Hadoop

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- September 20, 2018 at 3:13 pm #5454
  
  DataFlair Team
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  We have a 400MB file containing single line of data and the HDFS block size is 128MB. How many mappers do we need to read the file?
- September 20, 2018 at 3:13 pm #5455
  
  DataFlair Team
  Spectator
  
  You can calculate the No. of Mappers using the following reference.
  
  No. of mappers = total size of the file/ input split size
  
  For example, if the total size of input is 1 GB and input split size is set to 128 MB then:
  No. of mappers = 1 x 1024 / 128 = 8 mappers.
  
  In you case, No. of Mappers = 400/128 => 4
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