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:
Two new system tables, systabstats, which maintains information on objects such as tables and rows, and sysstatistics which stores data distribution statistics.
New optimizer statistics and added functionality
update statistics command.
The optdiag utility, which simplifies the task of looking at optimizer statistics. This utility also allows you to model query performance by running queries against a test database with simulated table, index, and column statistics.
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