摘要：
Hint帮助Optimizer得到最优的查询结果.Using Hints in SQLSELECT * FORM employees;SELECT /*+ First_rows */ FROM employees;Optimizer Plan StabilityUsers can stabilize execution plans,to force applications to use a desired SQL access path.A consistent execution path is thereby maintained through database changes.Thi 阅读全文
摘要：
Understanding OptimizerThe query optimizer performs the following steps:The optimizer generates a set fo potential plans for the SQL statement based on available access paths and hints.The optimizer estimates the cost of each plan based o statistics in the daa dictionary for the data distribution an 阅读全文
摘要：
ObjectivesAfter completing this lesson,you should be able to do the following:Control optimizer optionsUse optimizer hintsEmploye plan stabilityUse store outlines(在10g,11g已经过时)Use SQL Trace and TKPROFOverviewThe purpose of this lesson is:To provide mthods to determine the resources used by SQL state 阅读全文