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Posted to mapreduce-issues@hadoop.apache.org by "Siddharth Seth (JIRA)" <ji...@apache.org> on 2013/07/31 03:30:47 UTC
[jira] [Updated] (MAPREDUCE-5352) Optimize node local splits
generated by CombineFileInputFormat
[ https://issues.apache.org/jira/browse/MAPREDUCE-5352?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Siddharth Seth updated MAPREDUCE-5352:
--------------------------------------
Attachment: MAPREDUCE-5352.3.txt
Updated patch with a unit test.
> 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, MAPREDUCE-5352.3.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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