Pattern match reduction for Relational Production Language in the USL MMDBS
Lois Delcambre, J. Waramahaputi, James N. Etheredge · ACM SIGMOD Record · 1989
The Relational Production Language, RPL, is a rule language where both the condition and action part of a rule is expressed in a relational language. This makes RPL a natural choice for expert database systems. In this paper, the performance of the RPL interpreter is addressed through the use of Pattern Match Reduction, PMR, within the context of the USL main memory database system, the USL MMDBS. PMR provides a generalization of relational view materialization by supporting relationally complete queries and by allowing the materialization of any/all intermediate nodes in a query tree. The USL MMDBS supports PMR because of its performance characteristics for query processing (due to a linear sort/join algorithm) and because intermediate query results are stored as “first class” relations. Thus the materialization required by PMR is directly supported. This paper introduces PMR and the USL MMDBS and presents preliminary performance results.