"Merlin Moncure" <merlin.moncure@xxxxxxxxxxxxx> writes: >> The cost depends on your usage patterns. I did tests with one of >> my applications and saw no significant performance difference for >> simple selects, but a series of insert/update/delete operations ran >> about 30% slower when block- and row-level statistics were enabled >> versus when the statistics collector was disabled. > That approximately confirms my results, except that the penalty may even > be a little bit higher in the worst-case scenario. Row level stats hit > the hardest if you are doing 1 row at a time operations over a > persistent connection. IIRC, the only significant cost from enabling stats is the cost of transmitting the counts to the stats collector, which is a cost basically paid once at each transaction commit. So short transactions will definitely have more overhead than longer ones. Even for a really simple transaction, though, 30% seems high --- the stats code is designed deliberately to minimize the penalty. regards, tom lane
