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Exception: ThrottlingBacklogTimeout. What is that exception about? RRS feed

  • Question

  • Hi guys,

    We keep having an exception recently: "ErrorCode:ThrottlingBacklogTimeout;The request has been throttled. Wait 10 seconds and try again. Operation type: C2DReceive; stackTrace:    at Microsoft.Azure.Devices.Client.Transport.HttpClientHelper.<ExecuteAsync>d__20.MoveNext()"

    It seems like a request to do something is throttled. Is that true?

    Does it cause by receiving message from cloud? Or is something we send to the cloud?

    Any ideas would be appreciated!

    Thanks,

    Ric

    Monday, June 5, 2017 12:29 AM

Answers

  • Hi @flyric717

    Could it be that you are hitting the throttling limitation for the Cloud to Device messages reception when using HTTP? See here for details on throttling.

    When using HTTP the reception of Cloud to Device messages is done with a pull from the device to the service (as HTTP is not bidirectional by nature), and the following limits apply for the various IoT Hub SKUs:

    • Free, S1 and S2: 16.67/sec/unit (1000/min/unit)
    • S3: 833.33/sec/unit (50000/min/unit)

    Tuesday, June 6, 2017 6:23 PM

All replies

  • Hi @flyric717

    Could it be that you are hitting the throttling limitation for the Cloud to Device messages reception when using HTTP? See here for details on throttling.

    When using HTTP the reception of Cloud to Device messages is done with a pull from the device to the service (as HTTP is not bidirectional by nature), and the following limits apply for the various IoT Hub SKUs:

    • Free, S1 and S2: 16.67/sec/unit (1000/min/unit)
    • S3: 833.33/sec/unit (50000/min/unit)

    Tuesday, June 6, 2017 6:23 PM
  • Hi Olivier, 

    Thanks for the reply!

    We have increased amount of our hub instances to see if that will solve our problem. 

    Will post updates here.

    Thanks,

    Ric

    Wednesday, June 7, 2017 4:35 AM
  • Just a quick update here: 

    It seems like that was the problem. We increased the number of S1 instances and the exception does not show up again so far. 

    Ric

    Monday, June 12, 2017 12:18 AM
  • Good to hear

    you mean you increased the number of units, right? not the number of instances of the service (meaning you still have a unique IoT Hub service instance with more units)?

    I just want to make sure people reading the answer here are clear on what they need to do if they hit the same limit

    Thanks

    Monday, June 12, 2017 3:50 PM
  • Hi Olivier,

    Yes. We increased the number of units. 

    Sorry for the confusion.

    Thanks,

    Ric

    Tuesday, June 13, 2017 5:23 AM