pg_ctl

As I promised, I have written a small program called "pg_ctl" to
start/stop/restart postmaster. I have committed into src/bin/pg_ctl.
Please remember to pull the latest postmaster.c.

o How to use

pg_ctl has three modes:

1. startup mode

pg_ctl [-w][-D database_dir][-p path_to_postmaster][-o "postmaster_opts"] start

start postmaster. If -w is specified, pg_ctl will block until database
is in the production mode. -D sets path to the database directory,
which overrides the environment variable $PGDATA. pg_ctl finds
postmaster.pid and other files under the directory. -p specifies the
path to postmaster. If -p is not given, default path (generated as
$(BINDIR)/postmaster while making pg_ctl from pg_ctl.sh) will be used.
If -o option is not given, pg_ctl will take options for postmaster
from $PGDATA/postamster.opts.default. Note that this file is not
currently installed by "make install." So you have to make it by hand
or could copy from postmaster.opts that is made once pg_ctl starts
postmaster. Sample postmaster.opts.default looks like:

postmaster
-S

or you could write it in one line:

postmaster -S

2. stop mode

pg_ctl [-w][-D database_dir][-m s[mart]|f[ast]|i[mmediate]] stop

stop postmaster. -m specifies database shutdown method. The default
is "-m smart".

3. restart mode

pg_ctl [-w][-D database_dir][-m s[mart]|f[ast]|i[mmediate]][-o "postmaster_opts"] restart

stop postmaster, then start it again. Options to start postmaster is
taken from $PGDATA/postmaster.opts unless -o is given.

4. status reporting mode

pg_ctl [-D database_dir] status

reports status of postmaster. Currently reported information is
relatively limited. Hopefully we could add the functionarity to report
more valuable info such as number of backend running.

o sample session

Here is an example session using pg_ctl:

$ pg_ctl stop # stop postmaster
postmaster successfully shut down.
$ pg_ctl stop # cannot stop postmaster if it is not running
pg_ctl: Can't find /usr/local/src/pgsql/current/data/postmaster.pid.
Is postmaster running?
$ pg_ctl start # start postmaster
postmaster successfully started up.
$ pg_ctl status # status report
$ pg_ctl status
pg_ctl: postmaster is running (pid: 736)
options are:
/usr/local/src/pgsql/current/bin/postmaster
-p 5432
-D /usr/local/src/pgsql/current/data
-B 64
-b /usr/local/src/pgsql/current/bin/postgres
-N 32
-S
$ pg_ctl restart # stop postmaster then start it again
Waiting for postmaster shutting down...done.
postmaster successfully shut down.
postmaster successfully started up.
$ pg_ctl status # see how the pid is different from before
pg_ctl: postmaster is running (pid: 761)
options are:
/usr/local/src/pgsql/current/bin/postmaster
-p 5432
-D /usr/local/src/pgsql/current/data
-B 64
-b /usr/local/src/pgsql/current/bin/postgres
-N 32
-S
$ pg_ctl -o "-S -B 1024 -N 128 -o -F" restart # restart with different options
Waiting for postmaster shutting down...done.
postmaster successfully shut down.
postmaster successfully started up.
$ pg_ctl status
pg_ctl: postmaster is running (pid: 961)
options are:
/usr/local/src/pgsql/current/bin/postmaster
-p 5432
-D /usr/local/src/pgsql/current/data
-B 1024
-b /usr/local/src/pgsql/current/bin/postgres
-N 128
-S
-o '-F'
--
Tatsuo Ishii