On Thu, Jan 14, 2010 at 1:11 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: > Greg Smith <g...@2ndquadrant.com> writes: >> Tom Lane wrote: >>> Actually, that brings up a more general question: what's with the >>> enthusiasm for clearing statistics *at all*? > >> ... Right now, you're still carrying around >> the history of the bad period forever though, and every check of the >> pg_stat_bgwriter requires manually subtracting the earlier values out. > > Seems like a more appropriate solution would be to make it easier to do > that subtraction, ie, make it easier to capture the values at a given > time point and then get deltas from there. It's more general (you could > have multiple saved sets of values), and doesn't require superuser > permissions to do, and doesn't have the same potential for > damn-I-wish-I-hadn't-done-that moments.
True, but it's also more complicated to use. Most systems I'm familiar with[1] that have performance counters just provide an option to clear them. Despite the disadvantages you cite, it seems to be fairly useful in practice; anyway, I have found it so. ...Robert [1] The other design I've seen is a system that automatically resets, say, once a day. It retains the statistics for the 24-hour period between the most recent two resets, and the statistics for the partial period following the last reset. But that doesn't seem appropriate for PostgreSQL.... -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
