Re: Query w empty result set with LIMIT orders of magnitude slower than without

"Frank Joerdens" <frank@joerdens.de> writes:
> It seems to me that the planner makes a very poor decision with this
> particular query:

Try increasing the stats on woouser.  You need it to make a smaller
estimate of the number of matching rows here:

>                ->  Index Scan Backward using webapp_invite_pkey on
> webapp_invite  (cost=0.00..201698.51 rows=382 width=44) (actual
> time=2545.131..2545.131 rows=0 loops=1)
>                      Filter: ((woouser)::text = 'suggus'::text)

            regards, tom lane