1 Introduction

Overview of the Database Upgrade Process

This section includes an overview of the major steps required to upgrade an existing Oracle Database to the new Oracle Database 10g release. These procedures transform an existing Oracle Database system (including associated applications) into an Oracle Database 10g system. Oracle Database 10g is compatible with all earlier Oracle Database releases. Therefore, databases upgraded using the procedures described in this book can work in the same manner as in earlier releases and, optionally, can leverage new Oracle Database 10g functionality.

Careful planning and use of Oracle Database 10g tools can ease the process of upgrading a database to the new Oracle Database 10g release. Oracle Database 10g supports the following methods for upgrading a database:

• Use the Database Upgrade Assistant (DBUA).

  The Database Upgrade Assistant can be launched by the Oracle Universal Installer, depending upon the type of installation that you select, and provides a graphical user interface (GUI) that guides you through the upgrade of a database. During installation, you can choose to not use the Database Upgrade Assistant, instead choosing to launch it as a standalone tool at any time in the future to upgrade a database.

  
  

  Note: The Database Upgrade Assistant is the preferred method of upgrading a database; Oracle highly recommends using the Database Upgrade Assistant to upgrade to the new Oracle Database 10g release.

  
  

• Perform a manual upgrade

  A manual upgrade provides a command line upgrade of a database, using SQL scripts and utilities.

• Perform a full or partial export from your database, followed by a full or partial import into a new Oracle Database 10g database.

  Export/Import can copy a subset of the data in a database. Export/Import leaves the database unchanged, and makes a copy of the data.

• Copy data from a database into a new Oracle Database 10g database using the SQL*Plus COPY command or the AS clause of the CREATE TABLE SQL statement.

  Data copying can copy a subset of the data in a database. Data copying leaves the database unchanged, and makes a copy of the data.

Before you upgrade a database using any of these methods, you should understand the major steps in the upgrade process. These steps are illustrated in Figure 1-1.

The following sections contain a brief outline of the major steps in the upgrade process. For detailed instructions, refer to the appropriate chapters later in this book.

Step 1: Prepare to Upgrade

• Become familiar with the features of the new Oracle Database 10g release.

• Determine the upgrade path to the new Oracle Database 10g release.

• Choose an upgrade method.

• Choose an Oracle home directory for the new Oracle Database 10g release.

• Prepare a backup strategy.

• Develop a testing plan.

Step 2: Test the Upgrade Process

• Perform a test upgrade using a test database. The test upgrade should be conducted in an environment created for testing and should not interfere with the actual production database.

Step 3: Test the Upgraded Test Database

• Perform the tests you planned in Step 1 on the test database and on the test database that was upgraded to the new Oracle Database 10g release.

• Compare results, noting anomalies between test results on the test database and on the upgraded database.

• Investigate ways to correct any anomalies you find and then implement the corrections.

• Repeat Step 1, Step 2, and the first parts of Step 3, as necessary, until the test upgrade is completely successful and works with any required applications.

Chapter 2, " Preparing to Upgrade" provides detailed information about Steps 1 through 3.

Step 4: Prepare and Preserve the Production Database

• Prepare the current production database as appropriate to ensure that the upgrade to the new Oracle Database 10g release will be successful.

• Schedule the downtime required for backing up and upgrading the production database.

• Perform a full backup of the current production database.

Step 5: Upgrade the Production Database

• Upgrade the production database to the new Oracle Database 10g release.

• After the upgrade, perform a full backup of the production database and perform other post-upgrade tasks.

Chapter 3 describes Steps 4 and 5 when using the Database Upgrade Assistant or when performing a manual upgrade. Chapter 4 describes the backup procedure after the upgrade and other post-upgrade tasks.

Step 6: Tune and Adjust the New Production Database

• Tune the new Oracle Database production database. The new Oracle Database production database should perform as good as, or better than, the database prior to the upgrade. Chapter 4 describes these tuning adjustments.

• Determine which features of the new Oracle Database 10g release you want to use and update your applications accordingly.

• Develop new database administration procedures as needed.

• Do not upgrade production users to the new Oracle Database until all applications have been tested and operate properly. Chapter 6 describes considerations for updating applications.

During the upgrade, multi-versioning can be a useful feature because you can keep multiple copies of the same database on one computer. You can use the existing release as your production environment while you test the new release.

Oracle Release Numbers

This book describes moving between different releases of the Oracle database server. Figure 1-2 describes what each part of a release number represents.

When a statement is made in this book about a major database release number, the statement applies to all releases within that major database release. References to Oracle Database include release 10.1; references to Oracle9i include release 9.0.1 and release 9.2.

Similarly, when a statement is made in this book about a maintenance release, the statement applies to all component-specific and platform-specific releases within that maintenance release. So, a statement about release 9.2 applies to release 9.2.0.1, release 9.2.0.2, and all other platform-specific releases within release 9.2.

Using Optimal Flexible Architecture (OFA)

Oracle recommends the Optimal Flexible Architecture (OFA) standard for your Oracle Database installations. The OFA standard is a set of configuration guidelines for efficient and reliable Oracle databases that require little maintenance.

OFA provides the following benefits:

• Organizes large amounts of complicated software and data on disk to avoid device bottlenecks and poor performance

• Facilitates routine administrative tasks, such as software and data backup functions, which are often vulnerable to data corruption

• Alleviates switching among multiple Oracle databases

• Adequately manages and administers database growth

• Helps to eliminate fragmentation of free space in the data dictionary, isolates other fragmentation, and minimizes resource contention.

If you are not currently using the OFA standard, then switching to the OFA standard involves modifying your directory structure and relocating your database files.

Changing Word Size

You can implicitly change the word size of your database during an upgrade or downgrade. A change in word size includes the following scenarios:

• You have 32-bit Oracle software installed on 64-bit hardware and want to change to 64-bit Oracle software.

• You have 64-bit Oracle software installed on 64-bit hardware and want to change to 32-bit Oracle software.

If you are changing word size during an upgrade or downgrade, then no additional action is required. The word size is changed automatically during either of these operations. However, if you want to explicitly change the word size within the same release, then follow the instructions in "Changing the Word Size of Your Current Release". For example, if you have the 32-bit installation of release 10.1 and you want to switch to the 64-bit installation of release 10.1, then you must complete this procedure.

The following information applies if you are switching from 32-bit hardware to 64-bit hardware or from 64-bit hardware to 32-bit hardware:

• You can switch from 32-bit hardware to 64-bit hardware and still use your existing 32-bit Oracle software without encountering any problems.

• If you want to switch from 64-bit hardware to 32-bit hardware, then you must first install 32-bit Oracle software before switching from 64-bit hardware to 32-bit hardware.

The on-disk format for database data, redo, and undo is identical for the 32-bit and 64-bit installations of Oracle. The only internal structural differences between the 32-bit and 64-bit installations are the following:

• The compiled format of PL/SQL is different. The instructions for how and when to recompile PL/SQL are provided in the appropriate chapters of this book.

• The storage format of user-defined types is based on the release of Oracle that created the database. The existing storage format will be transparently converted to the correct format when necessary. User-defined types include object types, REFs, varrays, and nested tables.

Rolling Upgrades

The term rolling upgrade refers to upgrading different databases or different instances of the same database (in a Real Application Clusters environment) one at a time, without stopping the database.

Deinstalling Options

If you want to deinstall old options when you upgrade to the new Oracle Database release, then use the Oracle Universal Installer to deinstall them. You can deinstall them before or after you upgrade, but you must use the release of the installer that corresponds with the items you want to remove.

For example, if you are running release 9.0.1 with Oracle Text installed, and you decide that you do not need this option when you upgrade to the new Oracle Database release, then you should deinstall Oracle Text in one of the following ways:

• Before you upgrade to the new Oracle Database release, use the release 9.0.1 Oracle Universal Installer to deinstall Oracle Text. Then, do not install Oracle Text when you install the new Oracle Database release.

• When you upgrade to the new Oracle Database release, install and upgrade Oracle Text. Then, use the Oracle Universal Installer in the new Oracle Database release to deinstall Oracle Text.