Re: Index Scans become Seq Scans after VACUUM ANALYSE

mlw <markw@mohawksoft.com>

From: mlw <markw@mohawksoft.com>
To: Andrew Sullivan <andrew@libertyrms.info>
Cc: pgsql-hackers@postgresql.org
Date: 2002-04-17T21:10:30Z
Lists: pgsql-hackers
Andrew Sullivan wrote:

> > Now, given the choice of the two strategies on a table, both pretty
> > close to one another, the risk of poor performance for using the
> > index scan is minimal based on the statistics, but the risk of poor
> > performance for using the sequential scan is quite high on a large
> > table.
> 
> I thought that's what the various cost estimates were there to cover.
> If this is all you're saying, then the feature is already there.

The point is that if the index plan is < 20% more costly than the sequential
scan, it is probably less risky.