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https://issues.apache.org/jira/browse/KAFKA-3297?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15788229#comment-15788229
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Ewen Cheslack-Postava commented on KAFKA-3297:
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Yeah, part of the improvement of KIP-49 seems to be included in step 2 of the
algorithm (start from the least loaded consumers rather than just using a
CircularIterator). But there are a few more improvements (specifically in
optimizing the order of processing the topics) that would still probably need
to be incorporated.
> More optimally balanced partition assignment strategy (new consumer)
> --------------------------------------------------------------------
>
> Key: KAFKA-3297
> URL: https://issues.apache.org/jira/browse/KAFKA-3297
> Project: Kafka
> Issue Type: Improvement
> Components: consumer
> Reporter: Andrew Olson
> Assignee: Andrew Olson
> Fix For: 0.10.2.0
>
>
> While the roundrobin partition assignment strategy is an improvement over the
> range strategy, when the consumer topic subscriptions are not identical
> (previously disallowed but will be possible as of KAFKA-2172) it can produce
> heavily skewed assignments. As suggested
> [here|https://issues.apache.org/jira/browse/KAFKA-2172?focusedCommentId=14530767&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-14530767]
> it would be nice to have a strategy that attempts to assign an equal number
> of partitions to each consumer in a group, regardless of how similar their
> individual topic subscriptions are. We can accomplish this by tracking the
> number of partitions assigned to each consumer, and having the partition
> assignment loop assign each partition to a consumer interested in that topic
> with the least number of partitions assigned.
> Additionally, we can optimize the distribution fairness by adjusting the
> partition assignment order:
> * Topics with fewer consumers are assigned first.
> * In the event of a tie for least consumers, the topic with more partitions
> is assigned first.
> The general idea behind these two rules is to keep the most flexible
> assignment choices available as long as possible by starting with the most
> constrained partitions/consumers.
> This JIRA addresses the new consumer. For the original high-level consumer,
> see KAFKA-2435.
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