Re: Cache Hit Ratio from system views

On Sep 3, 2:23 am, Niall Litchfield <niall.litchfi..._at_gmail.com> wrote:
> On 18 Aug, 08:15, joel garry <joel-ga..._at_home.com> wrote:
>
> > I don't have any argument with the idea that response times meeting
> > business requirements is a, or even the most reasonable metric. But I
> > feel compelled to point out how common it is to not define those
> > requirements properly, so making an assumption that there are already
> > properly defined response time requirements is jumping ahead too far
> > in a performance methodology. And yet, by the time there is a
> > perceived problem, it is already too late.
>
> Bang on the money as usual Joel. It's the biggest single cause of
> frustration I have these days. I have found though on a case by case
> basis, even reactively I've been able to say first
>
> What exactly is it that is too slow? Can I come and see?
> and second
> I see that report took 12 hours last time, what would be a resonable
> target for us to work to? half that time maybe?

Here we have a Sept. 3 response to an Aug 18 post, and it isn't too slow. :-)

I suspect the real problem is that Bob isn't willing to admit that "disk I/O percentage" just doesn't mean anything useful. He seems to get that all parts of the system need to be included, and gets that problems need to be deconstructed, but doesn't get that some metrics that are entirely within the purview of Oracle are useless. It's not a matter of faith, as so many posts have demonstrated.

jg

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