Dataflows: Merge functions store data twice?

[oneraj4u]

I am trying to understand how dataflows in Power BI Service store data.

If I append Table A to Table B to create Table C:
Do dataflows duplicate the data from A & B to create C and  store it twice thereby doubling the size of the data flow?

[TomMartens]

Hey @oneraj4u ,

there is a simple answer: yes!

Regards,

Tom

[oneraj4u]

Thank you for your response.
Can you point to the exact documentation that discusses this?
I haven't found it within Microsoft's PBI site.