How to decide number of mappers?

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While running a mapreduce job in Hadoop, how to decide how many mappers are needed?

Jan 30 in Big Data Hadoop by Raksha
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1 answer to this question.

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The number of mapper depends on the total size of the input. i.e. the total number of blocks of the input files.

Mapper= {(total data size)/ (input split size)}

If data size= 1 Tb and input split size= 100 MB

Then, Mapper= (1000*1000)/100= 10,000

answered Jan 30 by Omkar
• 67,660 points

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