Consider the join ,
given the following information about the relations to be joined. The cost metric is the number of page I/Os unless otherwise noted, and the cost of writing out the result should be uniformly ignored.
Relation R contains 10,000 tuples and has 10 tuples per page.
Relation S contains 2,000 tuples and also has 10 tuples per page.
Attribute b of relation S is the primary key for S.
Both relations are stored as simple heap files.
Neither relation has any indexes built on it.
52 buffer pages are available.
1. What is the cost of joining R and S using a page-oriented simple nested loops join? What is the minimum number of buffer pages required for this cost to remain unchanged?
2. What is the cost of joining R and S using a block nested loops join? What is the minimum number of buffer pages required for this cost to remain unchanged?
3. What is the cost of joining R and S using a sort-merge join? What is the minimum number of buffer pages required for this cost to remain unchanged?
4. What is the cost of joining R and S using a hash join? What is the minimum number of buffer pages required for this cost to remain unchanged?
5. What would be the lowest possible I/O cost for joining R and S using any join algorithm, and how much buffer space would be needed to achieve this cost? Explain briefly.
6. How many tuples will the join of R and S produce, at most, and how many pages would be required to store the result of the join back on disk?
7. Would your answers to any of the previous questions in this exercise change if you are told that R.a is a foreign key that refers to S.b?