[jira] [Commented] (KAFKA-2019) RoundRobinAssignor clusters by consumer

["Jiangjie Qin (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/KAFKA-2019?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14360659#comment-14360659 ] 

Jiangjie Qin commented on KAFKA-2019:
-------------------------------------

In this case is it that each consumer has large amount of consumer threads? Theoretically, in current code, a consumer should not take more than number-of-consumer-thread partitions than any other thread.
Anyway, I think sort threads based on hash code makes sense.

> RoundRobinAssignor clusters by consumer
> ---------------------------------------
>
>                 Key: KAFKA-2019
>                 URL: https://issues.apache.org/jira/browse/KAFKA-2019
>             Project: Kafka
>          Issue Type: Bug
>          Components: consumer
>            Reporter: Joseph Holsten
>            Assignee: Neha Narkhede
>            Priority: Minor
>         Attachments: 0001-sort-consumer-thread-ids-by-hashcode.patch
>
>
> When rolling out a change today, I noticed that some of my consumers are "greedy", taking far more partitions than others.
> The cause is that the RoundRobinAssignor is using a list of ConsumerThreadIds sorted by toString, which is {{ "%s-%d".format(consumer, threadId)}}. This causes each consumer's threads to be adjacent to each other.
> One possible fix would be to define ConsumerThreadId.hashCode, and sort by that.



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