Setting desired property in device twin sends the full content of the device twin instead of partial update

Question

Hello,

I am editing the device twin of my test device using the Azure IoT hub web portal. I added a single new desired property and I noticed that the full content of the device twin is received by my test device (including all the other properties I have not changed).

I would expect my device to receive a partial twin update containing only the modified property. Do I need to change settings on the web portal to send partial instead of full updates?

Thanks!

Answer 1

Hello @Guillaume,

welcome to this moderated Azure community forum.

The behavior you experience, receiving the full set of desired properties even when only one is changed, is the default behavior and cannot be modified.

The set of all desired properties must be seen as the complete desired state and must be handled as being 'atomic' (as in 'uncuttable').

The method used to handle desired property changes must be smart enough (or dump enough) to just process each separate desired property first. Only then, any action needed on any desired property change must be executed.

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