PDO::ERRMODE_EXCEPTION,        );          $pdo=new PDO("mysql:host=localhost;dbname=pan","root","xxxx",$opts);        $pdo->query('set names utf8');        $sth=$pdo->prepare("select sleep(20) from texts where title like '%测试%'");        $sth->execute(array("title"=>"测试"));        $res=$sth->fetchAll(PDO::FETCH_ASSOC);        print_r($res);}catch(Exception $e){            //2. code不是整型，如果不进行处理，会在此处报Fatal的500错误        //Fatal error: Uncaught Error: Wrong parameters for MyDbException([string $message [, long $code [, Throwable $previous = NULL]]])        throw new MyDbException($e->getMessage(),intval($e->getCode()));}class MyDbException extends Exception{}echo "1111111";/*3.测试慢查询        3.1 sql语句中使用 select sleep(20) from        3.2 开启慢查询日志：                配置文件：/etc/mysql/mysql.conf.d/mysqld.cnf                slow_query_log = ON                slow_query_log_file = /usr/local/mysql/data/slow.log                long_query_time = 1                show variables like 'slow_query%';                show variables like 'long_query_time';        3.3 kill掉mysql的连接线程                show full processlist;                kill id号*/