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Posted to mapreduce-issues@hadoop.apache.org by "Chris Douglas (JIRA)" <ji...@apache.org> on 2010/08/30 21:17:56 UTC

[jira] Commented: (MAPREDUCE-2043) TaskTrackerInstrumentation and JobTrackerInstrumentation should be public

    [ https://issues.apache.org/jira/browse/MAPREDUCE-2043?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12904296#action_12904296 ] 

Chris Douglas commented on MAPREDUCE-2043:
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Most of the listeners it defines are called during heartbeats... allowing administrators to put arbitrary code in that inner loop was not in its design. Have you looked at HADOOP-6728? If I understand the design doc, it allows a {{MetricsSink}} to be defined and notified outside of that cycle.

> TaskTrackerInstrumentation and JobTrackerInstrumentation should be public
> -------------------------------------------------------------------------
>
>                 Key: MAPREDUCE-2043
>                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-2043
>             Project: Hadoop Map/Reduce
>          Issue Type: Improvement
>          Components: tasktracker
>    Affects Versions: 0.22.0
>            Reporter: Philip Zeyliger
>            Assignee: Philip Zeyliger
>         Attachments: MAPREDUCE-2043.patch.txt
>
>
> Hadoop administrators can specify classes to be loaded as "TaskTrackerInstrumentation" and "JobTrackerInstrumentation" implementations, which, roughly, define listeners on TT and JT events.  Unfortunately, since the class has default access, extending it requires setting the extension's package to org.apache.hadoop.mapred, which seems like poor form.
> I propose we make the two instrumentation classes public, so they can be extended wherever.

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