[jira] [Commented] (MAPREDUCE-2187) map tasks timeout during sorting

["Anupam Seth (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/MAPREDUCE-2187?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13045475#comment-13045475 ] 

Anupam Seth commented on MAPREDUCE-2187:
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As commented by Luke in MAPREDUCE-2177, the combiner code path doesn't report progress at some configured interval, so it can timeout when map output is large. A proposed fix is in CombineOutputCollector#collect to report progress a la Merger#writeFile.


> map tasks timeout during sorting
> --------------------------------
>
>                 Key: MAPREDUCE-2187
>                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-2187
>             Project: Hadoop Map/Reduce
>          Issue Type: Bug
>    Affects Versions: 0.20.2
>            Reporter: Gianmarco De Francisci Morales
>
> During the execution of a large job, the map tasks timeout:
> {code}
> INFO mapred.JobClient: Task Id : attempt_201010290414_60974_m_000057_1, Status : FAILED
> Task attempt_201010290414_60974_m_000057_1 failed to report status for 609 seconds. Killing!
> {code}
> The bug is in the fact that the mapper has already finished, and, according to the logs, the timeout occurs during the merge sort phase.
> The intermediate data generated by the map task is quite large. So I think this is the problem.
> The logs show that the merge-sort was running for 10 minutes when the task was killed.
> I think the mapred.Merger should call Reporter.progress() somewhere.

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