1. Administering Oracle Database Exadata Cloud Service (OCI-C)
  2. Migrating Oracle Databases to Exadata Cloud Service
  3. Migration Methods
  4. Unplugging and Plugging a Pluggable Database

Unplugging and Plugging a Pluggable Database

You can use this method only if the source platform is little endian, and the database character set is AL32UTF8 or a compatible subset. It uses the multitenant architecture in Oracle Database 12c, or later, to enable easy migration of pluggable databases (PDBs).

You can migrate a PDB to Oracle Database Exadata Cloud Service by unplugging the PDB from the source container database (CDB) and plugging it into a CDB on Exadata Cloud Service.

This approach is attractive because of its simplicity. However, the specific requirements for this method make it suitable in fewer situations than other methods, such as transportable tablespaces. The requirements for unplugging and plugging a PDB include:

  • The source database must be a PDB, which implies that the source database version is 12.1 or later.

  • The source and target platform must have the same endian format, which is little-endian for Exadata Cloud Service.

  • Ideally, the source and target CDBs must use the same character set, which is AL32UTF8 for Exadata Cloud Service. Alternatively, the PDB character set must by a multibyte character set that is a binary subset of AL32UTF8, such as UTF8 for example; however, complications may arise if the different character sets have different maximum character widths.

To migrate a PDB to Exadata Cloud Service by unplugging and plugging a PDB, you perform these tasks:

  1. On the source database host, connect to the root container of the source CDB as a user with the SYSDBA or SYSOPER administrative privilege, and:

    1. Close the source PDB.

    2. Execute the ALTER PLUGGABLE DATABASE ... UNPLUG INTO command to generate an XML file containing the PDB metadata.

  2. Transfer the XML file and the PDB data files to an Exadata Cloud Service compute node.

  3. On the Exadata Cloud Service compute node, connect to the root container of the target CDB as a user with the SYSDBA or SYSOPER administrative privilege, and:

    1. Optionally, execute the DBMS_PDB.CHECK_PLUG_COMPATIBILITY function to verify that your PDB is compatible with Exadata Cloud Service.

    2. Execute the CREATE PLUGGABLE DATABASE command to plug in the PDB.

  4. Open the target PDB in read-write mode by executing the ALTER PLUGGABLE DATABASE ... OPEN READ WRITE command.

See Creating a PDB by Plugging an Unplugged PDB into a CDB in Oracle Database Administrator's Guide for Release 18, 12.2, or 12.1.

Alternatively, you can use RMAN to assist in the PDB migration process. By using RMAN you can avoid the requirement to place the source PDB into read-only mode. However, using RMAN requires that you use the BACKUP FOR TRANSPORT or BACKUP TO PLATFORM command to create a transportable backup of your source PDB. Therefore, using this method requires additional space and processing resources to create the required backup. See Performing Cross-Platform Transport of PDBs in Oracle Database Backup and Recovery User's Guide for Release 18, 12.2, or 12.1.