Question

我试图创建会杀死所有睡眠连接的函数：

    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

但是当我运行它时，我得到了错误代码：1094。未知的线程ID：0＆＃39;。如果我把杀戮放入：

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

它会杀了什么，我犯错了？

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。

MySQL用于杀死睡眠连接的函数

1 个答案: