pg_isready — check the connection status of a PostgreSQL server
pg_isready [connection-option...] [option...]
pg_isready is a utility for checking the connection status of a PostgreSQL database server. The exit status specifies the result of the connection check.
-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 hostname
--host=hostname
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 the 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 pg_isready version and exit.
-?
--help
Show help about pg_isready command line arguments, and exit.
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).
pg_isready, like most other PostgreSQL utilities, also uses the environment variables supported by libpq (see Section 33.14).
The environment variable PG_COLOR specifies whether to use color in diagnostic messages. Possible values are always, auto and never.
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.
Standard Usage:
Running with connection parameters to a PostgreSQL cluster in startup:
Running with connection parameters to a non-responsive PostgreSQL cluster: