Optimising MA.Hashing Cost
For a given application, useful to minimise Costpmr.
Can be achieved by choosing appropriate values for di
(cv)
Heuristics:
- distribution of query types
(more bits to frequently used attributes)
- size of attribute domain
(≤ #bits to represent all values in domain)
- discriminatory power
(more bits to highly discriminating attributes)
Trade-off: making Qj more efficient makes
Qk less efficient.
This is a combinatorial optimisation problem
(solve via standard optimisation techniques e.g. simulated annealing)
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