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Re: 8i to 9i migration, performance issues

From: Jonathan Lewis <jonathan_at_jlcomp.demon.co.uk>
Date: Thu, 1 Apr 2004 08:06:37 +0000 (UTC)
Message-ID: <c4giic$o0q$1@sparta.btinternet.com>

Final comment (probably) 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

April 2004 Iceland  http://www.index.is/oracleday.php
June  2004      UK - Optimising Oracle Seminar


"Jonathan Lewis" <jonathan_at_jlcomp.demon.co.uk> wrote in message
news:c4dtmt$ij6$1_at_titan.btinternet.com...

> The 9.2 manual does not have the words "or costs" at the end. This tends
> to suggest that 10g (unhinted) does take costs into account when
considering
> unnesting. However, until I can find an example where 9i and 10g produce
> different 10053 traces, I'm not going to commit myself on that just yet.
>
I've just upgraded from 10.1.0.1 to 10.1.0.2, and my first test on a non-correlated subquery showed 10r2 going through five times as many options as 10r1 and 9r2 before closing on a plan. There were a couple of interesting variations in options that suggested that some of the problems that people see at present in the 8i -> 9i upgrade will disappear in 10g.
Received on Thu Apr 01 2004 - 02:06:37 CST

Original text of this message

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