Provisioning, Cloning, and Resource Management
This domain covers creating and cloning PDBs and controlling their CPU and I/O consumption. Expect questions on the seed, file name conversion, hot cloning prerequisites, unplug/plug metadata, and CDB resource plan directives.
Provisioning and cloning
CREATE PLUGGABLE DATABASE ... ADMIN USER ... IDENTIFIED BY ... can source PDB$SEED, another local PDB, a remote PDB over a database link, or XML metadata. Use FILE_NAME_CONVERT or Oracle Managed Files to place datafiles. A hot clone of an open source PDB requires ARCHIVELOG mode and local undo mode. A remote clone uses FROM pdb@dblink. Before plugging into a CDB, run DBMS_PDB.CHECK_PLUG_COMPATIBILITY and inspect the result.
Unplug with ALTER PLUGGABLE DATABASE ... UNPLUG INTO '...xml' after closing the PDB. Plug with CREATE PLUGGABLE DATABASE ... USING '...xml' and SOURCE_FILE_NAME_CONVERT. DROP PLUGGABLE DATABASE ... INCLUDING DATAFILES removes the files; without that clause the datafiles remain.
Resource management
A CDB resource plan allocates resources among PDBs. Directives use SHARES for proportional CPU allocation during contention, UTILIZATION_LIMIT as a hard cap, and PARALLEL_SERVER_LIMIT. PDB I/O limits use MAX_IOPS and MAX_MBPS. Activate the plan by setting RESOURCE_MANAGER_PLAN in the root.
Worked example
Clone the open SALES PDB to SALES_TEST on another CDB: create a database link to the source, then run CREATE PLUGGABLE DATABASE sales_test FROM sales@src_link FILE_NAME_CONVERT=('/pdb/sales','/pdb/sales_test'); and open it. Because the source is open read-write, it must be in ARCHIVELOG with local undo. A cold clone from a closed PDB avoids those hot-clone requirements.
Traps
Unplugging requires the PDB to be closed. Plugging into a different CDB without checking compatibility can fail at open time. Shares are not hard limits; utilization limits are. Dropping a PDB without INCLUDING DATAFILES leaves orphan files. The resource plan has no effect until it is activated.