|Oracle9i Database Migration
Release 2 (9.2)
Part Number A96530-02
This chapter includes an overview of database migration as well as information about running multiple releases of Oracle. This chapter also provides information on changing the word size of your database during an upgrade or downgrade.
This chapter covers the following topics:
The following terms are used throughout this document:
The instructions in this document describe moving between different releases of the Oracle database server. Figure 1-1 describes what each part of a release number represents.
Oracle9i Database Administrator's Guide for more information about Oracle release numbers
Starting with release 9.2, maintenance releases of Oracle are denoted by a change to the second digit of a release number. In previous releases, the third digit indicated a particular maintenance release.
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 Oracle9i include all releases in release 9.0 and release 9.2; references to version 8 include all releases in release 8.0 and release 8.1. References to version 7 include all Oracle7 releases in release 7.0, release 7.1, release 7.2, and release 7.3.
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 9.0.1 applies to release 188.8.131.52, release 184.108.40.206.2, and all other platform specific releases within release 9.0.1.
Database migration refers to the collection of processes and procedures for converting the data in an Oracle database to reflect a particular release of the Oracle database server. Database migration includes the following:
Chapter 3, "Upgrading a Database to the New Oracle9i Release" for information about the upgrade process
Chapter 7, "Downgrading a Database Back to the Previous Oracle Release" for information about the downgrade process
Since this book documents upgrading and downgrading between different releases of Oracle, this definition of database migration is appropriate. However, other Oracle documentation may use a broader definition of the term migration; for example, in some cases, migration may describe the process of moving data from a non-Oracle database into an Oracle database.
This section includes an overview of the major steps required to upgrade an existing Oracle database to the new Oracle9i release. Oracle9i is compatible with all earlier Oracle 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 Oracle9i functionality.
Several preparatory steps are required before you upgrade your current production database. After the upgrade, you should perform several additional test steps. Other procedures enable you to add new Oracle9i functionality to existing applications.
Before you upgrade a database, you should understand the major steps in the upgrade process. These steps apply to all operating systems, with the possible exception of a few operating system-specific details identified in your operating system-specific Oracle documentation.
Careful planning and use of Oracle9i tools can ease the process of upgrading a database to the new Oracle9i release. You can use one of the following methods to upgrade a database:
The following sections contain a brief outline of the major steps shown in Figure 1-2. The purpose of these descriptions is to familiarize you with the major steps in the upgrade process. For detailed instructions, refer to the appropriate chapters in this book.
Chapter 2, "Preparing to Upgrade" provides detailed information about Steps 1 through 3.
Chapter 3 describes Steps 4 and 5 when using the Database Upgrade Assistant and when performing a manual upgrade. Chapter 8 describes Steps 4 and 5 when using the Export/Import utilities. Chapter 4 describes the backup procedure after the upgrade and other post-upgrade tasks.
Appendix E, "Database Migration and Compatibility for Replication Environments" if you are upgrading a database that has Oracle Replication installed
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.
Typically, the database administrator (DBA) is responsible for ensuring the success of the upgrade process. The DBA is usually involved in each step of the process, except for steps that involve testing applications on the upgraded database.
The specific DBA duties typically include the following:
The application developer is responsible for ensuring that applications designed for the current database work correctly with the upgraded Oracle9i database. Application developers often test applications against the upgraded Oracle9i database and decide which new features of Oracle9i should be used.
Before upgrading the production database, the DBA or application developer should install an Oracle9i test database. Then, the application developer can test and modify the applications, if necessary, until they work with their original (or enhanced Oracle9i) functionality.
The following references provide information about identifying differences in the upgraded Oracle9i database that could affect particular applications. Application developers can use these differences to guide modifications to existing applications.
Oracle9i includes features that aid in upgrading existing applications to Oracle9i, for example:
You can run different releases of Oracle on the same computer at the same time. However, each release can only access a database that is consistent with its release. For example, if you have Oracle8i and Oracle9i installed on the same computer, then the Oracle8i server can access Oracle8i databases but not Oracle9i databases, and the Oracle9i server can access Oracle9i databases but not Oracle8i databases. The following sections provide general information about running multiple releases of Oracle.
It is not possible to install release 9.2 products into an existing Oracle home. This functionality was only available for certain previous releases and has not been continued. An Oracle9i release must be installed in a new Oracle home that is separate from previous releases of Oracle. Also, you cannot have more than one release per Oracle home. Oracle Corporation recommends that you adopt an Optimal Flexible Architecture (OFA) when creating multiple Oracle homes. See "Using Optimal Flexible Architecture (OFA)" for more information.
Your operating system-specific Oracle documentation for more information about running multiple releases of Oracle on your operating system. Restrictions may apply on some operating systems.
You can install Oracle7, Oracle8, Oracle8i, and Oracle9i databases in multiple (separate) Oracle homes on the same computer and have Oracle7, Oracle8, Oracle8i, and Oracle9i clients connecting to any or all of the databases.
You can install Oracle7, Oracle8, Oracle8i, and Oracle9i databases in multiple (separate) Oracle homes on separate computers and have Oracle7, Oracle8, Oracle8i, and Oracle9i clients connecting to any or all of the databases.
You can upgrade an Oracle7, Oracle8, Oracle8i, or Oracle9i database to the current Oracle9i release and have Oracle7, Oracle8, Oracle8i, and Oracle9i clients connecting to the upgraded database. You cannot upgrade the database in the same Oracle home.
You can upgrade any or all of your Oracle7, Oracle8, Oracle8i, or Oracle9i clients to the current Oracle9i release. You can also upgrade your Oracle7, Oracle8, Oracle8i, or Oracle9i database to the current Oracle9i release at a later date.
Oracle Corporation recommends the Optimal Flexible Architecture (OFA) standard for your Oracle9i 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:
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.
You can implicitly change the word size of your database during an upgrade or downgrade. A change in word size includes the following scenarios:
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 9.2 and you want to switch to the 64-bit installation of release 9.2, 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:
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 term rolling upgrade refers to upgrading different databases or different instances of the same database in Oracle9i Real Application Clusters one at a time, without stopping the database. Oracle9i Real Application Clusters does not support rolling upgrades.
If you want to deinstall old options when you upgrade to the new Oracle9i 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 Oracle9i release, then you should deinstall Oracle Text in one of the following ways: