< * Allow star join optimizations
<
< While our bitmap scan allows multiple indexes to be joined to get
< to heap rows, a star joins allows multiple dimension _tables_ to
< be joined to index into a larger main fact table. The join is
< usually performed by either creating a cartesian product of all
< the dimmension tables and doing a single join on that product or
< using subselects to create bitmaps of each dimmension table match
< and merge the bitmaps to perform the join on the fact table. Some
< of these algorithms might be patented.