I've been trying out the new hased subselect code from CVS. It appears
that the planner isn't taking the distinctiveness of the values from the
subselect into account:
bbaetz=# explain analyze select count(*) FROM bugs where product_id IN
(SELECT product_id FROM bugs);
QUERY PLAN
---
On Sun, Jan 26, 2003 at 02:09:49PM -0500, Tom Lane wrote:
>
> This isn't really anything to do with the new IN code, but is a
> long-standing problem: cost_mergejoin doesn't apply any penalty factor
> for the case where there are lots of duplicates in both inner and outer
> relation (causing resca
On Sun, Jan 26, 2003 at 06:51:18PM -0500, Tom Lane wrote:
> Bradley Baetz <[EMAIL PROTECTED]> writes:
> > On Sun, Jan 26, 2003 at 02:09:49PM -0500, Tom Lane wrote:
> >> This isn't really anything to do with the new IN code, but is a
> >> long-standing pro
On Sun, Jan 26, 2003 at 09:43:18PM -0500, Tom Lane wrote:
> We're already checking that as a separate plan alternative. The
> implementation could be improved a little, though --- we could combine
> the uniq-ification into the Hash node.
Right, or skip it entirely when selecting stuff with uniqu
On Sun, Jan 26, 2003 at 11:18:31PM -0500, Tom Lane wrote:
> Bradley Baetz <[EMAIL PROTECTED]> writes:
> > Right, or skip it entirely when selecting stuff with unique constraints.
>
> I'm hesitant to do that until we have some scheme in place for
> invalidating cac
