Database Reference
In-Depth Information
Once you connect to the pdb1 PDB, you can do administrative tasks such as creating schema or other database
objects in the PDB. These default database services should be used only for administrative tasks. Additional database
services should be created for the applications to connect to the PDBs. The next section will discuss how to create
additional services for PDBs in the Oracle RAC environment.
PDBs on Oracle RAC
The CDB with PDBs can be created and configured on a single-node or a multiple-node RAC environment. Similarly
to a non-CDB database, a RAC-based containter database can be shared and accessed through multiple database
instances on the RAC nodes. However, the CDB has introduced several layers of containers in the database: the entire
CDB, the root, the seed, and PDBs. Similar to the non-CDB, a PDB can be on different open modes:
•
Mounted
•
Read only
•
Read and write
You can check the open modes of all the PDBs on a RAC instance when you connect to the CDB root:
SELECT NAME, OPEN_MODE, RESTRICTED FROM V$PDBS;
NAME OPEN_MODE RESTRICTED
-------- ---------- ----------
PDB$SEED READ ONLY NO
PDB1 READ WRITE NO
PDB2 READ WRITE NO
PDB3 Mounted NO
To start a PDB, connect to the PDB with SQL*Plus and run the startup or the shutdown command with different
startup open options:
STARTUP OPEN
STARTUP OPEN READ ONLY
STARTUP RESTRICT OPEN READ ONLY
SHUTDOWN IMMEDIATE
You also can change the open mode of a PDB using the ALTER PLUGGABLE DATABASE statement, for example,
'ALTER PLUGGABLE DATABASE CLOSE IMMEDIATE' to close the PDB, 'ALTER PLUGGABLE DATABASE OPEN
READ ONLY' to open the PDB for read only.
Figure
4-10
shows such a RAC-based CDB database architecture. Each PDB may be in the open mode in different
RAC instances: the pdb1 PDB is open on instance 1; pdb2 is open on instance 2; pdb3 is open on instances 1, 2, and 3;
and pdb4 is open on instance 3.
