My DataFlow Gen 2 Fails with Unknown Evaluation Error 999999 (Request ID: fcd89914-0dd9-44ea-9b09-94

[sholy29]

I do not understand why the Dataflow gen 2 is too buggy. This should be a revolutionary product from Fabric but it just cannot work without errors all the time.

I have a dataflow gen 2 that takes data from a lakehouse and transforms it and saves it in a destination. It has been working very fine for some few days, now it does not work baut instead shows this error. Error Details: We encountered an error during evaluation. Details: Unknown evaluation error code: 999999 (Request ID: fcd89914-0dd9-44ea-9b09-940f84fa6e3e).

The erroe message is very vague. Yes, I have access to the undelying data. The lakehouse it connects to has shortcuts from mirroring SQL Server. I do have access to this shortcut lakehouse data.

Can any one help me with this ?

[v-prasare]

This issue has been acknowledged and is now listed in the Known Issues Tracker under the title:
"Refreshes running slower or timing out for Dataflows Gen 2.0 with CI/CD."

As the issue is already known and being monitored, we are closing this conversation since no further action is required at this point. For any new queries or updates, please feel free to raise a new thread in the Fabric Community Forum: https://community.fabric.microsoft.com/

Thanks again for your participation in the Fabric Community Forum!

[Alven]

Hi @sholy29,

from a quick look to the telemetry for the Request ID you shared, I see that some of your queries with staging enabled got a problem which seems linked to a Microsoft Entra ID token: if the error persists, please raise a support ticket.

Worth mentioning that, given your dataflow is writing to destinations, I assume that you do not need to stage such queries: if that's the case, you can try to uncheck the "Enable staging" option (see picture below) for all of them and re-run the dataflow by clicking "Save & run"

Best regards,

Alessandro

[sholy29]

Thanks Alessandro.

I do have many queries that are not writing to a destination. I need those queries because I need to merge (join) them (denormalise) with other queries to have the final ouput table that then writes to a destination. I noticed that it is those queries without a destination that has staging enabled by default. 

Could this be the cause of the problem? Should I disable staging for the queries without destination?

Thank you

[Alven]

Hi @sholy29,

staging such queries could be useful in some cases for performance reasons (see Data in Dataflow Gen2 staging - Microsoft Fabric | Microsoft Learn and Best practices for creating a dimensional model using dataflows - Power Query | Microsoft Learn), but it really depends on the kind of transformations and how big the datasets of such queries are. 

The issue you reported should not happen, and if it persists consider raising a support ticket. But, as a workaround, you can uncheck the "enable staging" option for such queries and see if

1. dataflow refresh succeeds
2. the running time of the dataflow refresh does not increase significantly because the dataflow does not use staging anymore

Best regards,

Alessandro

[sholy29]

Honestly, I disenabled the staging and still did not work. I removed all of the queries and brought them again and this time it worked. Howerver, I got anothe issue, the dataflow that took two minutes to finish now take 18 minutes for the same query as before and no addtional transformation step. I am really confursed. This is not the 3rd time dataflow gen 2 ci/cd has been given me issues.

[v-prasare]

Hi @sholy29,

We are following up once again regarding your query. Could you please confirm if the issue has been resolved through the support ticket with Microsoft? If the issue has any update, we kindly request you to share the resolution or key insights here to help others in the community.

I’d encourage you to submit your detailed feedback and ideas via Microsoft's official feedback channels, such as the Microsoft Fabric Ideas.

Feedback submitted here is often reviewed by the product teams and can lead to meaningful improvement.

Thank you for your understanding and participation.

[sholy29]

Hi v-prasare,

Unfortunately the issue was not resolved by the support ticket. Currently, the daflow refresh that ususlly takes 2 min now takes atleast 18 min to refresh. I am confused on what happened and why the high refresh time

[v-prasare]

Hi @sholy29,

This has been added to known issues list. PFB URI for tracking this issue

Known Issues Tracker - Refreshes running slower or timing out for Dataflows Gen 2.0 with CI/CD

Thanks,

Prashanth Are

MS Fabric community support

If you find my response useful, please mark it as "Accept as solution" and click "Yes" if you found it helpful.

[v-prasare]

Hi @sholy29 ,
Thanks for reaching MS Fabric community support

In this case please consider raising a support ticket for further assistance. To raise a support ticket with request Id and other details for Fabric and Power BI, kindly follow the steps outlined in the following guide:

How to create a Fabric and Power BI Support ticket - Power BI | Microsoft Learn

Thanks,

Prashanth Are