Oracle FAQ Your Portal to the Oracle Knowledge Grid

Home -> Community -> Mailing Lists -> Oracle-L -> RE: optimizer_index_cost_adj and optimizer_index_caching

RE: optimizer_index_cost_adj and optimizer_index_caching

From: Wolfgang Breitling <>
Date: Fri, 05 Mar 2004 09:58:56 -0700
Message-Id: <>

I already said in an earlier post (possibly on a different subject) that I am biased against changing O_I_C and particularly O_I_C_A, especially in light that it has gained almost silver bullet status. Every post in a metalink forum or on c.d.o.s about performance of a sql gets at least one response suggesting lowering O_I_C_A as a solution. For me it is just another flavour of the folly that views all FTS as evil and index access as good.
OK, I step down from the soap box. I do not have experience with Oracle 9 in a production environment, so I have not had a chance to test it for real, but Joze Senegacnik ( seems to have had several clients with Oracle 9 and reports good experience with it.

As for "blowing up in ones face", if you think system_stats may be dynamite, I would consider O_I_C_A<100 nitroglycerine.

At 08:55 AM 3/5/2004, you wrote:
>Hi wolfgang
>I actually asked dan fink about this at UKOUG, because I haven't seen any
>investigations into system stats anywhere, do you have some evidence,
>links etc looking into the use of system stats anywhere? It instinctively
>sounds a good idea to me, but one that has the capability of blowing up in
>ones face. I don;'t like explosions much - I do like trying to do things
>the right way.
>Niall Litchfield
>Oracle DBA
>Audit Commission
>+44 117 975 7805
> > -----Original Message-----
> > From:
> > Sent: 05 March 2004 15:04
> > To:;
> > Subject: Re: optimizer_index_cost_adj and optimizer_index_caching
> >
> >
> > If you are using Oracle 9, forget about O_I_C_A and O_I_C
> > (i.e. leave them
> > at their default) and use dbms_stats.gather_system_stats
> >
> > My 0.014938 cents (Canadian currency)
> >

Wolfgang Breitling
Oracle7, 8, 8i, 9i OCP DBA
Centrex Consulting Corporation

Please see the official ORACLE-L FAQ:

To unsubscribe send email to: put 'unsubscribe' in the subject line.
Archives are at
FAQ is at
Received on Fri Mar 05 2004 - 11:17:09 CST

Original text of this message