Re: Planner problems in 8.2.4 and 8.2.5 (was: Possible planner bug/regression introduced in 8.2.5)

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Greg Sabino Mullane <greg(at)turnstep(dot)com>
Cc: pgsql-bugs(at)postgresql(dot)org
Subject: Re: Planner problems in 8.2.4 and 8.2.5 (was: Possible planner bug/regression introduced in 8.2.5)
Date: 2007-11-06 21:29:47
Message-ID: 886.1194384587@sss.pgh.pa.us
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: 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.

regards, tom lane

In response to

Responses

Browse pgsql-bugs by date

  From Date Subject
Next Message Derek G 2007-11-07 01:29:11 BUG #3726: Unable to upgrade
Previous Message Tom Lane 2007-11-06 21:18:31 Re: Planner problems in 8.2.4 and 8.2.5 (was: Possible planner bug/regression introduced in 8.2.5)