| From: | Michael Fuhr <mike(at)fuhr(dot)org> |
|---|---|
| To: | Josh Berkus <josh(at)agliodbs(dot)com> |
| Cc: | pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: Functionscan estimates |
| Date: | 2005-04-08 22:38:20 |
| Message-ID: | 20050408223820.GA17450@winnie.fuhr.org |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers pgsql-performance |
On Fri, Apr 08, 2005 at 03:15:50PM -0700, Josh Berkus wrote:
>
> I'm wondering if it might be useful to be able to add estimated selectivity to
> a function definition for purposes of query estimation. Currently function
> scans automatically return a flat default 1000 estimated rows. It seems
> like the DBA ought to be able to ALTER FUNCTION and give it a row estimate
> for planning purposes.
About a month ago I mentioned that I'd find that useful. In a
followup, Christopher Kings-Lynne brought up the idea of a GUC
variable that could give hints about the expected row count.
http://archives.postgresql.org/pgsql-hackers/2005-03/msg00146.php
http://archives.postgresql.org/pgsql-hackers/2005-03/msg00153.php
--
Michael Fuhr
http://www.fuhr.org/~mfuhr/
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