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Posted to common-user@hadoop.apache.org by Steve Lewis <lo...@gmail.com> on 2010/11/04 21:28:58 UTC

Is there any reliable way for a reducer to determine the number of mappers used in a job

Short of having every mapper increment a counter

-- 
Steven M. Lewis PhD
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Re: Is there any reliable way for a reducer to determine the number of mappers used in a job

Posted by Harsh J <qw...@gmail.com>.

Hello,

On Fri, Nov 5, 2010 at 1:58 AM, Steve Lewis <lo...@gmail.com> wrote:
> Short of having every mapper increment a counter

Sure, since "mapred.map.tasks" is computed and set before jobs are
'submitted' for running (before setup itself), it can be read via the
Configuration object in the Reducer's context.

-- 
Harsh J
www.harshj.com