2013 - Lost connection to MySQL server during query

select c.topics_id, cd.topics_name, c.parent_id from topics c, topics_description cd where c.topics_status = '1' and c.parent_id = '0' and c.group_permission_1=1 and c.topics_id = cd.topics_id and cd.language_id='1' order by sort_order, cd.topics_name

[XT SQL Error]

2006 - MySQL server has gone away

select count(*) as total from sessions where sesskey = 'qg48scd9ol5atdh659m0456lq7'

[XT SQL Error]