Oracle FAQ | Your Portal to the Oracle Knowledge Grid |
![]() |
![]() |
Home -> Community -> Mailing Lists -> Oracle-L -> RE: Join cardinality and query tuning.
That is the problem - I don't have enough permissions to take 10053 trace. Getting any such trace is a headache. If there is absolutely no other way, then I will try replicating this on some other environment.
Thanks & regards,
Charu.
-----Original Message-----
From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org]On Behalf Of Wolfgang Breitling
Sent: Wednesday, November 03, 2004 2:49 PM
To: joshic_at_mahindrabt.com; oracle-l_at_freelists.org
Subject: RE: Join cardinality and query tuning.
Can you run a 10053 event trace and post the trace? It will show all the
statistics and values the optimizer uses to calculate the join cardinality.
Maybe that will shed some light on the "mystery". I have seen many cases
where
the CBO's join selectivity calculation is different from the formula you
use,
which you got from my paper and which I got from a metalink note.
Quoting Charu Joshi <joshic_at_mahindrabt.com>:
>
> Thanks Lex,
>
> Then why is the row-source cardinality shown in the Explain Plan radically
> different from the one calculated using this formula (Please refer to my
> original post.)? Is there any silly mistake in my calculations (I quite am
> prone to that.)?
>
-- regards Wolfgang Breitling Oracle 7,8,8i,9i OCP DBA Centrex Consulting Corporation www.centrexcc.com -- http://www.freelists.org/webpage/oracle-l ********************************************************* Disclaimer: This message (including any attachments) contains confidential information intended for a specific individual and purpose, and is protected by law. If you are not the intended recipient, you should delete this message and are hereby notified that any disclosure, copying, or distribution of this message, or the taking of any action based on it, is strictly prohibited. ********************************************************* Visit us at http://www.mahindrabt.com -- http://www.freelists.org/webpage/oracle-lReceived on Wed Nov 03 2004 - 03:22:49 CST
![]() |
![]() |