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Posted to mapreduce-issues@hadoop.apache.org by "nicu marasoiu (JIRA)" <ji...@apache.org> on 2013/06/13 13:35:20 UTC

[jira] [Assigned] (MAPREDUCE-5287) Create a generic InputFormat wrapping any other InputFormat, to control the number of map tasks

     [ https://issues.apache.org/jira/browse/MAPREDUCE-5287?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

nicu marasoiu reassigned MAPREDUCE-5287:
----------------------------------------

    Assignee: nicu marasoiu  (was: Owen O'Malley)
    
> Create a generic InputFormat wrapping any other InputFormat, to control the number of map tasks
> -----------------------------------------------------------------------------------------------
>
>                 Key: MAPREDUCE-5287
>                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-5287
>             Project: Hadoop Map/Reduce
>          Issue Type: Improvement
>          Components: mrv1, performance
>            Reporter: nicu marasoiu
>            Assignee: nicu marasoiu
>            Priority: Minor
>   Original Estimate: 4h
>  Remaining Estimate: 4h
>
> I wrote a generic InputFormat that wraps any other InputFormat, and creates CompositeInputSplits to reduce the number of map tasks in a controllable manner while preserving data locality. A correspondent CompositeRecordReader is written to iterate through underlying RecordReaders as created by the underlying InputFormat for each underlying raw split.
> An application to this is to group TableSplits when the raw splits are coming from multiple regions and are filtered with key ranges. We use this to shard/distribute a time based incremental access to an hbase table.

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