postgresql关闭服务器的方法：
[postgres@localhost ~]$ pg_ctl stop waiting for server to shut down.... done server stopped
pg_ctl stop
$ pg_ctl --help Usage: pg_ctl stop [-W] [-t SECS] [-D DATADIR] [-s] [-m SHUTDOWN-MODE] Common options: -D, --pgdata=DATADIR location of the database storage area -s, --silent only print errors, no informational messages -t, --timeout=SECS seconds to wait when using -w option -V, --version output version information, then exit -w wait until operation completes -W do not wait until operation completes Options for stop or restart: -m, --mode=MODE MODE can be "smart", "fast", or "immediate" Shutdown modes are: smart quit after all clients have disconnected fast quit directly, with proper shutdown immediate quit without complete shutdown; will lead to recovery on restart Allowed signal names for kill: ABRT HUP INT QUIT TERM USR1 USR2
pg_ctl stop -m smart
SIGTERM "Smart"模式等待所有客户端断开连接以及任何在线备份结束。如果该服务器是热备，一旦所有的客户端已经断开连接，恢复和流复制将被终止。
pg_ctl stop -m fast
SIGINT "Fast"模式（默认）不会等待客户端断开连接并且将终止进行中的在线备份。所有活动事务都被回滚并且客户端被强制断开连接，然后服务器被关闭。
pg_ctl stop -m immediate
SIGQUIT "Immediate"模式将立刻中止所有服务器进程，而不是做一次干净的关闭。这将导致下一次重启时进行一次崩溃恢复。
