A symmetric fragment and replicate algorithm for distributed joins

It is shown that the fragment and replicate (FR) distributed join algorithm is a special case of the symmetric fragment and replicate (SFR) algorithm, which improves the FR algorithm by reducing its communication. The SFR algorithm, like the FR algorithm, is applicable to N-way joins and nonequijoins and does tuple balancing automatically. The authors derive formulae that show how to minimize the communication in the SFR algorithm, discuss its performance on a parallel database prototype, and evaluate its practicality under various conditions. It is claimed that SFR improves the worst-case cost for a distributed join, but it will not displace specialized distributed join algorithms when the later are applicable