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

> 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.

I have to respectfully disagree. Even something similar to the script were part of your normal system activity, the hit ratio is still meaningful. But it is about as uncommon as gauging mpg with a fast leaking gas tank.

>
> 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'.
>

Nevertheless cache hit ratio is still the primary indicator of buffer usage. Otherwise, we would just ignore the buffer size and keep running the script for performance improvement. Received on Thu Oct 03 2002 - 14:24:23 CDT