1. Building Semantic Models in Oracle Analytics Cloud
  2. Create and Build Your Model
  3. Manage Logical Table Sources
  4. How Are Fact Logical Table Sources Selected to Answer a Query?

How Are Fact Logical Table Sources Selected to Answer a Query?

Oracle Analytics uses a specific criteria to select a fact logical table's sources to answer a query.

Every column in a query is sourced from a single logical table source based on the below criteria. Queries aren't load-balanced across multiple logical table sources.

After the fact logical table sources are selected, Oracle Analytics selects the best dimensional logical table sources to answer a query. See How Are Dimension Logical Table Sources Selected to Answer a Query?

The fact logical table source selection criteria is listed from the highest precedence to the lowest precedence:

  • Logical table source priority group - A higher priority fact logical table source group is used before a lower priority fact logical table source group, even if the higher priority source is at a more detailed grain. A lower group number indicates a higher priority. See About Assigning Logical Table Sources Priority Order.

  • The grain of the logical table source - If all fact table sources have the same priority number, then a higher-grain logical table source is used before a lower-grain logical table source.

  • Logical table source list order - If all other criteria are equal, then the first logical table source in the fact table's sources list is selected. This list is displayed in the logical table's Sources tab.