Chapter 22, Problem 8PE

Explanation of Solution

Efficient ways to minimize or avoid repartitioning:

• The aggregate can be computed for each node locally without making any repartitioning.
• The partitioning on s.B implies to the partitioning on s.A,s.B.
• Understanding why the partitioning on the (A,B) required that tuples to be with the same value for (A,B) is that it should be in the same partition.
• Partitioning made just on B by ignoring A will also need to satisfy the requirement...