Oracle DBA Lesson 27B — Keeping a PDB Open After Restart

Opening a pluggable database makes it available for current work. SAVE STATE preserves its intended open mode so Oracle reopens that PDB when the CDB starts.

Oracle DBA Lesson 27B — Keeping a PDB Open After Restart

The example continues with LABPDB open READ WRITE, with RESTRICTED equal to NO. The previous lesson covered choosing and changing that current mode. Here the task is to preserve the intended state, inspect the saved record, and verify the PDB after restart. Oracle PDB administration guide.

Current state and saved state

These two views answer different questions:

Question	View	Useful columns
What is the PDB's mode now?	V$PDBS	NAME, OPEN_MODE, RESTRICTED
What state is saved for restart?	DBA_PDB_SAVED_STATES	CON_NAME, INSTANCE_NAME, STATE, RESTRICTED

INSTANCE_NAME associates a saved record with an instance. In this single-instance example there is one relevant instance. Read the row for that instance. Oracle DBA_PDB_SAVED_STATES reference.

Save the intended open state

Check that the PDB is in the state you intend to preserve:

SELECT name, open_mode, restricted
FROM v$pdbs
WHERE name = 'LABPDB';

For the example, expect LABPDB, READ WRITE, NO. If the PDB is still in a temporary maintenance mode, set the intended mode before you save it.

Run the named command from CDB$ROOT:

ALTER PLUGGABLE DATABASE LABPDB SAVE STATE;

This records the PDB's open state and restricted-access setting for restart. Oracle uses that record when the CDB starts again. Oracle ALTER PLUGGABLE DATABASE reference.

Inspect the record:

SELECT con_name, instance_name, state, restricted
FROM dba_pdb_saved_states
WHERE con_name = 'LABPDB';

CON_NAME	INSTANCE_NAME	STATE	RESTRICTED
LABPDB	CDB1	OPEN	NO

CDB1 is the example instance name. Yours may differ. OPEN is the saved-state value used for this read-write example. Oracle's 19c training material shows STATE = OPEN alongside a PDB that is READ WRITE before and after restart. Use V$PDBS.OPEN_MODE for the actual current mode. Oracle University Gold DBA startup example.

When the intended state changes later, apply the new mode and run SAVE STATE again. The saved record follows the setting you explicitly save. Oracle worked example.

Verify after the CDB restarts

Save the intended state, restart the CDB, then check the PDB's actual mode. In this example, Oracle restores LABPDB to READ WRITE with unrestricted access. Oracle PDB restart behavior.

After restart, repeat the current-state query. Confirm OPEN_MODE and RESTRICTED. Then connect through the application's service and check the destination:

SHOW CON_NAME

SELECT SYS_CONTEXT('USERENV', 'CON_NAME') AS container_name
FROM dual;

SHOW CON_NAME is a SQL*Plus command. The query is SQL. Both show whether the connected container is LABPDB. Using the application's connection path checks access as well as the reported mode.

PDB state and the application service are administered together during maintenance. Use the service's configured owner and startup policy. Oracle Restart or Clusterware-managed services use their own management tools. Oracle PDB services.

Restore the default restart setting

ALTER PLUGGABLE DATABASE LABPDB DISCARD STATE;

DISCARD STATE removes the saved restart record. A currently open PDB stays open. With no saved state, that PDB is MOUNTED after the next CDB restart. Query both views again: current mode in V$PDBS, and no saved row for that instance in DBA_PDB_SAVED_STATES. Oracle DISCARD STATE syntax.

Practice

Use Oracle Database 19c in an authorized disposable single-instance CDB. Run the named commands from CDB$ROOT with an approved account. This course uses AS SYSDBA. Reading the views needs catalog access. Oracle documents the save and discard operation from the root. Oracle PDB administration prerequisites.

1. Record LABPDB's current mode, restriction flag, and any existing saved row.
2. Confirm the intended open mode, save it, and inspect the row for this instance.
3. In an agreed isolated outage, an authorized administrator can use SHUTDOWN IMMEDIATE followed by STARTUP from root. This stops and restarts the CDB instance and all of its PDBs. Applications disconnect during the outage.
4. Verify the current mode, restriction flag, and application-service connection.
5. Restore the starting configuration. If there was no original saved record, discard the new one. If a record existed, restore its original intended mode and restriction, then save that state again. Restore any separately changed current mode as well.

Record the actual results and the difference between the current mode and the saved row. Startup triggers, service automation, or management policies can also change restart behavior. Identify those in the designated environment before the restart exercise.

Quiz

1. LABPDB is READ WRITE with unrestricted access. What should happen before SAVE STATE?

Confirm that this is its intended operating state Close every PDB in the CDB Set all PDBs to restricted access Restart the listener

2. Which column identifies the instance associated with a saved record?

CON_ID OPEN_MODE INSTANCE_NAME SESSION_USER

3. Which check shows LABPDB's actual mode after restart?

Read the SQL*Plus version banner Query V$PDBS.OPEN_MODE for LABPDB Inspect only the client alias name Count the rows in an application table

4. What happens immediately when DISCARD STATE runs on an open PDB?

The CDB instance shuts down The PDB's data files are deleted The PDB switches to READ ONLY The saved restart record is removed, and the PDB remains open

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