Oracle DataGuard奇怪的ORA-16494错误

Oracle数据库DataGuard数据无法同步，主库查询v$archive_dest出现ORA-16494错误。
数据库版本Oracle 12.1.0.2.0：

SQL> select * from v$version;BANNER
--------------------------------------------------------------------------------CON_ID
----------
Oracle Database 12c Enterprise Edition Release 12.1.0.2.0 - 64bit Production0PL/SQL Release 12.1.0.2.0 - Production0CORE    12.1.0.2.0      Production0BANNER
--------------------------------------------------------------------------------CON_ID
----------
TNS for 64-bit Windows: Version 12.1.0.2.0 - Production0NLSRTL Version 12.1.0.2.0 - Production0

检查主库DG参数：

SQL> show parameter log_archive_configNAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
log_archive_config                   string      DG_CONFIG=(orcl,orcladg)
SQL>
SQL> show parameter log_archive_dest_2NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
log_archive_dest_2                   string      SERVICE=orcladg LGWR ASYNC VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLE) DB_UNIQUE_NAME=orcladg
log_archive_dest_20                  string
log_archive_dest_21                  string
log_archive_dest_22                  string
log_archive_dest_23                  string
log_archive_dest_24                  string
log_archive_dest_25                  string
log_archive_dest_26                  string
log_archive_dest_27                  stringNAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
log_archive_dest_28                  string
log_archive_dest_29                  string
SQL> show parameter service_namesNAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
service_names                        string      orcl
SQL> show parameter uniqueNAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
db_unique_name                       string      orcl

检查备库参数：

SQL> show parameter log_archive_configNAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
log_archive_config                   string      DG_CONFIG=(orcl,orcladg)
SQL> show parameter log_archive_dest_2NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
log_archive_dest_2                   string      SERVICE=orcl LGWR ASYNC VALID_FOR=(ONLINE_LOGFILES,PRIMARY_ROLE) DB_UNIQUE_NAME=orcl
log_archive_dest_20                  string
log_archive_dest_21                  string
log_archive_dest_22                  string
log_archive_dest_23                  string
log_archive_dest_24                  string
log_archive_dest_25                  string
log_archive_dest_26                  string
log_archive_dest_27                  stringNAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
log_archive_dest_28                  string
log_archive_dest_29                  string
SQL> show parameter service_namesNAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
service_names                        string      pdborcl
SQL> show parameter uniqueNAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
db_unique_name                       string      orcladg

检查主备库之间的网络连通性
主库：

C:\Users\Administrator>tnsping orclTNS Ping Utility for 64-bit Windows: Version 12.1.0.2.0 - Production on 08-5月 -2023 22:42:27Copyright (c) 1997, 2014, Oracle.  All rights reserved.已使用的参数文件:
C:\app\pdborcl\product\12.1.0\dbhome_1\network\admin\sqlnet.ora已使用 TNSNAMES 适配器来解析别名
尝试连接 (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = WIN-VJ841V9N3PU)(PORT = 1521))) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME =
OK (20 毫秒)C:\Users\Administrator>tnsping orcladgTNS Ping Utility for 64-bit Windows: Version 12.1.0.2.0 - Production on 08-5月 -2023 22:42:39Copyright (c) 1997, 2014, Oracle.  All rights reserved.已使用的参数文件:
C:\app\pdborcl\product\12.1.0\dbhome_1\network\admin\sqlnet.ora已使用 TNSNAMES 适配器来解析别名
尝试连接 (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = 172.16.188.201)(PORT = 1521)) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = pdborcl)))
OK (20 毫秒)

备库：

C:\Users\Administrator>tnsping orclTNS Ping Utility for 64-bit Windows: Version 12.1.0.2.0 - Production on 08-5月 -2023 22:42:27Copyright (c) 1997, 2014, Oracle.  All rights reserved.已使用的参数文件:
C:\app\pdborcl\product\12.1.0\dbhome_1\network\admin\sqlnet.ora已使用 TNSNAMES 适配器来解析别名
尝试连接 (DESCRIPTION = (ADDRESS_LIST = (ADDRESS = (PROTOCOL = TCP)(HOST = WIN-VJ841V9N3PU)(PORT = 1521))) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME =
OK (20 毫秒)C:\Users\Administrator>tnsping orcladgTNS Ping Utility for 64-bit Windows: Version 12.1.0.2.0 - Production on 08-5月 -2023 22:42:39Copyright (c) 1997, 2014, Oracle.  All rights reserved.已使用的参数文件:
C:\app\pdborcl\product\12.1.0\dbhome_1\network\admin\sqlnet.ora已使用 TNSNAMES 适配器来解析别名
尝试连接 (DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = 172.16.188.201)(PORT = 1521)) (CONNECT_DATA = (SERVER = DEDICATED) (SERVICE_NAME = pdborcl)))
OK (20 毫秒)

主备库之间网络是畅通的。
主库切换日志，查询v$archive_dest：

SQL> alter system switch logfile;系统已更改。

出现ORA-16494错误，该错误在网上找不到，而且MOS上也没有相关的记载。
再次检查备库，会不会是PDB模式的，而且有名为PDBORCL的PDB，导致主库通过tns直接连到了PDB中。
备库查询：

SQL> select con_id,name,open_mode from v$pdbs;CON_ID NAME                           OPEN_MODE
---------- ------------------------------ ----------2 PDB$SEED                       MOUNTED3 PDBORCL                        MOUNTED

果然有个叫PDBORCL的PDB。
查看数据库的数据库名：

SQL> select name,open_mode,database_role from v$database;NAME      OPEN_MODE            DATABASE_ROLE
--------- -------------------- ----------------
ORCL      MOUNTED              PHYSICAL STANDBY

所以，如果想连到CDB中，应该将service_names指定为orcl，由于是备库，可设置为rzorcl或orclstd等，方便识别，但是一定要与PDBORCL不同名。
修改备库service_names

SQL> alter system set service_names='rzorcl';

在修改主库和备库中tnsnames.ora文件中备库连接串中SERVICE=RZORCL。
再次尝试切换日志，错误消失。

系统已更改。SQL>
SQL>
SQL>
SQL> select error from v$archive_dest;ERROR
-----------------------------------------------------------------ERROR
-----------------------------------------------------------------ERROR
-----------------------------------------------------------------已选择 31 行。SQL>

再次查看备库日志接收情况：

SQL> select process,sequence#,block# from v$managed_standby;PROCESS    SEQUENCE#     BLOCK#
--------- ---------- ----------
ARCH          103988      43008
ARCH               0          0
ARCH          103987       4096
ARCH          103989      40960
MRP0          103990      29955
RFS                0          0
RFS           103990      29955
RFS                0          0
RFS                0          09 rows selected.

备库日志接收正常，问题解决。