Согласно документации MySQL на max_allowed_packet
Некоторые программы, такие как mysql и mysqldump, позволяют вам изменять значение на стороне клиента, устанавливая max_allowed_packet в командной строке или в файле опций.
В командной строке, чтобы установить его на 512M, просто запустите клиент mysql с этим:
C:\>mysql -u... -p... Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 31 Server version: 5.5.12-log MySQL Community Server (GPL) Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved. Oracle is a registered trademark of Oracle Corporation and/or its affiliates. Other names may be trademarks of their respective owners. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. mysql> show variables like 'max_allowed_packet'; +--------------------+----------+ | Variable_name | Value | +--------------------+----------+ | max_allowed_packet | 16777216 | +--------------------+----------+ 1 row in set (0.00 sec) mysql> set max_allowed_packet=1024 * 1024 * 512; ERROR 1621 (HY000): SESSION variable 'max_allowed_packet' is read-only. Use SET GLOBAL to assign the value mysql> set global max_allowed_packet=1024 * 1024 * 512; Query OK, 0 rows affected (0.00 sec) mysql> show variables like 'max_allowed_packet'; +--------------------+----------+ | Variable_name | Value | +--------------------+----------+ | max_allowed_packet | 16777216 | +--------------------+----------+ 1 row in set (0.00 sec) mysql> exit Bye C:\>mysql -u... -p... Welcome to the MySQL monitor. Commands end with ; or \g. Your MySQL connection id is 32 Server version: 5.5.12-log MySQL Community Server (GPL) Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved. Oracle is a registered trademark of Oracle Corporation and/or its affiliates. Other names may be trademarks of their respective owners. Type 'help;' or '\h' for help. Type '\c' to clear the current input statement. mysql> show variables like 'max_allowed_packet'; +--------------------+-----------+ | Variable_name | Value | +--------------------+-----------+ | max_allowed_packet | 536870912 | +--------------------+-----------+ 1 row in set (0.00 sec) Вы должны установить это глобально. Вы не можете установить его локально.
Вам нужна привилегия SUPER для установки любой глобальной переменной.