oracle12c cdb和pdb参数修改

12c的数据库启动参数文件只有一个,无论是cdb还是pdb使用这一个,但是其中这个参数文件其中只有cdb的数据库的参数.而没有pdb的参数.

SQL>show parameter spfile

NAME				     TYPE	 VALUE

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

spfile				     string	 /u01/app/oracle/product/12.1.0

/db_1/dbs/spfilesuq1.ora

查看参数文件的内容:

[oracle@12c1 ~]$ cat pfile.ora

suq1.__data_transfer_cache_size=0

suq1.__db_cache_size=444596224

suq1.__java_pool_size=4194304

suq1.__large_pool_size=8388608

suq1.__oracle_base='/u01/app/oracle'#ORACLE_BASE set from environment

suq1.__pga_aggregate_target=373293056

suq1.__sga_target=700448768

suq1.__shared_io_pool_size=25165824

suq1.__shared_pool_size=209715200

suq1.__streams_pool_size=0

*.audit_file_dest='/u01/app/oracle/admin/suq1/adump'

*.audit_trail='db'

*.compatible='12.1.0.2.0'

*.control_files='/u01/oradata/suq1/control01.ctl','/u01/flasharea/suq1/control02.ctl'

*.db_block_size=8192

*.db_domain=''

*.db_name='suq1'

*.db_recovery_file_dest='/u01/flasharea'

*.db_recovery_file_dest_size=4815m

*.diagnostic_dest='/u01/app/oracle'

*.dispatchers='(PROTOCOL=TCP) (SERVICE=suq1XDB)'

*.enable_pluggable_database=true

*.memory_target=1024m

*.open_cursors=600

*.processes=300

*.remote_login_passwordfile='EXCLUSIVE'

*.undo_tablespace='UNDOTBS1'

而pdb的参数分为两部分组成:

1.默认的pdb的参数由cdb参数指定

2.特别的如果手工指定了某pdb的参数,那么此pdb的参数将覆盖cdb的参数.不再参考cdb的参数值.而且此pdb的参数是存放在数据字典中.

下面我们看一个实例:

当前cdb的参数open_cursor为600,即上面参数文件中指定的:

SQL>conn / as sysdba

Connected.

SQL>show con_name

CON_NAME

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

CDB$ROOT

SQL>show parameter open_cursor

NAME				     TYPE	 VALUE

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

open_cursors			     integer	 600

SQL>

而此时pdb2的参数也为600:

SQL>alter session set container=pdb2;

Session altered.

SQL>show con_name

CON_NAME

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

PDB2

SQL>show parameter open_cursor;

NAME				     TYPE	 VALUE

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

open_cursors			     integer	 600

此时我们修改cdb的参数:

SQL>conn / as sysdba            

Connected.

SQL>show con_name

CON_NAME

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

CDB$ROOT

SQL>alter system set open_cursors=500;

System altered.

SQL>show parameter open_cursors

NAME				     TYPE	 VALUE

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

open_cursors			     integer	 500

SQL>alter session set container=pdb2;

Session altered.

SQL>show con_name

CON_NAME

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

PDB2

SQL>show parameter open_cursor;

NAME				     TYPE	 VALUE

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

open_cursors			     integer	 500

我们发现pdb的参数也跟着修改了,说明pdb的参数是有cdb参数控制的.

继续,我们手工修改pdb的参数:

SQL>show con_name

CON_NAME

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

PDB2

SQL>alter system set open_cursors=1000;

System altered.

SQL>conn / as sysdba

Connected.

SQL>show parameter open_cursors

NAME				     TYPE	 VALUE

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

open_cursors			     integer	 500

SQL>alter system set open_cursors=800;

System altered.

SQL>show con_name

CON_NAME

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

CDB$ROOT

SQL>alter session set container=pdb2;

Session altered.

SQL>show parameter open_cursors

NAME				     TYPE	 VALUE

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

open_cursors			     integer	 1000

我们发现手工修改pdb的参数之后,那么此参数就不受cdb参数控制了.再修改cdb的参数也无法修改pdb的参数值.

可以通过查看数据字典pdb_spfile$来查看pdb指定的参数:

SQL>select a.name,a.dbid,b.pdb_uid,b.name,b.value$ from v$pdbs a ,pdb_spfile$ b where a.dbid=b.pdb_uid and a.name='PDB2'

SQL>/

NAME				     DBID    PDB_UID NAME									      VALUE$

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

PDB2			       2158045800 2158045800 db_securefile								      'PREFERRED'

PDB2			       2158045800 2158045800 open_cursors								      1000