Re: Slow execution time when querying view with WHERE clause

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>
To: Mike Mascari <mascarm@mascari.com>
Cc: pgsql-performance@postgresql.org
Date: 2004-11-23T17:54:05Z
Lists: pgsql-performance
Mike Mascari <mascarm@mascari.com> writes:
> When I query the view with a simple filter, I get:

> explain analyze select * from p_areas where deactive is null;

The problem seems to be here:

>     ->  Seq Scan on _areas a  (cost=0.00..2.48 rows=1 width=163) (actual time=0.037..0.804 rows=48 loops=1)
>           Filter: (deactive IS NULL)

Why is it so completely off about the selectivity of the IS NULL clause?
Are you sure you ANALYZEd this table recently?

			regards, tom lane