An n-Way Join is a star join that can join a large table with multiple small tables in a single join step. An n-way join is especially useful for star schema query optimization when the fact table is a large columnar table and the dimension tables are small tables that are not joined to each other. Each small dimension table must also have a filtering condition. Unlike LT/ST optimization, n-way optimization can join the dimension tables directly to the fact table in a single step, without first joining the dimension tables.
n-way join optimization can significantly reduce CPU and spool consumption for star schema databases where the fact table is a columnar table.
For an example of n-way join optimization, see n-Way Join Example.