Optimizer Changes

ASE 11.9.2 introduced major changes in the way the server keeps statistics and optimizes queries. These changes were aimed at increasing granularity in the statistics kept by the server, improving query plans, and producing better performance. Changes introduced in 11.9.2 included:

These and other query processing changes for 11.9.2 are reviewed in the chapter Chapter 5, “Implement: Making Required Application Changes” and in the section Summary of Query Processing Changes in 11.9.2 and 12.0 that May Affect Performance in the white paper Technical Issues in ASE 11.9.x and 12.0 Upgrade.

For more detailed information on the systabstats and sysstatistics tables, see the chapter on “Using Statistics to Improve Performance” in the Performance and Tuning Guide. For information on the optdiag utility, see the Utility Guide