The number of map tasks is determined by InputSplit.
On Wednesday, June 30, 2010, Pierre ANCELOT <[email protected]> wrote: > Hi, > Okay, so, if I set the 20 by default, I could maybe limit the number of > concurrent maps per node instead? > job.setNumReduceTasks exists but I see no equivalent for maps, though I > think there was a setNumMapTasks before... > Was it removed? Why? > Any idea about how to acheive this? > > Thank you. > > > On Wed, Jun 30, 2010 at 12:08 PM, Amareshwari Sri Ramadasu < > [email protected]> wrote: > >> Hi Pierre, >> >> "mapred.tasktracker.map.tasks.maximum" is a cluster level configuration, >> cannot be set per job. It is loaded only while bringing up the TaskTracker. >> >> Thanks >> Amareshwari >> >> On 6/30/10 3:05 PM, "Pierre ANCELOT" <[email protected]> wrote: >> >> Hi everyone :) >> There's something I'm probably doing wrong but I can't seem to figure out >> what. >> I have two hadoop programs running one after the other. >> This is done because they don't have the same needs in term of processor in >> memory, so by separating them I optimize each task better. >> Fact is, I need for the first job on every node >> mapred.tasktracker.map.tasks.maximum set to 12. >> For the second task, I need it to be set to 20. >> so by default I set it to 12 and in the second job's code, I set this: >> >> Configuration hadoopConfiguration = new Configuration(); >> hadoopConfiguration.setInt("mapred.tasktracker.map.tasks.maximum", >> 20); >> >> But when running the job, instead of having the 20 tasks on each node as >> expected, I have 12.... >> Any idea please? >> >> Thank you. >> Pierre. >> >> >> -- >> http://www.neko-consulting.com >> Ego sum quis ego servo >> "Je suis ce que je protège" >> "I am what I protect" >> >> > > > -- > http://www.neko-consulting.com > Ego sum quis ego servo > "Je suis ce que je protège" > "I am what I protect" >
