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From "Amar Kamat (JIRA)" <j...@apache.org>
Subject [jira] Updated: (MAPREDUCE-1533) reduce or remove usage of String.format() usage in CapacityTaskScheduler.updateQSIObjects
Date Fri, 05 Mar 2010 13:54:27 GMT

     [ https://issues.apache.org/jira/browse/MAPREDUCE-1533?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Amar Kamat updated MAPREDUCE-1533:
----------------------------------

    Attachment: mapreduce-1533-v1.4.patch

Attaching a patch for review. Instead of doing an in-line String.format(), a wrapper object
is passed with all the necessary values to construct the scheduling-info string. The scheduling
info is created lazily when toString() method is invoked on the wrapper object. 

> 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-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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