3 Replies Latest reply on Apr 11, 2018 6:50 AM by JanWortmann

    Which AF DR to use for best performance

    JanWortmann

      We are running the data archiv and the asset framework on different servers.

      So to minimize the data traffic between both machines we decided to have an AF-ELEMENT with a PIPoint-DR-Attribute for each Tag in our archiv. Within the AF we want to reference allways these Attributes (with direct PiPoint DR) instead of the PiPoints in the archive. Now we have to choose which DR type we want to use (String Buider, Formula, indirect PiPoint?).

       

      For the later use of these Attributes with references to other attributes e.g. in EventFrames I would prefer to use indirect PiPoint DR. But how would this inpact the performance of our system? Does anyone have experience with that or is our whole idea misleading?

       

      Thanks

      Jan

       

      System Information:

      Explorer and AF Server Version 2.9.1.8106

        • Re: Which AF DR to use for best performance
          Rick Davin

          Hi Jan,

           

          For anything attributes reading PI data, you should use the PIPoint DR.  StringBuilder DR will still have to call PIPoint DR, fetch the values, convert them to string, and then on the event frame the attribute converts it back to numeric.  If you call PIPoint DR directly, you avoid the intermediary of StringBuilder DR, and you have the visual icon of a PI tag that lets you know where the data really is coming from.  Plus you have additional features of PIPoint DR, such as TimeRangeMethod, that are very valuable on an event frame where maybe you want the PIPoint value at StartTime, whereas StringBuilder can only produce it at EndTime.

          2 of 2 people found this helpful
          • Re: Which AF DR to use for best performance
            sraposo

            Hi Jan,

             

            In addition to Rick's answer, as a general rule, PI Point DR have the best performance as the data is stored in the PI Data Archive. The other data references: String Builder, Formula, Analysis DR and referring indirectly to another attribute with a PI Point DR require additional computation client side.

             

            Hope this helps,

            Seb

            • Re: Which AF DR to use for best performance
              JanWortmann

              Hi Rick,

               

              Many thanks for your answer.

              This was also my impression.

              I will discuss it with my PI administrator.

               

              Jan