MySQL PacketTooBigException: Fix the ‘Packet for query is too large’ Error

Problem

A project that previously ran fine suddenly fails with the error:

com.mysql.jdbc.PacketTooBigException: Packet for query is too large (1070 > 1024). You can change this value on the server by setting the max_allowed_packet variable.

Cause

The exception is triggered because MySQL's max_allowed_packet variable is set to a value smaller than the size of the query packet. In the example the packet size is 1070 KB while the configured limit is 1024 KB (1 M), so MySQL rejects the request.

Solution

Increase the max_allowed_packet limit:

Check the current setting with: show VARIABLES like '%max_allowed_packet%'; At runtime you can enlarge it, for example to 20 M, by executing:

set global max_allowed_packet = 2 * 1024 * 1024 * 10;

On Linux you can also edit the MySQL configuration file ( my.cnf) and add or modify the line: max_allowed_packet = 20M; After saving the file, restart the MySQL service: service mysql restart After the restart the new packet size limit takes effect and the error disappears.

Additional Knowledge

max_allowed_packet

defines the maximum size of a single data packet that the MySQL server and client can exchange. Setting it appropriately prevents large INSERT or UPDATE statements from being rejected.