I need some help to understand this deadlock scenario. We have concurrent deletes on a table. The operations deletes a record and insert a new one in a transaction (other tables are involved but no locks are reported on the deadlock graph). The concurrent operations are NOT targeting the same rows. The xml doesn't show a page lock neither. I don't understand why the deadlocks are happening. It happens either using Read Committed or Read Committed Snapshot isolation levels.
Here is the deadlock graph and xml:
xml_report
<deadlock>
<victim-list>
<victimProcess id="process111c0a04e8"/>
</victim-list>
<process-list>
<process id="process111c0a04e8" taskpriority="0" logused="988" waitresource="KEY: 5:72057594052476928 (cdccc9664fb5)" waittime="572" ownerId="402767" transactionname="implicit_transaction" lasttranstarted="2023-08-09T15:56:06.700" XDES="0x113940c428" lockMode="S" schedulerid="6" kpid="32656" status="suspended" spid="67" sbid="0" ecid="0" priority="0" trancount="2" lastbatchstarted="2023-08-09T15:56:06.753" lastbatchcompleted="2023-08-09T15:56:06.743" lastattention="1900-01-01T00:00:00.743" clientapp="Microsoft JDBC Driver for SQL Server" hostname="W3737985" hostpid="0" loginname="sa" isolationlevel="snapshot (5)" xactid="402767" currentdb="5" currentdbname="bcecm" lockTimeout="4294967295" clientoption1="671088672" clientoption2="128058">
<executionStack>
<frame procname="adhoc" line="1" stmtstart="40" stmtend="112" sqlhandle="0x02000000f1caf30cb9946dc3186f8369fd94f3a26b002a540000000000000000000000000000000000000000"> unknown </frame>
<frame procname="unknown" line="1" sqlhandle="0x0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"> unknown </frame>
</executionStack>
<inputbuf> (@P0 nvarchar(4000))delete from Documento WHERE id = @P0 </inputbuf>
</process>
<process id="processb8de6eca8" taskpriority="0" logused="988" waitresource="KEY: 5:72057594052476928 (cdccc9664fb5)" waittime="572" ownerId="402796" transactionname="implicit_transaction" lasttranstarted="2023-08-09T15:56:06.767" XDES="0x113430c428" lockMode="S" schedulerid="9" kpid="36848" status="suspended" spid="68" sbid="0" ecid="0" priority="0" trancount="2" lastbatchstarted="2023-08-09T15:56:06.823" lastbatchcompleted="2023-08-09T15:56:06.813" lastattention="1900-01-01T00:00:00.813" clientapp="Microsoft JDBC Driver for SQL Server" hostname="W3737985" hostpid="0" loginname="sa" isolationlevel="snapshot (5)" xactid="402796" currentdb="5" currentdbname="bcecm" lockTimeout="4294967295" clientoption1="671088672" clientoption2="128058">
<executionStack>
<frame procname="adhoc" line="1" stmtstart="40" stmtend="112" sqlhandle="0x02000000f1caf30cb9946dc3186f8369fd94f3a26b002a540000000000000000000000000000000000000000"> unknown </frame>
<frame procname="unknown" line="1" sqlhandle="0x0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"> unknown </frame>
</executionStack>
<inputbuf> (@P0 nvarchar(4000))delete from Documento WHERE id = @P0 </inputbuf>
</process>
<process id="process1117804108" taskpriority="0" logused="988" waitresource="KEY: 5:72057594052476928 (1af84d4c4a2b)" waittime="99" ownerId="402813" transactionname="implicit_transaction" lasttranstarted="2023-08-09T15:56:06.780" XDES="0x1142190428" lockMode="S" schedulerid="1" kpid="34780" status="suspended" spid="72" sbid="0" ecid="0" priority="0" trancount="2" lastbatchstarted="2023-08-09T15:56:06.830" lastbatchcompleted="2023-08-09T15:56:06.823" lastattention="1900-01-01T00:00:00.823" clientapp="Microsoft JDBC Driver for SQL Server" hostname="W3737985" hostpid="0" loginname="sa" isolationlevel="snapshot (5)" xactid="402813" currentdb="5" currentdbname="bcecm" lockTimeout="4294967295" clientoption1="671088672" clientoption2="128058">
<executionStack>
<frame procname="adhoc" line="1" stmtstart="40" stmtend="112" sqlhandle="0x02000000f1caf30cb9946dc3186f8369fd94f3a26b002a540000000000000000000000000000000000000000"> unknown </frame>
<frame procname="unknown" line="1" sqlhandle="0x0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000"> unknown </frame>
</executionStack>
<inputbuf> (@P0 nvarchar(4000))delete from Documento WHERE id = @P0 </inputbuf>
</process>
</process-list>
<resource-list>
<keylock hobtid="72057594052476928" dbid="5" objectname="bcecm.dbo.documento" indexname="PK__document__3213E83FFA04E697" id="lock113213f500" mode="X" associatedObjectId="72057594052476928">
<owner-list>
<owner id="processb8de6eca8" mode="S" requestType="wait"/>
</owner-list>
<waiter-list>
<waiter id="process111c0a04e8" mode="S" requestType="wait"/>
</waiter-list>
</keylock>
<keylock hobtid="72057594052476928" dbid="5" objectname="bcecm.dbo.documento" indexname="PK__document__3213E83FFA04E697" id="lock113213f500" mode="X" associatedObjectId="72057594052476928">
<owner-list>
<owner id="process1117804108" mode="X"/>
</owner-list>
<waiter-list>
<waiter id="processb8de6eca8" mode="S" requestType="wait"/>
</waiter-list>
</keylock>
<keylock hobtid="72057594052476928" dbid="5" objectname="bcecm.dbo.documento" indexname="PK__document__3213E83FFA04E697" id="lock112348fb80" mode="X" associatedObjectId="72057594052476928">
<owner-list>
<owner id="process111c0a04e8" mode="X"/>
</owner-list>
<waiter-list>
<waiter id="process1117804108" mode="S" requestType="wait"/>
</waiter-list>
</keylock>
</resource-list>
</deadlock>
After a careful look on the execution plan of the deletes I found what might be causing the issue. The table had a foreing key targeting another column on the same table (it is a hierarchical entity). The deadlock graph shows that the deadlock occurs on the primary key but in fact it was caused because of this FK. Removing the FK and controlling referencial integrity on the application solved the problem.