我有一个 Java 应用程序,它在数据库上执行多个并发 CRUD 操作。我正在添加对 SQLServer 的支持,但在并发删除期间遇到死锁问题。经过一些调查,问题似乎是由于特定表上的锁升级。
为了修复它,我决定使用 UPDLOCK 提示对有问题的表进行所有读取以“更新”,这样就可以避免死锁。但是,我仍然看到了问题。我在 SQLServer 中启用了跟踪,并在 SQLServer 日志中发现了以下死锁跟踪:
遇到死锁....打印死锁信息等待图
节点:1 密钥:5:72057594042384384(54048e7b3828)CleanCnt:3 模式:X 标志:0x0 授权列表 1:所有者:0x03D08C40 模式:X Flg:0x0 参考:0 寿命:02000000 SPID:62 ECID:0 XactLockInfo:0x04834274 SPID: 62 ECID:0 语句类型:DELETE 行号:1 输入缓冲区:语言事件:(@P0 nvarchar(4000))delete from part_data where part_id = @P0 请求者:ResType:LockOwner Stype:'OR'Xdes:0x04B511C8 模式: U SPID:60 BatchID:0 ECID:0 TaskProxy:(0x058BE378) Value:0x3d08500 Cost:(0/1296)
节点:2
KEY: 5:72057594042384384 (f903d6d6e0ac) CleanCnt:2 Mode:X Flags: 0x0 Grant List 0: Owner:0x03D088A0 Mode: X Flg:0x0 Ref:0 Life:02000000 SPID:60 ECID:0 XactLockInfo:0x04B511EC SPID:60 ECID: 0 语句类型:DELETE 行号:1 输入缓冲区:语言事件:(@P0 nvarchar(4000))delete from part_data where part_id = @P0 请求者:ResType:LockOwner Stype:'OR'Xdes:0x04834250 模式:U SPID: 62 BatchID:0 ECID:0 TaskProxy:(0x047BA378) 值:0x3d089e0 成本:(0/4588)
受害者资源所有者:ResType:LockOwner Stype:'OR'Xdes:0x04B511C8 模式:U SPID:60 BatchID:0 ECID:0 TaskProxy:(0x058BE378)值:0x3d08500 成本:(0/1296)
SQLServer 探查器将此显示为两个客户端持有更新 (U) 锁并试图升级为独占 (X) 锁。我读过的 SQLServer 文档说,在给定时间,只有一个客户端可以在表上拥有 (U) 锁,所以我想知道为什么我会看到跟踪中显示的情况。
该跟踪中引用的数据库对象是外键上的索引。如果有解决此类问题经验的人可以提供建议,那将是一个很大的帮助。
谢谢,布拉德。
编辑按要求添加了死锁图xml:
<deadlock-list>
<deadlock victim="process989018">
<process-list>
<process id="process6aa7a8" taskpriority="0" logused="4844" waitresource="KEY: 5:72057594042384384 (5504bdfb7529)" waittime="9859" ownerId="613553" transactionname="implicit_transaction" lasttranstarted="2009-05-08T11:52:39.137" XDES="0x5fcbc30" lockMode="U" schedulerid="1" kpid="3516" status="suspended" spid="59" sbid="0" ecid="0" priority="0" transcount="2" lastbatchstarted="2009-05-08T11:52:39.183" lastbatchcompleted="2009-05-08T11:52:39.183" clientapp="jTDS" hostname="LOIRE" hostpid="123" loginname="sa" isolationlevel="read committed (2)" xactid="613553" currentdb="5" lockTimeout="4294967295" clientoption1="671088672" clientoption2="128058">
<executionStack>
<frame procname="adhoc" line="1" stmtstart="40" sqlhandle="0x0200000007c76c39efdd8317c6fa7b611b4fd958f05cfcf4">
delete from part_data where part_id = @P0 </frame>
</executionStack>
<inputbuf>(@P0 nvarchar(4000))delete from part_data where part_id = @P0</inputbuf>
</process>
<process id="process989018" taskpriority="0" logused="1528" waitresource="KEY: 5:72057594042384384 (5e0405cb0377)" waittime="1250" ownerId="613558" transactionname="implicit_transaction" lasttranstarted="2009-05-08T11:52:39.183" XDES="0x48318f0" lockMode="U" schedulerid="2" kpid="2692" status="suspended" spid="60" sbid="0" ecid="0" priority="0" transcount="2" lastbatchstarted="2009-05-08T11:52:39.183" lastbatchcompleted="2009-05-08T11:52:39.183" clientapp="jTDS" hostname="LOIRE" hostpid="123" loginname="sa" isolationlevel="read committed (2)" xactid="613558" currentdb="5" lockTimeout="4294967295" clientoption1="671088672" clientoption2="128058">
<executionStack>
<frame procname="adhoc" line="1" stmtstart="40" sqlhandle="0x0200000007c76c39efdd8317c6fa7b611b4fd958f05cfcf4">
delete from part_data where part_id = @P0 </frame>
</executionStack>
<inputbuf>(@P0 nvarchar(4000))delete from part_data where part_id = @P0</inputbuf>
</process>
</process-list>
<resource-list>
<keylock hobtid="72057594042384384" dbid="5" objectname="MESSAGESTOREDB61.dbo.part_data" indexname="idx_part_data_part_id" id="lock3cab740" mode="X" associatedObjectId="72057594042384384">
<owner-list>
<owner id="process6aa7a8" mode="X"/>
</owner-list>
<waiter-list>
<waiter id="process989018" mode="U" requestType="wait"/>
</waiter-list>
</keylock>
<keylock hobtid="72057594042384384" dbid="5" objectname="MESSAGESTOREDB61.dbo.part_data" indexname="idx_part_data_part_id" id="lock3cad340" mode="X" associatedObjectId="72057594042384384">
<owner-list>
<owner id="process989018" mode="X"/>
</owner-list>
<waiter-list>
<waiter id="process6aa7a8" mode="U" requestType="wait"/>
</waiter-list>
</keylock>
</resource-list>
</deadlock>
</deadlock-list>