how many reducer do you have? You should make this value larger then 1 to make mapper and reducer run concurrently. You can set this value from JobConf.*setNumReduceTasks*().
2009/3/2 Rasit OZDAS <rasitoz...@gmail.com> > Hi! > > Whatever code I run on hadoop, reduce starts a few seconds after map > finishes. > And worse, when I run 10 jobs parallely (using threads and sending one > after > another) > all maps finish sequentially, then after 8-10 seconds reduces start. > I use reducer also as combiner, my cluster has 6 machines, namenode and > jobtracker run also as slaves. > There were 44 maps and 6 reduces in the last example, I never tried a > bigger > job. > > What can the problem be? I've read somewhere that this is not the normal > behaviour. > Replication factor is 3. > Thank you in advance for any pointers. > > Rasit > -- http://daily.appspot.com/food/
