Following are different upgrade methods one can use to upgrade the database to the new Oracle Database 9i release or higher:
1) Database Upgrade Assistant (DBUA)
2) Manual Upgrade
3) Export/Import
4) Data Copying
5) Golden Gate
1) DBUA (Database Upgrade Assistant)
The Database Upgrade Assistant (DBUA) interactively steps you through the upgrade process and configures the database for the new Oracle Database release. The DBUA automates the upgrade process by performing all of the tasks normally performed manually. The DBUA makes appropriate recommendations for configuration options such as tablespaces and redo logs. You can then act on these recommendations. This method is very easy and user friendly. But if any error occurs it will take time to diagnose the error as the upgrade process is done automatically by the upgrade assistant. DBUA can be used only if the source & target Oracle homes are on the same Server.
Please refer to oracle documentation for complete checklist and detailed steps for upgrading using this method.
2) Manual upgrade
A manual upgrade consists of running SQL scripts and utilities from a command line to upgrade a database to the new Oracle Database release. A manual upgrade gives you finer control over the upgrade process as it is done step by step manually. So if any error occurs, it is easier to diagnose the error. 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 if they are not performed in correct sequence.
When manually upgrading a database, perform the following pre-upgrade steps:
- Analyze the database using the Pre-Upgrade Information Tool. The Upgrade Information Tool is a SQL script that ships with the new Oracle Database release, and must be run in the environment of the database being upgraded.
The Upgrade Information Tool displays warnings about possible upgrade issues with the database. It also displays information about required initialization parameters for the new Oracle Database release. - Prepare the new Oracle Home.
- Perform a backup of the database. Verify the backup if necessary.
Depending on the release of the database being upgraded, you may need 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).
Manual upgrade will work even if the source and target Home are on different servers provided that the Hardware architecture and operating system on source and target Home are the same.
Example :
– You cannot manually upgrade a database from an HP-UX Operating System to Solaris Operating System.
– You cannot manually upgrade a database from a Linux Machine to Solaris SPARC 64-bit.
Please refer to oracle documentation for complete checklist and detailed steps for upgrading using this method.
3) Export/Import
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 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.
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 may 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, may cause unexpected performance problems.
Upgrading an entire database by using Export/Import can take a long time, especially compared to using the DBUA or performing a manual upgrade. Therefore, you may need to schedule the upgrade during non-peak hours or make sure that the new database has all the changes that are made to the current database during the upgrade. Export/Import works for all versions.
For 10g and above, DataPump or Transportable Table Spaces methods are better.
Please refer to oracle documentation for complete checklist and detailed steps for upgrading using this method.
4) Data Copying
You can copy data from one Oracle Database to another using database links. For example, you can create new tables and fill the tables with data by using the INSERT INTO statement and the CREATE TABLE … AS statement. Copying data and Export/Import offer the same advantages for upgrading. Using either method, you can defragment data files and restructure the database by creating new tablespaces or modifying existing tables or tablespaces. In addition, you can copy only specified database objects or users.
Copying data, however, unlike Export/Import, enables the selection of specific rows of tables to be placed into the new database. Copying data is a good method for copying only part of a database table. In contrast, using Export/Import, you can copy only entire tables
Please refer to oracle documentation for complete checklist and detailed steps for upgrading using this method.
5) Golden Gate
GoldenGate is an advanced logical replication product that supports multi-master replication, hub and spoke deployment and data transformation, providing customers very flexible options to address the complete range of replication requirements. GoldenGate also supports replication between a broad range of heterogeneous hardware platforms and database management systems. GoldenGate captures primary database changes by reading redo records from disk, transforming those records into a platform independent trail file format, and transmitting the trail file to the target database. GoldenGate maintains a logical replica by converting the trail file into SQL and applying SQL to the target database. The target database is open read-write while synchronization occurs.
GoldenGate can be used in one or more of the following:
- Any cross platform migration
- Any requirement where the replica database must be open read-write while synchronizing with the primary database
- Maintenance and migrations where zero downtime using bi-directional replication is required
- Any advanced replication requirements such as: multimaster and bidirectional replication, subset replication, many to one replication, cross endian replication, and data transformations
- Application upgrades that modify back-end database objects. GoldenGate maintains availability and reduces planned downtime by replicating between old and new versions of the database (the user implements mapping between differences in database objects in old and new versions of the database
Please refer to oracle documentation for complete checklist and detailed steps for upgrading using this method.