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https://issues.apache.org/jira/browse/KAFKA-2674?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14965803#comment-14965803
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Jason Gustafson commented on KAFKA-2674:
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[~becket_qin] I think the only problem with that is that some users might be
doing their own offset management, in which case they might not even be using
Kafka to store offsets. Currently, we only commit on close if auto-commit is
enabled. I guess we could also depend on the user to manually do commits prior
to close, but it seems like they'd probably already have their commit logic in
the revoke callback. What do you think?
> ConsumerRebalanceListener.onPartitionsRevoked() is not called on consumer
> close
> -------------------------------------------------------------------------------
>
> Key: KAFKA-2674
> URL: https://issues.apache.org/jira/browse/KAFKA-2674
> Project: Kafka
> Issue Type: Bug
> Components: consumer
> Affects Versions: 0.9.0.0
> Reporter: Michal Turek
> Assignee: Neha Narkhede
>
> Hi, I'm investigating and testing behavior of new consumer from the planned
> release 0.9 and found an inconsistency in calling of rebalance callbacks.
> I noticed that ConsumerRebalanceListener.onPartitionsRevoked() is NOT called
> during consumer close and application shutdown. It's JavaDoc contract says:
> - "This method will be called before a rebalance operation starts and after
> the consumer stops fetching data."
> - "It is recommended that offsets should be committed in this callback to
> either Kafka or a custom offset store to prevent duplicate data."
> I believe calling consumer.close() is a start of rebalance operation and even
> the local consumer that is actually closing should be notified to be able to
> process any rebalance logic including offsets commit (e.g. if auto-commit is
> disabled).
> There are commented logs of current and expected behaviors.
> {noformat}
> // Application start
> 2015-10-20 15:14:02.208 INFO o.a.k.common.utils.AppInfoParser
> [TestConsumer-worker-0]: Kafka version : 0.9.0.0-SNAPSHOT
> (AppInfoParser.java:82)
> 2015-10-20 15:14:02.208 INFO o.a.k.common.utils.AppInfoParser
> [TestConsumer-worker-0]: Kafka commitId : 241b9ab58dcbde0c
> (AppInfoParser.java:83)
> // Consumer started (the first one in group), rebalance callbacks are called
> including empty onPartitionsRevoked()
> 2015-10-20 15:14:02.333 INFO c.a.e.kafka.newapi.TestConsumer
> [TestConsumer-worker-0]: Rebalance callback, revoked: []
> (TestConsumer.java:95)
> 2015-10-20 15:14:02.343 INFO c.a.e.kafka.newapi.TestConsumer
> [TestConsumer-worker-0]: Rebalance callback, assigned: [testB-1, testA-0,
> testB-0, testB-3, testA-2, testB-2, testA-1, testA-4, testB-4, testA-3]
> (TestConsumer.java:100)
> // Another consumer joined the group, rebalancing
> 2015-10-20 15:14:17.345 INFO o.a.k.c.c.internals.Coordinator
> [TestConsumer-worker-0]: Attempt to heart beat failed since the group is
> rebalancing, try to re-join group. (Coordinator.java:714)
> 2015-10-20 15:14:17.346 INFO c.a.e.kafka.newapi.TestConsumer
> [TestConsumer-worker-0]: Rebalance callback, revoked: [testB-1, testA-0,
> testB-0, testB-3, testA-2, testB-2, testA-1, testA-4, testB-4, testA-3]
> (TestConsumer.java:95)
> 2015-10-20 15:14:17.349 INFO c.a.e.kafka.newapi.TestConsumer
> [TestConsumer-worker-0]: Rebalance callback, assigned: [testB-3, testA-4,
> testB-4, testA-3] (TestConsumer.java:100)
> // Consumer started closing, there SHOULD be onPartitionsRevoked() callback
> to commit offsets like during standard rebalance, but it is missing
> 2015-10-20 15:14:39.280 INFO c.a.e.kafka.newapi.TestConsumer [main]:
> Closing instance (TestConsumer.java:42)
> 2015-10-20 15:14:40.264 INFO c.a.e.kafka.newapi.TestConsumer
> [TestConsumer-worker-0]: Worker thread stopped (TestConsumer.java:89)
> {noformat}
> Workaround is to call onPartitionsRevoked() explicitly and manually just
> before calling consumer.close() but it seems dirty and error prone for me. It
> can be simply forgotten be someone without such experience.
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