| From: | Bruce Momjian <bruce(at)momjian(dot)us> |
|---|---|
| To: | Leonardo F <m_lists(at)yahoo(dot)it> |
| Cc: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Robert Haas <robertmhaas(at)gmail(dot)com>, pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: bitmap indexes - performance |
| Date: | 2010-07-02 01:31:32 |
| Message-ID: | 201007020131.o621VWK08371@momjian.us |
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| Lists: | pgsql-hackers |
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(at)momjian(dot)us> http://momjian.us
EnterpriseDB http://enterprisedb.com
+ None of us is going to be here forever. +
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