pg_ctl(1)
PG_CTL(1) PostgreSQL Server Applications PG_CTL(1)
NAME
pg_ctl - start, stop, or restart a PostgreSQL server
SYNOPSIS
pg_ctl start [ -w ] [ -s ] [ -D datadir ] [ -l filename ]
[ -o options ] [ -p path ]
pg_ctl stop [ -W ] [ -s ] [ -D datadir ] [ -m
[ s[mart] ] [ f[ast] ] [ i[mmediate] ]
]
pg_ctl restart [ -w ] [ -s ] [ -D datadir ] [ -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 ] [ -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 ter-
minal 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
redirected 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 all the clients to disconnect. This is the
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default. ``Fast'' mode does not wait for clients to discon-
nect. 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 sig-
nal, causing it to reread its configuration files
(postgresql.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 speci-
fied 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 pro-
cess. This is particularly valuable for Microsoft Windows
which does not have a kill command. Use --help to see a list
of supported signal names.
register mode allows you to register a system service on
Microsoft Windows.
unregister mode allows you to unregister a system service on
Microsoft Windows, previously registered with the register
command.
OPTIONS
-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 disal-
lowed by default.
-m mode
Specifies the shutdown mode. mode may 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.
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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.
-w Wait for the start or shutdown to complete. Times out
after 60 seconds. This is the default 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
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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 running or not.
postmaster.opts.default
If this file exists in the data directory, pg_ctl (in
start mode) will pass the contents of the file as
options to the postgres command, unless overridden by
the -o option.
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 may fail if access control is set up so that a local
client cannot connect without manual interaction (e.g.,
password authentication).
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
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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 pre-
viously 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 res-
tarting:
$ 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.
SEE ALSO
postgres(1)
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