On Wed, Jan 29, 2014 at 6:06 AM, Andrew Dunstan <and...@dunslane.net> wrote: > mportance is in the eye of the beholder. As far as I'm concerned, min and > max are of FAR less value than stddev. If stddev gets left out I'm going to > be pretty darned annoyed, especially since the benchmarks seem to show the > marginal cost as being virtually unmeasurable. If those aren't enough for > you, perhaps you'd like to state what sort of tests would satisfy you.
I certainly agree that stddev is far more valuable than min and max. I'd be inclined to not accept the latter on the grounds that they aren't that useful. So, am I correct in my understanding: The benchmark performed here [1] was of a standard pgbench SELECT workload, with no other factor influencing the general overhead (unlike the later test that queried pg_stat_statements as well)? I'd prefer to have seen the impact on a 32 core system, where spinlock contention would naturally be more likely to appear, but even still I'm duly satisfied. There was no testing of the performance impact prior to 6 days ago, and I'm surprised it took Mitsumasa that long to come up with something like this, since I raised this concern about 3 months ago. [1] http://www.postgresql.org/message-id/52e10e6a.5060...@lab.ntt.co.jp -- Peter Geoghegan -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers