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Raphael9999's avatar
Raphael9999
Regular Visitor
8 years ago

What is doing "Allow Data Preview To Download In The Background"

Hello,

 

I have a large Power Bi file: 36 tables, many relations, up to 103 columns and 7000 rows in the largest tables, with extensive data preparation in the query editor.  

My i5 CPU and 16Gb of RAM are screaming at each refresh. Though they have not yet melted :)

I have already worked quite a lot on the performance including "Disable load" on as many queries as possible, and several others tricks. 

 

I stumble upon this https://blog.crossjoin.co.uk/2016/12/05/power-query-power-bi-and-the-allow-data-preview-to-download-in-the-background-option/

 

I have disabled "Allow Data Preview To Download In The Background" and suddenly it runs very quickly... too quickly to be true. 

I have done some research on the internet but I did not find what does really happen when you disable the preview in the background. 

 

What am I loosing doing that?

Or what does the "data preview download in the background" is for?

Thank you

Raphael

Need Help
Tips and Tricks

4 Replies

  • Jia2023's avatar
    Jia2023
    New Member
    3 years ago

    The option "Allow data preview to download in the background" in Power BI Desktop refers to a feature that enables Power BI to download a preview of data in the background while you are working on your report. Enabling this option allows Power BI to fetch a subset of data from the data source and display it in the report preview area, even before you explicitly refresh the data.

    When you have a large dataset or complex queries, downloading the entire dataset for preview can take a significant amount of time and affect the performance of Power BI Desktop. By checking the "Allow data preview to download in the background" option, Power BI fetches only a portion of the data needed for the report, improving the overall responsiveness of the application.

    However, it's important to note that this option is related to data preview and not directly linked to clearing the visual and data engine cache. To clear the cache, you need to uncheck the "Allow data preview to download in the background" option.