Re: Auto stats gathering is not sufficient - what now?

  • From: Greg Rahn <greg@xxxxxxxxxxxxxxxxxx>
  • To: david@xxxxxxxxxxxxxxxxxx
  • Date: Thu, 10 Feb 2011 09:31:48 -0800

I would advise against that.  Dynamic Sampling (DS) does not have the
same information that you get from dbms_stats.

"The most common misconception is that DS can be used as a substitute
for optimizer statistics." 2nd sentence from
http://blogs.oracle.com/optimizer/2010/08/dynamic_sampling_and_its_impact_on_the_optimizer.html


On Thu, Feb 10, 2011 at 12:16 AM, David Aldridge
<david@xxxxxxxxxxxxxxxxxx> wrote:
> You could consider not gathering statistics at all -- delete current
> statistics and lock the table statistics -- and rely on dynamic sampling.
> The usual duration of reporting queries against large tables, particularly
> the consequences for the duration if the execution plan is incorrect,
> generally make the dynamic sampling overhead acceptable.
-- 
Regards,
Greg Rahn
http://structureddata.org
--
//www.freelists.org/webpage/oracle-l


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