SQLSTATE[HY000] [1040] Too many connections

FILE: /data/website/beijingsmart.com/Core/Library/Think/Db/Driver.class.php 　LINE: 109

#0 /data/website/beijingsmart.com/Core/Library/Think/Db/Driver.class.php(109): E('SQLSTATE[HY000]...')
#1 /data/website/beijingsmart.com/Core/Library/Think/Db/Driver.class.php(1064): Think\Db\Driver->connect()
#2 /data/website/beijingsmart.com/Core/Library/Think/Db/Driver/Mysql.class.php(47): Think\Db\Driver->initConnect(true)
#3 /data/website/beijingsmart.com/Core/Library/Think/Model.class.php(134): Think\Db\Driver\Mysql->getFields('y_config')
#4 /data/website/beijingsmart.com/Core/Library/Think/Model.class.php(122): Think\Model->flush()
#5 /data/website/beijingsmart.com/Core/Library/Think/Model.class.php(1434): Think\Model->_checkTableInfo()
#6 /data/website/beijingsmart.com/Core/Library/Think/Model.class.php(97): Think\Model->db(0, '', true)
#7 /data/website/beijingsmart.com/Core/Common/functions.php(621): Think\Model->__construct('config', '', '')
#8 /data/website/beijingsmart.com/Application/Home/Controller/CommonController.class.php(16): M('config')
#9 /data/website/beijingsmart.com/Application/Home/Controller/CommonController.class.php(11): Home\Controller\CommonController->config()
#10 /data/website/beijingsmart.com/Core/Library/Think/Controller.class.php(41): Home\Controller\CommonController->_initialize()
#11 /data/website/beijingsmart.com/Core/Common/functions.php(681): Think\Controller->__construct()
#12 /data/website/beijingsmart.com/Core/Library/Think/App.class.php(89): controller('Example', '')
#13 /data/website/beijingsmart.com/Core/Library/Think/App.class.php(202): Think\App::exec()
#14 /data/website/beijingsmart.com/Core/Library/Think/Think.class.php(120): Think\App::run()
#15 /data/website/beijingsmart.com/Core/Core.php(101): Think\Think::start()
#16 /data/website/beijingsmart.com/wwwroot/index.php(22): require('/data/website/b...')
#17 {main}