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Proceedings of Fith International Conference on Deductive and ObjectOriented Databases (DOOD'97), December 812, 1997, Montreux, CH
 

Summary: Proceedings of Fith International Conference on Deductive and Object­Oriented
Databases (DOOD'97), December 8­12, 1997, Montreux, CH
Rule­Based Generation of Logical Query Plans with
Controlled Complexity
Karl Aberer, Dunren Che, and Klemens Böhm
GMD­IPSI, Dolivostr. 15, 64293 Darmstadt, Germany
E­mail: {aberer, che, kboehm}@darmstadt.gmd.de
Abstract
Rule­based queryoptimizersarerecognizedasparticularlyvaluableforextensibleandobject­ori-
ented database management systems by providing a high flexibility in adapting query optimization
strategiestononstandardapplicationneeds.Ontheotherhandrule­basedoptimizersareproblem-
atic with regard to run­time behavior for more complex queries as the generation of query plans
based on a declarative rule base tends to be difficult to control. In this paper we show that this is not
a fundamental problem of rule­based optimizers, but rather a question of careful design of the rule
system. We exemplify this for one fundamental optimization problem, namely join enumeration for
linearqueries.There,arule­basedoptimizationstrategycanachievethetheoreticallyoptimalcom-
plexity.Thedesignprinciplesusedtoachievethishavebeenderivedfromandareusedinthedesign
of the VODAK query optimizer developed at GMD­IPSI.
1 Introduction
There exists a broad spectrum of potential (nonstandard) applications of DBMS, which

  

Source: Aberer, Karl - Faculté Informatique et Communications, Ecole Polytechnique Fédérale de Lausanne

 

Collections: Computer Technologies and Information Sciences