On Mon, Aug 08, 2011 at 12:51:40PM -0400, Tom Lane wrote:
> hubert depesz lubaczewski <depesz@xxxxxxxxxx> writes:
> > and we have a query:
> > select count(*) from objects where state='active'::text and ending_tsz <= ( select now() - '1 day'::interval );
>
> Try getting rid of the sub-select. There might have been a reason to do
> it like that ten years ago, but these days it's a guaranteed
> pessimization.
looks like even worse plan:
QUERY PLAN
-------------------------------------------------------------------------------------------------------------------
Aggregate (cost=9168023.89..9168023.90 rows=1 width=0)
-> Bitmap Heap Scan on objects (cost=336429.41..9147670.19 rows=8141478 width=0)
Recheck Cond: (state = 'active'::text)
Filter: (ending_tsz <= (now() - '1 day'::interval))
-> Bitmap Index Scan on objects_stat_user_id_creation_tsz (cost=0.00..334394.04 rows=10064868 width=0)
Index Cond: (state = 'active'::text)
(6 rows)
Best regards,
depesz
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