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MapReduce, mail # user - Number of map tasks spawned

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Number of map tasks spawned
Praveen Sripati 2010-04-25, 10:58


The MapReduce tutorial specifies that

 >> The Hadoop Map/Reduce framework spawns one map task for each
InputSplit generated by the InputFormat for the job.

But, the mapred.map.tasks definition is

 >> The default number of map tasks per job. Ignored when
mapred.job.tracker is "local".

So, is the number of map tasks spawned based on the number of
InputSplits generated or based on the mapred.map.tasks value specified
in the configuration file?