CODEWITHSUNDEEP
javahadoopmapreducebigdata
DEEPAK YADAV
DEEPAK YADAV

Reputation: 47

HADOOP - number of output files produced as mapper output

i want to know how many files will be produced if only a single mapper ( no reducer,no combiner etc ) is run for all file splits .

example- if there are 4 file splits . then there is single mapper that will process all file splits. how many files as mapper output ?? -> one or four

Upvotes: 1

Views: 475

Answers (1)

brandon.bell
brandon.bell

Reputation: 1411

Each map task will produce one output file. If you have one file on HDFS that is split into four blocks, you will get four output files from a Map-Only job. If the input file is not in a splittable format, like GZip, it will be combined and only one mapper will act on it, outputting one file.

Upvotes: 4

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