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Date: Tue, 3 Jun 2008 10:06:45 -0700 (PDT)
From: "Mahadev konar (JIRA)" <jira@apache.org>
To: core-dev@hadoop.apache.org
Subject: [jira] Commented: (HADOOP-3427) In ReduceTask::fetchOutputs, wait
 for result can be improved slightly
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    [ https://issues.apache.org/jira/browse/HADOOP-3427?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12601995#action_12601995 ] 

Mahadev konar commented on HADOOP-3427:
---------------------------------------

+1 the patch looks good, though the fetchoutputs() needs refactoring urgently.

> In ReduceTask::fetchOutputs, wait for result can be improved slightly
> ---------------------------------------------------------------------
>
>                 Key: HADOOP-3427
>                 URL: https://issues.apache.org/jira/browse/HADOOP-3427
>             Project: Hadoop Core
>          Issue Type: Bug
>          Components: mapred
>            Reporter: Devaraj Das
>            Assignee: Devaraj Das
>             Fix For: 0.18.0
>
>         Attachments: 3427.patch, 3427.patch, 3427.patch
>
>
> The getCopyResult call in ReduceTask::fetchOutputs waits for 2 seconds if the results list is empty. This can be improved to wait only when sufficient number of fetches (above a certain threshold) have been scheduled. The threshold should ensure that all the fetcher threads would be busy enough, and in this case, the call to getCopyResult would return only when a fetcher thread wakes it up.

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