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.
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 32.1.1절 for more information.
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.
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.
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.
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 32.14절).
The options --dbname and --username can be used to avoid gratuitous error messages in the logs, but are not necessary for proper functionality.
$ 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