Hi, Data is divided to mappers depending on your inputformat. Usually the number of mappers = number of blocks.
Daniel > On 22 באוג׳ 2015, at 09:02, ☼ R Nair (रविशंकर नायर) > <[email protected]> wrote: > > Hi , > > The mappers depend on source data only. But data definitely is going through > all mappers, so I should get number of map jpbs as my output right? Instead I > am getting only one. > > Thanks and regards, > Ravion > >> On Fri, Aug 21, 2015 at 1:35 PM, ☼ R Nair (रविशंकर नायर) >> <[email protected]> wrote: >> All, >> >> I have three mappers, followed by a reducer. I executed the map reduce >> successfully. The reported output shows that number of mappers executed is 1 >> and number of reducers is also 1. Though number of reducers are correct, >> won't we be getting number of mappers as 3 , since I have three mapper >> classes connected by ChainMapper? >> >> O/P given below (snippet) :- >> >> Job Counters >> Launched map tasks=1 >> Launched reduce tasks=1 >> Data-local map tasks=1 >> Total time spent by all maps in occupied slots (ms)=8853 >> Total time spent by all reduces in occupied slots (ms)=9900 >> Total time spent by all map tasks (ms)=8853 >> Total time spent by all reduce tasks (ms)=9900 >> Total vcore-seconds taken by all map tasks=8853 >> Total vcore-seconds taken by all reduce tasks=9900 >> Total megabyte-seconds taken by all map tasks=9065472 >> Total megabyte-seconds taken by all reduce tasks=10137600 >> >> >> What I guess is, since the output is passing through Context, the internal >> connected mappers are not caught by job counter, am I correct ? >> >> Best, Ravion >
