Ubuntu Manpage: pg_ctl - initialize, start, stop, or control a PostgreSQL server

Provided by: postgresql-15_15.7-0ubuntu0.23.10.1_amd64

NAME

       pg_ctl - initialize, start, stop, or control a PostgreSQL server

SYNOPSIS

       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 logrotate [-D datadir] [-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]

DESCRIPTION

pg_ctl is a utility for initializing a PostgreSQL database cluster, starting, stopping, or
restarting the PostgreSQL database 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.

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(1) 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 disallows new
connections, then waits for all existing clients to disconnect. 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. 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.

logrotate mode rotates the server log file. For details on how to use this mode with
external log rotation tools, see Section 25.3.

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.

OPTIONS

-c
--core-files
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.

-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 initdb-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
--silent
Print 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
--version
Print 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, pg_ctl 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 (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.

-?
--help
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.

Options for Windows
-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 password
Password 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.

ENVIRONMENT

       PGCTLTIMEOUT
           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.

       PGDATA
           Default 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 34.15).

       For additional variables that affect the server, see postgres(1).

FILES

       postmaster.pid
           pg_ctl examines this file in the data directory to determine whether the server is
           currently running.

       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.

EXAMPLES

   Starting the Server
       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

   Stopping the Server
       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
       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

   Showing the Server Status
       Here is sample status output from pg_ctl:

           $ pg_ctl status

           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.