我异地DG,本想应用归档不想实时同步alter database recover managed standby database disconnect from session;
可是怎么查看还是实时同步日志呢

你这样检查是不对的。
通过恢复模式才能最终确认备库的应用模式,例如如下查询种 RECOVERY_MODE 显示 MANAGED REAL TIME APPLY,才是实时应用模式:
SQL> col dest_name for a30
SQL> select DEST_ID,dest_name,status,type,srl,recovery_mode from v$archive_dest_status where dest_id=1;
DEST_ID DEST_NAME STATUS TYPE SRL RECOVERY_MODE
---------- ------------------------------ --------- -------------- --- -----------------------
1 LOG_ARCHIVE_DEST_1 VALID LOCAL NO MANAGED REAL TIME APPLY
实时应用模式需要使用当前日志文件启用:
SQL>ALTER DATABASE RECOVER MANAGED STANDBY DATABASE USING CURRENT LOGFILE;


本想应用归档不想实时同步alter database recover managed standby database disconnect from session;


using current logfile语句在12c中已经废弃,RECOVER MANAGED STANDBY DATABASE DISCONNECT FROM SESSION;默认就是用的current logfile,也就是加不加current logfile都是实时应用在线日志。
如果需要应用归档,需要加using archived log,既:
alter database recover managed standby database using archived logfile disconnect from session;复制


