Oracle FAQ Your Portal to the Oracle Knowledge Grid
HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US
 

Home -> Community -> Usenet -> c.d.o.server -> Re: Does anybody really use Oracle 8i on Win2k?

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

From: tingl <tlam15_at_hotmail.com>
Date: 7 Oct 2002 10:01:04 -0700
Message-ID: <f487699f.0210070901.12f6a24c@posting.google.com>


> > > > Then I guess hit ratio is not meaningless.
> > > >
> > >
> > > I said it was "largely" meaningless, and that you shouldn't "tune" by
> it, as
> > > its subject to a lot of 'fuzzy' factors.
> > >
> >
> > It is either meaningful or meaningless.
>
> So you say. It's not what I wrote. Nor is your statement true.
>
> >Everything is subject to many
> > factors including SQL tunning. We could look at this from an opposite
> > point of view. If the performance is poor, one should not just rely on
> > SQL tuning either. It is also subject to buffer size, but I would not
> > say SQL tuning should be ignored or even largely meaningless because
> > of that.
>
> And neither would I say that SQL tuning was largely meaningless. So don't
> put words into my mouth, please: it's called a strawman argument.
>

I think you are getting a little sensitive here. I am simply saying that if you cannot say sql tunning is meaningless, the same cannot be said about buffer size. That's it.

> > > It's *an* indicator. But (and here's the point you inisist on missing)
> it's
> > > a pretty *poor* indicator when it needs to be interpreted so heavily.
> > >
> >
> > Like I said before, I do not consider it a poor indicator in most
> > cases.
>
> Well, you are free to carry on in your beliefs and considerations. The fact
> that you're wrong shouldn't stop you in any way.
>
> >I cannot recall how many times the performance was insatantly
> > improved by simply looking at this number and adjusting the buffer
> > size.
> >
>
> Uh huh. The Niemich school of performance tuning. Seen it many times.
>

If I am seeing result, I don't think I care what school it is.

> > Like I said before, a hit is a hit and a miss is a miss, regardless it
> > is hitting the same data over and over again or hitting different data
> > every time. The usefulness of hit ratio depends on how it is being
> > used.
> >
>
> That last sentence is what I've been saying!
>

Then how could it be "largely" meaningless and ignored.

> > > And in particular, a low ratio does not mean 'start adding more memory',
> > > which is what you effectively said in the post that started this whole
> > > exchange: "If the cache hit is too low, even pure data warehouse can
> benefit
> > > from some extra memory".
> > >
> >
> > How this statement could be translated into "start adding more memory
> > when hit ratio is low" is beyond me. Even so it is not completely
> > false.
>
> To coin a phrase: either it is false or it is true. Being 'not completely
> false' is, I take it, some new state of quantum reality you've just
> invented?
>

I did not invent it. Hit ratio is "largely meaningless" yet not meaningless. It is not meaningless yet can be ignored. It is not quantum reality, rather quantum theory.

> >Besides hit ratio was not even the topic.
>
> So that makes your statement about low ratios being curable by adding memory
> a sensible one? Nope.
>

It is a least as sensible as low ratio meaning SQL tuning.

> >I was simply saying
> > the performance can benefit from extra memory, thus memory limitation
> > on 32-bit matters. Of course, every statement you make here is subject
> > to exceptions like what if the CPU is too slow or SQLs are not tuned.
> >
>
> This one is subject to its own internal exceptions: the hit ratio is a poor
> guide to whether more memory would be useful. You can throw in all sorts of
> extraneous red herrings if you wish, but it's that central point that is at
> issue.
>

Like I said depends on how you use it.

> > > Only when a whole lot of other indicators are taken into account might
> that
> > > statement have some grain of truth in it.
> >
> > That can be said about most of the indicators.
>
> Well, so long as you can say it about this one, we are in agreement.
>
> End of thread, I think, since you seem happy to do things your way, and I
> wouldn't want to further challenge the closed mindset you evince.

I think we only disagree on whether hit ratio should be ignored. So far you really haven't produced any convincing arguments to support your conclusion. Nevertheless, it has been an intriguing discussion. I strongly encourage visitors to read the entire thread. Received on Mon Oct 07 2002 - 12:01:04 CDT

Original text of this message

HOME | ASK QUESTION | ADD INFO | SEARCH | E-MAIL US