A method, apparatus, and article of manufacture for executing a database query in a database management system. The method comprises the steps of generating a plurality of query plans for the database query, evaluating the plurality of query plans using a measured value for the resource metric, selecting...http://www.google.de/patents/US6353818?utm_source=gb-gplus-sharePatent US6353818 - Plan-per-tuple optimizing of database queries with user-defined functions
