1、使用using current logfile啟動日誌應用程序
Completed: alter database recover managed standby database using current logfile disconnect from session
Fri Aug 17 11:12:25 2018
RFS[2]: Selected log 4 for thread 1 sequence 242 dbid 1580843042 branch 984338351
Fri Aug 17 11:12:25 2018
Archived Log entry 136 added for thread 1 sequence 241 ID 0x6eb57733 dest 1:
Fri Aug 17 11:12:26 2018
Media Recovery Waiting for thread 1 sequence 242 (in transit)
Recovery of Online Redo Log: Thread 1 Group 4 Seq 242 Reading mem 0
  Mem# 0: Z:\ORACLE\ORADATA\HISDG\STDREDO04.LOG
RFS[2]: Selected log 5 for thread 1 sequence 243 dbid 1580843042 branch 984338351
Fri Aug 17 11:12:27 2018
Archived Log entry 137 added for thread 1 sequence 242 ID 0x6eb57733 dest 1:
Media Recovery Waiting for thread 1 sequence 243 (in transit)
Recovery of Online Redo Log: Thread 1 Group 5 Seq 243 Reading mem 0
  Mem# 0: Z:\ORACLE\ORADATA\HISDG\STDREDO05.LOG
Fri Aug 17 11:12:48 2018
RFS[2]: Selected log 4 for thread 1 sequence 244 dbid 1580843042 branch 984338351
Fri Aug 17 11:12:48 2018
Archived Log entry 138 added for thread 1 sequence 243 ID 0x6eb57733 dest 1:
Fri Aug 17 11:12:48 2018
Media Recovery Waiting for thread 1 sequence 244 (in transit)
Recovery of Online Redo Log: Thread 1 Group 4 Seq 244 Reading mem 0
  Mem# 0: Z:\ORACLE\ORADATA\HISDG\STDREDO04.LOG
RFS[2]: Selected log 5 for thread 1 sequence 245 dbid 1580843042 branch 984338351
Fri Aug 17 11:12:49 2018
Archived Log entry 139 added for thread 1 sequence 244 ID 0x6eb57733 dest 1:
Media Recovery Waiting for thread 1 sequence 245 (in transit)
Recovery of Online Redo Log: Thread 1 Group 5 Seq 245 Reading mem 0
  Mem# 0: Z:\ORACLE\ORADATA\HISDG\STDREDO05.LOG               ---應用的for standby redo

  
此時為實時應用模式，查詢gv$dataguard_stats基本無延遲資訊。
  
  
2、不使用using current logfile或者沒有配置目標端for standby redo的情況下啟動日誌應用程序  
Completed: alter database recover managed standby database disconnect from session
Thu Aug 16 08:21:48 2018
Archived Log entry 7215 added for thread 2 sequence 15681 rlc 727161533 ID 0x40264971 dest 2:
RFS[1]: No standby redo logfiles available for thread 2 
RFS[1]: Opened log for thread 2 sequence 15682 dbid 842685821 branch 727161533
Thu Aug 16 08:46:34 2018
Archived Log entry 7216 added for thread 1 sequence 13484 rlc 727161533 ID 0x40264971 dest 2:
RFS[2]: No standby redo logfiles available for thread 1 
RFS[2]: Opened log for thread 1 sequence 13485 dbid 842685821 branch 727161533
Thu Aug 16 08:46:34 2018
Media Recovery Log /arch/hisdg12/srl/1_13484_727161533.dbf     --應用的歸檔日誌
Media Recovery Log /arch/hisdg12/srl/2_15681_727161533.dbf

此時查詢gv$dataguard_stats可能會出現如下較大延遲資訊：
SQL>select * from gv$dataguard_stats;
INST_ID NAME                   VALUE            UNIT                         TIME_COMPUTED       DATUM_TIME
------- ---------------------- ---------------- ---------------------------- ------------------- -------------------
      1 transport lag          +00 02:32:31

    day(2) to second(0) interval 08/16/2018 14:26:46 08/16/2018 14:26:18
      1 apply lag              +00 02:32:31     day(2) to second(0) interval 08/16/2018 14:26:46 08/16/2018 14:26:18
      1 apply finish time      +00 00:00:03.217 day(2) to second(3) interval 08/16/2018 14:26:46
      1 estimated startup time 14               second                       08/16/2018 14:26:46