Re: [Q] Optimizer_mode and performance?

Dear L

It has been established that estimate based on (test vary from one version to another and from platform to another, so it is best you try it youserlf) sample of 10 to 20 % ensures better performance than compute.

HTH Regards

Kresimir Fabijanic

• Original Message ----- From: "L" <leed_at_chele.cais.net> To: <oracle-l_at_fatcity.com>; <oracledba_at_quickdoc.co.uk> Sent: Saturday, December 02, 2000 6:55 AM Subject: [Q] Optimizer_mode and performance?

> We have ORACLE 7.3.4.4 on SUN SPARC Solaris 2.6. Our ORACLE database
> running third party application on it. Recently, due to data growing
> (2i.5GB data on data tablespace), user starting to compliant performance
> slow on some SQL statements. The "optimizer_mode" we use are "choose" and
> I "analyze" the schema every week use following statements:
>
>
> exec dbms_utility.analyze_schema('USER1', 'COMPUTE',NULL,NULL,'FOR ALL
> INDEXED COLUMNS');
> exec dbms_utility.analyze_schema('USER1', 'COMPUTE');
>
>
>
> I turn on "tkprof" to trace the third party application (we DON'T have
> source code). I found some SQL statements run quickly under "rule" mode.
> After I change database "optimizer_mode" to "rule", users complaint other
> SQL statements run very slow. I report this problem to third party
> company. The engineer continue said following:
>
> 1. Analyze schema (actually we did)
> 2. Buy high speed CPU and high speed Hard disk RAID.
>
> My questions are:
>
> 1. Does my "analyze" statements collect NOT enought information?
>
> 2. user better hardware to fix software problem is correct way?
>
> 3. any other suggestion?
>
> Thanks.
>
>
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Received on Fri Dec 01 2000 - 19:49:27 CST