Extended SQL Trace Data

  • Cary Millsap


Way back in 1992, Oracle introduced a new means of extracting detailed response time information from a database: the extended SQL trace mechanism. In 1995, I began to learn much more about this feature when my colleagues at Oracle Corporation used it to remove the guesswork from Oracle performance improvement projects. The magic of this new extended SQL trace feature was that it allowed analysts to predict the exact response time impact of a proposed system change. At the time, this predictive ability was revolutionary. Predictability and the resulting notion of “fully informed decision making” has been the foundation of my career ever since.


Trace Data Direct Memory Access Trace File Oracle Database Buffer Cache 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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  1. Millsap, Cary. “Why you should focus on LIOs instead of PIOs” Hotsos (, 2001.
  2. Millsap, Cary, and Jeff Holt. Optimizing Oracle Performance. Sebastopol, CA: O’Reilly & Associates, 2003.Google Scholar

Copyright information

© Mogens Nørgaard, James Morle, Dave Ensor, Tim Gorman, Kyle Hailey, Anjo Kolk, Jonathan Lewis, Connor McDonald, Cary Millsap, David Ruthven, Gaja Krishna Vaidyanatha 2004

Authors and Affiliations

  • Cary Millsap

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