Aggregation table in data model

[Oleg_F]

Hi.

Is it possible to create aggregation table (in data model), to improve speed, if all tables, also fact table(source), are in import mode in Power BI, or fact table must be only in direct query mode? 

Case:

I have fact table (in import mode) that is detailed to product and I have created aggregation table (import mode) in Power Query with details to category, that reduce data size in 4 times, create necessary relationships...

Using "Precedence" I want that my query (from visuals) firstly goes to aggregation table, but in Manage aggregations, connection to fact table (summarization-detail table) is unavailable (data formats in both tables - same). 

Thank You.

[Oleg_F · Accepted solution]

After a long search in the internet and a lot of videos, I have only one conclusion - aggregation tables are used to enhance performance while you are working with DirectQuery mode.
The answer is:
- No, fact table(source) must be in DirectQuery mode.

Thanks everyone for help.

[amitchandak]

@Oleg_F ,

refer :https://docs.microsoft.com/en-us/power-bi/desktop-aggregations

https://community.powerbi.com/t5/MBAS-Gallery/Aggregation-and-composite-model-Microsoft-Power-BI-fas...

[Greg_Deckler]

Yes

[Oleg_F]

@Greg_Deckler  clarify your answer:
a. Yes, it could be done if all tables are in import mode
b. Yes, fact table must be in direct query mode.

Thank You.

[Greg_Deckler]

Aggregation tables require composite mode is my understanding. So they work when you have a mix of DirectQuery and import or all import.