pg_ctl - Starts, stops, or restarts postmaster
SYNOPSIS
pg_ctl start [ -w ] [ -D datadir ] [ -l filename ] [ -o
options ] [ -p path ]
pg_ctl stop [ -W ] [ -D datadir ] [ -m { s[mart] | f[ast]
| i[mmediate] } ]
pg_ctl restart [ -w ] [ -D datadir ] [ -m { s[mart] |
f[ast] | i[mmediate] } ] [ -o options ]
pg_ctl status [ -D datadir ]
DESCRIPTION
pg_ctl is a utility for starting, stopping, or restarting
postmaster(1), the PostgreSQL backend server, or display
ing the status of a running postmaster. Although the post
master can be started manually, pg_ctl encapulates tasks
such as redirecting log output, properly detaching from
the terminal and process group, and additionally provides
an option for controlled shut down.
In start mode, a new postmaster is launched. The server is
started in the background, the standard input attached to
/dev/null. The standard output and standard error are
either appended to a log file, if the -l option is used,
or are redirected to pg_ctl's standard output (not stan
dard error). If no log file is chosen, the standard output
of pg_ctl should be redirected to a file or piped to
another process, for example a log rotating program, oth
erwise the postmaster will write its output the the con
trolling terminal (from the background) and will not leave
the shell's process group.
In stop mode, the postmaster that is running on the speci
fied data directory is shut down. Three different shutdown
methods can be selected with the -m option: ``Smart'' mode
waits for all the clients to disconnect. This is the
default. ``Fast'' mode does not wait for clients to dis
connect. All active transactions will be rolled back.
``Immediate'' mode will abort without complete shutdown.
This will lead to a recovery run on restart. By the
default, stop mode waits for the shutdown to complete.
restart mode effectively executes a stop followed by a
start. This allows the changing of postmaster command line
options.
status mode checks whether a postmaster is running and if
so displays the PID and the command line options that were
used to invoke it.
-D datadir
Specifies the file system location of the database
files. If this is omitted, the environment variable
PGDATA is used.
-l 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 from other
users is disallowed by default.
-m mode
Specifies the shutdown mode. mode may be smart,
fast, or immediate, or the first letter of one of
these three.
-o options
Specifies options to be passed directly to postmas
ter.
The parameters are usually surrounded by single or
double quotes to ensure that they are passed
through as a group.
-p path
Specifies the location of the postmaster exe
cutable. By default the postmaster is taken from
the same directory as pg_ctl, or failing that, the
hard-wired installation directory. It is not neces
sary to use this option unless you are doing some
thing unusual and get errors that the postmaster
was not found.
-w Wait for the start or stutdown to complete. Times
out after 60 seconds. This is the default for shut
downs.
-W Do not wait for start or shutdown to complete. This
is the default for starts and restarts.
FILES
If the file postmaster.opts.default exists in the data
directory, the contents of the file will be passed as
options to the postmaster, unless overridden by the -o
option.
EXAMPLES
STARTING THE POSTMASTER
To start up postmaster:
$ pg_ctl start
postmaster comes up is:
$ pg_ctl -w start
For a postmaster using port 5433, and running without
fsync, use:
$ pg_ctl -o "-F -p 5433" start
STOPPING THE POSTMASTER
$ pg_ctl stop
stops postmaster. Using the -m switch allows one to con
trol how the backend shuts down.
RESTARTING THE POSTMASTER
This is almost equivalent to stopping the postmaster then
starting it again except that pg_ctl saves and reuses the
command line options that were passed to the previously
running instance. To restart postmaster in the simplest
form:
$ pg_ctl restart
To restart postmaster, waiting for it to shut down and to
come up:
$ pg_ctl -w restart
To restart using port 5433 and disabling fsync after
restarting:
$ pg_ctl -o "-F -p 5433" restart
SHOWING POSTMASTER STATUS
Here is a sample status output from pg_ctl:
$ pg_ctl status
pg_ctl: postmaster is running (pid: 13718)
Command line was:
/usr/local/pgsql/bin/postmaster '-D' '/usr/local/pgsql/data' '-p' '5433' '-B' '128'
This is the command line that would be invoked in restart
mode.
BUGS
Waiting for complete start is not a well-defined operation
and may fail if access control is set up in way that a
should be avoided.
SEE ALSO
postmaster(1), PostgreSQL Administrator's Guide
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