模拟

主库的归档日志在没有传输到从库就被删除

1.主库关闭日志传输
PRIMARY_SQL> Alter system set log_archive_dest_state_2=defer scope =both;
2.切换日志，创建两个归档日志
PRIMARY_SQL > alter system switch logfile;
System altered.
PRIMARY_SQL > alter system switch logfile;
System altered.
3.主库移除刚刚生成的两个归档日志
4.主库开启日志传输
PRIMARY_SQL > Alter system set log_archive_dest_state_2=enable scope=both;

因为主库删除了归档日志，现在从库无法继续同步了。

修复

获取主库和从库的SCN

首先获取主库和从库的SCN

1. 主库当前的scn

PRIMARY_SQL > select current_scn from v$database;
CURRENT_SCN
-----------
2791422

2. 从库当前的scn​

STANDBY_SQL > select current_scn from v$database;
CURRENT_SCN
-----------
2791087 -

恢复从库，需要从SCN：2791087开始。

3.从库关闭日志应用进程

STANDBY_SQL > alter database recover managed standby database cancel;

4.关闭从库

STANDBY_SQL > shutdown immediate;

5.主库做增量备份，从上面我们查出的SCN开始备份​

RMAN> run {
allocate channel c1 type disk format '/home/oracle/abce/rman_bkup%U.rmb';
backup incremental from scn 2791087 database;
}

6.为从库创建一个新的standby控制文件(在primary端创建)​

PRIMARY_SQL > alter database create standby controlfile as
'/home/oracle/abce/control02.ctl';

7.将rman备份和standby控制文件拷贝到从库

在从库，拷贝到/home/oracle/abce/

8.将从库启动到nomount状态

STANDBY_SQL > startup nomount;

9.找到standby端的控制文件​

STANDBY_SQL > show parameter control_files
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
control_files string /u04/TEST/oradata/control02.ctl

10.使用主库上面创建的standby控制文件替换该控制文件

cp /home/oracle/abce/control02.ctl /u04/TEST/oradata/control02.ctl

11.将从库启动到mount状态

STANDBY_SQL > alter database mount standby database;

12.注册rman备份文件

STANDBY]$ rman target /
Recovery Manager: Release 11.2.0.2.0 - Production on Fri Sep 20 09:14:08 2013
Copyright (c) 1982, 2009, Oracle and/or its affiliates. All rights reserved.
connected to target database: TESTER (DBID=3502897675, not open)
RMAN> catalog start with '/home/oracle/abce';
using target database control file instead of recovery catalog
searching for all files that match the pattern /home/oracle/abce
List of Files Unknown to the Database
=====================================
File Name: /home/oracle/abce/control02.ctl
Do you really want to catalog the above files (enter YES or NO)? yes
cataloging files...
cataloging done
List of Cataloged Files
=======================
File Name: /home/oracle/abce/control02.ctl

13.恢复从库​

RMAN> recover database;
Starting recover at 20-SEP-13
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=76 device type=DISK
channel ORA_DISK_1: starting incremental datafile backup set restore
channel ORA_DISK_1: specifying datafile(s) to restore from backup set
destination for restore of datafile 00001: /u04/TEST/oradata/system.dbf
destination for restore of datafile 00002: /u04/TEST/oradata/sysaux.dbf9
destination for restore of datafile 00003: /u04/TEST/oradata/undotbs1.dbf
destination for restore of datafile 00004: /u04/TEST/oradata/user01.dbf
channel ORA_DISK_1: reading from backup piece /home/oracle/abce/rman_bkup0aokac2j_1_1.rmb
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of recover command at 09/20/2013 09:16:41
ORA-19870: error while restoring backup piece /home/oracle/abce/rman_bkup0aokac2j_1_1.rmb
ORA-19573: cannot obtain exclusive enqueue for datafile 4

如果发生如上错误，将recovery过程停止。

STANDBY_SQL > alter database recover managed standby database cancel;
Database altered.
Again follow the same process i.e recovering the database
RMAN> recover database;
Starting recover at 20-SEP-13
using channel ORA_DISK_1
channel ORA_DISK_1: starting incremental datafile backup set restore
channel ORA_DISK_1: specifying datafile(s) to restore from backup set
destination for restore of datafile 00001: /u04/TEST/oradata/system.dbf
destination for restore of datafile 00002: /u04/TEST/oradata/sysaux.dbf
destination for restore of datafile 00003: /u04/TEST/oradata/undotbs1.dbf
destination for restore of datafile 00004: /u04/TEST/oradata/user01.dbf
channel ORA_DISK_1: reading from backup piece /home/oracle/abce/rman_bkup0aokac2j_1_1.rmb
channel ORA_DISK_1: piece handle=/home/oracle/abce/rman_bkup0aokac2j_1_1.rmb tag=TAG20130920T080539
channel ORA_DISK_1: restored backup piece 1
channel ORA_DISK_1: restore complete, elapsed time: 00:00:01
starting media recovery
archived log for thread 1 with sequence 250 is already on disk as file
/u04/TEST/oradata/REDO_STDBY/1_250_824551947.arc
archived log file name=/u04/TEST/oradata/REDO_STDBY/1_250_824551947.arc thread=1 sequence=250
unable to find archived log
archived log thread=1 sequence=251
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================10
RMAN-03002: failure of recover command at 09/20/2013 09:28:04
RMAN-06054: media recovery requesting unknown archived log for thread 1 with sequence 251 and starting SCN of
2796410

如果发生这个错误，属于预料内的。因为我们已经到了归档日志的末尾。sequence# 251的日志还没有生成。

启动MRP

STANDBY_SQL > alter database recover managed standby database disconnect from session;

至此，从库已经和主库是同步的了。

可以检查一下：​

1. [Primary] Find current_scn from primary.
PRIMARY_SQL > select current_scn from v$database;
CURRENT_SCN
-----------
2791422
2. [Standby] Find current_scn from standby.
STANDBY_SQL > select current_scn from v$database;
CURRENT_SCN
-----------
279142211

检查从库的进程状态​

STANDBY_SQL > select sequence#,process,status from v$managed_standby;
SEQUENCE# PROCESS STATUS
---------- --------- ------------
258 ARCH CLOSING
0 ARCH CONNECTED
259 RFS IDLE
259 MRP0 WAIT_FOR_LOG

RFS IDLE

主库切换日志，看从库是否接受和应用​

PRIMARY_SQL > alter system switch logfile;
System altered.
PRIMARY_SQL > archive log list
Database log mode Archive Mode
Automatic archival Enabled
Archive destination /u03/TEST/oradata/REDO_STDBY/
Oldest online log sequence 257
Next log sequence to archive 259
Current log sequence 259
STANDBY_SQL > archive log list
Database log mode Archive Mode
Automatic archival Enabled
Archive destination /u04/TEST/oradata/REDO_STDBY/
Oldest online log sequence 258
Next log sequence to archive 0
Current log sequence 259

https://dbaclass.com/article/how-to-recover-standby-database-when-archive-logs-are-missing-in-primary/