MySQL exception: com mysql. jdbc. PacketTooBigException: Packet for query is too large(4223215 ＞ 4194304)

as a result of MySQL Of max_allowed_packet The setting is too small ,max_allowed_packet If not set , The default values are in different MySQL Different versions , Some versions default to 1M, Some versions default to 4M.

mysql According to the configuration file, it will limit server Accepted packet size . Sometimes big inserts and updates are max_allowed_packet Parameters limit , Result in failure .

1、 View the current configuration ：

Get into MYSQL

command ： mysql -uroot -p
Enter password:mysql password  

（ Or other database connection tools , Query or command-line interface can also ）

View the current configuration ：
Input show variables like '%max_allowed_packet%';

mysql>  show variables like '%max_allowed_pack%';

 2、1 Modify the configuration , What I set up here is 20M

stay MYSQL Internal input set global max_allowed_packet = 2*1024*1024*10;（20M）

mysql> set global max_allowed_packet = 10 * 1024 * 1024;

2、2( Profile persistent modification )：
vim /etc/my.cnf
[mysqld]
max_allowed_packet = 100M

Be careful ： After modifying the configuration file , Need to restart mysql Service to take effect

1、 Use service start-up ：service mysqld restart

2、 Use mysqld The script to start ：/etc/inint.d/mysqld restart

start-up ：# service mysqld start
stop it ：# service mysqld stop
restart ：# service mysqld restart