Commercial database customers across the board list SQL performance tuning as one of the most time-consuming tasks for database administrators (DBAs). The 10g Oracle Database provides a feature called the SQL Tuning Advisor to simplify the task. The 11g release adds a new database feature, called Automatic SQL Tuning, that closes the feedback loop for the first time, fully automating the SQL tuning workflow and solving some SQL performance problems without any DBA intervention.

This paper presents Oracle Database Replay, a novel approach to testing changes to the relational database management system component of an information system (software upgrades, hardware changes etc). Database Replay makes it possible to subject a test system to a real production system workload, which helps identify all potential problems before implementing the planned changes on the production system. Any interesting workload period of a production database system can be captured with minimal overhead. The captured workload can be used to drive a test system while maintaining the concurrency and load characteristics of the real production workload. Therefore, the test results using database replay can provide very high assurance in determining the impact of changes to a production system before applying these changes. This paper presents the architecture of Database Replay as well as experimental results that demonstrate its usefulness as testing methodology.