官网说明：
Normally, a slave does not log to its own binary log any updates that are received from a master server. This option tells the slave to log the updates performed by its SQL thread to its own binary log. For this option to have any effect, the slave must also be started with the
A -> B -> C
Here, A serves as the master for the slave B, and B serves as the master for the slave C. For this to work, B must be both a master and a slave. You must start both A and B with
通常情况，从服务器从主服务器接收到的更新不记入它的二进制日志。该选项告诉从服务器将其SQL线程执行的更新记入到从服务器自己的二进制日志。为了使该选项生效，还必须用
A -> B -> C
也就是说，A为从服务器B的主服务器，B为从服务器C的主服务器。为了能工作，B必须既为主服务器又为从服务器。你必须用
这样来自A的事务能记录在B的二进制文件中，再传送给C