > > > > > > > > > > > > > logic,
> > > > > > > > > > > > > > > > yet
> > > > > > > > > > > > > > > > > >> still
> > > > > > > > > > > > > > > > > >> > > > > allows sink connectors to
> utilize
> > > the
> > > > > new
> > > > > > > > > > > > functionality
> > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > > still
> > > > > > > > > > > > > > > > > >> > work
> > > > > > > > > > > > > > > > > >> > > > with
> > > > > > > > > > > > > > > > > >> > > > > older Connect runtimes.
> > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > >> > > > > WDYT?
> > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > >> > > > > Randall
> > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > >> > > > > On Thu, Sep 8, 2022 at 7:03 AM
> > Yash
> > > > > Mayya
> > > > > > <
> > > > > > > > > > > > > > > > yash.mayya@gmail.com
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > >> > > wrote:
> > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > >> > > > > > Hi all,
> > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > >> > > > > > I would like to (re)start a
> new
> > > > > > discussion
> > > > > > > > > > thread
> > > > > > > > > > > on
> > > > > > > > > > > > > > > KIP-793
> > > > > > > > > > > > > > > > > >> (Kafka
> > > > > > > > > > > > > > > > > >> > > > > > Connect) which proposes some
> > > > additions
> > > > > > to
> > > > > > > > the
> > > > > > > > > > > public
> > > > > > > > > > > > > > > > > SinkRecord
> > > > > > > > > > > > > > > > > >> > > > interface
> > > > > > > > > > > > > > > > > >> > > > > > in order to support topic
> > mutating
> > > > > SMTs
> > > > > > > for
> > > > > > > > > sink
> > > > > > > > > > > > > > > connectors
> > > > > > > > > > > > > > > > > >> that do
> > > > > > > > > > > > > > > > > >> > > > their
> > > > > > > > > > > > > > > > > >> > > > > > own offset tracking.
> > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > >> > > > > > Links:
> > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > >> > > > > > KIP:
> > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=191336830
> > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > >> > > > > > Older discussion thread:
> > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > >
> > > > > > >
> https://lists.apache.org/thread/00kcth6057jdcsyzgy1x8nb2s1cymy8h
> > > > > > > > ,
> > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > >
> > > > > > >
> https://lists.apache.org/thread/rzqkm0q5y5v3vdjhg8wqppxbkw7nyopj
> > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > >> > > > > > Jira:
> > > > > > > > > > > > > https://issues.apache.org/jira/browse/KAFKA-13431
> > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > >> > > > > > Thanks,
> > > > > > > > > > > > > > > > > >> > > > > > Yash
> > > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
>

Re: [DISCUSS] KIP-793: Sink Connectors: Support topic-mutating SMTs for async connectors (preCommit users)

[Greg Harris <gr...@aiven.io.INVALID>]

Yash,

> 'm not sure I follow - are you asking about how the tests will be updated
post this change or about how upgrades will look like for clusters in
production?

Currently the AK tests have a lot of calls to, for example, new
SinkRecord(String topic, int partition, Schema keySchema, Object key,
Schema valueSchema, Object value, long kafkaOffset), a constructor without
the original T/P/O values. I assumed that for backwards compatibility these
constructors would still be usable in new runtimes.
I imagine that there are also tests in downstream projects which make use
of these constructors, whenever a Transform, Predicate, or Task is tested
without a corresponding Converter. My question was about what values are
chosen for the original T/P/O methods when these constructors are used
after an upgrade to the latest connect-api.

> There shouldn't be any difference in behavior here - the framework will
add
the original T/P/O metadata to the record after the entire transformation
chain has been applied and just before sending the record to the task for
processing. The KIP doesn't propose that transformations themselves should
also be able to retrieve original T/P/O information for a sink record.

The KIP includes this: "Note that while the record's offset can't be
modified via the standard SinkRecord::newRecord methods that SMTs are
expected to use, SinkRecord has public constructors that would allow SMTs
to return records with modified offsets. This is why the proposed changes
include a new SinkRecord::originalKafkaOffset method as well."
In order to use the new or old SinkRecord constructors outside of the
newRecord methods, SMTs will downcast the previous record and may access
the original T/P/O methods. They may or may not forward this to the next
SMT, and they may or may not use it in their own computation.
Since this is acknowledged as a possible implementation, I was just asking
about when one SMT changes the original T/P/O, what should later SMTs and
predicates see from the original T/P/O methods?
If you inject the original T/P/O only before and after the chain, SMTs
after an SMT which changes the original T/P/O will see whatever the earlier
SMT emitted. Is this intentional, or should this be avoided?
For existing SMTs use the SinkRecord constructor, either directly or via
subclasses of ConnectRecord, they will drop the original T/P/O and fall
back to the logic from question (1).

> The rejected alternative basically says that we can't do a
deterministic mapping from virtual coordinates to physical coordinates
without doing a lot of book-keeping.

I suppose there is a possible implementation of metadata book-keeping which
provides a reasonable system of virtual coordinates, it just ended up
equivalent to hydrating intermediate topics to compute a consistent record
ordering. I wasn't convinced by calling it "book-keeping" since i've seen
that phrase used to disregard much less complicated state management, and
had to see exactly where that solution becomes unreasonable.

Thanks,
Greg

On Sun, Mar 12, 2023 at 6:30 AM Yash Mayya <ya...@gmail.com> wrote:

> Hi Greg,
>
> Thanks for the detailed review!
>
> > What is the expected state/behavior for SinkRecords
> > which do not have original T/P/O information after the
> > upgrade? Just browsing, it appears that tests make
> > extensive use of the existing public SinkRecord
> > constructors  for both Transformations and Connectors.
>
> I'm not sure I follow - are you asking about how the tests will be updated
> post this change or about how upgrades will look like for clusters in
> production? For the latter, we won't have to worry about sink records
> without original T/P/O information at all once a cluster is fully rolled
> and we will make it (hopefully) abundantly clear that connectors need to
> account for missing original T/P/O getter methods if they expect to be
> deployed on older Connect runtimes.
>
> > What is the expected behavior for Transformation
> > implementations which do not use the newRecord
> > methods and instead use public SinkRecord constructors?
> > The KIP mentions this as a justification for the
> > originalKafkaOffset method, but if existing implementations
> > are using the existing constructors, those constructors won't
> > forward the original T/P/O information to later transforms or
> > the task.
>
> There shouldn't be any difference in behavior here - the framework will add
> the original T/P/O metadata to the record after the entire transformation
> chain has been applied and just before sending the record to the task for
> processing. The KIP doesn't propose that transformations themselves should
> also be able to retrieve original T/P/O information for a sink record.
>
> > This reasoning and the KIP design seems to imply that the
> > connector is better equipped to solve this problem than the
> > framework, but the stated reasons are not convincing for me.
>
> This was added to the KIP by the original author, but I don't think the
> intention was to imply that the connector is better equipped to solve this
> problem than the framework. The intention is to provide complete
> information to the connector ("physical" and "virtual coordinates" instead
> of the currently incomplete "virtual coordinates" as you've termed it) so
> that connectors can use the virtual coordinates for writing data to the
> sink system and physical coordinates for offset reporting back to the
> framework. The rejected alternative basically says that we can't do a
> deterministic mapping from virtual coordinates to physical coordinates
> without doing a lot of book-keeping.
>
> I agree with the rest of your analysis on the tradeoffs between the
> proposed approach versus the seemingly more attractive approach of handling
> everything purely in the framework and only exposing "virtual coordinates"
> to the connectors. I think the biggest thorn here is maintaining backward
> compatibility with the considerable ecosystem of existing connectors which
> is something Connect has always been burdened by.
>
> Thanks,
> Yash
>
> On Wed, Mar 8, 2023 at 6:54 AM Greg Harris <gr...@aiven.io.invalid>
> wrote:
>
> > Hi Yash,
> >
> > I always use this issue as an example of a bug being caused by design
> > rather than by implementation error, and once it's fixed I'll need to
> find
> > something else to talk about :)
> > So glad to see this get fixed!
> >
> > I'll chime in to support some of the earlier discussions that seem to
> have
> > been resolved:
> >
> > 1. With respect to SinkRecord methods vs an overloaded put(): I agree
> with
> > the current design but I justify it a little bit differently than has
> > already been discussed.
> > If we were designing this interface on day 1 without backwards
> > compatibility in mind, which design would make more sense? Or for a
> > different framing: In the future when old runtimes and connectors are
> > retired and the old interfaces are removed, which design is going to look
> > more strange and unmotivated?
> > Applied to this design decision, I would say that the original T/P/O are
> > properties of a single SinkRecord and make sense as getters, and it would
> > be strange to store them in an auxiliary map.
> >
> > 2. Following up this change with a compatibility library to make the
> > interface easier to use is the right choice to make here. This change
> > should be focused on correctness in allowing developers to fix the
> > incompatibility and we can be concerned with coming up with a more
> > ergonomic solution in the compatibility library.
> > The API should be focused on generality, correctness, and performance
> > because those cannot be worked-around after the fact. Connector
> > implementations and/or libraries can be concerned with trading off some
> > generality and/or performance for ease-of-use.
> >
> > 3. I think that the difference in behavior of the new open/close methods
> as
> > compared to the old methods is significant, and requires good
> documentation
> > to help connector developers avoid lazy and incorrect migrations. I am
> > happy to have that addressed in code review after the KIP is approved.
> >
> > I had some questions:
> >
> > 4. What is the expected state/behavior for SinkRecords which do not have
> > original T/P/O information after the upgrade? Just browsing, it appears
> > that tests make extensive use of the existing public SinkRecord
> > constructors for both Transformations and Connectors.
> >
> > 5. What is the expected behavior for Transformation implementations which
> > do not use the newRecord methods and instead use public SinkRecord
> > constructors? The KIP mentions this as a justification for the
> > originalKafkaOffset method, but if existing implementations are using the
> > existing constructors, those constructors won't forward the original
> T/P/O
> > information to later transforms or the task.
> >
> > For the last few points, I want to discuss this rejected alternative:
> >
> > > Address the offsets problem entirely within the framework, doing some
> > kind of mapping from the transformed topic back to the original topic.
> > > * This would only work in the cases where there’s no overlap between
> the
> > transformed topic names, but would break for the rest of the
> > transformations (e.g. static transformation, topic = “a”).
> > > * Even if we wanted to limit the support to those cases, it would
> require
> > considerable bookkeeping to add a validation to verify that the
> > transformation chain adheres to that expectation (and fail fast if it
> > doesn’t).
> >
> > 6. This reasoning and the KIP design seems to imply that the connector is
> > better equipped to solve this problem than the framework, but the stated
> > reasons are not convincing for me.
> > * A static transformation still causes an offset collision in the
> connector
> > * The connector is not permitted to see the transformation chain to do
> any
> > fail-fast assertions
> >
> > Suppose we were to think of the records at the end of the transformation
> > chain as being in "virtual partitions" with "virtual offsets".
> > For example, with identity-routing SMTs, the virtual coordinates are
> > exactly the same as the underlying physical coordinates. For 1-1 renames,
> > each virtual topic would be the renamed topic corresponding to the
> > underlying topic. For fan-out from one topic to multiple virtual topics,
> > virtual offsets would use the underlying kafka offsets with gaps for
> > records going to other virtual partitions. Virtual topics with dropped
> > records have similar gaps in the offsets.
> > Currently, these virtual coordinates are passed into the connector via
> > SinkTask::put, but SinkTask::open/close/preCommit and
> > SinkTaskContext::assignment/offsets/pause/resume all use physical
> > coordinates.
> > This proposal patches put,open, and close to have both physical and
> virtual
> > coordinates, but leaves the other methods with physical coordinates.
> After
> > this proposal, connectors would be intentionally made aware of the
> > distinction between physical and virtual coordinates, and manage their
> own
> > bookkeeping for the two systems.
> >
> > To avoid that connector logic, we could use virtual coordinates in all
> > connector calls, never revealing that they are different from the
> physical
> > coordinates. There's a whole design shopping list that we'd need:
> > * Renumbering mechanism for disambiguating and making virtual offsets
> > monotonic in the case of topic/partition collisions
> > * Data structure and strategy for translating virtual offsets back to
> > physical offsets
> > * New limits on SinkTaskContext::offsets() calls to prevent rewinding
> > before the latest commit
> > * Backwards compatibility and upgrade design
> >
> > 7. This alternative was very appealing to me, because the strength of a
> > plugin framework is the composability of different components. Among a
> > collection of N connectors and M transforms, it should ideally only take
> > N + M work to understand how the components combine to build the whole.
> > However, once you start adding special cases to some plugins to support
> > interactions with others, the whole system can take N * M work to
> > understand. From a complexity standpoint, it would be very good for the
> > framework to solve this in a way which was connector-agnostic.
> > The current design compromises the logical isolation of the plugins
> > slightly, but they can collapse offsets very memory-efficiently, and
> re-use
> > the existing raw coordinate functions and keep everything else backwards
> > compatible. After deriving all of the above, I think that's a reasonable
> > tradeoff to make.
> >
> > Thanks,
> > Greg
> >
> > On Tue, Feb 21, 2023 at 10:17 AM Chris Egerton <ch...@aiven.io.invalid>
> > wrote:
> >
> > > Hi Yash,
> > >
> > > We'll probably want to make a few tweaks to the Javadocs for the new
> > > methods (I'm imagining that notes on compatibility with older versions
> > will
> > > be required), but I believe what's proposed in the KIP is good enough
> to
> > > approve with the understanding that it may not exactly match what gets
> > > implemented/merged.
> > >
> > > LGTM, thanks again for the KIP!
> > >
> > > Cheers,
> > >
> > > Chris
> > >
> > > On Tue, Feb 21, 2023 at 12:18 PM Yash Mayya <ya...@gmail.com>
> > wrote:
> > >
> > > > Hi Chris,
> > > >
> > > > > we might try to introduce a framework-level configuration
> > > > > property to dictate which of the pre-transform and post-transform
> > > > > topic partitions are used for the fallback call to the single-arg
> > > > > variant if a task class has not overridden the multi-arg variant
> > > >
> > > > Thanks for the explanation and I agree that this will be a tad bit
> too
> > > > convoluted. :)
> > > >
> > > > Please do let me know if you'd like any further amendments to the
> KIP!
> > > >
> > > > Thanks,
> > > > Yash
> > > >
> > > > On Tue, Feb 21, 2023 at 8:42 PM Chris Egerton
> <chrise@aiven.io.invalid
> > >
> > > > wrote:
> > > >
> > > > > Hi Yash,
> > > > >
> > > > > I think the use case for pre-transform TPO coordinates (and topic
> > > > partition
> > > > > writers created/destroyed in close/open) tends to boil down to
> > > > exactly-once
> > > > > semantics, where it's desirable to preserve the guarantees that
> Kafka
> > > > > provides (every record has a unique TPO trio, and records are
> ordered
> > > by
> > > > > offset within a topic partition).
> > > > >
> > > > > It's my understanding that this approach is utilized in several
> > > > connectors
> > > > > out there today, and it might break these connectors to start using
> > the
> > > > > post-transform topic partitions automatically in their open/close
> > > > methods.
> > > > >
> > > > > If we want to get really fancy with this and try to obviate or at
> > least
> > > > > reduce the need for per-connector code changes, we might try to
> > > > introduce a
> > > > > framework-level configuration property to dictate which of the
> > > > > pre-transform and post-transform topic partitions are used for the
> > > > fallback
> > > > > call to the single-arg variant if a task class has not overridden
> the
> > > > > multi-arg variant. But I think this is going a bit too far and
> would
> > > > prefer
> > > > > to keep things simple(r) for now.
> > > > >
> > > > > Cheers,
> > > > >
> > > > > Chris
> > > > >
> > > > >
> > > > > On Sun, Feb 19, 2023 at 2:34 AM Yash Mayya <ya...@gmail.com>
> > > wrote:
> > > > >
> > > > > > Hi Chris,
> > > > > >
> > > > > > > I was actually envisioning something like `void
> > > > > > > open(Collection<TopicPartition> originalPartitions,
> > > > > > > Collection<TopicPartition> transformedPartitions)`
> > > > > >
> > > > > > Ah okay, this does make a lot more sense. Sorry, I think I
> > > > misunderstood
> > > > > > you earlier. I do agree with you that this seems better than
> > > splitting
> > > > it
> > > > > > off into two new sets of open / close methods from a complexity
> > > > > standpoint.
> > > > > >
> > > > > > > Plus, if a connector is intentionally designed to use
> > > > > > > pre-transformation topic partitions in its open/close
> > > > > > > methods, wouldn't we just be trading one form of the
> > > > > > >  problem for another by making this switch?
> > > > > >
> > > > > > On thinking about this a bit more, I'm not so convinced that we
> > need
> > > to
> > > > > > expose the pre-transform / original topic partitions in the new
> > open
> > > /
> > > > > > close methods. The purpose of the open / close methods is to
> allow
> > > sink
> > > > > > tasks to allocate and deallocate resources for each topic
> partition
> > > > > > assigned to the task and the purpose of topic-mutating SMTs is to
> > > > > > essentially modify the source topic name from the point of view
> of
> > > the
> > > > > sink
> > > > > > connector. Why would a sink connector ever need to or want to
> > > allocate
> > > > > > resources for pre-transform topic partitions? Is the argument
> here
> > > that
> > > > > > since we'll be exposing both the pre-transform and post-transform
> > > topic
> > > > > > partitions per record, we should also expose the same info via
> > open /
> > > > > close
> > > > > > and allow sink connector implementations to disregard
> > topic-mutating
> > > > SMTs
> > > > > > completely if they wanted to?
> > > > > >
> > > > > > Either way, I've gone ahead and updated the KIP to reflect all of
> > > > > > our previous discussion here since it had become quite outdated.
> > I've
> > > > > also
> > > > > > updated the KIP title from "Sink Connectors: Support
> topic-mutating
> > > > SMTs
> > > > > > for async connectors (preCommit users)" to "Allow sink connectors
> > to
> > > be
> > > > > > used with topic-mutating SMTs" since the improvements to the
> open /
> > > > close
> > > > > > mechanism doesn't pertain only to asynchronous sink connectors.
> The
> > > new
> > > > > KIP
> > > > > > URL is:
> > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-793%3A+Allow+sink+connectors+to+be+used+with+topic-mutating+SMTs
> > > > > >
> > > > > >
> > > > > > Thanks,
> > > > > > Yash
> > > > > >
> > > > > > On Tue, Feb 14, 2023 at 11:39 PM Chris Egerton
> > > <chrise@aiven.io.invalid
> > > > >
> > > > > > wrote:
> > > > > >
> > > > > > > Hi Yash,
> > > > > > >
> > > > > > > I was actually envisioning something like `void
> > > > > > > open(Collection<TopicPartition>
> > > > > > > originalPartitions, Collection<TopicPartition>
> > > > transformedPartitions)`,
> > > > > > > since we already convert and transform each batch of records
> that
> > > we
> > > > > poll
> > > > > > > from the sink task's consumer en masse, meaning we could
> discover
> > > > > several
> > > > > > > new transformed partitions in between consecutive calls to
> > > > > SinkTask::put.
> > > > > > >
> > > > > > > It's also worth noting that we'll probably want to deprecate
> the
> > > > > existing
> > > > > > > open/close methods, at which point keeping one non-deprecated
> > > variant
> > > > > of
> > > > > > > each seems more appealing and less complex than keeping two.
> > > > > > >
> > > > > > > Honestly though, I think we're both on the same page enough
> that
> > I
> > > > > > wouldn't
> > > > > > > object to either approach. We've probably reached the
> saturation
> > > > point
> > > > > > for
> > > > > > > ROI here and as long as we provide developers a way to get the
> > > > > > information
> > > > > > > they need from the runtime and take care to add Javadocs and
> > update
> > > > our
> > > > > > > docs page (possibly including the connector development
> > > quickstart),
> > > > it
> > > > > > > should be fine.
> > > > > > >
> > > > > > > At this point, it might be worth updating the KIP based on
> recent
> > > > > > > discussion so that others can see the latest proposal, and we
> can
> > > > both
> > > > > > take
> > > > > > > a look and make sure everything looks good enough before
> opening
> > a
> > > > vote
> > > > > > > thread.
> > > > > > >
> > > > > > > Finally, I think you make a convincing case for a time-based
> > > eviction
> > > > > > > policy. I wasn't thinking about the fairly common SMT pattern
> of
> > > > > > deriving a
> > > > > > > topic name from, e.g., a record field or header.
> > > > > > >
> > > > > > > Cheers,
> > > > > > >
> > > > > > > Chris
> > > > > > >
> > > > > > > On Tue, Feb 14, 2023 at 11:42 AM Yash Mayya <
> > yash.mayya@gmail.com>
> > > > > > wrote:
> > > > > > >
> > > > > > > > Hi Chris,
> > > > > > > >
> > > > > > > > > Plus, if a connector is intentionally designed to
> > > > > > > > > use pre-transformation topic partitions in its
> > > > > > > > > open/close methods, wouldn't we just be trading
> > > > > > > > > one form of the problem for another by making this
> > > > > > > > > switch?
> > > > > > > >
> > > > > > > > Thanks, this makes sense, and given that the KIP already
> > > proposes a
> > > > > way
> > > > > > > for
> > > > > > > > sink connector implementations to distinguish between
> > > pre-transform
> > > > > and
> > > > > > > > post-transform topics per record, I think I'm convinced that
> > > going
> > > > > with
> > > > > > > new
> > > > > > > > `open()` / `close()` methods is the right approach. However,
> I
> > > > still
> > > > > > feel
> > > > > > > > like having overloaded methods will make it a lot less
> > > unintuitive
> > > > > > given
> > > > > > > > that the two sets of methods would be different in terms of
> > when
> > > > > > they're
> > > > > > > > called and what arguments they are passed (also I'm presuming
> > > that
> > > > > the
> > > > > > > > overloaded methods you're prescribing will only have a single
> > > > > > > > `TopicPartition` rather than a `Collection<TopicPartition>`
> as
> > > > their
> > > > > > > > parameters). I guess my concern is largely around the fact
> that
> > > it
> > > > > > won't
> > > > > > > be
> > > > > > > > possible to distinguish between the overloaded methods' use
> > cases
> > > > > just
> > > > > > > from
> > > > > > > > the method signatures. I agree that naming is going to be
> > > difficult
> > > > > > here,
> > > > > > > > but I think that having two sets of `SinkTask::openXyz` /
> > > > > > > > `SinkTask::closeXyz` methods will be less complicated to
> > > understand
> > > > > > from
> > > > > > > a
> > > > > > > > connector developer perspective (as compared to overloaded
> > > methods
> > > > > with
> > > > > > > > only differing documentation). Of your suggested options, I
> > think
> > > > > > > > `openPreTransform` / `openPostTransform` are the most
> > > > comprehensible
> > > > > > > ones.
> > > > > > > >
> > > > > > > > > BTW, I wouldn't say that we can't make assumptions
> > > > > > > > > about the relationships between pre- and
> post-transformation
> > > > > > > > >  topic partitions.
> > > > > > > >
> > > > > > > > I meant that the framework wouldn't be able to
> > deterministically
> > > > know
> > > > > > > when
> > > > > > > > to close a post-transform topic partition given that SMTs
> could
> > > use
> > > > > > > > per-record data / metadata to manipulate the topic names as
> and
> > > how
> > > > > > > > required (which supports the suggestion to use an eviction
> > policy
> > > > > based
> > > > > > > > mechanism to call SinkTask::close for post-transform topic
> > > > > partitions).
> > > > > > > >
> > > > > > > > > We might utilize a policy that assumes a deterministic
> > > > > > > > > mapping from the former to the latter, for example.
> > > > > > > >
> > > > > > > > Wouldn't this be making the assumption that SMTs only use the
> > > topic
> > > > > > name
> > > > > > > > itself and no other data / metadata while computing the new
> > topic
> > > > > name?
> > > > > > > Are
> > > > > > > > you suggesting that since this assumption could work for a
> > > majority
> > > > > of
> > > > > > > > SMTs, it might be more efficient overall in terms of reducing
> > the
> > > > > > number
> > > > > > > of
> > > > > > > > "false-positive" calls to `SinkTask::closePostTransform` (and
> > > we'll
> > > > > > also
> > > > > > > be
> > > > > > > > able to call `SinkTask::closePostTransform` immediately after
> > > topic
> > > > > > > > partitions are revoked from the consumer)? I was thinking
> > > something
> > > > > > more
> > > > > > > > generic along the lines of a simple time based eviction
> policy
> > > that
> > > > > > > > wouldn't be making any assumptions regarding the SMT
> > > > implementations.
> > > > > > > > Either way, I do like your earlier suggestion of keeping this
> > > logic
> > > > > > > > internal and not painting ourselves into a corner by
> promising
> > > any
> > > > > > > > particular behavior in the KIP.
> > > > > > > >
> > > > > > > > Thanks,
> > > > > > > > Yash
> > > > > > > >
> > > > > > > > On Tue, Feb 14, 2023 at 1:08 AM Chris Egerton
> > > > > <chrise@aiven.io.invalid
> > > > > > >
> > > > > > > > wrote:
> > > > > > > >
> > > > > > > > > Hi Yash,
> > > > > > > > >
> > > > > > > > > I think the key difference between adding methods/overloads
> > > > related
> > > > > > to
> > > > > > > > > SinkTask::open/SinkTask::close and SinkTask::put is that
> this
> > > > isn't
> > > > > > > > > auxiliary information that may or may not be useful to
> > > connector
> > > > > > > > > developers. It's actually critical for them to understand
> the
> > > > > > > difference
> > > > > > > > > between the two concepts here, even if they look very
> > similar.
> > > > And
> > > > > > > yes, I
> > > > > > > > > do believe that switching from pre-transform to
> > post-transform
> > > > > topic
> > > > > > > > > partitions is too big a change in behavior here. Plus, if a
> > > > > connector
> > > > > > > is
> > > > > > > > > intentionally designed to use pre-transformation topic
> > > partitions
> > > > > in
> > > > > > > its
> > > > > > > > > open/close methods, wouldn't we just be trading one form of
> > the
> > > > > > problem
> > > > > > > > for
> > > > > > > > > another by making this switch?
> > > > > > > > >
> > > > > > > > > One possible alternative to overloading the existing
> methods
> > is
> > > > to
> > > > > > > split
> > > > > > > > > SinkTask::open into openOriginal (or possibly openPhysical
> or
> > > > > > > > > openPreTransform) and openTransformed (or openLogical or
> > > > > > > > > openPostTransform), with a similar change for
> > SinkTask::close.
> > > > The
> > > > > > > > default
> > > > > > > > > implementation for SinkTask::openOriginal can be to call
> > > > > > > SinkTask::open,
> > > > > > > > > and the same can go for SinkTask::close. However, I prefer
> > > > > > overloading
> > > > > > > > the
> > > > > > > > > existing methods since this alternative increases
> complexity
> > > and
> > > > > none
> > > > > > > of
> > > > > > > > > the names are very informative.
> > > > > > > > >
> > > > > > > > > BTW, I wouldn't say that we can't make assumptions about
> the
> > > > > > > > relationships
> > > > > > > > > between pre- and post-transformation topic partitions. We
> > might
> > > > > > > utilize a
> > > > > > > > > policy that assumes a deterministic mapping from the former
> > to
> > > > the
> > > > > > > > latter,
> > > > > > > > > for example. The distinction I'd draw is that the
> assumptions
> > > we
> > > > > make
> > > > > > > can
> > > > > > > > > and probably should favor some cases in terms of
> performance
> > > > (i.e.,
> > > > > > > > > reducing the number of unnecessary calls to close/open
> over a
> > > > given
> > > > > > > sink
> > > > > > > > > task's lifetime), but should not lead to guaranteed
> resource
> > > > leaks
> > > > > or
> > > > > > > > > failure to obey API contract in any cases.
> > > > > > > > >
> > > > > > > > > Cheers,
> > > > > > > > >
> > > > > > > > > Chris
> > > > > > > > >
> > > > > > > > > On Mon, Feb 13, 2023 at 10:54 AM Yash Mayya <
> > > > yash.mayya@gmail.com>
> > > > > > > > wrote:
> > > > > > > > >
> > > > > > > > > > Hi Chris,
> > > > > > > > > >
> > > > > > > > > > > especially if connectors are intentionally designed
> > around
> > > > > > > > > > > original topic partitions instead of transformed ones.
> > > > > > > > > >
> > > > > > > > > > Ha, that's a good point and reminds me of Hyrum's Law [1]
> > :)
> > > > > > > > > >
> > > > > > > > > > > I think we have to provide connector developers with
> some
> > > > > > > > > > > way to differentiate between the two, but maybe
> there's a
> > > way
> > > > > > > > > > >  to do this that I haven't thought of yet
> > > > > > > > > >
> > > > > > > > > > I can't think of a better way to do this either; would
> > > invoking
> > > > > the
> > > > > > > > > > existing `SinkTask::open` and `SinkTask::close` methods
> > with
> > > > > > > > > post-transform
> > > > > > > > > > topic partitions instead of pre-transform topic
> partitions
> > > not
> > > > be
> > > > > > > > > > acceptable even in a minor / major AK release? I feel
> like
> > > the
> > > > > > > proposed
> > > > > > > > > > approach of adding overloaded `SinkTask::open` /
> > > > > `SinkTask::close`
> > > > > > > > > methods
> > > > > > > > > > to differentiate between pre-transform and post-transform
> > > topic
> > > > > > > > > partitions
> > > > > > > > > > has similar pitfalls to the idea of the overloaded
> > > > > `SinkTask::put`
> > > > > > > > method
> > > > > > > > > > we discarded earlier.
> > > > > > > > > >
> > > > > > > > > > > Either way, I'm glad that the general idea of a cache
> and
> > > > > > > > > > > eviction policy for SinkTask::close seem reasonable; if
> > > > > > > > > > > we decide to go this route, it might make sense for the
> > KIP
> > > > > > > > > > > to include an outline of one or more high-level
> > strategies
> > > > > > > > > > > we might take, but without promising any particular
> > > behavior
> > > > > > > > > > > beyond occasionally calling SinkTask::close for
> > > > post-transform
> > > > > > > > > > > topic partitions. I'm hoping that this logic can stay
> > > > internal,
> > > > > > > > > > > and by notpainting ourselves into a corner with the
> KIP,
> > we
> > > > > > > > > > > give ourselves leeway to tweak it in the future if
> > > necessary
> > > > > > > > > > > without filing another KIP or introducing a pluggable
> > > > > interface.
> > > > > > > > > >
> > > > > > > > > > Thanks, that's a good idea. Given the flexibility of
> SMTs,
> > > the
> > > > > > > > framework
> > > > > > > > > > can't really make any assumptions around topic partitions
> > > post
> > > > > > > > > > transformation nor does it have any way to definitively
> get
> > > any
> > > > > > such
> > > > > > > > > > information from transformations which is why the idea
> of a
> > > > cache
> > > > > > > with
> > > > > > > > an
> > > > > > > > > > eviction policy makes perfect sense!
> > > > > > > > > >
> > > > > > > > > > [1] - https://www.hyrumslaw.com/
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > Thanks,
> > > > > > > > > > Yash
> > > > > > > > > >
> > > > > > > > > > On Thu, Feb 9, 2023 at 9:38 PM Chris Egerton
> > > > > > <chrise@aiven.io.invalid
> > > > > > > >
> > > > > > > > > > wrote:
> > > > > > > > > >
> > > > > > > > > > > Hi Yash,
> > > > > > > > > > >
> > > > > > > > > > > > So it looks like with the current state of affairs,
> > sink
> > > > > tasks
> > > > > > > that
> > > > > > > > > > only
> > > > > > > > > > > instantiate writers in the SinkTask::open method (and
> > don't
> > > > do
> > > > > > the
> > > > > > > > lazy
> > > > > > > > > > > instantiation in SinkTask::put that you mentioned)
> might
> > > fail
> > > > > > when
> > > > > > > > used
> > > > > > > > > > > with topic/partition mutating SMTs even if they don't
> do
> > > any
> > > > > > > > > asynchronous
> > > > > > > > > > > processing?
> > > > > > > > > > >
> > > > > > > > > > > Yep, exactly 👍
> > > > > > > > > > >
> > > > > > > > > > > > What do you think about retaining just the existing
> > > methods
> > > > > > > > > > > but changing when they're called in the Connect
> runtime?
> > > For
> > > > > > > > instance,
> > > > > > > > > > > instead of calling SinkTask::open after partition
> > > assignment
> > > > > > post a
> > > > > > > > > > > consumer group rebalance, we could cache the currently
> > > "seen"
> > > > > > topic
> > > > > > > > > > > partitions (post transformation) and before each call
> to
> > > > > > > > SinkTask::put
> > > > > > > > > > > check whether there's any new "unseen" topic
> partitions,
> > > and
> > > > if
> > > > > > so
> > > > > > > > call
> > > > > > > > > > > SinkTask::open (and also update the cache of course).
> > > > > > > > > > >
> > > > > > > > > > > IMO the issue here is that it's a drastic change in
> > > behavior
> > > > to
> > > > > > > start
> > > > > > > > > > > invoking SinkTask::open and SinkTask::close with
> > > > post-transform
> > > > > > > topic
> > > > > > > > > > > partitions instead of pre-transform, especially if
> > > connectors
> > > > > are
> > > > > > > > > > > intentionally designed around original topic partitions
> > > > instead
> > > > > > of
> > > > > > > > > > > transformed ones. I think we have to provide connector
> > > > > developers
> > > > > > > > with
> > > > > > > > > > some
> > > > > > > > > > > way to differentiate between the two, but maybe
> there's a
> > > way
> > > > > to
> > > > > > do
> > > > > > > > > this
> > > > > > > > > > > that I haven't thought of yet. Interested to hear your
> > > > > thoughts.
> > > > > > > > > > >
> > > > > > > > > > > Either way, I'm glad that the general idea of a cache
> and
> > > > > > eviction
> > > > > > > > > policy
> > > > > > > > > > > for SinkTask::close seem reasonable; if we decide to go
> > > this
> > > > > > route,
> > > > > > > > it
> > > > > > > > > > > might make sense for the KIP to include an outline of
> one
> > > or
> > > > > more
> > > > > > > > > > > high-level strategies we might take, but without
> > promising
> > > > any
> > > > > > > > > particular
> > > > > > > > > > > behavior beyond occasionally calling SinkTask::close
> for
> > > > > > > > post-transform
> > > > > > > > > > > topic partitions. I'm hoping that this logic can stay
> > > > internal,
> > > > > > and
> > > > > > > > by
> > > > > > > > > > not
> > > > > > > > > > > painting ourselves into a corner with the KIP, we give
> > > > > ourselves
> > > > > > > > leeway
> > > > > > > > > > to
> > > > > > > > > > > tweak it in the future if necessary without filing
> > another
> > > > KIP
> > > > > or
> > > > > > > > > > > introducing a pluggable interface.
> > > > > > > > > > >
> > > > > > > > > > > Cheers,
> > > > > > > > > > >
> > > > > > > > > > > Chris
> > > > > > > > > > >
> > > > > > > > > > > On Thu, Feb 9, 2023 at 7:39 AM Yash Mayya <
> > > > > yash.mayya@gmail.com>
> > > > > > > > > wrote:
> > > > > > > > > > >
> > > > > > > > > > > > Hi Chris,
> > > > > > > > > > > >
> > > > > > > > > > > > Thanks for the feedback.
> > > > > > > > > > > >
> > > > > > > > > > > > 1) That's a fair point; while I did scan everything
> > > > publicly
> > > > > > > > > available
> > > > > > > > > > on
> > > > > > > > > > > > GitHub, you're right in that it won't cover all
> > possible
> > > > SMTs
> > > > > > > that
> > > > > > > > > are
> > > > > > > > > > > out
> > > > > > > > > > > > there. Thanks for the example use-case as well, I've
> > > > updated
> > > > > > the
> > > > > > > > KIP
> > > > > > > > > to
> > > > > > > > > > > add
> > > > > > > > > > > > the two new proposed methods.
> > > > > > > > > > > >
> > > > > > > > > > > > 2) So it looks like with the current state of
> affairs,
> > > sink
> > > > > > tasks
> > > > > > > > > that
> > > > > > > > > > > only
> > > > > > > > > > > > instantiate writers in the SinkTask::open method (and
> > > don't
> > > > > do
> > > > > > > the
> > > > > > > > > lazy
> > > > > > > > > > > > instantiation in SinkTask::put that you mentioned)
> > might
> > > > fail
> > > > > > > when
> > > > > > > > > used
> > > > > > > > > > > > with topic/partition mutating SMTs even if they don't
> > do
> > > > any
> > > > > > > > > > asynchronous
> > > > > > > > > > > > processing? Since they could encounter records in
> > > > > SinkTask::put
> > > > > > > > with
> > > > > > > > > > > > topics/partitions that they might not have created
> > > writers
> > > > > for.
> > > > > > > > > Thanks
> > > > > > > > > > > for
> > > > > > > > > > > > pointing this out, it's definitely another
> > > incompatibility
> > > > > that
> > > > > > > > needs
> > > > > > > > > > to
> > > > > > > > > > > be
> > > > > > > > > > > > called out and fixed. The overloaded method approach
> is
> > > > > > > > interesting,
> > > > > > > > > > but
> > > > > > > > > > > > comes with the caveat of yet more new methods that
> will
> > > > need
> > > > > to
> > > > > > > be
> > > > > > > > > > > > implemented by existing connectors if they want to
> make
> > > use
> > > > > of
> > > > > > > this
> > > > > > > > > new
> > > > > > > > > > > > functionality. What do you think about retaining just
> > the
> > > > > > > existing
> > > > > > > > > > > methods
> > > > > > > > > > > > but changing when they're called in the Connect
> > runtime?
> > > > For
> > > > > > > > > instance,
> > > > > > > > > > > > instead of calling SinkTask::open after partition
> > > > assignment
> > > > > > > post a
> > > > > > > > > > > > consumer group rebalance, we could cache the
> currently
> > > > "seen"
> > > > > > > topic
> > > > > > > > > > > > partitions (post transformation) and before each call
> > to
> > > > > > > > > SinkTask::put
> > > > > > > > > > > > check whether there's any new "unseen" topic
> > partitions,
> > > > and
> > > > > if
> > > > > > > so
> > > > > > > > > call
> > > > > > > > > > > > SinkTask::open (and also update the cache of
> course). I
> > > > don't
> > > > > > > think
> > > > > > > > > > this
> > > > > > > > > > > > would break the existing contract with sink tasks
> where
> > > > > > > > > SinkTask::open
> > > > > > > > > > is
> > > > > > > > > > > > expected to be called for a topic partition before
> any
> > > > > records
> > > > > > > from
> > > > > > > > > the
> > > > > > > > > > > > topic partition are sent via SinkTask::put? The
> > > > > SinkTask::close
> > > > > > > > case
> > > > > > > > > > is a
> > > > > > > > > > > > lot trickier however, and would require some sort of
> > > cache
> > > > > > > eviction
> > > > > > > > > > > policy
> > > > > > > > > > > > that would be deemed appropriate as you pointed out
> > too.
> > > > > > > > > > > >
> > > > > > > > > > > > Thanks,
> > > > > > > > > > > > Yash
> > > > > > > > > > > >
> > > > > > > > > > > > On Mon, Feb 6, 2023 at 11:27 PM Chris Egerton
> > > > > > > > > <chrise@aiven.io.invalid
> > > > > > > > > > >
> > > > > > > > > > > > wrote:
> > > > > > > > > > > >
> > > > > > > > > > > > > Hi Yash,
> > > > > > > > > > > > >
> > > > > > > > > > > > > I've had some time to think on this KIP and I think
> > I'm
> > > > in
> > > > > > > > > agreement
> > > > > > > > > > > > about
> > > > > > > > > > > > > not blocking it on an official compatibility
> library
> > or
> > > > > > adding
> > > > > > > > the
> > > > > > > > > > > "ack"
> > > > > > > > > > > > > API for sink records.
> > > > > > > > > > > > >
> > > > > > > > > > > > > I only have two more thoughts:
> > > > > > > > > > > > >
> > > > > > > > > > > > > 1. Because it is possible to manipulate sink record
> > > > > > partitions
> > > > > > > > and
> > > > > > > > > > > > offsets
> > > > > > > > > > > > > with the current API we provide for
> transformations,
> > I
> > > > > still
> > > > > > > > > believe
> > > > > > > > > > > > > methods should be added to the SinkRecord class to
> > > expose
> > > > > the
> > > > > > > > > > original
> > > > > > > > > > > > > partition and offset, not just the original topic.
> > The
> > > > > > > additional
> > > > > > > > > > > > cognitive
> > > > > > > > > > > > > burden from these two methods is going to be
> minimal
> > > > > anyways;
> > > > > > > > once
> > > > > > > > > > > users
> > > > > > > > > > > > > understand the difference between the transformed
> > topic
> > > > > name
> > > > > > > and
> > > > > > > > > the
> > > > > > > > > > > > > original one, it's going to be trivial for them to
> > > > > understand
> > > > > > > how
> > > > > > > > > > that
> > > > > > > > > > > > same
> > > > > > > > > > > > > difference applies for partitions and offsets. It's
> > not
> > > > > > enough
> > > > > > > to
> > > > > > > > > > scan
> > > > > > > > > > > > the
> > > > > > > > > > > > > set of SMTs provided out of the box with Connect,
> > ones
> > > > > > > developed
> > > > > > > > by
> > > > > > > > > > > > > Confluent, or even everything available on GitHub,
> > > since
> > > > > > there
> > > > > > > > may
> > > > > > > > > be
> > > > > > > > > > > > > closed-source projects out there that rely on this
> > > > ability.
> > > > > > One
> > > > > > > > > > > potential
> > > > > > > > > > > > > use case could be re-routing partitions between
> Kafka
> > > and
> > > > > > some
> > > > > > > > > other
> > > > > > > > > > > > > sharded system.
> > > > > > > > > > > > >
> > > > > > > > > > > > > 2. We still have to address the SinkTask::open [1]
> > and
> > > > > > > > > > SinkTask::close
> > > > > > > > > > > > [2]
> > > > > > > > > > > > > methods. If a connector writes to the external
> system
> > > > using
> > > > > > the
> > > > > > > > > > > > transformed
> > > > > > > > > > > > > topic partitions it reads from Kafka, then it's
> > > possible
> > > > > for
> > > > > > > the
> > > > > > > > > > > > connector
> > > > > > > > > > > > > to lazily instantiate writers for topic partitions
> as
> > > it
> > > > > > > > encounters
> > > > > > > > > > > them
> > > > > > > > > > > > > from records provided in SinkTask::put. However,
> > > > connectors
> > > > > > > also
> > > > > > > > > > need a
> > > > > > > > > > > > way
> > > > > > > > > > > > > to de-allocate those writers (and the resources
> used
> > by
> > > > > them)
> > > > > > > > over
> > > > > > > > > > > time,
> > > > > > > > > > > > > which they can't do as easily. One possible
> approach
> > > here
> > > > > is
> > > > > > to
> > > > > > > > > > > overload
> > > > > > > > > > > > > SinkTask::open and SinkTask::close with variants
> that
> > > > > > > distinguish
> > > > > > > > > > > between
> > > > > > > > > > > > > transformed and original topic partitions, and
> > default
> > > to
> > > > > > > > invoking
> > > > > > > > > > the
> > > > > > > > > > > > > existing methods with just the original topic
> > > partitions.
> > > > > We
> > > > > > > > would
> > > > > > > > > > then
> > > > > > > > > > > > > have several options for how the Connect runtime
> can
> > > > invoke
> > > > > > > these
> > > > > > > > > > > > methods,
> > > > > > > > > > > > > but in general, an approach that guarantees that
> > tasks
> > > > are
> > > > > > > > notified
> > > > > > > > > > of
> > > > > > > > > > > > > transformed topic partitions in SinkTask::open
> before
> > > any
> > > > > > > records
> > > > > > > > > for
> > > > > > > > > > > > that
> > > > > > > > > > > > > partition are given to it in SinkTask::put, and
> > makes a
> > > > > > > > best-effort
> > > > > > > > > > > > attempt
> > > > > > > > > > > > > to close transformed topic partitions that appear
> to
> > no
> > > > > > longer
> > > > > > > be
> > > > > > > > > in
> > > > > > > > > > > use
> > > > > > > > > > > > > based on some eviction policy, would probably be
> > > > > sufficient.
> > > > > > > > > > > > >
> > > > > > > > > > > > > [1] -
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://kafka.apache.org/33/javadoc/org/apache/kafka/connect/sink/SinkTask.html#open(java.util.Collection)
> > > > > > > > > > > > > [2] -
> > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://kafka.apache.org/33/javadoc/org/apache/kafka/connect/sink/SinkTask.html#close(java.util.Collection)
> > > > > > > > > > > > >
> > > > > > > > > > > > > Cheers,
> > > > > > > > > > > > >
> > > > > > > > > > > > > Chris
> > > > > > > > > > > > >
> > > > > > > > > > > > > On Sat, Nov 5, 2022 at 5:46 AM Yash Mayya <
> > > > > > > yash.mayya@gmail.com>
> > > > > > > > > > > wrote:
> > > > > > > > > > > > >
> > > > > > > > > > > > > > Hi Chris,
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Thanks a lot for your inputs!
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > > would provide a simple, clean interface for
> > > > developers
> > > > > to
> > > > > > > > > > determine
> > > > > > > > > > > > > > > which features are supported by the version of
> > the
> > > > > > Connect
> > > > > > > > > > runtime
> > > > > > > > > > > > > > > that their plugin has been deployed onto
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > I do like the idea of having such a public
> > > > compatibility
> > > > > > > > library
> > > > > > > > > -
> > > > > > > > > > I
> > > > > > > > > > > > > think
> > > > > > > > > > > > > > it would remove a lot of restrictions from
> > framework
> > > > > > > > development
> > > > > > > > > if
> > > > > > > > > > > it
> > > > > > > > > > > > > were
> > > > > > > > > > > > > > to be widely adopted.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > > we might consider adding an API to "ack" sink
> > > records
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > I agree that this does seem like a more intuitive
> > and
> > > > > clean
> > > > > > > > API,
> > > > > > > > > > but
> > > > > > > > > > > > I'm
> > > > > > > > > > > > > > concerned about the backward compatibility
> headache
> > > > we'd
> > > > > be
> > > > > > > > > > imposing
> > > > > > > > > > > on
> > > > > > > > > > > > > all
> > > > > > > > > > > > > > existing sink connectors. Connector developers
> will
> > > > have
> > > > > to
> > > > > > > > > > maintain
> > > > > > > > > > > > two
> > > > > > > > > > > > > > separate ways of doing offset management if they
> > want
> > > > to
> > > > > > use
> > > > > > > > the
> > > > > > > > > > new
> > > > > > > > > > > > API
> > > > > > > > > > > > > > but continue supporting older versions of Kafka
> > > > Connect.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > For now, I've reverted the KIP to the previous
> > > > iteration
> > > > > > > which
> > > > > > > > > > > proposed
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > addition of a new `SinkRecord` method to obtain
> the
> > > > > > original
> > > > > > > > > Kafka
> > > > > > > > > > > > topic
> > > > > > > > > > > > > > pre-transformation. One thing to note is that
> I've
> > > > > removed
> > > > > > > the
> > > > > > > > > > method
> > > > > > > > > > > > for
> > > > > > > > > > > > > > obtaining the original Kafka partition after a
> > > cursory
> > > > > > search
> > > > > > > > > > showed
> > > > > > > > > > > > that
> > > > > > > > > > > > > > use cases for partition modifying SMTs are
> > primarily
> > > on
> > > > > the
> > > > > > > > > source
> > > > > > > > > > > > > > connector side.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > Yash
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > On Tue, Nov 1, 2022 at 9:22 PM Chris Egerton
> > > > > > > > > > <chrise@aiven.io.invalid
> > > > > > > > > > > >
> > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Hi all,
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > I have more comments I'd like to make on this
> KIP
> > > > when
> > > > > I
> > > > > > > have
> > > > > > > > > > time
> > > > > > > > > > > > > (sorry
> > > > > > > > > > > > > > > for the delay, Yash, and thanks for your
> > > patience!),
> > > > > but
> > > > > > I
> > > > > > > > did
> > > > > > > > > > want
> > > > > > > > > > > > to
> > > > > > > > > > > > > > > chime in and say that I'm also not sure about
> > > > > overloading
> > > > > > > > > > > > > SinkTask::put.
> > > > > > > > > > > > > > I
> > > > > > > > > > > > > > > share the concerns about creating an intuitive,
> > > > simple
> > > > > > API
> > > > > > > > that
> > > > > > > > > > > Yash
> > > > > > > > > > > > > has
> > > > > > > > > > > > > > > raised. In addition, this approach doesn't seem
> > > very
> > > > > > > > > > > > sustainable--what
> > > > > > > > > > > > > do
> > > > > > > > > > > > > > > we do if we encounter another case in the
> future
> > > that
> > > > > > would
> > > > > > > > > > > warrant a
> > > > > > > > > > > > > > > similar solution? We probably don't want to
> > create
> > > > > three,
> > > > > > > > four,
> > > > > > > > > > > etc.
> > > > > > > > > > > > > > > overloaded variants of the method, each of
> which
> > > > would
> > > > > > have
> > > > > > > > to
> > > > > > > > > be
> > > > > > > > > > > > > > > implemented by connector developers who want to
> > > both
> > > > > > > leverage
> > > > > > > > > the
> > > > > > > > > > > > > latest
> > > > > > > > > > > > > > > and greatest connector APIs and maintain
> > > > compatibility
> > > > > > with
> > > > > > > > > > connect
> > > > > > > > > > > > > > > Clusters running older versions.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > I haven't been able to flesh this out into a
> > design
> > > > > worth
> > > > > > > > > > > publishing
> > > > > > > > > > > > in
> > > > > > > > > > > > > > its
> > > > > > > > > > > > > > > own KIP yet, but one alternative I've pitched
> to
> > a
> > > > few
> > > > > > > people
> > > > > > > > > > with
> > > > > > > > > > > > > > > generally positive interest has been to develop
> > an
> > > > > > official
> > > > > > > > > > > > > compatibility
> > > > > > > > > > > > > > > library for Connect developers. This library
> > would
> > > be
> > > > > > > > released
> > > > > > > > > as
> > > > > > > > > > > its
> > > > > > > > > > > > > own
> > > > > > > > > > > > > > > Maven artifact (separate from connect-api,
> > > > > > connect-runtime,
> > > > > > > > > etc.)
> > > > > > > > > > > and
> > > > > > > > > > > > > > would
> > > > > > > > > > > > > > > provide a simple, clean interface for
> developers
> > to
> > > > > > > determine
> > > > > > > > > > which
> > > > > > > > > > > > > > > features are supported by the version of the
> > > Connect
> > > > > > > runtime
> > > > > > > > > that
> > > > > > > > > > > > their
> > > > > > > > > > > > > > > plugin has been deployed onto. Under the hood,
> > this
> > > > > > library
> > > > > > > > > might
> > > > > > > > > > > use
> > > > > > > > > > > > > > > reflection to determine whether classes,
> methods,
> > > > etc.
> > > > > > are
> > > > > > > > > > > available,
> > > > > > > > > > > > > but
> > > > > > > > > > > > > > > the developer wouldn't have to do anything more
> > > than
> > > > > > check
> > > > > > > > (for
> > > > > > > > > > > > > example)
> > > > > > > > > > > > > > >
> > > `Features.SINK_TASK_ERRANT_RECORD_REPORTER.enabled()`
> > > > > to
> > > > > > > know
> > > > > > > > > at
> > > > > > > > > > > any
> > > > > > > > > > > > > > point
> > > > > > > > > > > > > > > in the lifetime of their connector/task whether
> > > that
> > > > > > > feature
> > > > > > > > is
> > > > > > > > > > > > > provided
> > > > > > > > > > > > > > by
> > > > > > > > > > > > > > > the runtime.
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > One other high-level comment: this doesn't
> > address
> > > > > every
> > > > > > > > case,
> > > > > > > > > > but
> > > > > > > > > > > we
> > > > > > > > > > > > > > might
> > > > > > > > > > > > > > > consider adding an API to "ack" sink records.
> > This
> > > > > could
> > > > > > > use
> > > > > > > > > the
> > > > > > > > > > > > > > > SubmittedRecords class [1] (with some slight
> > > tweaks)
> > > > > > under
> > > > > > > > the
> > > > > > > > > > hood
> > > > > > > > > > > > to
> > > > > > > > > > > > > > > track the latest-acked offset for each topic
> > > > partition.
> > > > > > > This
> > > > > > > > > way,
> > > > > > > > > > > > > > connector
> > > > > > > > > > > > > > > developers won't be responsible for tracking
> > > offsets
> > > > at
> > > > > > all
> > > > > > > > in
> > > > > > > > > > > their
> > > > > > > > > > > > > sink
> > > > > > > > > > > > > > > tasks (eliminating issues with the accuracy of
> > > > > > > > > > post-transformation
> > > > > > > > > > > > > T/P/O
> > > > > > > > > > > > > > > sink record information), and they'll only have
> > to
> > > > > notify
> > > > > > > the
> > > > > > > > > > > Connect
> > > > > > > > > > > > > > > framework when a record has been successfully
> > > > > dispatched
> > > > > > to
> > > > > > > > the
> > > > > > > > > > > > > external
> > > > > > > > > > > > > > > system. This provides a cleaner, friendlier
> API,
> > > and
> > > > > also
> > > > > > > > > enables
> > > > > > > > > > > > more
> > > > > > > > > > > > > > > fine-grained metrics like the ones proposed in
> > > > KIP-767
> > > > > > [2].
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > [1] -
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://github.com/apache/kafka/blob/9ab140d5419d735baae45aff56ffce7f5622744f/connect/runtime/src/main/java/org/apache/kafka/connect/runtime/SubmittedRecords.java
> > > > > > > > > > > > > > > [2] -
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-767%3A+Connect+Latency+Metrics
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Cheers,
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Chris
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > On Tue, Nov 1, 2022 at 11:21 AM Yash Mayya <
> > > > > > > > > yash.mayya@gmail.com
> > > > > > > > > > >
> > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Hi Randall,
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > It's been a while for this one but the more I
> > > think
> > > > > > about
> > > > > > > > it,
> > > > > > > > > > the
> > > > > > > > > > > > > more
> > > > > > > > > > > > > > I
> > > > > > > > > > > > > > > > feel like the current approach with a new
> > > > overloaded
> > > > > > > > > > > > `SinkTask::put`
> > > > > > > > > > > > > > > method
> > > > > > > > > > > > > > > > might not be optimal. We're trying to fix a
> > > pretty
> > > > > > corner
> > > > > > > > > case
> > > > > > > > > > > bug
> > > > > > > > > > > > > here
> > > > > > > > > > > > > > > > (usage of topic mutating SMTs with sink
> > > connectors
> > > > > that
> > > > > > > do
> > > > > > > > > > their
> > > > > > > > > > > > own
> > > > > > > > > > > > > > > offset
> > > > > > > > > > > > > > > > tracking) and I'm not sure that warrants a
> > change
> > > > to
> > > > > > > such a
> > > > > > > > > > > central
> > > > > > > > > > > > > > > > interface method. The new `SinkTask::put`
> > method
> > > > just
> > > > > > > seems
> > > > > > > > > > > > somewhat
> > > > > > > > > > > > > > odd
> > > > > > > > > > > > > > > > and it may not be very understandable for a
> new
> > > > > reader
> > > > > > -
> > > > > > > I
> > > > > > > > > > don't
> > > > > > > > > > > > > think
> > > > > > > > > > > > > > > this
> > > > > > > > > > > > > > > > should be the case for a public interface
> > method.
> > > > > > > > > Furthermore,
> > > > > > > > > > > even
> > > > > > > > > > > > > > with
> > > > > > > > > > > > > > > > elaborate documentation in place, I'm not
> sure
> > if
> > > > > it'll
> > > > > > > be
> > > > > > > > > very
> > > > > > > > > > > > > obvious
> > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > most people what the purpose of having these
> > two
> > > > > `put`
> > > > > > > > > methods
> > > > > > > > > > is
> > > > > > > > > > > > and
> > > > > > > > > > > > > > how
> > > > > > > > > > > > > > > > they should be used by sink task
> > implementations.
> > > > > What
> > > > > > do
> > > > > > > > you
> > > > > > > > > > > > think?
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > Yash
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > On Mon, Oct 10, 2022 at 9:33 PM Yash Mayya <
> > > > > > > > > > yash.mayya@gmail.com
> > > > > > > > > > > >
> > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Hi Randall,
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Thanks a lot for your valuable feedback so
> > far!
> > > > > I've
> > > > > > > > > updated
> > > > > > > > > > > the
> > > > > > > > > > > > > KIP
> > > > > > > > > > > > > > > > based
> > > > > > > > > > > > > > > > > on our discussion above. Could you please
> > take
> > > > > > another
> > > > > > > > > look?
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > > Yash
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > > On Tue, Oct 4, 2022 at 12:40 AM Randall
> > Hauch <
> > > > > > > > > > > rhauch@gmail.com>
> > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >> On Mon, Oct 3, 2022 at 11:45 AM Yash
> Mayya <
> > > > > > > > > > > > yash.mayya@gmail.com>
> > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >> > Hi Randall,
> > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > >> > Thanks for elaborating. I think these
> are
> > > all
> > > > > very
> > > > > > > > good
> > > > > > > > > > > points
> > > > > > > > > > > > > > and I
> > > > > > > > > > > > > > > > see
> > > > > > > > > > > > > > > > >> > why the overloaded `SinkTask::put`
> method
> > > is a
> > > > > > > cleaner
> > > > > > > > > > > > solution
> > > > > > > > > > > > > > > > overall.
> > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > >> > > public void put(Collection<SinkRecord>
> > > > > records,
> > > > > > > > > > > > > Map<SinkRecord,
> > > > > > > > > > > > > > > > >> > TopicPartition> updatedTopicPartitions)
> > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > >> > I think this should be
> > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > >> > `public void put(Collection<SinkRecord>
> > > > records,
> > > > > > > > > > > > Map<SinkRecord,
> > > > > > > > > > > > > > > > >> > TopicPartition>
> originalTopicPartitions)`
> > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > >> > instead because the sink records
> > themselves
> > > > have
> > > > > > the
> > > > > > > > > > updated
> > > > > > > > > > > > > topic
> > > > > > > > > > > > > > > > >> > partitions (i.e. after all
> transformations
> > > > have
> > > > > > been
> > > > > > > > > > > applied)
> > > > > > > > > > > > > and
> > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > >> KIP
> > > > > > > > > > > > > > > > >> > is proposing a way for the tasks to be
> > able
> > > to
> > > > > > > access
> > > > > > > > > the
> > > > > > > > > > > > > original
> > > > > > > > > > > > > > > > topic
> > > > > > > > > > > > > > > > >> > partition (i.e. before transformations
> > have
> > > > been
> > > > > > > > > applied).
> > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >> Sounds good.
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > >> > > Of course, if the developer does not
> > need
> > > > > > separate
> > > > > > > > > > > methods,
> > > > > > > > > > > > > they
> > > > > > > > > > > > > > > can
> > > > > > > > > > > > > > > > >> > easily have the older `put` method
> simply
> > > > > delegate
> > > > > > > to
> > > > > > > > > the
> > > > > > > > > > > > newer
> > > > > > > > > > > > > > > > method.
> > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > >> > If the developer does not need separate
> > > > methods
> > > > > > > (i.e.
> > > > > > > > > they
> > > > > > > > > > > > don't
> > > > > > > > > > > > > > > need
> > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > >> > use this new addition), they can simply
> > > > continue
> > > > > > > > > > > implementing
> > > > > > > > > > > > > just
> > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > >> > older `put` method right?
> > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >> Correct. We should update the JavaDoc of
> > both
> > > > > > methods
> > > > > > > to
> > > > > > > > > > make
> > > > > > > > > > > > this
> > > > > > > > > > > > > > > > clear,
> > > > > > > > > > > > > > > > >> and in general how the two methods should
> > are
> > > > used
> > > > > > and
> > > > > > > > > > should
> > > > > > > > > > > be
> > > > > > > > > > > > > > > > >> implemented. That can be part of the PR,
> and
> > > the
> > > > > KIP
> > > > > > > > > doesn't
> > > > > > > > > > > > need
> > > > > > > > > > > > > > this
> > > > > > > > > > > > > > > > >> wording.
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > >> > > Finally, this gives us a roadmap for
> > > > > > *eventually*
> > > > > > > > > > > > deprecating
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > >> older
> > > > > > > > > > > > > > > > >> > method, once the Connect runtime
> versions
> > > > > without
> > > > > > > this
> > > > > > > > > > > change
> > > > > > > > > > > > > are
> > > > > > > > > > > > > > > old
> > > > > > > > > > > > > > > > >> > enough.
> > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > >> > I'm not sure we'd ever want to deprecate
> > the
> > > > > older
> > > > > > > > > method.
> > > > > > > > > > > > Most
> > > > > > > > > > > > > > > common
> > > > > > > > > > > > > > > > >> sink
> > > > > > > > > > > > > > > > >> > connector implementations do not do
> their
> > > own
> > > > > > offset
> > > > > > > > > > > tracking
> > > > > > > > > > > > > with
> > > > > > > > > > > > > > > > >> > asynchronous processing and will
> probably
> > > > never
> > > > > > > have a
> > > > > > > > > > need
> > > > > > > > > > > > for
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > >> > additional parameter `Map<SinkRecord,
> > > > > > > TopicPartition>
> > > > > > > > > > > > > > > > >> > originalTopicPartitions` in the proposed
> > new
> > > > > `put`
> > > > > > > > > method.
> > > > > > > > > > > > These
> > > > > > > > > > > > > > > > >> connectors
> > > > > > > > > > > > > > > > >> > can continue implementing only the
> > existing
> > > > > > > > > > `SinkTask::put`
> > > > > > > > > > > > > method
> > > > > > > > > > > > > > > > which
> > > > > > > > > > > > > > > > >> > will be called by the default
> > implementation
> > > > of
> > > > > > the
> > > > > > > > > newer
> > > > > > > > > > > > > > overloaded
> > > > > > > > > > > > > > > > >> `put`
> > > > > > > > > > > > > > > > >> > method.
> > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >> +1
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > >> > > the pre-commit methods use the same
> > > > > > > > > `Map<TopicPartition,
> > > > > > > > > > > > > > > > >> > OffsetAndMetadata> currentOffsets` data
> > > > > structure
> > > > > > > I'm
> > > > > > > > > > > > suggesting
> > > > > > > > > > > > > > be
> > > > > > > > > > > > > > > > >> used.
> > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > >> > The data structure you're suggesting be
> > used
> > > > is
> > > > > a
> > > > > > > > > > > > > `Map<SinkRecord,
> > > > > > > > > > > > > > > > >> > TopicPartition>` which will map
> > `SinkRecord`
> > > > > > objects
> > > > > > > > to
> > > > > > > > > > the
> > > > > > > > > > > > > > original
> > > > > > > > > > > > > > > > >> topic
> > > > > > > > > > > > > > > > >> > partition of the corresponding
> > > > `ConsumerRecord`
> > > > > > > right?
> > > > > > > > > To
> > > > > > > > > > > > > clarify,
> > > > > > > > > > > > > > > > this
> > > > > > > > > > > > > > > > >> is
> > > > > > > > > > > > > > > > >> > a new data structure that will need to
> be
> > > > > managed
> > > > > > in
> > > > > > > > the
> > > > > > > > > > > > > > > > >> `WorkerSinkTask`.
> > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >> Ah, you're right. Thanks for the
> correction.
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >> Best regards,
> > > > > > > > > > > > > > > > >> Randall
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >> > Thanks,
> > > > > > > > > > > > > > > > >> > Yash
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >> > On Mon, Oct 3, 2022 at 1:20 AM Randall
> > > Hauch <
> > > > > > > > > > > > rhauch@gmail.com>
> > > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > >> > > Hi, Yash.
> > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > >> > > I'm not sure I quite understand why it
> > > would
> > > > > be
> > > > > > > > > "easier"
> > > > > > > > > > > for
> > > > > > > > > > > > > > > > connector
> > > > > > > > > > > > > > > > >> > > > developers to account for
> implementing
> > > two
> > > > > > > > different
> > > > > > > > > > > > > > overloaded
> > > > > > > > > > > > > > > > >> `put`
> > > > > > > > > > > > > > > > >> > > > methods (assuming that they want to
> > use
> > > > this
> > > > > > new
> > > > > > > > > > > feature)
> > > > > > > > > > > > > > versus
> > > > > > > > > > > > > > > > >> using
> > > > > > > > > > > > > > > > >> > a
> > > > > > > > > > > > > > > > >> > > > try-catch block around `SinkRecord`
> > > access
> > > > > > > > methods?
> > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > >> > > Using a try-catch to try around an API
> > > > method
> > > > > > that
> > > > > > > > > > *might*
> > > > > > > > > > > > be
> > > > > > > > > > > > > > > there
> > > > > > > > > > > > > > > > >> is a
> > > > > > > > > > > > > > > > >> > > very unusual thing for most
> developers.
> > > > > > > > Unfortunately,
> > > > > > > > > > > we've
> > > > > > > > > > > > > had
> > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > >> > resort
> > > > > > > > > > > > > > > > >> > > to this atypical approach with Connect
> > in
> > > > > places
> > > > > > > > when
> > > > > > > > > > > there
> > > > > > > > > > > > > was
> > > > > > > > > > > > > > no
> > > > > > > > > > > > > > > > >> good
> > > > > > > > > > > > > > > > >> > > alternative. We seem to relying upon
> > > pattern
> > > > > > > because
> > > > > > > > > > it's
> > > > > > > > > > > > > easier
> > > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > >> us,
> > > > > > > > > > > > > > > > >> > > not because it offers a better
> > experience
> > > > for
> > > > > > > > > Connector
> > > > > > > > > > > > > > > developers.
> > > > > > > > > > > > > > > > >> IMO,
> > > > > > > > > > > > > > > > >> > if
> > > > > > > > > > > > > > > > >> > > there's a practical alternative that
> > uses
> > > > > normal
> > > > > > > > > > > development
> > > > > > > > > > > > > > > > practices
> > > > > > > > > > > > > > > > >> > and
> > > > > > > > > > > > > > > > >> > > techniques, then we should use that
> > > > > alternative.
> > > > > > > > IIUC,
> > > > > > > > > > > there
> > > > > > > > > > > > > is
> > > > > > > > > > > > > > at
> > > > > > > > > > > > > > > > >> least
> > > > > > > > > > > > > > > > >> > > one practical alternative for this KIP
> > > that
> > > > > > would
> > > > > > > > not
> > > > > > > > > > > > require
> > > > > > > > > > > > > > > > >> developers
> > > > > > > > > > > > > > > > >> > to
> > > > > > > > > > > > > > > > >> > > use the unusual try-catch to handle
> the
> > > case
> > > > > > where
> > > > > > > > > > methods
> > > > > > > > > > > > are
> > > > > > > > > > > > > > not
> > > > > > > > > > > > > > > > >> found.
> > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > >> > > I also think having two `put` methods
> is
> > > > > easier
> > > > > > > when
> > > > > > > > > the
> > > > > > > > > > > > > > Connector
> > > > > > > > > > > > > > > > >> has to
> > > > > > > > > > > > > > > > >> > > do different things for different
> > Connect
> > > > > > > runtimes,
> > > > > > > > > too.
> > > > > > > > > > > One
> > > > > > > > > > > > > of
> > > > > > > > > > > > > > > > those
> > > > > > > > > > > > > > > > >> > > methods is called by newer Connect
> > > runtimes
> > > > > with
> > > > > > > the
> > > > > > > > > new
> > > > > > > > > > > > > > behavior,
> > > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > >> > the
> > > > > > > > > > > > > > > > >> > > other method is called by an older
> > Connect
> > > > > > > runtime.
> > > > > > > > Of
> > > > > > > > > > > > course,
> > > > > > > > > > > > > > if
> > > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > >> > > developer does not need separate
> > methods,
> > > > they
> > > > > > can
> > > > > > > > > > easily
> > > > > > > > > > > > have
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > >> older
> > > > > > > > > > > > > > > > >> > > `put` method simply delegate to the
> > newer
> > > > > > method.
> > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > >> > > Finally, this gives us a roadmap for
> > > > > > *eventually*
> > > > > > > > > > > > deprecating
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > >> older
> > > > > > > > > > > > > > > > >> > > method, once the Connect runtime
> > versions
> > > > > > without
> > > > > > > > this
> > > > > > > > > > > > change
> > > > > > > > > > > > > > are
> > > > > > > > > > > > > > > > old
> > > > > > > > > > > > > > > > >> > > enough.
> > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > >> > > I think the advantage of going with
> the
> > > > > > > > > > > > > > > > >> > > > proposed approach in the KIP is that
> > it
> > > > > > wouldn't
> > > > > > > > > > require
> > > > > > > > > > > > > extra
> > > > > > > > > > > > > > > > >> > > book-keeping
> > > > > > > > > > > > > > > > >> > > > (the Map<SinkRecord,
> > > > > > > > > > > > > > > > >> > > > TopicPartition> in `WorkerSinkTask`
> in
> > > > your
> > > > > > > > proposed
> > > > > > > > > > > > > approach)
> > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > >> > > The connector does have to do some of
> > this
> > > > > > > > bookkeeping
> > > > > > > > > > in
> > > > > > > > > > > > how
> > > > > > > > > > > > > > they
> > > > > > > > > > > > > > > > >> track
> > > > > > > > > > > > > > > > >> > > the topic partition offsets used in
> the
> > > > > > > `preCommit`,
> > > > > > > > > and
> > > > > > > > > > > the
> > > > > > > > > > > > > > > > >> pre-commit
> > > > > > > > > > > > > > > > >> > > methods use the same
> > `Map<TopicPartition,
> > > > > > > > > > > OffsetAndMetadata>
> > > > > > > > > > > > > > > > >> > > currentOffsets`
> > > > > > > > > > > > > > > > >> > > data structure I'm suggesting be used.
> > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > >> > > I hope that helps.
> > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > >> > > Best regards,
> > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > >> > > Randall
> > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > >> > > On Mon, Sep 26, 2022 at 9:38 AM Yash
> > > Mayya <
> > > > > > > > > > > > > > yash.mayya@gmail.com>
> > > > > > > > > > > > > > > > >> wrote:
> > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > >> > > > Hi Randall,
> > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > >> > > > Thanks for reviewing the KIP!
> > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > >> > > > > That latter logic can get quite
> > ugly.
> > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > >> > > > I'm not sure I quite understand why
> it
> > > > would
> > > > > > be
> > > > > > > > > > "easier"
> > > > > > > > > > > > for
> > > > > > > > > > > > > > > > >> connector
> > > > > > > > > > > > > > > > >> > > > developers to account for
> implementing
> > > two
> > > > > > > > different
> > > > > > > > > > > > > > overloaded
> > > > > > > > > > > > > > > > >> `put`
> > > > > > > > > > > > > > > > >> > > > methods (assuming that they want to
> > use
> > > > this
> > > > > > new
> > > > > > > > > > > feature)
> > > > > > > > > > > > > > versus
> > > > > > > > > > > > > > > > >> using
> > > > > > > > > > > > > > > > >> > a
> > > > > > > > > > > > > > > > >> > > > try-catch block around `SinkRecord`
> > > access
> > > > > > > > methods?
> > > > > > > > > In
> > > > > > > > > > > > both
> > > > > > > > > > > > > > > > cases, a
> > > > > > > > > > > > > > > > >> > > > connector developer would need to
> > write
> > > > > > > additional
> > > > > > > > > > code
> > > > > > > > > > > in
> > > > > > > > > > > > > > order
> > > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > > >> > > ensure
> > > > > > > > > > > > > > > > >> > > > that their connector continues
> working
> > > > with
> > > > > > > older
> > > > > > > > > > > Connect
> > > > > > > > > > > > > > > > runtimes.
> > > > > > > > > > > > > > > > >> > > > Furthermore, we would probably need
> to
> > > > > > carefully
> > > > > > > > > > > document
> > > > > > > > > > > > > how
> > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > > >> > > > implementation for the older `put`
> > > method
> > > > > > should
> > > > > > > > > look
> > > > > > > > > > > like
> > > > > > > > > > > > > for
> > > > > > > > > > > > > > > > >> > connectors
> > > > > > > > > > > > > > > > >> > > > that want to use this new feature. I
> > > think
> > > > > the
> > > > > > > > > > advantage
> > > > > > > > > > > > of
> > > > > > > > > > > > > > > going
> > > > > > > > > > > > > > > > >> with
> > > > > > > > > > > > > > > > >> > > the
> > > > > > > > > > > > > > > > >> > > > proposed approach in the KIP is that
> > it
> > > > > > wouldn't
> > > > > > > > > > require
> > > > > > > > > > > > > extra
> > > > > > > > > > > > > > > > >> > > book-keeping
> > > > > > > > > > > > > > > > >> > > > (the Map<SinkRecord,
> > > > > > > > > > > > > > > > >> > > > TopicPartition> in `WorkerSinkTask`
> in
> > > > your
> > > > > > > > proposed
> > > > > > > > > > > > > approach)
> > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > >> also
> > > > > > > > > > > > > > > > >> > > the
> > > > > > > > > > > > > > > > >> > > > fact that the try-catch based logic
> is
> > > an
> > > > > > > already
> > > > > > > > > > > > > established
> > > > > > > > > > > > > > > > >> pattern
> > > > > > > > > > > > > > > > >> > > > through
> > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-610%3A+Error+Reporting+in+Sink+Connectors
> > > > > > > > > > > > > > > > >> > > > and other KIPs which added methods
> to
> > > > > > > source/sink
> > > > > > > > > > > > > > connector/task
> > > > > > > > > > > > > > > > >> > > contexts.
> > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > >> > > > Let me know if you still feel that
> > > having
> > > > a
> > > > > > new
> > > > > > > > > > > overloaded
> > > > > > > > > > > > > put
> > > > > > > > > > > > > > > > >> method
> > > > > > > > > > > > > > > > >> > is
> > > > > > > > > > > > > > > > >> > > a
> > > > > > > > > > > > > > > > >> > > > cleaner solution and I'd be happy to
> > > > > > reconsider!
> > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > >> > > > Thanks,
> > > > > > > > > > > > > > > > >> > > > Yash
> > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > >> > > > On Thu, Sep 22, 2022 at 11:18 PM
> > Randall
> > > > > > Hauch <
> > > > > > > > > > > > > > > rhauch@gmail.com>
> > > > > > > > > > > > > > > > >> > wrote:
> > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > >> > > > > Hi, Yash. Thanks for picking up
> this
> > > KIP
> > > > > and
> > > > > > > > > > > discussion.
> > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > >> > > > > The KIP includes this rejected
> > > > > alternative:
> > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > >> > > > > > 4. Update SinkTask.put in any
> way
> > to
> > > > > pass
> > > > > > > the
> > > > > > > > > new
> > > > > > > > > > > > > > > information
> > > > > > > > > > > > > > > > >> > outside
> > > > > > > > > > > > > > > > >> > > > > > SinkRecord (e.g. a Map or a
> > derived
> > > > > class)
> > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > >> > > > > >    -
> > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > >> > > > > >    Much more disruptive change
> > > without
> > > > > > > > > > considerable
> > > > > > > > > > > > pros
> > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > >> > > > > One advantage about doing this is
> > that
> > > > > sink
> > > > > > > > > > connector
> > > > > > > > > > > > > > > > >> implementations
> > > > > > > > > > > > > > > > >> > > can
> > > > > > > > > > > > > > > > >> > > > > more easily implement two
> different
> > > > > > "put(...)"
> > > > > > > > > > methods
> > > > > > > > > > > > to
> > > > > > > > > > > > > > > handle
> > > > > > > > > > > > > > > > >> > > running
> > > > > > > > > > > > > > > > >> > > > in
> > > > > > > > > > > > > > > > >> > > > > a variety of runtimes, without
> > having
> > > to
> > > > > use
> > > > > > > > > > try-catch
> > > > > > > > > > > > > logic
> > > > > > > > > > > > > > > > >> around
> > > > > > > > > > > > > > > > >> > the
> > > > > > > > > > > > > > > > >> > > > > newer SinkRecord access methods.
> > That
> > > > > latter
> > > > > > > > logic
> > > > > > > > > > can
> > > > > > > > > > > > get
> > > > > > > > > > > > > > > quite
> > > > > > > > > > > > > > > > >> > ugly.
> > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > >> > > > > For example, the existing `put`
> > method
> > > > has
> > > > > > > this
> > > > > > > > > > > > signature:
> > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > >> > > > > public abstract void
> > > > > > > put(Collection<SinkRecord>
> > > > > > > > > > > > records);
> > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > >> > > > > If we added an overloaded method
> > that
> > > > > passed
> > > > > > > in
> > > > > > > > a
> > > > > > > > > > map
> > > > > > > > > > > of
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > old
> > > > > > > > > > > > > > > > >> > > > > topic+partition for each record
> (and
> > > > > defined
> > > > > > > the
> > > > > > > > > > > absence
> > > > > > > > > > > > > of
> > > > > > > > > > > > > > an
> > > > > > > > > > > > > > > > >> entry
> > > > > > > > > > > > > > > > >> > as
> > > > > > > > > > > > > > > > >> > > > > having an unchanged topic and
> > > > partition):
> > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > >> > > > > public void
> > put(Collection<SinkRecord>
> > > > > > > records,
> > > > > > > > > > > > > > > Map<SinkRecord,
> > > > > > > > > > > > > > > > >> > > > > TopicPartition>
> > > updatedTopicPartitions)
> > > > {
> > > > > > > > > > > > > > > > >> > > > > put(records);
> > > > > > > > > > > > > > > > >> > > > > }
> > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > >> > > > > then a `SinkTask` implementation
> > that
> > > > > wants
> > > > > > to
> > > > > > > > use
> > > > > > > > > > > this
> > > > > > > > > > > > > new
> > > > > > > > > > > > > > > > >> feature
> > > > > > > > > > > > > > > > >> > > could
> > > > > > > > > > > > > > > > >> > > > > simply implement both methods:
> > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > >> > > > > public void
> > put(Collection<SinkRecord>
> > > > > > > records)
> > > > > > > > {
> > > > > > > > > > > > > > > > >> > > > > // Running in an older runtime, so
> > no
> > > > > > tracking
> > > > > > > > of
> > > > > > > > > > > > > > SMT-modified
> > > > > > > > > > > > > > > > >> topic
> > > > > > > > > > > > > > > > >> > > > names
> > > > > > > > > > > > > > > > >> > > > > or partitions
> > > > > > > > > > > > > > > > >> > > > > put(records, Map.of());
> > > > > > > > > > > > > > > > >> > > > > }
> > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > >> > > > > public void
> > put(Collection<SinkRecord>
> > > > > > > records,
> > > > > > > > > > > > > > > Map<SinkRecord,
> > > > > > > > > > > > > > > > >> > > > > TopicPartition>
> > > updatedTopicPartitions)
> > > > {
> > > > > > > > > > > > > > > > >> > > > > // real logic here
> > > > > > > > > > > > > > > > >> > > > > }
> > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > >> > > > > This seems a lot easier than
> having
> > to
> > > > use
> > > > > > > > > try-catch
> > > > > > > > > > > > > logic,
> > > > > > > > > > > > > > > yet
> > > > > > > > > > > > > > > > >> still
> > > > > > > > > > > > > > > > >> > > > > allows sink connectors to utilize
> > the
> > > > new
> > > > > > > > > > > functionality
> > > > > > > > > > > > > and
> > > > > > > > > > > > > > > > still
> > > > > > > > > > > > > > > > >> > work
> > > > > > > > > > > > > > > > >> > > > with
> > > > > > > > > > > > > > > > >> > > > > older Connect runtimes.
> > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > >> > > > > WDYT?
> > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > >> > > > > Randall
> > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > >> > > > > On Thu, Sep 8, 2022 at 7:03 AM
> Yash
> > > > Mayya
> > > > > <
> > > > > > > > > > > > > > > yash.mayya@gmail.com
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > >> > > wrote:
> > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > >> > > > > > Hi all,
> > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > >> > > > > > I would like to (re)start a new
> > > > > discussion
> > > > > > > > > thread
> > > > > > > > > > on
> > > > > > > > > > > > > > KIP-793
> > > > > > > > > > > > > > > > >> (Kafka
> > > > > > > > > > > > > > > > >> > > > > > Connect) which proposes some
> > > additions
> > > > > to
> > > > > > > the
> > > > > > > > > > public
> > > > > > > > > > > > > > > > SinkRecord
> > > > > > > > > > > > > > > > >> > > > interface
> > > > > > > > > > > > > > > > >> > > > > > in order to support topic
> mutating
> > > > SMTs
> > > > > > for
> > > > > > > > sink
> > > > > > > > > > > > > > connectors
> > > > > > > > > > > > > > > > >> that do
> > > > > > > > > > > > > > > > >> > > > their
> > > > > > > > > > > > > > > > >> > > > > > own offset tracking.
> > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > >> > > > > > Links:
> > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > >> > > > > > KIP:
> > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=191336830
> > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > >> > > > > > Older discussion thread:
> > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > >
> > > > > > https://lists.apache.org/thread/00kcth6057jdcsyzgy1x8nb2s1cymy8h
> > > > > > > ,
> > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > >
> > > > > > https://lists.apache.org/thread/rzqkm0q5y5v3vdjhg8wqppxbkw7nyopj
> > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > >> > > > > > Jira:
> > > > > > > > > > > > https://issues.apache.org/jira/browse/KAFKA-13431
> > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > >> > > > > > Thanks,
> > > > > > > > > > > > > > > > >> > > > > > Yash
> > > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
>

Re: [DISCUSS] KIP-793: Sink Connectors: Support topic-mutating SMTs for async connectors (preCommit users)

[Yash Mayya <ya...@gmail.com>]

Hi Greg,

Thanks for the detailed review!

> What is the expected state/behavior for SinkRecords
> which do not have original T/P/O information after the
> upgrade? Just browsing, it appears that tests make
> extensive use of the existing public SinkRecord
> constructors  for both Transformations and Connectors.

I'm not sure I follow - are you asking about how the tests will be updated
post this change or about how upgrades will look like for clusters in
production? For the latter, we won't have to worry about sink records
without original T/P/O information at all once a cluster is fully rolled
and we will make it (hopefully) abundantly clear that connectors need to
account for missing original T/P/O getter methods if they expect to be
deployed on older Connect runtimes.

> What is the expected behavior for Transformation
> implementations which do not use the newRecord
> methods and instead use public SinkRecord constructors?
> The KIP mentions this as a justification for the
> originalKafkaOffset method, but if existing implementations
> are using the existing constructors, those constructors won't
> forward the original T/P/O information to later transforms or
> the task.

There shouldn't be any difference in behavior here - the framework will add
the original T/P/O metadata to the record after the entire transformation
chain has been applied and just before sending the record to the task for
processing. The KIP doesn't propose that transformations themselves should
also be able to retrieve original T/P/O information for a sink record.

> This reasoning and the KIP design seems to imply that the
> connector is better equipped to solve this problem than the
> framework, but the stated reasons are not convincing for me.

This was added to the KIP by the original author, but I don't think the
intention was to imply that the connector is better equipped to solve this
problem than the framework. The intention is to provide complete
information to the connector ("physical" and "virtual coordinates" instead
of the currently incomplete "virtual coordinates" as you've termed it) so
that connectors can use the virtual coordinates for writing data to the
sink system and physical coordinates for offset reporting back to the
framework. The rejected alternative basically says that we can't do a
deterministic mapping from virtual coordinates to physical coordinates
without doing a lot of book-keeping.

I agree with the rest of your analysis on the tradeoffs between the
proposed approach versus the seemingly more attractive approach of handling
everything purely in the framework and only exposing "virtual coordinates"
to the connectors. I think the biggest thorn here is maintaining backward
compatibility with the considerable ecosystem of existing connectors which
is something Connect has always been burdened by.

Thanks,
Yash

On Wed, Mar 8, 2023 at 6:54 AM Greg Harris <gr...@aiven.io.invalid>
wrote:

> Hi Yash,
>
> I always use this issue as an example of a bug being caused by design
> rather than by implementation error, and once it's fixed I'll need to find
> something else to talk about :)
> So glad to see this get fixed!
>
> I'll chime in to support some of the earlier discussions that seem to have
> been resolved:
>
> 1. With respect to SinkRecord methods vs an overloaded put(): I agree with
> the current design but I justify it a little bit differently than has
> already been discussed.
> If we were designing this interface on day 1 without backwards
> compatibility in mind, which design would make more sense? Or for a
> different framing: In the future when old runtimes and connectors are
> retired and the old interfaces are removed, which design is going to look
> more strange and unmotivated?
> Applied to this design decision, I would say that the original T/P/O are
> properties of a single SinkRecord and make sense as getters, and it would
> be strange to store them in an auxiliary map.
>
> 2. Following up this change with a compatibility library to make the
> interface easier to use is the right choice to make here. This change
> should be focused on correctness in allowing developers to fix the
> incompatibility and we can be concerned with coming up with a more
> ergonomic solution in the compatibility library.
> The API should be focused on generality, correctness, and performance
> because those cannot be worked-around after the fact. Connector
> implementations and/or libraries can be concerned with trading off some
> generality and/or performance for ease-of-use.
>
> 3. I think that the difference in behavior of the new open/close methods as
> compared to the old methods is significant, and requires good documentation
> to help connector developers avoid lazy and incorrect migrations. I am
> happy to have that addressed in code review after the KIP is approved.
>
> I had some questions:
>
> 4. What is the expected state/behavior for SinkRecords which do not have
> original T/P/O information after the upgrade? Just browsing, it appears
> that tests make extensive use of the existing public SinkRecord
> constructors for both Transformations and Connectors.
>
> 5. What is the expected behavior for Transformation implementations which
> do not use the newRecord methods and instead use public SinkRecord
> constructors? The KIP mentions this as a justification for the
> originalKafkaOffset method, but if existing implementations are using the
> existing constructors, those constructors won't forward the original T/P/O
> information to later transforms or the task.
>
> For the last few points, I want to discuss this rejected alternative:
>
> > Address the offsets problem entirely within the framework, doing some
> kind of mapping from the transformed topic back to the original topic.
> > * This would only work in the cases where there’s no overlap between the
> transformed topic names, but would break for the rest of the
> transformations (e.g. static transformation, topic = “a”).
> > * Even if we wanted to limit the support to those cases, it would require
> considerable bookkeeping to add a validation to verify that the
> transformation chain adheres to that expectation (and fail fast if it
> doesn’t).
>
> 6. This reasoning and the KIP design seems to imply that the connector is
> better equipped to solve this problem than the framework, but the stated
> reasons are not convincing for me.
> * A static transformation still causes an offset collision in the connector
> * The connector is not permitted to see the transformation chain to do any
> fail-fast assertions
>
> Suppose we were to think of the records at the end of the transformation
> chain as being in "virtual partitions" with "virtual offsets".
> For example, with identity-routing SMTs, the virtual coordinates are
> exactly the same as the underlying physical coordinates. For 1-1 renames,
> each virtual topic would be the renamed topic corresponding to the
> underlying topic. For fan-out from one topic to multiple virtual topics,
> virtual offsets would use the underlying kafka offsets with gaps for
> records going to other virtual partitions. Virtual topics with dropped
> records have similar gaps in the offsets.
> Currently, these virtual coordinates are passed into the connector via
> SinkTask::put, but SinkTask::open/close/preCommit and
> SinkTaskContext::assignment/offsets/pause/resume all use physical
> coordinates.
> This proposal patches put,open, and close to have both physical and virtual
> coordinates, but leaves the other methods with physical coordinates. After
> this proposal, connectors would be intentionally made aware of the
> distinction between physical and virtual coordinates, and manage their own
> bookkeeping for the two systems.
>
> To avoid that connector logic, we could use virtual coordinates in all
> connector calls, never revealing that they are different from the physical
> coordinates. There's a whole design shopping list that we'd need:
> * Renumbering mechanism for disambiguating and making virtual offsets
> monotonic in the case of topic/partition collisions
> * Data structure and strategy for translating virtual offsets back to
> physical offsets
> * New limits on SinkTaskContext::offsets() calls to prevent rewinding
> before the latest commit
> * Backwards compatibility and upgrade design
>
> 7. This alternative was very appealing to me, because the strength of a
> plugin framework is the composability of different components. Among a
> collection of N connectors and M transforms, it should ideally only take
> N + M work to understand how the components combine to build the whole.
> However, once you start adding special cases to some plugins to support
> interactions with others, the whole system can take N * M work to
> understand. From a complexity standpoint, it would be very good for the
> framework to solve this in a way which was connector-agnostic.
> The current design compromises the logical isolation of the plugins
> slightly, but they can collapse offsets very memory-efficiently, and re-use
> the existing raw coordinate functions and keep everything else backwards
> compatible. After deriving all of the above, I think that's a reasonable
> tradeoff to make.
>
> Thanks,
> Greg
>
> On Tue, Feb 21, 2023 at 10:17 AM Chris Egerton <ch...@aiven.io.invalid>
> wrote:
>
> > Hi Yash,
> >
> > We'll probably want to make a few tweaks to the Javadocs for the new
> > methods (I'm imagining that notes on compatibility with older versions
> will
> > be required), but I believe what's proposed in the KIP is good enough to
> > approve with the understanding that it may not exactly match what gets
> > implemented/merged.
> >
> > LGTM, thanks again for the KIP!
> >
> > Cheers,
> >
> > Chris
> >
> > On Tue, Feb 21, 2023 at 12:18 PM Yash Mayya <ya...@gmail.com>
> wrote:
> >
> > > Hi Chris,
> > >
> > > > we might try to introduce a framework-level configuration
> > > > property to dictate which of the pre-transform and post-transform
> > > > topic partitions are used for the fallback call to the single-arg
> > > > variant if a task class has not overridden the multi-arg variant
> > >
> > > Thanks for the explanation and I agree that this will be a tad bit too
> > > convoluted. :)
> > >
> > > Please do let me know if you'd like any further amendments to the KIP!
> > >
> > > Thanks,
> > > Yash
> > >
> > > On Tue, Feb 21, 2023 at 8:42 PM Chris Egerton <chrise@aiven.io.invalid
> >
> > > wrote:
> > >
> > > > Hi Yash,
> > > >
> > > > I think the use case for pre-transform TPO coordinates (and topic
> > > partition
> > > > writers created/destroyed in close/open) tends to boil down to
> > > exactly-once
> > > > semantics, where it's desirable to preserve the guarantees that Kafka
> > > > provides (every record has a unique TPO trio, and records are ordered
> > by
> > > > offset within a topic partition).
> > > >
> > > > It's my understanding that this approach is utilized in several
> > > connectors
> > > > out there today, and it might break these connectors to start using
> the
> > > > post-transform topic partitions automatically in their open/close
> > > methods.
> > > >
> > > > If we want to get really fancy with this and try to obviate or at
> least
> > > > reduce the need for per-connector code changes, we might try to
> > > introduce a
> > > > framework-level configuration property to dictate which of the
> > > > pre-transform and post-transform topic partitions are used for the
> > > fallback
> > > > call to the single-arg variant if a task class has not overridden the
> > > > multi-arg variant. But I think this is going a bit too far and would
> > > prefer
> > > > to keep things simple(r) for now.
> > > >
> > > > Cheers,
> > > >
> > > > Chris
> > > >
> > > >
> > > > On Sun, Feb 19, 2023 at 2:34 AM Yash Mayya <ya...@gmail.com>
> > wrote:
> > > >
> > > > > Hi Chris,
> > > > >
> > > > > > I was actually envisioning something like `void
> > > > > > open(Collection<TopicPartition> originalPartitions,
> > > > > > Collection<TopicPartition> transformedPartitions)`
> > > > >
> > > > > Ah okay, this does make a lot more sense. Sorry, I think I
> > > misunderstood
> > > > > you earlier. I do agree with you that this seems better than
> > splitting
> > > it
> > > > > off into two new sets of open / close methods from a complexity
> > > > standpoint.
> > > > >
> > > > > > Plus, if a connector is intentionally designed to use
> > > > > > pre-transformation topic partitions in its open/close
> > > > > > methods, wouldn't we just be trading one form of the
> > > > > >  problem for another by making this switch?
> > > > >
> > > > > On thinking about this a bit more, I'm not so convinced that we
> need
> > to
> > > > > expose the pre-transform / original topic partitions in the new
> open
> > /
> > > > > close methods. The purpose of the open / close methods is to allow
> > sink
> > > > > tasks to allocate and deallocate resources for each topic partition
> > > > > assigned to the task and the purpose of topic-mutating SMTs is to
> > > > > essentially modify the source topic name from the point of view of
> > the
> > > > sink
> > > > > connector. Why would a sink connector ever need to or want to
> > allocate
> > > > > resources for pre-transform topic partitions? Is the argument here
> > that
> > > > > since we'll be exposing both the pre-transform and post-transform
> > topic
> > > > > partitions per record, we should also expose the same info via
> open /
> > > > close
> > > > > and allow sink connector implementations to disregard
> topic-mutating
> > > SMTs
> > > > > completely if they wanted to?
> > > > >
> > > > > Either way, I've gone ahead and updated the KIP to reflect all of
> > > > > our previous discussion here since it had become quite outdated.
> I've
> > > > also
> > > > > updated the KIP title from "Sink Connectors: Support topic-mutating
> > > SMTs
> > > > > for async connectors (preCommit users)" to "Allow sink connectors
> to
> > be
> > > > > used with topic-mutating SMTs" since the improvements to the open /
> > > close
> > > > > mechanism doesn't pertain only to asynchronous sink connectors. The
> > new
> > > > KIP
> > > > > URL is:
> > > > >
> > > > >
> > > >
> > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-793%3A+Allow+sink+connectors+to+be+used+with+topic-mutating+SMTs
> > > > >
> > > > >
> > > > > Thanks,
> > > > > Yash
> > > > >
> > > > > On Tue, Feb 14, 2023 at 11:39 PM Chris Egerton
> > <chrise@aiven.io.invalid
> > > >
> > > > > wrote:
> > > > >
> > > > > > Hi Yash,
> > > > > >
> > > > > > I was actually envisioning something like `void
> > > > > > open(Collection<TopicPartition>
> > > > > > originalPartitions, Collection<TopicPartition>
> > > transformedPartitions)`,
> > > > > > since we already convert and transform each batch of records that
> > we
> > > > poll
> > > > > > from the sink task's consumer en masse, meaning we could discover
> > > > several
> > > > > > new transformed partitions in between consecutive calls to
> > > > SinkTask::put.
> > > > > >
> > > > > > It's also worth noting that we'll probably want to deprecate the
> > > > existing
> > > > > > open/close methods, at which point keeping one non-deprecated
> > variant
> > > > of
> > > > > > each seems more appealing and less complex than keeping two.
> > > > > >
> > > > > > Honestly though, I think we're both on the same page enough that
> I
> > > > > wouldn't
> > > > > > object to either approach. We've probably reached the saturation
> > > point
> > > > > for
> > > > > > ROI here and as long as we provide developers a way to get the
> > > > > information
> > > > > > they need from the runtime and take care to add Javadocs and
> update
> > > our
> > > > > > docs page (possibly including the connector development
> > quickstart),
> > > it
> > > > > > should be fine.
> > > > > >
> > > > > > At this point, it might be worth updating the KIP based on recent
> > > > > > discussion so that others can see the latest proposal, and we can
> > > both
> > > > > take
> > > > > > a look and make sure everything looks good enough before opening
> a
> > > vote
> > > > > > thread.
> > > > > >
> > > > > > Finally, I think you make a convincing case for a time-based
> > eviction
> > > > > > policy. I wasn't thinking about the fairly common SMT pattern of
> > > > > deriving a
> > > > > > topic name from, e.g., a record field or header.
> > > > > >
> > > > > > Cheers,
> > > > > >
> > > > > > Chris
> > > > > >
> > > > > > On Tue, Feb 14, 2023 at 11:42 AM Yash Mayya <
> yash.mayya@gmail.com>
> > > > > wrote:
> > > > > >
> > > > > > > Hi Chris,
> > > > > > >
> > > > > > > > Plus, if a connector is intentionally designed to
> > > > > > > > use pre-transformation topic partitions in its
> > > > > > > > open/close methods, wouldn't we just be trading
> > > > > > > > one form of the problem for another by making this
> > > > > > > > switch?
> > > > > > >
> > > > > > > Thanks, this makes sense, and given that the KIP already
> > proposes a
> > > > way
> > > > > > for
> > > > > > > sink connector implementations to distinguish between
> > pre-transform
> > > > and
> > > > > > > post-transform topics per record, I think I'm convinced that
> > going
> > > > with
> > > > > > new
> > > > > > > `open()` / `close()` methods is the right approach. However, I
> > > still
> > > > > feel
> > > > > > > like having overloaded methods will make it a lot less
> > unintuitive
> > > > > given
> > > > > > > that the two sets of methods would be different in terms of
> when
> > > > > they're
> > > > > > > called and what arguments they are passed (also I'm presuming
> > that
> > > > the
> > > > > > > overloaded methods you're prescribing will only have a single
> > > > > > > `TopicPartition` rather than a `Collection<TopicPartition>` as
> > > their
> > > > > > > parameters). I guess my concern is largely around the fact that
> > it
> > > > > won't
> > > > > > be
> > > > > > > possible to distinguish between the overloaded methods' use
> cases
> > > > just
> > > > > > from
> > > > > > > the method signatures. I agree that naming is going to be
> > difficult
> > > > > here,
> > > > > > > but I think that having two sets of `SinkTask::openXyz` /
> > > > > > > `SinkTask::closeXyz` methods will be less complicated to
> > understand
> > > > > from
> > > > > > a
> > > > > > > connector developer perspective (as compared to overloaded
> > methods
> > > > with
> > > > > > > only differing documentation). Of your suggested options, I
> think
> > > > > > > `openPreTransform` / `openPostTransform` are the most
> > > comprehensible
> > > > > > ones.
> > > > > > >
> > > > > > > > BTW, I wouldn't say that we can't make assumptions
> > > > > > > > about the relationships between pre- and post-transformation
> > > > > > > >  topic partitions.
> > > > > > >
> > > > > > > I meant that the framework wouldn't be able to
> deterministically
> > > know
> > > > > > when
> > > > > > > to close a post-transform topic partition given that SMTs could
> > use
> > > > > > > per-record data / metadata to manipulate the topic names as and
> > how
> > > > > > > required (which supports the suggestion to use an eviction
> policy
> > > > based
> > > > > > > mechanism to call SinkTask::close for post-transform topic
> > > > partitions).
> > > > > > >
> > > > > > > > We might utilize a policy that assumes a deterministic
> > > > > > > > mapping from the former to the latter, for example.
> > > > > > >
> > > > > > > Wouldn't this be making the assumption that SMTs only use the
> > topic
> > > > > name
> > > > > > > itself and no other data / metadata while computing the new
> topic
> > > > name?
> > > > > > Are
> > > > > > > you suggesting that since this assumption could work for a
> > majority
> > > > of
> > > > > > > SMTs, it might be more efficient overall in terms of reducing
> the
> > > > > number
> > > > > > of
> > > > > > > "false-positive" calls to `SinkTask::closePostTransform` (and
> > we'll
> > > > > also
> > > > > > be
> > > > > > > able to call `SinkTask::closePostTransform` immediately after
> > topic
> > > > > > > partitions are revoked from the consumer)? I was thinking
> > something
> > > > > more
> > > > > > > generic along the lines of a simple time based eviction policy
> > that
> > > > > > > wouldn't be making any assumptions regarding the SMT
> > > implementations.
> > > > > > > Either way, I do like your earlier suggestion of keeping this
> > logic
> > > > > > > internal and not painting ourselves into a corner by promising
> > any
> > > > > > > particular behavior in the KIP.
> > > > > > >
> > > > > > > Thanks,
> > > > > > > Yash
> > > > > > >
> > > > > > > On Tue, Feb 14, 2023 at 1:08 AM Chris Egerton
> > > > <chrise@aiven.io.invalid
> > > > > >
> > > > > > > wrote:
> > > > > > >
> > > > > > > > Hi Yash,
> > > > > > > >
> > > > > > > > I think the key difference between adding methods/overloads
> > > related
> > > > > to
> > > > > > > > SinkTask::open/SinkTask::close and SinkTask::put is that this
> > > isn't
> > > > > > > > auxiliary information that may or may not be useful to
> > connector
> > > > > > > > developers. It's actually critical for them to understand the
> > > > > > difference
> > > > > > > > between the two concepts here, even if they look very
> similar.
> > > And
> > > > > > yes, I
> > > > > > > > do believe that switching from pre-transform to
> post-transform
> > > > topic
> > > > > > > > partitions is too big a change in behavior here. Plus, if a
> > > > connector
> > > > > > is
> > > > > > > > intentionally designed to use pre-transformation topic
> > partitions
> > > > in
> > > > > > its
> > > > > > > > open/close methods, wouldn't we just be trading one form of
> the
> > > > > problem
> > > > > > > for
> > > > > > > > another by making this switch?
> > > > > > > >
> > > > > > > > One possible alternative to overloading the existing methods
> is
> > > to
> > > > > > split
> > > > > > > > SinkTask::open into openOriginal (or possibly openPhysical or
> > > > > > > > openPreTransform) and openTransformed (or openLogical or
> > > > > > > > openPostTransform), with a similar change for
> SinkTask::close.
> > > The
> > > > > > > default
> > > > > > > > implementation for SinkTask::openOriginal can be to call
> > > > > > SinkTask::open,
> > > > > > > > and the same can go for SinkTask::close. However, I prefer
> > > > > overloading
> > > > > > > the
> > > > > > > > existing methods since this alternative increases complexity
> > and
> > > > none
> > > > > > of
> > > > > > > > the names are very informative.
> > > > > > > >
> > > > > > > > BTW, I wouldn't say that we can't make assumptions about the
> > > > > > > relationships
> > > > > > > > between pre- and post-transformation topic partitions. We
> might
> > > > > > utilize a
> > > > > > > > policy that assumes a deterministic mapping from the former
> to
> > > the
> > > > > > > latter,
> > > > > > > > for example. The distinction I'd draw is that the assumptions
> > we
> > > > make
> > > > > > can
> > > > > > > > and probably should favor some cases in terms of performance
> > > (i.e.,
> > > > > > > > reducing the number of unnecessary calls to close/open over a
> > > given
> > > > > > sink
> > > > > > > > task's lifetime), but should not lead to guaranteed resource
> > > leaks
> > > > or
> > > > > > > > failure to obey API contract in any cases.
> > > > > > > >
> > > > > > > > Cheers,
> > > > > > > >
> > > > > > > > Chris
> > > > > > > >
> > > > > > > > On Mon, Feb 13, 2023 at 10:54 AM Yash Mayya <
> > > yash.mayya@gmail.com>
> > > > > > > wrote:
> > > > > > > >
> > > > > > > > > Hi Chris,
> > > > > > > > >
> > > > > > > > > > especially if connectors are intentionally designed
> around
> > > > > > > > > > original topic partitions instead of transformed ones.
> > > > > > > > >
> > > > > > > > > Ha, that's a good point and reminds me of Hyrum's Law [1]
> :)
> > > > > > > > >
> > > > > > > > > > I think we have to provide connector developers with some
> > > > > > > > > > way to differentiate between the two, but maybe there's a
> > way
> > > > > > > > > >  to do this that I haven't thought of yet
> > > > > > > > >
> > > > > > > > > I can't think of a better way to do this either; would
> > invoking
> > > > the
> > > > > > > > > existing `SinkTask::open` and `SinkTask::close` methods
> with
> > > > > > > > post-transform
> > > > > > > > > topic partitions instead of pre-transform topic partitions
> > not
> > > be
> > > > > > > > > acceptable even in a minor / major AK release? I feel like
> > the
> > > > > > proposed
> > > > > > > > > approach of adding overloaded `SinkTask::open` /
> > > > `SinkTask::close`
> > > > > > > > methods
> > > > > > > > > to differentiate between pre-transform and post-transform
> > topic
> > > > > > > > partitions
> > > > > > > > > has similar pitfalls to the idea of the overloaded
> > > > `SinkTask::put`
> > > > > > > method
> > > > > > > > > we discarded earlier.
> > > > > > > > >
> > > > > > > > > > Either way, I'm glad that the general idea of a cache and
> > > > > > > > > > eviction policy for SinkTask::close seem reasonable; if
> > > > > > > > > > we decide to go this route, it might make sense for the
> KIP
> > > > > > > > > > to include an outline of one or more high-level
> strategies
> > > > > > > > > > we might take, but without promising any particular
> > behavior
> > > > > > > > > > beyond occasionally calling SinkTask::close for
> > > post-transform
> > > > > > > > > > topic partitions. I'm hoping that this logic can stay
> > > internal,
> > > > > > > > > > and by notpainting ourselves into a corner with the KIP,
> we
> > > > > > > > > > give ourselves leeway to tweak it in the future if
> > necessary
> > > > > > > > > > without filing another KIP or introducing a pluggable
> > > > interface.
> > > > > > > > >
> > > > > > > > > Thanks, that's a good idea. Given the flexibility of SMTs,
> > the
> > > > > > > framework
> > > > > > > > > can't really make any assumptions around topic partitions
> > post
> > > > > > > > > transformation nor does it have any way to definitively get
> > any
> > > > > such
> > > > > > > > > information from transformations which is why the idea of a
> > > cache
> > > > > > with
> > > > > > > an
> > > > > > > > > eviction policy makes perfect sense!
> > > > > > > > >
> > > > > > > > > [1] - https://www.hyrumslaw.com/
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > Thanks,
> > > > > > > > > Yash
> > > > > > > > >
> > > > > > > > > On Thu, Feb 9, 2023 at 9:38 PM Chris Egerton
> > > > > <chrise@aiven.io.invalid
> > > > > > >
> > > > > > > > > wrote:
> > > > > > > > >
> > > > > > > > > > Hi Yash,
> > > > > > > > > >
> > > > > > > > > > > So it looks like with the current state of affairs,
> sink
> > > > tasks
> > > > > > that
> > > > > > > > > only
> > > > > > > > > > instantiate writers in the SinkTask::open method (and
> don't
> > > do
> > > > > the
> > > > > > > lazy
> > > > > > > > > > instantiation in SinkTask::put that you mentioned) might
> > fail
> > > > > when
> > > > > > > used
> > > > > > > > > > with topic/partition mutating SMTs even if they don't do
> > any
> > > > > > > > asynchronous
> > > > > > > > > > processing?
> > > > > > > > > >
> > > > > > > > > > Yep, exactly 👍
> > > > > > > > > >
> > > > > > > > > > > What do you think about retaining just the existing
> > methods
> > > > > > > > > > but changing when they're called in the Connect runtime?
> > For
> > > > > > > instance,
> > > > > > > > > > instead of calling SinkTask::open after partition
> > assignment
> > > > > post a
> > > > > > > > > > consumer group rebalance, we could cache the currently
> > "seen"
> > > > > topic
> > > > > > > > > > partitions (post transformation) and before each call to
> > > > > > > SinkTask::put
> > > > > > > > > > check whether there's any new "unseen" topic partitions,
> > and
> > > if
> > > > > so
> > > > > > > call
> > > > > > > > > > SinkTask::open (and also update the cache of course).
> > > > > > > > > >
> > > > > > > > > > IMO the issue here is that it's a drastic change in
> > behavior
> > > to
> > > > > > start
> > > > > > > > > > invoking SinkTask::open and SinkTask::close with
> > > post-transform
> > > > > > topic
> > > > > > > > > > partitions instead of pre-transform, especially if
> > connectors
> > > > are
> > > > > > > > > > intentionally designed around original topic partitions
> > > instead
> > > > > of
> > > > > > > > > > transformed ones. I think we have to provide connector
> > > > developers
> > > > > > > with
> > > > > > > > > some
> > > > > > > > > > way to differentiate between the two, but maybe there's a
> > way
> > > > to
> > > > > do
> > > > > > > > this
> > > > > > > > > > that I haven't thought of yet. Interested to hear your
> > > > thoughts.
> > > > > > > > > >
> > > > > > > > > > Either way, I'm glad that the general idea of a cache and
> > > > > eviction
> > > > > > > > policy
> > > > > > > > > > for SinkTask::close seem reasonable; if we decide to go
> > this
> > > > > route,
> > > > > > > it
> > > > > > > > > > might make sense for the KIP to include an outline of one
> > or
> > > > more
> > > > > > > > > > high-level strategies we might take, but without
> promising
> > > any
> > > > > > > > particular
> > > > > > > > > > behavior beyond occasionally calling SinkTask::close for
> > > > > > > post-transform
> > > > > > > > > > topic partitions. I'm hoping that this logic can stay
> > > internal,
> > > > > and
> > > > > > > by
> > > > > > > > > not
> > > > > > > > > > painting ourselves into a corner with the KIP, we give
> > > > ourselves
> > > > > > > leeway
> > > > > > > > > to
> > > > > > > > > > tweak it in the future if necessary without filing
> another
> > > KIP
> > > > or
> > > > > > > > > > introducing a pluggable interface.
> > > > > > > > > >
> > > > > > > > > > Cheers,
> > > > > > > > > >
> > > > > > > > > > Chris
> > > > > > > > > >
> > > > > > > > > > On Thu, Feb 9, 2023 at 7:39 AM Yash Mayya <
> > > > yash.mayya@gmail.com>
> > > > > > > > wrote:
> > > > > > > > > >
> > > > > > > > > > > Hi Chris,
> > > > > > > > > > >
> > > > > > > > > > > Thanks for the feedback.
> > > > > > > > > > >
> > > > > > > > > > > 1) That's a fair point; while I did scan everything
> > > publicly
> > > > > > > > available
> > > > > > > > > on
> > > > > > > > > > > GitHub, you're right in that it won't cover all
> possible
> > > SMTs
> > > > > > that
> > > > > > > > are
> > > > > > > > > > out
> > > > > > > > > > > there. Thanks for the example use-case as well, I've
> > > updated
> > > > > the
> > > > > > > KIP
> > > > > > > > to
> > > > > > > > > > add
> > > > > > > > > > > the two new proposed methods.
> > > > > > > > > > >
> > > > > > > > > > > 2) So it looks like with the current state of affairs,
> > sink
> > > > > tasks
> > > > > > > > that
> > > > > > > > > > only
> > > > > > > > > > > instantiate writers in the SinkTask::open method (and
> > don't
> > > > do
> > > > > > the
> > > > > > > > lazy
> > > > > > > > > > > instantiation in SinkTask::put that you mentioned)
> might
> > > fail
> > > > > > when
> > > > > > > > used
> > > > > > > > > > > with topic/partition mutating SMTs even if they don't
> do
> > > any
> > > > > > > > > asynchronous
> > > > > > > > > > > processing? Since they could encounter records in
> > > > SinkTask::put
> > > > > > > with
> > > > > > > > > > > topics/partitions that they might not have created
> > writers
> > > > for.
> > > > > > > > Thanks
> > > > > > > > > > for
> > > > > > > > > > > pointing this out, it's definitely another
> > incompatibility
> > > > that
> > > > > > > needs
> > > > > > > > > to
> > > > > > > > > > be
> > > > > > > > > > > called out and fixed. The overloaded method approach is
> > > > > > > interesting,
> > > > > > > > > but
> > > > > > > > > > > comes with the caveat of yet more new methods that will
> > > need
> > > > to
> > > > > > be
> > > > > > > > > > > implemented by existing connectors if they want to make
> > use
> > > > of
> > > > > > this
> > > > > > > > new
> > > > > > > > > > > functionality. What do you think about retaining just
> the
> > > > > > existing
> > > > > > > > > > methods
> > > > > > > > > > > but changing when they're called in the Connect
> runtime?
> > > For
> > > > > > > > instance,
> > > > > > > > > > > instead of calling SinkTask::open after partition
> > > assignment
> > > > > > post a
> > > > > > > > > > > consumer group rebalance, we could cache the currently
> > > "seen"
> > > > > > topic
> > > > > > > > > > > partitions (post transformation) and before each call
> to
> > > > > > > > SinkTask::put
> > > > > > > > > > > check whether there's any new "unseen" topic
> partitions,
> > > and
> > > > if
> > > > > > so
> > > > > > > > call
> > > > > > > > > > > SinkTask::open (and also update the cache of course). I
> > > don't
> > > > > > think
> > > > > > > > > this
> > > > > > > > > > > would break the existing contract with sink tasks where
> > > > > > > > SinkTask::open
> > > > > > > > > is
> > > > > > > > > > > expected to be called for a topic partition before any
> > > > records
> > > > > > from
> > > > > > > > the
> > > > > > > > > > > topic partition are sent via SinkTask::put? The
> > > > SinkTask::close
> > > > > > > case
> > > > > > > > > is a
> > > > > > > > > > > lot trickier however, and would require some sort of
> > cache
> > > > > > eviction
> > > > > > > > > > policy
> > > > > > > > > > > that would be deemed appropriate as you pointed out
> too.
> > > > > > > > > > >
> > > > > > > > > > > Thanks,
> > > > > > > > > > > Yash
> > > > > > > > > > >
> > > > > > > > > > > On Mon, Feb 6, 2023 at 11:27 PM Chris Egerton
> > > > > > > > <chrise@aiven.io.invalid
> > > > > > > > > >
> > > > > > > > > > > wrote:
> > > > > > > > > > >
> > > > > > > > > > > > Hi Yash,
> > > > > > > > > > > >
> > > > > > > > > > > > I've had some time to think on this KIP and I think
> I'm
> > > in
> > > > > > > > agreement
> > > > > > > > > > > about
> > > > > > > > > > > > not blocking it on an official compatibility library
> or
> > > > > adding
> > > > > > > the
> > > > > > > > > > "ack"
> > > > > > > > > > > > API for sink records.
> > > > > > > > > > > >
> > > > > > > > > > > > I only have two more thoughts:
> > > > > > > > > > > >
> > > > > > > > > > > > 1. Because it is possible to manipulate sink record
> > > > > partitions
> > > > > > > and
> > > > > > > > > > > offsets
> > > > > > > > > > > > with the current API we provide for transformations,
> I
> > > > still
> > > > > > > > believe
> > > > > > > > > > > > methods should be added to the SinkRecord class to
> > expose
> > > > the
> > > > > > > > > original
> > > > > > > > > > > > partition and offset, not just the original topic.
> The
> > > > > > additional
> > > > > > > > > > > cognitive
> > > > > > > > > > > > burden from these two methods is going to be minimal
> > > > anyways;
> > > > > > > once
> > > > > > > > > > users
> > > > > > > > > > > > understand the difference between the transformed
> topic
> > > > name
> > > > > > and
> > > > > > > > the
> > > > > > > > > > > > original one, it's going to be trivial for them to
> > > > understand
> > > > > > how
> > > > > > > > > that
> > > > > > > > > > > same
> > > > > > > > > > > > difference applies for partitions and offsets. It's
> not
> > > > > enough
> > > > > > to
> > > > > > > > > scan
> > > > > > > > > > > the
> > > > > > > > > > > > set of SMTs provided out of the box with Connect,
> ones
> > > > > > developed
> > > > > > > by
> > > > > > > > > > > > Confluent, or even everything available on GitHub,
> > since
> > > > > there
> > > > > > > may
> > > > > > > > be
> > > > > > > > > > > > closed-source projects out there that rely on this
> > > ability.
> > > > > One
> > > > > > > > > > potential
> > > > > > > > > > > > use case could be re-routing partitions between Kafka
> > and
> > > > > some
> > > > > > > > other
> > > > > > > > > > > > sharded system.
> > > > > > > > > > > >
> > > > > > > > > > > > 2. We still have to address the SinkTask::open [1]
> and
> > > > > > > > > SinkTask::close
> > > > > > > > > > > [2]
> > > > > > > > > > > > methods. If a connector writes to the external system
> > > using
> > > > > the
> > > > > > > > > > > transformed
> > > > > > > > > > > > topic partitions it reads from Kafka, then it's
> > possible
> > > > for
> > > > > > the
> > > > > > > > > > > connector
> > > > > > > > > > > > to lazily instantiate writers for topic partitions as
> > it
> > > > > > > encounters
> > > > > > > > > > them
> > > > > > > > > > > > from records provided in SinkTask::put. However,
> > > connectors
> > > > > > also
> > > > > > > > > need a
> > > > > > > > > > > way
> > > > > > > > > > > > to de-allocate those writers (and the resources used
> by
> > > > them)
> > > > > > > over
> > > > > > > > > > time,
> > > > > > > > > > > > which they can't do as easily. One possible approach
> > here
> > > > is
> > > > > to
> > > > > > > > > > overload
> > > > > > > > > > > > SinkTask::open and SinkTask::close with variants that
> > > > > > distinguish
> > > > > > > > > > between
> > > > > > > > > > > > transformed and original topic partitions, and
> default
> > to
> > > > > > > invoking
> > > > > > > > > the
> > > > > > > > > > > > existing methods with just the original topic
> > partitions.
> > > > We
> > > > > > > would
> > > > > > > > > then
> > > > > > > > > > > > have several options for how the Connect runtime can
> > > invoke
> > > > > > these
> > > > > > > > > > > methods,
> > > > > > > > > > > > but in general, an approach that guarantees that
> tasks
> > > are
> > > > > > > notified
> > > > > > > > > of
> > > > > > > > > > > > transformed topic partitions in SinkTask::open before
> > any
> > > > > > records
> > > > > > > > for
> > > > > > > > > > > that
> > > > > > > > > > > > partition are given to it in SinkTask::put, and
> makes a
> > > > > > > best-effort
> > > > > > > > > > > attempt
> > > > > > > > > > > > to close transformed topic partitions that appear to
> no
> > > > > longer
> > > > > > be
> > > > > > > > in
> > > > > > > > > > use
> > > > > > > > > > > > based on some eviction policy, would probably be
> > > > sufficient.
> > > > > > > > > > > >
> > > > > > > > > > > > [1] -
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://kafka.apache.org/33/javadoc/org/apache/kafka/connect/sink/SinkTask.html#open(java.util.Collection)
> > > > > > > > > > > > [2] -
> > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://kafka.apache.org/33/javadoc/org/apache/kafka/connect/sink/SinkTask.html#close(java.util.Collection)
> > > > > > > > > > > >
> > > > > > > > > > > > Cheers,
> > > > > > > > > > > >
> > > > > > > > > > > > Chris
> > > > > > > > > > > >
> > > > > > > > > > > > On Sat, Nov 5, 2022 at 5:46 AM Yash Mayya <
> > > > > > yash.mayya@gmail.com>
> > > > > > > > > > wrote:
> > > > > > > > > > > >
> > > > > > > > > > > > > Hi Chris,
> > > > > > > > > > > > >
> > > > > > > > > > > > > Thanks a lot for your inputs!
> > > > > > > > > > > > >
> > > > > > > > > > > > > > would provide a simple, clean interface for
> > > developers
> > > > to
> > > > > > > > > determine
> > > > > > > > > > > > > > which features are supported by the version of
> the
> > > > > Connect
> > > > > > > > > runtime
> > > > > > > > > > > > > > that their plugin has been deployed onto
> > > > > > > > > > > > >
> > > > > > > > > > > > > I do like the idea of having such a public
> > > compatibility
> > > > > > > library
> > > > > > > > -
> > > > > > > > > I
> > > > > > > > > > > > think
> > > > > > > > > > > > > it would remove a lot of restrictions from
> framework
> > > > > > > development
> > > > > > > > if
> > > > > > > > > > it
> > > > > > > > > > > > were
> > > > > > > > > > > > > to be widely adopted.
> > > > > > > > > > > > >
> > > > > > > > > > > > > > we might consider adding an API to "ack" sink
> > records
> > > > > > > > > > > > >
> > > > > > > > > > > > > I agree that this does seem like a more intuitive
> and
> > > > clean
> > > > > > > API,
> > > > > > > > > but
> > > > > > > > > > > I'm
> > > > > > > > > > > > > concerned about the backward compatibility headache
> > > we'd
> > > > be
> > > > > > > > > imposing
> > > > > > > > > > on
> > > > > > > > > > > > all
> > > > > > > > > > > > > existing sink connectors. Connector developers will
> > > have
> > > > to
> > > > > > > > > maintain
> > > > > > > > > > > two
> > > > > > > > > > > > > separate ways of doing offset management if they
> want
> > > to
> > > > > use
> > > > > > > the
> > > > > > > > > new
> > > > > > > > > > > API
> > > > > > > > > > > > > but continue supporting older versions of Kafka
> > > Connect.
> > > > > > > > > > > > >
> > > > > > > > > > > > > For now, I've reverted the KIP to the previous
> > > iteration
> > > > > > which
> > > > > > > > > > proposed
> > > > > > > > > > > > the
> > > > > > > > > > > > > addition of a new `SinkRecord` method to obtain the
> > > > > original
> > > > > > > > Kafka
> > > > > > > > > > > topic
> > > > > > > > > > > > > pre-transformation. One thing to note is that I've
> > > > removed
> > > > > > the
> > > > > > > > > method
> > > > > > > > > > > for
> > > > > > > > > > > > > obtaining the original Kafka partition after a
> > cursory
> > > > > search
> > > > > > > > > showed
> > > > > > > > > > > that
> > > > > > > > > > > > > use cases for partition modifying SMTs are
> primarily
> > on
> > > > the
> > > > > > > > source
> > > > > > > > > > > > > connector side.
> > > > > > > > > > > > >
> > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > Yash
> > > > > > > > > > > > >
> > > > > > > > > > > > > On Tue, Nov 1, 2022 at 9:22 PM Chris Egerton
> > > > > > > > > <chrise@aiven.io.invalid
> > > > > > > > > > >
> > > > > > > > > > > > > wrote:
> > > > > > > > > > > > >
> > > > > > > > > > > > > > Hi all,
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > I have more comments I'd like to make on this KIP
> > > when
> > > > I
> > > > > > have
> > > > > > > > > time
> > > > > > > > > > > > (sorry
> > > > > > > > > > > > > > for the delay, Yash, and thanks for your
> > patience!),
> > > > but
> > > > > I
> > > > > > > did
> > > > > > > > > want
> > > > > > > > > > > to
> > > > > > > > > > > > > > chime in and say that I'm also not sure about
> > > > overloading
> > > > > > > > > > > > SinkTask::put.
> > > > > > > > > > > > > I
> > > > > > > > > > > > > > share the concerns about creating an intuitive,
> > > simple
> > > > > API
> > > > > > > that
> > > > > > > > > > Yash
> > > > > > > > > > > > has
> > > > > > > > > > > > > > raised. In addition, this approach doesn't seem
> > very
> > > > > > > > > > > sustainable--what
> > > > > > > > > > > > do
> > > > > > > > > > > > > > we do if we encounter another case in the future
> > that
> > > > > would
> > > > > > > > > > warrant a
> > > > > > > > > > > > > > similar solution? We probably don't want to
> create
> > > > three,
> > > > > > > four,
> > > > > > > > > > etc.
> > > > > > > > > > > > > > overloaded variants of the method, each of which
> > > would
> > > > > have
> > > > > > > to
> > > > > > > > be
> > > > > > > > > > > > > > implemented by connector developers who want to
> > both
> > > > > > leverage
> > > > > > > > the
> > > > > > > > > > > > latest
> > > > > > > > > > > > > > and greatest connector APIs and maintain
> > > compatibility
> > > > > with
> > > > > > > > > connect
> > > > > > > > > > > > > > Clusters running older versions.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > I haven't been able to flesh this out into a
> design
> > > > worth
> > > > > > > > > > publishing
> > > > > > > > > > > in
> > > > > > > > > > > > > its
> > > > > > > > > > > > > > own KIP yet, but one alternative I've pitched to
> a
> > > few
> > > > > > people
> > > > > > > > > with
> > > > > > > > > > > > > > generally positive interest has been to develop
> an
> > > > > official
> > > > > > > > > > > > compatibility
> > > > > > > > > > > > > > library for Connect developers. This library
> would
> > be
> > > > > > > released
> > > > > > > > as
> > > > > > > > > > its
> > > > > > > > > > > > own
> > > > > > > > > > > > > > Maven artifact (separate from connect-api,
> > > > > connect-runtime,
> > > > > > > > etc.)
> > > > > > > > > > and
> > > > > > > > > > > > > would
> > > > > > > > > > > > > > provide a simple, clean interface for developers
> to
> > > > > > determine
> > > > > > > > > which
> > > > > > > > > > > > > > features are supported by the version of the
> > Connect
> > > > > > runtime
> > > > > > > > that
> > > > > > > > > > > their
> > > > > > > > > > > > > > plugin has been deployed onto. Under the hood,
> this
> > > > > library
> > > > > > > > might
> > > > > > > > > > use
> > > > > > > > > > > > > > reflection to determine whether classes, methods,
> > > etc.
> > > > > are
> > > > > > > > > > available,
> > > > > > > > > > > > but
> > > > > > > > > > > > > > the developer wouldn't have to do anything more
> > than
> > > > > check
> > > > > > > (for
> > > > > > > > > > > > example)
> > > > > > > > > > > > > >
> > `Features.SINK_TASK_ERRANT_RECORD_REPORTER.enabled()`
> > > > to
> > > > > > know
> > > > > > > > at
> > > > > > > > > > any
> > > > > > > > > > > > > point
> > > > > > > > > > > > > > in the lifetime of their connector/task whether
> > that
> > > > > > feature
> > > > > > > is
> > > > > > > > > > > > provided
> > > > > > > > > > > > > by
> > > > > > > > > > > > > > the runtime.
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > One other high-level comment: this doesn't
> address
> > > > every
> > > > > > > case,
> > > > > > > > > but
> > > > > > > > > > we
> > > > > > > > > > > > > might
> > > > > > > > > > > > > > consider adding an API to "ack" sink records.
> This
> > > > could
> > > > > > use
> > > > > > > > the
> > > > > > > > > > > > > > SubmittedRecords class [1] (with some slight
> > tweaks)
> > > > > under
> > > > > > > the
> > > > > > > > > hood
> > > > > > > > > > > to
> > > > > > > > > > > > > > track the latest-acked offset for each topic
> > > partition.
> > > > > > This
> > > > > > > > way,
> > > > > > > > > > > > > connector
> > > > > > > > > > > > > > developers won't be responsible for tracking
> > offsets
> > > at
> > > > > all
> > > > > > > in
> > > > > > > > > > their
> > > > > > > > > > > > sink
> > > > > > > > > > > > > > tasks (eliminating issues with the accuracy of
> > > > > > > > > post-transformation
> > > > > > > > > > > > T/P/O
> > > > > > > > > > > > > > sink record information), and they'll only have
> to
> > > > notify
> > > > > > the
> > > > > > > > > > Connect
> > > > > > > > > > > > > > framework when a record has been successfully
> > > > dispatched
> > > > > to
> > > > > > > the
> > > > > > > > > > > > external
> > > > > > > > > > > > > > system. This provides a cleaner, friendlier API,
> > and
> > > > also
> > > > > > > > enables
> > > > > > > > > > > more
> > > > > > > > > > > > > > fine-grained metrics like the ones proposed in
> > > KIP-767
> > > > > [2].
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > [1] -
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://github.com/apache/kafka/blob/9ab140d5419d735baae45aff56ffce7f5622744f/connect/runtime/src/main/java/org/apache/kafka/connect/runtime/SubmittedRecords.java
> > > > > > > > > > > > > > [2] -
> > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-767%3A+Connect+Latency+Metrics
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Cheers,
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > Chris
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > On Tue, Nov 1, 2022 at 11:21 AM Yash Mayya <
> > > > > > > > yash.mayya@gmail.com
> > > > > > > > > >
> > > > > > > > > > > > wrote:
> > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Hi Randall,
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > It's been a while for this one but the more I
> > think
> > > > > about
> > > > > > > it,
> > > > > > > > > the
> > > > > > > > > > > > more
> > > > > > > > > > > > > I
> > > > > > > > > > > > > > > feel like the current approach with a new
> > > overloaded
> > > > > > > > > > > `SinkTask::put`
> > > > > > > > > > > > > > method
> > > > > > > > > > > > > > > might not be optimal. We're trying to fix a
> > pretty
> > > > > corner
> > > > > > > > case
> > > > > > > > > > bug
> > > > > > > > > > > > here
> > > > > > > > > > > > > > > (usage of topic mutating SMTs with sink
> > connectors
> > > > that
> > > > > > do
> > > > > > > > > their
> > > > > > > > > > > own
> > > > > > > > > > > > > > offset
> > > > > > > > > > > > > > > tracking) and I'm not sure that warrants a
> change
> > > to
> > > > > > such a
> > > > > > > > > > central
> > > > > > > > > > > > > > > interface method. The new `SinkTask::put`
> method
> > > just
> > > > > > seems
> > > > > > > > > > > somewhat
> > > > > > > > > > > > > odd
> > > > > > > > > > > > > > > and it may not be very understandable for a new
> > > > reader
> > > > > -
> > > > > > I
> > > > > > > > > don't
> > > > > > > > > > > > think
> > > > > > > > > > > > > > this
> > > > > > > > > > > > > > > should be the case for a public interface
> method.
> > > > > > > > Furthermore,
> > > > > > > > > > even
> > > > > > > > > > > > > with
> > > > > > > > > > > > > > > elaborate documentation in place, I'm not sure
> if
> > > > it'll
> > > > > > be
> > > > > > > > very
> > > > > > > > > > > > obvious
> > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > most people what the purpose of having these
> two
> > > > `put`
> > > > > > > > methods
> > > > > > > > > is
> > > > > > > > > > > and
> > > > > > > > > > > > > how
> > > > > > > > > > > > > > > they should be used by sink task
> implementations.
> > > > What
> > > > > do
> > > > > > > you
> > > > > > > > > > > think?
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > Yash
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > On Mon, Oct 10, 2022 at 9:33 PM Yash Mayya <
> > > > > > > > > yash.mayya@gmail.com
> > > > > > > > > > >
> > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Hi Randall,
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Thanks a lot for your valuable feedback so
> far!
> > > > I've
> > > > > > > > updated
> > > > > > > > > > the
> > > > > > > > > > > > KIP
> > > > > > > > > > > > > > > based
> > > > > > > > > > > > > > > > on our discussion above. Could you please
> take
> > > > > another
> > > > > > > > look?
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > Thanks,
> > > > > > > > > > > > > > > > Yash
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > > On Tue, Oct 4, 2022 at 12:40 AM Randall
> Hauch <
> > > > > > > > > > rhauch@gmail.com>
> > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >> On Mon, Oct 3, 2022 at 11:45 AM Yash Mayya <
> > > > > > > > > > > yash.mayya@gmail.com>
> > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >> > Hi Randall,
> > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > >> > Thanks for elaborating. I think these are
> > all
> > > > very
> > > > > > > good
> > > > > > > > > > points
> > > > > > > > > > > > > and I
> > > > > > > > > > > > > > > see
> > > > > > > > > > > > > > > >> > why the overloaded `SinkTask::put` method
> > is a
> > > > > > cleaner
> > > > > > > > > > > solution
> > > > > > > > > > > > > > > overall.
> > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > >> > > public void put(Collection<SinkRecord>
> > > > records,
> > > > > > > > > > > > Map<SinkRecord,
> > > > > > > > > > > > > > > >> > TopicPartition> updatedTopicPartitions)
> > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > >> > I think this should be
> > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > >> > `public void put(Collection<SinkRecord>
> > > records,
> > > > > > > > > > > Map<SinkRecord,
> > > > > > > > > > > > > > > >> > TopicPartition> originalTopicPartitions)`
> > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > >> > instead because the sink records
> themselves
> > > have
> > > > > the
> > > > > > > > > updated
> > > > > > > > > > > > topic
> > > > > > > > > > > > > > > >> > partitions (i.e. after all transformations
> > > have
> > > > > been
> > > > > > > > > > applied)
> > > > > > > > > > > > and
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > >> KIP
> > > > > > > > > > > > > > > >> > is proposing a way for the tasks to be
> able
> > to
> > > > > > access
> > > > > > > > the
> > > > > > > > > > > > original
> > > > > > > > > > > > > > > topic
> > > > > > > > > > > > > > > >> > partition (i.e. before transformations
> have
> > > been
> > > > > > > > applied).
> > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >> Sounds good.
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > >> > > Of course, if the developer does not
> need
> > > > > separate
> > > > > > > > > > methods,
> > > > > > > > > > > > they
> > > > > > > > > > > > > > can
> > > > > > > > > > > > > > > >> > easily have the older `put` method simply
> > > > delegate
> > > > > > to
> > > > > > > > the
> > > > > > > > > > > newer
> > > > > > > > > > > > > > > method.
> > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > >> > If the developer does not need separate
> > > methods
> > > > > > (i.e.
> > > > > > > > they
> > > > > > > > > > > don't
> > > > > > > > > > > > > > need
> > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > >> > use this new addition), they can simply
> > > continue
> > > > > > > > > > implementing
> > > > > > > > > > > > just
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > >> > older `put` method right?
> > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >> Correct. We should update the JavaDoc of
> both
> > > > > methods
> > > > > > to
> > > > > > > > > make
> > > > > > > > > > > this
> > > > > > > > > > > > > > > clear,
> > > > > > > > > > > > > > > >> and in general how the two methods should
> are
> > > used
> > > > > and
> > > > > > > > > should
> > > > > > > > > > be
> > > > > > > > > > > > > > > >> implemented. That can be part of the PR, and
> > the
> > > > KIP
> > > > > > > > doesn't
> > > > > > > > > > > need
> > > > > > > > > > > > > this
> > > > > > > > > > > > > > > >> wording.
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > >> > > Finally, this gives us a roadmap for
> > > > > *eventually*
> > > > > > > > > > > deprecating
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > >> older
> > > > > > > > > > > > > > > >> > method, once the Connect runtime versions
> > > > without
> > > > > > this
> > > > > > > > > > change
> > > > > > > > > > > > are
> > > > > > > > > > > > > > old
> > > > > > > > > > > > > > > >> > enough.
> > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > >> > I'm not sure we'd ever want to deprecate
> the
> > > > older
> > > > > > > > method.
> > > > > > > > > > > Most
> > > > > > > > > > > > > > common
> > > > > > > > > > > > > > > >> sink
> > > > > > > > > > > > > > > >> > connector implementations do not do their
> > own
> > > > > offset
> > > > > > > > > > tracking
> > > > > > > > > > > > with
> > > > > > > > > > > > > > > >> > asynchronous processing and will probably
> > > never
> > > > > > have a
> > > > > > > > > need
> > > > > > > > > > > for
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > >> > additional parameter `Map<SinkRecord,
> > > > > > TopicPartition>
> > > > > > > > > > > > > > > >> > originalTopicPartitions` in the proposed
> new
> > > > `put`
> > > > > > > > method.
> > > > > > > > > > > These
> > > > > > > > > > > > > > > >> connectors
> > > > > > > > > > > > > > > >> > can continue implementing only the
> existing
> > > > > > > > > `SinkTask::put`
> > > > > > > > > > > > method
> > > > > > > > > > > > > > > which
> > > > > > > > > > > > > > > >> > will be called by the default
> implementation
> > > of
> > > > > the
> > > > > > > > newer
> > > > > > > > > > > > > overloaded
> > > > > > > > > > > > > > > >> `put`
> > > > > > > > > > > > > > > >> > method.
> > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >> +1
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > >> > > the pre-commit methods use the same
> > > > > > > > `Map<TopicPartition,
> > > > > > > > > > > > > > > >> > OffsetAndMetadata> currentOffsets` data
> > > > structure
> > > > > > I'm
> > > > > > > > > > > suggesting
> > > > > > > > > > > > > be
> > > > > > > > > > > > > > > >> used.
> > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > >> > The data structure you're suggesting be
> used
> > > is
> > > > a
> > > > > > > > > > > > `Map<SinkRecord,
> > > > > > > > > > > > > > > >> > TopicPartition>` which will map
> `SinkRecord`
> > > > > objects
> > > > > > > to
> > > > > > > > > the
> > > > > > > > > > > > > original
> > > > > > > > > > > > > > > >> topic
> > > > > > > > > > > > > > > >> > partition of the corresponding
> > > `ConsumerRecord`
> > > > > > right?
> > > > > > > > To
> > > > > > > > > > > > clarify,
> > > > > > > > > > > > > > > this
> > > > > > > > > > > > > > > >> is
> > > > > > > > > > > > > > > >> > a new data structure that will need to be
> > > > managed
> > > > > in
> > > > > > > the
> > > > > > > > > > > > > > > >> `WorkerSinkTask`.
> > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >> Ah, you're right. Thanks for the correction.
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >> Best regards,
> > > > > > > > > > > > > > > >> Randall
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >> > Thanks,
> > > > > > > > > > > > > > > >> > Yash
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >> > On Mon, Oct 3, 2022 at 1:20 AM Randall
> > Hauch <
> > > > > > > > > > > rhauch@gmail.com>
> > > > > > > > > > > > > > > wrote:
> > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > >> > > Hi, Yash.
> > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > >> > > I'm not sure I quite understand why it
> > would
> > > > be
> > > > > > > > "easier"
> > > > > > > > > > for
> > > > > > > > > > > > > > > connector
> > > > > > > > > > > > > > > >> > > > developers to account for implementing
> > two
> > > > > > > different
> > > > > > > > > > > > > overloaded
> > > > > > > > > > > > > > > >> `put`
> > > > > > > > > > > > > > > >> > > > methods (assuming that they want to
> use
> > > this
> > > > > new
> > > > > > > > > > feature)
> > > > > > > > > > > > > versus
> > > > > > > > > > > > > > > >> using
> > > > > > > > > > > > > > > >> > a
> > > > > > > > > > > > > > > >> > > > try-catch block around `SinkRecord`
> > access
> > > > > > > methods?
> > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > >> > > Using a try-catch to try around an API
> > > method
> > > > > that
> > > > > > > > > *might*
> > > > > > > > > > > be
> > > > > > > > > > > > > > there
> > > > > > > > > > > > > > > >> is a
> > > > > > > > > > > > > > > >> > > very unusual thing for most developers.
> > > > > > > Unfortunately,
> > > > > > > > > > we've
> > > > > > > > > > > > had
> > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > >> > resort
> > > > > > > > > > > > > > > >> > > to this atypical approach with Connect
> in
> > > > places
> > > > > > > when
> > > > > > > > > > there
> > > > > > > > > > > > was
> > > > > > > > > > > > > no
> > > > > > > > > > > > > > > >> good
> > > > > > > > > > > > > > > >> > > alternative. We seem to relying upon
> > pattern
> > > > > > because
> > > > > > > > > it's
> > > > > > > > > > > > easier
> > > > > > > > > > > > > > for
> > > > > > > > > > > > > > > >> us,
> > > > > > > > > > > > > > > >> > > not because it offers a better
> experience
> > > for
> > > > > > > > Connector
> > > > > > > > > > > > > > developers.
> > > > > > > > > > > > > > > >> IMO,
> > > > > > > > > > > > > > > >> > if
> > > > > > > > > > > > > > > >> > > there's a practical alternative that
> uses
> > > > normal
> > > > > > > > > > development
> > > > > > > > > > > > > > > practices
> > > > > > > > > > > > > > > >> > and
> > > > > > > > > > > > > > > >> > > techniques, then we should use that
> > > > alternative.
> > > > > > > IIUC,
> > > > > > > > > > there
> > > > > > > > > > > > is
> > > > > > > > > > > > > at
> > > > > > > > > > > > > > > >> least
> > > > > > > > > > > > > > > >> > > one practical alternative for this KIP
> > that
> > > > > would
> > > > > > > not
> > > > > > > > > > > require
> > > > > > > > > > > > > > > >> developers
> > > > > > > > > > > > > > > >> > to
> > > > > > > > > > > > > > > >> > > use the unusual try-catch to handle the
> > case
> > > > > where
> > > > > > > > > methods
> > > > > > > > > > > are
> > > > > > > > > > > > > not
> > > > > > > > > > > > > > > >> found.
> > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > >> > > I also think having two `put` methods is
> > > > easier
> > > > > > when
> > > > > > > > the
> > > > > > > > > > > > > Connector
> > > > > > > > > > > > > > > >> has to
> > > > > > > > > > > > > > > >> > > do different things for different
> Connect
> > > > > > runtimes,
> > > > > > > > too.
> > > > > > > > > > One
> > > > > > > > > > > > of
> > > > > > > > > > > > > > > those
> > > > > > > > > > > > > > > >> > > methods is called by newer Connect
> > runtimes
> > > > with
> > > > > > the
> > > > > > > > new
> > > > > > > > > > > > > behavior,
> > > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > >> > the
> > > > > > > > > > > > > > > >> > > other method is called by an older
> Connect
> > > > > > runtime.
> > > > > > > Of
> > > > > > > > > > > course,
> > > > > > > > > > > > > if
> > > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > >> > > developer does not need separate
> methods,
> > > they
> > > > > can
> > > > > > > > > easily
> > > > > > > > > > > have
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > >> older
> > > > > > > > > > > > > > > >> > > `put` method simply delegate to the
> newer
> > > > > method.
> > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > >> > > Finally, this gives us a roadmap for
> > > > > *eventually*
> > > > > > > > > > > deprecating
> > > > > > > > > > > > > the
> > > > > > > > > > > > > > > >> older
> > > > > > > > > > > > > > > >> > > method, once the Connect runtime
> versions
> > > > > without
> > > > > > > this
> > > > > > > > > > > change
> > > > > > > > > > > > > are
> > > > > > > > > > > > > > > old
> > > > > > > > > > > > > > > >> > > enough.
> > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > >> > > I think the advantage of going with the
> > > > > > > > > > > > > > > >> > > > proposed approach in the KIP is that
> it
> > > > > wouldn't
> > > > > > > > > require
> > > > > > > > > > > > extra
> > > > > > > > > > > > > > > >> > > book-keeping
> > > > > > > > > > > > > > > >> > > > (the Map<SinkRecord,
> > > > > > > > > > > > > > > >> > > > TopicPartition> in `WorkerSinkTask` in
> > > your
> > > > > > > proposed
> > > > > > > > > > > > approach)
> > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > >> > > The connector does have to do some of
> this
> > > > > > > bookkeeping
> > > > > > > > > in
> > > > > > > > > > > how
> > > > > > > > > > > > > they
> > > > > > > > > > > > > > > >> track
> > > > > > > > > > > > > > > >> > > the topic partition offsets used in the
> > > > > > `preCommit`,
> > > > > > > > and
> > > > > > > > > > the
> > > > > > > > > > > > > > > >> pre-commit
> > > > > > > > > > > > > > > >> > > methods use the same
> `Map<TopicPartition,
> > > > > > > > > > OffsetAndMetadata>
> > > > > > > > > > > > > > > >> > > currentOffsets`
> > > > > > > > > > > > > > > >> > > data structure I'm suggesting be used.
> > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > >> > > I hope that helps.
> > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > >> > > Best regards,
> > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > >> > > Randall
> > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > >> > > On Mon, Sep 26, 2022 at 9:38 AM Yash
> > Mayya <
> > > > > > > > > > > > > yash.mayya@gmail.com>
> > > > > > > > > > > > > > > >> wrote:
> > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > >> > > > Hi Randall,
> > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > >> > > > Thanks for reviewing the KIP!
> > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > >> > > > > That latter logic can get quite
> ugly.
> > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > >> > > > I'm not sure I quite understand why it
> > > would
> > > > > be
> > > > > > > > > "easier"
> > > > > > > > > > > for
> > > > > > > > > > > > > > > >> connector
> > > > > > > > > > > > > > > >> > > > developers to account for implementing
> > two
> > > > > > > different
> > > > > > > > > > > > > overloaded
> > > > > > > > > > > > > > > >> `put`
> > > > > > > > > > > > > > > >> > > > methods (assuming that they want to
> use
> > > this
> > > > > new
> > > > > > > > > > feature)
> > > > > > > > > > > > > versus
> > > > > > > > > > > > > > > >> using
> > > > > > > > > > > > > > > >> > a
> > > > > > > > > > > > > > > >> > > > try-catch block around `SinkRecord`
> > access
> > > > > > > methods?
> > > > > > > > In
> > > > > > > > > > > both
> > > > > > > > > > > > > > > cases, a
> > > > > > > > > > > > > > > >> > > > connector developer would need to
> write
> > > > > > additional
> > > > > > > > > code
> > > > > > > > > > in
> > > > > > > > > > > > > order
> > > > > > > > > > > > > > > to
> > > > > > > > > > > > > > > >> > > ensure
> > > > > > > > > > > > > > > >> > > > that their connector continues working
> > > with
> > > > > > older
> > > > > > > > > > Connect
> > > > > > > > > > > > > > > runtimes.
> > > > > > > > > > > > > > > >> > > > Furthermore, we would probably need to
> > > > > carefully
> > > > > > > > > > document
> > > > > > > > > > > > how
> > > > > > > > > > > > > > the
> > > > > > > > > > > > > > > >> > > > implementation for the older `put`
> > method
> > > > > should
> > > > > > > > look
> > > > > > > > > > like
> > > > > > > > > > > > for
> > > > > > > > > > > > > > > >> > connectors
> > > > > > > > > > > > > > > >> > > > that want to use this new feature. I
> > think
> > > > the
> > > > > > > > > advantage
> > > > > > > > > > > of
> > > > > > > > > > > > > > going
> > > > > > > > > > > > > > > >> with
> > > > > > > > > > > > > > > >> > > the
> > > > > > > > > > > > > > > >> > > > proposed approach in the KIP is that
> it
> > > > > wouldn't
> > > > > > > > > require
> > > > > > > > > > > > extra
> > > > > > > > > > > > > > > >> > > book-keeping
> > > > > > > > > > > > > > > >> > > > (the Map<SinkRecord,
> > > > > > > > > > > > > > > >> > > > TopicPartition> in `WorkerSinkTask` in
> > > your
> > > > > > > proposed
> > > > > > > > > > > > approach)
> > > > > > > > > > > > > > and
> > > > > > > > > > > > > > > >> also
> > > > > > > > > > > > > > > >> > > the
> > > > > > > > > > > > > > > >> > > > fact that the try-catch based logic is
> > an
> > > > > > already
> > > > > > > > > > > > established
> > > > > > > > > > > > > > > >> pattern
> > > > > > > > > > > > > > > >> > > > through
> > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://cwiki.apache.org/confluence/display/KAFKA/KIP-610%3A+Error+Reporting+in+Sink+Connectors
> > > > > > > > > > > > > > > >> > > > and other KIPs which added methods to
> > > > > > source/sink
> > > > > > > > > > > > > connector/task
> > > > > > > > > > > > > > > >> > > contexts.
> > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > >> > > > Let me know if you still feel that
> > having
> > > a
> > > > > new
> > > > > > > > > > overloaded
> > > > > > > > > > > > put
> > > > > > > > > > > > > > > >> method
> > > > > > > > > > > > > > > >> > is
> > > > > > > > > > > > > > > >> > > a
> > > > > > > > > > > > > > > >> > > > cleaner solution and I'd be happy to
> > > > > reconsider!
> > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > >> > > > Thanks,
> > > > > > > > > > > > > > > >> > > > Yash
> > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > >> > > > On Thu, Sep 22, 2022 at 11:18 PM
> Randall
> > > > > Hauch <
> > > > > > > > > > > > > > rhauch@gmail.com>
> > > > > > > > > > > > > > > >> > wrote:
> > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > >> > > > > Hi, Yash. Thanks for picking up this
> > KIP
> > > > and
> > > > > > > > > > discussion.
> > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > >> > > > > The KIP includes this rejected
> > > > alternative:
> > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > >> > > > > > 4. Update SinkTask.put in any way
> to
> > > > pass
> > > > > > the
> > > > > > > > new
> > > > > > > > > > > > > > information
> > > > > > > > > > > > > > > >> > outside
> > > > > > > > > > > > > > > >> > > > > > SinkRecord (e.g. a Map or a
> derived
> > > > class)
> > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > >> > > > > >    -
> > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > >> > > > > >    Much more disruptive change
> > without
> > > > > > > > > considerable
> > > > > > > > > > > pros
> > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > >> > > > > One advantage about doing this is
> that
> > > > sink
> > > > > > > > > connector
> > > > > > > > > > > > > > > >> implementations
> > > > > > > > > > > > > > > >> > > can
> > > > > > > > > > > > > > > >> > > > > more easily implement two different
> > > > > "put(...)"
> > > > > > > > > methods
> > > > > > > > > > > to
> > > > > > > > > > > > > > handle
> > > > > > > > > > > > > > > >> > > running
> > > > > > > > > > > > > > > >> > > > in
> > > > > > > > > > > > > > > >> > > > > a variety of runtimes, without
> having
> > to
> > > > use
> > > > > > > > > try-catch
> > > > > > > > > > > > logic
> > > > > > > > > > > > > > > >> around
> > > > > > > > > > > > > > > >> > the
> > > > > > > > > > > > > > > >> > > > > newer SinkRecord access methods.
> That
> > > > latter
> > > > > > > logic
> > > > > > > > > can
> > > > > > > > > > > get
> > > > > > > > > > > > > > quite
> > > > > > > > > > > > > > > >> > ugly.
> > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > >> > > > > For example, the existing `put`
> method
> > > has
> > > > > > this
> > > > > > > > > > > signature:
> > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > >> > > > > public abstract void
> > > > > > put(Collection<SinkRecord>
> > > > > > > > > > > records);
> > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > >> > > > > If we added an overloaded method
> that
> > > > passed
> > > > > > in
> > > > > > > a
> > > > > > > > > map
> > > > > > > > > > of
> > > > > > > > > > > > the
> > > > > > > > > > > > > > old
> > > > > > > > > > > > > > > >> > > > > topic+partition for each record (and
> > > > defined
> > > > > > the
> > > > > > > > > > absence
> > > > > > > > > > > > of
> > > > > > > > > > > > > an
> > > > > > > > > > > > > > > >> entry
> > > > > > > > > > > > > > > >> > as
> > > > > > > > > > > > > > > >> > > > > having an unchanged topic and
> > > partition):
> > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > >> > > > > public void
> put(Collection<SinkRecord>
> > > > > > records,
> > > > > > > > > > > > > > Map<SinkRecord,
> > > > > > > > > > > > > > > >> > > > > TopicPartition>
> > updatedTopicPartitions)
> > > {
> > > > > > > > > > > > > > > >> > > > > put(records);
> > > > > > > > > > > > > > > >> > > > > }
> > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > >> > > > > then a `SinkTask` implementation
> that
> > > > wants
> > > > > to
> > > > > > > use
> > > > > > > > > > this
> > > > > > > > > > > > new
> > > > > > > > > > > > > > > >> feature
> > > > > > > > > > > > > > > >> > > could
> > > > > > > > > > > > > > > >> > > > > simply implement both methods:
> > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > >> > > > > public void
> put(Collection<SinkRecord>
> > > > > > records)
> > > > > > > {
> > > > > > > > > > > > > > > >> > > > > // Running in an older runtime, so
> no
> > > > > tracking
> > > > > > > of
> > > > > > > > > > > > > SMT-modified
> > > > > > > > > > > > > > > >> topic
> > > > > > > > > > > > > > > >> > > > names
> > > > > > > > > > > > > > > >> > > > > or partitions
> > > > > > > > > > > > > > > >> > > > > put(records, Map.of());
> > > > > > > > > > > > > > > >> > > > > }
> > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > >> > > > > public void
> put(Collection<SinkRecord>
> > > > > > records,
> > > > > > > > > > > > > > Map<SinkRecord,
> > > > > > > > > > > > > > > >> > > > > TopicPartition>
> > updatedTopicPartitions)
> > > {
> > > > > > > > > > > > > > > >> > > > > // real logic here
> > > > > > > > > > > > > > > >> > > > > }
> > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > >> > > > > This seems a lot easier than having
> to
> > > use
> > > > > > > > try-catch
> > > > > > > > > > > > logic,
> > > > > > > > > > > > > > yet
> > > > > > > > > > > > > > > >> still
> > > > > > > > > > > > > > > >> > > > > allows sink connectors to utilize
> the
> > > new
> > > > > > > > > > functionality
> > > > > > > > > > > > and
> > > > > > > > > > > > > > > still
> > > > > > > > > > > > > > > >> > work
> > > > > > > > > > > > > > > >> > > > with
> > > > > > > > > > > > > > > >> > > > > older Connect runtimes.
> > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > >> > > > > WDYT?
> > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > >> > > > > Randall
> > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > >> > > > > On Thu, Sep 8, 2022 at 7:03 AM Yash
> > > Mayya
> > > > <
> > > > > > > > > > > > > > yash.mayya@gmail.com
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > > >> > > wrote:
> > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > >> > > > > > Hi all,
> > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > >> > > > > > I would like to (re)start a new
> > > > discussion
> > > > > > > > thread
> > > > > > > > > on
> > > > > > > > > > > > > KIP-793
> > > > > > > > > > > > > > > >> (Kafka
> > > > > > > > > > > > > > > >> > > > > > Connect) which proposes some
> > additions
> > > > to
> > > > > > the
> > > > > > > > > public
> > > > > > > > > > > > > > > SinkRecord
> > > > > > > > > > > > > > > >> > > > interface
> > > > > > > > > > > > > > > >> > > > > > in order to support topic mutating
> > > SMTs
> > > > > for
> > > > > > > sink
> > > > > > > > > > > > > connectors
> > > > > > > > > > > > > > > >> that do
> > > > > > > > > > > > > > > >> > > > their
> > > > > > > > > > > > > > > >> > > > > > own offset tracking.
> > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > >> > > > > > Links:
> > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > >> > > > > > KIP:
> > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=191336830
> > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > >> > > > > > Older discussion thread:
> > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > >>
> > > > > > > > > > >
> > > > > https://lists.apache.org/thread/00kcth6057jdcsyzgy1x8nb2s1cymy8h
> > > > > > ,
> > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > >>
> > > > > > > > > > >
> > > > > https://lists.apache.org/thread/rzqkm0q5y5v3vdjhg8wqppxbkw7nyopj
> > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > >> > > > > > Jira:
> > > > > > > > > > > https://issues.apache.org/jira/browse/KAFKA-13431
> > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > >> > > > > > Thanks,
> > > > > > > > > > > > > > > >> > > > > > Yash
> > > > > > > > > > > > > > > >> > > > > >
> > > > > > > > > > > > > > > >> > > > >
> > > > > > > > > > > > > > > >> > > >
> > > > > > > > > > > > > > > >> > >
> > > > > > > > > > > > > > > >> >
> > > > > > > > > > > > > > > >>
> > > > > > > > > > > > > > > >
> > > > > > > > > > > > > > >
> > > > > > > > > > > > > >
> > > > > > > > > > > > >
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
>