MySQL函数杀死熟睡的连接

Question

我试图创建函数，将杀死所有沉睡的连接：

CREATE DEFINER=`user`@`%` FUNCTION `kill_sleepers`() RETURNS int(11) 
BEGIN 
    DECLARE Id, result INT; 
    DECLARE done INT DEFAULT FALSE; 
    DECLARE sleepers CURSOR FOR SELECT Id FROM INFORMATION_SCHEMA.processlist where COMMAND = 'Sleep'; 
    DECLARE CONTINUE HANDLER FOR NOT FOUND SET done = TRUE; 

    SET result = 0; 
    OPEN sleepers; 

    read_loop: LOOP 
     FETCH sleepers INTO Id; 
     IF done THEN 
      LEAVE read_loop; 
     END IF; 
     kill Id; 
      SET result = result + 1; 
    END LOOP; 

    CLOSE sleepers;  
    RETURN result; 
END 

但是当我运行它，我得到了“错误代码：1094未知线程ID：0”。如果我把杀入：

IF Id != 0 THEN 
    kill Id; 
    SET result = result + 1; 
END IF; 

它会杀了什么，我犯了什么错误？

Answer 1

DROP FUNCTION KILL_SLEEPERS; 
DELIMITER $$ 
CREATE FUNCTION KILL_SLEEPERS() 
    RETURNS INT READS SQL DATA 
    BEGIN 
     DECLARE DONE INT DEFAULT FALSE; 
     DECLARE VAR_ID INT; 
     DECLARE ITER INT; 
     DECLARE SLEEPERS CURSOR FOR SELECT ID FROM INFORMATION_SCHEMA.PROCESSLIST WHERE COMMAND = 'SLEEP'; 
     DECLARE CONTINUE HANDLER FOR NOT FOUND SET DONE = TRUE; 
     SET ITER = 0; 
     OPEN SLEEPERS; 

     READ_LOOP: LOOP 
      FETCH SLEEPERS INTO VAR_ID; 
      IF DONE THEN 
       LEAVE READ_LOOP; 
      END IF; 
       KILL VAR_ID; 
      SET ITER = ITER + 1; 
     END LOOP; 
    CLOSE SLEEPERS; 
    RETURN ITER; 
END; 
$$ 
DELIMITER ; 

SELECT KILL_SLEEPERS(); 

试试上面的代码。

我刚刚将变量名称从ID更改为VAR_ID。