pg_isready man page
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
Specifies the name of the database to connect to.
If this parameter contains an = sign or starts with a valid URI prefix (postgresql:// or postgres://), it is treated as a conninfo string. See Section 33.1.1 for more information.
- -h 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
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.
Do not display status message. This is useful when scripting.
- -t 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
Connect to the database as the user username instead of the default.
Print the pg_isready version and exit.
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).
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.
$ pg_isready /tmp:5432 - accepting connections $ echo $? 0
Running with connection parameters to a PostgreSQL cluster in startup:
$ pg_isready -h localhost -p 5433 localhost:5433 - rejecting connections $ echo $? 1
Running with connection parameters to a non-responsive PostgreSQL cluster:
$ pg_isready -h someremotehost someremotehost:5432 - no response $ echo $? 2