Re: varchar does not work too well with IS NOT NULL partial indexes.

"Dawid Kuroczko" <qnex42(at)gmail(dot)com> writes:

> Now, if we:
>
> # EXPLAIN ANALYZE SELECT t FROM foo WHERE t='X17';
> QUERY PLAN
> ---------------------------------------------------------------------------------------------------
> Seq Scan on foo (cost=0.00..18025.78 rows=1 width=8) (actual
> time=0.079..565.661 rows=1 loops=1)
> Filter: ((t)::text = 'X17'::text)
> Total runtime: 565.689 ms
>
>
> # EXPLAIN ANALYZE SELECT t FROM foo WHERE t='X17';
> QUERY PLAN
> -------------------------------------------------------
> Seq Scan on foo (cost=0.00..178.00 rows=50 width=68)
> Filter: ((t)::text = 'X17'::text)
> (2 rows)

I still think you're playing games with the output. a) This is not an EXPLAIN
ANALYZE at all, there are no "actual" values. And b) there's no explanation
for why the estimates should be different for this query than the previous,
identical, query.

Send along the actual psql session, not an edited version.

--
Gregory Stark
EnterpriseDB http://www.enterprisedb.com