File sizes increasing after uploading to and then downloading from the service.

[Anonymous]

Hi,

A collegue has noted that Power BI file sizes (.pbix) were increasing after uploading to and then downloading from the service. This is despite no changes to the report or data being made. I ran a couple of tests to investigate.

I first tested using Excel data.

    Initial saved as pbix: 42KB

    Initial saved as pbit: 12KB

    pbix after uploading and downloading from service

    1st time: 430KB

    2nd time: 430KB

    3rd time: 430KB

    Saving as pbit after 3rd time: 12KB

I tested again using a ODBC connection.

    Initial saved as pbix: 584KB

    Initial saved as pbit: 11KB

    pbix after uploading and downloading from service

    1st time: 1,787KB

    2nd time: 1,787KB

    Saving as pbit after 2nd time: 11KB

Going by what I've found is seems clear that uploading to the service and then downloading the .pbix results in an increase in file size which varies dependant on file size. Once this has been done initially the file size does not appear to change.

Does anyone know why this occurs? Can it be avoided?

Thanks and Kind Regards,

Calvin

[v-lili6-msft]

hi, @Anonymous 

When downloading the PBIX, the Power BI service has to rebuild the PBIX from scratch again.

There is maybe some little operation affect the size of new pbix file. This aThere is very little difference in size.

Best Regards,

Lin

[Anonymous]

Hey Lin, 

Do you know any more about the process that is occuring?

In the second instance the file size more than doubled. Surely if this scales with file sizes then this could be quite a significant difference, especially if repeated.

Thanks,

Calvin