Consider a relation with the following schema: Executives (id: integer, name string, title:string, level: integer) The Executives relation consists of 100,000 tuples stored in disk pages. The relation is stored as simple heap file and each page stores 100 tuples. There are 10 distinct titles in the Executives hierarchy and 20 distinct levels ranging from 0-20 Suppose that the following SQL query is executed frequently using the given relation: SELECT E.ename FROM Executives WHERE Etitle"CEO and E.level > 15 Your job is to analyze the query plans given below and estimate the cost of the best plan utilizing the information given about different indexes in each part. a) Compute the estimated result size and the reduction factor (selectivity) of this query (1 mark) b) Compute the estimated cost of the best plan assuming that a clustered B+ tree index on (title, level) is (the only index) available. Suppose there are 200 index pages, and the index uses Alternative 2. Discuss and calculate alternative plans. (1 mark) c) Compute the estimated cost of the best plan assuming that an unclustered B+ tree index on (level) is (the only index) available. Suppose there are 200 index pages, and the index uses Alternative 2. Discuss and calculate alternative plans. (1 mark) d) Compute the estimated cost of the best plan assuming that an unclustered Hash index on (title) is (the only index) available. The index uses Alternative 2. Discuss and calculate alternative plans. (1 mark) e) Compute the estimated cost of the best plan assuming that an unclustered Hash index on (level) is (the only index) available. The index uses Alternative 2. Discuss and calculate alternative plans. (1 mark) Consider a relation with the following schema: Executives (id: integer, name string, title:string, level: integer) The Executives relation consists of 100,000 tuples stored in disk pages. The relation is stored as simple heap file and each page stores 100 tuples. There are 10 distinct titles in the Executives hierarchy and 20 distinct levels ranging from 0-20 Suppose that the following SQL query is executed frequently using the given relation: SELECT E.ename FROM Executives WHERE Etitle"CEO and E.level > 15 Your job is to analyze the query plans given below and estimate the cost of the best plan utilizing the information given about different indexes in each part. a) Compute the estimated result size and the reduction factor (selectivity) of this query (1 mark) b) Compute the estimated cost of the best plan assuming that a clustered B+ tree index on (title, level) is (the only index) available. Suppose there are 200 index pages, and the index uses Alternative 2. Discuss and calculate alternative plans. (1 mark) c) Compute the estimated cost of the best plan assuming that an unclustered B+ tree index on (level) is (the only index) available. Suppose there are 200 index pages, and the index uses Alternative 2. Discuss and calculate alternative plans. (1 mark) d) Compute the estimated cost of the best plan assuming that an unclustered Hash index on (title) is (the only index) available. The index uses Alternative 2. Discuss and calculate alternative plans. (1 mark) e) Compute the estimated cost of the best plan assuming that an unclustered Hash index on (level) is (the only index) available. The index uses Alternative 2. Discuss and calculate alternative plans. (1 mark)
