Hi all. I have a task to create HA PostgreSQL cross datacenter cluster. I created a test bed on VirtualBox and I simulate different failures and disastrous in loops. And got one of funny bug of the Postgresql (11.4). One of the clusters has two instances of PostgreSQL on port 5433 and 5434. After simulating unexpected power off of the node the lock files of PostgreSQL still exist in /tmp directory. And on recovery the first instance on port 5433 starts without problem, but the second instance sometimes not. The reason is that the PID in /tmp/.s.PGSQL.5434.lock sometimes point to the one of process of PostgereSQL on port 5433, for instance the logger.
1408 ? S 0:00 /usr/pgsql-11/bin/postgres -D /var/lib/pgsql/krogan0a 1415 ? Ss 0:00 \_ postgres: logger 1416 ? Ss 0:02 \_ postgres: startup recovering 000000030000000000000007 1417 ? Ss 0:00 \_ postgres: checkpointer 1418 ? Ss 0:00 \_ postgres: background writer 1419 ? Ss 0:00 \_ postgres: stats collector 1420 ? Ss 0:10 \_ postgres: walreceiver streaming 0/7269290 # cat /tmp/.s.PGSQL.5434.lock 1415 /var/lib/pgsql/krogan0b 1565355860 5434 /tmp # sudo -u postgres /usr/pgsql-11/bin/pg_ctl -D /var/lib/pgsql/krogan0b start waiting for server to start....2019-08-09 16:52:25.685 MSK [6673] LOG: listening on IPv4 address "0.0.0.0", port 5434 2019-08-09 16:52:25.685 MSK [6673] LOG: listening on IPv6 address "::", port 5434 2019-08-09 16:52:25.686 MSK [6673] LOG: listening on Unix socket "/var/run/postgresql/.s.PGSQL.5434" 2019-08-09 16:52:25.686 MSK [6673] FATAL: lock file "/tmp/.s.PGSQL.5434.lock" already exists 2019-08-09 16:52:25.686 MSK [6673] HINT: Is another postmaster (PID 1415) using socket file "/tmp/.s.PGSQL.5434"? 2019-08-09 16:52:25.686 MSK [6673] LOG: database system is shut down stopped waiting pg_ctl: could not start server Examine the log output. So it will be good if postgres will check not only PID, but also that the different postgres is running on different or same port. And is there some workaround?
