Upgrading to Oracle Database 11g

If you have previously installed an earlier version of the Oracle database server, you can upgrade your database to Oracle Database 11g. Multiple upgrade paths are supported; the right choice for you will depend on factors such as your current Oracle software version and your database size. In this chapter, you will see descriptions of these methods along with guidelines for their use.

If you have not used a version of Oracle prior to Oracle Database 11g you can skip this chapter for now. However, you will likely need to refer to it when you upgrade from Oracle Database 11g to a later version or when you migrate data from a different database into your database.

Prior to beginning the upgrade, you should read the Oracle Database 11g Installation Guide for your operating system. A successful installation is dependent on a properly configured environment—including operating system patch levels and system parameter settings. Plan to get the installation and upgrade right the first time rather than attempting to restart a partially successful installation. Configure the system to support both the installation of the Oracle software and the creation of a usable starter database.

This chapter assumes that your installation of the Oracle Database 11g software (see Chapter 1 and the appendix titled "Installation and Configuration") completed successfully and that you have an Oracle database that uses an earlier version of the Oracle software on the same server. Note that whether you are installing from scratch or upgrading a previous version of the Oracle Database, there are distinct advantages to installing the Oracle Database 11g software and creating the database in separate steps. When installing from scratch, you have greater control over initialization parameters, database file locations, memory allocation, and so forth when you create the database in a separate step; when upgrading from a previous release, installing the software first provides you with the Oracle Pre-Upgrade Information Tool that you use against the existing database to alert you to any potential compatibility problems when you upgrade to Oracle Database 11g . To upgrade that database, you have four options:

• Use the Database Upgrade Assistant (DBUA) to guide and perform the upgrade in place. The old database will become an Oracle 11g database during this process. DBUA supports both Oracle Real Application Clusters (RAC) and Automatic Storage Management (ASM); you can launch DBUA as part of the installation process or as a standalone tool after installation. Oracle strongly recommend using DBUA for Oracle Database major releases or patch release upgrades.
• Perform a manual upgrade of the database. The old database will become an Oracle 11g database during this process. While you have very precise control over every step of the process, this method is more susceptible to error if you miss a step or forget a prerequisite step.
• Use the Export and Import (or Oracle Data Pump) utilities to move data from an earlier version of Oracle to the Oracle 11g database. Two separate databases will be used—the old database as the source for the export and the new database as the target for the import. If you are upgrading from Oracle Database 10g , you will use Oracle Data Pump to move your data from the old database to the new database.
• Copy data from an earlier version of Oracle to an Oracle 11g database. Two separate databases will be used—the old database as the source for the copy and the new database as the target for the copy. This method is the most straightforward because your migration consists primarily of create table as select SQL statements referencing the old and newdatabases; however, unless your database has very few tables and you aren't concerned with using existing SQL tuning sets, statistics, and so forth, Oracle does not recommend this method for production databases.

  Upgrading a database in place—via either the Database Upgrade Assistant or the manual upgrade path—is called a direct upgrade. Because a direct upgrade does not involve creating a second database for the one being upgraded, it may complete faster and require less disk space than an indirect upgrade.

• NOTE Direct upgrade of the database to version 11 is only supported if your present database is using one of these releases of Oracle: 9.2.0.4, 10.1.0.2, or 10.2.0.1. If you are using any other release, you will first have to upgrade the database to one of those releases or you will need to use a different upgrade option. Oracle 8.0.6 is only supported for some versions (generally 64-bit), so be sure to check the online certification matrixes at Oracle's Metalink site or in the Oracle Database Upgrade Guide.
• NOTE Plan your upgrades carefully; you may need to allow time for multiple incremental upgrades (such as from 8.1.7 to 8.1.7.4 to 9.2.0.8) prior to upgrading to Oracle Database 11g .

Continue reading this chapter by downloading a free .pdf of Upgrading to Oracle Database 11g from the Oracle Database 11g DBA Handbook .

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