The Cost of xVelocity Relationships
How expensive is an xVelocity relationship? The answer depends on several factors, such as column cardinality, DAX calculations, and query itself. But it general, a relationship can add a significant overhead. Consider two tables: Customer (7.1 million rows) and Account Snapshot (187 million rows) and a relationship ‘Account Snapshot'[CustomerKey] -> Customer[CustomerKey]. I’ll use two queries for the test. The Relationship query uses the ‘Account Snapshot'[CustomerKey]->Customer[CustomerKey] relationship, while the No Relationship query scans directly the Account Snapshot table bypassing the relationship.