Dead locking when accessing the same table - sql

Question

I have a C# application that works with data in a SQL Server table via stored procedures.
If 2 users execute a form copy at the same time the same procedure is executed where dead locking occurs
I got xml_deadlock_report in SQL Server under system_health. Here is what it looks like:
<deadlock>
<victim-list>
<victimProcess id="process10f2ea0188" />
</victim-list>
<process-list>
<process id="process10f2ea0188" taskpriority="0" logused="7424" waitresource="PAGE: 5:1:24768207 " waittime="83419" ownerId="61921962" transactionname="user_transaction" lasttranstarted="2022-06-21T05:40:40.083" XDES="0x6d4f80d28" lockMode="S" schedulerid="5" kpid="2392" status="suspended" spid="69" sbid="0" ecid="0" priority="0" trancount="1" lastbatchstarted="2022-06-21T05:40:40.143" lastbatchcompleted="2022-06-21T05:40:40.083" lastattention="1900-01-01T00:00:00.083" clientapp=".Net SqlClient Data Provider" hostname="GKA" hostpid="12432" loginname="admin" isolationlevel="read committed (2)" xactid="61921962" currentdb="5" lockTimeout="4294967295" clientoption1="673185824" clientoption2="128048">
<executionStack>
<frame procname="CreateSectionTable" line="28" stmtstart="2856" stmtend="2984" sqlhandle="0x030005005611575922a96e01ccad000001000000000000000000000000000000000000000000000000000000">
SELECT #nTableIndex = Max(DataTableIndex) + 1 FROM SectionTable </frame>
<frame procname="CopySectionInt" line="118" stmtstart="9900" stmtend="10098" sqlhandle="0x030005001e33f860a2a96e01ccad000001000000000000000000000000000000000000000000000000000000">
EXEC CreateSectionTable #SectionId, '', '', ''
/* копирование в него структуры столбцов */ </frame>
<frame procname="CopyForm" line="73" stmtstart="6408" stmtend="6530" sqlhandle="0x03000500acea0f5f7ea96e01ccad000001000000000000000000000000000000000000000000000000000000">
EXEC CopySectionInt #SectionID, #FormId, null, null </frame>
</executionStack>
<inputbuf>
Proc [Database Id = 5 Object Id = 1594878636] </inputbuf>
</process>
<process id="process10ff03d498" taskpriority="0" logused="26216496" waitresource="PAGE: 5:1:23196243 " waittime="3894" ownerId="61920617" transactionname="user_transaction" lasttranstarted="2022-06-21T05:40:34.813" XDES="0x58a276d28" lockMode="S" schedulerid="6" kpid="4420" status="suspended" spid="66" sbid="0" ecid="0" priority="0" trancount="1" lastbatchstarted="2022-06-21T05:40:34.817" lastbatchcompleted="2022-06-21T05:40:34.813" lastattention="1900-01-01T00:00:00.813" clientapp=".Net SqlClient Data Provider" hostname="SQLSER" hostpid="6120" loginname="SS\Bo" isolationlevel="read committed (2)" xactid="61920617" currentdb="5" lockTimeout="4294967295" clientoption1="673185824" clientoption2="128048">
<executionStack>
<frame procname="CreateSectionTable" line="28" stmtstart="2856" stmtend="2984" sqlhandle="0x030005005611575922a96e01ccad000001000000000000000000000000000000000000000000000000000000">
SELECT #nTableIndex = Max(DataTableIndex) + 1 FROM SectionTable </frame>
<frame procname="CopySectionInt" line="118" stmtstart="9900" stmtend="10098" sqlhandle="0x030005001e33f860a2a96e01ccad000001000000000000000000000000000000000000000000000000000000">
EXEC CreateSectionTable #SectionId, '', '', ''
/* копирование в него структуры столбцов */ </frame>
<frame procname="CopyForm" line="73" stmtstart="6408" stmtend="6530" sqlhandle="0x03000500acea0f5f7ea96e01ccad000001000000000000000000000000000000000000000000000000000000">
EXEC CopySectionInt #SectionID, #FormId, null, null </frame>
</executionStack>
<inputbuf>
Proc [Database Id = 5 Object Id = 1594878636] </inputbuf>
</process>
</process-list>
<resource-list>
<pagelock fileid="1" pageid="24768207" dbid="5" subresource="FULL" objectname="SectionTable" id="locke19f0d280" mode="SIX" associatedObjectId="72057612168593408">
<owner-list>
<owner id="process10ff03d498" mode="SIX" />
</owner-list>
<waiter-list>
<waiter id="process10f2ea0188" mode="S" requestType="wait" />
</waiter-list>
</pagelock>
<pagelock fileid="1" pageid="23196243" dbid="5" subresource="FULL" objectname="SectionTable" id="locke4b2da480" mode="SIX" associatedObjectId="72057612168593408">
<owner-list>
<owner id="process10f2ea0188" mode="SIX" />
</owner-list>
<waiter-list>
<waiter id="process10ff03d498" mode="S" requestType="wait" />
</waiter-list>
</pagelock>
</resource-list>
</deadlock>
This is what the form copying procedure itself looks like (all the inputs, except the first parameter, are the same for the two processes.
For example, process1 = CopyForm (12345, 12, 35), process2 = CopyForm (54321, 12, 35)):
Here is the code itself with the procedures:
CREATE PROCEDURE [dbo].[CopyForm](#FormId as uniqueidentifier, #SrcFormId as uniqueidentifier, #DestFormTypeId as uniqueidentifier)
AS
BEGIN
/* Here we declare the variables */
SET NOCOUNT ON
SET ANSI_WARNINGS OFF
/*code to create a new form */
DECLARE cr CURSOR LOCAL FAST_FORWARD FOR
SELECT ObjectID FROM SectionTable
WHERE Form = #SrcFormId
ORDER BY OrderNum desc
OPEN cr
FETCH NEXT FROM cr INTO #SectionID
WHILE ##FETCH_STATUS = 0 BEGIN
EXEC CopySectionInt #SectionID, #FormId, null, null
FETCH NEXT FROM cr INTO #SectionID
END
CLOSE cr
DEALLOCATE cr
END
GO
CREATE PROCEDURE [dbo].[CopySectionInt](
#SrcSectionId as uniqueidentifier,
#DestFormId as uniqueidentifier,
#PrevSectId as uniqueidentifier,
#SectionId uniqueidentifier )
AS
BEGIN
/* Here we declare the variables */
SET NOCOUNT ON
IF #SectionId IS NULL SELECT #SectionId = newid()
IF #PrevSectId IS NULL
SET #nSectionNumber = 1
ELSE
SELECT #nSectionNumber = OrderNum + 1 FROM SectionTable WHERE ObjectID = #PrevSectId
/* Here we create a new section */
EXEC CreateSectionTable #SectionId
/* remaining code */
END
GO
CREATE PROCEDURE [dbo].[CreateSectionTable]( #argObjectID uniqueidentifier )
AS
BEGIN
/* Here we declare the variables */
SELECT #nSectionNumber = OrderNum FROM SectionTable WHERE ObjectID = #argObjectID
SELECT #nTableIndex = Max(DataTableIndex) + 1 FROM SectionTable
SET #nTableIndex = ISNULL( #nTableIndex, 1 )
UPDATE SectionTable SET DataTableIndex = #nTableIndex, OrderNum = #nSectionNumber WHERE ObjectID = #argObjectID
END
GO
I don't understand how these two processes are blocking each other if they are both accessing the same resource? And how can I fix this error?
Would blocking the CopyForm procedure with sp_getapplock help me in this case ? Or is there a way to solve the problem without blocking?