On Sat, Nov 12, 2011 at 7:04 AM, Cody Caughlan <toolbag@xxxxxxxxx> wrote: > Postgres 9.1.1, master with 2 slaves via streaming replication. > > I've enabled slow query logging of 150ms and am seeing a large number > of slow COMMITs: > > 2011-11-12 06:55:02 UTC pid:30897 (28/0-0) LOG: duration: 232.398 ms > statement: COMMIT > 2011-11-12 06:55:08 UTC pid:30896 (27/0-0) LOG: duration: 1078.789 ms > statement: COMMIT Could well be related to checkpoints. Please try log_checkpoints = on and see if there is a correlation. > Recently we have bumped up wal_keep_segments and checkpoint_segments > because we wanted to run long running queries on the slaves and we're > receiving cancellation errors on the slaves. I think the master was > recycling WAL logs from underneath the slave and thus canceling the > queries. Hence, I believed I needed to crank up those values. It seems > to work, I can run long queries (for statistics / reports) on the > slaves just fine. That reasoning isn't sound because it doesn't work like that. Recycling WAL files has nothing to do with query cancelation on hot standby. -- Simon Riggs http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
