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Hadoop, mail # user - Re: Set reducer capacity for a specific M/R job


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Re: Set reducer capacity for a specific M/R job
Nitin Pawar 2013-04-30, 10:07
The config you are setting is for job only

But if you want to reduce the slota on tasktrackers then you will need to
edit tasktracker conf and restart tasktracker
On Apr 30, 2013 3:30 PM, "Han JU" <[EMAIL PROTECTED]> wrote:

> Hi,
>
> I want to change the cluster's capacity of reduce slots on a per job
> basis. Originally I have 8 reduce slots for a tasktracker.
> I did:
>
> conf.set("mapred.tasktracker.reduce.tasks.maximum", "4");
> ...
> Job job = new Job(conf, ...)
>
>
> And in the web UI I can see that for this job, the max reduce tasks is
> exactly at 4, like I set. However hadoop still launches 8 reducer per
> datanode ... why is this?
>
> How could I achieve this?
> --
> *JU Han*
>
> Software Engineer Intern @ KXEN Inc.
> UTC   -  Université de Technologie de Compiègne
> *     **GI06 - Fouille de Données et Décisionnel*
>
> +33 0619608888
>
+
Han JU 2013-04-30, 10:09