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https://issues.apache.org/jira/browse/KAFKA-5611?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16099599#comment-16099599
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Panos Skianis commented on KAFKA-5611:
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Just an observation based on metrics & logs on the client side and the
consumer-group command.
In the last occurrence of this problem, the assigned partitions metric on the
consumer side shows 0 but the client seems to be heartbeating as usual. The
consumer group command through show that the particular consumer has 24
partitions assigned to it.
Is the above a valid scenario? Does that mean that we have a healthy consumer
that has been assigned no partitions and it will never get any until there is a
reason to rebalance?
Secondly, we were looking at the same code and were thinking (since there is no
stacktrace at the mo) that wakeup call was against the the client.poll(future)
line in the same code where you applied the patch. Couldn't that be the case?
What would happen then?
> One or more consumers in a consumer-group stop consuming after rebalancing
> --------------------------------------------------------------------------
>
> Key: KAFKA-5611
> URL: https://issues.apache.org/jira/browse/KAFKA-5611
> Project: Kafka
> Issue Type: Bug
> Affects Versions: 0.10.2.0
> Reporter: Panos Skianis
> Assignee: Jason Gustafson
> Attachments: bad-server-with-more-logging-1.tar.gz, kka02, Server 1,
> Server 2, Server 3
>
>
> Scenario:
> - 3 zookeepers, 4 Kafkas. 0.10.2.0, with 0.9.0 compatibility still on
> (other apps need it but the one mentioned below is already on kafka 0.10.2.0
> client).
> - 3 servers running 1 consumer each under the same consumer groupId.
> - Servers seem to be consuming messages happily but then there is a timeout
> to an external service that causes our app to restart the Kafka Consumer on
> one of the servers (this is by design). That causes rebalancing of the group
> and upon restart of one of the Consumers seem to "block".
> - Server 3 is where the problems occur.
> - Problem fixes itself either by restarting one of the 3 servers or cause
> the group to rebalance again by using the console consumer with the
> autocommit set to false and using the same group.
>
> Note:
> - Haven't managed to recreate it at will yet.
> - Mainly happens in production environment, often enough. Hence I do not
> have any logs with DEBUG/TRACE statements yet.
> - Extracts from log of each app server are attached. Also the log of the
> kafka that seems to be dealing with the related group and generations.
> - See COMMENT lines in the files for further info.
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