同一等待资源上的死锁

Question

我在 SQL Server 中遇到死锁，但我不明白为什么会出现死锁。看起来这两个资源实际上是一样的。这意味着他们每个人都拥有锁并再次请求相同的锁，这被 SQL 标记为死锁。

桌子：

CREATE TABLE [dbo].[Device](
[Id] [bigint] IDENTITY(1,1) NOT NULL,
[DeviceType] [nvarchar](255) NOT NULL,
[ControllerIdentifier] [nvarchar](255) NULL,
[Created] [datetimeoffset](7) NULL,
[LastModified] [datetimeoffset](7) NULL,
[DeviceId] [nvarchar](255) NULL,
[TypeDescription] [nvarchar](255) NULL,
[IpAddress] [nvarchar](255) NULL,
[Number] [bigint] NULL,
[SerialNumber] [bigint] NULL,
[SoftwareVersionApplication] [nvarchar](255) NULL,
[Type] [nvarchar](255) NULL,
[State] [nvarchar](255) NULL,
[StateUpdated] [datetimeoffset](7) NULL,
[MainType] [nvarchar](255) NULL,
[SubType] [nvarchar](255) NULL,
[Firmware] [nvarchar](255) NULL,
[ConfigurationUpdated] [datetimeoffset](7) NULL,
[ConsumptionType] [nvarchar](255) NULL,
[VendorId] [nvarchar](255) NULL,
[Owner] [nvarchar](255) NULL,
[SupportsAutoCollection] [bit] NULL,
[RepeaterStatus] [int] NULL,
[SoftwareVersion] [int] NULL,
[EnergyConsumption] [int] NULL,
[NetworkId] [int] NULL,
[AmbientTemperature] [int] NULL,
[InstallationText] [nvarchar](255) NULL,
[RepeaterListCapacity] [int] NULL,
[RepeaterListRevision] [int] NULL,
PRIMARY KEY CLUSTERED 
(
[Id] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, 
  IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, 
  ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY]

死锁（注意，更新不会更新同一行）：

<deadlock-list>
  <deadlock victim="process403ddc8">
    <process-list>
      <process id="process403ddc8" taskpriority="0" logused="4744" waitresource="KEY: 7:72057594038845440 (7f25ce0760b0)" waittime="1944" ownerId="66977" transactionname="user_transaction" lasttranstarted="2013-03-19T15:42:22.500" XDES="0x81603950" lockMode="X" schedulerid="4" kpid="2668" status="suspended" spid="54" sbid="2" ecid="0" priority="0" trancount="2" lastbatchstarted="2013-03-19T15:42:23.100" lastbatchcompleted="2013-03-19T15:42:23.100" clientapp=".Net SqlClient Data Provider"  hostpid="2880" isolationlevel="read committed (2)" xactid="66977" currentdb="7" lockTimeout="4294967295" clientoption1="671088672" clientoption2="128056">
        <executionStack>
         <frame procname="adhoc" line="1" stmtstart="68" sqlhandle="0x0200000028bdf306b502658c1a2f98fca4a8a97bff26be80">
UPDATE [Device] SET LastModified = @p0 WHERE Id = @p1     </frame>
        <frame procname="unknown" line="1" sqlhandle="0x000000000000000000000000000000000000000000000000">
unknown     </frame>
    </executionStack>
   <inputbuf>
(@p0 datetimeoffset(7),@p1 bigint)UPDATE [Device] SET LastModified = @p0 WHERE Id = @p1    </inputbuf>
 </process>
 <process id="process3daf948" taskpriority="0" logused="7268" waitresource="KEY: 7:72057594038845440 (94675634c2ef)" waittime="1933" ownerId="66980" transactionname="user_transaction" lasttranstarted="2013-03-19T15:42:22.507" XDES="0x84138e80" lockMode="X" schedulerid="1" kpid="2848" status="suspended" spid="56" sbid="2" ecid="0" priority="0" trancount="2" lastbatchstarted="2013-03-19T15:42:23.110" lastbatchcompleted="2013-03-19T15:42:23.110" clientapp=".Net SqlClient Data Provider"  hostpid="2880" isolationlevel="read committed (2)" xactid="66980" currentdb="7" lockTimeout="4294967295" clientoption1="671088672" clientoption2="128056">
 <executionStack>
  <frame procname="adhoc" line="1" stmtstart="68" sqlhandle="0x0200000028bdf306b502658c1a2f98fca4a8a97bff26be80">
 UPDATE [Device] SET LastModified = @p0 WHERE Id = @p1     </frame>
 <frame procname="unknown" line="1" sqlhandle="0x000000000000000000000000000000000000000000000000">
unknown     </frame>
</executionStack>
<inputbuf>
(@p0 datetimeoffset(7),@p1 bigint)UPDATE [Device] SET LastModified = @p0 WHERE Id =   @p1    </inputbuf>
</process>
</process-list>
<resource-list>
<keylock hobtid="72057594038845440" dbid="7" objectname="UtiliDriver.dbo.Device" indexname="PK__Device__3214EC0703317E3D" id="lock823f4a00" mode="X" associatedObjectId="72057594038845440">
<owner-list>
 <owner id="process3daf948" mode="X"/>
</owner-list>
<waiter-list>
 <waiter id="process403ddc8" mode="X" requestType="wait"/>
</waiter-list>
</keylock>
<keylock hobtid="72057594038845440" dbid="7" objectname="UtiliDriver.dbo.Device" indexname="PK__Device__3214EC0703317E3D" id="lock8015d980" mode="X" associatedObjectId="72057594038845440">
 <owner-list>
 <owner id="process403ddc8" mode="X"/>
 </owner-list>
 <waiter-list>
  <waiter id="process3daf948" mode="X" requestType="wait"/>
  </waiter-list>
  </keylock>
 </resource-list>
 </deadlock>
</deadlock-list>

Answer 1

下面的代码将为您提供死锁中涉及的两行，该行摘自The Curious Case of the Dubious Deadlock and the Not So Logical Lock

SELECT *, %%lockres%%
FROM UtiliDriver.dbo.Device WITH (NOLOCK)
WHERE %%lockres%% IN('(7f25ce0760b0)','(94675634c2ef)')

来自@RemusRusanu 在Lockres 碰撞概率标记中%%lockres%% 的良好背景。