pgsql SQL监控，查询SQL执行情况

SELECT
    procpid,
    START,
    now() - START AS lap,
    current_query
FROM
    (
        SELECT
            backendid,
            pg_stat_get_backend_pid (S.backendid) AS procpid,
            pg_stat_get_backend_activity_start (S.backendid) AS START,
            pg_stat_get_backend_activity (S.backendid) AS current_query
        FROM
            (
                SELECT
                    pg_stat_get_backend_idset () AS backendid
            ) AS S
    ) AS S
WHERE
    current_query <> '<IDLE>'
ORDER BY
    lap DESC;