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From Jeff Kolesky <j...@opower.com>
Subject Re: Does HBase supports parallel table scan if I use MapReduce
Date Tue, 20 Aug 2013 16:02:44 GMT
The scan will be broken up into multiple map tasks, each of which will run
over a single split of the table (look at TableInputFormat to see how it is
done).  The map tasks will run in parallel.


On Tue, Aug 20, 2013 at 8:45 AM, yonghu <yongyong313@gmail.com> wrote:

> Hello,
> I know if I use default scan api, HBase scans table in a serial manner, as
> it needs to guarantee the order of the returned tuples. My question is if I
> use MapReduce to read the HBase table, and directly output the results in
> HDFS, not returned back to client. The HBase scan is still in a serial
> manner or in this situation it can run a parallel scan.
> Thanks!
> Yong

*Jeff Kolesky*
Chief Software Architect

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