Mastering Microsoft Power BI

Import

The performance of an import mode dataset is largely driven by fundamental design decisions, such as the granularity of fact and dimension tables. For example, large dimension tables with more than a million unique values, such as customer IDs or product IDs will produce much less performant report queries than small dimensions with only 100 to 1,000 unique values. Likewise, DAX Measures that access columns containing thousands of unique values will perform much more slowly than measures that reference columns with a few unique values. A simplistic but effective understanding is that higher levels of cardinality (unique values) result in greater memory consumption via reduced compression and CPUs require additional time to scan greater ...