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https://issues.apache.org/jira/browse/HADOOP-3632?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12607798#action_12607798
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Doug Cutting commented on HADOOP-3632:
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You could implement this yourself by having your map tasks periodically query
the jobtracker for percent completion and exit when things pass some threshold.
You could, e.g., define and use a subclass of MapRunnner that starts a thread
that polls the JobTracker for this every second or so. To check map progress:
float mapProgress = new
JobClient(job).getJob(job.get("mapred.job.id")).getMapProgress();
> 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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