Re: Tuning 9i Database - after migrating from 8i. -

From: Wolfgang Breitling <breitliw_at_centrexcc.com>
Date: Thu, 04 Mar 2004 12:23:56 -0700
Message-Id: <6.0.3.0.2.20040304121827.02c3b208@pop.centrexcc.com>

I have to admit that I am not a fan of changing them from their default values. In the databases I am, or have been, working with (Peoplesoft), changing them usually induces too many NL joins with disastrous consequences.

In Oracle 9i I would investigate the use of dbms_stats.gather_system_stats prior to attempting to tweak the O_I_C.. parameters. Joze Senegacnik reports good success with it. I myself do not have experience with 9i in a large enough production setting to say.

At 10:32 AM 3/4/2004, you wrote:

>I am trying to determine if setting the two spfile parameters
>"optimizer_index_caching" and "optimizer_index_cost_adj" to values of
>other than the default does actually enhance or degrade the SQL queries.
>
>So my questions are
>1. Do you set these parameters ??
>2. If you do what values work for you ??
>3. What do you do in a case where it works for most but not for all of
>your SQL??
>
>TIA.
>
>Yuval.

Wolfgang Breitling
Oracle7, 8, 8i, 9i OCP DBA
Centrex Consulting Corporation
http://www.centrexcc.com

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Received on Thu Mar 04 2004 - 13:49:05 CST