pg_ctl — initialize, start, stop, or control a PostgreSQL server
pg_ctl init[db] [-D datadir] [-s] [-o initdb-options]
pg_ctl start [-D datadir] [-l filename] [-W] [-t seconds] [-s] [-o options] [-p path] [-c]
pg_ctl stop [-D datadir] [-m
s[mart] | f[ast] | i[mmediate]
] [-W] [-t seconds] [-s]
pg_ctl restart [-D datadir] [-m
s[mart] | f[ast] | i[mmediate]
] [-W] [-t seconds] [-s] [-o options] [-c]
pg_ctl reload [-D datadir] [-s]
pg_ctl status [-D datadir]
pg_ctl promote [-D datadir] [-W] [-t seconds] [-s]
pg_ctl kill signal_name process_id
On Microsoft Windows, also:
pg_ctl register [-D datadir] [-N servicename] [-U username] [-P password] [-S
a[uto] | d[emand]
] [-e source] [-W] [-t seconds] [-s] [-o options]
pg_ctl unregister [-N servicename]
pg_ctl is a utility for initializing a PostgreSQL database cluster, starting, stopping, or restarting the PostgreSQL database server (postgres), 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.
The init or initdb mode creates a new
PostgreSQL database cluster, that is,
a collection of databases that will be managed by a single
server instance. This mode invokes the initdb
command. See initdb for details.
start mode launches a new server. The
server is started in the background, and its standard input is attached
to /dev/null (or nul on Windows).
On Unix-like systems, by default, the server's standard output and
standard error are sent to pg_ctl's
standard output (not standard error). The standard output of
pg_ctl should then 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. On
Windows, by default the server's standard output and standard error
are sent to the terminal. These default behaviors can be changed
by using -l to append the server's output to a log file.
Use of either -l or output redirection is recommended.
stop mode shuts down the server that is running in
the specified data directory. Three different
shutdown methods can be selected with the -m
option. “Smart” mode waits for all active
clients to disconnect and any online backup to finish.
If the server is in hot standby, recovery and streaming replication
will be terminated once all clients have disconnected.
“Fast” mode (the default) 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 immediately, without a clean shutdown. This choice
will lead to a crash-recovery cycle during the next server start.
restart mode effectively executes a stop followed
by a start. This allows changing the postgres
command-line options, or changing configuration-file options that
cannot be changed without restarting the server.
If relative paths were used on the command line during server
start, restart might fail unless
pg_ctl is executed in the same current
directory as it was during server start.
reload mode simply sends the
postgres server process a SIGHUP
signal, causing it to reread its configuration files
(postgresql.conf,
pg_hba.conf, etc.). This allows changing
configuration-file options that do not require a full server restart
to take effect.
status mode checks whether a server is running in
the specified data directory. If it is, the server's PID
and the command line options that were used to invoke it are displayed.
If the server is not running, pg_ctl returns
an exit status of 3. If an accessible data directory is not
specified, pg_ctl returns an exit status of 4.
promote mode commands the standby server that is
running in the specified data directory to end standby mode
and begin read-write operations.
kill mode sends a signal to a specified process.
This is primarily valuable on Microsoft Windows
which does not have a built-in kill command. Use
--help to see a list of supported signal names.
register mode registers the PostgreSQL
server as a system service on Microsoft Windows.
The -S option allows selection of service start type,
either “auto” (start service automatically on system startup)
or “demand” (start service on demand).
unregister mode unregisters a system service
on Microsoft Windows. This undoes the effects of the
register command.
-c--core-filesAttempt to allow server crashes to produce core files, on platforms where this is possible, by lifting any soft resource limit placed on core files. This is useful in debugging or diagnosing problems by allowing a stack trace to be obtained from a failed server process.
-D datadir--pgdata=datadir Specifies the file system location of the database configuration files. If
this option is omitted, the environment variable
PGDATA is used.
-l filename--log=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 is disallowed to other users by default.
-m mode--mode=mode Specifies the shutdown mode. mode
can be smart, fast, or
immediate, or the first letter of one of
these three. If this option is omitted, fast is
the default.
-o options--options=options Specifies options to be passed directly to the
postgres command.
-o can be specified multiple times, with all the given
options being passed through.
The options should usually be surrounded by single or
double quotes to ensure that they are passed through as a group.
-o initdb-options--options=initdb-options Specifies options to be passed directly to the
initdb command.
-o can be specified multiple times, with all the given
options being passed through.
The options should usually be 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.
In init mode, this option analogously
specifies the location of the initdb
executable.
-s--silentPrint only errors, no informational messages.
-t seconds--timeout=seconds Specifies the maximum number of seconds to wait when waiting for an
operation to complete (see option -w). Defaults to
the value of the PGCTLTIMEOUT environment variable or, if
not set, to 60 seconds.
-V--versionPrint the pg_ctl version and exit.
-w--wait Wait for the operation to complete. This is supported for the
modes start, stop,
restart, promote,
and register, and is the default for those modes.
When waiting for startup, pg_ctl repeatedly
attempts to connect to the server.
When waiting for shutdown, pg_ctl waits for
the server to remove its PID file.
pg_ctl returns an exit code based on the
success of the startup or shutdown.
If the operation does not complete within the timeout (see
option -t), then pg_ctl exits with
a nonzero exit status. But note that the operation might continue in
the background and eventually succeed.
-W--no-wait Do not wait for the operation to complete. This is the opposite of
the option -w.
If waiting is disabled, the requested action is triggered, but there is no feedback about its success. In that case, the server log file or an external monitoring system would have to be used to check the progress and success of the operation.
In prior releases of PostgreSQL, this was the default except for
the stop mode.
-?--helpShow help about pg_ctl command line arguments, and exit.
If an option is specified that is valid, but not relevant to the selected operating mode, pg_ctl ignores it.
-e source Name of the event source for pg_ctl to use
for logging to the event log when running as a Windows service. The
default is PostgreSQL. Note that this only controls
messages sent from pg_ctl itself; once
started, the server will use the event source specified
by its event_source parameter. Should the server
fail very early in startup, before that parameter has been set,
it might also log using the default event
source name PostgreSQL.
-N servicename Name of the system service to register. This name will be used
as both the service name and the display name.
The default is PostgreSQL.
-P passwordPassword for the user to run the service as.
-S start-type Start type of the system service. start-type can
be auto, or demand, or
the first letter of one of these two. If this option is omitted,
auto is the default.
-U username User name for the user to run the service as. For domain users, use the
format DOMAIN\username.
PGCTLTIMEOUTDefault limit on the number of seconds to wait when waiting for startup or shutdown to complete. If not set, the default is 60 seconds.
PGDATADefault data directory location.
Most pg_ctl modes require knowing the data directory
location; therefore, the -D option is required
unless PGDATA is set.
pg_ctl, like most other PostgreSQL
utilities,
also uses the environment variables supported by libpq
(see Section 33.14).
For additional variables that affect the server, see postgres.
postmaster.pidpg_ctl examines this file in the data directory to determine whether the server is currently running.
postmaster.optsIf 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.
To start the server, waiting until the server is accepting connections:
$pg_ctl start
To start the server using port 5433, and
running without fsync, use:
$pg_ctl -o "-F -p 5433" start
To stop the server, use:
$pg_ctl stop
The -m option allows control over
how the server shuts down:
$pg_ctl stop -m smart
Restarting the server is almost equivalent to stopping the
server and starting it again, except that by default,
pg_ctl saves and reuses the command line options that
were passed to the previously-running instance. To restart
the server using the same options as before, use:
$pg_ctl restart
But if -o is specified, that replaces any previous options.
To restart using port 5433, disabling fsync upon restart:
$pg_ctl -o "-F -p 5433" restart
Here is sample status output from pg_ctl:
$pg_ctl statuspg_ctl: server is running (PID: 13718) /usr/local/pgsql/bin/postgres "-D" "/usr/local/pgsql/data" "-p" "5433" "-B" "128"
The second line is the command that would be invoked in restart mode.