Efficiently approximating query optimizer plan diagrams

Given a parametrized n-dimensional SQL query template and a choice of query optimizer, a plan diagram is a color-coded pictorial enumeration of the execution plan choices of the optimizer over the query parameter space. These diagrams have proved to be a powerful metaphor for the analysis and redesign of modern optimizers, and are gaining currency in diverse industrial and academic institutions. However, their utility is adversely impacted by the impractically large computational overheads incurred when standard bruteforce exhaustive approaches are used for producing fine-grained diagrams on high-dimensional query templates. In this paper, we investigate strategies for efficiently producing close approximations to complex plan diagrams. Our techniques are customized to the features available in the optimizer's API, ranging from the generic optimizers that provide only the optimal plan for a query, to those that also support costing of sub-optimal plans and enumerating rank-ordere...

• Type: Journal
• Year: 2008
• Where: PVLDB
• Authors: Atreyee Dey, Sourjya Bhaumik, Harish D., Jayant R. Haritsa
• Keywords: Computational Overheads, Plan Diagrams, PVLDB 2008, Query Optimizer