SQL Query working on Datamart but not on Fabric Warehouse

[MBAKU]

I have an SQL query in a powerbi dataflow that is working when it is connected to a datamart. I need to migrate it to a fabric warehouse but when I change the source to the fabric warehouse the preview will not load and will just say "Evaluation Cancelled" and when I try to save the dataflow it will not save. 

[v-tejrama]

Hi @MBAKU ,

Thank you @Thomaslleblanc  for the response provided!

Has your issue been resolved? If the response provided by the community member addressed your query, could you please confirm? It helps us ensure that the solutions provided are effective and beneficial for everyone.

Best Regards,
Tejaswi.
Community Support

[v-tejrama]

Hi @MBAKU ,

I wanted to check if you had the opportunity to review the information provided. Please feel free to contact us if you have any further questions.

Thank you.

[Thomaslleblanc · Accepted solution]

What you’re seeing (“Evaluation Cancelled” in Dataflow Gen2 when you switch from Datamart to Fabric Warehouse) is usually a mix of:

1. Power Query Online’s preview/evaluation time limit being hit (10‑minute evaluation window) and/or
2. T‑SQL differences between Datamart and Warehouse that prevent the query from returning schema quickly enough to validate.

[ssrithar]

Hi @MBAKU ,

This is a very common migration issue from Datamart → Fabric Warehouse, and it’s not caused by Dataflow itself.
Your query is valid in Datamart, but Fabric Warehouse has a different SQL engine and execution model, and Dataflow Gen2 is far less forgiving when previewing.Datamarts and Fabric Warehouses do NOT use the same SQL engine, even though both look like “SQL endpoints.

So a query that runs in Datamart can:

• Timeout

• Fail planning

• Get canceled
  when evaluated by the Fabric Warehouse engine.

That’s why Dataflow shows:

“Evaluation Cancelled”

This is not a syntax error — it’s an execution/planning failure.

Clear next steps for you

1. Test the SQL directly in the Warehouse endpoint

2. Identify unsupported constructs

3. Move complex logic into:

   • Warehouse views, or

   • Precomputed tables

4. Keep Dataflow Gen2 simple

If this post helps, then please appreciate giving a Kudos or accepting as a Solution to help the other members find it more quickly.
If I misunderstand your needs or you still have problems on it, please feel free to let us know. Thanks a lot!