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From ramkrishna vasudevan <ramkrishna.s.vasude...@gmail.com>
Subject Re: the scan will be executed parallel if not use coprocessor?
Date Mon, 15 Jul 2013 04:15:39 GMT
The HBase by default does not use parallel scanning mechanism.  It is
sequential.  There are some JIRA that try to implement scanning in parallel
on the regions.  HBASE-1935 is one such idea.
Projects like phoenix uses Coprocessors to scan the regions in parallel and
the results are returned to the clients.

Regards
Ram


On Mon, Jul 15, 2013 at 7:20 AM, ch huang <justlooks@gmail.com> wrote:

> phoenix is using coprocessor internal
>
> On Sun, Jul 14, 2013 at 11:15 PM, Asaf Mesika <asaf.mesika@gmail.com>
> wrote:
>
> > To my knowledge, scan is not parallel, hence the speed of queries of
> > Impala, Phoenix, and other similar projects.
> >
> > On Saturday, July 13, 2013, ch huang wrote:
> >
> > > hi ted ,for example i have a table with 10 regions, if i offer the
> > > condition hit the data of 8 regions,is it different do it use oraginal
> > scan
> > > and use coprocessor? i know coprocessor can do it parallel for each
> > region
> > > ,but why the oraginal scan will slow than coprocessor?
> > >
> > >
> > >
> > > On Sat, Jul 13, 2013 at 7:36 PM, Ted Yu <yuzhihong@gmail.com
> > <javascript:;>>
> > > wrote:
> > >
> > > > Can you clarify your question a little bit ?
> > > >
> > > > That is, are you expecting parallel scan within region boundary or
> > across
> > > > boundaries ?
> > > >
> > > > Cheers
> > > >
> > > > On Jul 13, 2013, at 1:43 AM, ch huang <justlooks@gmail.com
> > <javascript:;>>
> > > wrote:
> > > >
> > > > > ATT
> > > >
> > >
> >
> >
> > --
> > Sent from Gmail Mobile
> >
>

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