Stop a hot backup, if it was running, or error

        Return the last WAL file name and position that is required to
        gain consistency on the captured heap.

def run_stop_backup(cls):
        """
        Stop a hot backup, if it was running, or error

        Return the last WAL file name and position that is required to
        gain consistency on the captured heap.

        """
        def handler(popen):
            assert popen.returncode != 0
            raise UserException('Could not stop hot backup')

        return cls._dict_transform(psql_csv_run(
                "SELECT file_name, "
                "  lpad(file_offset::text, 8, '0') AS file_offset "
                "FROM pg_{0}file_name_offset("
                "  pg_stop_backup())".format(cls._wal_name()),
                error_handler=handler))