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https://issues.apache.org/jira/browse/KAFKA-1510?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14092205#comment-14092205
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Jun Rao commented on KAFKA-1510:
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Thinking about this a bit more, would it be more reliable to do the expiration
of an offset based on the last connect time from the client, instead of the
last time the offset is modified? In the new consumer, we will be tracking the
set of consumers per consumer group on the broker. We can expire an offset if
the time since the last time the partition was actively owned by a consumer
exceeds the threshold. Handling consumer coordinator failover can be a bit
tricky. We can probably just start doing the expiration countdown from the
beginning during the failover. This means that the removal of some of the
offsets may be delayed. This maybe ok since the consumer coordinator failover
should be rare.
> Force offset commits when migrating consumer offsets from zookeeper to kafka
> ----------------------------------------------------------------------------
>
> Key: KAFKA-1510
> URL: https://issues.apache.org/jira/browse/KAFKA-1510
> Project: Kafka
> Issue Type: Bug
> Affects Versions: 0.8.2
> Reporter: Joel Koshy
> Assignee: Joel Koshy
> Labels: newbie
> Fix For: 0.8.2
>
> Attachments: kafka-1510.patch
>
>
> When migrating consumer offsets from ZooKeeper to kafka, we have to turn on
> dual-commit (i.e., the consumers will commit offsets to both zookeeper and
> kafka) in addition to setting offsets.storage to kafka. However, when we
> commit offsets we only commit offsets if they have changed (since the last
> commit). For low-volume topics or for topics that receive data in bursts
> offsets may not move for a long period of time. Therefore we may want to
> force the commit (even if offsets have not changed) when migrating (i.e.,
> when dual-commit is enabled) - we can add a minimum interval threshold (say
> force commit after every 10 auto-commits) as well as on rebalance and
> shutdown.
> Also, I think it is safe to switch the default for offsets.storage from
> zookeeper to kafka and set the default to dual-commit (for people who have
> not migrated yet). We have deployed this to the largest consumers at linkedin
> and have not seen any issues so far (except for the migration caveat that
> this jira will resolve).
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