Joint Optimization of Cost and Coverage of Query Plans in Data Integration

Existing approaches for optimizing queries in data integration use decoupled strategies–attempting to optimize coverage and cost in two separate phases. Since sources tend to have a variety of access limitations, such phased optimization of cost and coverage can unfortunately lead to expensive planning as well as highly inefficient plans. In this paper we present techniques for joint optimization of cost and coverage of the query plans. Our algorithms search in the space of parallel query plans that support multiple sources for each subgoal conjunct. The refinement of the partial plans takes into account the potential parallelism between source calls, and the binding compatibilities between the sources included in the plan. We start by introducing and motivating our query plan representation. We then briefly review how to compute the cost and coverage of a parallel plan. Next, we provide both a System-R style query optimization algorithm as well as a greedy local search algorithm...

• Type: Conference
• Year: 2001
• Where: CIKM
• Authors: Zaiqing Nie, Subbarao Kambhampati
• Keywords: CIKM 2001, Information Management, Parallel Query Plans, Query Plan Representation, Query Plans