Re: Planner problems in 8.2.4 and 8.2.5 (was: Possible planner bug/regression introduced in 8.2.5) - Mailing list pgsql-bugs

I wrote:
>> This might be a bug in the LIKE estimator (if so, it's in 8.2.3 as
>> well).  I don't have time to look closer right now, but can you show us
>> the pg_stats row for orders_smaller.order_number?

> Oh, never mind that ... on inspection, the NOT LIKE selectivity
> estimator is obviously broken: patternsel() doesn't realize it needs
> to negate the results of the operator when applying same to histogram
> entries.

I've applied a patch that should make this better:
http://archives.postgresql.org/pgsql-committers/2007-11/msg00101.php

            regards, tom lane