Book Image

Oracle Database 11gR2 Performance Tuning Cookbook

By : Ciro Fiorillo
Book Image

Oracle Database 11gR2 Performance Tuning Cookbook

By: Ciro Fiorillo

Overview of this book

Oracle's Database offers great performance, scalability, and many features for DBAs and developers. Due to a wide choice of technologies, successful applications are good candidates to run into performance issues and when a problem arises it's very difficult to identify the cause and the right solution to the problem. The Oracle Database 11g R2 Performance Tuning Cookbook helps DBAs and developers to understand every aspect of Oracle Database that can affect performance. You will be guided through implementing the correct solution in a proactive way before problems arise, and how to diagnose issues on your Oracle database-based solutions. This fast-paced book offers solutions starting from application design and development, through the implementation of well-performing applications, to the details of deployment and delivering best-performance databases. With this book you will quickly learn to apply the right methodology to tune the performance of an Oracle Database, and to optimize application design and SQL and PL/SQL code. By following the real-world examples you will see how to store your data in correct structures and access and manipulate them at a lightning speed. You will learn to speed up sort operations, hack the optimizer and the data loading process, and diagnose and tune memory, I/O, and contention issues. The purpose of this cookbook is to provide concise recipes, which will help you to build and maintain a very high-speed Oracle Database environment.
Table of Contents (21 chapters)
Oracle Database 11gR2 Performance Tuning Cookbook
Credits
About the Author
Acknowledgement
About the Reviewers
www.PacktPub.com
Preface
Index

Inspecting indexes and triggers overhead


In this recipe we will see the overhead introduced by indexes and triggers on DML operations. We will explore alternative ways to implement calculated fields using virtual columns instead of triggers.

How to do it...

The following steps will demonstrate the index and trigger overheads:

  1. Connect to the SH schema:

    CONNECT sh@TESTDB/sh
    
  2. Create an empty table MY_CUSTOMERS, copying the CUSTOMERS table structure:

    CREATE TABLE MY_CUSTOMERS AS
      SELECT * FROM CUSTOMERS WHERE ROWNUM < 1;
    
  3. nsert all of the records from CUSTOMERS to MY_CUSTOMERS, measuring time:

    SET TIMING ON
    INSERT INTO MY_CUSTOMERS SELECT * FROM CUSTOMERS;
    SET TIMING OFF
    
  4. Truncate the MY_CUSTOMERS table:

    TRUNCATE TABLE MY_CUSTOMERS;
    
  5. Add a unique index and three B-tree indexes on the MY_CUSTOMERS table:

    CREATE UNIQUE INDEX IX1_MY_CUSTOMERS
     ON MY_CUSTOMERS (CUST_ID);
    CREATE INDEX IX2_MY_CUSTOMERS
     ON MY_CUSTOMERS (CUST_LAST_NAME, CUST_FIRST_NAME);
    CREATE INDEX IX3_MY_CUSTOMERS
     ON MY_CUSTOMERS...