gh-ost的延迟控制机制

root@sbtest04:46:19>select * from _yougege_ghc limit 10\G
*************************** 1. row ***************************
id: 1
last_update: 2019-02-13 16:46:38
hint: heartbeat
value: 2019-02-13T16:46:38.303648238+08:00