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From "Vinod K V (JIRA)" <j...@apache.org>
Subject [jira] Commented: (MAPREDUCE-1533) reduce or remove usage of String.format() usage in CapacityTaskScheduler.updateQSIObjects
Date Tue, 13 Apr 2010 18:08:57 GMT

    [ https://issues.apache.org/jira/browse/MAPREDUCE-1533?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12856524#action_12856524

Vinod K V commented on MAPREDUCE-1533:

I am not able to grant permissions for the patch to apache.

Something got mixed up when bringing back JIRA up after the recent security breach? Anyone
who can grant permissions? Or is it a general problem warranting an INFRA ticket?

> reduce or remove usage of String.format() usage in CapacityTaskScheduler.updateQSIObjects
> -----------------------------------------------------------------------------------------
>                 Key: MAPREDUCE-1533
>                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-1533
>             Project: Hadoop Map/Reduce
>          Issue Type: Bug
>    Affects Versions: 0.20.1
>            Reporter: Rajesh Balamohan
>            Assignee: Amar Kamat
>         Attachments: MAPREDUCE-1533-and-others-20100413.1.txt, mapreduce-1533-v1.4.patch
> When short jobs are executed in hadoop with OutOfBandHeardBeat=true, JT executes heartBeat()
method heavily. This internally makes a call to CapacityTaskScheduler.updateQSIObjects().

> CapacityTaskScheduler.updateQSIObjects(), internally calls String.format() for setting
the job scheduling information. Based on the datastructure size of "jobQueuesManager" and
"queueInfoMap", the number of times String.format() gets executed becomes very high. String.format()
internally does pattern matching which turns to be out very heavy (This was revealed while
profiling JT. Almost 57% of time was spent in CapacityScheduler.assignTasks(), out of which
String.format() took 46%.
> Would it be possible to do String.format() only at the time of invoking JobInProgress.getSchedulingInfo?.
This might reduce the pressure on JT while processing heartbeats. 

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