Forum Discussion
Difference between data flow gen and Pipeline Data Flows
For some reason I yet want to understand the difference between
Fabric Data Flow gen 2 and Pipelines Data Flows in Fabric.
Which want to use?
8 Replies
- XhevahirMehalla
Helper IV
Thanks this helps a bit.
We have 94 Pipelines in Synapse and all have copy activity to start and then many steps to transformw which uses Mapping data flow.
We are planning to migrate to fabric and some data flows are so large and we 100s of steps and I am thinking how can we deal with them.
Will they migrate the Data flow gen 2 or we need to conver them into Spark/Notebooks.
Any tips here?
- v-abhinavmu
Community Support
Hi XhevahirMehalla,
Thanks for reaching out to the Microsoft Fabric Community forum.Given your 94 Synapse pipelines with complex Mapping Data Flows, I’d recommend evaluating Fabric’s built-in migration experience for Mapping Data Flow (MDF) transforms in Dataflow Gen2 before considering a complete rewrite using Spark notebooks.
Microsoft Fabric supports migrating eligible Synapse and Azure Data Factory pipelines, converting supported Mapping Data Flows into MDF transforms while migrating the pipeline and transformation logic together.
However, MDF transforms are currently in public preview, and not all Mapping Data Flow capabilities are supported. I’d suggest testing a few representative flows first and validating their compatibility, transformation results, and performance. For flows that rely on unsupported capabilities, alternatives include Spark notebooks, Power Query in Dataflow Gen2, or Warehouse SQL, depending on the requirements.
For more details, please refer to the below Official Microsoft Documentation:
• Mapping Data Flow Transforms in Dataflow Gen2 (Preview) - Microsoft Fabric | Microsoft Learn
• Upgrade Best Practices for Azure Data Factory to Fabric Data Factory - Microsoft Fabric | Microsoft Learn
• Fabric decision guide - copy activity, dataflow, Eventstream, or Spark - Microsoft Fabric | Microsoft LearnI hope this helps. Please feel free to reach out if you have any further questions.
Thank you.
- jubinsoni
Resolver II
Hi XhevahirMehalla,
I think the earlier replies already cover the basics, so I will add the part that usually decides which one to pick in practice.
The two are not really competing options. A Dataflow Gen2 is a Power Query transformation item, while a pipeline is the orchestrator and its Copy activity is the bulk mover. A pipeline can also call a Dataflow Gen2 through the Dataflow activity, so they are often used together.
The choice normally comes down to transformation shape, data volume and who will maintain it. Microsoft summarizes the trade-offs in its Fabric decision guide
A simple way to think about it is like this
move data as is, large volume -> pipeline Copy activity reshape, join, clean with a low code UI -> Dataflow Gen2 heavy custom logic or very large transforms -> notebook, called from a pipelineTwo practical points are worth checking. A Dataflow Gen2 consumes capacity based on the Power Query engine run time, so a heavy refresh can cost more than a Copy activity doing the same movement, and staging also adds storage and an extra hop. It also helps a lot if your source steps fold back to the source, because then the work happens upstream and not in the mashup engine.
So I would start with a pipeline Copy activity for ingestion, add a Dataflow Gen2 only for the shaping steps that really need Power Query, and move that part to a notebook if the volume grows.
AI-assisted drafting: AI was used to help structure and phrase this response. I reviewed and validated the technical content before posting.
- Shai_Karmani
Super User
They solve different problems, so you usually pick one based on what you need rather than one being better than the other.
Dataflow Gen2 is a transformation tool. It uses Power Query online, so you work visually with steps (filter, join, pivot, custom columns, M code). It is best when you need to shape data, clean it, combine sources, or expose a reusable transformed table. It writes results into a Lakehouse, Warehouse, SQL DB, or back as a dataflow queryable from Power BI. It is slower per row than a pipeline copy, but far easier to author transformations in.
Pipelines in Fabric Data Factory are an orchestration tool, almost identical to Azure Data Factory. The main data-moving activity inside a pipeline is Copy Data, which does source-to-sink movement at very high throughput but with little or no transformation. Pipelines also run notebooks, stored procedures, Dataflow Gen2 activities, foreach loops, triggers, and so on.
In practice: if you are just moving data from A to B with no reshaping, use a pipeline with the Copy Data activity because it is the fastest. If you need to shape, join, or cleanse before loading, use Dataflow Gen2. If you need both, use a pipeline that first runs Copy Data for bulk ingestion, then calls a Dataflow Gen2 (or a notebook) for transformations.
Also note the two write differently to a Lakehouse. Dataflow Gen2 writes to the Delta table through the Power Query engine, while a pipeline Copy writes files or Delta directly. For very large volumes, a pipeline Copy or a notebook is usually faster than a Dataflow Gen2.
If this helped, a thumbs up and marking it as the accepted solution would be appreciated.
Thanks,
Shai Karmani - NandanHegde
Super User
AvdBerg Just FYI Mapping dataflow of ADF/Synapse equivalent is now available within Dataflow gen2
Mapping Data Flow Transforms in Dataflow Gen2 (Preview) - Microsoft Fabric | Microsoft Learn- AvdBerg
Advocate I
NandanHegde Awesome, Thank you!
- AvdBerg
Advocate I
When you are saying "Pipeline Data Flows" do you mean the Dataflow activity you drop onto a Data Factory pipeline canvas in Fabric. That activity has no transformation engine of its own, it just points at and triggers a Dataflow Gen2 item you've already built. Same Power Query engine, just orchestrated inside a bigger workflow alongside Copy, Notebook, Stored Procedure, and so on. There is no standalone "Mapping Data Flow" activity in a Fabric pipeline.
Did I answer your question, please mark the post as a solution or consider a like.
- NandanHegde
Super User
Can you be more specific on what you mean by data flow in Pipeline?
Basically Dataflow gen2 is low code way of doing transformations within MSFT Fabric with underlying transformation across Power Query. You can explicitly trigger/schedule a dataflow gen2 but you can also trigger it via dataflow activity within Fabric data pipeline.