Download the binary for OTN and extract the ZIP file:

Choose “set up Software only” option:

Upgrading existing Oracle database from 12cR2 to 18c

In the unzipped binaries go to “bin” folder then search for dbua.bat file

 

You will see a list of pre-requisite checks that is being listed, in my case I will hit “Fix & Check Again” option….this will successfully eliminate the check with severity “Error” regarding recycle bin not being purged as shown below:

I accepted the warning message, press “Yes”

DBUA (Database Upgrade Assistant) is providing a rollback (recovery strategy) in case the upgrade fails, you have to choose on of three options:

• Flashback to guaranteed restore point
• Full RMAN backup – restore script is also provided as shown below
• You will be responcible for the recovery strategy

Wait until the upgrade finishes successfully !

After successfully upgrading your Oracle database, you can enable a new feature in 18c called “Read-Only” Oracle Homes .

This feature enables you take a software image, and separating configuration files. Also, it will improve your patching process as the patched (binaries) image can be distributed to other servers.