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From Jothi Padmanabhan <joth...@yahoo-inc.com>
Subject Re: setGroupingComparatorClass() or setOutputValueGroupingComparator() does not work for Combiner
Date Thu, 07 May 2009 11:53:48 GMT
OutputValueGroupingComparator is used only at the reducer. AFAIK, I do not
think you can have a different comparator for combiners.

Jothi


On 5/7/09 3:32 PM, "zsongbo" <zsongbo@gmail.com> wrote:

> Hi all,
> I have a application want the rules of sorting and grouping use
> different Comparator.
> 
> I had tested 0.19.1 and 0.20.0 about this function, but both do not work for
> Combiner.
> 
> In 0.19.1, I use job.setOutputValueGroupingComparator(), and
> in 0.20.0, I use job.setGroupingComparatorClass()
> 
> This function is ok for reduce phase, the reduce phase can group the keys by
> above Comparator, and sort by default comparator of the key class.
> 
> But I want the combiner can use a separator comparator for group, different
> from sorting, is it possible?
> 
> Schubert


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