•R is scanned once; each S group is scanned once per matching R tuple.
•Cost:
M log M + N log N + (M+N)
•But really, we can do it in 3(M+N) with some trickery.
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–The cost of scanning, M+N, could be M*N (unlikely!)
•With 35, 100 or 300 buffer pages, both Person and Purchase can be sorted in 2 passes; total: 7500. (75 seconds).
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