The REPLICATION SLAVE privilege should be granted to accounts that are used by slave servers to connect to the current server as their master. Without this privilege, the slave cannot request updates that have been made to databases on the master server.
这个用户用于:当slaver 在连自己的master的一个中间人。若该用户没有这个权限,slaver 将不能请求与master的数据同步更新