GUIDANCE::Query causing "Dynamic datasources not supported" error

[Element115]

For those of you familiar with Unix man pages, you can have something similar inside your Power Query Editor desktop version.  It allows you to have a reference to all the functions right from inside the editor and looks like this:

You can see at bottom a few function names. Click on one, and you get a description of what it does and the parameter list, if any, to use it properly:

The M code to get this is:

let
    Source = #shared
in
    Source

This works in the desktop version of the Power Query editor.  If you try in the Fabric version, that is, with a Dataflow Gen2, the DF will not publish and fail with the error:  Dynamic datasources are not supported.  I have notified support and they said they will pass it along to the Product Team.  Nonetheless, I will post it as an idea in the Idea Forums.  Not a crucial thing to have, for sure, but it's a nice and useful convenience to be able to look up functions from within the editor itself.

[miguel · Accepted solution]

You can have a query that uses #shared or #sections in a Dataflow Gen2, but since these are dynamic queries in order for them to not cause any issues you need to make sure that they're not set to be loaded anywhere not are they set to be staged.

What's missing today in the Power Query Online experience is the ability to see the full description and documentation of the function. We're internally tracking this gap between the legacy Power Query Desktop UI experience and the new one found in Power Query Online.

Be sure to post the idea in aka.ms/FabricIdeas to help us prioritize this gap, but the behavior that you're seeing today on how the dataflow behaves with a dynamic query like that is by design. If you have any porposals to change this by-design behavior, please be sure to suggest it in the Ideas Portal as well.

Best!

[Element115]

By the way, are you by any chance the co-author of 'Master your data with Power Query'? 

[miguel]

I am. Yes.

[Element115]

Awesome!  Great book btw, which I recommend to everyone. Now we need a book that teaches how to program in M, especially all the esoteric tricks of functional programming applied to table processing because the Microsoft documentation is unfortunately not even the bare minimum.

[Element115]

@miguel I did post the idea in aka.ms/FabricIdeas but what do you mean by the 'Ideas Portal'?  I am not familiar with this. Another site?

[miguel]

Same site. Fabric Ideas forum is just another name for the Fabric Ideas portal.

[v-gchenna-msft]

Hi @Element115 ,

Thanks for using Fabric Community. 
As I understand you have already notified support about this idea. 

Appreciate if you could share the idea in our Idea Forum . Idea in this forum would be open for the user community to upvote & comment on. This allows our product teams to effectively prioritize your request against our existing feature backlog and gives insight into the potential impact of implementing the suggested feature.

Hope this helps. Please let me know if you have any further queries.

[Element115]

I did but what a mess that site is. If I post the code snippet or copy/paste the permalink of this post, the Ideas editor generates an error message that there is some malicious content and blocks the posting.

I finally figured out that instead of grabbing the permalink and pasting it, if you just paste the full URL as text, then no error is generated. Why can't the editor on the Ideas site behave like the forum here?

[v-gchenna-msft]

Hi @Element115 ,

Apologies for the issue you are facing with editor. Each site is maintained by different teams in Microsoft, so it's difficult to tell what could be the reason for this performance. I will share this feedback with the team. 

Glad that you shared your query over here. Please continue using Fabric Community for your further queries.

Hope this is helpful.