|The PostgreSQL 9.0 Reference Manual - Volume 3 - Server Administration Guide
by The PostgreSQL Global Development Group
Paperback (6"x9"), 274 pages
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3.5 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 master
This is the Smart Shutdown mode.
SIGTERM, the server disallows new connections, but lets existing sessions end their work normally. It shuts down only after all of the sessions terminate. If the server is in online backup mode, it additionally waits until online backup mode is no longer active. While backup mode is active, new connections will still be allowed, but only to superusers (this exception allows a superuser to connect to terminate online backup mode). If the server is in recovery when a smart shutdown is requested, recovery and streaming replication will be stopped only after all regular sessions have terminated.
This is the Fast Shutdown mode.
The server disallows new connections and sends all existing
SIGTERM, which will cause them to abort their current transactions and exit promptly. It then waits for all server processes to exit and finally shuts down. If the server is in online backup mode, backup mode will be terminated, rendering the backup useless.
This is the Immediate Shutdown mode.
postgresprocess will send a
SIGQUITto all child processes and exit immediately, without properly shutting itself down. The child processes 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.
pg_ctl program provides a convenient
interface for sending these signals to shut down the server.
Alternatively, you can send the signal directly using
on non-Windows systems.
The PID of the
postgres process can be
found using the
ps program, or from the file
‘postmaster.pid’ in the data directory. For
example, to do a fast shutdown:
$ kill -INT `head -1 /usr/local/pgsql/data/postmaster.pid`
Important: It is best not to use
SIGKILLto shut down the server. Doing so will prevent the server from releasing shared memory and semaphores, which might then have to be done manually before a new server can be started. Furthermore,
postgresprocess without letting it relay the signal to its subprocesses, so it will be necessary to kill the individual subprocesses by hand as well.
To terminate an individual session while allowing other sessions to
pg_terminate_backend() (see Volume 1A: Table 7-55) or send a
SIGTERM signal to the child process associated with
|ISBN 9781906966072||The PostgreSQL 9.0 Reference Manual - Volume 3 - Server Administration Guide||See the print edition|