Oracle FAQ Your Portal to the Oracle Knowledge Grid
HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US
 

Home -> Community -> Usenet -> c.d.o.server -> Re: Analyze Table Compute Statistics but slowed down performance ??

Re: Analyze Table Compute Statistics but slowed down performance ??

From: Jonathan Gennick <jonathan_at_gennick.com>
Date: 2000/06/02
Message-ID: <cp9ejssvr7vj86uioreem24nuq5ei9k3c8@4ax.com>#1/1

On Thu, 01 Jun 2000 22:01:18 +0800, Raymond <kudoshizuka_at_hotmail.com> wrote:

>After one week, I have
>(5) performed the command "Analyze table ... compute statistics;" for
>all the tables in the database. The optimizer_mode is CHOOSE.
>However, the same posting job as point (4) ran for almost 6 hours to
>complete! It caused the system slowed down dramatically.

If you did not have statistics before, than computing statistics causes Oracle to use the cost-based optimizer rather than the rule-based optimizer. This is not always good, as you have discovered. Try changing your optimizer_mode to RULE, and see if that makes a difference.

Hmmm... Be careful changing the mode globally. If you have apps designed for the cost-based optimizer, you could cause problems with those. Try to think of a relatively safe way to test this.

Jonathan



jonathan_at_gennick.com
http://gennick.com
Brighten the Corner Where You Are Received on Fri Jun 02 2000 - 00:00:00 CDT

Original text of this message

HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US