Re: index on timestamp performance

On Wed, 29 Jan 2003, Eric Cholet wrote:

> I have this schema:
>
>
>  motid  | integer                     | not null
>  objid  | integer                     | not null
>  date   | timestamp without time zone | not null
> Indexes: dico_frs_motid_date btree (motid, date)
>          dico_frs_objid btree (objid)
>
> The performance I'm getting from the index that contains
> 'date' is much slower than when using the objid index
> (different queries of course). This is a 10 million row
> table. Am I right to assume that postgres needs to do
> more work because it has to convert the dates to some
> internal (integer?) format?

What does explain (analyze if possible) show for the two queries?
It could just be a difference in plans or estimates.