2013 - Lost connection to MySQL server during query

update whos_online set customer_id = '', full_name = 'Guest', ip_address = '54.226.181.106', time_last_click = '1518917556', last_page_url = '/product_info.php?info=p255_----------------------------NO-L59.html&XTCsid=0b0c1916s4td4f51q0eom5l6b7' where session_id = '0b0c1916s4td4f51q0eom5l6b7'

[XT SQL Error]

2006 - MySQL server has gone away

select count(*) as total from sessions where sesskey = '0b0c1916s4td4f51q0eom5l6b7'

[XT SQL Error]