A Characterization of the Sensitivity of Query Optimization to Storage Access Cost Parameters

Most relational query optimizers make use of information about the costs of accessing tuples and data structures on various storage devices. This information can at times be off by several orders of magnitude due to human error in configuration setup, sudden changes in load, or hardware failure. In this paper, we attempt to answer the following questions: ? Are inaccurate access cost estimates likely to cause a typical query optimizer to choose a suboptimal query plan? ? If an optimizer chooses a suboptimal plan as a result of inaccurate access cost estimates, how far from optimal is this plan likely to be? To address these issues, we provide a theoretical, vector-based framework for analyzing the costs of query plans under various storage parameter costs. We then use this geometric framework to characterize experimentally a commercial query optimizer. We develop algorithms for extracting detailed information about query plans through narrow optimizer interfaces, and we perform the ch...

• Type: Conference
• Year: 2003
• Where: SIGMOD
• Authors: Frederick Reiss, Tapas Kanungo
• Keywords: Commercial Query Optimizer, Database, SIGMOD 2003, Suboptimal Query Plan, Typical Query Optimizer