pg_isready
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## pg_isready

pg_isready — check the connection status of a PostgreSQL server

## Synopsis

`pg_isready` [`connection-option`...] [`option`...]

## Description

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.

## Options

`-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.

## 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 PostgreSQL utilities, also uses the environment variables supported by libpq (see Section 36.15).

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 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

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