MySQL server has gone away

The MySQL server has gone away (error 2006) has two main causes and solutions:

• Server timed out and closed the connection. 
• To fix, check that “wait_timeout” mysql variable in your my.cnf configuration file is large enough.
• Server dropped an incorrect or too large packet. If mysqld gets a packet that is too large or incorrect, it assumes that something has gone wrong with the client and closes the connection. 
• To fix, you can increase the maximal packet size limit “max_allowed_packet” in my.cnf file. eg. set max_allowed_packet = 128M, restart MySQL Server.