Setting performance options for relationships
In the previous two sections, we looked at relationships and how they differ from joins. As relationships are dynamic, they can sometimes create queries that could be better optimized by telling Tableau more about our data.
Performance Options is available in the user interface under the field mappings, as seen in Figure 8.35:
Figure 8.35 – Performance options
In most cases, the best practice is to leave the default options as-is unless we are 100% sure of our data. Let’s look at these two settings and why the default is best:
- Cardinality: You can effectively use this to tell Tableau when a field is a unique key/index field. Using our example of product sales and the product catalog where product sales are on the left, we would want to leave Many on the left-hand side because a
Product IDcould be sold many times. If we were 100% sure we had no duplicates in our data – exactly...
