Hi ,

I need to detect the straggler map tasks specifically the last one to do
some experiments .As i undestood job tracker is aware of all map tasks ,so
is there any way to know the current  running map task is the
last(straggler)  one  ?
Samaneh

Yes, you should look at JobInProgress class, and search for 'speculative'. JobTracker already has logic to launch speculative copies for tasks which are progressing at a degraded rate relative to other tasks.

HTH,
+Vinod Kumar Vavilapalli
Hortonworks Inc.
http://hortonworks.com/

On Nov 25, 2012, at 2:18 PM, Samaneh Shokuhi wrote:

> Hi ,
>
> I need to detect the straggler map tasks specifically the last one to do
> some experiments .As i undestood job tracker is aware of all map tasks ,so
> is there any way to know the current  running map task is the
> last(straggler)  one  ?
>
>
> Samaneh