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Home -> Community -> Mailing Lists -> Oracle-L -> 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_at_cox.net 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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