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

Using triggers and virtual columns


In this recipe, we will see how to use virtual columns, a new feature in Oracle Database 11g, to avoid the use of DML triggers, resulting in a performance gain in our applications.

Note

Virtual columns can also be used in referential integrity, tables can be partitioned by them, and statistics can be gathered on them.

How to do it...

The following steps will demonstrate the use of virtual columns:

  1. Connect to the SH schema:

    CONNECT sh@TESTDB/sh
    
  2. Create a table and call it LOANS:

    CREATE TABLE sh.LOANS (
      LOAN_ID INT NOT NULL,
      PAYMENT NUMBER,
      NUMBER_PAYMENTS NUMBER,
      GROSS_CAPITAL NUMBER);
    
  3. Create a trigger on the LOANS table to calculate the GROSS_CAPITAL field, giving the number of payments and the amount of every single payment:

    CREATE OR REPLACE TRIGGER TR_LOANS_INS
      BEFORE UPDATE OR INSERT ON sh.LOANS
      FOR EACH ROW
    BEGIN
      :new.GROSS_CAPITAL := :new.PAYMENT * :new.NUMBER_PAYMENTS;
    END;
    /
    
  4. Insert several rows in the LOANS table and query against it, measuring...