RE: cursor_sharing - similar vs force
- From: "Taylor, Chris David" <ChrisDavid.Taylor@xxxxxxxxxxxxxxx>
- To: "'kylelf@xxxxxxxxx'" <kylelf@xxxxxxxxx>
- Date: Wed, 9 Jun 2010 07:03:43 -0500
Wouldn't FORCE include the SAME problems as SIMILAR?
I was always under the impression that the flow was EXACT->SIMILAR->FORCE, so
that SIMILAR behaves a "little" like FORCE but not quite as aggressive.
Chris Taylor
Sr. Oracle DBA
Ingram Barge Company
Nashville, TN 37205
Office: 615-517-3355
Cell: 615-354-4799
Email: chris.taylor@xxxxxxxxxxxxxxx<mailto:chris.taylor@xxxxxxxxxxxxxxx>
CONFIDENTIALITY NOTICE: This e-mail and any attachments are confidential and
may also be privileged. If you are not the named recipient, please notify the
sender immediately and delete the contents of this message without disclosing
the contents to anyone, using them for any purpose, or storing or copying the
information on any medium.
From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On
Behalf Of kyle Hailey
Sent: Tuesday, June 08, 2010 3:40 PM
To: ORACLE-L
Subject: cursor_sharing - similar vs force
I've seen good results with cursor_sharing=force and seen many issues of bugs
using cursor_sharing=similar.
I don't know of any bugs on cursor_sharing=force, but imagine there are. Any
people been bitten trying to use cursor_sharing=force?
And if there are bugs (which I'm sure there are) how likely the might show up.
Anything to watch out for in particular?
Of course "force" could cause users having different plans to end up with the
same plan - the bind variable peaking problem.
Similar on the other hand seems to be pretty risky.
I blogged on an example of how bad cursor_sharing=similar can be here:
http://db-optimizer.blogspot.com/2010/06/cursorsharing-picture-is-worth-1000.html
Best Wishes
Kyle Hailey
http://oraclemonitor.com
Other related posts:
