MySQL max_allowed_packet: packet too large

1. About the error
2. Why do I see this error
3. Solution
4. Raise the limit for the running server
5. Set it for an import
6. Check the current value

#About the error

You'll hit one of these:

ERROR 1153 (08S01): Got a packet bigger than 'max_allowed_packet' bytes
ERROR 2006 (HY000): MySQL server has gone away

When a client or the server receives a single packet larger than max_allowed_packet, it rejects it and drops the connection, which often surfaces as the misleading "server has gone away" message.

#Why do I see this error

• Importing a database dump that contains very large multi-row INSERT statements.
• Storing large BLOB / TEXT values, like images or big JSON columns.
• A bulk insert that builds one enormous query.

#Solution

#Raise the limit for the running server

You can set it at runtime without a restart (the value is in bytes, this is 256 MB):

SET GLOBAL max_allowed_packet = 268435456;

A runtime change is reset on restart, so make it permanent in my.cnf (/etc/mysql/my.cnf or a file under /etc/mysql/conf.d/):

[mysqld]
max_allowed_packet = 256M

Then restart MySQL:

systemctl restart mysql

#Set it for an import

When the error happens during an import, the client also has its own limit. Pass it on the command line so both sides agree:

mysql --max_allowed_packet=256M -u forge -p my_app < dump.sql

See importing a database from the command line for the full import workflow.

#Check the current value

To see where it's set right now:

SHOW VARIABLES LIKE 'max_allowed_packet';

If you regularly export and re-import large databases, it's worth setting a generous value on both the source and destination so dumps move cleanly. See exporting a database from the command line.