[
https://issues.apache.org/jira/browse/HADOOP-968?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Devaraj Das updated HADOOP-968:
-------------------------------
Attachment: 968-with-metrics-fix.patch
This patch addresses an issue to do with metrics reporting wherein
stopMonitoring was not called for the ReduceTask. This potentially could lead
to hung ReduceTasks after they are finished since the task JVM might not be
able to exit until the (non-daemon) monitoring thread goes away.
> Reduce shuffle and merge should be done a child JVM
> ---------------------------------------------------
>
> Key: HADOOP-968
> URL: https://issues.apache.org/jira/browse/HADOOP-968
> Project: Hadoop
> Issue Type: Improvement
> Components: mapred
> Affects Versions: 0.10.1
> Reporter: Owen O'Malley
> Assigned To: Devaraj Das
> Fix For: 0.13.0
>
> Attachments: 968-reindent.patch, 968-with-metrics-fix.patch,
> 968.apr06.patch, 968.apr10.patch, 968.apr14.patch, 968.apr14.patch, 968.patch
>
>
> The Reduce's shuffle and initial merge is done in the TaskTracker's JVM. It
> would be better to have it run in the Task's child JVM. The advantages are:
> 1. The class path and environment would be set up correctly.
> 2. User code doesn't need to be loaded into the TaskTracker.
> 3. Lower memory usage and contention in the TaskTracker.
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
