Apply any changes in/from Power Query Editor takes hours.

[wraaesen]

When I either want to make or apply any changes in/from Power Query Editor, it takes hours, and the loading screen shows an unreasonable amount of data usage (see pictures of 4GB & 9,9GB).
I can't comprehend that my file, only containing test data and a few calculations, can be so heavy.
Load from ValidLP.LCYLoad from ValidLP.EUR
I have three tables:
A) Main table, "1 VA" (1200KB / 3000 rows)
B) Two Lookup tables, "5. ValidLP.EUR" & "5. ValidLP.LCY" (4000KB each /18000 rows)

I use a few Table.AddColumn together with the List.PositionOf function in the main table to do some lookup.

Not sure they could cause the problem.

Example:

     VA_Table 

Material

X

Y

Z

V

5 ValidLP.EUR

Material	ListPrice
X	10
Y	20
Z	30
V	40

= Table.AddColumn(#"Add brugerdefineret4", "ListPriceLookup", each #"5 ValidLP_EUR"[LP_EUR]{List.PositionOf(#"5 ValidLP_EUR"[Material],[Material])})

[Nintendo_Nerd99]

I am not sure which is faster.

Buffer your lists before the above step:

Buff_LP_EUR = List.Buffer(#"5 ValidLP_EUR"[LP_EUR])
Buff_Material = List.Buffer(#"5 ValidLP_EUR"[Material])

or this might suffice:

Table.AddColumn(#"Add brugerdefineret4", "ListPriceLookup", (outer) => Table.SelectRows(#"5 ValidLP_EUR", each [LP_EUR] = outer[Material])[Price]{0})