下面如果启动程序，进行更新。

SQL> alter database recover managed standby database using current logfile disconnect from session;

Database altered

在日志中看到应用日志过程：

Mon Oct 19 11:23:53 2015

alter database recover managed standby database using current logfile disconnect from session

Attempt to start background Managed Standby Recovery process (vlifesb)

Mon Oct 19 11:23:53 2015

MRP0 started with pid=28, OS id=15602?

MRP0: Background Managed Standby Recovery process started (vlifesb)

?started logmerger process

Mon Oct 19 11:23:58 2015

Managed Standby Recovery starting Real Time Apply

Parallel Media Recovery started with 4 slaves

Waiting for all non-current ORLs to be archived...

All non-current ORLs have been archived.

Media Recovery Log /u01/app/oracle/fast_recovery_area/VLIFESB/archivelog/2015_10_19/o1_mf_1_39_c28rgoqb_.arc

Media Recovery Log /u01/app/oracle/fast_recovery_area/VLIFESB/archivelog/2015_10_19/o1_mf_1_40_c28rgpq1_.arc

Media Recovery Log /u01/app/oracle/fast_recovery_area/VLIFESB/archivelog/2015_10_19/o1_mf_1_41_c28rgtl2_.arc

Media Recovery Waiting for thread 1 sequence 42 (in transit)

Recovery of Online Redo Log: Thread 1 Group 4 Seq 42 Reading mem 0

? Mem# 0: /u01/app/oracle/oradata/VLIFESB/onlinelog/o1_mf_4_c265gc9q_.log

? Mem# 1: /u01/app/oracle/fast_recovery_area/VLIFESB/onlinelog/o1_mf_4_c265gcfk_.log

Completed: alter database recover managed standby database using current logfile disconnect from session

这个过程中，进行standby recovery操作，先从归档日志中找到没有apply的进行应用。之后应用standby redo log。

此时，apply成功，能够追上Primary。

SQL> select group#, dbid, sequence#, used, archived, status from v$standby_log;

? ? GROUP# DBID? ? ? ? ? ? ? ? ? SEQUENCE#? ? ? USED ARCHIVED STATUS

---------- -------------------- ---------- ---------- -------- ----------

? ? ? ? 4 4207470439? ? ? ? ? ? ? ? ? 42? ? 107520 YES? ? ? ACTIVE

? ? ? ? 5 UNASSIGNED? ? ? ? ? ? ? ? ? ? 0? ? ? ? ? 0 NO? ? ? UNASSIGNED

? ? ? ? 6 UNASSIGNED? ? ? ? ? ? ? ? ? ? 0? ? ? ? ? 0 YES? ? ? UNASSIGNED

SQL> select recid, sequence#, ARCHIVED, APPLIED, DELETED from v$archived_log;

? ? RECID? SEQUENCE# ARCHIVED APPLIED? DELETED

---------- ---------- -------- --------- -------

（篇幅原因，有省略……）

? ? ? ? 15? ? ? ? 36 YES? ? ? YES? ? ? NO

? ? ? ? 16? ? ? ? 37 YES? ? ? YES? ? ? NO

? ? ? ? 17? ? ? ? 38 YES? ? ? YES? ? ? NO

? ? ? ? 18? ? ? ? 39 YES? ? ? YES? ? ? NO

? ? ? ? 19? ? ? ? 40 YES? ? ? YES? ? ? NO

? ? ? ? 20? ? ? ? 41 YES? ? ? IN-MEMORY NO

20 rows selected

4、结论

Standby Redo Log是Standby数据库的online redo log。对于Oracle而言，online redo log和standby redo log都反映了当前最近的一个日志对象。针对数据库角色的不同，应用的操作各走两支。