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From "Luke Lu (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (MAPREDUCE-4851) add lifecycle to Comparators
Date Thu, 20 Dec 2012 01:33:12 GMT

    [ https://issues.apache.org/jira/browse/MAPREDUCE-4851?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13536673#comment-13536673
] 

Luke Lu commented on MAPREDUCE-4851:
------------------------------------

You still haven't explained why lifecycle is needed for comparators? It seems to me that you
only need task level lifecycle, which should work with JVM reuse as well.
                
> add lifecycle to Comparators
> ----------------------------
>
>                 Key: MAPREDUCE-4851
>                 URL: https://issues.apache.org/jira/browse/MAPREDUCE-4851
>             Project: Hadoop Map/Reduce
>          Issue Type: Improvement
>            Reporter: Radim Kolar
>              Labels: mrv2
>
> current mapreduce api is using RawComparator interface in:
> setGroupingComparatorClass
> setSortComparatorClass
> This interface has no lifecycle support. I propose to change that methods to take argument
new class implements RawComparator with setup and cleanup methods. 
> This will leave existing code with RawComparator alone, Providing some backward compatibility.
> new class: 
> class SortComparator implements RawComparator

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