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https://issues.apache.org/jira/browse/HADOOP-3632?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12610118#action_12610118
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Severin Hacker commented on HADOOP-3632:
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I think this is related to HADOOP-707. I see exactly the same log with a
"ChannelException" and "output error" on the straggling map machine.
> Fix speculative execution or allow premature stop
> -------------------------------------------------
>
> Key: HADOOP-3632
> URL: https://issues.apache.org/jira/browse/HADOOP-3632
> Project: Hadoop Core
> Issue Type: New Feature
> Affects Versions: 0.16.3
> Reporter: Severin Hacker
> Original Estimate: 72h
> Remaining Estimate: 72h
>
> I run 50 iterations of a program with 500 maps and no reduces. I have noticed
> the following behaviour:
> In 50% of the iterations:
> 499 maps finish in 50 seconds
> 1 map finishes after 4 minutes
> Total time is 4 minutes.
> In 50% of the iterations:
> 500 maps finish in 50 seconds
> Total time is 50 seconds.
> It would be nice if I could tell hadoop to stop after 99% of the maps have
> finished (and not wait for that last straggler). In my application it's
> perfectly fine if I only get 99% of the results, as long as the straggler is
> not always using the same data.
> Please fix!
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