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I'm trying to stream data from my device to Azure IoT Hub to Stream Analytics to Power BI. Power BI implemented a new way to display streaming data. I would like to generate a line chart via the "Add tile" button on a Power BI Dashboard. This takes care of autorefresh of my streaming data chart.

My current streaming data (which works excellent when displayed statically in Power BI via "Create report"...) produces a rather weird line chart in streaming data mode: image.

My guess is that the arrival of new data in Power BI is not in chronological order. New data may be placed in the line chart in the correct temporal position but the line connecting the values is drawn in the order of arrival. This might cause the line to "jump back" in time?!

To minimize wrong ordering I am trying to prevent "adjusting other events" as well as accepting wrong ordering in Stream Analytics: configuration

The problem: with this configuration the Stream Analytics Job creates no output.

My ASA Query looks like this:

    SELECT 
      Name,
      Value,
      Timecreated,
    CAST (latest AS float) AS latest,
    COUNT(*)
    INTO
      [ToPowerBI]
    FROM
      [Eing-CANdata] TIMESTAMP BY Timecreated
    GROUP BY
      Name, Value,Timecreated,latest,
      tumblingWindow(Duration(Second, 1))

The "Timecreated" is formatted this way: 

     2017-03-06T11:51:22.246235Z

its accepted by Azure as timestamp.

Changing the configuration to accepting "out of order events with a timestamp in" the range of 10 seconds doesn't produce any output either.

The only way to create output is changing the configuration to "adjusting other events." But the Azure information tells me that "Adjust keeps the events and changes their timestamps". This would reorder the data which is not what I want.

My goals:

  1. get data through Stream Analytics as fast as possible
  2. avoid adjusting the timestamp as I need the original one!!
  3. ultimately get a proper (& "real-time-like") streaming data line chart in PowerBI

My question(s): Why is Stream Analytics not outputting any data in "Drop other events" mode? How can I get output from Stream Analytics in this mode?

(I have an important presentation coming up and your help would be greatly appreciated!)

Andy M.
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  • Since the change to the new Power BI streaming dataset, I noticed that the line graph "jerks" from time to time and this wasn't happening before. Have you tried setting the tumbling window value from 1 to 2 or 3 seconds? Another thing you can try is instead of using the timestamp sent by your device, you could try creating the value in the query like this: SELECT Name, Value, System.TimeStamp AS Timecreated. – CSharpRocks Mar 06 '17 at 12:13
  • @CSharpRocks Thank you for your suggestions! I tried setting the tumbling window value to 3 seconds (keeping the "drop other events" configuration) -> no output in Stream Analytics job. Then I additionally set SELECT ... System.TimeStamp AS Timecreated -> no output. Then I additionally changed the configuration to "Adjust other events" -> output is sent to PowerBI -> streaming data line chart is created. This time the line of the chart is no longer "jumping back" but instead "zigzagging" up and down wildly instead of creating a curve... – Andy M. Mar 06 '17 at 19:36

0 Answers0