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powerbiexpert22's avatar
powerbiexpert22
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2 years ago
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Initial Stage of Development

i am at the initial stage of development, i am not sure whether i should go with import or direct query mode for fact tables, if i build reports using import mode with incremental refresh now and lat...
  • Ritaf1983's avatar
    2 years ago

    Hi powerbiexpert22

    I wasn't entirely sure if the question was about the types of data imports available or if there's a way to revert from an import to a direct connection. So I'll address both.

    As for the preferred method, the answer is:

    in Power BI, choosing between Import mode and Direct Query mode depends on several factors such as data size, refresh frequency, performance, and real-time reporting needs. Here's a breakdown of when to use each mode:

    Use Import Mode when:

    Data Size is Manageable:

    Your dataset can fit into Power BI's memory limits without performance issues.
    Import mode is ideal for smaller to medium-sized datasets.
    Performance Needs:

    You need fast query performance. Import mode caches the data, allowing faster visual rendering and interactions.
    Import mode often provides better performance compared to Direct Query, as it avoids the overhead of querying the data source each time.
    Data Refresh Frequency:

    Your data does not need to be real-time or near-real-time. You can schedule data refreshes at intervals that meet your business needs (e.g., daily, hourly).
    Data Transformation and Modeling:

    You need to perform complex data transformations, calculations, or modeling. Import mode provides more flexibility for data manipulation within Power BI.
    Advanced Analytics:

    You plan to use advanced analytics features, such as AI insights or advanced calculations, which may perform better with imported data.


    Direct Query Mode
    Use Direct Query Mode when:

    Large Datasets:

    Your dataset is too large to be imported into Power BI's memory. Direct Query mode is suitable for handling large volumes of data that are stored in robust data sources like SQL databases, Azure SQL, or big data platforms.
    Real-Time or Near Real-Time Reporting:

    You require real-time or near-real-time data updates. Direct Query mode queries the data source directly, reflecting the most recent data without needing scheduled refreshes.
    Data Security:

    Your data security policies require that data remains in the source system, and you cannot store a copy in Power BI.
    Data Source Performance:

    Your data source is capable of handling the query load efficiently. Direct Query performance is heavily dependent on the underlying data source's ability to execute queries quickly.
    Minimal Data Transformation:

    Your data requires minimal transformation and can be queried directly in its current form. Direct Query has limitations in terms of complex transformations and calculations compared to Import mode.
    Single Source:

    You are primarily using a single data source. While it’s possible to use multiple sources in Direct Query, it can complicate and potentially degrade performance.
    Summary
    Import Mode: Best for smaller datasets, faster performance, more flexible transformations, and non-real-time data needs.
    Direct Query Mode: Best for large datasets, real-time needs, strict data security requirements, and when the data source can handle query loads efficiently.

    There is a lot of text, so I recommend the linked video guides for easier understanding :
    https://www.youtube.com/watch?v=OtOdgmvTyVM

    https://www.youtube.com/watch?v=bdpsIwHPEzw


    According to the switch from import to direct, there is a workaround to do this, like in the attached video :
    https://www.youtube.com/watch?v=E0zRPk5Cmqw&t=61s

     

    However, there are many limitations, such as:

    PQ steps that DirectQuery doesn't support

    Some DAX commands

    Restrictions on visualizations etc...

    If this post helps, then please consider Accepting it as the solution to help the other members find it more quickly.