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S_loke's avatar
S_loke
Advocate I
7 years ago
Solved

Query folding using Dataflow as datasource - Is it possible? On Roadmap?

Similar to the issues reported on https://community.powerbi.com/t5/Desktop/Dataflows-don-t-support-Query-Folding/td-p/673500  Unfortunately, the tread seem to have gone into different direction, prov...
Dataflow
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  • Anonymous's avatar
    Anonymous
    7 years ago

    HI S_loke ,

    Based on test, I haven't found that option on dataflow side and it means this feature still not available on dataflow.
    In addition, I also checked plan list but haven't found it. You can consider to submit an idea to increase priority of this feature.

    What’s new and planned for business intelligence

    Regards,

    Xiaoxin Sheng

Lunar_sea's avatar
Lunar_sea
Frequent Visitor
6 years ago

Hi Microsoft,

 

I'm also looking for an offical update with respect to Query Folding for dataflows.

  • samloud's avatar
    samloud
    Frequent Visitor
    6 years ago

    I'd really like this too. But how coudl it be done? isn't a dataflow just a text file on Azure Data Lake under the covers? I can see how you'd fold back to a relational dB, and (especially if your indexes / partitions were set up nicely in the back end) it would limit the rows at source. But how would you do that against a file on ADLS?

     

    I wonder if they'd do something like a DirectQuery, where you'd target the Dataflow, but it would really fold the query back to the relational store behind the dataflow...

    • S_loke's avatar
      S_loke
      Advocate I
      6 years ago

      Hi,

       

      I guess this is where the new engine kicks in.  The whitepaper suggest that when using dataflows, there are instances of SSAS that are deployed in the backend so in theory you could do query folding against that instance.  The question now is how to trigger this because it is a temporary instance.  So far in my testing, i haven't been able to isolate the steps to take advantage of this but hopefully more information will come through to assist in the near future.

      • nickyvv's avatar
        nickyvv
        Most Valuable Professional
        6 years ago

        Matthew Roche has an excellent post about Query Folding and Dataflows:

        https://ssbipolar.com/2019/10/12/power-bi-dataflows-and-query-folding/

        The summary:

        1. When accessing dataflow entities from Power BI Desktop, no query folding takes place, even if the enhanced compute engine is enabled.
        2. When accessing dataflow entities from other entities in the Power BI service, no query folding takes place unless the enhanced compute engine enabled.
        3. When accessing dataflow entities from other entities in the Power BI service, query folding will take place when the enhanced compute engine is enabled, because the linked entity’s query will be executed against the cached data in SQL, rather than the underlying CDM folder.