Re: Add min and max execute statement time in pg_stat_statement

On 10/21/2013 04:43 PM, Peter Geoghegan wrote:
> On Mon, Oct 21, 2013 at 1:36 PM, Robert Haas <robertmhaas@gmail.com> wrote:
>> Yeah, and I worry about min and max not being very usable - once they
>> get pushed out to extreme values, there's nothing to drag them back
>> toward normality except resetting the stats, and that's not something
>> we want to encourage people to do frequently.
> My thoughts exactly. Perhaps it'd be useful to separately invalidate
> min/max times, without a full reset. But then you've introduced the
> possibility of the average time (total_time/calls) exceeding the max
> or being less than the min.
>
>


This is why I suggested the standard deviation, and why I find it would 
be more useful than just min and max. A couple of outliers will set the 
min and max to
possibly extreme values but hardly perturb the standard deviation over a 
large number of observations.

cheers

andrew