Improvements on a Heuristic Algorithm for Multiple-Query Optimization

Multiple query processing has received a lot of attention recently The problem arises in many areas such as extended relational database systems and deductive database systems In this paper we describe a heuristic search algorithm for this problem This algorithm uses an improved heuristic function that enables it to expand only a small fraction of the nodes expanded by an algorithm that has been proposed in the past In addition it handles implied relationships without increasing the size of the search space or the number of nodes generated in this space We include both theoretical analysis and experimental results to demonstrate the utility of the algorithm Index Terms Multiple query optimization relational databases heuristic algorithms algorithm complexity This research was partially sponsored by the National Science Foundation under Grants IRI IRI NSFD CDR to the University of Maryland Systems Research Center and IRI PYI Award by DEC and Bellcore by the Air Force O ce for Scienti c Research under Grant AFOSR and by UMIACS Also supported by a Korean Government Overseas Scholarship Also with University of Maryland Institute for Advanced Computer Studies UMIACS Also with the University of Maryland Systems Research Center SRC