Exact and inexact methods for solving the problem of view selection for aggregate queries

We present a study of the following warehouse view-selection problem: Given a frequency distribution on parameterized aggregate queries on a data warehouse, return definitions of aggregate views that, when materialized in the warehouse, would minimize the evaluation costs of the frequent queries, subject to a storage limit constraint. Optimizing the layout of stored data using view selection has a direct impact on the performance of data warehouses. However, the optimization problem is intractable, even under natural restrictions on the types of queries of interest. We introduce an integerprogramming model to obtain optimal solutions for the warehouse view-selection problem, and propose a heuristic to obtain competitive inexact solutions where our exact method is inapplicable. We show that both our approaches can be used to solve realistic-size instances of the problem. In addition, we experimentally compare our methods to those of Harinarayan et al. (1996) and Shukla et al. (1998), and delineate applicability areas for these and our approaches.