|PostgreSQL Reference Manual - Volume 3 - Server Administration Guide|
by The PostgreSQL Global Development Group
Paperback (6"x9"), 204 pages
RRP £13.95 ($24.95)
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3.5 Shutting Down the Server
There are several ways to shut down the database server. You control
the type of shutdown by sending different signals to the master
SIGTERM, the server disallows new connections, but lets existing sessions end their work normally. It shuts down only after all of the sessions terminate normally. This is the Smart Shutdown.
The server disallows new connections and sends all existing
SIGTERM, which will cause them to abort their current transactions and exit promptly. It then waits for the server processes to exit and finally shuts down. This is the Fast Shutdown.
This is the Immediate Shutdown, which
will cause the master
postgresprocess to send a
SIGQUITto all child processes and exit immediately, without properly shutting itself down. The child processes likewise exit immediately upon receiving
SIGQUIT. This will lead to recovery (by replaying the WAL log) upon next start-up. This is recommended only in emergencies.
pg_ctl program provides a convenient
interface for sending these signals to shut down the server.
Alternatively, you can send the signal directly using
The PID of the
postgres process can be
found using the
ps program, or from the file
‘postmaster.pid’ in the data directory. For
example, to do a fast shutdown:
$ kill -INT `head -1 /usr/local/pgsql/data/postmaster.pid`
Important: It is best not to use
SIGKILLto shut down the server. Doing so will prevent the server from releasing shared memory and semaphores, which may then have to be done manually before a new server can be started. Furthermore,
postgresprocess without letting it relay the signal to its subprocesses, so it will be necessary to kill the individual subprocesses by hand as well.
|ISBN 0954612043||PostgreSQL Reference Manual - Volume 3 - Server Administration Guide||See the print edition|