pg_close() closes down the non-persistent connection to a PostgreSQL database associated with the given connection resource. It returns TRUE, if connection is a valid connection resource, otherwise it return FALSE.
Note: pg_close() is not usually necessary, as non-persistent open links are automatically closed at the end of the script's execution. pg_close() will not close persistent links generated by pg_pconnect().
If there is open large object resource on the connection, do not close the connection before closing all large object resources.