Question

我遇到一个奇怪的死锁问题，其中2个select count（1）查询死锁。死锁XML如下：

<deadlock>
   <victim-list>
      <victimProcess id="process966db2ca8" />
   </victim-list>
   <process-list>
      <process id="process966db2ca8" taskpriority="0" logused="444" waitresource="PAGE: 15:1:7396743 " waittime="1094" ownerId="3670863774" transactionname="implicit_transaction" lasttranstarted="2018-09-19T07:49:28.233" XDES="0x2cf8f8ad90" lockMode="S" schedulerid="13" kpid="15912" status="suspended" spid="822" sbid="0" ecid="0" priority="0" trancount="1" lastbatchstarted="2018-09-19T07:49:28.247" lastbatchcompleted="2018-09-19T07:49:28.243" lastattention="1900-01-01T00:00:00.243" clientapp="Microsoft JDBC Driver for SQL Server" hostname="PGPHXSMEE001" hostpid="0" loginname="smee_user" isolationlevel="read committed (2)" xactid="3670863774" currentdb="15" lockTimeout="4294967295" clientoption1="671088672" clientoption2="128058">
         <executionStack>
            <frame procname="adhoc" line="1" stmtstart="40" stmtend="246" sqlhandle="0x02000000e44c632f5ec6f6a3183f3379f5c550436b652bdd0000000000000000000000000000000000000000">unknown</frame>
            <frame procname="unknown" line="1" sqlhandle="0x0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000">unknown</frame>
         </executionStack>
         <inputbuf>(@P0 nvarchar(4000))select count(1) from SMEE_BookingManagement.dbo.booking_flagged_reason_mapping_t where gis_book_id = @P0</inputbuf>
      </process>
      <process id="process1fa2ebf468" taskpriority="0" logused="444" waitresource="PAGE: 15:1:1939674 " waittime="467" ownerId="3670873648" transactionname="implicit_transaction" lasttranstarted="2018-09-19T07:49:37.077" XDES="0xfca62c3b0" lockMode="S" schedulerid="6" kpid="11452" status="suspended" spid="808" sbid="0" ecid="0" priority="0" trancount="1" lastbatchstarted="2018-09-19T07:49:37.093" lastbatchcompleted="2018-09-19T07:49:37.090" lastattention="1900-01-01T00:00:00.090" clientapp="Microsoft JDBC Driver for SQL Server" hostname="PGPHXSMEE001" hostpid="0" loginname="smee_user" isolationlevel="read committed (2)" xactid="3670873648" currentdb="15" lockTimeout="4294967295" clientoption1="671088672" clientoption2="128058">
         <executionStack>
            <frame procname="adhoc" line="1" stmtstart="40" stmtend="246" sqlhandle="0x02000000e44c632f5ec6f6a3183f3379f5c550436b652bdd0000000000000000000000000000000000000000">unknown</frame>
            <frame procname="unknown" line="1" sqlhandle="0x0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000">unknown</frame>
         </executionStack>
         <inputbuf>(@P0 nvarchar(4000))select count(1) from SMEE_BookingManagement.dbo.booking_flagged_reason_mapping_t where gis_book_id = @P0</inputbuf>
      </process>
   </process-list>
   <resource-list>
      <pagelock fileid="1" pageid="7396743" dbid="15" subresource="FULL" objectname="SMEE_BookingManagement.dbo.BOOKING_FLAGGED_REASON_MAPPING_T" id="lock1c02483000" mode="IX" associatedObjectId="72057594057326592">
         <owner-list>
            <owner id="process1fa2ebf468" mode="IX" />
         </owner-list>
         <waiter-list>
            <waiter id="process966db2ca8" mode="S" requestType="wait" />
         </waiter-list>
      </pagelock>
      <pagelock fileid="1" pageid="1939674" dbid="15" subresource="FULL" objectname="SMEE_BookingManagement.dbo.BOOKING_FLAGGED_REASON_MAPPING_T" id="lock22f1a64f80" mode="SIX" associatedObjectId="72057594057326592">
         <owner-list>
            <owner id="process966db2ca8" mode="SIX" />
         </owner-list>
         <waiter-list>
            <waiter id="process1fa2ebf468" mode="S" requestType="wait" />
         </waiter-list>
      </pagelock>
   </resource-list>
</deadlock>

表结构如下：

GIS_BOOK_ID_I仅是gis_book_id上的非聚簇索引。

要注意的一件事是，我在多线程环境中运行此选择查询，在该环境中某些线程可能会在运行此计数查询之前通过SID从该表中删除某些记录。这是请求IX和SIX锁的原因吗？如果是这样，有什么办法可以解决或减少这种僵局的发生率？谢谢。

更新：我问客户，他说我们可以放心地添加（NOLOCK）提示，因为当线程正在运行时，该表不太可能被其他进程更新。但是，请随时建议是否有更好的方法来处理此僵局。谢谢。

SQL Server-2个选择之间的死锁

0 个答案: