mysql数据库，查询记录时，为什么无法执行 for update？

Question

如下所示，我查询一条记录，然后主动上锁，但是总是失败，为什么？

mysql> select * from account where id = 5;
+----+-----------+---------+
| id | NAME      | balance |
+----+-----------+---------+
|  5 | zhangsang | 1000.00 |
+----+-----------+---------+
1 row in set (0.00 sec)

mysql> select * from account where id = 5 for update;
ERROR 1205 (HY000): Lock wait timeout exceeded; try restarting transaction

Answer 1

你的id是主键吗