SSAS Tabular Models converted to AtScale Automatically

[Greg_Deckler]

This is happening to old PBIX files that we haven’t touched in a while, that were originally built with an Analysis Services data source pointed to our server/data model.  In the present, we get a requirement to change something in the report, so we open them up, make the change, and then publish… the report throws an error in the service because an issue with the connection to the data.  We re-open the file to see that the Data Source has changed to AtScale.  We have caught this happening prior to making any changes or publishing, so I am like 90% sure that Power BI Desktop is mis-reading/mis-interpreting embedded connection/datasource metadata as this “AtScale” data source type, and we can’t convert it back once it happens.

Here is the Connection metadata for one of these PBIX files, last modified 6/16/23, before I open it in Power BI Desktop:

{"Version":3,"Connections":[{"Name":"EntityDataSource","ConnectionString":"Data Source=redacted;Initial Catalog=redacted;Cube=Model","ConnectionType":"analysisServicesDatabaseLive"}],"RemoteArtifacts":[{"DatasetId":"redacted","ReportId":"redacted"}]}

I open a copy in Power BI Desktop and look at the Data Source.  It still shows the SQL Server Analysis Services database dialog

Here is an example of an impacted file, last modified 3/11/24:

{"Version":3,"Connections":[{"Name":"EntityDataSource","ConnectionString":"Data Source=redacted;Initial Catalog=redacted;Cube=Model","ConnectionType":"atScaleDatabaseLive"}],"RemoteArtifacts":[{"DatasetId":"redacted","ReportId":"redacted"}]}

When opening the data source in Power BI the dialog is AtScale Models

We didn’t change the data source.  In fact, as you know, you can’t change the connection type from Power BI Desktop after it’s set… Get Data is grayed out.  All you can do is change the server and data model it’s pointing to by going into Data Source options.

See this thread: SSAS Tabular Model has been changed to AtScale mod... - Microsoft Fabric Community

[Anonymous]

Hi @Greg_Deckler 

According to your description, it should be that some update to PBI Desktop caused a change in the data source, changing Analysis Services Database to AtScale Database, and there is no way to modify it, right? I looked up some of the documentation for the update and didn't find anything about it. This may involve needing to access the PBI Desktop logs.

Due to the permissions issue, I suggest you can raise a Support ticket and a dedicated Microsoft engineer will come to solve the problem for you.

The link of Power BI Support: https://powerbi.microsoft.com/en-us/support/

For how to create a support ticket, please refer to https://community.powerbi.com/t5/Community-Blog/How-to-create-a-support-ticket-in-Power-BI/ba-p/6830...

Best Regards,
Community Support Team _ Ailsa Tao

[Greg_Deckler]

@Anonymous That's correct, seems that even if you save as a zip file, modify the connections file and save back as a pbix that the connection is still changed back automatically to AtScale. So something in Power BI Desktop changed and it likely happened in March or April update to Power BI considering when the problem was first reported in the linked post along with the last modification date that was cited above, 3/11/24 where the Power BI Desktop version was likely Febuary 24. @jtrock 

[jtrock]

Thanks, @Greg_Deckler ... I have raised support ticket 2408200040013528 with MS

[Greg_Deckler]

For anyone else having this issue here is the root cause and fix. It would be helpful if Microsoft could confirm which months this bug existed.

Root Cause

This issue was identified and fixed last year. We realized we were incorrectly classifying SSAS models as AtScale. The bug was in production for 1-2 months before being fixed and any live connected reports created during that time were being classified as AtScale. Up until AtScale integration was finished ~1-2mo ago, we were treating AtScale virtually the same as SSAS with no parameters added to the connection string - so no change in report behavior. Some of these reports could have been holding onto the AtScaleDatabaseLive connection type for the last year, and now after republishing, they're unfortunately catching the new WSID connection string parameter. This lines up with the the inability to reproduce the issue today and why new reports are working as normal, but the customer republishing existing reports causes the WSID property to appear and failure in gateway.

Fix

Saving the file as a .pbip (PBI Project) file, exposing the metadata for the connection and change it there (something you can't do in the PBI Desktop UI.)  Saving as a zip file, changing the Connection file there, and then resaving as PBIX just ends up as a corrupted file so that is not an available fix.