Stopping the server in an emergency

In this recipe, we will show you the command that can be used to stop the server in an emergency situation.

How to do it...

We can use the following command to stop the PostgreSQL server in an emergency:

pg_ctl -D /var/lib/pgsql/9.6/data stop -m immediate

Here, the data directory location is defined at /var/lib/pgsql/9.6/data.

How it works...

The moment the immediate stop mode is used with the pg_ctl command, all the users have their transactions aborted and the existing connections are terminated. There is no system checkpoint either and the database basically requires crash recovery at the time of database restart.

In this shutdown mode, the PostgresSQL process will issue a direct SIGQUIT signal to each of the child processes, by including the backend processes such as bgwriter, autovacuum, and recovery processes. However, in smart shutdown mode, the PostgreSQL process will wait until these processes are terminated and then shut down the postmaster process.