通过SYS_CONTEXT命令来查看,
col con_id format a10
col con_name format a20
select sys_context('userenv','con_id') as con_id,sys_context('userenv','con_name') as
con_name from dual;
通过show 命令
[oracle@oracle-db-19c ~]$ sqlplus / as sysdba SQL*Plus: Release 19.0.0.0.0 - Production on Wed Nov 30 11:07:06 2022 Version 19.3.0.0.0 Copyright (c) 1982, 2019, Oracle. All rights reserved. Connected to: Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production Version 19.3.0.0.0 SQL> col con_id format a10 SQL> col con_name format a20 SQL> select sys_context("userenv","con_id") as con_id,sys_context("userenv","con_name") as con_name from dual; CON_ID CON_NAME ---------- -------------------- 1 CDB$ROOT SQL> SQL> show con_name; CON_NAME ------------------------------ CDB$ROOT SQL> SQL> show pdbs; CON_ID CON_NAME OPEN MODE RESTRICTED ---------- ------------------------------ ---------- ---------- 2 PDB$SEED READ ONLY NO 3 PDB1 READ WRITE NO 4 PDB2 MOUNTED 5 CNDBAPDB MOUNTED 6 CNDBAPDB3 MOUNTED 7 CNDBAPDB2 MOUNTED 8 CNDBAPDB4_FRESH READ ONLY NO SQL> alter session set container=PDB1; Session altered. SQL> show user; USER is "SYS" SQL> show con_name; CON_NAME ------------------------------ PDB1 SQL>
[oracle@oracle-db-19c ~]$ [oracle@oracle-db-19c ~]$ sqlplus / as sysdba SQL*Plus: Release 19.0.0.0.0 - Production on Wed Nov 30 11:26:54 2022 Version 19.3.0.0.0 Copyright (c) 1982, 2019, Oracle. All rights reserved. Connected to: Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production Version 19.3.0.0.0 SQL> col name for a20 SQL> select con_id,name,ispdb_modifiable from v$system_parameter where name="open_cursors"; CON_ID NAME ISPDB ---------- -------------------- ----- 0 open_cursors TRUE SQL> set linesize 200 SQL> show parameter open_cursors; NAME TYPE VALUE ------------------------------------ ----------- ------------------------------ open_cursors integer 300 SQL> alter system set open_cursors = 301; System altered. SQL> show parameter open_cursors; NAME TYPE VALUE ------------------------------------ ----------- ------------------------------ open_cursors integer 301 SQL> alter session set container=PDB1; Session altered. SQL> show parameter open_cursors; NAME TYPE VALUE ------------------------------------ ----------- ------------------------------ open_cursors integer 301 SQL>
(1) 修改CDB。当公共用户连接的是CDB root时,通过ALTER DATABASE 命令执行如下语句会修改整个CDB.
startup/recovery/logfile/controlfile/standbydatabase/instance/security/RENAME/GLOBAL_NAME/ENABLE LOCK CHANGE TRACKING/DISABLE LOCK CHANGE TRACKING
(2) 只修改CDB root 。当公共用户连接的是CDB root时,通过ALTER DATABASE 命令执行如下语句只修改CDB root
datafile/DEFAULT EDITION/DEFAULT TABLESPACE/ DEFAULT TEMPORARY TABLESPACE
(3) 修改一个或多个PDB。公共用户连接到CDB root时,可以通过ALTER PLUGGABLE DATABASE 语句修改PDB的打开状态(MOUNT/READ ONLY/READ WRITE),以及保存/忽略PDB的打开状态。
[oracle@oracle-db-19c ~]$ sqlplus / as sysdba SQL*Plus: Release 19.0.0.0.0 - Production on Wed Nov 30 13:39:46 2022 Version 19.3.0.0.0 Copyright (c) 1982, 2019, Oracle. All rights reserved. Connected to: Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production Version 19.3.0.0.0 SQL> show user; USER is "SYS" SQL> show con_name; CON_NAME ------------------------------ CDB$ROOT SQL> col property_name for a30; SQL> col property_value for a20; SQL> select property_name,property_value from database_properties where property_name="LOCAL_UNDO_ENABLED"; PROPERTY_NAME PROPERTY_VALUE ------------------------------ -------------------- LOCAL_UNDO_ENABLED TRUE SQL>
TRUE代表本地UNDO模式,FLASE代表共享UNDO模式。
(2)共享UNDO模式转换为本地UNDO模式的步骤如下:
关闭CDB,代码如下
shutdown immediate;
以UPGRADE方式启动CDB,代码如下:
STARTUP UPGRADE;
确认当前容器是CDB root,代码如下:
show con_name;
启动本地UNDO,代码
ALTER DATABASE LOCAL UNDO ON;
重启 CDB,正常打开,
SHUTDOWN IMMEDIATE;STARTUP;
(3) 本地UNDO模式转换为共享UNDO模式的步骤如下:
关闭CDB
shutdown immediate
以UPGRADE方式启动CDB,
STARTUP UPGRADE;
确认当前容器是CDB root,
SHOW CON_NAME
禁用本地UNDO
ALTER DATABASE LOCAL UNDO OFF
重启CDB,正常打开,
SHUTDOWN IMMEDIATE;STARTUP;
# CDB SQL> SQL> show con_name; CON_NAME ------------------------------ CDB$ROOT SQL> show parameter spfile; NAME TYPE VALUE ------------------------------------ ----------- ------------------------------ spfile string /u01/app/oracle/product/19.3.0 /dbhome_1/dbs/spfilecdb1.ora SQL> SQL> alter session set container=PDB1; Session altered. SQL> show parameter spfile; NAME TYPE VALUE ------------------------------------ ----------- ------------------------------ spfile string /u01/app/oracle/product/19.3.0 /dbhome_1/dbs/spfilecdb1.ora SQL> alter session set container=cdb$root; Session altered. SQL>
Fleet就是一个逻辑的CDB集合。其中,Lead CDB 是CDB Fleet中用于监控和管理其它CDB的。
在CDB Fleet中,可以通过以下方式来访问CDB和PDB中的数据:
1.设置Lead CDB ,通过以下命令启动该特性:
# 启动 LEAD CDB SQL> SQL> alter database set lead_cdb = true; Database altered. SQL> select property_value from database_properties where property_name="LEAD_CDB"; PROPERTY_VALUE -------------------- TRUE SQL>
管理PDB和管理普通的Non-CDB一样,可以管理表空间、数据文件、临时文件和用户对象等。
在系统级别修改PDB
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