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Posted to mapreduce-user@hadoop.apache.org by Geoffry Roberts <ge...@gmail.com> on 2011/05/20 18:18:19 UTC

Question About Using a Single Reducer

All,

I have a job where there I need to have but a single reducer.

i.e.
job.setNumReduceTasks(1);

When I do this, I get no log file for the reducer; mappers yes, but reducer
no.  If I remove the aforementioned statement, hadoop will spawn the
appropriate number of reducers as per my configuration and log file output
will ensue.

Does anyone know anything about this?

Thanks.
-- 
Geoffry Roberts