Looks up a current parameter setting of the server.
Certain parameter values are reported by the server automatically at connection startup or whenever their values change. pg_parameter_status() can be used to interrogate these settings. It returns the current value of a parameter if known, or FALSE if the parameter is not known.
Parameters reported as of PostgreSQL 8.0 include server_version, server_encoding, client_encoding, is_superuser, session_authorization, DateStyle, TimeZone, and integer_datetimes. (server_encoding, TimeZone, and integer_datetimes were not reported by releases before 8.0.) Note that server_version, server_encoding and integer_datetimes cannot change after PostgreSQL startup.
PostgreSQL 7.3 or lower servers do not report parameter settings, pg_parameter_status() includes logic to obtain values for server_version and client_encoding anyway. Applications are encouraged to use pg_parameter_status() rather than ad hoc code to determine these values.
| Caution |
On a pre-7.4 PostgreSQL server, changing client_encoding via SET after connection startup will not be reflected by pg_parameter_status(). |
PostgreSQL database connection resource. When connection is not present, the default connection is used. The default connection is the last connection made by pg_connect() or pg_pconnect().
Possible param_name values include server_version, server_encoding, client_encoding, is_superuser, session_authorization, DateStyle, TimeZone, and integer_datetimes.
A string containing the value of the parameter, FALSE on failure or invalid param_name.