Hi @SumitSingh , I assume you mean if you use a query based mapping, then Compose is not leveraging __CT tables. This is correct and because a query based mapping can really have anything in it (aggregates, windowed aggregates, correlated subqueries etc. etc.). It would be near impossible for Compose to be able to automate the use of CT tables in these scenarios. (For example if your query performed an aggregate over COUNTRY - if we simply moved to use CT tables, then the aggregate would be in-accurate).
Depending on what you are doing, it is sometimes better to leverage the Compose model to manage relationships between tables and allow Compose to automate the denormalization (i.e. joining) of tables when delivering data to the data mart.
You could also use other incremental load patterns (like a date-time /incrementing value or a processed flag) to process "changed data".
Using the model to represent these relationships and having Compose automate the denormalization is documented in a whitepaper - Modeling Real-time Data Warehouses in Compose
(Other Qlik Compose data warehouse whitepapers can be found here - https://community.qlik.com/t5/Labels-page/bd-p/Category_Labels?categoryId=data-integration-documents... )
Hope that helps.
