Warning: PDO::__construct(): [2002] No such file or directory (trying to connect via unix:///tmp/mysql.sock) in /www/wwwroot/m.yqxxs.com/include/db.php on line 3

Fatal error: Uncaught exception 'Exception' with message 'SQLSTATE[HY000] [2002] No such file or directory' in /www/wwwroot/m.yqxxs.com/include/db.php:3
Stack trace:
#0 /www/wwwroot/m.yqxxs.com/include/function.php(21): Db->__construct(Array)
#1 /www/wwwroot/m.yqxxs.com/include/book.php(8): D()
#2 /www/wwwroot/m.yqxxs.com/action/down.php(8): bookInfo(37768)
#3 /www/wwwroot/m.yqxxs.com/index.php(16): include('/www/wwwroot/m....')
#4 {main}
  thrown in /www/wwwroot/m.yqxxs.com/include/db.php on line 3