RE: optimizer_max_permutations

From: John Kanagaraj <john.kanagaraj_at_hds.com>
Date: Tue, 26 Aug 2003 09:54:35 -0800
Message-ID: <F001.005CD4C4.20030826095435@fatcity.com>

Just fyi - it seems that Oracle had realized this in advance and has specifically instructed the Oracle Applications 11i installations to set this to 2000.

John Kanagaraj
DB Soft Inc
Phone: 408-970-7002 (W)

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• The opinions and facts contained in this message are entirely mine and do not reflect those of my employer or customers **

-----Original Message-----
Sent: Tuesday, August 26, 2003 8:55 AM
To: Multiple recipients of list ORACLE-L

One thing that the docs don't mention is that '80000' (the default in 8) is also a special boundary value. Anything less than 80,000 changes some of ways the optimizer does it work, ie, its not just a reduction in permutations.

Can't remember the specifics - join orders spring to mind but there is a metalink note about it.

Because of this, there's a school of thought that even on 8i, adopting the (9i default) value of 2000 will improve the "general" optimizer performance (ie the quality of the decisions it makes).

Cheers
Connor

• "Boivin, Patrice J" <BoivinP_at_mar.dfo-mpo.gc.ca> wrote: > Has anyone worked with this one?
  >
  >
  http://download-west.oracle.com/docs/cd/A87860_01/doc/server.817/a76961/ch11
  > 23.htm#81357
  >
  <http://download-west.oracle.com/docs/cd/A87860_01/doc/server.817/a76961/ch1
  > 123.htm#81357>
  >
  > Patrice.
  >
  

  ---

Connor McDonald
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Received on Tue Aug 26 2003 - 12:54:35 CDT