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Re: Any thoughts?

From: Jim Kennedy <>
Date: Fri, 30 Apr 2004 06:04:19 GMT
Message-ID: <D%lkc.1558$AV4.60358@attbi_s04>

"Howard J. Rogers" <> wrote in message news:4091e982$0$14771$
> Sybrand Bakker wrote:
> > On Fri, 30 Apr 2004 12:49:04 +1000, "Howard J. Rogers"
> > <> wrote:
> >
> >
> >>Just for the record, Google reports me as being the only person who
> >>responded to you last time, and that response was a question as to what
> >>your colleagues at TUSC made of it.
> >>
> >>That was hardly a flame.
> >>
> >>I agree it was nothing.
> >>
> >>But a flame it wasn't.
> >
> >
> >
> > Which does confirm his TUSC relationships ;-)
> Oh, the TUSC relationship is irrelevant really, except that I would have
> thought they would have been the first people to turn to, and their
> ideas might have been of interest in their own right (which is why I
> asked the question). It shouldn't stop someone being able to ask a
> question here, just because they happen to be associated with TUSC, just
> as it shouldn't if someone works for Oracle (!). On the other hand, he
> (presumably) has access to some of the more publicised experts in the
> Oracle publishing world, so one wonders whether they are stumped on the
> matter, or have even ever been asked about it.
> What really makes it difficult to provide any answer here is the lack of
> any substance to the question. I mean, is session logical reads always
> bigger than consistent gets+db block gets, or always smaller, or does it
> vary, and if it's one way or the other, what is he doing on the database
> at the time, and what's the version he's using in the first place, and
> on what O/S, and so on?
> And also, why is it important to know anyway? I mean, what's the problem
> being solved here? What piece of DBA work is stymied because of the
> inconsistency?
> I've studied a number of V$ statistics that "sound" like their supposed
> to add up to some other statistic, but never do. I tend not to lose much
> sleep over it, unless it poses a quantifiable (and practical) problem,
> because Oracle internals are, well, Oracle internals.
> Regards

My understanding (which may be incorrect) is that the V$ stats are not beholden to any "database consistency" and are just structures to track statistics. In fact, I have run across times when they are very inconsistent. (eg wait time writing to a file exceeding any reasonable number, due to async IO and the tracking got confused on when the write occured.) I am sure there are some subtle things that we may really never know about. I agree with your assesment. Jim Received on Fri Apr 30 2004 - 01:04:19 CDT

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