Hi there- Yes, there is an input split for each region of the source table of a MR job.
There is a blurb on that in the RefGuide... http://hbase.apache.org/book.html#splitter On 9/4/12 11:17 AM, "Ioakim Perros" <imper...@gmail.com> wrote: >Hello, > >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, >Ioakim >
