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Date: Fri, 11 Jun 2010 17:15:24 -0400 (EDT)
From: "Scott Chen (JIRA)" <jira@apache.org>
To: mapreduce-issues@hadoop.apache.org
Subject: [jira] Commented: (MAPREDUCE-1829)
 JobInProgress.findSpeculativeTask should use min() to find the candidate
 instead of sort()
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    [ https://issues.apache.org/jira/browse/MAPREDUCE-1829?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12877969#action_12877969 ] 

Scott Chen commented on MAPREDUCE-1829:
---------------------------------------

I was thinking of "latest" because we are using LateComparator which compares the finish time.
But as you explained, I think "slowest" is also a good name.

+1

> JobInProgress.findSpeculativeTask should use min() to find the candidate instead of sort()
> ------------------------------------------------------------------------------------------
>
>                 Key: MAPREDUCE-1829
>                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-1829
>             Project: Hadoop Map/Reduce
>          Issue Type: Improvement
>          Components: jobtracker
>    Affects Versions: 0.22.0
>            Reporter: Scott Chen
>            Assignee: Scott Chen
>             Fix For: 0.22.0
>
>         Attachments: MAPREDUCE-1829-20100610.txt, MAPREDUCE-1829.txt
>
>
> findSpeculativeTask needs only one candidate to speculate so it does not need to sort the whole list. It may looks OK but someone can still submit big jobs with small slow task thresholds. In this case, this sorting becomes expensive.

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