RE: ** optimizer_dynamic_sampling

From: A Joshi <>
Date: Fri, 26 Jun 2009 17:34:05 -0700 (PDT)
Message-ID: <>

   Thanks. I mean if there are statistics already on the table : then : what is the need to do more sampling : is it to take care of changes to the table since the statistics were gathered. And is it not a overhead. So would this benefit only cases where the table data changes a lot?  
Another question is does this affect in any way  the automatic gather of statistics done by job GATHER_STATS_JOB in dba_scheduler_jobs. IS there a way to disable it using dba account or can it be disabled as SYS only.    
Apart from setting optimizer_dynamic_sampling=1 and disabling GATHER_STATS_JOB  : do I need to do any disable to have control over statistics. Thanks
  • On Fri, 6/26/09, Allen, Brandon <> wrote:

From: Allen, Brandon <> Subject: RE: ** optimizer_dynamic_sampling To: "" <>, "" <> Date: Friday, June 26, 2009, 5:28 PM

The sampling levels are described here:  
I haven’t had any problems with auto_sample_size in 10g, but I’ve heard rumors that it’s much better/faster in 11g.  Another big change to keep in mind is that in 10g histograms will be gathered by default.  

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-- Received on Fri Jun 26 2009 - 19:34:05 CDT

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