MySQL 4.1.1以降なら、SHOW SLAVE STATUSでSeconds_Behind_Masterというのが見られるそうで、これが遅延秒数の指標として使えるっぽい。 Seconds_Behind_Master This field is an indication of how “late” the slave is: When the slave SQL thread is actively running (processing updates), this field is the number of seconds that have elapsed since the timestamp of the most recent event on the master executed by that thread. When the SQL thread has cau