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Posted to mapreduce-dev@hadoop.apache.org by Samaneh Shokuhi <sa...@gmail.com> on 2012/09/30 21:06:47 UTC

sorting mechanism

Hi,
I want to know about the sorting mechanism in mapper and reducer,As i
understood from document the result from mapper get sorted before sent to
reducer.
Could you please tell me which  part of hadoop implementation is
responsible for this sort.

Also please let me know which classes are responsible for sorting in
reducer phase.

Best Regards,
Samaneh

Re: sorting mechanism

Posted by Arun C Murthy <ac...@hortonworks.com>.

Look at MapTask.java (MapOutputBuffer) and ReduceTask.java and follow the merge code.

Arun

On Sep 30, 2012, at 12:06 PM, Samaneh Shokuhi wrote:

> Hi,
> I want to know about the sorting mechanism in mapper and reducer,As i
> understood from document the result from mapper get sorted before sent to
> reducer.
> Could you please tell me which  part of hadoop implementation is
> responsible for this sort.
> 
> Also please let me know which classes are responsible for sorting in
> reducer phase.
> 
> Best Regards,
> Samaneh

--
Arun C. Murthy
Hortonworks Inc.
http://hortonworks.com/