RE: optimizer_index_cost_adj and optimizer_index_caching

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 (joze.senegacnik@xxxxxx) 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: breitliw@xxxxxxxxxxxxx
> Sent: 05 March 2004 15:04
> To: breitliw@xxxxxxxxxxxxx; oracle-l@xxxxxxxxxxxxx
> 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
http://www.centrexcc.com 


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