2022-present, Oracle Corporation, development and design.

2002-2021, SingingSQL: Founder and Principal. Consulted for over a dozen Fortune-500 companies, and many more smaller organizations both offering direct assistance with SQL tuning and teaching my classes in SQL Tuning and in writing high-quality SQL, at home and internationally.

1998-2002, TenFold Corporation: Director, Performance and Tuning, Senior Architect. Running a small group responsible for all performance and tuning issues in a 100-700-employee application software vendor. Architected the rules on Oracle, Sybase, Microsoft SQLServer, and DB2 to auto-generate SQL that rarely requires manual tuning. Tuned hundreds of specific application performance defects and architected root-cause enhancements to the Universal Application to prevent similar defects from recurring in future applications. Diagnosed and resolved performance problems from misconfiguration of the databases, servers, and networks at customer sites.

1989-1998, Oracle Corporation: Manager, Applications Performance and Tuning. Held various positions in Application Development and IT, all revolving around performance and tuning, at various layers, including hardware configuration, operating systems, database configuration, network optimization, application code optimization, and (especially) SQL tuning. Served as the final word on application performance issues, for a suite of applications including over 35,000 queries, with hundreds of complex queries. Resolved many high-priority performance problems originating from system-configuration problems. Identified several important enhancements, since implemented, to the Oracle RDBMS, for the optimizer, for the execution engine, and for shared-memory management. Built suites of internal shell and SQL based tools for diagnosing, prioritizing, and resolving performance problems in several layers with empirical data collection and analysis, not guesswork. Invented a patented new method to enforce uniqueness of complex keys, (USPatent #5860070), Method and apparatus of enforcing uniqueness of a key value for a row in a data table. Invented a patented (USPatent #5761654) , systematic tuning methodology for complex queries, which I have presented to over 1,500 people.

1986-1989, AT&T Bell Laboratories: Member of Technical Staff
Systems Engineer. Worked as a bridge person between business customers and the developers of a network management operations system, describing the customers’ system requirements in terms meaningful to the developers.