Re: Re: Query not using index

On Thu, May 10, 2001 at 05:22:07PM -0400, Tom Lane wrote:

> ryan@paymentalliance.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@mt.sri.com -----------------------------------------------------
Chris Jones                                    SRI International, Inc.
                                                           www.sri.com