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From Arun C Murthy <...@yahoo-inc.com>
Subject Re: phases in tasks
Date Thu, 24 Mar 2011 18:42:51 GMT

On Mar 24, 2011, at 11:37 AM, Pedro Costa wrote:

> Hi,
>
> 1 - A Task is composed by several phases:
> STARTING, MAP/REDUCE, SHUFFLE, SORT, CLEANUP.
>

Right. These are 'phases' for a map and/or reduce task after it starts  
running.

> A JobTracker and a TaskTracker also has phases?
>
> 2 - It exists also the following phases
> RUNNING,
> 		SUCCEEDED,
> 		FAILED,
> 		UNASSIGNED,
> 		KILLED,
> 		COMMIT_PENDING,
> 		FAILED_UNCLEAN,
> 		KILLED_UNCLEAN,
>
> These phases also belong to the Map or Reduce tasks. So, it exists two
> group of phases. Why is that?
>

These are 'states' for either map or reduce tasks, starting from their  
creation.

Hope that helps.

Arun

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