qhb_ctl
qhb_ctl — initialize, start, stop, or control a QHB server
Synopsis
qhb_ctl qhb_bootstrap [-D datadir] [-s] [-o qhb_bootstrap-options ]
qhb_ctl init[db] [-D datadir] [-s] [-o initdb-options ]
qhb_ctl start [-D datadir] [-l filename] [-W] [-t seconds] [-s] [-o options] [-p path] [-c]
qhb_ctl stop [-D datadir] [-m s[mart] | f[ast] | i[mmediate] ] [-W] [-t seconds] [-s]
qhb_ctl restart [-D datadir] [-m s[mart] | f[ast] | i[mmediate] ] [-W] [-t seconds] [-s] [-o options] [-c]
qhb_ctl reload [-D datadir] [-s]
qhb_ctl status [-D datadir]
qhb_ctl promote [-D datadir] [-W] [-t seconds] [-s]
qhb_ctl logrotate [-D datadir] [-s]
qhb_ctl kill signal_name process_id
Description
qhb_ctl — is a utility for initializing a QHB database cluster, starting, stopping, or restarting the QHB database server (qhb Instance), or displaying the status of a running server. Although the server can be started manually, qhb_ctl encapsulates tasks such as redirecting log output and properly detaching from the terminal and process group. It also provides convenient options for controlled shutdown.
The qhb_bootstrap or init(initdb) mode creates a new QHB
database cluster, that is, a collection of databases that will be managed by a
single server instance. This mode invokes the qhb_bootstrap or initdb
command, respectively. See qhb_bootstrap and initdb for details.
start mode launches a new server. The server is started in the background, and
its standard input is attached to /dev/null. On Unix-like systems, by
default, the server's standard output and standard error are sent to qhb_ctl's
standard output (not standard error). The standard output of qhb_ctl should
then be redirected to a file or piped to another process such as a log rotating
program like rotatelogs; otherwise qhb will write
its output to the controlling terminal (from the background) and will not leave
the shell's process group. This default behavior can be changed by using -l
to append the server's output to a log file. Use of either -l or output
redirection is recommended.
stop mode shuts down the server that is running in the specified data directory.
Three different shutdown methods can be selected with the -m option. “Smart”
mode disallows new connections, then waits for all existing clients to disconnect.
If the server is in hot standby, recovery and streaming replication will be
terminated once all clients have disconnected. “Fast” mode (the default) does not
wait for clients to disconnect. All active transactions are rolled back and
clients are forcibly disconnected, then the server is shut down. “Immediate” mode
will abort all server processes immediately, without a clean shutdown. This choice
will lead to a crash-recovery cycle during the next server start.
restart mode effectively executes a stop followed by a start. This allows
changing the qhb command-line options, or changing configuration-file options
that cannot be changed without restarting the server. If relative paths were used
on the command line during server start, restart might fail unless qhb_ctl
is executed in the same current directory as it was during server start.
reload mode simply sends the qhb server process a
SIGHUP signal, causing it to reread its configuration files (qhb.conf,
qhb_hba.conf, etc.). This allows changing configuration-file options that
do not require a full server restart to take effect.
status mode checks whether a server is running in the specified data directory.
If it is, the server's PID and the command line options that were used to invoke
it are displayed. If the server is not running, qhb_ctl returns an exit
status of 3. If an accessible data directory is not specified, qhb_ctl
returns an exit status of 4.
promote mode commands the standby server that is running in the specified data
directory to end standby mode and begin read-write operations.
logrotate mode rotates the server log file. For details on how to use this
mode with external log rotation tools, see Section Log File Maintenance.
kill mode sends a signal to a specified process. Use --help to see a list
of supported signal names.
Options
-c
--core-files
Attempt to allow server crashes to produce core files, on platforms where this
is possible, by lifting any soft resource limit placed on core files. This is
useful in debugging or diagnosing problems by allowing a stack trace to be
obtained from a failed server process.
-D datadir
--pgdata=datadir
Specifies the file system location of the database configuration files. If this
option is omitted, the environment variable PGDATA is used.
-l filename
--log=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 is disallowed to
other users by default.
-m mode
--mode=mode
Specifies the shutdown mode. mode can be smart, fast, or immediate,
or the first letter of one of these three. If this option is omitted, fast is
the default.
-o options
--options=options
Specifies options to be passed directly to the qhb command. -o can be
specified multiple times, with all the given options being passed through.
The options should usually be surrounded by single or double quotes to ensure
that they are passed through as a group.
-o qhb_bootstrap-options
--options=qhb_bootstrap-options
Specifies options to be passed directly to the qhb_bootstrap command. -o
can be specified multiple times, with all the given options being passed through.
The qhb_bootstrap-options should usually be surrounded by single or double
quotes to ensure that they are passed through as a group.
-o initdb-options
--options=initdb-options
Specifies options to be passed directly to the initdb command. -o can be
specified multiple times, with all the given options being passed through.
The initdb-options should usually be surrounded by single or double quotes
to ensure that they are passed through as a group.
-p path
Specifies the location of the qhb executable. By
default the qhb executable is taken from the same
directory as qhb_ctl, or failing that, the hard-wired installation
directory. It is not necessary to use this option unless you are doing something
unusual and get errors that the qhb executable was
not found.
In qhb_bootstrap or init mode, this option analogously specifies the location
of the qhb_bootstrap or initdb executable, respectively.
-s
--silent
Print only errors, no informational messages.
-t seconds
--timeout=seconds
Specifies the maximum number of seconds to wait when waiting for an operation to
complete (see option -w). Defaults to the value of the PGCTLTIMEOUT
environment variable or, if not set, to 60 seconds.
-V
--version
Print the qhb_ctl version and exit.
-w
--wait
Wait for the operation to complete. This is supported for the modes start,
stop, restart, promote, and register, and is the default for those modes.
When waiting, qhb_ctl repeatedly checks the server's PID file, sleeping
for a short amount of time between checks. Startup is considered complete when
the PID file indicates that the server is ready to accept connections. Shutdown
is considered complete when the server removes the PID file. qhb_ctl
returns an exit code based on the success of the startup or shutdown.
If the operation does not complete within the timeout (see option -t), then
qhb_ctl exits with a nonzero exit status. But note that the operation
might continue in the background and eventually succeed.
-W
--no-wait
Do not wait for the operation to complete. This is the opposite of the option
-w.
If waiting is disabled, the requested action is triggered, but there is no
feedback about its success. In that case, the server log file or an external
monitoring system would have to be used to check the progress and success of the
operation.
-?
--help
Show help about qhb_ctl command line arguments, and exit.
If an option is specified that is valid, but not relevant to the selected operating mode, qhb_ctl ignores it.
Environment
PGCTLTIMEOUT
Default limit on the number of seconds to wait when waiting for startup or shutdown to complete. If not set, the default is 60 seconds.
PGDATA
Default data directory location.
Most qhb_ctl modes require knowing the data directory location; therefore, the -D option is required unless PGDATA is set.
For additional variables that affect the server, see qhb Instance.
Files
qhbmaster.pid
qhb_ctl examines this file in the data directory to determine whether the
server is currently running.
postmaster.opts
If this file exists in the data directory, qhb_ctl (in restart mode)
will pass the contents of the file as options to qhb, unless overridden by the
-o option. The contents of this file are also displayed in status mode.
Examples
Starting the Server
To start the server, waiting until the server is accepting connections:
$ qhb_ctl start
To start the server using port 5433, and running without fsync, use:
$ qhb_ctl -o "-F -p 5433" start
Stopping the Server
To stop the server, use:
$ qhb_ctl stop
The -m option allows control over how the server shuts down:
$ qhb_ctl stop -m smart
Restarting the Server
Restarting the server is almost equivalent to stopping the server and starting it again, except that by default, qhb_ctl saves and reuses the command line options that were passed to the previously-running instance. To restart the server using the same options as before, use:
$ qhb_ctl restart
But if -o is specified, that replaces any previous options. To restart using port 5433, disabling fsync upon restart:
$ qhb_ctl -o "-F -p 5433" restart
Showing the Server Status
Here is sample status output from qhb_ctl:
$ qhb_ctl status
qhb_ctl: server is running (PID: 13718)
/usr/local/qhb/bin/qhb "-D" "/var/lib/qhb/data" "-p" "5433" "-B" "128"
The second line is the command that would be invoked in restart mode.