Regarding Synthetic keys/Synthetic Tables, the first recommendation is to read though this post
created by Henric Cronström.
QlikView may end up using excessive amount of time and/or memory when the number of composite keys/Synthetic Tables increase,
depending on data amounts, table structure and other factors. Unfortunately the actual limitations are virtually
impossible to predict, which leaves only trial and error as a practical method to determine them.
The best practice are below...
-. If they are UNINTENDED Synthetic keys/Synthetic Tables:
Please eliminate the Synthetic keys/Synthetic Tables as much as possible
-. If they are INTENDED Synthetic keys/Synthetic Tables:
Please do the performance test and find out the best data model based on the testing result.