Best Practices for Gathering Optimizer Statistics ... - Oracle

Best Practices for Gathering Optimizer Statistics with Oracle database 19c Oracle W HITE PAPER / DECEMBER 9, 2019. INTRODUCTION. The Oracle Optimizer examines all of the possible plans for a SQL statement and picks the one with the lowest cost, where cost represents the estimated resource usage for a given plan. In order for the Optimizer to accurately determine the cost for an execution plan it must have information about all of the objects (table and indexes) accessed in the SQL statement as well as information about the system on which the SQL statement will be run. This necessary information is commonly referred to as Optimizer Statistics . Understanding and managing Optimizer Statistics is key to optimal SQL execution. Knowing when and how to gather Statistics in a timely manner is critical to maintaining acceptable performance.

The Oracle database collects statistics for database objects that are missing statistics or have “stale” (out of date) statistics. This is done by an automatic task that executes during a predefined maintenance window. Oracle internally prioritizes the database objects

Loading..

Tags:

  Oracle, Database, Practices, Statistics, Optimizers, Oracle database, Gathering, Practices for gathering optimizer statistics

Information

Related search queries