Re: oracle can ignore hints

I have had that exact same experience.

Two Sun servers, different number of CPU's and RAM,
same versions of Oracle 7 down to the patch level,
data exported from one database into the other.

Strictly RBO, two very different execution paths.

Very frustrating, wish I could recall the solution we used.

Jared




On Fri, 2004-03-05 at 00:41, Kresimir Fabijanic wrote:
> Hi Ryan
> 
> What version of Oracle and OS are you running?  What hint did you try to 
> use?  How complex was query?
> 
> I have seen a case (OK it was 7.3.4.0 in 1999 on Sun's OS) where two 
> databases - same version, same OS same Oracle and OS patches on both - 
> hardware configuration was slightly different (not 100% sure but there 
> were differences in RAM (1G vs 2G or 4G) and number of CPUs - (2 vs 4) 
> and some disk layout differences) both databases running RULE (software 
> vendor requested [Keystone - if you have ever heard of it]) - identical 
> statement (cut and paste between two terminal sessions (and back)) 
> generating very different execution plans.
> 
> I tried to verify few times and results were consistently different.  
> Nothing would surprise me any more.
> 
> Kind regards
> 
> Kresimir Fabijanic
> 
> ryan.gaffuri@xxxxxxx wrote:
> 
> >We had a discussion on here regarding hints. some of you stated that Oracle 
> >cannot ignore a proper hint. I have a TAR open and asked about this. Here is 
> >the response.
> >
> >
> >
> >"A hint simply adds weight to a cost estimation, it can still be overridden 
> >by the CBO if the values aren't seen as useful."
> >
> >
> >----------------------------------------------------------------
> >Please see the official ORACLE-L FAQ: http://www.orafaq.com
> >----------------------------------------------------------------
> >To unsubscribe send email to:  oracle-l-request@xxxxxxxxxxxxx
> >put 'unsubscribe' in the subject line.
> >--
> >Archives are at http://www.freelists.org/archives/oracle-l/
> >FAQ is at http://www.freelists.org/help/fom-serve/cache/1.html
> >-----------------------------------------------------------------
> >
> >  
> >
> 
> ----------------------------------------------------------------
> Please see the official ORACLE-L FAQ: http://www.orafaq.com
> ----------------------------------------------------------------
> To unsubscribe send email to:  oracle-l-request@xxxxxxxxxxxxx
> put 'unsubscribe' in the subject line.
> --
> Archives are at http://www.freelists.org/archives/oracle-l/
> FAQ is at http://www.freelists.org/help/fom-serve/cache/1.html
> -----------------------------------------------------------------

----------------------------------------------------------------
Please see the official ORACLE-L FAQ: http://www.orafaq.com
----------------------------------------------------------------
To unsubscribe send email to:  oracle-l-request@xxxxxxxxxxxxx
put 'unsubscribe' in the subject line.
--
Archives are at http://www.freelists.org/archives/oracle-l/
FAQ is at http://www.freelists.org/help/fom-serve/cache/1.html
-----------------------------------------------------------------

Other related posts: