Shutting Down the Server

PostgreSQL 7.3.4 Documentation
Prev | Chapter 3. Server Run-time Environment | Next

# 3.6. Shutting Down the Server

There are several ways to shut down the database server. You control the type of shutdown by sending different signals to the server process.

SIGTERM

  After receiving SIGTERM, the postmaster disallows new connections, but lets existing backends end their work normally. It shuts down only after all of the backends terminate normally. This is Smart Shutdown.

SIGINT

  The postmaster disallows new connections and sends all existing backends SIGTERM, which will cause them to abort their current transactions and exit promptly. It then waits for the backends to exit and finally shuts down. This is Fast Shutdown.

SIGQUIT

  This is Immediate Shutdown, which will cause the postmaster to send a SIGQUIT to all backends and exit immediately (without properly shutting itself down). The backends likewise exit immediately upon receiving SIGQUIT. This will lead to recovery (by replaying the WAL log) upon next start-up. This is recommended only in emergencies.

> Important: It is best not to use SIGKILL to shut down the postmaster. This will prevent the postmaster from releasing shared memory and semaphores, which may then have to be done by manually.

The PID of the postmaster process can be found using the ps program, or from the file `postmaster.pid` in the data directory. So for example, to do a fast shutdown:

    $ kill -INT `head -1 /usr/local/pgsql/data/postmaster.pid`

The program pg_ctl is a shell script that provides a more convenient interface for shutting down the postmaster.

Prev | Home | Next
Managing Kernel Resources | Up | Secure TCP/IP Connections with SSL