Enter the mysql server
Running mysql command line
set global max_allowed_packet = 1048576*500
Exit mysql command line, and then log in again.
show VARIABLES like '%max_allowed_packet%';
View the next max_allowed_packet if successful edit
note: Tier 2, if the restart mysql service, value max_allowed_packet will revert to the default initial value, the value of the command line are not set.
https://blog.csdn.net/weixin_39561473/article/details/90213914