On Tue, Jul 10, 2018 at 01:54:12PM -0400, Patrick Hemmer wrote: > I'm looking for a way of gathering performance stats in a more usable > way than turning on `log_statement_stats` (or other related modules). > The problem I have with the log_*_stats family of modules is that they > log every single query, which makes them unusable in production. Aside > from consuming space, there's also the problem that the log system > wouldn't be able to keep up with the rate. > > There are a couple ideas that pop into mind that would make these stats > more usable: > 1. Only log when the statement would otherwise already be logged. Such > as due to the `log_statement` or `log_min_duration_statement` settings. Did you see: (Added Adrien to Cc); https://commitfest.postgresql.org/18/1691/ I don't think the existing patch does what you want, but perhaps all that's needed is this: if (save_log_statement_stats) + if (log_sample_rate==1 || was_logged) ShowUsage("EXECUTE MESSAGE STATISTICS"); In any case, I'm thinking that your request could/should be considered by whatever future patch implements sampling (if not implemented/included in the patch itself). If that doesn't do what's needed, that patch might still be a good crash course in how to start implementing what you need (perhaps on top of that patch). > 2. Make stats available in `pg_stat_statements` (or alternate view that > could be joined on). The block stats are already available here, but > others like CPU usage, page faults, and context switches are not. pg_stat_statements is ./contrib/pg_stat_statements/pg_stat_statements.c which is 3k LOC. getrusage stuff and log_*_stat stuff is in src/backend/tcop/postgres.c Justin
