Oracle-L: RE: Oracle, Siebel and rule-based optimization

From: Cunningham, Gerald <Gerald.Cunningham_at_usi.net>
Date: Thu, 30 Jan 2003 11:20:07 -0800
Message-ID: <F001.0053F592.20030130112007@fatcity.com>

Hi there,

We run quite a bit of Siebel here, against everything from 7.3.4 to 8.1.7. They all run rule-based. We have set optimizer mode to CHOOSE and analyzed tables in the past - performance got dramatically worse!

You can probably get some individual statements to run better cost-based, but the app as a whole does run better rule based.

One thing to watch out for - Siebel creates all objects using default storage clauses ("to save space" I was told by a Siebel consultant, since there are typically hundreds of unused tables). Go with LMT to be safe. I learned the hard way, with a database that contained more than 2 MILLION extents. Had to rebuild with LMT... even coalescing a TS took days... (learned some internal stuff tho')

Jerry

-----Original Message-----
Sent: Thursday, January 30, 2003 12:51 PM To: Multiple recipients of list ORACLE-L

Michael:

	Would you please post a summary of findings here on the list?  I
	too have a Siebel implementation going on, and we are 
	experiencing performance issues, and have set all the 
	Siebel-specified initSID.ora parameters.
	 
	I am in California, and the database is 'across the pond' in 
	Europe, so I am doing this remotely, and about 8 hours out of 
	phase with my users.  Any knowledge transfer will be

appreciated.

	Thanks
	Mike
	 

		-----Original Message-----
		From: Michael Fontana [mailto:mfontana_at_verio.net]
		Sent: Thursday, January 30, 2003 7:41 AM
		To: Multiple recipients of list ORACLE-L
		Subject: Oracle, Siebel and rule-based optimization
		
		


		I would like to ask a question of this esteemed and
knowledgeable audience about running
		SIEBEL applications on Oracle.  Siebel insists that
their CRM application will only run with
		acceptable performance if rule-based optimization is
chosen, yet, as we all know, there are
		documented examples of poor performance, and strong

recommendations to the contrary from Oracle.

At one point, I recall reading an article from a knowledgeable consultant describing what must be done

to get Siebel to run with optimizer_mode=choose. Any assistance in reaching this goal, or comments,

would be more than appreciated. We're still in the implementation phase, and are already receiving

poor performance on certain processes, even using the recommended rule based optimization. I

predict it will only get worse!

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Author: Cunningham, Gerald
INET: Gerald.Cunningham_at_usi.net

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