Re: Better cardinality estimate when dialing optimizer_features_enable back

  • From: Greg Rahn <greg@xxxxxxxxxxxxxxxxxx>
  • To: Neil Kodner <nkodner@xxxxxxxxx>
  • Date: Tue, 24 Nov 2009 14:02:12 -0800

I (like Randolf) am a bit suspect that this is entirely just an
execution plan problem.  There seems to be some relationship to the IO
profile.  I think you need to get both a fast and slow execution
profile for the version and try and drill down on the
difference in the execution stats.  It may be useful to get a cold
cache, cold filesystem profile for each and an warm version also.

If it were truly just an execution plan problem then it should be
consistently reproducible for each and every execution.

On Tue, Nov 24, 2009 at 1:54 PM, Neil Kodner <nkodner@xxxxxxxxx> wrote:
>> What is the difference in execution time of the two queries in
>> allstats_both_queries.txt ?
>  Anywhere from a 30 seconds to none at all.  That's the puzzling thing.

Greg Rahn

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