Return-Path: Received: from ensim.rackshack.net (root@localhost) by orafaq.net (8.11.6/8.11.6) with ESMTP id h45Kt1n28062 for ; Mon, 5 May 2003 15:55:01 -0500 X-ClientAddr: 209.68.248.164 Received: from newsfeed.cts.com (newsfeed.cts.com [209.68.248.164]) by ensim.rackshack.net (8.11.6/8.11.6) with ESMTP id h45Kt0A28054 for ; Mon, 5 May 2003 15:55:00 -0500 Received: from fatcity.com (uucp@localhost) by newsfeed.cts.com (8.9.3/8.9.3) with UUCP id LAA82676; Mon, 5 May 2003 11:30:03 -0700 (PDT) Received: by fatcity.com (26-Feb-2001/v1.0g-b72/bab) via UUCP id 0058FF3E; Mon, 05 May 2003 11:08:21 -0800 Message-ID: Date: Mon, 05 May 2003 11:08:21 -0800 To: Multiple recipients of list ORACLE-L X-Comment: Oracle RDBMS Community Forum X-Sender: Paula_Stankus@doh.state.fl.us Sender: root@fatcity.com Reply-To: ORACLE-L@fatcity.com Errors-To: ML-ERRORS@fatcity.com From: Paula_Stankus@doh.state.fl.us Subject: RE: Re: which should be faster Organization: Fat City Network Services, San Diego, California X-ListServer: v1.0g, build 72; ListGuru (c) 1996-2001 Bruce A. Bergman Precedence: bulk Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="----_=_NextPart_001_01C31331.B7601B00" ------_=_NextPart_001_01C31331.B7601B00 Content-Type: text/plain; charset="iso-8859-1" If the CBO now considers CPU costing couldn't it change the execution plan of tuned 8i queries to decrease throughput and possibly also degrade response time for a particular query? For example, I have a batch program I am running in parallel and since I know I will run it without other concurrent sessions (in a purely batch window) I am happy to use 80% of my CPU. Now in 9i CPU cost is taken into account, the CBO uses a different execution plan and the batch process is taking slower although throughput is increased? Oracle OCP DBA -----Original Message----- Sent: Monday, May 05, 2003 2:50 PM To: Multiple recipients of list ORACLE-L What I tried to say over the weekend was: Predicate order should not matter in 9i because you should be using CPU costing, and Oracle 9i will re-arrange predicate ordering to minimise CPU load, and report this fact in the explain plan. Predicate order CAN have an impact on 8.1.7 because Oracle 8i (and earlier) does not consider CPU cost when working out an execution plan. Regards Jonathan Lewis http://www.jlcomp.demon.co.uk The educated person is not the person who can answer the questions, but the person who can question the answers -- T. Schick Jr One-day tutorials: http://www.jlcomp.demon.co.uk/tutorial.html ____Denmark__May 21-23rd ____Sweden___June ____Finland__September ____Norway___September Three-day seminar: see http://www.jlcomp.demon.co.uk/seminar.html ____UK_(Manchester)_May x 2 ____Estonia___June (provisional) ____Australia_June (provisional) ____USA_(CA, TX)_August The Co-operative Oracle Users' FAQ http://www.jlcomp.demon.co.uk/faq/ind_faq.html ----- Original Message ----- To: "Multiple recipients of list ORACLE-L" Sent: 05 May 2003 18:01 > jonathan lewis posted over the weekend that it does. He said it does in 9i unless you have a certain parameter set. Cant remember what that was off-hand. > > > > > From: "AK" > > Date: 2003/05/05 Mon AM 11:46:41 EDT > > To: Multiple recipients of list ORACLE-L > > Subject: Re: which should be faster > > > > does predicate order makes diff in cob also ? > > oracle 8.1.7 > > -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Jonathan Lewis INET: jonathan@jlcomp.demon.co.uk Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru@fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). ------_=_NextPart_001_01C31331.B7601B00 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable RE: Re: which should be faster

If the CBO now considers CPU costing couldn't it = change the execution plan of tuned 8i queries to decrease throughput = and possibly also degrade response time for a particular query?  = For example, I have a batch program I am running in parallel and since = I know I will run it without other concurrent sessions (in a purely = batch window) I am happy to use 80% of my CPU.  Now in 9i CPU cost = is taken into account, the CBO uses a different execution plan and the = batch process is taking slower although throughput is = increased?



Oracle OCP DBA


-----Original Message-----
From: Jonathan Lewis [mailto:jonathan@jlcomp.demon= .co.uk]
Sent: Monday, May 05, 2003 2:50 PM
To: Multiple recipients of list ORACLE-L
Subject: Re: Re: which should be faster



What I tried to say over the weekend was:

Predicate order should not matter in 9i
because you should be using CPU costing,
and Oracle 9i will re-arrange predicate = ordering
to minimise CPU load, and report this fact
in the explain plan.

Predicate order CAN have an impact on
8.1.7 because Oracle 8i (and earlier) does
not consider CPU cost when working out
an execution plan.



Regards

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

  The educated person is not the person
  who can answer the questions, but the
  person who can question the answers -- T. = Schick Jr


One-day tutorials:
http://www.jlcomp.demon.co.uk/tutorial.html=

____Denmark__May 21-23rd
____Sweden___June
____Finland__September
____Norway___September

Three-day seminar:
see http://www.jlcomp.demon.co.uk/seminar.html
____UK_(Manchester)_May x 2
____Estonia___June (provisional)
____Australia_June (provisional)
____USA_(CA, TX)_August

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


----- Original Message -----
To: "Multiple recipients of list ORACLE-L" = <ORACLE-L@fatcity.com>
Sent: 05 May 2003 18:01


> jonathan lewis posted over the weekend that it = does. He said it does
in 9i unless you have a certain parameter set. Cant = remember what that
was off-hand.
>
> >
> > From: "AK" = <oramagic@hotmail.com>
> > Date: 2003/05/05 Mon AM 11:46:41 = EDT
> > To: Multiple recipients of list ORACLE-L = <ORACLE-L@fatcity.com>
> > Subject: Re: which should be faster
> >
> > does predicate order makes diff in cob = also ?
> > oracle 8.1.7
> >



--
Please see the official ORACLE-L FAQ: http://www.orafaq.net
--
Author: Jonathan Lewis
  INET: jonathan@jlcomp.demon.co.uk

Fat City Network Services    -- = 858-538-5051 http://www.fatcity.com
San Diego, = California        -- Mailing list = and web hosting services
---------------------------------------------------------------= ------
To REMOVE yourself from this mailing list, send an = E-Mail message
to: ListGuru@fatcity.com (note EXACT spelling of = 'ListGuru') and in
the message BODY, include a line containing: UNSUB = ORACLE-L
(or the name of mailing list you want to be removed = from).  You may
also send the HELP command for other information = (like subscribing).

------_=_NextPart_001_01C31331.B7601B00-- -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: INET: Paula_Stankus@doh.state.fl.us Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru@fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).