Consider a database with two tables, namely, Customer and Purchase. There are 4000 records in Customer table and 75000 records in Purchase table. One disk page can store 10 Customer records or 15 Purchase records. Assume that 202 memory pages are used as buffer. What are the IO cost (excluding IO cost to write results to disk) of the following join operations between Customer table and Purchase table (measured in the number of disk page accesses)? Which strategy appears to have the lowest cost?

Qa) Nested-Loop Join (Purchase is in the outer loop).

Qb) Nested-Loop Join (Customer is in the outer loop).

Qc) Partition-hash join.