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Upgrading to Oracle Database 12c

Author: Chad Cleveland | | July 21, 2016

Database upgrade refers to modification of data dictionary for compatibility with a newer Oracle database version. Oracle Database 12c, which is the latest version, has incorporated new robust features like Oracle Active Data Guard Far Sync, Oracle Multitenant option, new data types, and many others.

Upgrading to Oracle Database 12c brings more benefits to your organization, including enhanced security, improved performance and expanded functionality. Oracle Database 12c is the current epitome of modern IT infrastructure with improvement of operational efficiency for cost reduction and increased productivity.

There are various ways of upgrading to Oracle Database 12c. The best method would ideally offer the fastest upgrade with minimum possible downtime, depending on your source database release version and source and destination of operating systems.

This blog post explains methods of upgrading directly to Oracle Database 12c and the factors to consider before selecting a specific method.

There are two main methods of upgrading directly to Oracle Database 12c.

  • Database Upgrade Assistant (DBUA)
  • Command-line upgrade script

These two methods are the fastest and easiest ways to upgrade an existing database to 12c. Also, the upgrade occurs without creating a copy of the existing database, that’s why it’s referred to as “in-place upgrade”.

To use either of the two methods, the minimum version of your source database should For versions lower than this, database upgrade can be accomplished via any of the following methods:

  • Transportable Tablespaces (TTS)
  • Oracle Data Pump Export/Import
  • Original Export/Import Utilities

Database Upgrade Assistant (DBUA)

DBUA is a GUI that leads you all through the whole database upgrade process presenting a variety of options. It also performs pre-upgrade validation steps and automates post-upgrade tasks. DBUA offers the advantage of reducing the manual effort for database upgrade. For more details on how to use DBUA, check out the Oracle Guide.

Factors to consider before using DBUA method

  • DBUA can only be used if you are upgrading the database on its current hardware server. If you want to upgrade while migrating to a new hardware server, you’ll have to install both the old and new database versions on that new server.
  • DBUA cannot be restarted once the upgrade process has started. In case you stop the upgrade process and not restore the database, you can continue only via the command-line upgrade script.

Command-line upgrade script

Command-line upgrade utility ( is a new feature in 12c and has replaced catupgrd.sql script used in the previous versions. This new feature utilizes parallel processing in the database upgrade, hence the reduced database upgrade downtime and a much more improved database upgrade performance.

This method is usually implemented when migrating database to new hardware server with database upgrade and in situations where DBAs require more control in the database upgrade. This database upgrade process takes the same amount of time as with the DBUA.

The pre-upgrade information tool (preupgrd.sql) automatically generates fixup scripts to resolve any issues that may halt the upgrade process. Also, the post-upgrade is enhanced and automated in order to run all the post-upgrade steps. For more details on how to use command-line upgrade script, please see the Oracle Guide.

Factors to consider before using Command-line Upgrade Script method

  • This method is recommended for DBAs with a personal preference to have more control by typing commands in the command line.
  • This utility is suitable when migrating database to new hardware server with database upgrade
  • You can restart the database upgrade process easily when using this method.

If you need help upgrading to Oracle Database 12c, or to learn more, contact Datavail today. With more than 600 database administrators worldwide, Datavail is the largest database services provider in North America. With 24×7 managed database services, including database design, architecture and staffing, Datavail can support your organization as it works with MySQL, regardless of the build you ultimately select.

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