A Dynamic Approach to Deductive Query Evaluation.
Andreas Behrend · 2000
In this paper, a dynamic approach to deductive query evaluation is presented which combines the effects of different SIP strategies used for the magic set rewriting technique. Given a query execution plan obtained by a single magic set transformation, this plan is normally not reoptimized, and the actual number of facts generated during query processing cannot be considered. But applying the magic set transformation again during a query evaluation process allows the use of a different SIP strategy which takes into account dynamic criteria as well, e.g. the number of generated answer facts or the number of accesses to relations. It will be shown that adapting query plans at runtime can reduce the overall number of generated facts and hence reach optimization effects which cannot be achieved by magic sets based on a single choice of SIP strategy. 1