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From Sugandha Naolekar <sugandha....@gmail.com>
Subject Mappers vs. Map tasks
Date Tue, 25 Feb 2014 05:57:08 GMT

As per the various articles I went through till date, the File(s) are split
in chunks/blocks. On the same note, would like to ask few things:

   1. No. of mappers are decided as: Total_File_Size/Max. Block Size. Thus,
   if the file is smaller than the block size, only one mapper will be
   invoked. Right?
   2. If yes, it means, the map() will be called only once. Right? In this
   case, if there are two datanodes with a replication factor as 1: only one
   datanode(mapper machine) will perform the task. Right?
   3. The map() function is called by all the datanodes/slaves right? If
   the no. of mappers are more than the no. of slaves, what happens?

Thanks & Regards,
Sugandha Naolekar

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