| Oracle FAQ | Your Portal to the Oracle Knowledge Grid | |
 |
 | |||
| Oracle FAQ | Your Portal to the Oracle Knowledge Grid | |
|
| |||
Home -> Community -> Mailing Lists -> Oracle-L -> Re: Re: optimizer_index_cost_adj and optimizer_index_caching
If I correctly understand your post, what you are saying is that
the init.ora parms O_I_C_A and O_I_C were set on all your
databases because it helped a problem on two of them.
This is not generally considered a good practice, that is, making changes to a parameter with global implications without a specific reason for doing so, and the testing to back it up.
I once set these parameters on a database that houses an application of somewhat questionable design. It did help, but I was really only trying to fix a single query.
So, I put the shotgun back in the cabinet, pulled out the laser scalpal and created a histogram on a single column of a single table and solved the problem.
HTH Jared
"Juan Cachito Reyes Pacheco" <jreyes_at_dazasoftware.com>
Sent by: oracle-l-bounce_at_freelists.org
03/09/2004 12:25 PM
Please respond to oracle-l
To: <oracle-l_at_freelists.org>
cc:
Subject: Re: Re: optimizer_index_cost_adj and optimizer_index_caching
I asked and this how it happened
one database gave problem, then we found setting this parameters solved
this
problem, then we set
them ONLY in one database
after about one year other database had the same problem, after some
months
other,
then we decided to set it to all at once.
because the worload is between and oltp and a dss, we don't have to change
it.
That is why I suggest to set it, is better to have a more acurrate value
set
in the database. in 9.2 windows
----- Original Message -----
From: <ryan.gaffuri_at_cox.net>
To: <oracle-l_at_freelists.org>
Sent: Tuesday, March 09, 2004 9:36 AM
Subject: Re: Re: optimizer_index_cost_adj and optimizer_index_caching
> the debate on this topic is exactly why we need to keep this list going.
Thanks for all your help guys.
> >
> > From: "Juan Cachito Reyes Pacheco" <jreyes_at_dazasoftware.com>
> > Date: 2004/03/09 Tue AM 08:19:01 EST
> > To: <oracle-l_at_freelists.org>
> > Subject: Re: optimizer_index_cost_adj and optimizer_index_caching
> >
> > I'm using, because in a specific database a query gave trouble, and I
fixed
> > it setting this parameters. Curiously in other production databases
(more
> > than 15) similar to that, didn't gave that problem.
> > But we decided to set it any way.
> > I think is better to set them, even when in most situation there is
not
> > problems.
> > :)
> >
> > ----- Original Message -----
> > From: "Niall Litchfield" <n-litchfield_at_audit-commission.gov.uk>
> > To: <oracle-l_at_freelists.org>
> > Sent: Tuesday, March 09, 2004 5:01 AM
> > Subject: RE: optimizer_index_cost_adj and optimizer_index_caching
> >
> >
> > Thanks Joze and Wolfgang
> >
> > I'm in a position where gathering system stats seems to me to be the
Right
> > Thing (tm) to do, certainly an advance on setting parameters based on
> > guesses/measurements ahead of time. I hadn't until now seen any
indications
> > as to whether the feature worked as advertised or if in fact gathering
> > system stats introduced for example unexpected and unwanted plan
changes,
> > curious bugs etc etc. In fact I hadn't seen *any* feedback at all
which
made
> > me suspicious that anyone was actually using it - I guess folks recall
the
> > introduction of the CBO which was equally the right thing to do but..
> >
> > Niall Litchfield
> > Oracle DBA
> > Audit Commission
> > +44 117 975 7805
> >
> >
> >
> > **********************************************************************
> > This email contains information intended for
> > the addressee only. It may be confidential
> > and may be the subject of legal and/or
> > professional privilege. Any dissemination,
> > distribution, copyright or use of this
> > communication without prior permission of
> > the sender is strictly prohibited.
> > **********************************************************************
> >
> > ----------------------------------------------------------------
> > Please see the official ORACLE-L FAQ: http://www.orafaq.com
> > ----------------------------------------------------------------
> > To unsubscribe send email to: oracle-l-request_at_freelists.org
> > put 'unsubscribe' in the subject line.
> > --
> > Archives are at http://www.freelists.org/archives/oracle-l/
> > FAQ is at http://www.freelists.org/help/fom-serve/cache/1.html
> > -----------------------------------------------------------------
> >
> >
> > ----------------------------------------------------------------
> > Please see the official ORACLE-L FAQ: http://www.orafaq.com
> > ----------------------------------------------------------------
> > To unsubscribe send email to: oracle-l-request_at_freelists.org
> > put 'unsubscribe' in the subject line.
> > --
> > Archives are at http://www.freelists.org/archives/oracle-l/
> > FAQ is at http://www.freelists.org/help/fom-serve/cache/1.html
> > -----------------------------------------------------------------
> >
>> Please see the official ORACLE-L FAQ: http://www.orafaq.com
> ----------------------------------------------------------------
-- Archives are at http://www.freelists.org/archives/oracle-l/ FAQ is at http://www.freelists.org/help/fom-serve/cache/1.html ----------------------------------------------------------------- ---------------------------------------------------------------- Please see the official ORACLE-L FAQ: http://www.orafaq.com ---------------------------------------------------------------- To unsubscribe send email to: oracle-l-request_at_freelists.org put 'unsubscribe' in the subject line. -- Archives are at http://www.freelists.org/archives/oracle-l/ FAQ is at http://www.freelists.org/help/fom-serve/cache/1.html -----------------------------------------------------------------Received on Tue Mar 09 2004 - 23:11:55 CST
 |
 |