MySQL 的存储过程中请求一个锁对象

mysql>
mysql> delimiter $$
mysql>
mysql> CREATE PROCEDURE myProc()
    -> BEGIN
    ->     DECLARE lock_result INT;
    ->     IF get_lock('sp_critical_section_lock',60) THEN
    ->        /* This block can only be run by one user at a time*/
    ->        SELECT 'got lock';
    ->        /* Critical code here */
    ->       SET lock_result=release_lock('sp_critical_section_lock');
    ->     ELSE
    ->        SELECT 'failed to acquire lock';
    ->        /* Error handling here */
    ->     END IF;
    -> END$$
Query OK, 0 rows affected (0.00 sec)
 
mysql>
mysql> delimiter ;
mysql> call myProc();
+----------+
| got lock |
+----------+
| got lock |
+----------+
1 row in set (0.02 sec)
 
Query OK, 0 rows affected (0.02 sec)
 
mysql>
mysql> drop procedure myProc;
Query OK, 0 rows affected (0.00 sec)
 
mysql>
mysql>