Q1 A file of 4096 blocks is to be sorted with an available buffer space of 64
blocks. How many passes will be needed in the merge phase of the external
sort-merge algorithm?
Q2 Consider the following SQL query
SELECT E.Lname AS Employee_name, S.Lname AS Supervisor_name
FROM EMPLOYEE AS E, EMPLOYEE AS S
WHERE E.Super_ssn=S.Ssn;
(a) Draw at least two query trees that can represented each of that query.
Under what circumstances would you use each of your query trees?
(b) Draw the initial query tree for each of that query; then show how the
query tree is optimized by the algorithm outlined in section 19.7.
(c) Compare your on-query trees of part (a) and the initial and
final query trees of part (b).