pg_ctl — initialize, start, stop, or control a PostgreSQL server
i[mmediate] ] [
i[mmediate] ] [
On Microsoft Windows, also:
d[emand] ] [
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.
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
command. See initdb for
start mode launches a new server.
The server is started in the background, and its standard input is
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
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
append the server's output to a log file. Use of either
-l or output redirection is
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
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,
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 (
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
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
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
Attempt 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.
Specifies the file system location of the database configuration
files. If this option is omitted, the environment variable
PGDATA is used.
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
Specifies the shutdown mode.
mode can be
immediate, or the first letter of one
of these three. If this option is omitted,
fast is the default.
Specifies options to be passed directly to the
can be specified multiple times, with all the given options being
usually be surrounded by single or double quotes to ensure that
they are passed through as a group.
Specifies options to be passed directly to the
be specified multiple times, with all the given options being
should usually be surrounded by single or double quotes to ensure
that they are passed through as a group.
Specifies the location of the
postgres executable. By default the
postgres executable is taken from the same
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
postgres executable was not
init mode, this option
analogously specifies the location of the
Print only errors, no informational messages.
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
Print the pg_ctl version and exit.
Wait for the operation to complete. This is supported for the
register, and is the default for those modes.
checks the server's PID file,
sleeping for a short amount of time between checks. Startup is
considered complete when the PID
file indicates that the server is ready to accept connections.
Shutdown is considered complete when the server removes the
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
pg_ctl exits with a nonzero exit status. But note
that the operation might continue in the background and eventually
Do not wait for the operation to complete. This is the opposite
of the option
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
Show 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.
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
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
Name of the system service to register. This name will be used
as both the service name and the display name. The default is
Password for the user to run the service as.
Start type of the system service.
start-type can be
the first letter of one of these two. If this option is omitted,
auto is the default.
User name for the user to run the service as. For domain users,
use the format
Default limit on the number of seconds to wait when waiting for startup or shutdown to complete. If not set, the default is 60 seconds.
Default data directory location.
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.
pg_ctl examines this file in the data directory to determine whether the server is currently running.
If this file exists in the data directory, pg_ctl (in
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
To start the server, waiting until the server is accepting connections:
To start the server using port 5433, and running without
pg_ctl -o "-F -p 5433" start
To stop the server, use:
-m option allows control over
how the server shuts
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:
-o is specified, that
replaces any previous options. To restart using port 5433,
fsync upon restart:
pg_ctl -o "-F -p 5433" restart
Here is sample status output from pg_ctl:
pg_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.
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