Parallel Bottom-up Evaluation of Datalog Progrm~ by Load Sharing Parallel Boitom·up Evaluanon of Datalog Programs by Load Sharing

We propose a method of parallelizing bottom-up-evaluation of logic programs. The method is distinguished by the fact that it is pUTe i.e., does not require interprocessor communication, or synchronization overhead. The method cannot be used to parallelize every logic progtam, but we syntactically characterize several classes of logic programs to which the method can be applied (e.g., the class of linear single rule programs). We also provide a characterization for a class of programs to which the parallelization method cannot be applied, and show that in genera,l, determining app~i1ity is undecidable. Then, we generalize the concepts beyond the proposed method, and lay the foundations for a theory of logic progranis and p8rallelization. It demonstrates that the logic pro~s have an interesting hiezarchical classstructure, with respect to pure paraIlelization.' 1. This researclt was rupported by Technioo V. P. R. Fund • Elron-Elbit Electronic rese.arclt fund. T ec hn io n C om pu te r Sc ie nc e D ep ar tm en t T eh ni ca l R ep or t C S0 56 4 19 89