Re: Odd explain estimate

On Fri, Aug 01, 2003 at 08:16:12AM -0400, Andrew Sullivan wrote:
> On Thu, Jul 31, 2003 at 05:59:59PM -0500, Jim C. Nasby wrote:
> >
> > Well, if I don't do this it wants to seqscan a table that occupies 350k
> > pages, instead of pulling a couple thousand rows. I started running it
> > with the seqscan and it's already taken way longer than it does if I
> > disable seqscan.
>
> That was indeed the question.
>
> If it uses a seqscan when it ought not to do, then there's something
> wrong with the statistics, or you haven't vacuum analysed correctly,
> or your table needs vacuum full (is it really 350k pages, or is that
> mostly dead space?), &c. -- all the usual bad-seqscan candidates.
>
> enable_seqscan=off is probably not a good strategy for any moderately
> complicated query.  If the planner were perfect, of course, you'd
> never need it at all.

Set statistics on the ID colum to 1000, vacuum analyze, and it's good to
go now. Thanks for your help!
--
Jim C. Nasby, Database Consultant                  jim@nasby.net
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