Yep.
Simple example: Even though it seems to be sometimes a
little on the 'random' side, the ELAPSED_TIME column
on V$SQL in v9 is an absolute god send...
Cheers
Connor
- Mogens_Nørgaard <mln_at_miracleas.dk> wrote: > And I
think it's important to realise that ratios
> are useless as a
> starting point in the tuning process on any system,
> not only Oracle.
> Most OS'es and databases use not instrumented
> correctly to deal with
> response time measurements (makes you wonder: If
> response TIME is what
> matters, how can you then not measure exactly that -
> time?) - so in the
> other worlds (Unix, VMS, Windows, SQL Server, MySQL,
> DB2....) people
> still beleive in the ratios because they have
> nothing better.
>
> Mogens
>
> Anjo Kolk wrote:
>
> >BCHR tuning is useless as a starting point in the
> tuning process.
> >
> >Anjo.
> >
> >-----Original Message-----
> >Yong Huang
> >Sent: Wednesday, December 24, 2003 6:09 PM
> >To: Multiple recipients of list ORACLE-L
> >
> >
> >[This message is not technical, but educational.
> Readers interested in
> >technical info only may want to skip]
> >
> >Hi, Cary and Gopal,
> >
> >My last message is misunderstood. Nowadays most
> DBAs that still use
> >buffer cache hit ratio as a primary performance
> tuning method are those
> >that rarely browse public forums. When we convince
> them that's a wrong
> >method, we should not say "Look. I can bump up BCHR
> to an arbitrary
> >value". If he doesn't think, he'll say "Indeed. If
> I can get any value,
> >it must be rubbish". But if he's a logical person
> and thinks for a few
> >minutes, he'll say "It's unfair to run that
> choose_a_hit_ratio program
> >to get an arbitrary hit ratio and say the method is
> wrong, because you
> >can use the same logic to write a program to get an
> arbitrary library
> >cache hit ratio, OS in-core inode cache hit ratio
> or directory name
> >cache hit..."
> >
> >My last message is not meant to revive the outdated
> and probably never
> >correct tuning method. Instead it's meant to let
> oracle-l members know
> >that when you need to convince those DBAs that
> still use that method,
> >you need to accuse the BCHR method for correct
> reason, namely, BCHR does
> >not contain sufficient information for tuning, not
> because you can raise
> >its value by constantly scanning a table in Oracle;
> you won't be able to
> >convince some stubbon DBAs who enjoy thinking in a
> quiet place.
> >
> >I agree that "It's not the ratio that needs
> condemning, it's the advice
> >about..." What I disagree is the wrong educational
> tool people on public
> >forums have recently used again and again to show
> the inadequacy of the
> >BCHR tuning method.
> >
> >Yong Huang
> >
> >__________________________________
> >Do you Yahoo!?
> >New Yahoo! Photos - easier uploading and sharing.
> >http://photos.yahoo.com/
> >
> >
>
> --
> Please see the official ORACLE-L FAQ:
> http://www.orafaq.net
> --
> Author: =?ISO-8859-1?Q?Mogens_N=F8rgaard?=
> INET: mln_at_miracleas.dk
>
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Received on Mon Dec 29 2003 - 08:14:24 CST
