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Magazine Problem 1
Discuss the reasons for converting SQL queries into relational algebra queries before optimization is done.
Problem 4
What is meant by the term heuristic optimization? Discuss the main heuristics that are applied during query optimization.
Problem 5
How does a query tree represent a relational algebra expression? What is meant by an execution of a query tree? Discuss the rules for transformation of query trees, and identify when each rule should be applied during optimization.
Problem 6
How many different join orders are there for a query that joins 10 relations?
Problem 8
What is the difference between pipelining and materialization?
Problem 12
What is meant by semantic query optimization? How does it differ from other query optimization techniques?
Problem 14
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?
Problem 16
Develop cost functions for an algorithm that consists of two SELECTs, a JOIN, and a final PROJECT, in terms of the cost functions for the individual operations.
