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Posted to mapreduce-issues@hadoop.apache.org by "Arun C Murthy (JIRA)" <ji...@apache.org> on 2012/12/19 07:33:21 UTC

[jira] [Resolved] (MAPREDUCE-4891) Pluggable merge at reduce side

     [ https://issues.apache.org/jira/browse/MAPREDUCE-4891?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Arun C Murthy resolved MAPREDUCE-4891.
--------------------------------------

    Resolution: Duplicate

Duplicate of MAPREDUCE-4808
                
> Pluggable merge at reduce side
> ------------------------------
>
>                 Key: MAPREDUCE-4891
>                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-4891
>             Project: Hadoop Map/Reduce
>          Issue Type: New Feature
>    Affects Versions: 3.0.0
>            Reporter: Jerry Chen
>   Original Estimate: 504h
>  Remaining Estimate: 504h
>
> The current implementation of sort in MapReduce is cooperated by Map side sort and Reduce side merge.  MAPREDUCE-2454 provided pluggable sort at the Map side currently and pluggable shuffle at Reduce side, while no pluggable merger provided.
> Considering a general need of hash grouping and join, we may need to replace both the Map Sort and Reduce merge with a more light weight hash grouping alorithm. A general pluggable merge would help support this need.

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