pg\_ctl

pg\_ctl

1

Application

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

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 {#app-pg-ctl-description}
===========

pg\_ctl is a utility for initializing a PostgreSQL database cluster,
starting, stopping, or restarting the PostgreSQL database server
([???](#app-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
[???](#app-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 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
[???](#logfile-maintenance).

`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 {#app-pg-ctl-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 {#app-pg-ctl-windows-options}
-------------------

`-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
    [???](#guc-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 [???](#libpq-envars)).

For additional variables that affect the server, see
[???](#app-postgres).

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 {#r1-app-pgctl-2}
========

Starting the Server {#r2-app-pgctl-3}
-------------------

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 {#r2-app-pgctl-4}
-------------------

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 {#r2-app-pgctl-5}
---------------------

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 {#r2-app-pgctl-6}
-------------------------

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.

See Also
========
