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  • [bbk2228] 第41集 Chapter 11SQL Statement Tuning(00)

    Objectives

    After completing this lesson,you should be able to do the following:

    • Control optimizer options
    • Use optimizer hints
    • Employe plan stability
    • Use store outlines(在10g,11g已经过时)
    • Use SQL Trace and TKPROF

    Overview

    The purpose of this lesson is:

    • To provide mthods to determine the resources used by SQL statements:
      • -Oracle Enterprise Manager
      • -Statuspack
      • -Explain plan
      • -SQL Trace and TKPROF
      • -Autotrace
    • To determine which SQL statements possibly require tuning
    • Not to tune the actual SQL statements

    Optimizer Modes

    There are two types of optimizer modes:

    • Rule-based:(Rule based Optimizer 俗称RBO)
      • Uses a ranking system
      • Syntax-and data dictionary-driven(基于语法逻辑和一些数据字典信息进行驱动的优化)
    • Cost-based:(Cost based Optimizer 俗称CBO)
      • Chooses the path with lowest cost
      • Statistics-driven(基于分析统计报表数据,进行优化驱动)

    备注:目前RBO已经退出历史舞台,不在实际应用中使用;

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  • 原文地址:https://www.cnblogs.com/arcer/p/3059267.html
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