Re: But I *want* to use RBO!

From: Connor McDonald <hamcdc_at_yahoo.co.uk>
Date: Tue, 08 Oct 2002 13:58:37 -0800
Message-ID: <F001.004E3C02.20021008135837@fatcity.com>

Certainly a lot of the recursive SQL I've seen in traces is riddled with ORDERED, FIRST_ROWS or a long explicit list (ala outline style) hints

You get the feeling it was:

- explain SQL under RBO
- not down plan
- craft hints to make sure it does it under CBO

Cheers
Connor

• Tim Gorman <Tim_at_SageLogix.com> wrote: > RE: But I *want* to use RBO!The well-known problems
  > with using CBO to query the statistics-less data
  > dictionary had been resolved in Oracle9i, as
  > discussed in an earlier thread on this list. Not
  > sure how they fixed it, but I suspect that Oracle is
  > not throwing away the RBO code-base, but rather
  > absorbing the more useful parts of it into the CBO
  > for uses like querying the data dictionary. Either
  > that, or they have improved the constants applied in
  > the absence of statistics. Or both...?
  > ----- Original Message -----
  > From: Jacques Kilchoer
  > To: Multiple recipients of list ORACLE-L
  > Sent: Tuesday, October 08, 2002 1:54 PM
  > Subject: RE: But I *want* to use RBO!
  >
  >
  > > -----Original Message-----
  > > From: Jesse, Rich
  > [mailto:Rich.Jesse_at_qtiworld.com]
  > >
  > > No more RBO as of 10i...
  > >
  > >
  > http://metalink.oracle.com/metalink/plsql/ml2_documents.showDocument?p_database_id=NOT&p_id=189702.1
  >
  >
  > Does this mean Oracle is getting rid of their data
  > dictionary too? :)
  >
  >
  

  ---

Connor McDonald
http://www.oracledba.co.uk
http://www.oaktable.net

"Remember amateurs built the ark - Professionals built the Titanic"

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Received on Tue Oct 08 2002 - 16:58:37 CDT