Because Azure SQL DW doesn't currently have replicated tables (update: it does now), what exactly happens during a BroadcastMove? Does one temp table per compute node get created and populated with the results of broadcast? Then do 60 queries (one query per distribution) get run to join to the broadcasted temp table?
I'm mainly just checking that a broadcast doesn't mean 60 temp tables get created.
A broadcast move copies the required data once per node not per distribution. Therefore the number of copies is dependant on the scale of your sql data warehouse. However, it is important to note that the broadcast happens in parallel. Therefore the elapsed time for the movement should be roughly the same at DW100 to DW2000. In that sense it is not actually material to the performance of the query.