pbiplintRules / Performance
Reduce usage of calculated columns that use the RELATED function
What it checks
Calculated columns whose DAX calls RELATED.
Why it matters
RELATED in a calculated column copies a value from the one side of a relationship onto every row of the many side. That is a lookup the source can do with a join, or Power Query with a merge, at load time and often folded to the source. Done in DAX it is computed row by row after load and stored without full compression, and the copied column then duplicates a dimension attribute, which REMOVE_REDUNDANT_COLUMNS_IN_RELATED_TABLES also flags.
How to fix it
Add the column in Power Query with Merge Queries, or join it in the source view. If the value is only needed inside a measure, use RELATED in the measure instead of storing a column.
Quirks
- RELATEDTABLE( does not match; the pattern requires a parenthesis right after RELATED.