2013 - Lost connection to MySQL server during query

update whos_online set customer_id = '', full_name = 'Guest', ip_address = '18.223.131.214', time_last_click = '1716964353', last_page_url = '/pub/product_info.php?XTCsid=56c9dd1a945470a5baa4c98daa7032dc&info=p39328_WRS319370.html' where session_id = '56c9dd1a945470a5baa4c98daa7032dc'

[XT SQL Error]

2006 - MySQL server has gone away

select count(*) as total from sessions where sesskey = '56c9dd1a945470a5baa4c98daa7032dc'

[XT SQL Error]