broadcast.scala

val t0 = System.nanoTime()

// Create the Execution Plan
fact_table = fact_table.join(broadcast(dimension_table), // Here's the magic!
                         fact_table.col("dimension_id") === dimension_table.col("id"))

// Perform an action to run the execution
fact_table.count

val t1 = System.nanoTime()
println("Elapsed time: " + (t1 - t0)/10e8 + "s")