pg_isready
pg_isready — check the connection status of a Postgres Pro server
Synopsis
pg_isready [connection-option...] [option...]
Description
pg_isready is a utility for checking the connection status of a Postgres Pro database server. The exit status specifies the result of the connection check.
Options
-ddbname--dbname=dbnameSpecifies the name of the database to connect to. The
dbnamecan be a connection string. If so, connection string parameters will override any conflicting command line options.-hhostname--host=hostnameSpecifies 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.
-pport--port=portSpecifies the TCP port or the local Unix-domain socket file extension on which the server is listening for connections. Defaults to the value of the
PGPORTenvironment variable or, if not set, to the port specified at compile time, usually 5432.-q--quietDo not display status message. This is useful when scripting.
-tseconds--timeout=secondsThe 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.
-Uusername--username=usernameConnect to the database as the user
usernameinstead of the default.-V--versionPrint the pg_isready version and exit.
-?--helpShow help about pg_isready command line arguments, and exit.
Exit Status
pg_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
pg_isready, like most other Postgres Pro utilities, also uses the environment variables supported by libpq (see Section 35.14).
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:
$pg_isready/tmp:5432 - accepting connections$echo $?0
Running with connection parameters to a Postgres Pro cluster in startup:
$pg_isready -h localhost -p 5433localhost:5433 - rejecting connections$echo $?1
Running with connection parameters to a non-responsive Postgres Pro cluster:
$pg_isready -h someremotehostsomeremotehost:5432 - no response$echo $?2