【发布时间】：2017-12-10 12:31:42
【问题描述】：
我有一个非常简单的表格：
CREATE TABLE `d` (
`id` int(11) DEFAULT NULL,
UNIQUE KEY `id` (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8
没有记录：
select * from d;
Empty set (0,01 sec)
然后我尝试在不同的会话中打开两个事务：
第 1 场会议：
begin;
Query OK, 0 rows affected (0,00 sec)
select * from d where id = 100 for update;
Empty set (0,00 sec)
第 2 场会议：
begin;
Query OK, 0 rows affected (0,00 sec)
select * from d where id = 700 for update;
Empty set (0,00 sec)
现在我尝试在 会话 #2 中插入新记录并且会话“冻结”：
insert into d values (700);
当我尝试在 Session #1 中做同样的事情（使用另一个 id 字段）时，它会崩溃：
insert into d values (100); --> ERROR 1213 (40001): Deadlock found when trying to get lock; try restarting transaction in Session #1
insert into d values (700); --> Query OK, 1 row affected (4,08 sec) in Session #2
如何解决死锁？ InnoDB 状态为：
------------------------
LATEST DETECTED DEADLOCK
------------------------
2017-07-06 15:59:25 0x70000350d000
*** (1) TRANSACTION:
TRANSACTION 43567, ACTIVE 15 sec inserting
mysql tables in use 1, locked 1
LOCK WAIT 3 lock struct(s), heap size 1136, 2 row lock(s), undo log entries 1
MySQL thread id 4, OS thread handle 123145358217216, query id 89 localhost root update
insert into d values (700)
*** (1) WAITING FOR THIS LOCK TO BE GRANTED:
RECORD LOCKS space id 126 page no 4 n bits 72 index id of table `trx`.`d` trx id 43567 lock_mode X insert intention waiting
Record lock, heap no 1 PHYSICAL RECORD: n_fields 1; compact format; info bits 0
0: len 8; hex 73757072656d756d; asc supremum;;
*** (2) TRANSACTION:
TRANSACTION 43568, ACTIVE 7 sec inserting
mysql tables in use 1, locked 1
3 lock struct(s), heap size 1136, 2 row lock(s), undo log entries 1
MySQL thread id 3, OS thread handle 123145357938688, query id 90 localhost root update
insert into d values (100)
*** (2) HOLDS THE LOCK(S):
RECORD LOCKS space id 126 page no 4 n bits 72 index id of table `trx`.`d` trx id 43568 lock_mode X
Record lock, heap no 1 PHYSICAL RECORD: n_fields 1; compact format; info bits 0
0: len 8; hex 73757072656d756d; asc supremum;;
*** (2) WAITING FOR THIS LOCK TO BE GRANTED:
RECORD LOCKS space id 126 page no 4 n bits 72 index id of table `trx`.`d` trx id 43568 lock_mode X insert intention waiting
Record lock, heap no 1 PHYSICAL RECORD: n_fields 1; compact format; info bits 0
0: len 8; hex 73757072656d756d; asc supremum;;
*** WE ROLL BACK TRANSACTION (2)
【问题讨论】：
-
你想解决什么问题 :) ？这是想知道为什么mysql正在做它正在做的事情吗？还是有您想要解决的具体问题？
-
我尝试解决我的应用程序中的死锁（当然表 d 不是真实的）。为了更清楚起见，将此添加到问题中。
标签： mysql concurrency transactions locking