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PG_CTL(1) PostgreSQL Server Applications PG_CTL(1)

NAME
pg_ctl - start, stop, or restart a PostgreSQL server

SYNOPSIS
pg_ctl start [ -w ] [ -t seconds ] [ -s ] [ -D datadir ] [ -l filename ] [ -o options ] [ -p path ] [ -c ]

pg_ctl stop [ -W ] [ -t seconds ] [ -s ] [ -D datadir ] [ -m
s[mart] | f[ast] | i[mmediate]
]

pg_ctl restart [ -w ] [ -t seconds ] [ -s ] [ -D datadir ] [ -c ] [ -m
s[mart] | f[ast] | i[mmediate]
] [ -o options ]

pg_ctl reload [ -s ] [ -D datadir ]

pg_ctl status [ -D datadir ]

pg_ctl kill signal_name process_id

pg_ctl register [ -N servicename ] [ -U username ] [ -P password ] [ -D datadir ] [ -w ] [ -t seconds ] [ -s ] [
-o options ]

pg_ctl unregister [ -N servicename ]

DESCRIPTION
pg_ctl is a utility for starting, stopping, or restarting the PostgreSQL backend server (postgres(1)), or displaying the
status of a running server. Although the server can be started manually, pg_ctl encapsulates tasks such as redirecting
log output and properly detaching from the terminal and process group. It also provides convenient options for controlled
shutdown.

In start mode, a new server is launched. The server is started in the background, and standard input is attached to
/dev/null. The standard output and standard error are either appended to a log file (if the -l option is used), or redi-
rected to pg_ctl's standard output (not standard error). If no log file is chosen, the standard output of pg_ctl should
be redirected to a file or piped to another process such as a log rotating program like rotatelogs; otherwise postgres
will write its output to the controlling terminal (from the background) and will not leave the shell's process group.

In stop mode, the server that is running in the specified data directory is shut down. Three different shutdown methods
can be selected with the -m option: ``Smart'' mode waits for online backup mode to finish and all the clients to discon-
nect. This is the default. ``Fast'' mode does not wait for clients to disconnect and will terminate an online backup in
progress. All active transactions are rolled back and clients are forcibly disconnected, then the server is shut down.
``Immediate'' mode will abort all server processes without a clean shutdown. This will lead to a recovery run on restart.

restart mode effectively executes a stop followed by a start. This allows changing the postgres command-line options.

reload mode simply sends the postgres process a SIGHUP signal, causing it to reread its configuration files (post-
gresql.conf, pg_hba.conf, etc.). This allows changing of configuration-file options that do not require a complete
restart to take effect.

status mode checks whether a server is running in the specified data directory. If it is, the PID and the command line
options that were used to invoke it are displayed.

kill mode allows you to send a signal to a specified process. This is particularly valuable for Microsoft Windows which
does not have a kill command. Use --help to see a list of supported signal names.

unregister mode allows you to unregister a system service on Microsoft Windows, previously registered with the register
command.

OPTIONS
-c Attempt to allow server crashes to produce core files, on platforms where this available, by lifting any soft
resource limit placed on them. This is useful in debugging or diagnosing problems by allowing a stack trace to be
obtained from a failed server process.

-D datadir
Specifies the file system location of the database files. If this is omitted, the environment variable PGDATA is
used.

-l filename
Append the server log output to filename. If the file does not exist, it is created. The umask is set to 077, so
access to the log file from other users is disallowed by default.

-m mode
Specifies the shutdown mode. mode can be smart, fast, or immediate, or the first letter of one of these three.

-o options
Specifies options to be passed directly to the postgres command.

The options are usually surrounded by single or double quotes to ensure that they are passed through as a group.

-p path
Specifies the location of the postgres executable. By default the postgres executable is taken from the same
directory as pg_ctl, or failing that, the hard-wired installation directory. It is not necessary to use this
option unless you are doing something unusual and get errors that the postgres executable was not found.

-s Only print errors, no informational messages.

-t The number of seconds to wait when waiting for start or shutdown to complete.

-w Wait for the start or shutdown to complete. The default wait time is 60 seconds. This is the default option for
shutdowns. A successful shutdown is indicated by removal of the PID file. For starting up, a successful psql -l
indicates success. pg_ctl will attempt to use the proper port for psql. If the environment variable PGPORT exists,
that is used. Otherwise, it will see if a port has been set in the postgresql.conf file. If neither of those is
used, it will use the default port that PostgreSQL was compiled with (5432 by default). When waiting, pg_ctl will
return an accurate exit code based on the success of the startup or shutdown.

-W Do not wait for start or shutdown to complete. This is the default for starts and restarts.

OPTIONS FOR WINDOWS
-N servicename
Name of the system service to register. The name will be used as both the service name and the display name.

-P password
Password for the user to start the service.

-U username
User name for the user to start the service. For domain users, use the format DOMAIN\username.

ENVIRONMENT
PGDATA Default data directory location.

PGPORT Default port for psql(1) (used by the -w option).

For additional server variables, see postgres(1). This utility, like most other PostgreSQL utilities, also uses the
environment variables supported by libpq (see in the documentation).

FILES
postmaster.pid
The existence of this file in the data directory is used to help pg_ctl determine if the server is currently run-
ning or not.

postmaster.opts
If this file exists in the data directory, pg_ctl (in restart mode) will pass the contents of the file as options
to postgres, unless overridden by the -o option. The contents of this file are also displayed in status mode.

postgresql.conf
This file, located in the data directory, is parsed to find the proper port to use with psql when the -w is given
in start mode.

NOTES
Waiting for complete start is not a well-defined operation and might fail if access control is set up so that a local
client cannot connect without manual interaction (e.g., password authentication). For additional connection variables,
see in the documentation, and for passwords, also see in the documentation.

EXAMPLES
STARTING THE SERVER
To start up a server:

$ pg_ctl start

An example of starting the server, blocking until the server has come up is:

$ pg_ctl -w start

For a server using port 5433, and running without fsync, use:

$ pg_ctl -o "-F -p 5433" start

STOPPING THE SERVER
$ pg_ctl stop

stops the server. Using the -m switch allows one to control how the backend shuts down.

RESTARTING THE SERVER
Restarting the server is almost equivalent to stopping the server and starting it again except that pg_ctl saves and
reuses the command line options that were passed to the previously running instance. To restart the server in the sim-
plest form, use:

$ pg_ctl restart

To restart server, waiting for it to shut down and to come up:

$ pg_ctl -w restart

To restart using port 5433 and disabling fsync after restarting:

$ pg_ctl -o "-F -p 5433" restart

SHOWING THE SERVER STATUS
Here is a sample status output from pg_ctl:

$ pg_ctl status
pg_ctl: server is running (pid: 13718)
Command line was:
/usr/local/pgsql/bin/postgres '-D' '/usr/local/pgsql/data' '-p' '5433' '-B' '128'

This is the command line that would be invoked in restart mode.