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From li ping <li.j...@gmail.com>
Subject Re: When a Reduce Task starts?
Date Tue, 21 Dec 2010 01:53:38 GMT
I think the reduce can be started before all of the map finished.
See the configration item in mapred-site.xml

<property>
  <name>mapred.reduce.slowstart.completed.maps</name>
  <value>0.05</value>
  <description>Fraction of the number of maps in the job which should be
  complete before reduces are scheduled for the job.
  </description>
</property>

Correct me, if I'm wrong.

On Tue, Dec 21, 2010 at 4:18 AM, Harsh J <qwertymaniac@gmail.com> wrote:

> Hi,
>
> On Tue, Dec 21, 2010 at 12:03 AM, Pedro Costa <psdc1978@gmail.com> wrote:
> > 1 - A reduce task should start only when a map task ends ?
> Only when all map()s finish, the reduce() is called, yes.
> >
> > --
> > Pedro
> >
>
>
>
> --
> Harsh J
> www.harshj.com
>



-- 
-----李平

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