Re: optimizer_index_caching and optimizer_index_cost_adj deprecated by system stats?

On Mar 13, 4:12 pm, hpuxrac <johnbhur..._at_sbcglobal.net> wrote:
> On Mar 13, 3:59 pm, NetComrade <netcomradeNS..._at_bookexchange.net>
> wrote:
>
> > I was told that  these parameters are somehow replaced by system stats
> > in 10g and beyond?
>
> > I can't see how that would be.
>
> > Thanks,
> > Andrey
> > .......
> > We run Oracle 9iR2,10gR1/2, 10gRAC on RH4/RH5 and Solaris 10 (Sparc)
> > remove NSPAM to email
>
> Have you looked at what Tom Kyte and Jonathan Lewis have written about
> this area?  Not hard to find this info.
>
> My "reduced size" impression is that both of them are leery of making
> adjustments to those parameters ( which Tom used to strongly advocate
> at one time ) in a 10g environment ... depending on what you do
> regarding gathering system stats.

I am against modifying the parameters away from the defaults on any release. Jonathan has written about some of the side effects that are possible when you do change the parameters. We made the choice years ago to just tune the SQL with most database optimizer related parameters left as is. That way we have had less surprises when we upgraded.

HTH -- Mark D Powell -- Received on Thu Mar 13 2008 - 15:44:50 CDT