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From "Todd Lipcon (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (MAPREDUCE-2740) MultipleOutputs in new API creates needless TaskAttemptContexts
Date Mon, 01 Aug 2011 17:52:09 GMT

    [ https://issues.apache.org/jira/browse/MAPREDUCE-2740?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13073629#comment-13073629
] 

Todd Lipcon commented on MAPREDUCE-2740:
----------------------------------------

I ran TestMultipleOutputs and TestMRMultipleOutputs and they pass. Those are the only tests
which reference the changed code. I'll commit this to trunk momentarily

> MultipleOutputs in new API creates needless TaskAttemptContexts
> ---------------------------------------------------------------
>
>                 Key: MAPREDUCE-2740
>                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-2740
>             Project: Hadoop Map/Reduce
>          Issue Type: Bug
>    Affects Versions: 0.23.0
>            Reporter: Todd Lipcon
>            Assignee: Todd Lipcon
>             Fix For: 0.23.0
>
>         Attachments: mr-2740.txt
>
>
> MultipleOutputs.write creates a new TaskAttemptContext, which we've seen to take a significant
amount of CPU. The TaskAttemptContext constructor creates a JobConf, gets current UGI, etc.
I don't see any reason it needs to do this, instead of just creating a single TaskAttemptContext
when the InputFormat is created (or lazily but cached as a member)

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