Oracle-L: RE: Oracle's use of Indexes

From: Jamadagni, Rajendra <Rajendra.Jamadagni_at_espn.com>
Date: Tue, 03 Jun 2003 13:34:59 -0800
Message-ID: <F001.005A9479.20030603133459@fatcity.com>

Wolfgang,

I have a similar problem that I am still trying to work on.

Except for
* nls_sort ('binary' => performance is better,

null it is bad)
and

sort_area_size (8388608 => bad performance, 8688000 => good performance)

all other parameter are same (from 10053 trace). With good performance, query returns in 3-4 seconds, for bad performance it is more than 1 minute. We must have the output in less than 5 seconds (worst case).

I am still playing with it though ... this is all 9202 ... one thing i have noticed is that explain plan is different.

Let's see if I find anything ...
Raj

Rajendra dot Jamadagni at nospamespn dot com All Views expressed in this email are strictly personal. QOTD: Any clod can have facts, having an opinion is an art !

-----Original Message-----
Sent: Tuesday, June 03, 2003 4:55 PM
To: Multiple recipients of list ORACLE-L

The cardinalities are the same, but the costs are different. It looks as if production has somehow optimizer_index_cost_adj set to 50 or lower or has db_file_multiblock_read_count set to 8. It's the same instance so that is not possible unless they are changed at a session level. To check that, or any other init.ora differences that may be of importance select the name-value pairs from v$parameter in both schemas and do a diff. Of course the easiest is to diff 10053 event traces and see where they deviate, which will hopefully provide a clue as to why.

-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.net
-- 
Author: Jamadagni, Rajendra
  INET: Rajendra.Jamadagni_at_espn.com

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_at_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).



text/plain attachment: ESPN_Disclaimer.txt

Received on Tue Jun 03 2003 - 16:34:59 CDT