https://blog.csdn.net/niqinwen/article/details/8693044
导入数据库的时候 SQLyog 报错了
Error Code: 2006 – MySQL server has gone away
搜了下，说是max_allowed_packet （MySQL的一个参数）设置的值不够大。
那我改下就行了 嘿嘿
In Windows:
In the MySQL server installation directory,
in my.ini file, add the following line under [mysqld] in SERVER SECTION.
max_allowed_packet = 16M
In Linux:
Copy the my-xxx.cnf file from /usr/share/mysql to /etc as my.cnf
xxx can be small, medium, large, huge … depending on the requirement.
$ cp /usr/share/mysql/my-xxx.cnf /etc/my.cnf
In the my.cnf file, change the default
max_allowed_packet = 1M
to
max_allowed_packet = 16M
Save the file and restart MySQL server.
今天导入.sql文件时出现了Error Code: 2006 – MySQL server has gone away错误，原来是导入的sql文件大于系统默认的max_allowed_packet的值，查了很多修改配置文件的，但是没有找到my.cfg文件，修改其他文件不管用，所以直接使用sql语句来修改：
SET GLOBAL max_allowed_packet=67108864;
这个挺好使的，改完之后不用重启服务，直接好使了
原文地址：https://www.cnblogs.com/kccdzz/p/9426895.html