RE: CBO not using the index even though it is faster when hinted

Yes ... I can force the hint, but why wont it take the RBO path ? Its a difference of 7 seconds versus a split second. So why would the CBO take that path ?

-----Original Message-----
Sent: Friday, January 24, 2003 1:14 PM
To: Multiple recipients of list ORACLE-L hinted

Well, if it can do it under rule-based, then it shouldn't be able to ignore the hint
under CBO - I don't suppose there's
any chance that you have a typo in
the hint ?

Regards

Jonathan Lewis
http://www.jlcomp.demon.co.uk

Coming soon a new one-day tutorial:
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-----Original Message-----
To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com> Date: 24 January 2003 21:06
hinted

>All the columns in the table are not null ...
>
>here is an interesting test I ran ...
>
>several Direct_Path_Write and Read waits with large elasped times
>are showing up in the 10046 trace data on this query due to the
>full table scan.
>
>Just deleted statistics on this and fwiw ...
>
>With Statistics ....
>=====================
>
>SELECT Statement Optimizer=Choose (Cost=225 ...)
> SORT (Order By) (Cost=225 ...)
> Table Access (Full) of 'table1'
>
>Physical Reads = 433
>
>Without Statistics ..
>======================
>
>SELECT Statement Optimizer=Choose
> Table Access (By Index Row) of 'table1
> Index ( Full Scan ) of 'concatenated index' (Non-Unique)
>
>Physical Reads = 0
>
>Mike

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