MicroStrategy Developer assigns a size to every table in the project when you first add them to the project. These size assignments are stored in the metadata and are calculated based on the table columns and their corresponding attributes. Because Developer uses the conceptual or logical attribute definitions when assigning sizes, this measurement is known as the logical table size.
When you run a report, the Analytical Engine chooses the smallest of all tables, based on logical table size, that contains enough data to answer the query. The initial logical table size is based on the number of attribute columns and the various levels at which they exist in their respective hierarchies. For information on defining the logical table size of a table, see Defining logical table sizes.