oracle 12C的新特性-CDB和PDB

1.前言

CDB与PDB是Oracle 12C引入的新特性，在ORACLE 12C数据库引入的多租用户环境（Multitenant Environment）中，允许一个数据库容器（CDB）承载多个可插拔数据库（PDB）。CDB全称为ContainerDatabase，中文翻译为数据库容器，PDB全称为Pluggable Database，即可插拔数据库。在ORACLE 12C之前，实例与数据库是一对一或多对一关系（RAC）：即一个实例只能与一个数据库相关联，数据库可以被多个实例所加载。而实例与数据库不可能是一对多的关系。当进入ORACLE 12C后，实例与数据库可以是一对多的关系。
关于CDB与PDB的关系图

12c中 oracle引入了容器数据库 CDB（container database），和可插拔数据库 PDB（pluggable database）。oracle 将CDB看成一个容器，用来存放数据库。
在CDB中可以有多个PDB，其中存在一个root根容器（PDB$ROOT）、一个种子容器（PDB$SEED）和多个PDBS。所有的PDB共用一个硬件系统资源、sga和pga、redo、临时段、控制文件、参数文件、还原段（还可对每个PDB单独指定）。

PDB$ROOT：根容器用来做所有容器的跟，用来对每个PDB进行统一管理，sqlplus / as  sysdba连接进来默认是连接的根容器，需要切换到其他的PDB容器才可以对单独的PDB操作。其中有 system数据文件、sysaux数据文件、（undo数据文件、temp数据文件、redo、控制文件）。一般不存放生产数据文件

PDB$SEED：种子容器作为插入PDB的模板而存在，每个CDB都有一个种子容器，且不可对其中对象进行修改。其中有 system数据文件、sysaux数据文件、其他数据文件。

PDB：新插入容器，该容器用来存放数据库。其中有 system数据文件、sysaux数据文件、其他数据文件。12c中可以插入多个容器进行统一管理，来减少BDA的工作量。其中的数据库可以插入或拔出。

用户：12c中PDB$ROOT中的普通目录可以通过权限分配来访问一个或多个指定的PDB容器，最大权限用户是sysdba。其中PDB也可单独创建普通用户来管理该容器的数据库。

PDB资源管理：12c中将多个数据库运行在一个硬件资源上，CDB性能上得到优化。在CDB中为每个PDB确定使用CPU最低份额，CDB会按照一个PDB份额/分配的总份额数*100%，来保证PDB最低份额数。

容器管理

连接数据库

[oracle@master ~]$ sqlplus / as sysdba

查询该容器是CDB 还是非CDB

SQL> select name,cdb,open_mode,con_id from v$database;

NAME      CDB OPEN_MODE                CON_ID
--------- --- -------------------- ----------
ORCL      YES READ WRITE                    0

查看当前容器

SQL> show con_name;

CON_NAME
------------------------------
CDB$ROOT

查看所创建的PDB

SQL>  show pdbs;

    CON_ID CON_NAME                       OPEN MODE  RESTRICTED
---------- ------------------------------ ---------- ----------
         2 PDB$SEED                       READ ONLY  NO
         3 PDBORCL                        MOUNTED

创建一个新PDB

SQL> create pluggable database pdb1 admin user pdb1 identified by pdb1 file_name_convert=('/u01/app/oracle/oradata/orcl/pdbseed/','/u01/app/oracle/oradata/orcl/pdb1/');

Pluggable database created.

SQL> show pdbs;

    CON_ID CON_NAME                       OPEN MODE  RESTRICTED
---------- ------------------------------ ---------- ----------
         2 PDB$SEED                       READ ONLY  NO
         3 PDBORCL                        MOUNTED
         4 PDB1                           MOUNTED

启动一个创建好的PDB

SQL> alter pluggable database pdb1 open;

Warning: PDB altered with errors.

SQL> select message,time from pdb_plug_in_violations;

MESSAGE
--------------------------------------------------------------------------------
TIME
---------------------------------------------------------------------------
Sync PDB failed with ORA-959 during 'CREATE USER c##dm_ca IDENTIFIED BY * PROFIL
E DEFAULT DEFAULT TABLESPACE casdb ACCOUNT UNLOCK container = all'
26-DEC-18 11.26.27.070262 AM


SQL> alter session set container=pdb1;

Session altered.

SQL> create tablespace users datafile '/u01/app/oracle/oradata/orcl/pdb1/users01.dbf' size 800M;

Tablespace created.

SQL> alter pluggable database pdb1 close;

Pluggable database altered.

SQL> alter pluggable database pdb1 open;

Warning: PDB altered with errors.             #还是会报错，不知是何原因了，查看没有报错信息

SQL> select message,time from pdb_plug_in_violations;

no rows selected

SQL> show pdbs;

    CON_ID CON_NAME                       OPEN MODE  RESTRICTED
---------- ------------------------------ ---------- ----------
         4 PDB1                           READ WRITE YES

也可以通过sqlplus使用传统的startup和shutdown命令来启动和关闭PDB

SQL> alter session set container=pdb1;
Session altered.
SQL>
SQL> show pdbs;

    CON_ID CON_NAME                       OPEN MODE  RESTRICTED
---------- ------------------------------ ---------- ----------
         4 PDB1                           MOUNTED
SQL> startup

Warning: PDB altered with errors.

Pluggable Database opened.
SQL> show pdbs;

    CON_ID CON_NAME                       OPEN MODE  RESTRICTED
---------- ------------------------------ ---------- ----------
         4 PDB1                           READ WRITE YES
SQL> shutdown immediate;
Pluggable Database closed.
SQL> show pdbs;

    CON_ID CON_NAME                       OPEN MODE  RESTRICTED
---------- ------------------------------ ---------- ----------
         4 PDB1                           MOUNTED
SQL> alter session set container=CDB$ROOT;

Session altered.

配置监听文件

监听文件目录在$ORACLE_HOME/network/admin

[oracle@master admin]$ cat tnsnames.ora 
# tnsnames.ora Network Configuration File: /u01/app/oracle/product/12.1.0/db_1/network/admin/tnsnames.ora
# Generated by Oracle configuration tools.

ORCL =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = master)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = orcl)
    )
  )

PDBORCL =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = master)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = PDBORCL)
    )
  )

PDB1 =
  (DESCRIPTION =
    (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.1.200)(PORT = 1521))
    (CONNECT_DATA =
      (SERVER = DEDICATED)
      (SERVICE_NAME = PDB1)
    )
  )

listener.ora 文件内容

[oracle@master admin]$ cat listener.ora 
# listener.ora Network Configuration File: /u01/app/oracle/product/12.1.0/db_1/network/admin/listener.ora
# Generated by Oracle configuration tools.

SID_LIST_LISTENER =
  (SID_LIST =
    (SID_DESC =
      (GLOBAL_DBNAME = orcl)
      (ORACLE_HOME = /u01/app/oracle/product/12.1.0/db_1)
      (SID_NAME = ORCL)
    )
   (SID_DESC=
      (GLOBAL_DBNAME = PDB1)
      (SID_NAME = PDB1)
    )
  )

LISTENER =
  (DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = TCP)(HOST = master)(PORT = 1521))
    )
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521))
    )
  )

ADR_BASE_LISTENER = /u01/app/oracle

测试一下

[oracle@master admin]$ tnsping pdb1

TNS Ping Utility for Linux: Version 12.1.0.2.0 - Production on 26-DEC-2018 11:55:36

Copyright (c) 1997, 2014, Oracle.  All rights reserved.

Used parameter files:
/u01/app/oracle/product/12.1.0/db_1/network/admin/sqlnet.ora


Used TNSNAMES adapter to resolve the alias
Attempting to contact (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = 192.168.1.200)(PORT = 1521)) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = PDB1)))
OK (0 msec)

连接pdb1

方法一：
[oracle@master admin]$  sqlplus sys/admin@pdb1 as sysdba

SQL*Plus: Release 12.1.0.2.0 Production on Wed Dec 26 14:23:22 2018

Copyright (c) 1982, 2014, Oracle.  All rights reserved.


Connected to:
Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production
With the Partitioning, OLAP, Advanced Analytics and Real Application Testing options

SQL> startup

Warning: PDB altered with errors.

Pluggable Database opened.
SQL> show pdbs;

    CON_ID CON_NAME                       OPEN MODE  RESTRICTED
---------- ------------------------------ ---------- ----------
         4 PDB1                           READ WRITE YES
SQL> 
方法二：
[oracle@master ~]$ sqlplus pdb1/pdb1@pdb1

SQL*Plus: Release 12.1.0.2.0 Production on Wed Dec 26 15:27:35 2018

Copyright (c) 1982, 2014, Oracle.  All rights reserved.


Connected to:
Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production
With the Partitioning, OLAP, Advanced Analytics and Real Application Testing options

SQL> 

oracle12C中在启动数据库的时候，PDB并不会随着CDB而启动。不过我们可以通过创建一个触发器让PDB能够随CDB启动。如下：

SQL> alter session set container=CDB$ROOT;

Session altered.

SQL> SHOW CON_NAME  

CON_NAME
------------------------------
CDB$ROOT
SQL> CREATE OR REPLACE TRIGGER open_pdbs
   AFTER STARTUP ON DATABASE
   BEGIN
   EXECUTE IMMEDIATE 'ALTER PLUGGABLE DATABASE ALL OPEN';
   END open_pdbs;
    /
Trigger created.

重新启动数据库：

[oracle@master ~]$ sqlplus / as sysdba

SQL*Plus: Release 12.1.0.2.0 Production on Wed Dec 26 14:32:11 2018

Copyright (c) 1982, 2014, Oracle.  All rights reserved.


Connected to:
Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production
With the Partitioning, OLAP, Advanced Analytics and Real Application Testing options

SQL> show pdbs;

    CON_ID CON_NAME                       OPEN MODE  RESTRICTED
---------- ------------------------------ ---------- ----------
         2 PDB$SEED                       READ ONLY  NO
         3 PDBORCL                        READ WRITE NO
         4 PDB1                           READ WRITE YES

确实已经随着数据库启动，pdb1也启动起来。

但是，RESTRICTED 为YES

我重新创建一个pdb2

SQL> show con_name;

CON_NAME
------------------------------
CDB$ROOT
SQL> create pluggable database pdb2 admin user pdb2 identified by pdb2 file_name_convert=('/u01/app/oracle/oradata/orcl/pdbseed/','/u01/app/oracle/oradata/orcl/pdb2/');

Pluggable database created.

SQL> show pdbs;

    CON_ID CON_NAME                       OPEN MODE  RESTRICTED
---------- ------------------------------ ---------- ----------
         2 PDB$SEED                       READ ONLY  NO
         3 PDBORCL                        READ WRITE NO
         4 PDB1                           READ WRITE YES
         5 PDB2                           MOUNTED
SQL> alter pluggable database pdb2 open;

Pluggable database altered.

SQL> show pdbs;

    CON_ID CON_NAME                       OPEN MODE  RESTRICTED
---------- ------------------------------ ---------- ----------
         2 PDB$SEED                       READ ONLY  NO
         3 PDBORCL                        READ WRITE NO
         4 PDB1                           READ WRITE YES
         5 PDB2                           READ WRITE NO

pdb2完全正确。

pdb1解决如下：

SQL> select message from pdb_plug_in_violations where name='PDB1';

MESSAGE
--------------------------------------------------------------------------------
Sync PDB failed with ORA-959 during 'CREATE USER c##dm_ca IDENTIFIED BY * PROFIL
E DEFAULT DEFAULT TABLESPACE casdb ACCOUNT UNLOCK container = all'

Sync PDB failed with ORA-1918 during 'drop user c##dm_ca cascade'

SQL> alter session set container=PDB1;

Session altered.

SQL> select name from v$tablespace;

NAME
------------------------------
UNDOTBS1
SYSTEM
SYSAUX
TEMP
USERS

SQL> create tablespace casdb datafile '/u01/app/oracle/oradata/orcl/pdb1/casdb01.dbf' size 800M;

Tablespace created.

SQL> conn / as sysdba
Connected.

SQL> alter pluggable database pdb1 close;

Pluggable database altered.

SQL>  alter pluggable database pdb1 open;

Pluggable database altered.

SQL> show pdbs;

    CON_ID CON_NAME                       OPEN MODE  RESTRICTED
---------- ------------------------------ ---------- ----------
         2 PDB$SEED                       READ ONLY  NO
         3 PDBORCL                        READ WRITE NO
         4 PDB1                           READ WRITE NO
         5 PDB2                           READ WRITE NO
SQL>