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https://issues.apache.org/jira/browse/HADOOP-1719?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12520862
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Hadoop QA commented on HADOOP-1719:
-----------------------------------
-1, new javadoc warnings
The javadoc tool appears to have generated warning messages when testing the
latest attachment
http://issues.apache.org/jira/secure/attachment/12364036/1719.1.patch against
trunk revision r566886.
Test results:
http://lucene.zones.apache.org:8080/hudson/job/Hadoop-Patch/566/testReport/
Console output:
http://lucene.zones.apache.org:8080/hudson/job/Hadoop-Patch/566/console
Please note that this message is automatically generated and may represent a
problem with the automation system and not the patch.
> Improve the utilization of shuffle copier threads
> -------------------------------------------------
>
> Key: HADOOP-1719
> URL: https://issues.apache.org/jira/browse/HADOOP-1719
> Project: Hadoop
> Issue Type: Improvement
> Components: mapred
> Reporter: Devaraj Das
> Assignee: Devaraj Das
> Fix For: 0.15.0
>
> Attachments: 1719.1.patch, 1719.patch
>
>
> In the current design, the scheduling of copies is done and the scheduler
> (the main loop in fetchOutputs) won't schedule anything until it hears back
> from at least one of the copier threads. Due to this, the main loop won't
> query the TaskTracker asking for new map locations and may not be using all
> the copiers effectively. This may not be an issue for small-sized map
> outputs, where at steady state, the frequency of such notifications is
> frequent.
> Ideally, we should schedule all what we can, and, depending on how busy we
> currently are, query the tasktracker for more map locations.
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