Re: Oracle, Siebel and rule-based optimization

From: Connor McDonald <hamcdc_at_yahoo.co.uk>
Date: Sat, 01 Feb 2003 18:48:43 -0800
Message-ID: <F001.00541746.20030201184843@fatcity.com>

A similar approach is to set optimizer_mode to rule but analyze everything and then use the
FIRST_ROWS/ALL_ROWS/CHOOSE hint on custom queries...

Still, RBO is a step back into the dark ages...No hash join, no cpu costing, no function based indexes, no etc etc etc etc

Cheers
Connor

• Jared Still <jkstill_at_cybcon.com> wrote: > On Friday 31 January 2003 07:09, Michael Fontana
  > wrote:
  > >
  > > Still, some of the queries in Siebel SEEM to run
  > better using CBO. Is
  > > there any way to mix and match approaches? To use
  > RBO by default, but
  > > perhaps CBO might make sense for certain queries,
  > and perhaps some
  > > AD-HOC?
  >
  > The problem with using CBO for 'some' queries is
  > that analyzing a table
  > turns on CBO for every query the table is used in,
  > not just the ones
  > you wish.
  >
  > Tony's approach sounds interesting enough to make me
  > start playing
  > with plan stabilility. Like I don't have enough to
  > do. :)
  >
  > Jared
  > --
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  > Author: Jared Still
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Connor McDonald
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Received on Sat Feb 01 2003 - 20:48:43 CST