Updating oracle statistics
Oracle Database automatically maintains optimizer statistics. You can maintain optimizer statistics manually using the package.
For example, you can save and restore copies of statistics.
The choice of executions plans made by the Oracle SQL optimizer is only as good as the Oracle statistics.
When a SQL statement is executed, the database must convert the query into an execution plan and choose the best way to retrieve the data.
For more information about AUTO_CREATE_STATISTICS, see ALTER DATABASE SET Options (Transact-SQL).