Startup and Shutdown
Container Databases (CDB) and Pluggable Databases (PDB) in Oracle Database 12c
Release 1 (12.1)
The multitenant option introduced in Oracle
Database 12c allows a single container database (CDB) to host multiple separate
pluggable databases (PDB). This article demonstrates how to startup and
shutdown container databases (CDB) and pluggable databases (PDB).
Container Database (CDB)
Startup and shutdown of the container database
is the same as it has always been for regular instances. The SQL*Plus STARTUP and
SHUTDOWN commands are available when connected to the CDB as a privileged user.
Some typical values are shown below.
STARTUP [NOMOUNT | MOUNT | RESTRICT | UPGRADE |
FORCE | READ ONLY]
SHUTDOWN [IMMEDIATE | ABORT]
Pluggable Database (PDB)
Pluggable databases can be started and stopped
using SQL*Plus commands or the ALTER PLUGGABLE DATABASE command.
SQL*Plus Commands
STARTUP FORCE;
STARTUP OPEN READ WRITE [RESTRICT];
STARTUP OPEN READ ONLY [RESTRICT];
STARTUP UPGRADE;
SHUTDOWN [IMMEDIATE];
Some examples are shown below.
STARTUP FORCE;
SHUTDOWN IMMEDIATE;
STARTUP OPEN READ WRITE RESTRICT;
SHUTDOWN;
STARTUP;
SHUTDOWN IMMEDIATE;
ALTER PLUGGABLE DATABASE
The ALTER PLUGGABLE DATABASE command can be used
from the CDB or the PDB.
The following commands are available to open and
close the current PDB when connected to the PDB as a privileged user.
ALTER PLUGGABLE DATABASE OPEN READ WRITE
[RESTRICTED] [FORCE];
ALTER PLUGGABLE DATABASE OPEN READ ONLY [RESTRICTED]
[FORCE];
ALTER PLUGGABLE DATABASE OPEN UPGRADE [RESTRICTED];
ALTER PLUGGABLE DATABASE CLOSE [IMMEDIATE];
Some examples are shown below.
ALTER PLUGGABLE DATABASE OPEN READ ONLY FORCE;
ALTER PLUGGABLE DATABASE CLOSE IMMEDIATE;
ALTER PLUGGABLE DATABASE OPEN READ WRITE;
ALTER PLUGGABLE DATABASE CLOSE IMMEDIATE;
The following commands are available to open and close one or more PDBs when connected to the CDB as a privileged user.
ALTER PLUGGABLE DATABASE <pdb-name-clause>
OPEN READ WRITE [RESTRICTED] [FORCE];
ALTER PLUGGABLE DATABASE <pdb-name-clause>
OPEN READ ONLY [RESTRICTED] [FORCE];
ALTER PLUGGABLE DATABASE <pdb-name-clause>
OPEN UPGRADE [RESTRICTED];
ALTER PLUGGABLE DATABASE <pdb-name-clause>
CLOSE [IMMEDIATE];
The<pdb-name-clause> clause can be any of the following:
- One or more PDB names, specified as a comma-separated
list.
- The ALL keyword
to indicate all PDBs.
- The ALL EXPECT keywords,
followed by one or more PDB names in a comma-separate list, to indicate a
subset of PDBs.
Some examples are shown below.
ALTER PLUGGABLE DATABASE pdb1, pdb2 OPEN READ ONLY
FORCE;
ALTER PLUGGABLE DATABASE pdb1, pdb2 CLOSE IMMEDIATE;
ALTER PLUGGABLE DATABASE ALL OPEN;
ALTER PLUGGABLE DATABASE ALL CLOSE IMMEDIATE;
ALTER PLUGGABLE DATABASE ALL EXCEPT pdb1 OPEN;
ALTER PLUGGABLE DATABASE ALL EXCEPT pdb1 CLOSE
IMMEDIATE;
Pluggable Database (PDB) Automatic Startup
The 12.1.0.2 patchset has introduced the ability
to preserve the startup state of PDBs, so you probably shouldn't be
implementing a trigger in the manner discussed in this section.
Prior to 12.1.0.2, when the CDB is started, all
PDBs remain in mounted mode. There is no default mechanism to automatically
start them when the CDB is started. The way to achieve this is to use a system
trigger on the CDB to start some or all of the PDBs.
CREATE OR REPLACE TRIGGER open_pdbs
AFTER
STARTUP ON DATABASE
BEGIN
EXECUTE
IMMEDIATE 'ALTER PLUGGABLE DATABASE ALL OPEN';
END open_pdbs;/
You can customise the trigger if you don't want
all of your PDBs to start.
Preserve PDB Startup State (12.1.0.2 onward)
The 12.1.0.2 patchset introduced the ability to
preserve the startup state of PDBs through a CDB restart. This is done using
the ALTER PLUGGABLE DATABASE command.
We will start off by looking at the normal
result of a CDB restart. Notice the PDBs are in READ WRITE mode before the
restart, but in MOUNTED mode after it.
SELECT name, open_mode FROM v$pdbs;
NAME OPEN_MODE
------------------------------ ----------
PDB$SEED READ ONLY
PDB1 READ WRITE
PDB2 READ WRITE
SQL>
SHUTDOWN IMMEDIATE;
STARTUP;
SELECT name, open_mode FROM v$pdbs;
NAME OPEN_MODE
------------------------------ ----------
PDB$SEED READ ONLY
PDB1 MOUNTED
PDB2 MOUNTED
SQL>
Next, we open both pluggable databases, but only
save the state of PDB1.
ALTER PLUGGABLE DATABASE pdb1 OPEN;
ALTER PLUGGABLE DATABASE pdb2 OPEN;
ALTER PLUGGABLE DATABASE pdb1 SAVE STATE;
The DBA_PDB_SAVED_STATES view displays
information about the saved state of containers.
COLUMN con_name FORMAT A20
COLUMN instance_name FORMAT A20
SELECT con_name, instance_name, state FROM
dba_pdb_saved_states;
CON_NAME
INSTANCE_NAME STATE
-------------------- --------------------
--------------
PDB1 cdb1 OPEN
SQL>
Restarting the CDB now gives us a different
result.
SELECT name, open_mode FROM v$pdbs;
NAME OPEN_MODE
------------------------------ ----------
PDB$SEED READ ONLY
PDB1 READ WRITE
PDB2 READ WRITE
SQL>
SHUTDOWN IMMEDIATE;
STARTUP;
SELECT name, open_mode FROM v$pdbs;
NAME OPEN_MODE
------------------------------ ----------
PDB$SEED READ ONLY
PDB1 READ WRITE
PDB2 MOUNTED
SQL>
The saved state can be discarded using the
following statement.
ALTER PLUGGABLE DATABASE pdb1 DISCARD STATE;
COLUMN con_name FORMAT A20
COLUMN instance_name FORMAT A20
SELECT con_name, instance_name, state FROM
dba_pdb_saved_states;
no rows selected
SQL>
- The state is only saved and visible in the DBA_PDB_SAVED_STATES
view if the container is in READ ONLY or READ WRITE mode.
The ALTER PLUGGABLE DATABASE... SAVE STATE command does not error when run against a container In MOUNTED mode, but
nothing is recorded, as this is the default state after a CDB restart.
- Like other examples of the ALTER PLUGGABLE DATABASE command,
PDBs can be identified individually, as a comma separated list, using the
ALL or ALL EXPECT keywords.
- The INSTANCES clause can be added when used in RAC
environments. The clause can identify instances individually, as a comma
separated list, using the ALL or ALL EXPECT keywords. Regardless of the
INSTANCES clause, the SAVE/DISCARD STATE commands only affect
the current instance.
No comments:
Post a Comment