Before 12c there are only few commands available for startup and shutdown but if we follow that we may end up starting and stopping the PDBs and CDB as well.
shutdown normal shutdown immediate shutdown abort startup startup nomount startup mount
If we use one of these traditional shutdown methods at the container database (CDB) layer, we will bring down the CDB and the associated PDBs under it. This is something to be aware of when looking to reboot a container database. Let’s take a look at bringing down a CDB.
SQL> select instance_name from v$instance; INSTANCE_NAME ---------------- ora12c
SQL> show con_name; CON_NAME ------------------------------ CDB$ROOT
SQL> shutdown immediate; Database closed. Database dismounted. ORACLE instance shut down.
SQL> alter session set container=PDB1; alter session set container=PDB1 * ERROR at line 1: ORA-01034: ORACLE not available Process ID: 0 Session ID: 0 Serial number: 0
Thus, a SHUTDOWN IMMEDIATE at the CDB level will close the CDB and all other PDBs under than CDB.
How can we shutdown just a single PDB if needed?
There are two different ways to shutdown a PDB.
1. The first of which is from the CDB layer.
We use this method for maintenance purpose without affecting other pdb. We can shutdown a PDB from the CDB level using the ALTER PLUGGABLE DATABASE command.
alter pluggable database open read write alter pluggable database open read only alter pluggable database open upgrade alter pluggable database close
For example, first find out current state of pdb’s:
SQL> select con_id, name, open_mode from v$pdbs; CON_ID NAME OPEN_MODE ---------- ------------------------------ ---------- 2 PDB$SEED READ ONLY 3 PDB1 MOUNTED 4 PDBTEST MOUNTED 5 PDB2 MOUNTED
Top open a particular PDB named PDB1, use the below query:
SQL> alter pluggable database PDB1 open; Pluggable database altered.
SQL> select con_id, name, open_mode from v$pdbs; CON_ID NAME OPEN_MODE ---------- ------------------------------ ---------- 2 PDB$SEED READ ONLY 3 PDB1 READ WRITE 4 PDBTEST MOUNTED 5 PDB2 MOUNTED
Open command in pdb is ‘alter pluggable database’ and not ‘startup’.
2. The second of which of from the PDB layer:
We can use the normal SHUTDOWN commands as we would with a traditional database. In order to do this, we have to be in that PDB container first. Here is an example of closing PDB1 with the SHUTDOWN command. For example:
SQL> alter session set container=PDB1; Session altered.
SQL> select con_id, name, open_mode from v$pdbs; CON_ID NAME OPEN_MODE ---------- ------------------------------ ---------- 3 PDB1 READ WRITE SQL> shutdown immediate; Pluggable Database closed.
SQL> select con_id, name, open_mode from v$pdbs; CON_ID NAME OPEN_MODE ---------- ------------------------------ ---------- 3 PDB1 MOUNTED