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MapReduce, mail # user - How to get mapper counters (or equivalents) in reducer


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How to get mapper counters (or equivalents) in reducer
Jianhui Zhang 2012-04-30, 19:02
Hi folks,

Version: Hadoop 0.20.205.

My reducer can be optimized if I can get a good estimate on how many
records are produced by the mappers, that is, if I can get the
MAP_OUTPUT_RECORDS counter (or its equivalent) in my reducer. However,
I tried and always got 0, guess the counters are not passed to the
reducer context.

Anybody has encountered the same requirement? And any pointers on that?

Appreciate your help.

Thanks,
James