文档课题：实现oracle 19c pdb在cdb重启后，自动开启相应pdb.
[oracle@dbserver ~]$ sql / as sysdba

SQLcl: Release 19.1 Production on Wed Nov 02 14:26:19 2022

Copyright (c) 1982, 2022, Oracle.  All rights reserved.

Connected to:
Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.12.0.0.0


SQL> show pdbs

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

SQL> alter pluggable database orclpdb open;

Pluggable database altered.

说明：如上所示，每次cdb开启后，对应的pdb在均mounted阶段，都需要重新open pdb.
如何解决这个问题呢？以下便是解决此问题操作过程.
SQL> select con_name,state from cdb_pdb_saved_states;
no rows selected
SQL> alter pluggable database all save state;

Pluggable database altered.
注意：若是集群环境，每个节点都要保存状态.
SQL> col con_name for a15
SQL> select con_name,state from cdb_pdb_saved_states;

CON_NAME        STATE         
--------------- --------------
ORCLPDB         OPEN          
SQL> col INSTANCE_NAME for a15
SQL> select instance_name,con_name,state from cdb_pdb_saved_states order by 1,2;

INSTANCE_NAME   CON_NAME        STATE         
--------------- --------------- --------------
orclcdb         ORCLPDB         OPEN          

SQL> select name from v$database;

NAME     
---------
ORCLCDB  
重启数据库确认.
SQL> startup force;

Total System Global Area   2415918600 bytes      
Fixed Size                    9137672 bytes      
Variable Size               989855744 bytes      
Database Buffers           1409286144 bytes      
Redo Buffers                  7639040 bytes      
Database mounted.
Database opened.
SQL> show pdbs;

    CON_ID CON_NAME                       OPEN MODE  RESTRICTED
---------- ------------------------------ ---------- ----------
         2 PDB$SEED                       READ ONLY  NO        
         3 ORCLPDB                        READ WRITE NO        
说明：如上所示，cdb重启后对应的pdb自动read write.