Error exporting vpax file

[stepanov-a-o]

Hi! I installed the latest version of the model documenter, tried to run it, and I get the following error. See below.

A connection could not be made to the data source with the Name of '{"protocol":"tds","address":{"server":"bc1dartprod.database.windows.net","database":"bc1dartprod-1"},"authentication":null,"query":null}'.
The XML for Analysis request timed out before it was completed. Timeout value: 3600 sec.
Error 0x0003: Error exporting vpax file.

[marclelijveld]

Hi @stepanov-a-o

Sorry to hear you run into an error. Can you elaborate a bit on the solution where you tried to run the model documenter? Cause the database connection is most likely your data source used in the model. Did you use a Direct Query connection? Or anything specific less common?

Thanks!
--Marc

[stepanov-a-o]

Hi @marclelijveld !

Thank you for your reply. I tried to use the model documenter on a remote desktop (Azure VM). I have one data source - Azure SQL Database, and I use import and direct query modes.

Any ideas or suggestions on what to try/how to debug?

Thanks a lot.

Anton

[marclelijveld]

Hi @stepanov-a-o

Its a weird issue... since the database should not be reached by the Model documenter. However, this error says it could not reach your database... Can you provide me some details, such as:

• Are you working with a pbix of pbit?
• Did you already hit close and apply, so the data is loaded in your model?
• Which version of Power BI dekstop are you running?
• Just to be sure, it is a model loaded on Power BI desktop, not a remote model in the PBI Service?

Part of the Model Documenter is to generate a VPAX file, which now fails for some reason. To check where the error comes from, can you please take the following steps to see what is going on.

• Can you pleas run DAX Studio. You can download it here
• In DAX Studio, please connect to your Power BI Desktop file, or run it directly from the External Tools ribbon in Power BI Desktop
  
• Then, in DAX Studio go to the Advanced tab in the top ribbon and please click Export Metrics
  

It can take a while before the VPAX file is generated and saved, depending on model size and complexity.
More over, if you're new to DAX Studio please check if the following option is enabled before Exporting Metrics.
File > Options > Advanced

Let me know if you succeed in these steps!
Thanks :)
--Marc

[stepanov-a-o]

Hi @marclelijveld,

Thanks for the quick reply! See my comments below.

1. pbix file
2. Yes, the data loaded to the model
3. I had version 2.99.621.0 (November 2021), and I updated Power BI to the latest version yesterday. Tried to run the Model Documenter after the update. However, the result was the same.
   
4. The model is on my machine, i.e. the Power BI desktop.

I tried to generate the VPAX file as you suggested, and I got the following error.

I think my issue is related to the size of the model. I will try to increase the timeout and see if it helps. In the meantime, let me know if you have any other suggestions.

Regards,

Anton

[marclelijveld]

Hi @stepanov-a-o

Thanks for providing the details. Sounds odd, but I'm happy to see the same experience is there when you run it from DAX Studio. The Model Documenter is using the VPAX engine that is also used in DAX Studio, so I also expected this to happen. I'm happy cause there is nothing in the Model Documenter that broke this thing apparently :)

Though, that did not fix your issue yet. Can you try one more thing for me...
If you build a new Power BI model, where you use the same dataset, but only a few tables for example, so you have a smaller set of data. Can you try to run the Model Documenter on that model, to see if your model size is influencing this, or maybe something else? As you implied yourself already, model size might be an issue. What is the size of your file if I may ask?

Thanks!
--Marc

[stepanov-a-o]

Hi @marclelijveld

Sorry for the late reply. During my test, the size of the original pbix file was 1.87GB.

After that, I tried to load a subset of data (the reduced pbix file size was 584 MB) and ran the Model Documenter again. Unfortunately, I got the same error as before.

Last but not least, I tried to run the model documenter on another (new, small pbix file size) report, and it works as expected.

BTW, great initiative! Please keep this project going! :-)

Regards,

Anton

[stepanov-a-o]

@marclelijveld, an important note: all reports have the same data source - the Azure SQL database.

[marclelijveld]

Hi @stepanov-a-o
thanks for circling back! Interesting to see that generating the vpax file does not work with such large files. I'll try to figure out if this is a known limitation or anything.

At this point in time, there is not much more what I can do, other than suggesting to limit the number of rows before generating the model documentation. That should make the model size smaller and you can at least document the Power Query code, DAX expressions, security roles and model structure.

I will follow up when I have more information.

--Marc

[stepanov-a-o]

@marclelijveld, thanks for your feedback! I will also share an update if I have any other findings. Anton