Determine the Upgrade Path

Determine the Upgrade Path

The path that you must take to upgrade to Oracle Database 11g Release 1 (11.1) depends on the release number of your current database. It might not be possible to upgrade directly from your current version of Oracle Database to the latest version. Depending on your current release, you might be required to upgrade through one or more intermediate releases to upgrade to Oracle Database 11g Release 1 (11.1).

For example, if the current database is running release 8.1.6, then follow these steps:

1.     Upgrade release 8.1.6 to release 8.1.7.4 using the instructions in Oracle8i Migration Release 3 (8.1.7).

2.     Upgrade release 8.1.7.4 to 10.2.0 using the instructions in Oracle Database Upgrade Guide 11g Release 2 (10.2).

3.     Upgrade release 10.2.0 to Oracle Database 11g Release 1 (11.1) using the instructions in this guide.

·        7.3.3 (or lower)      à 7.3.4     à 9.2.0.8   à 11.1

·        8.0.5 (or lower)      à 8.0.6     à 9.2.0.8   à 11.1

·        8.1.7 (or lower)      à 8.1.7.4   à 10.2.0   à 11.1

·        9.0.1.3 (or lower)   à 9.0.1.4   à 10.2.0   à 11.1

·        10.2.0.4 (or lower) à 10.2.0.5 à 11.2.0.1/11.2.0.3

Overview of the Database Upgrade Process

Overview of the major steps required to upgrade an existing Oracle database to Oracle Database 11g Release 1 (11.1). Oracle Database 11g Release 1 (11.1) is compatible with all earlier Oracle Database releases.

Oracle Database 11g Release 1 (11.1) supports the following tools and methods for upgrading a database to the new release:

·        Database Upgrade Assistant (DBUA)

Provides a graphical user interface (GUI) that guides you through the upgrade of a database. DBUA can be launched during installation with the Oracle Universal Installer, or you can launch DBUA as a standalone tool at any time in the future.

Note: DBUA is the recommended method for performing a major release upgrade or patch release upgrade.

·        Manual upgrade using SQL scripts and utilities

Provides a command-line upgrade of a database, using SQL scripts and utilities.

·        Export and Import utilities

Uses the Oracle Data Pump Export and Import utilities, available as of Oracle Database 10g Release 1 (10.1), or the original Export and Import utilities, to perform a full or partial export from your database, followed by a full or partial import into a new Oracle Database 11g Release 1 (11.1) database. Export/Import can copy a subset of the data, leaving the database unchanged.

·        CREATE TABLE AS SQL statement

Copies data from a database into a new Oracle Database 11g Release 1 (11.1) database. Data copying can copy a subset of the data, leaving the database unchanged.

Choose an Upgrade Method

The following sections describe the upgrade methods you can use to upgrade your database to Oracle Database 11g Release 1 (11.1):

·        Database Upgrade Assistant

·        Manual Upgrade

·        Export/Import

1. Database Upgrade Assistant

Database Upgrade Assistant (DBUA) interactively steps you through the upgrade process and configures the database for Oracle Database 11g Release 1 (11.1). DBUA automates the upgrade process by performing all of the tasks normally performed manually. DBUA makes appropriate recommendations for configuration options such as tablespaces and redo logs. You can then act on these recommendations.
DBUA provides support for Oracle Real Application Clusters (Oracle RAC) and Automatic Storage Management (ASM).

2. Manual Upgrade

A manual upgrade consists of running SQL scripts and utilities from a command line to upgrade a database to Oracle Database 11g Release 1 (11.1).
While a manual upgrade gives you finer control over the upgrade process, it is more susceptible to error if any of the upgrade or pre-upgrade steps are either not followed or are performed out of order.

Before the Upgrade

When manually upgrading a database, perform the following pre-upgrade steps:

• Analyze the database using the Pre-Upgrade Information Tool. The Pre-Upgrade Information Tool is a SQL script that ships with Oracle Database 11g Release 1 (11.1), and must be run in the environment of the database being upgraded.
• The Pre-Upgrade Information Tool displays warnings about possible upgrade issues with the database. It also displays information about required initialization parameters for Oracle Database 11g Release 1 (11.1).
• Prepare the new Oracle home.
• Perform a backup of the database.

Depending on the release of the database being upgraded, you might be required to perform additional pre-upgrade steps (adjust the parameter file for the upgrade, remove obsolete initialization parameters and adjust initialization parameters that might cause upgrade problems).

After the Upgrade

Review the upgrade spool log file and use the Post-Upgrade Status Tool. The Post-Upgrade Status Tool is a SQL script that ships with Oracle Database 11g Release 1 (11.1), and should be run in the environment of the new release.

3. Export/Import

Unlike DBUA or a manual upgrade, the Export/Import utilities physically copy data from your current database to a new database. You can use either the Oracle Data Pump Export and Import utilities, available as of Oracle Database 10g Release 1 (10.1), or the original Export and Import utilities, to perform a full or partial export from your database, followed by a full or partial import into a new Oracle Database 11g Release 1 (11.1) database. Export/Import can copy a subset of the data in a database, leaving the original database unchanged.
When upgrading from Oracle Database 10g Release 1 (10.1) or higher, Data Pump Export and Import are recommended for higher performance.
The Export utility of the current database copies specified parts of the database into an export dump file. Then, the Import utility of Oracle Database 11g Release 1 (11.1) loads the exported data into a new database. However, the new Oracle Database 11g Release 1 (11.1) database must already exist before it can be loaded from the export dump file.
When importing data from an earlier release, the Oracle Database 11g Release 1 (11.1) Import utility makes appropriate changes to data definitions as it reads export dump files from earlier releases.
The following sections highlight aspects of Export/Import that might help you to decide whether to use Export/Import to upgrade your database.

Export/Import Effects on Upgraded Databases

The Export/Import upgrade method does not change the current database, which enables the database to remain available throughout the upgrade process. However, if a consistent snapshot of the database is required (for data integrity or other purposes), then the database must run in restricted mode or must otherwise be protected from changes during the export procedure. Because the current database can remain available, you can, for example, keep an existing production database running while the new Oracle Database 11g Release 1 (11.1) database is being built at the same time by Export/Import. During the upgrade, to maintain complete database consistency, changes to the data in the database cannot be permitted without the same changes to the data in the new Oracle Database 11g Release 1 (11.1) database.
Most importantly, the Export/Import operation results in a completely new database. Although the current database ultimately contains a copy of the specified data, the upgraded database might perform differently from the original database. For example, although Export/Import creates an identical copy of the database, other factors, such as disk placement of data and unset tuning parameters, might cause unexpected performance problems.

Export/Import Benefits

Upgrading using Export/Import offers the following benefits:

·        Defragments the data - you can compress the imported data to improve performance.

·        Restructures the database - you can create new tablespaces or modify existing tables, tablespaces, or partitions to be populated by imported data.

·        Facilitates side-by-side testing of the old and new versions of Oracle Database because an entirely new database is created.

·        Enables the copying of specified database objects or users - you can import only the objects, users, and other items that you wish. This is useful for establishing a test environment for the new software on only a subset of the production data. Data Pump Export / Import provides very flexible data subsetting capabilities.

·        Serves as a backup archive - you can use a full database export as an archive of the current database.

·        Allows the new database to be established on an Operating System or hardware platform that is different from that supporting the database being upgraded. Network-based Data Pump Import allows the new Oracle database to be directly loaded across the network from the old database being upgraded. Thus, no intervening dump files are required.