Re: 8.4, One-Time Filter and subquery ( ... FROM function() union all ... ) - Mailing list pgsql-hackers

Sergey Burladyan <eshkinkot@gmail.com> writes:
> Oh, now problem with simple query:

> 8.4.0 from Debian
> explain analyze select i from t where i >= 10 and i = 1;
>                                      QUERY PLAN
> ------------------------------------------------------------------------------------
>  Result  (cost=0.00..0.01 rows=1 width=0) (actual time=0.002..0.002 rows=0 loops=1)
>    One-Time Filter: false
>  Total runtime: 0.030 ms

> CVS HEAD
> explain analyze select i from t where i >= 10 and i = 1;
>                                             QUERY PLAN
> ---------------------------------------------------------------------------------------------------
>  Seq Scan on t  (cost=0.00..17030.00 rows=1 width=4) (actual time=449.651..449.651 rows=0 loops=1)
>    Filter: ((i >= 10) AND (i = 1))
>  Total runtime: 449.726 ms

Hmm, that's got nothing to do with my recent patch, because there's no
appendrel anywhere.  Are you sure you are using the same
constraint_exclusion setting in both cases?
        regards, tom lane