Gavin Flower <gavinflo...@archidevsys.co.nz> writes: >>> If we're going to extend pg_stat_statements, even more than min and max >>> I'd like to see the standard deviation in execution time.
> How about the 'median', often a lot more useful than the 'arithmetic > mean' (which most people call the 'average'). AFAIK, median is impossible to calculate cheaply (in particular, with a fixed amount of workspace). So this apparently innocent request is actually moving the goalposts a long way, because the space per query table entry is a big concern for pg_stat_statements. regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers