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https://issues.apache.org/jira/browse/HADOOP-4396?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12640600#action_12640600
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Raghu Angadi commented on HADOOP-4396:
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I think this highlights some issues that are worth considering for improvement.
It looks as though some mapper that gets slightly behind will end up getting
disproportionately hard.. slowing the progress much worse than one would
expect. And it does not even need to be any hardware degredation. This kind of
bad feedback gets only worse as the cluster size increases.
> sort on 400 nodes is now slower than in 18
> ------------------------------------------
>
> Key: HADOOP-4396
> URL: https://issues.apache.org/jira/browse/HADOOP-4396
> Project: Hadoop Core
> Issue Type: Bug
> Components: mapred
> Affects Versions: 0.19.0
> Reporter: Jothi Padmanabhan
> Assignee: Jothi Padmanabhan
> Priority: Blocker
> Fix For: 0.19.0
>
> Attachments: 4396-v3.patch
>
>
> Sort on 400 nodes on hadoop release 18 takes about 29 minutes, but with the
> 19 branch takes about 32 minutes. This behavior is consistent.
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