DEADLOCK - ON INSERT but Graph shows on UPDATE

Question

HI Experts, Please can you look at below graph , queries invloved in deadlock are insert queries but deadlock graph shows it's waiting for IU lock , please suggest why this is happening and possible solution on this ?<deadlock>
<victim-list>
<victimProcess id="processfe4f4c8" />
</victim-list>
<process-list>
<process id="processfe4f4c8" taskpriority="0" logused="0" waitresource="PAGE: 16:15:2763616" waittime="18910" ownerId="14792928887" transactionname="INSERT" lasttranstarted="2014-12-01T03:18:56.583" XDES="0x98461ce90" lockMode="U" schedulerid="8" kpid="322972" status="suspended" spid="157" sbid="0" ecid="0" priority="0" trancount="2" lastbatchstarted="2014-12-01T03:18:56.527" lastbatchcompleted="2014-12-01T03:18:56.523" clientapp="Microsoft SQL Server" hostname="LDNPSM020012787" hostpid="11512" loginname="INTRANET\sysStrAggProdRW" isolationlevel="read committed (2)" xactid="14792928887" currentdb="16" lockTimeout="4294967295" clientoption1="671221856" clientoption2="128056">
<executionStack>
<frame procname="" line="9" stmtstart="614" sqlhandle="0x03001000714adf585beadc00f1a300000000000000000000" />
<frame procname="" line="4" stmtstart="132" sqlhandle="0x02000000dcb4f83081b8eccb8453ddd8d8b68d18e5e102f7" />
<frame procname="" line="1" sqlhandle="0x000000000000000000000000000000000000000000000000" />
</executionStack>
<inputbuf>
(@P1 datetime2(0))declare @cobdate datetime;
set @cobDate = @P1;
INSERT INTO [risk].[VolckerSignoffDetailed]
( [CobDate]
,[ChorusId]
,[RiskManager]
,[Description]
,[Currency]
,[Tenor]
,[Sensitivity]
,[RiskMetricValue]
,[AssetClass]
,[FunctionalGroup]
,[Desk]
,[NoRiskFlag])
SELECT
[CobDate]
,vfs.[ChorusId]
,coalesce(vmn.RiskManager,'Unknown')
,[SensitivityDescription]
,[Ccy]
,[Tenor]
,[SensitivityType]
,[SensitivityValue]
,'Fx'
,coalesce(vmn.FunctionalGroup,'Unknown')
,coalesce(vmn.Desk,'Unknown')
,0
FROM [Rover].[risk].[VolckerFxSensitivityReport_history] vfs
LEFT JOIN risk.VolckerMarsNodeSignOffData vmn ON vfs.ChorusId = vmn.ChorusId
WHERE cobDate = @cobDate
UNION ALL
SELECT @cobDate
,mm.ChorusId
,coalesce(vmnsd.RiskManager,'Unknown')
,NULL
,NULL
,vmn.Sensitivity
,0
,'Fx'
,coalesce(vmnsd.Function </inputbuf>
</process>
<process id="processfe4fdc8" taskpriority="0" logused="16200" waitresource="PAGE: 16:15:2681345" waittime="3546" ownerId="14792751373" transactionname="INSERT" lasttranstarted="2014-12-01T03:17:57.960" XDES="0x438882e90" lockMode="X" schedulerid="8" kpid="323636" status="suspended" spid="74" sbid="0" ecid="0" priority="0" trancount="2" lastbatchstarted="2014-12-01T03:17:56.683" lastbatchcompleted="2014-12-01T03:17:56.580" clientapp="Microsoft SQL Server" hostname="LDNPSM020012787" hostpid="13984" loginname="INTRANET\sysStrAggProdRW" isolationlevel="read committed (2)" xactid="14792751373" currentdb="16" lockTimeout="4294967295" clientoption1="671221856" clientoption2="128056">
<executionStack>
<frame procname="" line="9" stmtstart="614" sqlhandle="0x03001000714adf585beadc00f1a300000000000000000000" />
<frame procname="" line="4" stmtstart="132" sqlhandle="0x0200000094fe01033c05ace97f13efdd7dca36b6e6c8c03d" />
<frame procname="" line="1" sqlhandle="0x000000000000000000000000000000000000000000000000" />
</executionStack>
<inputbuf>
(@P1 datetime2(0))declare @cobdate datetime;
set @cobDate = @P1;
INSERT INTO [risk].[VolckerSignoffDetailed]
( [CobDate]
,[ChorusId]
,[RiskManager]
,[Currency]
,[Product]
,[Sensitivity]
,[RiskMetricValue]
,[AssetClass]
,[FunctionalGroup]
,[Desk]
,[NoRiskFlag])
SELECT
[CobDate]
,vss.[ChorusId]
,coalesce(vmn.RiskManager,'Unknown')
,[Currency]
,[Product]
,[Sensitivity]
,[RiskMetricValue]
,'SecProducts'
,coalesce(vmn.FunctionalGroup,'Unknown')
,coalesce(vmn.Desk,'Unknown')
,0
FROM [Rover].[risk].[VolckerSecProductsSensitivityReport_history] vss
LEFT JOIN risk.VolckerMarsNodeSignOffData vmn ON vss.ChorusId = vmn.ChorusId
WHERE cobDate = @cobDate
UNION ALL
SELECT @cobDate
,mm.ChorusId
,coalesce(vmnsd.RiskManager,'Unknown')
,NULL
,vmn.Sensitivity
,0
,'SecProducts'
,coalesce(vmnsd.FunctionalGroup,'Unknown')
,c </inputbuf>
</process>
</process-list>
<resource-list>
<pagelock fileid="15" pageid="2763616" dbid="16" objectname="" id="lock6ca651a80" mode="U" associatedObjectId="72057594417643520">
<owner-list>
<owner id="processfe4fdc8" mode="U" />
</owner-list>
<waiter-list>
<waiter id="processfe4f4c8" mode="U" requestType="wait" />
</waiter-list>
</pagelock>
<pagelock fileid="15" pageid="2681345" dbid="16" objectname="" id="lock3c5a70480" mode="IU" associatedObjectId="72057594417774592">
<owner-list>
<owner id="processfe4f4c8" mode="IU" />
</owner-list>
<waiter-list>
<waiter id="processfe4fdc8" mode="X" requestType="convert" />
</waiter-list>
</pagelock>
</resource-list>
</deadlock>
Shivraj Patil.

Answer 1

It's difficult to tell exactly what is going on without further information about the database. We would also need to map the pages to tables, which you can do with DBCC PAGE. (Which is undocumented, though.)
The U(pdate) lock here has nothing to do with an UPDATE statement. An Update lock on a resource, is a read lock, but which indicates that the process wil later perform an update on the resource. There can only be one U lock on a resource. The resource in this
question is a page, and an INSERT will cause an update to a page somewhere.
The other locks are IU (Intent-Update) which indicates that the process holds U locks on a resource on lower level, that is a row in this case. X is an exclusive lock.
Erland Sommarskog, SQL Server MVP, [email protected]