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 <mohitanch...@gmail.com>wrote: > What's the difference between setNumMapTasks and mapred.map.tasks? > > On Fri, Mar 9, 2012 at 5:00 PM, Chen He <airb...@gmail.com> 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 <mohitanch...@gmail.com > > >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? > > > > > >
