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Posted to general@hadoop.apache.org by Rahul Malviya <rm...@apple.com> on 2010/09/14 19:24:39 UTC

Number of Mappers

Hi 

I am using Pig jobs to run on Hadoop but always it runs 4 mappers simultaneously. 

How can I increase the number of simultaneous mappers to run ?

What config do I have to change ?

Thanks,
Rahul

Re: Number of Mappers

Posted by Jeff Zhang <zj...@gmail.com>.

Hi Rahul,

You can not determined set the mapper number as reducer number. The
mapper number is determined by the your InputFormat. If you are using
PigStorage, then the InputFormat is PigTextInputFormat which is a
subclass of TextInputFormat. You can refer TextInputFormat.getSplits()
to see how it split the input.

On Wed, Sep 15, 2010 at 1:24 AM, Rahul Malviya <rm...@apple.com> wrote:
> Hi
>
> I am using Pig jobs to run on Hadoop but always it runs 4 mappers simultaneously.
>
> How can I increase the number of simultaneous mappers to run ?
>
> What config do I have to change ?
>
> Thanks,
> Rahul

-- 
Best Regards

Jeff Zhang