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https://issues.apache.org/jira/browse/KAFKA-3806?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16253743#comment-16253743
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John Crowley commented on KAFKA-3806:
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Thanks for quick response. Yes, I did find the 4682 entry & KIP and also posted
there. It does look like they are trying to clean up a lot of the consumer-side
issues.
And there are workarounds proposed, just thought it cleaner overall if you
could just set offsets.retention.minutes on the groupId once, and not need to
worry that every piece of code touching this groupId has to be checked that it
is passing the correct expiration. Also would make it clear to any Kafka DevOps
that this groupId is being handled specially.
In a general case, would be nice if every broker property could be overwritten
on a per topic or per groupId basis - if it could reasonably apply to a
specific topic or groupId. E.g. offsets.load.buffer.size deals only with how
the broker is operating, but retention.ms can logically differ between
different topics, and offsets.retention.minutes might well differ for different
groupIds - based on the use-case which applies to a particular topic or group.
> Adjust default values of log.retention.hours and offsets.retention.minutes
> --------------------------------------------------------------------------
>
> Key: KAFKA-3806
> URL: https://issues.apache.org/jira/browse/KAFKA-3806
> Project: Kafka
> Issue Type: Improvement
> Components: config
> Affects Versions: 0.9.0.1, 0.10.0.0
> Reporter: Michal Turek
> Priority: Minor
> Fix For: 1.1.0
>
>
> Combination of default values of log.retention.hours (168 hours = 7 days) and
> offsets.retention.minutes (1440 minutes = 1 day) may be dangerous in special
> cases. Offset retention should be always greater than log retention.
> We have observed the following scenario and issue:
> - Producing of data to a topic was disabled two days ago by producer update,
> topic wasn't deleted.
> - Consumer consumed all data and properly committed offsets to Kafka.
> - Consumer made no more offset commits for that topic because there was no
> more incoming data and there was nothing to confirm. (We have auto-commit
> disabled, I'm not sure how behaves enabled auto-commit.)
> - After one day: Kafka cleared too old offsets according to
> offsets.retention.minutes.
> - After two days: Long-term running consumer was restarted after update, it
> didn't find any committed offsets for that topic since they were deleted by
> offsets.retention.minutes so it started consuming from the beginning.
> - The messages were still in Kafka due to larger log.retention.hours, about 5
> days of messages were read again.
> Known workaround to solve this issue:
> - Explicitly configure log.retention.hours and offsets.retention.minutes,
> don't use defaults.
> Proposals:
> - Prolong default value of offsets.retention.minutes to be at least twice
> larger than log.retention.hours.
> - Check these values during Kafka startup and log a warning if
> offsets.retention.minutes is smaller than log.retention.hours.
> - Add a note to migration guide about differences between storing of offsets
> in ZooKeeper and Kafka (http://kafka.apache.org/documentation.html#upgrade).
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