Dynamic query optimization in Rdb/VMS

摘要

Addresses the key theoretical and practical issues of dynamic query optimization and reviews the underlying reasoning that cements the basic concepts of dynamic query optimization. The optimization mechanics are described, in concert with explanations of why and how certain arrangements contribute to a given optimization goal. Compared to traditional approaches, dynamic query optimization offers a much more realistic view of cost distribution modeling. It is a competition-based architecture that is capable of resolving the major limitations of static optimization, viz. the problems of data skew, cost function instability, and host-variable sensitivity.