2013 - Lost connection to MySQL server during query

update whos_online set customer_id = '', full_name = 'Guest', ip_address = '18.118.27.125', time_last_click = '1717984167', last_page_url = '/pub/product_info.php?XTCsid=c10d43de454e964b2d916762600cf2ef&info=p43242_606-1271336987.html' where session_id = 'c10d43de454e964b2d916762600cf2ef'

[XT SQL Error]

2006 - MySQL server has gone away

select count(*) as total from sessions where sesskey = 'c10d43de454e964b2d916762600cf2ef'

[XT SQL Error]