SQL>  ALTER DATABASE ADD SUPPLEMENTAL LOG DATA (PRIMARY KEY, UNIQUE INDEX) COLUMNS;

If you do not do this, then any logical standby that is also in the same Data Guard configuration will be unusable if a switchover or failover is performed to one of the physical standby databases. If a switchover or failover has already occurred and supplemental logging was not enabled, then you must recreate all logical standby databases

第三步：在备库告诉mrp继续应用redo，达到字典构建时的scn；

SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup mount;
ORACLE instance started.

Total System Global Area  313159680 bytes
Fixed Size                  2252824 bytes
Variable Size             171970536 bytes
Database Buffers          134217728 bytes
Redo Buffers                4718592 bytes
Database mounted.

SQL> alter database recover to logical standby Amy;

Database altered.

这时我们修改几个地方，首先是db_name;

SQL> alter system set db_name=Amy scope=spfile;

System altered.

SQL> exit
Disconnected from Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options

另外还有log_archive_dest_n 参数配置：

SQL> show parameter log_archive_dest_1

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
log_archive_dest_1                   string      location=USE_DB_RECOVERY_FILE_
                                                 DEST valid_for=(all_logfiles,a
                                                 ll_roles)
log_archive_dest_10                  string
log_archive_dest_11                  string
log_archive_dest_12                  string
log_archive_dest_13                  string
log_archive_dest_14                  string
log_archive_dest_15                  string
log_archive_dest_16                  string
log_archive_dest_17                  string

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
log_archive_dest_18                  string
log_archive_dest_19                  string
SQL> show parameter log_archive_dest_2

NAME                                 TYPE        VALUE
------------------------------------ ----------- ------------------------------
log_archive_dest_2                   string      service=dg1 lgwr sync valid_fo
                                                 r=(online_logfiles,primary_rol
                                                 e) db_unique_name=dg1
log_archive_dest_20                  string

这里需要说明第一个log_archive_dest_1 为什么是all_logfiles呢？因为我们是创建的逻辑备库，逻辑备库除了维护主库的对象外，还可以自己进行其他对象的修改操作那么这些对象的redo，是需要归档的，逻辑备库是一个真实数据库啊，另外如果不指定快速闪回区，那么应该在加一个log_archive_dest_3,将日志分开，另外如果是快速闪回区，可以省略valid_for,因为默认就是all_logfiles,all_roles。
另外要注意：如果逻辑备库和主库在一个相同的数据存储管理上，那么需要使用dbms_logstdby.skip去跳过alter tablespace dml的操作，不然可能产生误修改主库的表空间问题。
第四步：完成逻辑dg的创建：