Re: Cost vs Rule

Is your setting for db_file_multiblock_count too high? What's the optimizer mode? Have you set any of the optimizer_index_???? parameters in the initialization file? These parameters might be driving Oracle to prefer a full table scan over a index scan.

My 1.2 cents (after NY Taxes).

Raj

                                                                                                                    
                    Joe Raube                                                                                       
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                    Sent by:             Subject:     Re: Cost vs Rule                                              
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                    March 07,                                                                                       
                    2002 02:43 PM                                                                                   
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How much have you played with Oracle Hints???

-Joe

• "Magaliff, Bill" <Bill.Magaliff_at_lendware.com> wrote:
  > I work in a dev shop - most of the sql is canned and pretty basic.
  > We've
  > been running CBO in all of our dev environments, but we have a few
  > long txns
  > that just take forever. At the request of some savvy developers, I
  > turned
  > on RBO, and it brought down execution times dramatically.
  >
  > I've been analyzing affected tables often (we do a lot of bulk
  > load/unload
  > for testing), and have played with partitioning and clustering,
  > particularly
  > on one table that's just a dog. CBO will always do a FTS where RBO
  > uses the
  > PK to retrieve data.
  >
  > Where to go next? I've been unable to alter the costs dramatically
  > enough
  > to make any real difference in execution time.
  >
  > thx
  >
  > --
  

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