Dynamic Programming
•Step i: For each Q ⊆ {R1, …, Rn} of cardinality i do:
–Compute Size(Q)    (later…)
–For every pair of subqueries Q’, Q’’
s.t. Q = Q’ U Q’’
compute cost(Plan(Q’)       Plan(Q’’))
–Cost(Q) = the smallest such cost
–Plan(Q) = the corresponding plan