MSSQL Server DEADLOCK

[LP_10027711]

Hello, I keep getting once or twice a week this DEADLOCK error in our system. we have looked are timers, schedulers, nested loops, with no final solution. I need urgent help to figure out what is causing it.

Attached is Application Screenshot and Log Files.

[VladimirN · Accepted solution]

 Hi,

1.  Articles:

• ""APPARENT DEADLOCK!!!" is seen in the ApplicationLog.log and ThingWorx Platform becoems unresponsive after starting a connected Azure IoT Hub": https://www.ptc.com/en/support/article/CS360787 
• "Unable to log in ThingWorx with error "APPARENT DEADLOCK" in ThingWorx": https://www.ptc.com/en/support/article/CS331538 
• "The H2 database does not back up properly in ThingWorx and deadlock errors are noticed in logsv": https://www.ptc.com/en/support/article/cs299595 
• "Detecting Deadlocks / Blocked Statements in PostgreSQL for ThingWorx Platform": https://www.ptc.com/en/support/article/cs255556 

2. There have been similar questions before:

• "Thingworx Application is down frequently?": https://community.ptc.com/t5/ThingWorx-Developers/Thingworx-Application-is-down-frequently/td-p/616980 
• "APPARENT DEADLOCK Issue": https://community.ptc.com/t5/ThingWorx-Developers/APPARENT-DEADLOCK-Issue/td-p/561136 

3. From "Help Center":

• "Fixed an issue that was causing SQL Server apparent deadlock exceptions": http://support.ptc.com/help//thingworx_hc/thingworx_8_hc/en/index.html#page/ThingWorx/Help/Release_Notes/Version8.2.0ReleaseNotes.html 
• "Using ThingWorx Logs to Monitor Database Performance": https://support.ptc.com/help/thingworx_hc/thingworx_8_hc/en/index.html#page/ThingWorx/Help/Best_Practices_for_Developing_Applications/monitoring_operating_system_database_performance_TWX_log.html