Re: Re: oracle can ignore hints
- From: <ryan.gaffuri@xxxxxxx>
- To: oracle-l@xxxxxxxxxxxxx
- Date: Fri, 5 Mar 2004 8:20:00 -0500
9204. I cant really explain the problem Im having with performance, its system
and data dependent. That comment was per Oracle support and spoken in general.
Most of the people here are on sites with oracle support.
maybe some others should open a TAR and ask? Given how much money my company
pays in supports costs I never feel bad about opening them.
>
> From: Kresimir Fabijanic <kfabijanic@xxxxxxxxxxxxxxx>
> Date: 2004/03/05 Fri AM 03:41:21 EST
> To: oracle-l@xxxxxxxxxxxxx
> Subject: Re: oracle can ignore hints
>
> 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."
> >
> >
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