  With the more and more growing demand for semantic Web services over large
databases, an efficient evaluation of Datalog queries is arousing a renewed
interest among researchers and industry experts. In this scenario, to reduce
memory consumption and possibly optimize execution times, the paper proposes
novel techniques to determine an optimal indexing schema for the underlying
database together with suitable body-orderings for the Datalog rules. The new
approach is compared with the standard execution plans implemented in DLV over
widely used ontological benchmarks. The results confirm that the memory usage
can be significantly reduced without paying any cost in efficiency. This paper
is under consideration in Theory and Practice of Logic Programming (TPLP).
