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Date: Wed, 5 May 2010 00:58:03 -0400 (EDT)
From: "dhruba borthakur (JIRA)" <jira@apache.org>
To: mapreduce-issues@hadoop.apache.org
Subject: [jira] Commented: (MAPREDUCE-1752) Implement getFileBlockLocations
 in HarFilesystem
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    [ https://issues.apache.org/jira/browse/MAPREDUCE-1752?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12864148#action_12864148 ] 

dhruba borthakur commented on MAPREDUCE-1752:
---------------------------------------------

Sounds like a good idea. +1

The idea is to make the contents of a Har file work well with FileInputFormat or CombineFileInputFormat, isn't it? In that case, you can see TestCombineFileInputFormat and see if u can extend it to test the case when the input file(s) are har files.

> Implement getFileBlockLocations in HarFilesystem
> ------------------------------------------------
>
>                 Key: MAPREDUCE-1752
>                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-1752
>             Project: Hadoop Map/Reduce
>          Issue Type: Improvement
>            Reporter: Dmytro Molkov
>
> To efficiently run map reduce on the data that has been HAR'ed it will be great to actually implement getFileBlockLocations for a given filename.
> This way the JobTracker will have information about data locality and will schedule tasks appropriately.
> I believe the overhead introduced by doing lookups in the index files can be smaller than that of copying data over the wire.
> Will upload the patch shortly, but would love to get some feedback on this. And any ideas on how to test it are very welcome.

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