| From: | Peter Geoghegan <peter(at)2ndquadrant(dot)com> |
|---|---|
| To: | Stefan Keller <sfkeller(at)gmail(dot)com> |
| Cc: | pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: What about implementing a bitmap index? Any use cases? |
| Date: | 2011-09-18 20:06:32 |
| Message-ID: | CAEYLb_WLD16UKraWEdgmtcR3oZRF9n=M4XaSUxG6-hL2TueU=A@mail.gmail.com |
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| Lists: | pgsql-performance |
On 18 September 2011 20:45, Stefan Keller <sfkeller(at)gmail(dot)com> wrote:
> Hi,
>
> I know there exist Bitmap Index Scan and Bitmap Heap Scan in Postgres.
> What about implementing a bitmap index for explicit use (CREATE INDEX ...)?
> Any use cases?
> Bitmap indexes work best on values with low cardinality (categorical
> data), would be efficient in space and ready for logic operations.
>
> Stefan
>
> P.S. Disclaimer (referring to my other thread about Hash): I'm not a
> btree opposer :-> I'm just evaluating index alternatives.
Search the pgsql-hackers archives to read about an unsuccessful
attempt to introduce on-disk bitmap indexes to Postgres.
--
Peter Geoghegan http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training and Services
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