Consider the relation Student(Id,Major,Status), which has:
A clustered hash index on Major and no other indices.
100 pages of data spread over 50 majors.
The domain of Status has 9 values.
Find the best access path to evaluate the expression
Major=0CS0 OR Status=0U30 (Student)
and estimate the cost of using this access path.
Solution:
Since we have a disjunction, we need to evaluate Status=0U30(Student) anyway. This selection
requires a scan of the relation at the cost of 100 pages plus the cost of writing out the result.
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