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=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.
-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--quietDo not display status message. This is useful when scripting.
-t seconds--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.
-U username--username=username
Connect to the database as the user username instead of the default.
-V--versionPrint the pg_isready version and exit.
-?--helpShow 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 35.15).
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:
$pg_isready/tmp:5432 - accepting connections$echo $?0
Running with connection parameters to a PostgreSQL cluster in startup:
$pg_isready -h localhost -p 5433localhost:5433 - rejecting connections$echo $?1
Running with connection parameters to a non-responsive PostgreSQL cluster:
$pg_isready -h someremotehostsomeremotehost:5432 - no response$echo $?2