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https://issues.apache.org/jira/browse/KAFKA-14196?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17600552#comment-17600552
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Philip Nee commented on KAFKA-14196:
------------------------------------
Kind of originated from this commit:
https://github.com/apache/kafka/pull/12349/files
> Duplicated consumption during rebalance, causing OffsetValidationTest to act
> flaky
> ----------------------------------------------------------------------------------
>
> Key: KAFKA-14196
> URL: https://issues.apache.org/jira/browse/KAFKA-14196
> Project: Kafka
> Issue Type: Bug
> Components: clients, consumer
> Affects Versions: 3.3.0, 3.2.1
> Reporter: Philip Nee
> Assignee: Philip Nee
> Priority: Major
> Labels: new-consumer-threading-should-fix
>
> Several flaky tests under OffsetValidationTest are indicating potential
> consumer duplication issue, when autocommit is enabled. I believe this is
> affecting *3.2* and onward. Below shows the failure message:
>
> {code:java}
> Total consumed records 3366 did not match consumed position 3331 {code}
>
> After investigating the log, I discovered that the data consumed between the
> start of a rebalance event and the async commit was lost for those failing
> tests. In the example below, the rebalance event kicks in at around
> 1662054846995 (first record), and the async commit of the offset 3739 is
> completed at around 1662054847015 (right before partitions_revoked).
>
> {code:java}
> {"timestamp":1662054846995,"name":"records_consumed","count":3,"partitions":[{"topic":"test_topic","partition":0,"count":3,"minOffset":3739,"maxOffset":3741}]}
> {"timestamp":1662054846998,"name":"records_consumed","count":2,"partitions":[{"topic":"test_topic","partition":0,"count":2,"minOffset":3742,"maxOffset":3743}]}
> {"timestamp":1662054847008,"name":"records_consumed","count":2,"partitions":[{"topic":"test_topic","partition":0,"count":2,"minOffset":3744,"maxOffset":3745}]}
> {"timestamp":1662054847016,"name":"partitions_revoked","partitions":[{"topic":"test_topic","partition":0}]}
> {"timestamp":1662054847031,"name":"partitions_assigned","partitions":[{"topic":"test_topic","partition":0}]}
> {"timestamp":1662054847038,"name":"records_consumed","count":23,"partitions":[{"topic":"test_topic","partition":0,"count":23,"minOffset":3739,"maxOffset":3761}]}
> {code}
> A few things to note here:
> # Manually calling commitSync in the onPartitionsRevoke cb seems to
> alleviate the issue
> # Setting includeMetadataInTimeout to false also seems to alleviate the
> issue.
> The above tries seems to suggest that contract between poll() and
> asyncCommit() is broken. AFAIK, we implicitly uses poll() to ack the
> previously fetched data, and the consumer would (try to) commit these offsets
> in the current poll() loop. However, it seems like as the poll continues to
> loop, the "acked" data isn't being committed.
>
> I believe this could be introduced in KAFKA-14024, which originated from
> KAFKA-13310.
> More specifically, (see the comments below), the ConsumerCoordinator will
> alway return before async commit, due to the previous incomplete commit.
> However, this is a bit contradictory here because:
> # I think we want to commit asynchronously while the poll continues, and if
> we do that, we are back to KAFKA-14024, that the consumer will get rebalance
> timeout and get kicked out of the group.
> # But we also need to commit all the "acked" offsets before revoking the
> partition, and this has to be blocked.
> *Steps to Reproduce the Issue:*
> # Check out AK 3.2
> # Run this several times: (Recommend to only run runs with autocommit
> enabled in consumer_test.py to save time)
> {code:java}
> _DUCKTAPE_OPTIONS="--debug"
> TC_PATHS="tests/kafkatest/tests/client/consumer_test.py::OffsetValidationTest.test_consumer_failure"
> bash tests/docker/run_tests.sh {code}
>
> *Steps to Diagnose the Issue:*
> # Open the test results in *results/*
> # Go to the consumer log. It might look like this
>
> {code:java}
> results/2022-09-03--005/OffsetValidationTest/test_consumer_failure/clean_shutdown=True.enable_autocommit=True.metadata_quorum=ZK/2/VerifiableConsumer-0-xxxxxxxxxx/dockerYY
> {code}
> 3. Find the docker instance that has partition getting revoked and rejoined.
> Observed the offset before and after.
> *Propose Fixes:*
> TBD
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