Super-TC: an efficient generic algorithm for processing the instantiated transitive-closure queries in deductive database systems

A generic algorithm is presented, suitable for processing an important class of recursive queries, the so-called instantiated transitive-closure (TC) queries. The most important characteristics of this algorithm is that it reads any data-page from the system´s disk at most once, i.e., the worst-case I/O behavior of this algorithm is linear with respect to the number of pages storing the database. Several variants, each with a different main-memory requirement, to the super-TC algorithm as well as a comparative performance evaluation of these variants are presented. The super-TC variant with minimum main-memory requirement is determined. A comparison of this variant with the more traditional δ-wavefront algorithm reveals the superiority of the super-TC variant, which is up to seven times faster