Oracle Database 12C 学习之多租户（连载四）

使用克隆现存PDB的方式创建新的PDB：这里有两种情况，一种为使用本地PDB，另外一种为使用远程PDB。二者并无太大差异。只是第二种需要使用DBLINK而已。

克隆本地方式：

SYS@ora12g show pdbs;

CON_ID CON_NAME OPEN MODE RESTRICTED

---------- ------------------------------ ---------- ----------

 2 PDB$SEED READ ONLY NO

 3 ORA12C_PDB1 READ WRITE YES

 4 ORACDB_PDB2 READ WRITE NO

SYS@ora12g alter pluggable database ORA12C_PDB1 close;

Pluggable database altered.

SYS@ora12g alter pluggable database ORA12C_PDB1 open read only;

Pluggable database altered.

SYS@ora12g show pdbs;

CON_ID CON_NAME OPEN MODE RESTRICTED

---------- ------------------------------ ---------- ----------

 2 PDB$SEED READ ONLY NO

 3 ORA12C_PDB1 READ ONLY NO

 4 ORACDB_PDB2 READ WRITE NO

--我们这里克隆ORA12C_PDB1来创建新的PDB，需要先将其置于read only模式。

SYS@ora12c alter session set container=ORA12C_PDB1;

Session altered.

SYS@ora12c select file_name from dba_data_files;

FILE_NAME

--------------------------------------------------------------------------------

/u01/oracle/oradata/ora12c/ora12c_pdb1/system01.dbf

/u01/oracle/oradata/ora12c/ora12c_pdb1/sysaux01.dbf

/u01/oracle/oradata/ora12c/ora12c_pdb1/SAMPLE_SCHEMA_users01.dbf

/u01/oracle/oradata/ora12c/ora12c_pdb1/example01.dbf

SYS@ora12c create pluggable database ORA12C_PDB2

from ORA12c_PDB1

file_name_convert = (/u01/oracle/oradata/ora12c/ora12c_pdb1,

/u01/oracle/oradata/ora12c/ora12c_pdb2)

storage (MAXSIZE 4G MAX_SHARED_TEMP_SIZE 100M); 2 3 4 5

create pluggable database ORA12C_PDB2

ERROR at line 1:

ORA-65040: operation not allowed from within a pluggable database

--不能在PDB中复制PDB。

SYS@ora12c alter session set container=CDB$ROOT;

Session altered.

SYS@ora12c create pluggable database ORA12C_PDB2

from ORA12C_PDB1

file_name_convert = (/u01/oracle/oradata/ora12c/ora12c_pdb1,

/u01/oracle/oradata/ora12c/ora12c_pdb2)

storage (MAXSIZE 4G MAX_SHARED_TEMP_SIZE 100M);

2 3 4 5

Pluggable database created.

--目标PDB的数据文件存储目录也可以不用事先创建，oracle会自动创建。

--可以在创建PDB的同时指定该PDB的空间使用限额。

SYS@ora12c show pdbs;

CON_ID CON_NAME OPEN MODE RESTRICTED

---------- ------------------------------ ---------- ----------

 2 PDB$SEED READ ONLY NO

 3 ORA12C_PDB1 READ ONLY NO

 4 ORACDB_PDB2 READ WRITE NO

 5 ORA12C_PDB2 MOUNTED

使用远程PDB创建：

SYS@ora12c show pdbs;

CON_ID CON_NAME OPEN MODE RESTRICTED

---------- ------------------------------ ---------- ----------

 2 PDB$SEED READ ONLY NO

 3 ORA12C_PDB1 READ ONLY NO

 4 ORACDB_PDB2 READ WRITE NO

 5 ORA12C_PDB2 MOUNTED

SYS@ora12c conn sys/oracle@ORACDB_PDB2 as sysdba

Connected.

SYS@ORACDB_PDB2 shutdown immediate;

Pluggable Database closed.

SYS@ORACDB_PDB2 startup;

Pluggable Database opened.

SYS@ORACDB_PDB2 show pdbs;

CON_ID CON_NAME OPEN MODE RESTRICTED

---------- ------------------------------ ---------- ----------

 4 ORACDB_PDB2 READ WRITE NO

SYS@ORACDB_PDB2 create user remote_pdb identified by remote;

User created.

SYS@ORACDB_PDB2 grant create pluggable database to remote_pdb;

Grant succeeded.

--在源PDB中创建拥有create PDB权限的用户。

SYS@ORACDB_PDB2 conn / as sysdba

Connected.

SYS@ora12g create database link dbl_pdb connect to remote_pdb identified by remote using ORACDB_PDB2;

Database link created.

--我们这里以ORACDB_PDB2作为远程数据库，也就是创建PDB的源PDB。

--利用前面创建的用户创建db link。

SYS@ora12c alter pluggable database ORACDB_PDB2 open read only force;

Pluggable database altered.

SYS@ora12c show pdbs;

CON_ID CON_NAME OPEN MODE RESTRICTED

---------- ------------------------------ ---------- ----------

 2 PDB$SEED READ ONLY NO

 3 ORA12C_PDB1 READ ONLY NO

 4 ORACDB_PDB2 READ ONLY NO

 5 ORA12C_PDB2 MOUNTED

--同样将其置于read only状态。

SYS@ora12c create pluggable database ORACDB_PDB_NEW

from ORACDB_PDB2@dbl_pdb

file_name_convert = (/u01/oracle/oradata/ora12c/cdb/pdb2,

/u01/oracle/oradata/ora12c/cdb/pdb2_new); 2 3 4

Pluggable database created.

SYS@ora12c show pdbs;

CON_ID CON_NAME OPEN MODE RESTRICTED

---------- ------------------------------ ---------- ----------

 2 PDB$SEED READ ONLY NO

 3 ORA12G_PDB1 READ ONLY NO

 4 ORACDB_PDB2 READ ONLY NO

 5 ORA12C_PDB2 MOUNTED

 6 ORACDB_PDB_NEW MOUNTED

克隆非CDB的数据库来创建PDB。

这里有三种方法：

1，使用DBMS_PDB包生成源数据库的元数据，然后再利用create pluggable database语句创建；

2，使用数据泵（可传输表空间）；

3，使用OGG。

使用数据泵方式，请参考官方文档Oracle® Database Utilities 12c Release 1 (12.1)

使用OGG方式，请参阅OGG相关文档。

我们这里测试下第一种方式。

1，先创建一个新的非CDB数据库。我们这里用DBCA创建。这步我就不多写了。各位一路next下去就好。记得别勾选create as a container database即可。

另外需要注意的是，数据库版本必须得是12c或者更高版本。

2，将该数据库以read only模式打开

[oracle@ora12 ~]$ sqlplus / as sysdba

SQL*Plus: Release 12.1.0.2.0 Production on Fri Dec 18 09:56:43 2015

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

SYS@noncdb shutdown immediate;

Database closed.

Database dismounted.

ORACLE instance shut down.

SYS@noncdb startup mount;

ORACLE instance started.

Total System Global Area 838860800 bytes

Fixed Size 2929936 bytes

Variable Size 599788272 bytes

Database Buffers 230686720 bytes

Redo Buffers 5455872 bytes

Database mounted.

SYS@noncdb alter database open read only;

Database altered.

--这里，数据库需要开归档才能以read only模式打开，至于原因嘛，恩，各位小伙伴应该都能想的出来吧

3，利用DBMS_PDB包生成该数据库的pdb描述文件并关闭数据库。

SYS@noncdb begin

dbms_pdb.describe(pdb_descr_file = /home/oracle/noncdb.xml);

PL/SQL procedure successfully completed.

SYS@noncdb 

SYS@noncdb shutdown immediate;

Database closed.

Database dismounted.

ORACLE instance shut down.

--这里生成的pdb描述文件为xml格式的，各位可以进去看一下它的内容。

--该文件中包含了数据库的版本信息，非默认值的初始化参数信息，表空间及数据文件信息，其他可选组件的版本信息，service信息，以及AWR中loadprofile的内容。

4，登陆CDB，检测要插入的pdb是否存在兼容性问题

SYS@ora12c set serveroutput on

declare

test_via boolean;

begin

test_via := dbms_pdb.check_plug_compatibility(pdb_descr_file = /home/oracle/noncdb.xml);

if test_via then

dbms_output.put_line(Yes);

dbms_output.put_line(No);

end if;

PL/SQL procedure successfully completed.

--输出结果为yes，表示没有兼容性问题。

--如果为no，则需要去检查pdb_plug_in_violations视图。

5，创建PDB

SYS@ora12c create pluggable database PDB_NEW

using /home/oracle/noncdb.xml

file_name_convert = (/u01/oracle/oradata/noncdb,

/u01/oracle/oradata/cdb/pdb_new);

Pluggable database created.

SYS@ora12c show pdbs;

CON_ID CON_NAME OPEN MODE RESTRICTED

---------- ------------------------------ ---------- ----------

 2 PDB$SEED READ ONLY NO

 3 PDB_NEW MOUNTED

6，执行脚本

SYS@ora12c conn sys/oracle@ora12:1521/PDB_NEW as sysdba;

Connected.

SYS@ora12:1521/PDB_NEW @?/rdbms/admin/noncdb_to_pdb.sql;

--该脚本的用处是：更新非CDB的数据库中的数据字典表，将其调整为PDB。

执行完成之后，该PDB就可以使用了。

需要注意的是：

在执行该脚本的时候，建议同时查看alert 日志，因为我的虚拟机只有2G内存，然后新创建的这个数据库noncdb我将其内存设置为了800M。所以在将该数据库创建为PDB时，oracle需要调整其参数设置。alert 日志中就看到如下类似的内容：

Active Session History (ASH) performed an emergency flush. This may mean that ASH is undersized. If emergency flushes are a recurring issue, you may consider increasing ASH size by setting the value of _ASH_SIZE to a sufficiently large value. Currently, ASH size is 2097152 bytes. Both ASH size and the total number of emergency flushes since instance startup can be monitored by running the following query:

select total_size,awr_flush_emergency_count from v$ash_info;

以及：

Default pga_aggregate_limit value is too high for the

amount of physical memory in the system

pga_aggregate_limit is 2048 MB

limit based on physical memory and SGA usage is 1285 MB

因此，在虚拟机上创建新的PDB时，需要考虑内存以及其他比如说磁盘容量等方面的限制。

从CDB中拔出和插入PDB：

3 file_name_convert = (/u01/oracle/oradata/ora12c/pdbseed,/u01/oracle/oradata/ora12c/cdb/pdb1); Pluggable database created. SYS@ora12c show pdbs; CON_ID CON_NAME OPEN MODE RESTRICTED ---------- ------------------------------ ---------- ---------- 2 PDB$SEED READ ONLY NO 3 PDB1 MOUNTED SYS@ora12c alter pluggable database PDB1 open; Pluggable database altered. SYS@ora12c show pdbs; CON_ID CON_NAME OPEN MODE RESTRICTED ---------- ------------------------------ ---------- ---------- 2 PDB$SEED READ ONLY NO 3 PDB1 READ WRITE NO SYS@ora12c alter pluggable database PDB1 close; Pluggable database altered.

--需要先关闭可插拔数据库，然后再unplug。

SYS@ora12c alter pluggable database PDB1

unplug into /home/oracle/pdb1.xml;

Pluggable database altered.

--需要注意的是，这里只是unplug了，实际上该PDB还存在。如果想重新插入该PDB，则需要先删除。

SYS@ora12c drop pluggable database PDB1;

Pluggable database dropped.

插入PDB的时候，首先需要做兼容性检查。也就是上篇文章中提到的DBMS_PDB.check_plug_compatibility函数。

如果没有问题，再插入。

插入语句跟创建新的PDB一样

SYS@ora12c create pluggable database PDB1

using /home/oracle/pdb1.xml

file_name_convert = (/u01/oracle/oradata/pdb1,

/u01/oracle/oradata/cdb/pdb_new);

使用DBCA创建PDB的方式，这里不再多说

本文来自云栖社区合作伙伴“DBGEEK”

Oracle 12c之后CDB上创建公共用户无法访问PDB 上v$session表内容 Oracle 12c CDB模式下，创建公共用户，登录到CDB，无法查看PDB下一些表的信息，如v$session，登录到具体PDB才能看到，这篇文章将介绍如何给公共用户授权解决这个问题。
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