MYSQL事务未回滚

Question

我在Mysql 5.1.73-cll中有以下存储过程：

BEGIN
   DECLARE finished1 INTEGER DEFAULT 0;
   DECLARE cursor1 CURSOR FOR SELECT ... FROM table1 WHERE Id= 1;
   DECLARE CONTINUE HANDLER FOR NOT FOUND SET finished1 = 1;
   DECLARE EXIT HANDLER FOR SQLEXCEPTION
      BEGIN
        CALL Debug('SQLEXCEPTION');
        ROLLBACK;
        CALL Debug('Rollback executed');
     END;
   START TRANSACTION;
      INSERT INTO table2(...)  VALUES (...);  /* Statement 1*/
      OPEN cursor1;
  label1: LOOP
         FETCH cursor1 INTO var1, var2;
         IF finished1 = 1 THEN
            INSERT INTO table1(...) VALUES (...);  /* Statement 2*/
            LEAVE label1;
         END IF;
         UPDATE table1 SET ... WHERE Id=1;     /* Statement 3*/
         LEAVE label1;
         END LOOP label1;        
      CLOSE cursor1;
   COMMIT;
END

当我（故意）在语句3中引入SQL错误，并确保finished1 = 0时，我希望回滚语句1，但事实并非如此。 通过我的Debug过程，我知道执行了Rollback语句。所有表都是InnoDb。 我做错了什么？