Oracle-L: RE: RE: RE: CONSISTANT GETS

From: <Jared.Still_at_radisys.com>
Date: Fri, 15 Nov 2002 15:04:53 -0800
Message-ID: <F001.00504D41.20021115150453@fatcity.com>

Ethan,

A NOT EXISTS can be very expensive if returning large numbers of rows from the driving table. It's a correlated subquery as Stephane F. pointed out in another post.

Jared

"Post, Ethan" <Ethan.Post_at_ps.net>
Sent by: root_at_fatcity.com
11/15/2002 10:32 AM
Please respond to ORACLE-L

        To:     Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>
        cc: 
        Subject:        RE: RE: RE: CONSISTANT GETS

Hold the press. NOT IN better than NOT EXISTS? Is this theory or fact? If
so is there any supporting evidence out there? This is the first I have heard of this.

Thanks!

-----Original Message-----
Sent: Friday, November 15, 2002 11:35 AM To: Multiple recipients of list ORACLE-L

Jerry,

I suspect that the improvments are more likely due to your rewriting the WHERE clause rather than the use of NOT EXISTS.

Especially if the database were 9i, where NOT IN actually seems get a better execution path than NOT EXISTS.

That original WHERE clause is really a piece of work.

Jared

--

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

Author: Post, Ethan
INET: Ethan.Post_at_ps.net

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).

--

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

Author:
INET: Jared.Still_at_radisys.com

Fat City Network Services    -- 858-538-5051 http://www.fatcity.com
San Diego, California        -- Mailing list and web hosting services
---------------------------------------------------------------------