rac模式下pdb修改undo表空间

仅演示了其中一个实例，另一个实例重复操作即可。

---查看当前undo表空间

SQL> alter session set container=ncdb;
SQL> show pdbs;

    CON_ID CON_NAME                       OPEN MODE  RESTRICTED
---------- ------------------------------ ---------- ----------
         3 NCDB                           READ WRITE NO
SQL> show parameter undo;

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
_highthreshold_undoretention         integer     31536000
temp_undo_enabled                    boolean     FALSE
undo_management                      string      AUTO
undo_retention                       integer     900
undo_tablespace                      string      UNDOTBS2B

---以限制模式打开pdb

SQL> conn / as sysdba

SQL> alter pluggable database ncdb close;

SQL> alter pluggable database ncdb open restricted;

---创建新的undo

SQL> alter session set container=ncdb;

SQL> create undo tablespace undotbs1 datafile size 20G autoextend on maxsize 30G;

SQL>  show parameter instance_name

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
instance_name                        string      zjcdba2

SQL> alter system set undo_tablespace=undotbs1 sid='zjcdba2' scope=both;

SQL> shut immediate;

SQL> show pdbs;

    CON_ID CON_NAME                       OPEN MODE  RESTRICTED
---------- ------------------------------ ---------- ----------
         3 NCDB                           MOUNTED

---重启生效

SQL> startup

SQL> show pdbs;

    CON_ID CON_NAME                       OPEN MODE  RESTRICTED
---------- ------------------------------ ---------- ----------
         3 NCDB                           READ WRITE NO
SQL> show parameter undo;

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
_highthreshold_undoretention         integer     31536000
temp_undo_enabled                    boolean     FALSE
undo_management                      string      AUTO
undo_retention                       integer     900
undo_tablespace                      string      UNDOTBS1


参考：
How to Switch/Recreate Undo Tablespace at PDB Level (文档 ID 2560841.1)