Mysql主从复制，遇到报错如下：

Last_IO_Error: Got fatal error 1236 from master when reading data from binary log: 'log event entry exceeded max_allowed_packet; Increase max_allowed_packet on master; the first event 'mysql-bin.001559' at 748770511, the last event read from 'mysql-bin.001559' at 748770511, the last byte read from 'mysql-bin.001559' at 748770530.'

问题原因：主从库这个参数不一致导致

登录主库，查询参数

sql
mysql> show variables like 'max_allowed_packet';
+--------------------+----------+
| Variable_name      | Value    |
+--------------------+----------+
| max_allowed_packet | 16777216 |
+--------------------+----------+
1 row in set (0.00 sec)

登录从库，查询参数

mysql> show variables like 'max_allowed_packet';
+--------------------+------------+
| Variable_name      | Value      |
+--------------------+------------+
| max_allowed_packet | 1073741824 |
+--------------------+------------+
1 row in set (0.00 sec)

解决办法：（修改主库参数和从库保持一致）

修改主库这个参数：

sql
mysql> set global max_allowed_packet=1073741824;

再次开启从库复制：

sql
mysql> start slave;
Query OK, 0 rows affected (0.01 sec)
 
mysql> show slave status\G;