具体错误信息如下，如何解？

Lost connection to MySQL server at 'reading initial communication packet', system error: 111
错误位置
FILE: /data1/www/htdocs/135/it360/1/ThinkPHP/Library/Think/Db/Driver/Mysql.class.php 　LINE: 55
TRACE
#0 /data1/www/htdocs/135/it360/1/ThinkPHP/Library/Think/Db/Driver/Mysql.class.php(55): E('Lost connection...')
#1 /data1/www/htdocs/135/it360/1/ThinkPHP/Library/Think/Db.class.php(207): Think\Db\Driver\Mysql->connect(Array, 0)
#2 /data1/www/htdocs/135/it360/1/ThinkPHP/Library/Think/Db.class.php(163): Think\Db->multiConnect(false)
#3 /data1/www/htdocs/135/it360/1/ThinkPHP/Library/Think/Db/Driver/Mysql.class.php(92): Think\Db->initConnect(false)
#4 /data1/www/htdocs/135/it360/1/ThinkPHP/Library/Think/Db/Driver/Mysql.class.php(211): Think\Db\Driver\Mysql->query('SHOW COLUMNS FR...')
#5 /data1/www/htdocs/135/it360/1/ThinkPHP/Library/Think/Model.class.php(130): Think\Db\Driver\Mysql->getFields('t_user')
#6 /data1/www/htdocs/135/it360/1/ThinkPHP/Library/Think/Model.class.php(118): Think\Model->flush()
#7 /data1/www/htdocs/135/it360/1/ThinkPHP/Library/Think/Model.class.php(1298): Think\Model->_checkTableInfo()
#8 /data1/www/htdocs/135/it360/1/ThinkPHP/Library/Think/Model.class.php(95): Think\Model->db(0, '', true)
#9 /data1/www/htdocs/135/it360/1/ThinkPHP/Common/functions.php(521): Think\Model->__construct('User')
#10 /data1/www/htdocs/135/it360/1/Application/Home/Controller/UserController.class.php(25): D('User')
#11 [internal function]: Home\Controller\UserController->login_action()
#12 /data1/www/htdocs/135/it360/1/ThinkPHP/Library/Think/App.class.php(155): ReflectionMethod->invoke(object(Home\Controller\UserController))
#13 /data1/www/htdocs/135/it360/1/ThinkPHP/Library/Think/App.class.php(193): Think\App::exec()
#14 /data1/www/htdocs/135/it360/1/ThinkPHP/Library/Think/Think.class.php(120): Think\App::run()
#15 /data1/www/htdocs/135/it360/1/ThinkPHP/ThinkPHP.php(96): Think\Think::start()
#16 /data1/www/htdocs/135/it360/1/index.php(23): require('/data1/www/htdo...')
#17 {main}