SQL Server 2005:读取提交事务隔离级别中的键范围锁定？

Question

我正在帮助解决使用SQL Server 2005的.NET应用程序中的一些死锁问题.我从下面的跟踪中获取了XML数据.

让我感到困惑的是,PK_Exp_Experience_PriorFirm当提交事务隔离级别时,RangeX-X锁定.

我读过的所有内容都表明您只获得了使用事务隔离级别"可序列化"的键范围锁定.到目前为止,我在我们的应用程序中找不到任何位置,我们将隔离级别设置为read committed之外的任何其他位置,下面的XML也表明我们正在使用read committed.

但是如果我们使用read-committed,我不明白跟踪如何显示有一个键范围锁定.有没有人有关于如何发生这种情况的想法？

<deadlock-list>
  <deadlock victim="processc2f438">
    <process-list>
      <process id="processc2f438" taskpriority="0" logused="13488" waitresource="KEY: 120:72057594583646208 (8201498b6efe)" waittime="484" ownerId="693258089" transactionname="user_transaction" lasttranstarted="2009-01-06T16:33:27.817" XDES="0xa71ce370" lockMode="U" schedulerid="1" kpid="9112" status="suspended" spid="53" sbid="0" ecid="0" priority="0" transcount="2" lastbatchstarted="2009-01-06T16:33:27.863" lastbatchcompleted="2009-01-06T16:33:27.863" clientapp=".Net SqlClient Data Provider" hostname="CHQAPT3" hostpid="6464" loginname="AppUser" isolationlevel="read committed (2)" xactid="693258089" currentdb="120" lockTimeout="4294967295" clientoption1="671088672" clientoption2="128056">
        <executionStack>
          <frame procname="adhoc" line="1" stmtstart="108" sqlhandle="0x0200000015d9962978fc6206b09e4c872150511b455e8923">
            UPDATE Exp_Experience_PriorFirm SET RelatedGuid = @newGuid WHERE RelatedGuid = @oldGuid
          </frame>
          <frame procname="mssqlsystemresource.sys.sp_executesql" line="1" sqlhandle="0x0400ff7fbe80662601000000000000000000000000000000">
            sp_executesql
          </frame>
          <frame procname="MyDb.dbo.Contact_MergeRelationships" line="74" stmtstart="4754" stmtend="4976" sqlhandle="0x0300780036a608461ed8af00669b00000100000000000000">
            EXEC sp_executesql @sql,
            N'@oldGuid uniqueidentifier, @newGuid uniqueidentifier',
            @oldGuid, @newGuid
          </frame>
          <frame procname="MyDb.dbo.Contact_Company_MergeRelationships" line="8" stmtstart="312" sqlhandle="0x03007800b271a129c8ccaf00669b00000100000000000000">
            EXEC Contact_MergeRelationships @oldGuid, @newGuid, 'Contact_Company', @excludedTableNames
          </frame>
        </executionStack>
        <inputbuf>
          Proc [Database Id = 120 Object Id = 698446258]
        </inputbuf>
      </process>
      <process id="processeb5d68" taskpriority="0" logused="14212" waitresource="KEY: 120:72057594594066432 (7c02a3a5890e)" waittime="2312" ownerId="693243114" transactionname="user_transaction" lasttranstarted="2009-01-06T16:33:20.957" XDES="0x8cdb9450" lockMode="S" schedulerid="2" kpid="9000" status="suspended" spid="73" sbid="0" ecid="0" priority="0" transcount="2" lastbatchstarted="2009-01-06T16:33:29.770" lastbatchcompleted="2009-01-06T16:33:29.770" clientapp=".Net SqlClient Data Provider" hostname="CHQAPT3" hostpid="6464" loginname="AppUser" isolationlevel="read committed (2)" xactid="693243114" currentdb="120" lockTimeout="4294967295" clientoption1="671088672" clientoption2="128056">
        <executionStack>
          <frame procname="MyDb.dbo.Contact_Company_Delete" line="27" stmtstart="1128" sqlhandle="0x03007800b0e5761877cbaf00669b00000100000000000000">
            DELETE FROM Contact WHERE GUID = @Guid;
          </frame>
        </executionStack>
        <inputbuf>
          Proc [Database Id = 120 Object Id = 410445232]
        </inputbuf>
      </process>
    </process-list>
    <resource-list>
      <keylock hobtid="72057594583646208" dbid="120" objectname="MyDb.dbo.Exp_Experience_PriorFirm" indexname="PK_Exp_Experience_PriorFirm" id="lockd1d43f80" mode="RangeX-X" associatedObjectId="72057594583646208">
        <owner-list>
          <owner id="processeb5d68" mode="RangeX-X"/>
        </owner-list>
        <waiter-list>
          <waiter id="processc2f438" mode="U" requestType="wait"/>
        </waiter-list>
      </keylock>
      <keylock hobtid="72057594594066432" dbid="120" objectname="MyDb.dbo.Contact_PersonCompanyLocation" indexname="PK_Contact_PersonCompanyLocation" id="lockd20c4380" mode="X" associatedObjectId="72057594594066432">
        <owner-list>
          <owner id="processc2f438" mode="X"/>
        </owner-list>
        <waiter-list>
          <waiter id="processeb5d68" mode="S" requestType="wait"/>
        </waiter-list>
      </keylock>
    </resource-list>
  </deadlock>
</deadlock-list>

Answer 1

PK_Exp_Experience_PriorFirm上的RangeX-X锁定被视为级联删除的一部分.

对于某些操作(如级联删除),SQL Server会自动将隔离级别升级为可序列化.

这里将对此进行更详细的描述:更新/删除级联RI上的Conor与隔离级别升级.