How to stop/start a postgres db

Lab: How to stop/start a postgres db

As postgres user (recommendation is never allow direct connection to postgres, allow other users with su to switch to postgres user).

Start:

[postgres@localhost ~]$ pg_ctl -D /pgData/data -l logfile start
waiting for server to start.... done
server started

[postgres@localhost ~]$
Where /pgData/data is the datafile directory where the postgres database is stored
Examine the postgres db status:

[postgres@localhost ~]$ ps -ef|grep -i postgres
root      9284  9269  0 02:40 pts/0    00:00:00 su - postgres
postgres  9285  9284  0 02:40 pts/0    00:00:00 -bash
postgres  9319     1  0 02:42 ?        00:00:00 /pgBin/12.5/bin/postgres -D /pgData/data
postgres  9321  9319  0 02:42 ?        00:00:00 postgres: checkpointer
postgres  9322  9319  0 02:42 ?        00:00:00 postgres: background writer
postgres  9323  9319  0 02:42 ?        00:00:00 postgres: walwriter
postgres  9324  9319  0 02:42 ?        00:00:00 postgres: autovacuum launcher
postgres  9325  9319  0 02:42 ?        00:00:00 postgres: stats collector
postgres  9326  9319  0 02:42 ?        00:00:00 postgres: logical replication launcher
postgres  9327  9285  0 02:42 pts/0    00:00:00 ps -ef
postgres  9328  9285  0 02:42 pts/0    00:00:00 grep --color=auto -i postgres
[postgres@localhost ~]$

9319 is the parent process for the postgres process tree

[postgres@localhost ~]$ pg_ctl status -D /pgData/data
pg_ctl: server is running (PID: 9319)
/pgBin/12.5/bin/postgres "-D" "/pgData/data"
[postgres@localhost ~]$

Stop:

[postgres@localhost ~]$ pg_ctl -D /pgData/data stop
waiting for server to shut down.... done
server stopped
[postgres@localhost ~]$

Status:

[postgres@localhost ~]$ pg_ctl status -D /pgData/data
pg_ctl: no server running
[postgres@localhost ~]$