In case you missed the previous posts:
- Part 1 – Refreshable Clone PDBs
- Part 2 – Non-CDB 19c to 23ai PDB
- Part 3 – 19c PDB to 23ai
- Part 4 – Fallback options
- Part 5 – Target_pdb_copy_option
As mentioned in a previous post, I was working on a workaround to have a 23ai database created with the Compatible parameter set to 19.
Having the Compatible set to 19, you will be able to use some of the known techniques to rollback the database upgrade, including:
- Run the catdwgrd.sql/ dbdowngrade
- Guarantee restore point
- Use Transportable Tablespaces
After going live, consider running the downgrading scripts if users have made changes to your Oracle Database and you encounter issues that cannot be resolved in time. While I never performed a downgrade during my 23 years of consulting after a production migration, I understand that customers often prefer having a rollback option as a safety measure.
Please check the documentation to learn more about downgrade.
To have a 23ai database with the parameter compatible set to 19c, you can create a new 19c CDB database:
There is no PDB yet:
You can use the console or the dbaascli to upgrade the 19c database to 23ai:
Select the target Oracle Home (23ai):
First, I will run the precheck:
The precheck was a success:
Let’s run the upgrade:
The upgrade is running:
After some time, it’s completed:
We now have a 19c database upgraded to 23ai:
And the compatible parameter is still 19:
Stay tuned for the next post.
Links to the Complete Blog Post Series on AutoUpgrade for ExaDB-D/ExaC@C: