Configuring the Optimizer
The cost optimizer determines the most efficient execution plan for a SQL statement. The optimizer depends heavily on the statistics that you (or the database) gather. This chapter explains how to set the optimizer goal and how to control the behavior of the optimizer. You’ll learn how to enable and disable automatic statistics collection by the database and when to collect statistics manually. You’ll learn how to set preferences for statistics collection as well as how to validate new statistics before making them available to the optimizer. The chapter explains how to lock statistics, export statistics, gather system statistics, restore older versions of statistics, and how to handle missing statistics.
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