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https://issues.apache.org/jira/browse/KAFKA-7657?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Guozhang Wang resolved KAFKA-7657.
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Resolution: Fixed
Assignee: Guozhang Wang
Fix Version/s: 2.2.0
> Invalid reporting of stream state in Kafka streams application
> --------------------------------------------------------------
>
> Key: KAFKA-7657
> URL: https://issues.apache.org/jira/browse/KAFKA-7657
> Project: Kafka
> Issue Type: Bug
> Components: streams
> Affects Versions: 2.0.1
> Reporter: Thomas Crowley
> Assignee: Guozhang Wang
> Priority: Major
> Labels: bug
> Fix For: 2.2.0
>
>
> We have a streams application with 3 instances running, two of which are
> reporting the state of REBALANCING even after they have been running for
> days. Restarting the application has no effect on the stream state.
> This seems suspect because each instance appears to be processing messages,
> and the kafka-consumer-groups CLI tool reports hardly any offset lag in any
> of the partitions assigned to the REBALANCING consumers. Each partition seems
> to be processing an equal amount of records too.
> Inspecting the state.dir on disk, it looks like the RocksDB state has been
> built and hovers at the expected size on disk.
> This problem has persisted for us after we rebuilt our Kafka cluster and
> reset topics + consumer groups in our dev environment.
> There is nothing in the logs (with level set to DEBUG) in both the broker or
> the application that suggests something exceptional has happened causing the
> application to be stuck REBALANCING.
> We are also running multiple streaming applications where this problem does
> not exist.
> Two differences between this application and our other streaming applications
> are:
> * We have processing.guarantee set to exactly_once
> * We are using a ValueTransformer which fetches from and puts data on a
> windowed state store
> The REBALANCING state is returned from both polling the state method of our
> KafkaStreams instance, and our custom metric which is derived from some logic
> in a KafkaStreams.StateListener class attached via the setStateListener
> method.
>
> While I have provided a bit of context, before I reply with some reproducible
> code - is there a simple way in which I can determine that my streams
> application is in a RUNNING state without relying on the same mechanisms as
> used above?
> Further, given that it seems like my application is actually running - could
> this perhaps be a bug to do with how the stream state is being reported (in
> the context of a transactional stream using the processor API)?
>
>
>
>
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