Re: bitmap indexes - performance

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От Bruce Momjian
Тема Re: bitmap indexes - performance
Дата
Msg-id 201007020131.o621VWK08371@momjian.us
обсуждение исходный текст
Ответ на Re: bitmap indexes - performance  (Leonardo F <m_lists@yahoo.it>)
Ответы Re: bitmap indexes - performance  (Mark Kirkwood <mark.kirkwood@catalyst.net.nz>)
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Leonardo F wrote:
> I'm trying to find more docs that explain the "improvements" of
> bitmap indexes in other products... but most of what I've found
> talks about bitmapAND/OR.... which is something that is very
> cool, but that postgres already does even with btree indexes...
> or index creation time/size, which are, for the moment, the only
> things that I'm pretty confident the patch would actually provide.

I think a real limitation of on-disk bitmap indexes is that they are
only feable for low cardinality columns, while btree handles all column
types.

--  Bruce Momjian  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com
 + None of us is going to be here forever. +


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