Re: Clarification required: autovacuum and VACUUM command mode

Hi Kevin,

Thanks again for a quick response.

I am using a 3rd party application, which in turn using PostgreSQL DB. I
can not change/tune the SQL queries, performed by the 3rd party
application. Hence, the statistics generated by ANALYZE, is of no use to
me. That is the reason, I have planned not to run ANALYZE.

Regards, Narasimha Murthy
Cell +91 95814 98895, +91-94940 62794 | 040-2347 2025 (O) | x2025 (O)

-----Original Message-----
From: Kevin Grittner [mailto:Kevin(dot)Grittner(at)wicourts(dot)gov]
Sent: Friday, May 14, 2010 8:18 PM
To: Narasimha Murthy-VRFX87
Cc: pgsql-admin(at)postgresql(dot)org
Subject: RE: [ADMIN] Clarification required: autovacuum and VACUUM
command mode

"Narasimha Murthy-VRFX87" <VRFX87(at)motorola(dot)com> wrote:

> Another query: I do not want to run Analyze. However, auto-vacuum runs

> both both VACUUM and ANALYZE. I do not see any option to disable
> running ANALYZE during auto-vacuum. Is there any way to achive this?

Usually it's best to run ANALYZE more often than VACUUM, since the
statistics generated by ANALYZE are used to choose the most efficient
plan, and ANALYZE runs faster because it just takes a random sample of
rows. Out-of-date statistics are one of the most common causes of slow
queries. That's not to say there couldn't be some very unusual
circumstances under which it might make sense to disable ANALYZE, but
I'm highly skeptical.

Anyway, if you *really* want to shoot that fly off the end of your toe
(to stretch a metaphor), you could adjust the autovacuum settings
related to analyze to really high values.

-Kevin