Increasing MySQL Packet Maximum Size

MySQL / 1 min read

In the process of uploading a massive CSV file to my Django application my session data are getting pretty big. As a the result I’m getting these errors:

  • (1153, "Got a packet bigger than 'max_allowed_packet' bytes") and
  • (2006, 'MySQL server has gone away').

The second error is potentially unrelated.

After some research it became apparent that the source of the problem is my max_allowed_packet setting.

A quick check to find the current value:

mysql> SELECT @@max_allowed_packet;
+----------------------+
| @@max_allowed_packet |
+----------------------+
|             16777216 |
+----------------------+
1 row in set (0.00 sec)

That’s 16 Mb, but evidently not enough! It’s a simple matter to increase this limit. Just edit /etc/mysql/my.cnf (you’ll have to be root to do that!) and add the following:

[mysqld]
max_allowed_packet = 32M

Then restart MySQL.

# service mysql restart

Check that the limit has increased.

mysql> SELECT @@max_allowed_packet;
+----------------------+
| @@max_allowed_packet |
+----------------------+
|             33554432 |
+----------------------+
1 row in set (0.00 sec)

That solved the problem for me. If the problem persists then you might need to increase the limit further.