Re: Slow Query- Bad Row Estimate - Mailing list pgsql-performance

From Ozer, Pam
Subject Re: Slow Query- Bad Row Estimate
Date
Msg-id 216FFB77CBFAEE4B8EE4DF0A939FF1D1018359@mail-001.corp.automotive.com
Whole thread Raw
In response to Re: Slow Query- Bad Row Estimate  (Josh Berkus <josh@agliodbs.com>)
Responses Re: Slow Query- Bad Row Estimate
List pgsql-performance
I had just analyzed the dealergroupgeochache table. Wow.  Thank you. That did the trick. Can you give me an explanation
ofthe default_stats work?  I don't think I completely understand what it means when you set it to 500 instead of 1000?
 

thanks
-----Original Message-----
From: pgsql-performance-owner@postgresql.org [mailto:pgsql-performance-owner@postgresql.org] On Behalf Of Josh Berkus
Sent: Friday, October 29, 2010 2:10 PM
To: pgsql-performance@postgresql.org
Subject: Re: [PERFORM] Slow Query- Bad Row Estimate

On 10/29/10 1:54 PM, Ozer, Pam wrote:
> "                    ->  Index Scan using dealergroupgeocache_i01 on
> dealergroupgeocache  (cost=0.00..5719.56 rows=9055 width=10) (actual
> time=0.015..87.689 rows=163491 loops=1)"

This appears to be your problem here.

a) when was dealergroupgeocache last ANALYZED?

b) try increasing the stats_target on dealergroupid and regionid, to say
500 and re-analyzing.

-- 
                                  -- Josh Berkus
                                     PostgreSQL Experts Inc.
                                     http://www.pgexperts.com

-- 
Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-performance

pgsql-performance by date:

Previous
From: "Ozer, Pam"
Date:
Subject: Re: Slow Query- Bad Row Estimate
Next
From: Tom Lane
Date:
Subject: Re: Slow Query- Bad Row Estimate