add more examples with data motion
I still need to figure out certain things on data motion, eg.:
- Why we have no motion if SELECT+EXCEPT includes the 'id' column, but 'full' motion with any other combination of columns?
- Is 'segment' motion available only for inserting tuples, or there is a way to have it also with SELECT+EXCEPT?
- So the 'full motion means the whole table is moving. Where it goes exactly within a simple router+storage setup?