Intermittent Excel export error in Power BI Service (Current Layout) with DirectQuery to Oracle

Hi yui_ ,

Thank you for reaching out to fabric community.

Microsoft hasn't published detailed documentation describing the internal implementation of the Excel export pipeline (for example, the exact sequence of DAX execution, DirectQuery translation, and Excel file generation). However, the official documentation does describe the supported export behavior and the key limitations.

For DirectQuery semantic models, Power BI retrieves data from the underlying data source at query time, so exporting a visual requires Power BI to execute the queries needed to obtain the data being exported before generating the Excel file. The export operation is therefore dependent on the performance of both the semantic model and the underlying DirectQuery source. Microsoft also documents limits for DirectQuery exports, including a 16 MB uncompressed data limit, which can result in fewer rows being exported than the maximum supported row count.

The Microsoft Learn documentation related to exporing data in power bi : 

https://learn.microsoft.com/en-us/power-bi/connect-data/desktop-use-directquery 

https://learn.microsoft.com/en-us/power-bi/visuals/power-bi-visualization-export-data?tabs=powerbi-desktop 

Thanks!!