Re: Does anybody really use Oracle 8i on Win2k?

"tingl" <tlam15_at_hotmail.com> wrote in message news:f487699f.0210020828.57a3279d_at_posting.google.com... [Snip]
> I agree but we don't know what type of applications are being run
> against this database. If the cache hit is too low, even pure data
> warehouse can benefit from some extra memory.

Please don't tune by hit ratios!!!!

They are largely meaningless, as a quick trip to Connor's site (www.oracledba.co.uk) and the 'Tuning' link will show you: he has a very nice script there, under the "Custom Hit Ratio" link, which lets you dial your own hit ratio. Fancy 97%.... Lo! it shall be so. 98.5% anyone?? Go for it: the script makes it so.

Any ratio you fancy, and without a single bit of extra memory being allocated to the Buffer Cache? The only proper conclusion is that the hit ratio is a profoundly meaningless tuning goal. Used cautiously, it *may* be a reasonable clue as to performance problems, but its not an end in itself, and a low ratio definitely doesn't mean 'bung in some extra memory'.

Regards
HJR
>Whether you need this
> extra memory depends completely on your particular system. I am simply
> pointing out a limitation which should be taken into consideration.
Received on Wed Oct 02 2002 - 15:38:35 CDT