Forum Discussion

Hieudao's avatar
Hieudao
Frequent Visitor
9 months ago
Solved

Power BI Custom Visual – update() function resets dataView to 30k rows after drill up/down

Hi everyone, I'm developing a custom visual for Power BI, and I’m encountering an issue related to fetchMoreData() and the update() lifecycle when using drill up / expand down. --------------------...
Need Help
  • v-aatheeque's avatar
    v-aatheeque
    9 months ago

    Hi Hieudao 

    Thanks for sharing such detailed explanation.
    The configuration confirms that Power BI is applying a windowed data reduction of 30,000 rows. This behavior is by design in Power BI.

    When you drill up/down or navigate back to the page, Power BI reinitializes the visual and sends a fresh dataView starting from the first 30k rows. Even if you previously fetched all rows (105k), the visual does not persist that state across page navigation.

    The inconsistent columns/rows you observed (6 columns → 5 columns, 30k rows → 52k rows → back to 30k rows) happen because drill changes alter the schema (columns).

    To fix fetching data:

    In update(options), check options.type:
    If VisualUpdateType.All or VisualUpdateType.Data → clear previous cache and start fetching again.
    Always assume update() after drill or navigation is a fresh start.

     

    Hope this helps !!

    Thank You

Hieudao's avatar
Hieudao
Frequent Visitor
9 months ago

Hi everyone,
I am developing a Power BI Custom Visual and am getting a dataView related error when the user goes to page navigation and then back:

Symptom:

  • When the user drills down/up on the visual, Microsoft Fabric/Power BI returns the wrong dataView — specifically, it only returns a maximum of 30,000 rows, even though the original dataset is larger and the visual was displaying correctly before.
  • The error only occurs after changing pages (e.g., from Page 1 to Page 2 and then back to Page 1).
  • Before changing pages, the visual works normally (drill up/down returns correct data).

Video Bugs: https://drive.google.com/file/d/1ucCUaHpmQ06V6noZtgaqIBHSX9mQwPeN/view?usp=drive_link
Image: 

More details about the error: https://community.fabric.microsoft.com/t5/Developer/Power-BI-Custom-Visual-update-function-resets-dataView-to-30k/td-p/4872336. 
I need help. Thanks for watching. If you know, please help me.
Thanks.