Issue with Dataflow Refresh from Oracle On-premise to Lakehouse - MashupException

[sammy1998]

Hello Community,

I am currently facing an issue when using Dataflow in Fabric to load data from an on-premise Oracle source into a Lakehouse. My workflow is as follows:

• I created several queries in a Dataflow with Oracle on-premise as the source and Lakehouse as the destination.
• The first run of the Dataflow works as expected: data is loaded successfully into the Lakehouse.
• Starting from the second run, all queries in the Dataflow fail to refresh, showing the following error message:
  Spoiler

  There was a problem refreshing the dataflow: 'Couldn't refresh the entity because of an issue with the mashup document MashupException.Error: Error in replacing table's content with new data in a version: #{0}., InnerException: #{0} failed to get contents from '#{1}'. Status code: #{2}, description: '#{3}'., Underlying error: AzureDataLakeStorage failed to get contents from ...

  If I delete the target table in the Lakehouse and rerun the Dataflow, the refresh is successful. However, on the next run, the same error occurs again.

  Has anyone experienced this issue or have any suggestions? What could be causing this error?

  Thank you!

[Anonymous]

Hi @sammy1998,

As we haven’t heard back from you, we wanted to kindly follow up to check if the solution provided for the issue worked? or Let us know if you need any further assistance?
If our response addressed, please mark it as Accept as solution and click Yes if you found it helpful.

Regards,
Vinay Pabbu

[Anonymous]

Hi @sammy1998,

As we haven’t heard back from you, we wanted to kindly follow up to check if the solution provided for the issue worked? or Let us know if you need any further assistance?
If our response addressed, please mark it as Accept as solution and click Yes if you found it helpful.

Regards,
Vinay Pabbu

[Anonymous]

Hi @sammy1998,

May I ask if you have gotten this issue resolved?

If it is solved, please mark the helpful reply or share your solution and accept it as solution, it will be helpful for other members of the community who have similar problems as yours to solve it faster.

Regards,
Vinay Pabbu

[Anonymous]

Hi @sammy1998,

Thank you for reaching out to Microsoft Fabric Community Forum.

This is expected behavior in Fabric. When a Dataflow tries to overwrite an existing Delta table in the Lakehouse, it can fail due to how Delta handles table state and locking. To avoid this, set the destination option to "Delete rows in destination table" instead of "Replace entire table." This ensures a clean refresh without triggering the mashup error.

If this post helps, then please consider Accepting as solution to help the other members find it more quickly, don't forget to give a "Kudos" – I’d truly appreciate it!

Regards,
Vinay Pabbu

[sammy1998]

Hi @Anonymous ,
In Dataflow Gen2, I don’t see the “Delete rows in destination table” option—only “Append” and “Replace” are available. Is there any way to enable this option or another recommended workaround?

Thank you!

[Anonymous · Accepted solution]

Hi @sammy1998,

The Delete rows in destination table option is available only in Dataflow Gen1, not in Dataflow Gen2

If you're using Dataflow Gen2 Use a Pre-step to Drop the Table Before Replace.

Regards,

Vinay Pabbu