Re: What is null event ? (CPU Hungry vs. Tom)

pagesflames_at_usa.net said...
> Karsten Farrell <kfarrell_at_belgariad.com> wrote in message news:<MPG.1947f03bf801d9ca9897a4_at_news.la.sbcglobal.net>...
> > You might want to head over to the AskTom site. He doesn't have much,
> > but you can search for "null event" (include the quotes) and get a
> > couple of hits, including this document (url will wrap):
> >
> > http://asktom.oracle.com/pls/ask/f?p=4950:8:1090762::NO::F4950_P8
> > _DISPLAYID,F4950_P8_CRITERIA:6108562636780,
> >
> > Basically, unless you compare diffs between two snapshots, the "null
> > event" is meaningless.
> >
> > BTW, be sure to read Tom's "other common sense things I hear all the
> > time". It's his followup to the 5 Feb 2003 question from CPU Hungry (Tom
> > does have a sense of humor).
>
> However, I think that "CPU hungry didn't talk a bulls**t and was right
> from his point of view. Tom's 99.99999999999% of peak CPU usage is
> great from technical point of view, but from productional, processing
> or financial point of view is better to stick on 60 - 90% depending on
> application, organization and other factors.
>
>
> --
> Dusan Bolek
>

Yes, I mostly agree with you. High cpu utilization is not a bad thing if you seldom have other processes waiting on that resource. However, in the real database world you seldom find this pure state, which is what I think you're saying. A cpu that consistently runs at near 100% will find many processes waiting many times.

My comment wasn't meant to validate (or invalidate) what Tom said about cpu utilization. It was meant to call attention to the common sense things he hears all the time, which I'll paraphrase here (hope Tom doesn't mind) so people don't think I'm referring to something else:

o everyone knows indexes need to be rebuilt periodically o you must separate tables from indexes by tablespace o segments should have as few extents as possible; one extent being best o a cold backup is better than a hot one o you should shutdown your database frequently o if your query doesn't use indexes, CBO did the wrong thing o adding more CPU will make your system faster

-- 
/Karsten
DBA > retired > DBA