Question

Question: a) Describe the process of query optimization with the help of an appropriate example.

b) What is the difference between built-in function and used defined function? Give any two examples of both.

(Advanced Database Systems Course)

Answer 1

The query optimizer uses disc I/O, CPU utilization, and memory usage as units of effort. For example, if the plan for query A has a lower cost than the plan for query B, then the following outcomes are possible: A executes faster than B, A executes slower than B or A executes in the same amount of time as B