[
https://issues.apache.org/jira/browse/KAFKA-10643?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17412623#comment-17412623
]
Maatari commented on KAFKA-10643:
---------------------------------
[~gray.john] It feels like disabling it altogether might make sense then. Not
sure, but it seems most kafka stream application have rather static input
inputs, the rest can be rediscovered trough the normal flow of request which
always fetch the metadata. So if your input never changes, during the life time
of your application why bother. If the input change, feels like it would a
completely different app, with different task assignment and what not ... So
not sure it is not a bug
> Static membership - repetitive PreparingRebalance with updating metadata for
> member reason
> ------------------------------------------------------------------------------------------
>
> Key: KAFKA-10643
> URL: https://issues.apache.org/jira/browse/KAFKA-10643
> Project: Kafka
> Issue Type: Bug
> Components: streams
> Affects Versions: 2.6.0
> Reporter: Eran Levy
> Priority: Major
> Attachments: broker-4-11.csv, client-4-11.csv,
> client-d-9-11-11-2020.csv
>
>
> Kafka streams 2.6.0, brokers version 2.6.0. Kafka nodes are healthy, kafka
> streams app is healthy.
> Configured with static membership.
> Every 10 minutes (I assume cause of topic.metadata.refresh.interval.ms), I
> see the following group coordinator log for different stream consumers:
> INFO [GroupCoordinator 2]: Preparing to rebalance group **--**-stream in
> state PreparingRebalance with old generation 12244 (__consumer_offsets-45)
> (reason: Updating metadata for member
> ****-stream-11-1-013edd56-ed93-4370-b07c-1c29fbe72c9a)
> (kafka.coordinator.group.GroupCoordinator)
> and right after that the following log:
> INFO [GroupCoordinator 2]: Assignment received from leader for group
> **-**-stream for generation 12246 (kafka.coordinator.group.GroupCoordinator)
>
> Looked a bit on the kafka code and Im not sure that I get why such a thing
> happening - is this line described the situation that happens here re the
> "reason:"?[https://github.com/apache/kafka/blob/7ca299b8c0f2f3256c40b694078e422350c20d19/core/src/main/scala/kafka/coordinator/group/GroupCoordinator.scala#L311]
> I also dont see it happening too often in other kafka streams applications
> that we have.
> The only thing suspicious that I see around every hour that different pods of
> that kafka streams application throw this exception:
> {"timestamp":"2020-10-25T06:44:20.414Z","level":"INFO","thread":"**-**-stream-94561945-4191-4a07-ac1b-07b27e044402-StreamThread-1","logger":"org.apache.kafka.clients.FetchSessionHandler","message":"[Consumer
>
> clientId=**-**-stream-94561945-4191-4a07-ac1b-07b27e044402-StreamThread-1-restore-consumer,
> groupId=null] Error sending fetch request (sessionId=34683236, epoch=2872)
> to node
> 3:","context":"default","exception":"org.apache.kafka.common.errors.DisconnectException:
> null\n"}
> I came across this strange behaviour after stated to investigate a strange
> stuck rebalancing state after one of the members left the group and caused
> the rebalance to stuck - the only thing that I found is that maybe because
> that too often preparing to rebalance states, the app might affected of this
> bug - KAFKA-9752 ?
> I dont understand why it happens, it wasn't before I applied static
> membership to that kafka streams application (since around 2 weeks ago).
> Will be happy if you can help me
>
>
--
This message was sent by Atlassian Jira
(v8.3.4#803005)
