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From Lars George <lars.geo...@gmail.com>
Subject Re: Newbie question about scan filters
Date Mon, 06 Dec 2010 11:12:34 GMT
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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