MYSQL Packet for query is too large (12054240 > 4194304). You can change this value on the server by setting the max_allowed_packet' variable.
https://www.cnblogs.com/grasshopper/p/7098987.html
mysql max_allowed_packet查询和修改 - 水晶糖 - 博客园
https://www.cnblogs.com/weiwang/p/5404906.html
写入MySQL报错超出 max_allowed_packet 的问题 - sunny05296的博客 - CSDN博客
https://blog.csdn.net/sunny05296/article/details/80446944
max_allowed_packet参数 - 简书
https://www.jianshu.com/p/629685b97030