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Posted to common-dev@hadoop.apache.org by "dhruba borthakur (JIRA)" <ji...@apache.org> on 2008/08/29 03:05:44 UTC

[jira] Updated: (HADOOP-4018) limit memory usage in jobtracker

     [ https://issues.apache.org/jira/browse/HADOOP-4018?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

dhruba borthakur updated HADOOP-4018:
-------------------------------------

    Attachment: maxSplits.patch

Configure the maximum number of splits that a job can have. This helps in eliminating rouge jobs from permanently stalling the Job Tracker. This patch is for review purposes only.

> limit memory usage in jobtracker
> --------------------------------
>
>                 Key: HADOOP-4018
>                 URL: https://issues.apache.org/jira/browse/HADOOP-4018
>             Project: Hadoop Core
>          Issue Type: Bug
>          Components: mapred
>            Reporter: dhruba borthakur
>            Assignee: dhruba borthakur
>         Attachments: maxSplits.patch
>
>
> We have seen instances when a user submitted a job with many thousands of mappers. The JobTracker was running with 3GB heap, but it was still not enough to prevent memory trashing from Garbage collection; effectively the Job Tracker was not able to serve jobs and had to be restarted.
> One simple proposal would be to limit the maximum number of tasks per job. This can be a configurable parameter. Is there other things that eat huge globs of memory in job Tracker?

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