WEEKLY SEMINAR ON LOGIC AND AI

Tuesday, Oct. 17. 1995

TIME: 3:30 P.M. - 4:30 P.M.

PLACE: Room 3258 AVW Bldg. University of Maryland at College Park

SPEAKER: Jarek Gryz

Dept. of Computer Science UMCP

TITLE: ``Semantic Query Optimization for Bottom-Up Evaluation''

ABSTRACT:

Semantic query optimization uses semantic knowledge in databases (in the form of integrity constraints) to rewrite queries and logic programs for the purpose of more efficient query evaluation. Much work has been done to develop various techniques for optimization. Most of it, however, is only applicable to top-down query evaluation strategies. Moreover, little attention has been paid to the cost of the optimization itself.

In this talk, I address the issue of semantic query optimization for bottom-up query evaluation strategies with an emphasis on overall efficiency. I restrict my attention to a single optimization technique, join elimination. I discuss various factors that influence the cost of semantic optimization, and present an abstract algorithm which combines query evaluation with semantic optimization using heuristics to achieve the largest possible savings.

Everyone is welcome to attend.

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