56,912
社区成员




mysql> begin;
Query OK, 0 rows affected (0.00 sec)
mysql> select * from t for update;
+----+------+
| id | col2 |
+----+------+
| 1 | wa |
| 2 | ch |
+----+------+
2 rows in set (0.00 sec)
mysql>
会话2:
mysql> begin;
Query OK, 0 rows affected (0.00 sec)
mysql> update t set col2='ww' where id=1;
update操作会hang在那里,与需求相符。直到出现:ERROR 1205 (HY000): Lock wait timeout exceeded; try restarting transaction
这时如果会话1,执行commit操作, 会话2的update操作立即完成。