Thanks Rishi, My question is answered.
regards, Lin On Sun, Dec 23, 2012 at 12:09 AM, Rishi Yadav <[email protected]> wrote: > Hi Lin, > > Reduce task starts as soon as output is ready from Mappers. The reduce > method does not get called until all Mappers are done. If that's not the > case, all operations which are not commutative and associative will yield > incorrect result. > > > > Thanks and Regards, > > Rishi Yadav > > (o) 408.988.2000x113 || (f) 408.716.2726 > > InfoObjects Inc || http://www.infoobjects.com *(Big Data Solutions)* > > *INC 500 Fastest growing company in 2012 || 2011* > > *Best Place to work in Bay Area 2012 - *SF Business Times and the Silicon > Valley / San Jose Business Journal > > 2041 Mission College Boulevard, #280 || Santa Clara, CA 95054 > > > > > On Sat, Dec 22, 2012 at 5:25 AM, Lin Ma <[email protected]> wrote: > >> Hi guys, >> >> Supposing in a Hadoop job, there are both mappers and reducers. My >> question is, reducer tasks cannot begin until all mapper tasks complete? If >> so, why designed in this way? >> >> thanks in advance, >> Lin >> > >
