First question is whether you're in Cost Based or Rule Based optimization.
In RBO you are correct that it will read tables right to left unless
instructed otherwise by a hint.
In CBO, Oracle will choose what it thinks is 'best', which most of the time,
but not all of the time :), will be true.
Jay Miller
-----Original Message-----
Sent: Friday, April 06, 2001 6:45 AM
To: Multiple recipients of list ORACLE-L
Hi friends ,
I have got some query regarding , how the query is exactly executed ??
We always take joins and if we see the plan of the query , there is always
one
main driving table . Some times I get feeling that , in the join the right
most table is the driving table . But that is not always true , this is my
observation from several plans .
In Oracle documentation alos ita mentioned that ( Server Concepts, 815 or
816
: Optimisation of Joins ), "one driving table is selected" , but at least I
cannot makeout which of the several tables will be selected as driving table
.
What can be the potential criterions of selecting a driving table ?
Please , if you all can throw some light on the same or can redirect to some
document , that would be great .
Cheers ,
Anup Saxena
-------------------------------------------------------------------
The contents of this e-mail are confidential to the ordinary user
of the e-mail address to which it was addressed and may also be
privileged. If you are not the addressee of this e-mail you should
not copy, forward, disclose or otherwise use it or any part of it
in any form whatsoever. If you have received this e-mail in error
please notify us by telephone or e-mail the sender by replying to
this message, and then delete this e-mail and other copies of it
from your computer system. Thank you.
We reserve the right to monitor all e-mail communications through
our network.
--
Please see the official ORACLE-L FAQ: http://www.orafaq.com
--
Author:
INET: [EMAIL PROTECTED]
Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051
San Diego, California -- Public Internet access / Mailing Lists
--------------------------------------------------------------------
To REMOVE yourself from this mailing list, send an E-Mail message
to: [EMAIL PROTECTED] (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: Miller, Jay
INET: [EMAIL PROTECTED]
Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051
San Diego, California -- Public Internet access / Mailing Lists
--------------------------------------------------------------------
To REMOVE yourself from this mailing list, send an E-Mail message
to: [EMAIL PROTECTED] (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).
