On a model of indexability and its bounds for range queriesOn a model of indexability and its bounds for range queries Peer-Reviewed Journal Publication Δημοσίευση σε Περιοδικό με Κριτές 2015-10-162002enWe develop a theoretical framework to characterize the hardness of indexing data sets on block-access memory devices like hard disks. We define an indexing workload by a data set and a set of potential queries. For a workload we can construct an indexing scheme, which is a collection of fixed-sized subsets of the data. We identify two measures of efficiency for an indexing scheme on a workload: storage redundancy, r (how many times each item in the data set is stored), and access overhead, A (how many times more blocks than necessary does a query retrieve). For many interesting families of workloads, there exists a trade-off between storage redundancy and access overhead. Given a desired access overhead A, there is a minimum redundancy that any indexing scheme must exhibit. We prove a lower-bound theorem for deriving the minimum redundancy. By applying this theorem we show interesting upper and lower bounds and trade-offs between A and r in the case of multi-dimensional range queries and set queries.http://creativecommons.org/licenses/by/4.0/Journal of the ACM49135–55 Samoladas Vasilis Σαμολαδας Βασιλης Koutsourias Elias Miranker, Daniel P Hellerstein, Joseph, 1952- Papadimitriou, Christos H Association for Computing Machinery Information systems Data management systems Data structures Data access methods