Re: long runtimes cured by cutting hash_area_size by 90% - ???

The general principle is that multiple
hash joins can be running concurrently
and Oracle 8 is not very sensible about
choosing how to exercise damage limitation when this occurs. (As it often does in
warehouse systems).

The side-effects, which are very much
query and data depended, are extreme
uses of memory, or extreme thrashing
of temporary space.

Regards

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

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  who can answer the questions, but the
  person who can question the answers -- T. Schick Jr

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The Co-operative Oracle Users' FAQ
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• Original Message ----- To: "Multiple recipients of list ORACLE-L" <ORACLE-L_at_fatcity.com> Sent: 14 April 2003 06:03 ???

> Just now catching up on email and though this question may be a bit
late,
> what are some of the nasties you refer to?
>
> Larry G. Elkins
> elkinsl_at_flash.net
>
> > Was this a parallel query ? Very nasty things
> > can happen with PQ and multiple concurrent
> > hashes. (And just plain nasty things can
> > happen with concurrent hashes and serial
> > queries).
> >

-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.net
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Author: Jonathan Lewis
  INET: jonathan_at_jlcomp.demon.co.uk

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