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https://issues.apache.org/jira/browse/HADOOP-16248?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16841678#comment-16841678
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Alexis Daboville commented on HADOOP-16248:
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alexis.dabovi...@gmail.com should do. Thanks.

> Fix MutableQuantiles memory leak
> --------------------------------
>
>                 Key: HADOOP-16248
>                 URL: https://issues.apache.org/jira/browse/HADOOP-16248
>             Project: Hadoop Common
>          Issue Type: Bug
>    Affects Versions: 2.9.2
>            Reporter: Alexis Daboville
>            Priority: Major
>         Attachments: HADOOP-16248.00.patch, mutable-quantiles-leak.png, 
> mutable-quantiles.patch
>
>
> In some circumstances (high GC, high CPU usage, creating lots of
>  S3AFileSystem) it is possible for MutableQuantiles::scheduler [1] to fall
>  behind processing tasks that are submitted to it; because tasks are
>  submitted on a regular schedule, the unbounded queue backing the
>  {{ExecutorService}} might grow to several gigs [2]. By using
>  {{scheduleWithFixedDelay}} instead, we ensure that under pressure this leak 
> won't
>  happen. In order to mitigate the growth, a simple fix [3] is proposed, 
> simply replacing {{scheduler.scheduleAtFixedRate}} by 
> {{scheduler.scheduleWithFixedDelay}}.
> [1] it is single threaded and shared across all instances of 
> {{MutableQuantiles}}: 
> [https://github.com/apache/hadoop/blob/trunk/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/metrics2/lib/MutableQuantiles.java#L66-L68]
> [2] see attached mutable-quantiles-leak.png.
> [3] mutable-quantiles.patch



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