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https://issues.apache.org/jira/browse/KAFKA-6199?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16266760#comment-16266760
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Robin Tweedie commented on KAFKA-6199:
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We tried to prove that this client was the culprit, but we were unable to stop
the heap growth after making changes to it.
Any thoughts on the heap dump pictures I shared [~ijuma] [~tedyu] ?
> Single broker with fast growing heap usage
> ------------------------------------------
>
> Key: KAFKA-6199
> URL: https://issues.apache.org/jira/browse/KAFKA-6199
> Project: Kafka
> Issue Type: Bug
> Affects Versions: 0.10.2.1
> Environment: Amazon Linux
> Reporter: Robin Tweedie
> Attachments: Screen Shot 2017-11-10 at 1.55.33 PM.png, Screen Shot
> 2017-11-10 at 11.59.06 AM.png, dominator_tree.png, merge_shortest_paths.png,
> path2gc.png
>
>
> We have a single broker in our cluster of 25 with fast growing heap usage
> which necessitates us restarting it every 12 hours. If we don't restart the
> broker, it becomes very slow from long GC pauses and eventually has
> {{OutOfMemory}} errors.
> See {{Screen Shot 2017-11-10 at 11.59.06 AM.png}} for a graph of heap usage
> percentage on the broker. A "normal" broker in the same cluster stays below
> 50% (averaged) over the same time period.
> We have taken heap dumps when the broker's heap usage is getting dangerously
> high, and there are a lot of retained {{NetworkSend}} objects referencing
> byte buffers.
> We also noticed that the single affected broker logs a lot more of this kind
> of warning than any other broker:
> {noformat}
> WARN Attempting to send response via channel for which there is no open
> connection, connection id 13 (kafka.network.Processor)
> {noformat}
> See {{Screen Shot 2017-11-10 at 1.55.33 PM.png}} for counts of that WARN log
> message visualized across all the brokers (to show it happens a bit on other
> brokers, but not nearly as much as it does on the "bad" broker).
> I can't make the heap dumps public, but would appreciate advice on how to pin
> down the problem better. We're currently trying to narrow it down to a
> particular client, but without much success so far.
> Let me know what else I could investigate or share to track down the source
> of this leak.
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