The alternative between import mode and DirectQuery in Power BI will depend on whether the performance or currency of data is the most vital for aggregation line customer transaction data at three levels (daily, monthly, and annual).
- Import Mode (Recommended for Performance)
Benefits:
Faster query performance, as the data lives in memory.
Optimized for aggregation over large datasets.
Allows advanced DAX calculations and complex transformations.
Trade-offs:
A refresh will update reports, which may not be suitable for garnering real-time insights.
Large datasets may share the memory.
- DirectQuery (Most Preferred if Real-time Data)
Benefits:
Almost real-time updates are achieved by querying the source database.
Applicable to situations where data changes happen all the time.
Trade-offs:
Slower because of queries executed at runtime.
Limited ability to perform complex DAX calculations and transformations.
Best Choice?
Import Mode: This is for performance and responsiveness concerns. DirectQuery: We need to use real-time access to data but would have to make sure that the underlying databases are optimized enough to be queried. Hybrid (Composite Model) to combine both worlds of import top-level aggregations and, on the other hand, real-time transactional data in DirectQuery.
