Join optimization in a compiled OPS5 environment

The purpose of this thesis has been to determine the merits of incorporating a join ordering scheme for the compilation of OPS5 programs. We have constructed a compiler which uses the TREAT match algorithm and run benchmarks using three ordering schemes. Initial results based on simple hand-timings showed little advantage for ordering for most cases, but one benchmark showed dramatic improvement. Subsequent analysis has revealed that improvements to the join phase were masked by implementation problems with the compiled system. Further analysis of results concentrating solely on the join phase revealed that the ordering methods did improve the performance of the join phase by significant amounts in four of the six benchmark programs. A more detailed analysis of three benchmarks (including the two which showed no improvement) was carried out. For the benchmarks showing no improvement it was determined that these particular runs and perhaps the rule systems they pertain to are not amenable to the type of static join ordering that we have performed