Re: Deadly OPTIMIZER_SECURE_VIEW_MERGING=TRUE

On Dec 3, 12:01 am, "shortcut..._at_googlemail.com" <shortcut..._at_googlemail.com> wrote:
> On 2 Dez., 20:24, Rick Denoire <educacion.super..._at_online.de> wrote:
>
> > Hello Robert
>
> > I spent two weeks (!) investigating the question.
> > I required support from the vendor, sent them detailed informations.
> > I let users do different tests.
> > I collected and printed performance numbers, execution plans, looked
> > into waits, used AWR, ADDM, SQL Tuning Advisors, statistics
> > with/without histograms. I was playing with different init parameters
> > (mostly making things even worse). I set up a clone database, did more
> > tests... hey! Let's stop.
>
> > As you can see from other replies, you are guessing wrong. (Typical
> > case when people try to complicate obvious things).
>
> What exactly did I guess? While you mention "obvious": all the items
> you list above were not obvious from your first posting. All that you
> mentioned was that "after some investigation" you found an
> undocumented parameter that seemingly fixed the issue. While you are
> obviously aware of all this, others are not.

You might check, that happens to be documented. The documentation has words that you can search on for more information, like "view merging" and "query rewrite."

>
> > If the software is just misbehaving, all this knowledge is for
> > nothing. Almost every query was doing FTS of huge tables, main
> > activity was direct path read. Same application was still installed in
> > the old server running 9i: Execution plans were completely different.
> > So what? It could have been something different than direct path
> > reads, it does not bear any direct logical relationship to the
> > solution. Based on this "knowledge", you would probably... buy more
> > disks?? Wrong!
>
> No need to get agitated.

I think problems that lead to the incorrect database data should lead to agitation, such as the bug Noons was referring to. Simply spending money on disk unnecessarily might reasonably lead to a lesser amount of agitation, though personally I'll use up as much as I can take, since proper capacity planning seems useless.

jg

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