Oracle 无关紧要的RMAN-06054

RMAN>  backup incremental level=0 database format '/home/oracle/rman/%U';

SYS@prod>create table test as  select * from dba_objects;

Table created.

SYS@prod>insert into test select * from test;

86959 rows created.

SYS@prod>/

173918 rows created.

SYS@prod>/

347836 rows created.

SYS@prod>insert into test select * from test;

695672 rows created.

SYS@prod>commit;

Commit complete

SYS@prod>select count(*) from test;

  COUNT(*)

----------

   1391344

SYS@prod>select group#,status from v$log;

    GROUP# STATUS

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

 1 ACTIVE

 2 ACTIVE

 3 CURRENT

查看当前控制文件头部和数据文件头部 SCN号：

SYS@prod>select checkpoint_change# from v$datafile;

CHECKPOINT_CHANGE#

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

   1198910

   1198910

   1198910

   1198910

   1198910

SYS@prod>select checkpoint_change# from v$datafile_header;

CHECKPOINT_CHANGE#

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

   1198984

   1198984

   1198984

   1198984

   1198984

进行一次增量备份：

RMAN> backup incremental level=1 database format '/home/oracle/rman/%U';

然后再次查看SCN：

SYS@prod>select checkpoint_change# from v$datafile;

CHECKPOINT_CHANGE#

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

   1199201

   1199201

   1199201

   1199201

   1199201

SYS@prod>select checkpoint_change# from v$datafile;

CHECKPOINT_CHANGE#

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

   1199201

   1199201

   1199201

   1199201

   1199201

SYS@prod>select group#,status from v$log;

    GROUP# STATUS

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

 1 INACTIVE

 2 INACTIVE

 3 CURRENT

可以看出：SCN 号同步刷新，日志组状态改变， RMAN 备份与热备份性质一样，都会在备份前做一个完全检查点，将脏块刷新回数据文件。

此时删除全部的文件进行恢复：

[oracle@service1 prod]$ ls

control01.ctl  redo01.log  redo03.log    system01.dbf  undotbs01.dbf

example01.dbf  redo02.log  sysaux01.dbf  temp01.dbf    users01.dbf

[oracle@service1 prod]$ rm -rf  *

[oracle@service1 ~]$ sqlplus / as sysdba

SYS@prod>shutdown abort;

SYS@prod>startup nomount;

[oracle@service1 ~]$ rman target /

RMAN> restore controlfile from '/home/oracle/rman/1mv1thi1_1_1';

RMAN> sql ' alter database mount';

RMAN> restore database;

RMAN> recover database

Starting recover at 04-JUN-20

using target database control file instead of recovery catalog

allocated channel: ORA_DISK_1

channel ORA_DISK_1: SID=125 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: /u01/app/oracle/oradata/prod/system01.dbf

destination for restore of datafile 00002: /u01/app/oracle/oradata/prod/sysaux01.dbf

destination for restore of datafile 00003: /u01/app/oracle/oradata/prod/undotbs01.dbf

destination for restore of datafile 00004: /u01/app/oracle/oradata/prod/users01.dbf

destination for restore of datafile 00005: /u01/app/oracle/oradata/prod/example01.dbf

channel ORA_DISK_1: reading from backup piece /home/oracle/rman/1lv1thgk_1_1

channel ORA_DISK_1: piece handle=/home/oracle/rman/1lv1thgk_1_1 tag=TAG20200604T130939

channel ORA_DISK_1: restored backup piece 1

channel ORA_DISK_1: restore complete, elapsed time: 00:00:07

starting media recovery

unable to find archived log

archived log thread=1 sequence=6

RMAN-00571: ===========================================================

RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============

RMAN-00571: ===========================================================

RMAN-03002: failure of recover command at 06/04/2020 13:17:35

RMAN-06054: media recovery requesting unknown archived log for thread 1 with sequence 6 and starting SCN of 1199201

这个错误是什么原因呢：

（redo 日志不可用，控制文件找不到 redo 日志作为结尾，所以会一直读归档，直至找不到，无关紧要的报错，可以查看 SCN 来确定是否一致）

在RMAN恢复过程中，如果redo日志是可用的，那么RMAN可以找到他们并应用这些日志。如果redo日志不可用，此时就需要until子句指定修复的目标时间，SCN或日志序列号，他们是在联机重做日志的第一个SCN之前，否则RMAN会出现RMAN-6054错误。

如果最后创建的归档日志具有序列号n，那么指定until sequence n+1进行恢复就不会出现错误。

解决办法：

Run{

Restore database

Set until sequence 6

Recover database

}

SYS@prod>select checkpoint_change# from v$datafile;

CHECKPOINT_CHANGE#

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

   1199201

   1199201

   1199201

   1199201

   1199201

SYS@prod>select checkpoint_change# from v$datafile_header;

CHECKPOINT_CHANGE#

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

   1199201

   1199201

   1199201

   1199201

   1199201

SYS@prod>alter database open resetlogs;

Database altered.

SYS@prod>select count(*) from test;

  COUNT(*)

----------

   1391344

数据无丢失。