Re: Indexes not always used after inserts/updates/vacuum

Reinhard Max <max@suse.de>

From: Reinhard Max <max@suse.de>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: "Michael G. Martin" <michael@vpmonline.com>, <pgsql-bugs@postgresql.org>
Date: 2002-02-28T15:00:47Z
Lists: pgsql-bugs

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On Thu, 28 Feb 2002 at 09:51, Tom Lane wrote:

> Reinhard Max <max@suse.de> writes:
> > I've just found a case where forcing indexscans results in much higher
> > speed.
>
> >         ->  Index Scan using foo_pkey on foo
> > 		(cost=0.00..25153.18 rows=352072 width=4)
> > 		(actual time=0.03..157.57 rows=38432 loops=1)
>
> The major estimation error is evidently in this indexscan.  What
> statistics does pg_stats show for this table?

See attached file.

BTW, I've just done the same test on PostgreSQL 7.1 and got similar
results.

cu
	Reinhard