RE: changing session parameters after logon trigger

Many thanks for answer Jared.
The problem is that Siebel suggestions are sometimes pretty irrational ***and*** their suggstions are not giving the expected (performance) results. If some parameter changes proposed from Siebel don't work, they (SBL) say "Ask your DBA for assistance".
Anyway, the solution of the problem was to set "optimizer_features_enable=8.1.7". After setting this parameter we got "parse time cpu=0.01 sec". The funny thing is that SBL is stating that SBL (version 7.7) ist "CBO ready", but they are forcing the CBO in any possible way to behaive just like RBO.

Once again thank you for your time and help.

Regards. Milen  

-----Original Message-----
From: Jared Still [mailto:jkstill_at_gmail.com] Sent: Tuesday, October 18, 2005 6:06 PM
To: makulev_at_gmx.net
Cc: oracle-l_at_freelists.org
Subject: Re: changing session parameters after logon trigger

On 10/13/05, Milen Kulev <makulev_at_gmx.net> wrote: ...
> alter session set optimizer_mode = first_rows_10;
> alter session set hash_join_enabled = false;
> alter session set "_optimizer_sortmerge_join_enabled" = false; alter
> session set "_optimizer_join_sel_sanity_check" = true;
>

...
>
> When I set "_optimizer_sortmerge_join_enabled" to TRUE AND
> optimizer_dynamic_sampling to 0, then I am getting 0.1 seconds elapsed
> time!
>

Regardless of your testing results or advice you get from this list, you should probably discuss this with Sieble, er, Oracle?, support.

As these are underscore parameters, Oracle doesn't directly support them, Siebel *should* be able to offer some guidance.

--
Jared Still
Certifiable Oracle DBA and Part Time Perl Evangelist

--
http://www.freelists.org/webpage/oracle-l