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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
if you do not specify  setNumMapTasks, by default, system will use the
number you configured  for "mapred.map.tasks" in the conf/mapred-site.xml
file.

On Fri, Mar 9, 2012 at 7:19 PM, Mohit Anchlia <[EMAIL PROTECTED]>wrote:

> 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?
> > >
> >
>