This is an interinstitutional collaborative project between Oregon Graduate Institute of Science and Technology (OGI) and Portland State University (PSU). Query optimizers are one of the main means by which modern database systems achieve their performance advantages. Given a request for data manipulation or retrieval, an optimizer will choose an optimal plan for evaluating the request from among the manifold alternative strategies. Optimization for the basic relational model is considered a solved problem by many. However, new application areas such as knowledge discovery, on-line analytical processing, and complex multimedia objects, have kindled renewed research in optimization. Current optimizers have often proved inadequate to the needs of these new application areas. Researchers have developed optimization techniques, and several prototype optimizers, to support new applications. This research addresses engineering questions related to the use of new optimizers for new applications: which operators to use; which search strategies to employ; and which transforms to utilize. These investigations use the Columbia query optimizer framework and visualization environment developed at PSU and OGI. The project interacts closely with companies which produce database management systems and the hardware on which they run. The research results will help database optimizer implementors make better choices in the design of their systems, leading to better performance and more expressive query languages for commercial database systems.
