Re: Periodic Stats Collection -- CBO Stats Myth?

Hi Wolfgang,

Thans for your valuable inputs.

if the min and max are out of the sample data then they are not real end point values. Going back to original quetsion, does this mean that we do not need to recollect/ re adjust ( using PREPARE_COLUMN_VALUES)?. I agree that May be we cannot completely get away with outdated end point values but the periodicity of collection/adjustment can be quite less ( say once in a month).

Best Regards

Sriram Kumar

On Fri, Oct 3, 2008 at 4:00 PM, Wolfgang Breitling <breitliw_at_centrexcc.com>wrote:

> 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
>

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