6 Replies Latest reply on Aug 22, 2018 7:39 AM by VasanthakumarR

    Analysis Service performance issue

    amitvankudre

      Hi All,

       

      I have around 2800 AF Analysis calcs running at 1 min freq. However, the Analysis service was not able to handle those and I tried using an offset, post which many of them started updating. I have currently divided into 6 groups, each with a frequency of 1 min and offsets of 3,6,9,etc...In spite of this, 5 of the 6 groups update correctly while 1 group always shows a lag, which increase with time.

       

      I believe that 2800 is not too big a number for Analysis service not to be able to handle those with 4 CPU cores and 16GB GB RAM.Is there a parameter I can change to resolve this evaluation lag ? Particularly, what is the EvaluationPartitionSize parameter and what does its default value of 10000 signify ? Can this be changed to ensure faster evaluation of all calcs ?

      Or is there any other method to resolve a calculation lag ?

       

      The current config is as below :

       

       

      Thanks and Regards,

      Amit Vankudre

        • Re: Analysis Service performance issue
          Roger Palmen

          Not a specific answer to your question, but why the CalculationWaitTimeInSeconds on 600? Default that is 5 seconds, and your setting introduces a delay of 10 minutes to every calculation by default...

          • Re: Analysis Service performance issue
            VasanthakumarR

            Hi Amit,

             

            There are many factors that may cause the performance issue with Analysis, like Issue with server performance because of memory and CPU cores in the Analysis machine,  Network issues etc.., I advise you to check the logs in PI Server and Analysis Server, Check the Analysis hang dump as per KB00046 - How to get a hang or crash dump and how to obtain and use debugging tools

             

            Let us know about the version of PI Analysis and the AF Client you are using.

             

            Check the Analysis Performance counters as per PI Server , this will give you the clear idea about the Analysis performance. For more details check the below link,

             

            Also, check the below KB articles for your reference,

            KB01641 - PI Analysis Service Best Practices

            KB01664 - How to Troubleshoot PI Analysis Service Performance

             

            -Vasanth.

            • Re: Analysis Service performance issue
              sraposo

              Hey Amit,

               

              Changing a configuration parameter may alleviate the performance issue, however a better approach is to understand why there is a performance issue in the first place. We have customers running hundreds of thousand analyses without any problems, so 2800 is definitely not a lot. The issue here is most likely that an analysis takes longer to evaluate than the frequency at which it is triggered. We typically only change configuration parameters if there is an absolute need.

               

              As a recommendation, is it possible for you to upgrade to AF 2018. In this version, PI System Explorer will give you an indication if the analysis won't be able to keep up:

               

               

              If the Avg Trigger is faster than the Avg time it takes to evaluate, then the analysis will always fall behind and perpetually lag. The solution for this is to either determine why the analysis is so expensive and fix it , or to decrease the frequency of the calculation. Expensive analyses are often explain by a violation in one or many of our best practices that can be found in this KB: KB01641 - PI Analysis Service Best Practices

               

              Is it possible for you to share the analysis configuration of one of the lagging analyses?

               

              Thanks,

              Seb

              3 of 3 people found this helpful
              • Re: Analysis Service performance issue
                VasanthakumarR

                Hi Amit,

                Can you please confirm your AF Client version as we have faced the similar kind of issue and OSIsoft advised us to upgrade the PI AF Client to  2018 version.

                We were running into internal WI 189018, and by extension, WI 195013 and OSIsoft confirmed that both of these issues were resolved in PI AF Client 2018, and upgrading the PI AF Client on the machine with the PI Analysis Service running is the only method available to resolve this issue. The one workaround that is available is to restart the PI Analysis Service.

                For your information,

                WI 189018-  This is an issue present in both PI AF Client 2017 and PI AF Client 2017 R2 that causes update consumer calls to dead lock when reconnecting to the PI Data Archive.

                WI 195013- This is an issue that would trigger when the update calls dead lock, would cause the problem to cascade to other threads and eventually cause the whole process to hang.

                Both are resolved in PI AF Client 2018 version.

                 

                -Vasanth.