All other things being equal (and there
are a couple of pages in the performance
tuning guide outlining some things that
are not equal - like joins conditions, indexed
columns, subqueries, user-defined functions
etc.) the 'final' predicates against a single table
are evaluated from the bottom up under RBO and
from the top down under CBO.
Everything is subject to change, of course -
so if you are using cpu_costing in version 9
you may already have discovered that Oracle
will ignore the above and re-arrange the order
of the 'final' predicates against a single table
to minimise the CPU cost of evaluating them.
In your case it appears that the RBO eliminates
the problem rows because none of them get
through the last two predicates:
PROJECT_ORDER = 'Y'
and ORDER_STATUS ='O'
Regards
Jonathan Lewis
http://www.jlcomp.demon.co.uk
Coming soon one-day tutorials:
Cost Based Optimisation
Trouble-shooting and Tuning
Indexing Strategies
(see http://www.jlcomp.demon.co.uk/tutorial.html )
____UK_______March 19th
____USA_(FL)_May 2nd
Next Seminar dates:
(see http://www.jlcomp.demon.co.uk/seminar.html )
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The Co-operative Oracle Users' FAQ
http://www.jlcomp.demon.co.uk/faq/ind_faq.html
----- Original Message -----
To: "Multiple recipients of list ORACLE-L" <[EMAIL PROTECTED]>
Sent: 26 February 2003 05:18
> I have an application query that runs fine in RBO mode but failing
in CBO with ORA-01722: invalid number -
>
> select /*+ rule */ ORDER_NO,ITEM_NO
> from [EMAIL PROTECTED]
> where ORDER_NO = 4432089
> and PROJECT_ORDER = 'Y' and ORDER_STATUS ='O'
>
> ORDER_NO ITEM_NO
> ---------- --------------------
> 4432089 TOOLING COSTS
>
> 1 row selected.
>
> select /*+ choose */ ORDER_NO,ITEM_NO
> from [EMAIL PROTECTED]
> where ORDER_NO = 4432089
> and PROJECT_ORDER = 'Y' and ORDER_STATUS ='O'
>
> ERROR:
> ORA-01722: invalid number
> ORA-02063: preceding line from DB01.WORLD
>
> no rows selected
>
> ORDER_NO column is varchar2 field and it may be containing some
non-numeric data, so I understand that Oracle may be doing implicit
conversion on order_no. But, then why it is working fine in RULE
based. The explain plan is same in both cases and is using FULL Table
access. The table has unique index on ORDER no.
>
--
Please see the official ORACLE-L FAQ: http://www.orafaq.net
--
Author: Jonathan Lewis
INET: [EMAIL PROTECTED]
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