我观察到我的数据库有非常奇怪的行为。 我有一个小表(大约 300 行),其中一个字段不断更新。
我在那里遇到了很多死锁 - 表的更新使同一个表的类似更新陷入死锁(U 锁与 X 锁)。
所以我决定删除聚簇索引(所以表现在没有任何索引)来修复死锁。但这没有帮助,现在我遇到了 U 和 X 锁定模式之间的僵局。
所以一张表,没有索引,2个session更新一张表
受害者
update dbo.MyNumber set
@nextno = nextno = nextno + 1
where [type] = @type
and yearid = @yearid
获胜查询:
update dbo.MyNumber set
@nextno = nextno = nextno + 1
where [type] = @TYPE
and yrclosedyn = 0
行肯定不同,但页面是一样的。
这怎么可能?也许它与锁升级有关,或者...?
我非常感谢任何建议。
提前致谢 迈克
死锁 XML:
<deadlock-list>
<deadlock victim="process6c492e8">
<process-list>
<process id="processb6a988" taskpriority="0" logused="1848" waitresource="RID: 5:1:127478:16" waittime="3478" ownerId="17153439" transactionname="user_transaction" lasttranstarted="2012-12-18T12:31:40.147" XDES="0xffffffff89482258" lockMode="U" schedulerid="7" kpid="4248" status="suspended" spid="98" sbid="0" ecid="0" priority="0" transcount="2" lastbatchstarted="2012-12-18T12:31:49.913" lastbatchcompleted="2012-12-18T12:31:49.913" clientapp="PenAIR" hostname="S16047425" hostpid="9300" loginname="sa" isolationlevel="read committed (2)" xactid="17153439" currentdb="5" lockTimeout="4294967295" clientoption1="673185824" clientoption2="128056">
<executionStack>
<frame procname="MYDATABASE.dbo.MyStoredProcedure" line="92" stmtstart="9062" stmtend="9388" sqlhandle="0x030005002d15a05e58b5710016a100000100000000000000">
UPDATE dbo.MyNumber Set
@NEXTNO = NEXTNO = NEXTNO + 1
WHERE (TYPE = @TYPE) AND (YRCLOSEDYN = 0) </frame>
</executionStack>
<inputbuf>
Proc [Database Id = 5 Object Id = 1587549485] </inputbuf>
</process>
<process id="process6c492e8" taskpriority="0" logused="192" waitresource="RID: 5:1:127478:20" waittime="8252" ownerId="17153562" transactionname="user_transaction" lasttranstarted="2012-12-18T12:31:45.140" XDES="0x6583b1e0" lockMode="U" schedulerid="13" kpid="19824" status="suspended" spid="143" sbid="0" ecid="0" priority="0" transcount="2" lastbatchstarted="2012-12-18T12:31:45.140" lastbatchcompleted="2012-12-18T12:31:45.140" clientapp="PenAIR" hostname="S16047425" hostpid="4760" loginname="sa" isolationlevel="read committed (2)" xactid="17153562" currentdb="5" lockTimeout="4294967295" clientoption1="673185824" clientoption2="128056">
<executionStack>
<frame procname="MYDATABASE.dbo.MyStoredProcedure" line="92" stmtstart="9062" stmtend="9388" sqlhandle="0x030005002d15a05e58b5710016a100000100000000000000">
UPDATE dbo.MyNumber Set
@NEXTNO = NEXTNO = NEXTNO + 1
WHERE ([TYPE] = @TYPE) AND (YRCLOSEDYN = 0) </frame>
</executionStack>
<inputbuf>
Proc [Database Id = 5 Object Id = 1587549485] </inputbuf>
</process>
</process-list>
<resource-list>
<ridlock fileid="1" pageid="127478" dbid="5" objectname="MYDATABASE.dbo.MyNumber" id="lock464f2640" mode="X" associatedObjectId="72057594131120128">
<owner-list>
<owner id="processb6a988" mode="X"/>
</owner-list>
<waiter-list>
<waiter id="process6c492e8" mode="U" requestType="wait"/>
</waiter-list>
</ridlock>
<ridlock fileid="1" pageid="127478" dbid="5" objectname="MYDATABASE.dbo.MyNumber" id="lockfffffffff1974980" mode="X" associatedObjectId="72057594131120128">
<owner-list>
<owner id="process6c492e8" mode="X"/>
</owner-list>
<waiter-list>
<waiter id="processb6a988" mode="U" requestType="wait"/>
</waiter-list>
</ridlock>
</resource-list>
</deadlock>
</deadlock-list>
最佳答案
Shredding your deadlock graph成表格形式显示如下。
+----------+-------------------------+-----------+-----------+------------+----------+--------------------+--------------------+---------+
| LockMode | LockedObject | TranCount | LockEvent | LockedMode | WaitMode | WaitResource | IsolationLevel | LogUsed |
+----------+-------------------------+-----------+-----------+------------+----------+--------------------+--------------------+---------+
| U | MYDATABASE.dbo.MyNumber | NULL | rid | X | U | RID: 5:1:127478:20 | read committed (2) | 192 |
| U | MYDATABASE.dbo.MyNumber | NULL | rid | X | U | RID: 5:1:127478:16 | read committed (2) | 1848 |
+----------+-------------------------+-----------+-----------+------------+----------+--------------------+--------------------+---------+
序列生成代码是否每笔交易只调用一次,你们还没有回答我评论里的问题。
如果没有,很容易生成类似于您帖子中的死锁图。
设置
CREATE TABLE dbo.MyNumber
(
[TYPE] CHAR(1),
YRCLOSEDYN INT,
NEXTNO INT
)
INSERT INTO dbo.MyNumber
VALUES ('X', 0, 1),
('Y', 0, 1)
GO
CREATE PROC MyStoredProcedure @TYPE CHAR(1),
@NEXTNO INT OUTPUT
AS
UPDATE dbo.MyNumber
SET @NEXTNO = NEXTNO = NEXTNO + 1
WHERE ( [TYPE] = @TYPE )
AND ( YRCLOSEDYN = 0 )
连接1
BEGIN TRAN
DECLARE @NEXTNO INT
EXEC MyStoredProcedure 'Y', @NEXTNO OUTPUT
WAITFOR DELAY '00:00:05'
EXEC MyStoredProcedure 'X', @NEXTNO OUTPUT
ROLLBACK
连接2
(执行连接1中的代码后立即运行)
BEGIN TRAN
DECLARE @NEXTNO INT
EXEC MyStoredProcedure 'X', @NEXTNO OUTPUT
EXEC MyStoredProcedure 'Y', @NEXTNO OUTPUT
ROLLBACK
死锁图输出与上面的非常相似
+----------+-------------------------+-----------+-----------+------------+----------+-----------------+--------------------+---------+
| LockMode | LockedObject | TranCount | LockEvent | LockedMode | WaitMode | WaitResource | IsolationLevel | LogUsed |
+----------+-------------------------+-----------+-----------+------------+----------+-----------------+--------------------+---------+
| U | MYDATABASE.dbo.MyNumber | 2 | rid | X | U | RID: 11:1:144:1 | read committed (2) | 248 |
| U | MYDATABASE.dbo.MyNumber | 2 | rid | X | U | RID: 11:1:144:0 | read committed (2) | 248 |
+----------+-------------------------+-----------+-----------+------------+----------+-----------------+--------------------+---------+
如果这是对您的问题的解释,您需要确保在所有交易中以相同的顺序更新序列(我假设一定有一些很好的理由说明您不能只使用 an IDENTITY
column based solution )
关于sql-server-2008 - SQL Server 2008 : U and X locks - deadlock on one table without any indexes. 怎么办?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/13941886/