Re: Oracle Database Resource Manager

From: Jonathan Lewis <jonathan_at_jlcomp.demon.co.uk>
Date: Mon, 3 May 2004 21:49:26 +0100
Message-ID: <009101c43150$1fb1d7b0$7102a8c0@Primary>

Notes in-line.

Regards

Jonathan Lewis
http://www.jlcomp.demon.co.uk

The Co-operative Oracle Users' FAQ
http://www.jlcomp.demon.co.uk/faq/ind_faq.html

Optimising Oracle Seminar
http://www.jlcomp.demon.co.uk/seminar.html

June 2004 UK Manchester
July 2004 Iceland
July 2004 USA California
Aug 2004 USA North Carolina
Sept 2004 UK Manchester
Sept 2004 USA NYC
Oct 2004 USA Boston

Original Message ----- From: "Pete Sharman" <peter.sharman_at_oracle.com> To: <oracle-l_at_freelists.org> Cc: "Peter Ross Sharman" <PETER.SHARMAN_at_oracle.com> Sent: Monday, May 03, 2004 8:27 PM Subject: RE: Oracle Database Resource Manager

I don't know who the instructor was, but he or she is talking crap (pardon = my French). Really, what would be the point of implementing a resource man= ager that itself takes too many resources?

[jl] Good question - I asked myself the same thing when
[jl] I first ran the 9.0.1 resource manager on my HP-UX
[jl] box. Under some conditions the overhead was about
[jl] 100%. Things improved when the sampling rate was
[jl] dropped somewhat.

One thing that people get confused about with the Resource Manager, BTW, is=
 when it actually takes effect.  It's when the resource being managed is ex=
hausted i.e. if you're allocating different amounts of the CPU utilization =
to different groups, you WON'T see Resource Manager kick in until CPU utili=

zation hits 100%. After all, it's not a problem till then, right?

[jl] I've found that it tends to kick in only after the demand
[jl] exceeds about 200% of available resources; and then
[jl] the allocation fractions aren't obeyed particularly well.
[jl] One of the positive things about it though is that you
[jl] can set it up to error out any SQL whose calculated
[jl] cost exceeds a given limit - which means less of the
[jl] 'query from hell' stuff wrecking performance for
[jl] everyone else on the system.

Please see the official ORACLE-L FAQ: http://www.orafaq.com

To unsubscribe send email to: oracle-l-request_at_freelists.org put 'unsubscribe' in the subject line.

--
Archives are at http://www.freelists.org/archives/oracle-l/
FAQ is at http://www.freelists.org/help/fom-serve/cache/1.html
-----------------------------------------------------------------

Received on Mon May 03 2004 - 15:46:34 CDT