Re: help with getting index scan - Mailing list pgsql-general

From Thomas T. Thai
Subject Re: help with getting index scan
Date
Msg-id Pine.NEB.4.43.0202250943330.26810-100000@ns01.minnesota.com
Whole thread Raw
In response to Re: help with getting index scan  (Doug McNaught <doug@wireboard.com>)
List pgsql-general
On 25 Feb 2002, Doug McNaught wrote:

> > > Also, the estimate of rows returned from the phone_cat_address scan is
> > > pretty large--how large is the table itself?  Sequential scan is
> > > actually faster if you're going to end up returning most of the rows
> > > in the table...
> >
> > yellowpages=# select count(*) from phone_cat_address;
> >  count
> > --------
> >  336702
> > (1 row)
> >
> > type typical results should be a tiny fraction of that number.
>
> Well, EXPLAIN is indicating (unless I misread it) that the estimate of
> rows returned is 336702, so it's not surprising that it opts for a
> sequential scan.  Is this under 7.1 or 7.2?  The latter keeps much
> better statistics about table populations...

this is under 7.2. is there away to force it to use index scan? cause
right now when i'm searching using a cat reference, it's taking a few
seconds.

---
Thomas T. Thai | Minnesota.com | tom@minnesota.com | 612.220.6220
Visit http://www.minnesota.com/




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