rman 恢复时候提示 ORA-01547、ORA-01194、ORA-01110

在异机恢复数据库的时候，restore正常，recover的时候，很快就过去了。提示ORA-01547、ORA-01194、ORA-01110错误。从错误提示中看，归档日志不存在。

starting media recovery
 
Oracle Error: 
ORA-01547: warning: RECOVER succeeded but OPEN RESETLOGS would get error below
ORA-01194: file 1 needs more recovery to be consistent
ORA-01110: data file 1: '+DATA/abcd/datafile/system.502.1108624865'
 
released channel: c1
released channel: c2
released channel: c3
released channel: c4
RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of recover command at 06/29/2022 18:22:55
RMAN-06053: unable to perform media recovery because of missing log
RMAN-06025: no backup of archived log for thread 2 with sequence 125966 and starting SCN of 6234223614488 found to restore
RMAN-06025: no backup of archived log for thread 2 with sequence 125965 and starting SCN of 6234223488894 found to restore
RMAN-06025: no backup of archived log for thread 2 with sequence 125964 and starting SCN of 6234218899569 found to restore
RMAN-06025: no backup of archived log for thread 2 with sequence 125963 and starting SCN of 6234214130922 found to restore
RMAN-06025: no backup of archived log for thread 1 with sequence 137219 and starting SCN of 6234221221375 found to restore
RMAN-06025: no backup of archived log for thread 1 with sequence 137218 and starting SCN of 6234214130457 found to restore
 
Recovery Manager complete.

疑惑：

1 缺失的这些归档，都是最后的几个归档，按照道理，应该是先使用序号较小的归档做recover，最后才会发现没有这些缺失的归档，怎么一晃就结束了 。难道oracle检测到缺失归档，就不给恢复，没道理啊？

2 为什么会一晃而过？明明是有对归档做备份的，有备份集的。

3 是否为bug？mos上有案例，只说了解决方法，没有说是不是bug。

解决方法：参考MOS文档，做了不完全恢复。也就是找到那个scn开始，数据是一致的。最后做了不完全恢复。

参考文档：Open Database failed - DATAFILE NEEDS MORE RECOVERY TO BE CONSISTENT ORA-1194 ORA-1547 ORA-1110 (Doc ID 1528788.1)

在官网中，参考以下内容，做不一致恢复 （ABSSCN = Absolute SCN ）

The following query will show you the SCN to which we must at least recover to, to get all datafiles consistent.

SQL> select  min(FHSCN) "LOW FILEHDR SCN"
           , max(FHSCN) "MAX FILEHDR SCN"
           , max(FHAFS) "Min PITR ABSSCN"
       from X$KCVFH ;

LOW FILEHDR SCN  MAX FILEHDR SCN  Min PITR ABSSCN
---------------- ---------------- ----------------
2446300          2472049          0


-- Example output explained:
--
-- "LOW FILEHDR SCN"  - this is the SCN at which recovery process starts
-- "MAX FILEHDR SCN"  - this is the SCN we must recover to to get all datafiles consistent
--
--   IF    "Min PITR ABSSCN"  != 0 AND  >  "MAX FILEHDR SCN"
--   THEN  "Min PITR ABSSCN"  is the SCN we must recover to to get all datafiles consistent
 

自己的环境中查询到的结果 

SYS@abcd>select  min(FHSCN) "LOW FILEHDR SCN"
  2             , max(FHSCN) "MAX FILEHDR SCN"
  3             , max(FHAFS) "Min PITR ABSSCN"
  4          from X$KCVFH ;
 
LOW FILEHDR SCN                  MAX FILEHDR SCN                  Min PITR ABSSCN
-------------------------------- -------------------------------- --------------------------------
6234167427056                    6234207627035                    6234213805895
 
SYS@abcd>

可以看到和官方的说法比较吻合。使用不完全恢复。
recover database until scn 6234213805895;	 -- 使用的是这个 

最后，open resetlogs 开库。