Re: <= Index.

pgsql-admin-owner(at)postgresql(dot)org wrote on 31/03/2002 08:06:52:

> Greg Sikorski writes:
>
> > How come this Index isn't being used in the situation below?
>
> There's no point in using an index if you're retrieving nearly the
entire
> table.
>
> --
> Peter Eisentraut peter_e(at)gmx(dot)net
>
>

Well, that was probably a poor example to include, but it was nearly 4am
;)

Typically <20 results are returned, although it still says "Seq Scan", but
on a smaller subset.

--
cmaster=# SELECT user_id,channel_id FROM levels WHERE suspend_expires <=
1017589362 AND suspend_expires <> 0;
user_id | channel_id
---------+------------
...
(17 rows)

cmaster=# explain analyze SELECT user_id,channel_id FROM levels WHERE
suspend_expires <= 1017589362 AND suspend_expires <> 0;
NOTICE: QUERY PLAN:

Seq Scan on levels (cost=0.00..13709.09 rows=2609 width=8) (actual
time=208.98..1521.08 rows=17 loops=1)
Total runtime: 1521.29 msec

Cheers, Greg.