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From "Siddharth Seth (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (MAPREDUCE-5352) Optimize node local splits generated by CombineFileInputFormat
Date Fri, 28 Jun 2013 23:57:20 GMT

     [ https://issues.apache.org/jira/browse/MAPREDUCE-5352?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Siddharth Seth updated MAPREDUCE-5352:
--------------------------------------

    Attachment: MAPREDUCE-5352.2.txt

Updated patch with the comment changed to mentioned behaviour when maxSplitSize is set to
0.

This should ideally have it's own unit test - will try adding one in a subsequent patch. Submitting
this again for jenkins.
                
> Optimize node local splits generated by CombineFileInputFormat 
> ---------------------------------------------------------------
>
>                 Key: MAPREDUCE-5352
>                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-5352
>             Project: Hadoop Map/Reduce
>          Issue Type: Improvement
>    Affects Versions: 2.0.5-alpha
>            Reporter: Siddharth Seth
>            Assignee: Siddharth Seth
>         Attachments: MAPREDUCE-5352.1.txt, MAPREDUCE-5352.2.txt
>
>
> CombineFileInputFormat currently walks through all available nodes and generates multiple
(maxSplitsPerNode) splits on a single node before attempting to generate splits on subsequent
nodes. This ends up reducing the possibility of generating splits for subsequent nodes - since
these blocks will no longer be available for subsequent nodes. Allowing splits to go 1 block
above the max-split-size makes this worse.
> Allocating a single split per node in one iteration, should help increase the distribution
of splits across nodes - so the subsequent nodes will have more blocks to choose from.

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