| From: | Chris Jones <chris(at)mt(dot)sri(dot)com> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | ryan(at)paymentalliance(dot)net, pgsql-general(at)postgresql(dot)org |
| Subject: | Re: Re: Query not using index |
| Date: | 2001-05-10 21:34:18 |
| Message-ID: | 20010510153418.G26743@mt.sri.com |
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| Lists: | pgsql-general |
On Thu, May 10, 2001 at 05:22:07PM -0400, Tom Lane wrote:
> ryan(at)paymentalliance(dot)net writes:
> > No the query usually returns between 0 and 5 rows. Usually not zero -
> > most often 1.
>
> Ah. You must have a few values that are far more frequent (like tens of
> thousands of occurrences?) and these are throwing off the planner's
> statistics.
I had a similar situation, where I had a lot of rows with 0's in
them. Changing those to NULLs worked wonders. The planner (or
statistics gatherer, or something) apparently takes notice of the
distribution of non-NULL values.
Chris
--
chris(at)mt(dot)sri(dot)com -----------------------------------------------------
Chris Jones SRI International, Inc.
www.sri.com
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