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From 陈加俊 <cjjvict...@gmail.com>
Subject Re: Newbie question about scan filters
Date Mon, 06 Dec 2010 11:53:59 GMT
Hi Lars,

I just want to scan the table and find out the rows that the key value or
one column's value  belonged to the domain that i specified.

cheers,
jiajun

On Mon, Dec 6, 2010 at 7:12 PM, Lars George <lars.george@gmail.com> wrote:

> Hi Jiajun,
>
> Sure, why not? What are you trying to achieve?
>
> Lars
>
> On Mon, Dec 6, 2010 at 3:19 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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