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Hadoop, mail # user - mapred.map.tasks vs mapred.tasktracker.map.tasks.maximum


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Re: mapred.map.tasks vs mapred.tasktracker.map.tasks.maximum
Mohit Anchlia 2012-03-10, 01:19
What's the difference between setNumMapTasks and mapred.map.tasks?

On Fri, Mar 9, 2012 at 5:00 PM, Chen He <[EMAIL PROTECTED]> wrote:

> Hi Mohit
>
> " mapred.tasktracker.reduce(map).tasks.maximum " means how many reduce(map)
> slot(s) you can have on each tasktracker.
>
> "mapred.job.reduce(maps)" means default number of reduce (map) tasks your
> job will has.
>
> To set the number of mappers in your application. You can write like this:
>
> *configuration.setNumMapTasks(the number you want);*
>
> Chen
>
> Actually, you can just use configuration.set()
>
> On Fri, Mar 9, 2012 at 6:42 PM, Mohit Anchlia <[EMAIL PROTECTED]
> >wrote:
>
> > What's the difference between mapred.tasktracker.reduce.tasks.maximum and
> > mapred.map.tasks
> > **
>  > I want my data to be split against only 10 mappers in the entire
> cluster.
> > Can I do that using one of the above parameters?
> >
>