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
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
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
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 (
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
register mode registers the
PostgreSQL server as a system
service on Microsoft Windows.
-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
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.
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
-o can be specified multiple
times, with all the given options being passed
should 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
-o can be specified multiple times, with
all the given options being passed through.
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 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
executable was not found.
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
variable or, if not set, to 60 seconds.
Print the pg_ctl version and exit.
Wait for the operation to complete. This is supported
for the modes
register, and is the default for those
repeatedly 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 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
pg_ctl exits with a nonzero
exit status. But note that the operation might continue
in the background and eventually succeed.
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 the
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
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
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
demand, or 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 34.14).
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,
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
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
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,
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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