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From Ioakim Perros <imper...@gmail.com>
Subject Reading in parallel from table's regions in MapReduce
Date Tue, 04 Sep 2012 15:17:06 GMT

I would be grateful if someone could shed a light to the following:

Each M/R map task is reading data from a separate region of a table.
 From the jobtracker 's GUI, at the map completion graph, I notice that 
although data read from mappers are different, they read data 
sequentially - like the table has a lock that permits only one mapper to 
read data from every region at a time.

Does this "lock" hypothesis make sense? Is there any way I could avoid 
this useless delay?

Thanks in advance and regards,

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