PG_CTL(1) PostgreSQL Server Applications PG_CTL(1)NAMEpg_ctl - start, stop, or restart a PostgreSQL server
SYNOPSISpg_ctl start [ -w ] [ -s ] [ -D datadir ] [ -l filename ]
[ -o options ] [ -p path ]
pg_ctl stop [ -W ] [ -s ] [ -D datadir ] [ -m s[mart] |
f[ast] | i[mmediate] ]
pg_ctl restart [ -w ] [ -s ] [ -D datadir ] [ -m s[mart]
| f[ast] | i[mmediate] ] [ -o options ]
pg_ctl reload [ -s ] [ -D datadir ]
pg_ctl status [ -D datadir ]
DESCRIPTIONpg_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 encapsulates tasks
such as redirecting log output, properly detaching from
the terminal and process group, and it provides convenient
options for controlled shutdown.
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 in 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 are rolled back and
clients are forcibly disconnected, then the database is
shut down. ``Immediate'' mode will abort all server pro-
cesses without clean shutdown. This will lead to a recov-
ery run on restart.
restart mode effectively executes a stop followed by a
start. This allows the changing of postmaster command line
options.
reload mode simply sends the postmaster a SIGHUP signal,
causing it to reread its configuration files (post-
gresql.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 postmaster is running and if
so displays the PID and the command line options that were
used to invoke it.
OPTIONS-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.
-s Only print errors, no informational messages.
-w Wait for the start or shutdown 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.
ENVIRONMENT
PGDATA Default data direction location
For others, see postmaster(1).
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.
NOTES
Waiting for complete start is not a well-defined operation
and may fail if access control is set up so that a local
client cannot connect without manual interaction. It
should be avoided.
EXAMPLES
STARTING THE POSTMASTER
To start up a postmaster:
$ pg_ctl start
An example of starting the postmaster, blocking until the
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 the postmaster. Using the -m switch allows one to
control how the backend shuts down.
RESTARTING THE POSTMASTER
This is almost equivalent to stopping the postmaster 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 postmaster in the sim-
plest 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.
SEE ALSOpostmaster(1), PostgreSQL Administrator's Guide
Application 2002-11-22 PG_CTL(1)
