Custom Column using Power Query or DAX New column

[Anonymous]

Hi all,

I have a doubt about the next question. Which is better in terms of performance, Custom Column using PQuery or New Column using DAX?

Thanks to all for you answer. 

[Greg_Deckler]

Well, overall, Power Query is only going to execute the calculation once per a query refreshing, so you will take a small performance hit during query refresh but after that you have a static value. With DAX, the calculation will essentially be done every time it is needed so you will have a performance hit each time.

[Anonymous]

Ok, thanks so much for your fast answer.

I have a model and i need to split some string values from various columns to use later like slicers. The fact table in the model have more than a million of rows and i'm thinking in transform my new DAX columns in Power Query columns to reduce the performance impact when the user use it.

Do you think i should do it?

Thanks again.

[Greg_Deckler · Accepted solution]

Yeah, I would say that in your case you should definitely consider moving that to Power Query. General rule is that the further upstream that you can push the calculations, the better the performance downstream.

[Anonymous]

Yes, I thinked the same.

If somebody need it, here you have a link that explain so well my first question:

http://radacad.com/m-or-dax-that-is-the-question

Thanks Greg_Deckler