Power BI on complex data sources like an EPR system is a difficult task. Power Query delivers a nice set of functionality, but using it on millions of rows is not a comfortable way to denormalize your data. But this is a necessary task to create simple star schema data models. It is even harder to achieve a fast Power BI report if you need more than one complex data source. Bad data quality is often another challenge you have to face. I will show you a way to archive fast and reliable enterprise level Power BI reports.