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

    Assignee: Amar Kamat

> 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
>
> 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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