Departmental Papers (CIS)

Date of this Version

May 2000

Document Type

Conference Paper


Copyright ACM, 2000. This is the author's version of the work. It is posted here by permission of ACM for your personal use. Not for redistribution. The definitive version was published in Proceedings of the 2000 ACM SIGMOD International Conference on Management of Data, pages 273-284.
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In a previous paper we proposed a novel method for generating alternative query plans that uses chasing (and back-chasing) with logical constraints. The method brings together use of indexes, use of materialized views, semantic optimization and join elimination (minimization). Each of these techniques is known separately to be beneficial to query optimization. The novelty of our approach is in allowing these techniques to interact systematically, e.g., nontrivial use of indexes and materialized views may be enabled only by semantic constraints.

We have implemented our method for a variety of schemas and queries. We examine how far we can push the method in term of complexity of both schemas and queries. We propose a technique for reducing the size of the search space by "stratifying" the sets of constraints used in the (back)chase. The experimental results demonstrate that our method is practical (i.e., feasible and worthwhile).



Date Posted: 08 May 2005