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From Shahab Yunus <shahab.yu...@gmail.com>
Subject Re: Reduce Task Clarification
Date Wed, 14 Aug 2013 12:55:43 GMT
Also Sam, following are is a link giving example about how to implement
secondary sort and what it is...



On Tue, Aug 13, 2013 at 3:51 PM, Sam Garrett <sam@actionx.com> wrote:

> I am working on a MapReduce job where I would like to have the output
> sorted by a LongWritable value. I read the Anatomy of a MapReduce Run in
> the Definitive Guide and it didn't say explicitly whether reduce() gets
> called only once per map output key. If it does get called only once I was
> thinking that I could use this:
> http://hadoop.apache.org/docs/current/api/org/apache/hadoop/mapreduce/Job.html#setSortComparatorClass(java.lang.Class)to
do the sorting.
> Thank you for your time.
> --
> Sam Garrett
> ActionX, NYC

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