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seanccc17-Peridot
17-Peridot
June 30, 2019
Question

How to prevent from deadlock in Thingworx ?

  • June 30, 2019
  • 6 replies
  • 2264 views

Hi, 

 

I wonder how the thingworx prevent from the deadlock ? 

Do I need to take care of the deadlock during developing the javascript service ? 

Does the Query* / Get* / Find* service of Thing generate SQL like select xxx for update ? 

 

Regards,

Sean

6 replies

Z
zyuan15-Regular Member
5-Regular Member
July 1, 2019

For your questions:

1. Deadlock does happen a lot in production environment if the Javascript is not carefully managed (long script, for loops, etc) . And if deadlock happens, the CPU will go high and Tomcat server down in a short time.  So to decrease that happening, carefully design the code, use some try catch block, leave some padding time between connected services and don't call the complex script too frequently.

 

2. the function are the same, and it searches data from the exact table in Persistence provider. Since Database like MSSQL and PGsql only accepts SQL command input, so yes, the API points to the Select commands

    C
    CarlesColl1-Visitor
    1-Visitor
    July 1, 2019

    Just my two cents:

    • Cut in pieces long lasting service calls, what's long? 10minutes of execution it's kind to going to kill your server
    • Build a queue system in order to control whats going on your system and also to control execution threads and load. Queue can allow you to cut in pieces long lasting services.
    • Write message logs (with total time execution) tor services that you expect that can last long
    • You never know what will be a long lasting service, why? you are dealing with remote connections (if you have edge connected devices with the SDK) and a remote service call can last a lot longer that what you expect.
    • Reading properties doesn't causes locks, but of course trying to read a persisted property can cause a locking on this thread if someone else is writing on it.
    • Lock on properties only are in place when writing on a persisted property, there isn't lock on memory only properties.
    • Scarcely use Async services (or never)
    • Again, build a queue system 😉 that should be a standard feature on ThingWorx

     

      S
      seanccc17-PeridotAuthor
      17-Peridot
      July 1, 2019

      @CarlesColl 

       

      Does the queue system you mean is the Event/Subscriber in Thingworx ? 

       

      Regards,

      Sean 

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