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From Hari Sreekumar <hsreeku...@clickable.com>
Subject Re: Newbie question about scan filters
Date Mon, 06 Dec 2010 05:19:41 GMT
Hey Lars,

Thanks for the kind explanation. got it now..

cheers,
Hari

On Mon, Dec 6, 2010 at 7:49 AM, 陈加俊 <cjjvictory@gmail.com> wrote:

> Hi
>
> Do I can use the scan filter ? the HBase that we used is version 0.20.6.
>
> jiajun
>
> On Mon, Dec 6, 2010 at 2:05 AM, Lars George <lars.george@gmail.com> wrote:
>
> > Hi Hari,
> >
> > The filters are applied server side (aka predicate pushdown). If you
> > were to scan and skip you incur extra IO cost. Filters, as they are
> > implemented right now are simply skipping and therefore all they can
> > do is slightly improve a normal scan performance. In the future you
> > might get better performance as they are re-implemented as
> > Coprocessors. Also, depending on certain filter criteria we can
> > optimize scans by skipping entire store files (since we know it does
> > not certain keys or timestamp based values).
> >
> > Lars
> >
> > On Sun, Dec 5, 2010 at 6:39 PM, Hari Sreekumar <hsreekumar@clickable.com
> >
> > wrote:
> > > Hi
> > >
> > > What are the differences between using a scan filter and simpli
> > > scanning and then filtering using if conditions? Any particular
> > > gotchas you need to be careful about while using filters extensively?
> > >
> > > Hari
> > >
> >
>

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