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https://issues.apache.org/jira/browse/KAFKA-20449?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Ken Huang updated KAFKA-20449:
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Fix Version/s: 4.3.2
> OffsetFetcherUtils.updateSubscriptionState logs at WARN for benign race
> condition during rebalance
> --------------------------------------------------------------------------------------------------
>
> Key: KAFKA-20449
> URL: https://issues.apache.org/jira/browse/KAFKA-20449
> Project: Kafka
> Issue Type: Bug
> Components: clients, consumer
> Affects Versions: 4.3.0, 4.1.2, 4.2.1
> Reporter: Tamas Kornai
> Assignee: Tamas Kornai
> Priority: Major
> Fix For: 4.4.0, 4.3.2
>
>
> KAFKA-20131 introduced a log.warn() in
> OffsetFetcherUtils.updateSubscriptionState() for the case where a
> LIST_OFFSETS response arrives after the partition has already been revoked:
> {code:java}
> log.warn("Not updating high watermark for partition {} as it is no longer
> assigned", partition);
> {code}
> This is a benign race condition that naturally occurs during consumer group
> rebalances — a LIST_OFFSETS request is issued, the partition gets revoked
> before the response returns, and the response is simply
> discarded. No data loss or correctness issue arises.
> However, the WARN level is problematic in practice. Many organizations use
> warning log rates as a signal for canary release health. Since rebalances are
> frequent during rolling deployments, canary instances
> generate a high volume of these warnings, which triggers automated rollback
> of otherwise healthy releases.
> The log should be downgraded to DEBUG (or at most INFO), since it describes
> expected, harmless behavior that requires no operator action.
> Affected code:
> clients/src/main/java/org/apache/kafka/clients/consumer/internals/OffsetFetcherUtils.java,
> lines 281-285 (introduced in commit abcbef6a4c, PR #21457).
> Both log statements are affected:
> - "Not updating high watermark for partition {} as it is no longer assigned"
> (READ_UNCOMMITTED)
> - "Not updating last stable offset for partition {} as it is no longer
> assigned" (READ_COMMITTED)
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