Problem with reference table and refreshing

[Anonymous]

Hello,
I have a main table in my project (5mln rows)
I created second table which based on main table (I add here a few steps).

I thought, that when I refresh my project, then only main table downloading source and second table (reference) based on refreshed main table.

But if I click refresh then both tables downloading source (2x5mln rows).
Why ? 

[Anonymous]

Hi @amchitchandak

it still the same problem.
I created a new Query (call Query1) and put it:
=Table.Distinct(mainTable)

The new table is created.

But when I refresh my project both tables downloading data source.

[amitchandak]

@Anonymous , You might have done that duplicate or using the option add as new query.

In place of that you should create it using table function

example

Source = Table.Distinct(Table1)

Check power query table function:https://www.youtube.com/playlist?list=PLPaNVDMhUXGalVK1yOQ8hV2kWTNsZW5Gq

Or create in DAX using summarize or distinct