D5.3 Methods and techniques for query optimization

Short Description:

In this document we address the important aspect of scalability. We first analyze the INFOMIX architecture in order to identify the points where optimizations are applicable. We then give an overview of methods which can be employed for this task. Some of the methods are subsequently discussed in detail. In particular, we deal with equivalences of Datalog programs in full depth, we present focussing techniques for repair programs, efficient recombination of split repairs, and query plan optimizations. Also relevant in this respect are magic set optimizations, which have been dealt with in Deliverable D4.3 in detail. Yet other optimization techniques can be taken over from traditional database research with minor efforts, so we also do not go into detail for such approaches. For some of the techniques, which are analysed in detail in this deliverable, we also provide an experimental study by means of a prototype implementation, which back the theoretical results empirically.