[20161220]rman恢复时间点的疑问.txt
--昨天在恢复时遇到缺少归档的问题,自己开始感觉奇怪,做一点分析记录.
RMAN> list backupset summary ;
List of Backups
===============
Key TY LV S Device Type Completion Time #Pieces #Copies Compressed Tag
------- -- -- - ----------- ------------------- ------- ------- ---------- ---
...
3899 B F A DISK 2016-12-03 03:31:43 1 1 YES FULL 2016/12/03 03:31:01
3900 B F A DISK 2016-12-03 03:31:51 1 1 YES FULL 2016/12/03 03:31:01
3901 B F A DISK 2016-12-03 03:31:53 1 1 YES FULL 2016/12/03 03:31:01
3902 B F A DISK 2016-12-03 03:32:27 1 1 YES FULL 2016/12/03 03:31:01
3903 B F A DISK 2016-12-03 03:39:14 1 1 YES FULL 2016/12/03 03:31:01
3904 B A A DISK 2016-12-03 03:39:18 1 1 YES ARCHIVELOG 2016/12/03 03:31:01
3905 B A A DISK 2016-12-03 03:39:21 1 1 YES ARCHIVELOG 2016/12/03 03:31:01
3906 B A A DISK 2016-12-03 03:39:21 1 1 YES ARCHIVELOG 2016/12/03 03:31:01
--但是我执行如下恢复,提示缺少seq=15300的归档.
recover database until time '2016-12-03 03:39:20';
--我认为archivelog备份的完成时间是2016-12-03 03:39:21.应该可以.
--按照道理全备份完成后要切换一次日志,但是提示缺少一个seq=15300,为什么呢?
RMAN> list backupset 3903;
List of Backup Sets
===================
BS Key Type LV Size Device Type Elapsed Time Completion Time
------- ---- -- ---------- ----------- ------------ -------------------
3903 Full 2.02G DISK 00:08:10 2016-12-03 03:39:14
BP Key: 3903 Status: AVAILABLE Compressed: YES Tag: FULL 2016/12/03 03:31:01
Piece Name: /mnt/tongji230.backup/fulls/tongji230_STATISTI_20161203_3913_full
List of Datafiles in backup set 3903
File LV Type Ckp SCN Ckp Time Name
---- -- ---- ---------- ------------------- ----
4 Full 16940567563 2016-12-03 03:31:04 /u01/app/oracle/oradata/statisti/users01.dbf
5 Full 16940567563 2016-12-03 03:31:04 /u01/app/oracle/oradata/statisti/statistics.dbf
--//可以看出全备份数据文件的完成时间在'2016-12-03 03:39:14'.
RMAN> list backupset by file tag ='ARCHIVELOG 2016/12/03 03:31:01';
List of Archived Log Backups
============================
Thrd Seq Low SCN Low Time BS Key S #Pieces #Copies Compressed Tag
---- ------- ---------- ------------------- ------- - ------- ------- ---------- ---
1 15297 16933543374 2016-12-02 03:31:05 3906 A 1 1 YES ARCHIVELOG 2016/12/03 03:31:01
1 15298 16940500469 2016-12-02 22:00:32 3905 A 1 1 YES ARCHIVELOG 2016/12/03 03:31:01
1 15299 16940567740 2016-12-03 03:39:15 3904 A 1 1 YES ARCHIVELOG 2016/12/03 03:31:01
--//seq=15299,Low Time='2016-12-03 03:39:15',可以想像这个是全备份完成后切换的归档日志.这个显示有1点点奇怪的是,仅仅显示Low SCN,Low Time.
--//并没有显示Next SCN,Next Time.换1个方式执行:
RMAN> list backupset 3904;
List of Backup Sets
===================
BS Key Size Device Type Elapsed Time Completion Time
------- ---------- ----------- ------------ -------------------
3904 2.00K DISK 00:00:02 2016-12-03 03:39:18
BP Key: 3904 Status: AVAILABLE Compressed: YES Tag: ARCHIVELOG 2016/12/03 03:31:01
Piece Name: /mnt/tongji230.backup/archives/tongji230_STATISTI_20161203_3920_archive
List of Archived Logs in backup set 3904
Thrd Seq Low SCN Low Time Next SCN Next Time
---- ------- ---------- ------------------- ------------ ---------
1 15299 16940567740 2016-12-03 03:39:15 16940567745 2016-12-03 03:39:16
--从结果看备份seq=15299,Next Time=2016-12-03 03:39:16.所以讲恢复只能到'2016-12-03 03:39:16'时间.
--如果恢复'2016-12-03 03:39:20',自然需要seq=15300.
RMAN> recover database test until time '2016-12-03 03:39:16' ;
--我自己认为理解错误!!
--实际上seq=15297,15298的备份文件都很大,而seq=15299是最后切换出来的,归档文件很小,我开了3个通道,这样3个归档分别在不同的通道上备份,
--seq=15299的最先完成备份,而剩下的2个归档文件比较大,所以完成时间推后一点.
--另外我没有仔细看前面的key对应的归档备份.
BS Key=3904,对应的seq=15299.
BS Key=3905,对应的seq=15298.
BS Key=3906,对应的seq=15297.
--//正好反过来.理解错误啊.
RMAN> list backupset tag ='ARCHIVELOG 2016/12/03 03:31:01' ;
List of Backup Sets
===================
BS Key Size Device Type Elapsed Time Completion Time
------- ---------- ----------- ------------ -------------------
3904 2.00K DISK 00:00:02 2016-12-03 03:39:18
BP Key: 3904 Status: AVAILABLE Compressed: YES Tag: ARCHIVELOG 2016/12/03 03:31:01
Piece Name: /mnt/tongji230.backup/archives/tongji230_STATISTI_20161203_3920_archive
List of Archived Logs in backup set 3904
Thrd Seq Low SCN Low Time Next SCN Next Time
---- ------- ---------- ------------------- ---------- ---------
1 15299 16940567740 2016-12-03 03:39:15 16940567745 2016-12-03 03:39:16
BS Key Size Device Type Elapsed Time Completion Time
------- ---------- ----------- ------------ -------------------
3905 13.43M DISK 00:00:05 2016-12-03 03:39:21
BP Key: 3905 Status: AVAILABLE Compressed: YES Tag: ARCHIVELOG 2016/12/03 03:31:01
Piece Name: /mnt/tongji230.backup/archives/tongji230_STATISTI_20161203_3919_archive
List of Archived Logs in backup set 3905
Thrd Seq Low SCN Low Time Next SCN Next Time
---- ------- ---------- ------------------- ---------- ---------
1 15298 16940500469 2016-12-02 22:00:32 16940567740 2016-12-03 03:39:15
BS Key Size Device Type Elapsed Time Completion Time
------- ---------- ----------- ------------ -------------------
3906 15.79M DISK 00:00:05 2016-12-03 03:39:21
BP Key: 3906 Status: AVAILABLE Compressed: YES Tag: ARCHIVELOG 2016/12/03 03:31:01
Piece Name: /mnt/tongji230.backup/archives/tongji230_STATISTI_20161203_3918_archive
List of Archived Logs in backup set 3906
Thrd Seq Low SCN Low Time Next SCN Next Time
---- ------- ---------- ------------------- ---------- ---------
1 15297 16933543374 2016-12-02 03:31:05 16940500469 2016-12-02 22:00:32