As I wrote before, the release you should upgrade to is clearly Oracle Database 19c. Unless you need to use one of the new features in Oracle 21c. But as you have seen in the past, some of them get backported to 19c as well. Still, in case you can’t resists or you love upgrades as much as we do, the question may be: Which releases allow you to upgrade to Oracle Database 21c?
The Database Upgrade Guide for Oracle 21c is your best friend here. Right at the beginning in the first chapter you will find this section:
Here you’ll see that you can upgrade directly from:
- Oracle Database 126.96.36.199
- Oracle Database 18c
- Oracle Database 19c
to Oracle Database 21c. Of course regardless of patch bundle. So it doesn’t make a difference whether you are on 18.4.0 or on 19.12.0. The direct upgrade support applies to the base release, e.g., 188.8.131.52, 18c or 19c, including all patch bundles. Always.
And you don’t have to patch your source.
For older releases you may need to take a decision. In case your downtime requirements are not a constraint, you can of course use Data Pump for every release change, even directly into Multitenant. But in some other cases you may need to do a double-hop in order to go to 21c. Alternatives may be Full Transportable Export Import or standard Transportable Tablespaces.
See our video here for more details. It has been made for 19c but the same concept applies to 21c as well.
Do I need to say this? There is exactly one recommended tool to upgrade your database – and this is AutoUpgrade. Since I read an SR last week where a Support engineer replied to an AutoUpgrade topic with “you should use DBUA” I feel tempted to repeat this again. AutoUpgrade – Step by Step is where you can start at.
And keep in mind that Oracle Database 21c does not allow the creation of non-CDBs anymore. You need to create an 21c CDB at first, and then lift your database(s) into it as I described in Upgrading a non-CDB database to Oracle Database 21c with AutoUpgrade.
Further Links and Information
- Oracle Database 21c: Database Upgrade Guide
- MOS Note: 2485457.1 – AutoUpgrade Tool Download
- AutoUpgrade – Step by Step
- Youtube Video: Double-Hop upgrades
- Double-Hop Upgrades
- Upgrading a non-CDB database to Oracle Database 21c with AutoUpgrade