how to check and set max_allowed_packet mysql variable

Question

Possible Duplicate:
MySQL Error 1153 - Got a packet bigger than ‘max_allowed_packet’ bytes

Hi I am getting the error :

[1153] Got a packet bigger than 'max_allowed_packet'bytes

but I made no changes in my source code and the hosting states that they did not made any change in server settings.

I don't know what happened. But I am trying to find the reason.

so, how to check max_allowed_packet mysql variable by php script?

and is that possible to set it in source code?

Answer 1

max_allowed_packet is set in mysql config, not on php side

[mysqld]
max_allowed_packet=16M 

You can see it's curent value in mysql like this:

SHOW VARIABLES LIKE 'max_allowed_packet';

You can try to change it like this, but it's unlikely this will work on shared hosting:

SET GLOBAL max_allowed_packet=16777216;

You can read about it here http://dev.mysql.com/doc/refman/5.1/en/packet-too-large.html

EDIT

The [mysqld] is necessary to make the max_allowed_packet working since at least mysql version 5.5.

Recently setup an instance on AWS EC2 with Drupal and Solr Search Engine, which required 32M max_allowed_packet. It you set the value under [mysqld_safe] (which is default settings came with the mysql installation) mode in /etc/my.cnf, it did no work. I did not dig into the problem. But after I change it to [mysqld] and restarted the mysqld, it worked.