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DBUA : Understanding New Changes / Features


Oracle Database – Enterprise Edition – Version and later
Information in this document applies to any platform.


This article helps to understand the new changes / features incorporated with the new 12c Release 2 (12.2) DBUA


12.2 DBUA new features availability


The 12.2 Database Upgrade Assistant includes numerous new features and code enhancements.

Database Upgrade Assistant (DBUA) provides a graphical user interface 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.

Pre-upgrade script with DBUA

Database Upgrade Assistant (DBUA) and the Pre-Upgrade Information Tool perform detailed checks of the database that you want to upgrade, and the special scripts are generated specifically to fix any problems that are found.

During the pre-upgrade phase, you can interactively run fixup scripts to resolve issues that are found. Post-upgrade fixup scripts are generated depending on the results of the upgrade process. DBUA prompts you to run the appropriate scripts as critical issues are found.

DBUA starts the Pre-Upgrade Tool, which automatically fixes some configuration settings to the values required for the upgrade. For example, the Pre-Upgrade Tool can change initialization parameters to values required for the upgrade. The Pre-Upgrade Tool also provides you with a list of items that you need to fix manually before you can continue with the upgrade.

DBUA and Parallel Upgrade Utility

Database Upgrade Assistant (DBUA) takes full advantage of the Parallel Upgrade Utility. DBUA runs in parallel upgrade mode by default by using perl script. Parallel processing decreases the time for the database upgrade by optimizing the use of CPU power in the system where the database is located.

DBUA Can Be Restarted During the Upgrade Process:

In 12.2 release, there are more options for recovering from failures during upgrade and for restarting the upgrade from the point where the failure occurred.

Enhanced Pre-Upgrade and Post-Upgrade Summary Report

DBUA generates HTML reports before and after the upgrade. The reports DBUA generates include component status. The reports also enable you to check details of database object status, including invalid objects, where an action to fix a problem may be available.

Oracle XML Database is Installed When You Upgrade

You cannot uninstall Oracle XML DB, and there is no option not to include it when you create a new database. During the upgrade, if Oracle XML DB is not found, then Oracle XML DB is automatically loaded into the SYSAUX tablespace. The upgraded Oracle Database includes Oracle XML DB.


  • Below screenshots demonstrate the new changes introduced with Oracle DBUA. New 12.2 DBUA list out all the databases and facilitates with the database filter option.
    In the two panels, the left panel shows all the steps executed by DBUA and the right panel shows the progress of all operations listed in the left panel. As per the below screen, DBUA will list out the databases from the respective Source Oracle Homes from /etc/oratab file.

list out the database from oratab file

  • Once you choose the SID/database and click Next, DBUA will list out the pluggable databases under container database of source Oracle Home. The 12.2 DBUA provides a new feature where we can prioritize the upgrade of the pluggable databsaes within the container. We can set the priority for PDBs, so that higher priority PDBs are upgraded first.

prioritize PDBs


  • After setting priority, DBUA will run the pre-upgrade tool against the database. The Pre-Upgrade Information Tool is now delivered as a single .jar file for easier porting, copying, and migrating of the tool between systems. The Pre-Upgrade Information Tool (preupgrade.jar) carries out system checks, and generates fixup scripts.DBUA analyzes the databases, performing pre-upgrade checks and displaying warnings as necessary. Examples of DBUA checks and actions DBUA performs on the database include:
    • Empty database recycle bin.
    • Identify invalid objects.
    • Identify deprecated and desupported initialization parameters.
    • Identify time zone data file version.

    The analysis takes several minutes to complete. When DBUA finishes its analysis, the Prerequisite Checks window displays. When you have fixed detected errors, click “Fix and Check Again” Next.



  • This window provides the following options:

Enable Parallel Upgrade: Select this option to enable parallelism during the upgrade process. Running upgrade processes in parallel reduces the time needed to perform the upgrade, based on the number  of CPUs available to handle the running of scripts and processes simultaneously.

Recompile Invalid Objects During Post Upgrade: Select this option to recompile all invalid PL/SQL modules after the upgrade is complete. If you do not have DBUA recompile invalid objects in its  post-upgrade phase, then you must manually recompile invalid objects after the database is upgraded.

Upgrade Time Zone Data: Select this option to update the time zone data file for this release. If you do not select this option, then you must update the time zone configuration file manually after the upgrade.

Gather Statistics Before Upgrade: Select this option to gather statistics about your existing databases before running the installation.

Set User Tablespaces to Read Only During the Upgrade : Select this option to prevent user attempts to write to tablespaces during the upgrade.

Specify custom SQL scripts to be executed : If you want to run custom SQL scripts as part of your upgrade, then select this box. As needed, click Browse for the Before Upgrade or After Upgrade input fields. Navigate to the location where your custom SQL scripts are located.

upgrade options


  • The Select Recovery Options window appears which provides the below: Select from one of the following options to recover the database if a failure occurs during upgrade:

• Use RMAN Backup : You can create a new offline RMAN backup, or use an existing backup. Click Browse to specify a path for the backup.
• Use Latest Available RMAN Backup : You can use an existing backup. Click View/Edit Restore to select the backup that you want to use.
• Use Flashback and Guaranteed Restore Point : You can create a new Guaranteed Restore Point, or use an existing one. If you use an existing restore point, then click the selection field to select the restore point that you want to use.
• I have my own backup and restore strategy : Select this option only if you have a third-party backup solution in place for your existing database. When you have made your selections, click Next.




  • The Listener Selection area /tab of the Network Configuration window shows the existing listener of source Oracle Home.

You can also select to create a new listener. If you create a new listener, then provide the listener name and the port that you want to configure the listener to monitor. After you make your choices, DBUA completes the following steps for any listeners that you migrate:

a. DBUA adds the selected listener to the listener.ora file of the target Oracle home, and starts it.
b. DBUA removes the entry of the upgraded database from the old (source) listener.ora file.
c. DBUA reloads the listener.ora file in both the source and target Oracle Database environments.

If there are other databases registered with the same listener, then their new client connection requests can be affected during listener migration.




  • The Configure Management Options window appears. In the Configure Management window, select the management options:

• Configure Enterprise Manager (EM) Database Express : Oracle Enterprise Manager Database Express is a web-based database management application that is built into Oracle Database 12c. EM Express replaces the DB Control component that was available in releases 10g and 11g. Enter the EM Database Express Port number. For example: 5502.
• Register with Enterprise Manager (EM) Cloud Control:  Registering with Oracle Enterprise Manager Cloud Control adds the database and its related entities, such as Listener, Oracle ASM disk groups, and Oracle Clusterware, as targets that you can manage with EM Cloud Control. If you select this option, then you must provide information in the followingfields:
– OMS Host
– OMS Port
– EM Admin Username
– EM Admin Password
– DBSNMP User Password




  •  The Summary window opens. The Summary window shows the information about the upgrade you have configured before the starts. Scroll down the list to review all the details. Information in the summary includes information such as the following:

• Source Database
• Target Database
• Pluggable Databases
• Pre-Upgrade Checks
• Initialization Parameters changes
• Timezone Upgrade
Check all of the details to ensure that the selections are the ones you want. Then click either Back, or Finish :
• Click Back if you see something in the Summary window that you need to correct. Navigate backward through the DBUA configuration interview until you return to the window where you can correct it.
• Click Finish if the information you see in the Summary window is correct, and you want the upgrade to begin.




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