hello Sai, As you said Reducer starts only after completion of mapper....... U r doubting that y reducer is staring at 23% of mapper right? The answer is,there is a copy phase between mapper and reducer......after mapper as completed some tasks ,then those tasks are being copied to reducer......by copying also you can see that reducer % is increasing.......you also notice that only after mapper has completed 100% reducer completes its job 100%........thanq,Hope u will understand
On Thu, Apr 11, 2013 at 11:15 PM, Sai Sai <[email protected]> wrote: > I am running the wordcount from hadoop-examples, i am giving as input a > bunch of test files, i have noticed in the output given below reduce starts > when the map is at 23%, i was wondering if it is not right that reducers > will start only after the complete mapping is done which mean when map is > 100% then i thought the reducers will start. Why r the reducers starting > when map is still at 23%. > > 13/04/11 21:10:32 INFO mapred.JobClient: map 0% reduce 0% > 13/04/11 21:10:56 INFO mapred.JobClient: map 1% reduce 0% > 13/04/11 21:10:59 INFO mapred.JobClient: map 2% reduce 0% > 13/04/11 21:11:02 INFO mapred.JobClient: map 3% reduce 0% > 13/04/11 21:11:05 INFO mapred.JobClient: map 4% reduce 0% > 13/04/11 21:11:08 INFO mapred.JobClient: map 6% reduce 0% > 13/04/11 21:11:11 INFO mapred.JobClient: map 7% reduce 0% > 13/04/11 21:11:17 INFO mapred.JobClient: map 8% reduce 0% > 13/04/11 21:11:23 INFO mapred.JobClient: map 10% reduce 0% > 13/04/11 21:11:26 INFO mapred.JobClient: map 12% reduce 0% > 13/04/11 21:11:32 INFO mapred.JobClient: map 14% reduce 0% > 13/04/11 21:11:44 INFO mapred.JobClient: map 23% reduce 0% > 13/04/11 21:11:50 INFO mapred.JobClient: map 23% reduce 1% > 13/04/11 21:11:53 INFO mapred.JobClient: map 33% reduce 7% > 13/04/11 21:12:02 INFO mapred.JobClient: map 42% reduce 7% > > Please pour some light. > Thanks > Sai >
