Hi You need to alter the value of mapred.max.split size to a value larger than your block size to have less number of map tasks than the default.
On Tue, Oct 2, 2012 at 10:04 PM, Shing Hing Man <mat...@yahoo.com> wrote: > > > > I am running Hadoop 1.0.3 in Pseudo distributed mode. > When I submit a map/reduce job to process a file of size about 16 GB, in > job.xml, I have the following > > > mapred.map.tasks =242 > mapred.min.split.size =0 > dfs.block.size = 67108864 > > > I would like to reduce mapred.map.tasks to see if it improves > performance. > I have tried doubling the size of dfs.block.size. But > the mapred.map.tasks remains unchanged. > Is there a way to reduce mapred.map.tasks ? > > > Thanks in advance for any assistance ! > Shing > >
