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From Chia-Hung Lin <>
Subject Re: Task distribution issue
Date Fri, 17 Dec 2010 15:23:12 GMT
Yes. My understanding is that HADOOP-815 concerns JobInProgress's
memory footprint issue; and HADOOP-600 has issues JobTracker lost
tracks of tasks in TaskTracker due to race condition. From the
discussion the root cause looks like relating to the way how
JobTracker communicate with TaskTracker; therefore, I was thinking
that HAMA can learn from Hadoop's previous experience.

Thanks for helping schedule task killing, re-attempting functions, etc. issues.


2010/12/16 Edward J. Yoon <>:
> Hi,
> According to my understanding, it looks like a refactoring issue to
> reduce the complexity and the memory footprint of master server by
> removing back-calls of TaskInProgress and map structures. Right?
> I think, that's a nice idea. But we didn't implement the task killing,
> re-attempting functions yet. So, I would propose to schedule it for
> 0.2.1 release.
> -Edward
> On Thu, Dec 16, 2010 at 12:55 PM, Lin Chia-Hung <> wrote:
>> When working on BSPPeer fault tolerance
>> (, I came across
>> another issue - the task distribution currently employed in HAMA is
>> done by GroomServer requesting tasks from BSPMaster, similar to one
>> used in Hadoop mapreduce. This strategy has discussion at
>> regarding to e.g
>> memory footprint, race condition, etc. Although this issue do not
>> directly relate to the BSPPeer fault tolerance, the strategy
>> (GroomServer requests tasks from BSPMaster) employed may have
>> potential issue e.g. task can not be reschedule to the node expected.
>> So I would like to know if there is any chance the HAMA task
>> distribution mechanism may work toward this direction (proactive task
>> assignment)?
>> Thanks
> --
> Best Regards, Edward J. Yoon

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