The options to migrate to multitenant reuse the data files. The failback option is to use Data Pump to get back to a non-CDB, single-instance database. The recovery option is not necessarily faster, but the migration option is a simple and faster method.

If the recovery plan needed to be faster, then it might make more sense to copy the data files instead of reusing them. This will include copying and renaming the files with FILE_NAME_CONVERT.

It will take longer to migrate because there is a copy of the files before plugging in the database and migrating, but it will be a quicker rollback plan.

You create the manifest file and shut down the database. Copy the data files to a new location or to a new name.

In the target CDB, the next step to is create a PDB from the manifest file just created:

SQL> create pluggable database salesdb using ‘/tmp/salesdb.xml’ copy file_ name_convert=(‘SALES19C’,’SALESDB’);

One more migration to mention for plugging in a database is to clone the database over a database link. This consists of cloning a non-CDB single-instance database to a pluggable database in a CDB.

The autoupgrade command and the config file will make it easier to set up the options, and the database link makes it possible.

Here is the config file:

$ cat db19_to_23.cfg upgl.source_home=/u01/app/oracle/product/19 upgl.target_home=/u01/app/oracle/product/db23c upgl.sid=salesdbupgl.target_cdb=cdb23c upgl.target_pdb_name=salesdbupgl.target_pdb_copy_option=file_name_convert=(‘SALES19C’,’SALESDB’)

Run this command:

$ java -jar autoupgrade.jar -config db19_to23.cgf -mode deploy

Other options for migration options are some of the typical options for upgrades migrations, not just to a non-CDB to a container:

•     Data Pump

•     GoldenGate

•     Transportable tablespaces

These options keep the original database for a rollback plan, just like copying the data files. GoldenGate does allow for zero downtime, while the other migration options will require some downtime to copy, move, and upgrade.

Tip there is a great resource for upgrades and migrations with Mike dietrich’s blog, upgrade your database – noW! he gives more details on these options and helps with planning for the migration.

Multitenant migration in 19c is a good first step to getting to 23c. You can upgrade and migrate at the same time as long as you are going from 19c. The upgrade path to 23c is from 19c or 21c. If you are using a non-CDB, single-instance database in 19c, then it makes sense to migrate the database to a pluggable database.