On Fri, Apr 10, 2020 at 12:51:03AM +1000, Maxim Boguk wrote: > With database on dedicated server I encountered unusual load profile: > multi thread (200 connections static size pool via pgbouncer) insert only > into single table around 15.000 insert/s. > > Usually insert took 0.025ms and amount active backends (via > pg_stat_activity) usually stay in 1-5-10 range. > But every so while (few times per minute actually) number of active backend > go up to all 200 allowed connections. > Which lead to serious latency in latency sensitive load. > > No problem with IO latency or CPU usage found during performance analyze. > syncronous_commit = off Can you share other settings ? shared_buffers, checkpoint_*, bgwriter_* and max_wal_size ? And version() > And always one backend in SLRUSync. > > If anyone can have any good idea whats going on in that case and how I can > fix it - any ideas welcome. > So far I out of ideas. This might be useful: pg_stat_bgwriter view. I suggest to follow others advice and make a cronjob to do this every ~5 minutes: | INSERT INTO jrn_pg_stat_bgwriter SELECT now(), * FROM pg_stat_bgwriter; and write a window function to show values/time, or rrd graphs or whatever. -- Justin
