def METHOD_NAME(s):
    """Retrieve information about installed version of PostgreSQL."""
    if os.path.exists("../../../../src/bin/pg_config/pg_config"):
        f = os.popen("../../../../src/bin/pg_config/pg_config --%s" % s)
    else:
        """If a VPATH build, it might not be there.  Look other places"""
        """It should be the one in the path, because the makefile includes greenplum_path.sh """
        f = os.popen("pg_config --%s" % s)
    d = f.readline().strip()
    if f.close() is not None:
        raise Exception("pg_config tool is not available.")
    if not d:
        raise Exception("Could not get %s information." % s)
    return d