qhb_isready
qhb_isready — check the connection status of a QHB server
Synopsis
qhb_isready [connection-option...] [option...]
Description
qhb_isready is a utility for checking the connection status of a QHB database server. The exit status specifies the result of the connection check.
Options
-d dbname
--dbname=dbname
Specifies the name of the database to connect to. The dbname can be a
connection string. If so, connection string parameters will override any
conflicting command line options.
-h host
--host=host
Specifies the host name of the machine on which the server is running. If the
value begins with a slash, it is used as the directory for the Unix domain socket.
-p port
--port=port
Specifies the TCP port or local Unix domain socket file extension on which the
server is listening for connections. Defaults to the value of the PGPORT
environment variable or, if not set, to the port specified at compile time,
usually 5432.
-q
--quiet
Do not display status message. This is useful when scripting.
-t seconds
--timeout=seconds
The maximum number of seconds to wait when attempting connection before returning
that the server is not responding. Setting to 0 disables. The default is 3 seconds.
-U username
--username=username
Connect to the database as the user username instead of the default.
-V
--version
Print the qhb_isready version and exit.
-?
--help
Show help about qhb_isready command line arguments, and exit.
Exit Status
qhb_isready returns 0 to the shell if the server is accepting connections normally, 1 if the server is rejecting connections (for example during startup), 2 if there was no response to the connection attempt, and 3 if no attempt was made (for example due to invalid parameters).
Environment
qhb_isready, like most other QHB utilities, also uses the environment variables supported by libpq (see Section Environment Variables).
The environment variable PG_COLOR specifies whether to use color in diagnostic messages. Possible values are always, auto and never.
Notes
It is not necessary to supply correct user name, password, or database name values to obtain the server status; however, if incorrect values are provided, the server will log a failed connection attempt.
Examples
Standard usage:
$ qhb_isready
/tmp:5432 - accepting connections
$ echo $?
0
Running with connection parameters to a QHB cluster in startup:
$ qhb_isready -h localhost -p 5433
localhost:5433 - rejecting connections
$ echo $?
1
Running with connection parameters to a non-responsive QHB cluster:
$ qhb_isready -h someremotehost
someremotehost:5432 - no response
$ echo $?
2