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From: Daniel Morgan <damorgan@x.washington.edu>
Newsgroups: comp.databases.oracle.server
Subject: Re: system statistics
Date: Thu, 09 Oct 2003 22:26:34 -0700
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Jonathan Lewis wrote:

>I hadn't looked very closely at the dbms_xplan
>output since I still prefer my own format, but
>I did a quick check on 9.2.0.3 on W2000.
>In the absence of system stats, I got the
>'cpu costing not active' warning, and when
>I created some system stats, the warning
>disappeared.
>
>A couple of points:
>    do a query against sys.aux_stats$
>    to check the value of the stats, if
>    sreadtim or mreadtim is -1, then the
>    statistics will not be used.  You may
>    have collected over a period that did
>    no file system request for one or other
>    type of read.
>
>    remember that cursor are not invalidated
>    (at least, on some versions) when you
>    collect stats, so try doing a flush shared_pool
>    before running explain plan so that you get
>    new hard parse.
>
>
>--
>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
>____Iceland__November (tbc)
>____Belgium__November (EOUG event)
>____UK_______December (UKOUG conference)
>
>
>Three-day seminar:
>see http://www.jlcomp.demon.co.uk/seminar.html
>____USA__October
>____UK___November
>
>
>The Co-operative Oracle Users' FAQ
>http://www.jlcomp.demon.co.uk/faq/ind_faq.html
>
>  
>
Thanks. I'll beat it up some more and try again.

-- 
Daniel Morgan
http://www.outreach.washington.edu/ext/certificates/oad/oad_crs.asp
http://www.outreach.washington.edu/ext/certificates/aoa/aoa_crs.asp
damorgan@x.washington.edu
(replace 'x' with a 'u' to reply)