RE: ** optimizer_dynamic_sampling

Brandon,
   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 <Brandon.Allen@xxxxxxxxxxx> wrote:


From: Allen, Brandon <Brandon.Allen@xxxxxxxxxxx>
Subject: RE: ** optimizer_dynamic_sampling
To: "ajoshi977@xxxxxxxxx" <ajoshi977@xxxxxxxxx>, "oracle-l@xxxxxxxxxxxxx" 
<oracle-l@xxxxxxxxxxxxx>
Date: Friday, June 26, 2009, 5:28 PM








The sampling levels are described here:
 
http://download.oracle.com/docs/cd/B19306_01/server.102/b14211/stats.htm#sthref1118
 
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.
 
Regards,
Brandon


Privileged/Confidential Information may be contained in this message or 
attachments hereto. Please advise immediately if you or your employer do not 
consent to Internet email for messages of this kind. Opinions, conclusions and 
other information in this message that do not relate to the official business 
of this company shall be understood as neither given nor endorsed by it.



      

Other related posts: