On 18 September 2011 20:45, Stefan Keller <sfkeller@gmail.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
