Other comments on 'Optimization algorithms for distributed queries' by P.M.G. Apears

Abstract

An erroneous fact concerning the assumption of irreducibility of nonjoining attributes of the distributed query optimization algorithm called GENERAL presented in the above paper (see ibid., vol.SE-9, no.1, p.57-68, Jan. 1983) is pointed out. It is shown that it is possible to generate an efficient semijoin program with better response time than the one produced by the GENERAL algorithm. A counterexample that proves this possibility is provided.< >