2010/1/14 Tom Lane <t...@sss.pgh.pa.us>: > Rafael Martinez <r.m.guerr...@usit.uio.no> writes: >> Is there any chance of implementing a way of knowing when was the last >> time statistics delivered via pg_stat_* were reset? > > Actually, that brings up a more general question: what's with the > enthusiasm for clearing statistics *at all*? ISTM that's something > you should do only in dire emergencies, like the collector went > haywire and has now got a bunch of garbage numbers. The notion of > resetting subsets of the stats seems even more dubious, because now > you have numbers that aren't mutually comparable. So I fail to > understand why the desire to expend valuable development time on > any of this.
s/collector/application/ and you've got one reason. Example, that I hit the other day. Examining pg_stat_user_functions shows one function taking much longer than you'd expect. Called about 6 million times, total time about 7 days spent. Reason turned out to be a missing index. Without clearing the stats, it'll take a *long* time before the average goes down enough to make it possible to use the simple SELECT self_time/calls FROM pg_stat_user_functions WHERE... to monitor. Sure, if you have a system that graphs it, it'll update properly, but for the quick manual checks, that view suddenly becomes a lot less ueful. -- Magnus Hagander Me: http://www.hagander.net/ Work: http://www.redpill-linpro.com/ -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
