We learned about the benefit of QVD file that used to be loaded very fast and faster 10 to 100 times than other kind of data sources. So this is the best practice to extract the datasource directly and store it into ExtractedQVD file and if u want to transform the data, just load the data from ExtractedQVD and use any logic or any functions to transform ur data. Ans use this transformed QVD file as the final datasource u can load into the QS application. Because actually the data source loaded directly from server may encounter with the problem of network traffic. as well as Data structure is not typically changing so often. So this is the best practice to store data in QVD instead in order to improve the load speed.