You are viewing a plain text version of this content. The canonical link for it is here.
Posted to commits@cassandra.apache.org by "Avraham Kalvo (JIRA)" <ji...@apache.org> on 2019/01/10 14:10:00 UTC
[jira] [Comment Edited] (CASSANDRA-14957) Rolling Restart Of Nodes
Causes Dataloss Due To Schema Collision
[ https://issues.apache.org/jira/browse/CASSANDRA-14957?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16739427#comment-16739427 ]
Avraham Kalvo edited comment on CASSANDRA-14957 at 1/10/19 2:09 PM:
--------------------------------------------------------------------
To be clear, here's the timeline of the incident:
```
12:05:02 first node state jump to shutdown for restart
12:06:37 INFO Initializing tasks_scheduler_external.tasks (first node)
12:06:39 WARN UnknownColumnFamilyException reading from socket; closing (first node)
...
12:09:15 only trace of service migration running by issuing the following:
`CREATE KEYSPACE IF NOT EXISTS tasks_scheduler_external WITH replication =
{'class': 'SimpleStrategy', 'replication_factor': '3'};`
...
12:09:31 last node started after restart
```
Notice *no tables* were attempted to be created throughout the restart, and also the keyspace wasn't recreated as it was already in existence.
Hence - the new version of the table, as visible in the file system, *has nothing to do* with any explicit DDL running before, throughout and after the rolling restart.
The schema (DDL) hasn't changed - just the data was split into a new version on the filesystem which eventually became the version the cluster agrees on once it has completed its rolling restart.
Thank you.
Avi.
was (Author: via.vokal):
To be clear, here's the timeline of the incident:
12:05:02 first node state jump to shutdown for restart
12:06:37 INFO Initializing tasks_scheduler_external.tasks (first node)
12:06:39 WARN UnknownColumnFamilyException reading from socket; closing (first node)
...
12:09:15 only trace of service migration running by issuing the following:
`CREATE KEYSPACE IF NOT EXISTS tasks_scheduler_external WITH replication =
{'class': 'SimpleStrategy', 'replication_factor': '3'};`
...
12:09:31 last node started after restart
Notice *no tables* were attempted to be created throughout the restart, and also the keyspace wasn't recreated as it was already in existence.
Hence - the new version of the table, as visible in the file system, *has nothing to do* with any explicit DDL running before, throughout and after the rolling restart.
The schema (DDL) hasn't changed - just the data was split into a new version on the filesystem which eventually became the version the cluster agrees on once it has completed its rolling restart.
Thank you.
Avi.
> Rolling Restart Of Nodes Causes Dataloss Due To Schema Collision
> ----------------------------------------------------------------
>
> Key: CASSANDRA-14957
> URL: https://issues.apache.org/jira/browse/CASSANDRA-14957
> Project: Cassandra
> Issue Type: Bug
> Components: Cluster/Schema
> Reporter: Avraham Kalvo
> Priority: Major
>
> We were issuing a rolling restart on a mission-critical five node C* cluster.
> The first node which was restarted got the following messages in its system.log:
> ```
> January 2nd 2019, 12:06:37.310 - INFO 12:06:35 Initializing tasks_scheduler_external.tasks
> ```
> ```
> WARN 12:06:39 UnknownColumnFamilyException reading from socket; closing
> org.apache.cassandra.db.UnknownColumnFamilyException: Couldn't find table for cfId bd7200a0-1567-11e8-8974-855d74ee356f. If a table was just created, this is likely due to the schema not being fully propagated. Please wait for schema agreement on table creation.
> at org.apache.cassandra.config.CFMetaData$Serializer.deserialize(CFMetaData.java:1336) ~[apache-cassandra-3.0.10.jar:3.0.10]
> at org.apache.cassandra.db.partitions.PartitionUpdate$PartitionUpdateSerializer.deserialize30(PartitionUpdate.java:660) ~[apache-cassandra-3.0.10.jar:3.0.10]
> at org.apache.cassandra.db.partitions.PartitionUpdate$PartitionUpdateSerializer.deserialize(PartitionUpdate.java:635) ~[apache-cassandra-3.0.10.jar:3.0.10]
> at org.apache.cassandra.db.Mutation$MutationSerializer.deserialize(Mutation.java:330) ~[apache-cassandra-3.0.10.jar:3.0.10]
> at org.apache.cassandra.db.Mutation$MutationSerializer.deserialize(Mutation.java:349) ~[apache-cassandra-3.0.10.jar:3.0.10]
> at org.apache.cassandra.db.Mutation$MutationSerializer.deserialize(Mutation.java:286) ~[apache-cassandra-3.0.10.jar:3.0.10]
> at org.apache.cassandra.net.MessageIn.read(MessageIn.java:98) ~[apache-cassandra-3.0.10.jar:3.0.10]
> at org.apache.cassandra.net.IncomingTcpConnection.receiveMessage(IncomingTcpConnection.java:201) ~[apache-cassandra-3.0.10.jar:3.0.10]
> at org.apache.cassandra.net.IncomingTcpConnection.receiveMessages(IncomingTcpConnection.java:178) ~[apache-cassandra-3.0.10.jar:3.0.10]
> at org.apache.cassandra.net.IncomingTcpConnection.run(IncomingTcpConnection.java:92) ~[apache-cassandra-3.0.10.jar:3.0.10]
> ```
> The latter was then repeated several times across the cluster.
> It was then found out that the table in question `tasks_scheduler_external.tasks` was created with a new schema version sometime along the entire cluster consecutive restart and became available once the schema agreement settled, which started taking requests leaving the previous version of the schema unavailable for any request, thus generating a data loss to our online system.
> Data loss was recovered by manually copying SSTables from the previous version directory of the schema to the new one followed by `nodetool refresh` to the relevant table.
> The above has repeated itself for several tables across various keyspaces.
> One other thing to mention is that a repair was in place for the first node to be restarted, which was obviously stopped as the daemon was shut down, but this doesn't seem to do with the above at first glance.
> Seems somewhat related to:
> https://issues.apache.org/jira/browse/CASSANDRA-13559
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
---------------------------------------------------------------------
To unsubscribe, e-mail: commits-unsubscribe@cassandra.apache.org
For additional commands, e-mail: commits-help@cassandra.apache.org