Re: Two indexes on same column

On Wed, Jul 20, 2011 at 2:39 PM, Vlastimil Krejcir <krejcir(at)ics(dot)muni(dot)cz>wrote:

> Hi,
>
> what index is used (and according to what rules) when there are two (or
> more) different indexes defined on one column? Assume:
>
> CREATE TABLE example (
> id SERIAL PRIMARY KEY,
> ...);
> CREATE INDEX example_id_idx ON example USING hash (id);
>
> By default there are btree index created and the hash index is then
> created. So there are two indexes on column "id". Are there described
> somewhere what index is used and when? Does it depend on query analyzer and
> planner?
>
> Thanks
>
>
You are right, depends on the optimizer and query to which index to choose.
EXPLAIN command on the query will give you the optimizer path.

---
Regards,
Raghavendra
EnterpriseDB Corporation
Blog: http://raghavt.blogspot.com/