Re: Periodic Stats Collection -- CBO Stats Myth?
From: Wolfgang Breitling <breitliw_at_centrexcc.com>
Date: Fri, 03 Oct 2008 14:00:31 -0600
Message-Id: <200810032000.m93K0aCK012329@mail90c0.megamailservers.com>
Date: Fri, 03 Oct 2008 14:00:31 -0600
Message-Id: <200810032000.m93K0aCK012329@mail90c0.megamailservers.com>
gather_table_stats with an estimate_percent of less than 100 uses the
sample option of the from clause, e.g. select ... from tbl sample(10)
and determine the min and max values for columns based on the values
in the rows returned by the sample.
At 12:50 PM 10/3/2008, Sriram Kumar wrote:
>Hi Tim,
>
>Thanks for your inputs. Appriciate your inputs.
>
>I had one more question. If we are performing sampling ( lets say 10
>percent), how does the stats gatherer estimate the high value
>especially for date columns?.
>
>Best Regards
>
>Sriram Kumar
>
Regards
Wolfgang Breitling
Centrex Consulting Corporation
www.centrexcc.com
-- http://www.freelists.org/webpage/oracle-lReceived on Fri Oct 03 2008 - 15:00:31 CDT