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

Provided by: postgres-xc_1.1-2ubuntu2_amd64

NAME

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

SYNOPSIS


       pg_ctl init[db] [-s] [-D datadir] [-o initdb-options]

       pg_ctl start [-w] [-t seconds] [-s] [-D datadir] [-l filename] [-o options] [-p path] [-c] [-Z nodeopt]

       pg_ctl stop [-W] [-t seconds] [-s] [-D datadir] [-m s[mart] | f[ast] | i[mmediate]]

       pg_ctl restart [-w] [-t seconds] [-s] [-D datadir] [-c] [-m s[mart] | f[ast] | i[mmediate]] [-o options]
              [-Z nodeopt]

       pg_ctl reload [-s] [-D datadir]

       pg_ctl status [-D datadir]

       pg_ctl promote [-s] [-D datadir]

       pg_ctl kill signal_name process_id

       pg_ctl register [-N servicename] [-U username] [-P password] [-D datadir] [-S a[uto] | d[emand]] [-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. A database cluster is a collection of
databases that are managed by a single server instance. This mode invokes the initdb command. See
initdb(1) for details.

In start mode, a new server is launched. 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.

In stop mode, the server that is running in the specified data directory is shut down. Three different
shutdown methods can be selected with the -m option. “Smart” mode (the default) 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 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 will lead to a crash-recovery run
on the next restart.

restart mode effectively executes a stop followed by a start. This allows changing the postgres
command-line options.

reload mode simply sends the postgres process a SIGHUP signal, causing it to reread its configuration
files (postgresql.conf, pg_hba.conf, etc.). This allows changing of configuration-file options that do
not require a complete restart to take effect.

status mode checks whether a server is running in the specified data directory. If it is, the PID and the
command line options that were used to invoke it are displayed. If the server is not running, the process
returns an exit status of 3.

In promote mode, the standby server that is running in the specified data directory is commanded to exit
recovery and begin read-write operations.

kill mode allows you to send a signal to a specified process. This is particularly valuable for Microsoft
Windows which does not have a kill command. Use --help to see a list of supported signal names.

register mode allows you to register 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 allows you to unregister a system service on Microsoft Windows. This undoes the effects
of the register command.

OPTIONS

-c, --core-file
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 files. If this 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 is omitted, smart is used.

-o options
Specifies options to be passed directly to the postgres command.

The options should usually be surrounded by single or double quotes to ensure that they are passed
through as a group.

-o initdb-options
Specifies options to be passed directly to the initdb command.

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.

-Z nodeopt
Specifies to run node as a Coordinator, as a Datanode or in restore mode. nodeopt can be
respectively coordinator, datanode or restoremode.

With restore mode, you can import Postgres-XC's catalog data from other coordinator or datanode

-s, --silent
Print only errors, no informational messages.

-t, --timeout
The maximum number of seconds to wait when waiting for startup or shutdown to complete. The default
is 60 seconds.

-V, --version
Print the pg_ctl version and exit.

-w
Wait for the startup or shutdown to complete. Waiting is the default option for shutdowns, but not
startups. 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.

-W
Do not wait for startup or shutdown to complete. This is the default for start and restart modes.

-?, --help
Show help about pg_ctl command line arguments, and exit.

ENVIRONMENT

       PGDATA
           Default data directory location.

       pg_ctl, like most other PostgreSQL utilities, also uses the environment variables supported by libpq (see
       Section 32.14, “Environment Variables”, in the documentation). For additional server variables, see
       postgres(1).

       This command controls individual Coordinator or Datanode.

FILES

       postmaster.pid
           The existence of this file in the data directory is used to help pg_ctl determine if 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:

           $ pg_ctl start

       To start the server, waiting until the server is accepting connections:

           $ pg_ctl -w 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 fast

   Restarting the Server
       Restarting the server is almost equivalent to stopping the server and starting it again, except that
       pg_ctl saves and reuses the command line options that were passed to the previously running instance. To
       restart the server in the simplest form, use:

           $ pg_ctl restart

       To restart the server, waiting for it to shut down and restart:

           $ pg_ctl -w restart

       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"

       This is the command line that would be invoked in restart mode.