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Posted to mapreduce-dev@hadoop.apache.org by "Boris Ryakhovskiy (JIRA)" <ji...@apache.org> on 2012/10/09 16:13:02 UTC

[jira] [Created] (MAPREDUCE-4715) Heap memory growing when JVM reuse option enabled

Boris Ryakhovskiy created MAPREDUCE-4715:
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             Summary: Heap memory growing when JVM reuse option enabled
                 Key: MAPREDUCE-4715
                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-4715
             Project: Hadoop Map/Reduce
          Issue Type: Bug
          Components: job submission
    Affects Versions: 0.20.2
         Environment: Linux, cdh3u5
            Reporter: Boris Ryakhovskiy
            Priority: Minor
         Attachments: VisualVM_screenshot.png

When mapred.job.reuse.jvm.num.tasks option is set to 100 or more tasks, JVM fails with "java.lang.OutOfMemoryError: Java heap space" error message. Jobs itself are small and job heap size is set to -Xmx200m .
It looks like the reason of the issue is a FileSystem$Cache object which collects JobConf objects from all jobs which were executed in current JVM. GC root for the FileSystem$Cache is ApplicationShutdownHooks class (cannot attach screenshot from visualvm)
In my case each of JobConf objects allocates ~500K (50M total in case of 100 jobs).

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