The indexed nested-loop join algorithm described in Section 13.5.3 can be inefficient if the index is a secondary index, and there are multiple tuples with the same value for the join attributes. Why is it inefficient? Describe a way, using sorting, to reduce the cost of retrieving tuples of the inner relation. Underwhat conditions would this algorithm be more efficient than hybrid merge–join?
Answer to relevant QuestionsEstimate the number of block accesses required by your solution to Exercise for r1 Θ r2, where r1 and r2 are as defined in Exercise.Design sorting based and hashing algorithms for computing the division operation.Show how to derive the following equivalences by a sequence of transformations using the equivalence rules in Section 14.3.1. a. σθ1 ∧ θ2 ∧ θ3 (E) = σθ1 (σθ2 ...Describe how to incrementally maintain the results of the following operations, on both insertions and deletions.a. Union and set differenceb. Left outer joinConsider the following two transactions: T1: read (A); read (B); if A = 0then B: = B + 1; write (B). T2: read (B); read (A); if B = 0 then A: = A + 1; write (A). Let the consistency requirement be A = 0 ∨ B = 0, ...
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