Consider the join r ▷◁ s of two relations r and s whose common attribute set is {A}. Physically, r is stored on 25 blocks and s on 21 blocks on the disk, tuples in both relations are unordered. Assume that the buffer pool allocated for carrying out the join has 3 frames. Compare block nested-loop join against merge join in facilitating r ▷◁ s by analyzing their I/O costs. The I/Os for exporting the final joined results to the disk is called the reporting cost, which shall be excluded from the calculation of the I/Os of r ▷◁ s, because the reporting costs of both nested-loop join and merge join cancel each other out in the comparison. Specifically, (a) Compute the # of I/Os, excluding the reporting cost, engaged by block nested-loop join. (b) Compute the # of I/Os, excluding the reporting cost, engaged by merge join in the worst-case and best-case scenarios, respectively. Here a scenario indicates an instantiation of the tuples in r and s.
Consider the join r ▷◁ s of two relations r and s whose common attribute set is {A}. Physically, r is stored on 25 blocks and s on 21 blocks on the disk, tuples in both relations are unordered. Assume that the buffer pool allocated for carrying out the join has 3 frames. Compare block nested-loop join against merge join in facilitating r ▷◁ s by analyzing their I/O costs. The I/Os for exporting the final joined results to the disk is called the reporting cost, which shall be excluded from the calculation of the I/Os of r ▷◁ s, because the reporting costs of both nested-loop join and merge join cancel each other out in the comparison. Specifically, (a) Compute the # of I/Os, excluding the reporting cost, engaged by block nested-loop join. (b) Compute the # of I/Os, excluding the reporting cost, engaged by merge join in the worst-case
and best-case scenarios, respectively. Here a scenario indicates an instantiation of the tuples in r
and s.
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