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From: Harsh J <harsh@cloudera.com>
Date: Thu, 1 Nov 2012 22:25:15 +0530
Message-ID: 
 <CAOcnVr3mqTGAhXZg93FcefcS0ntTBjPj9EJFKCJnqPB5ne24mQ@mail.gmail.com>
Subject: Re: Set the number of maps
To: user@hadoop.apache.org
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It can't be set from the code this way - the slot property is applied
at the TaskTracker service level (as the name goes).

Since you're just testing at the moment, try to set these values,
restart TTs, and run your jobs again. You do not need to restart JT at
any point for tweaking these values.

On Thu, Nov 1, 2012 at 7:13 PM, Cogan, Peter (Peter)
<Peter.Cogan@alcatel-lucent.com> wrote:
> Hi
>
> I understand that the maximum number of concurrent map tasks is set by
> mapred.tasktracker.map.tasks.maximum  - however I wish to run with a smal=
ler
> number of maps (am testing disk IO). I thought that I could set that with=
in
> the main program using
>
> conf.set("mapred.tasktracker.map.tasks.maximuma", "4");
>
>
> to run with 4 maps =96 but that seems to have no impact. I know I could j=
ust
> change the mapred-site.xml and restart map reduce but that's kind of a pa=
in.
> Can it be set from within the code?
>
>
> Thanks
>
> Peter


--=20
Harsh J