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https://issues.apache.org/jira/browse/KAFKA-6127?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16390105#comment-16390105
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Guozhang Wang commented on KAFKA-6127:
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We are poll() with a timeout, but yes, admittedly today that timeout is not 
restrictedly respected since coordinator re-discover / re-join groups etc is 
not fully covered in that timeout. So I think the title may be changed to 
"Streams should not block unexpectedly" :P

> Streams should never block infinitely
> -------------------------------------
>
>                 Key: KAFKA-6127
>                 URL: https://issues.apache.org/jira/browse/KAFKA-6127
>             Project: Kafka
>          Issue Type: Bug
>          Components: streams
>    Affects Versions: 1.0.0
>            Reporter: Matthias J. Sax
>            Priority: Major
>
> Streams uses three consumer APIs that can block infinite: {{commitSync()}}, 
> {{committed()}}, and {{position()}}.
> If we block within one operation, the whole {{StreamThread}} would block, and 
> the instance does not make any progress, becomes unresponsive (for example, 
> {{KafkaStreams#close()}} suffers), and we also might drop out of the consumer 
> group.
> We might consider to use {{wakeup()}} calls to unblock those operations to 
> keep {{StreamThread}} in a responsive state.
> Note: there are discussion to add timeout to those calls, and thus, we could 
> get {{TimeoutExceptions}}. This would be easier to handle than using 
> {{wakeup()}}. Thus, we should keep an eye on those discussions. 



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