[20160406] 恢复until scn NNN.txt

[20160406] 恢复until scn NNN.txt

--昨天别人问的问题,如果使用rman恢复,restore database until scn NNN;是恢复到NNN,还是NNN-1.
--我个人的理解应该是NNN-1.包括像UNTIL SEQUENCE integer 以及UNTIL TIME xxx;也是少1个或者少1秒.
--实际上我以前如果做测试,我自己总是查询误操作的scn,然后仅仅恢复到减去1的scn号.(感觉这样比较保险^_^)

until
prep.到...为止, 在...以前
conj.到...为止, 在...以前, 直到...才

--即使查词霸也没有提示until是否包括这点.如果是"到...为止"我感觉应该包括这点.如果是"在...以前",感觉应该是不包括这点.
--还是通过测试说明问题.

1.环境:
SCOTT@book> @ &r/ver1

PORT_STRING                    VERSION        BANNER
------------------------------ -------------- --------------------------------------------------------------------------------
x86_64/Linux 2.4.xx            11.2.0.4.0     Oracle Database 11g Enterprise Edition Release 11.2.0.4.0 - 64bit Production

RMAN> report schema;
using target database control file instead of recovery catalog
Report of database schema for database with db_unique_name BOOK

List of Permanent Datafiles
===========================
File Size(MB) Tablespace           RB segs Datafile Name
---- -------- -------------------- ------- ------------------------
1    770      SYSTEM               ***     /mnt/ramdisk/book/system01.dbf
2    1580     SYSAUX               ***     /mnt/ramdisk/book/sysaux01.dbf
3    1435     UNDOTBS1             ***     /mnt/ramdisk/book/undotbs01.dbf
4    500      USERS                ***     /mnt/ramdisk/book/users01.dbf
5    346      EXAMPLE              ***     /mnt/ramdisk/book/example01.dbf
6    100      SUGAR                ***     /mnt/ramdisk/book/sugar01.dbf
7    1        TEA                  ***     /mnt/ramdisk/book/tea01.dbf

List of Temporary Files
=======================
File Size(MB) Tablespace           Maxsize(MB) Tempfile Name
---- -------- -------------------- ----------- --------------------
1    400      TEMP                 32767       /mnt/ramdisk/book/temp01.dbf

RMAN> backup database  format '/home/oracle/backup/full0406_%u' ;
RMAN> backup archivelog all format '/home/oracle/backup/archive0406_%u' ;

SCOTT@book> select * from scott.empx where rownum<=1;
     EMPNO ENAME      JOB              MGR HIREDATE                   SAL       COMM     DEPTNO
---------- ---------- --------- ---------- ------------------- ---------- ---------- ----------
      7369 ZZZZ       CLERK           7902 1980-12-17 00:00:00        800                    20

SCOTT@book> select * from dba_extents where owner=user and segment_name='EMPX';
OWNER  SEGMENT_NAME         SEGMENT_TYPE       TABLESPACE_NAME  EXTENT_ID    FILE_ID   BLOCK_ID      BYTES     BLOCKS RELATIVE_FNO
------ -------------------- ------------------ --------------- ---------- ---------- ---------- ---------- ---------- ------------
SCOTT  EMPX                 TABLE              TEA                      0          7        128      65536          8            7

--表EMPX在表空间TEA.

SCOTT@book> @ &r/logfile
GROUP# THREAD# SEQUENCE#       BYTES BLOCKSIZE MEMBERS ARC STATUS     FIRST_CHANGE# FIRST_TIME          NEXT_CHANGE# NEXT_TIME           GROUP# STATUS     TYPE       MEMBER                       IS_
------ ------- --------- ----------- --------- ------- --- ---------- ------------- ------------------- ------------ ------------------- ------ ---------- ---------- ---------------------------- ---
     1       1        28    52428800       512       1 YES INACTIVE     13227540144 2016-04-05 22:00:10  13227562225 2016-04-06 08:05:56      1            ONLINE     /mnt/ramdisk/book/redo01.log NO
     2       1        29    52428800       512       1 YES INACTIVE     13227562225 2016-04-06 08:05:56  13227565684 2016-04-06 09:23:33      2            ONLINE     /mnt/ramdisk/book/redo02.log NO
     3       1        30    52428800       512       1 NO  CURRENT      13227565684 2016-04-06 09:23:33 2.814750E+14                          3            ONLINE     /mnt/ramdisk/book/redo03.log NO

-当前日志是seq=30.

SCOTT@book> drop table empx purge ;
Table dropped.

SCOTT@book> alter system archive log current ;
System altered.

2.通过logminer确定drop的时间:

SELECT SCN
        ,timestamp "Time Stamp"
        ,seg_type_name "Segment Type Name"
        ,seg_owner "Segment Owner"
        ,seg_name "Segment Name"
        ,table_space "Tablespace"
        ,abs_file# "Abs File #"
        ,row_id "Row ID"
        ,session# "Session #"
        ,serial# "Serial #"
        ,session_info "Session Info"
        ,username "Username"
        ,operation "Operation"
        ,sql_redo "SQL Redo"
        ,sql_undo "SQL Undo"
        ,Info "Info"
        ,status "Status"
    FROM V$LOGMNR_CONTENTS
   WHERE seg_name = 'EMPX'
ORDER BY 1;

SCN:                13227565841
Time Stamp:         2016/04/06 09:26:36
Segment Type Name:  TABLE
Segment Owner:      SCOTT
Segment Name:       EMPX
Tablespace:        
Abs File #:         0
Row ID:             AAAAAAAAAAAAAAAAAB
Session #:          0
Serial #:           0
Session Info:       UNKNOWN
Username:           UNKNOWN
Operation:          DDL
SQL Redo:           drop table empx purge ;
SQL Undo:          
Info:               USER DDL (PlSql=0 RecDep=0)
Status:             0

--记下drop时候的scn号以及时间.

3.测试.

SYS@book> shutdown immediate ;
Database closed.
Database dismounted.
ORACLE instance shut down.

$ mv book book_0406
$ cd /mnt/ramdisk/
$ mkdir book

$ ll -l /home/oracle/backup
total 2181696
-rw-r----- 1 oracle oinstall    2564096 2016-04-06 09:23:33 archive0406_4ur2bfol
-rw-r----- 1 oracle oinstall 2219237376 2016-04-06 09:23:00 full0406_4sr2bfng
-rw-r----- 1 oracle oinstall   10059776 2016-04-06 09:23:12 full0406_4tr2bfnv

RMAN> startup nomount
Oracle instance started
Total System Global Area     634732544 bytes
Fixed Size                     2255792 bytes
Variable Size                197133392 bytes
Database Buffers             427819008 bytes
Redo Buffers                   7524352 bytes

RMAN> restore controlfile from '/home/oracle/backup/full0406_4tr2bfnv' ;
Starting restore at 2016-04-06 09:40:33
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=254 device type=DISK

channel ORA_DISK_1: restoring control file
channel ORA_DISK_1: restore complete, elapsed time: 00:00:01
output file name=/mnt/ramdisk/book/control01.ctl
output file name=/mnt/ramdisk/book/control02.ctl
Finished restore at 2016-04-06 09:40:34

RMAN> alter database mount ;
database mounted
released channel: ORA_DISK_1

4.恢复使用until seq方式:
--我跳过不需要恢复的文件,这样能节省磁盘空间以及恢复时间.仅仅需要恢复3个表空间system,tea,untotbs1.

run {
  allocate channel c1 device type DISK;
  allocate channel c2 device type DISK;
  set until sequence 30;
  restore database skip forever tablespace SYSAUX,USERS,EXAMPLE,SUGAR;
  recover database skip forever tablespace SYSAUX,USERS,EXAMPLE,SUGAR;
  release channel c1;
  release channel c2;
}

--摘录恢复过程其中一段:

archived log for thread 1 with sequence 29 is already on disk as file /u01/app/oracle/archivelog/book/1_29_907434361.dbf
archived log file name=/u01/app/oracle/archivelog/book/1_29_907434361.dbf thread=1 sequence=29
media recovery complete, elapsed time: 00:00:00
Finished recover at 2016-04-06 09:46:30

--可以发现恢复不包括sequence 30.

SYS@book> alter database open read only ;
Database altered.

SYS@book> select * from scott.empx where rownum<=1;

     EMPNO ENAME      JOB              MGR HIREDATE                   SAL       COMM     DEPTNO
---------- ---------- --------- ---------- ------------------- ---------- ---------- ----------
      7369 ZZZZ       CLERK           7902 1980-12-17 00:00:00        800                    20
--如果恢复到sequence 30,应该看不到上面信息.

5.恢复使用until scn方式:
SYS@book> shutdown immediate ;
Database closed.
Database dismounted.
ORACLE instance shut down.
SYS@book> startup mount
ORACLE instance started.
Total System Global Area  634732544 bytes
Fixed Size                  2255792 bytes
Variable Size             197133392 bytes
Database Buffers          427819008 bytes
Redo Buffers                7524352 bytes
Database mounted.

run {
  allocate channel c1 device type DISK;
  allocate channel c2 device type DISK;
  set until scn 13227565841;
  restore database skip forever tablespace SYSAUX,USERS,EXAMPLE,SUGAR;
  recover database skip forever tablespace SYSAUX,USERS,EXAMPLE,SUGAR;
  release channel c1;
  release channel c2;
}

SYS@book>  SELECT file#, CHECKPOINT_CHANGE#, CHECKPOINT_TIME,CREATION_CHANGE#  , RESETLOGS_CHANGE#,status, CHECKPOINT_COUNT,fuzzy,name,tablespace_name  FROM v$datafile_header where file# in (1,3,7);
FILE# CHECKPOINT_CHANGE# CHECKPOINT_TIME     CREATION_CHANGE# RESETLOGS_CHANGE# STATUS  CHECKPOINT_COUNT FUZ NAME                            TABLESPACE_NAME
----- ------------------ ------------------- ---------------- ----------------- ------- ---------------- --- ------------------------------- ----------------
    1        13227565841 2016-04-06 09:26:36                7       13227286650 ONLINE              1020 NO  /mnt/ramdisk/book/system01.dbf  SYSTEM
    3        13227565841 2016-04-06 09:26:36           923328       13227286650 ONLINE               935 NO  /mnt/ramdisk/book/undotbs01.dbf UNDOTBS1
    7        13227565841 2016-04-06 09:26:36      13227207527       13227286650 ONLINE                43 NO  /mnt/ramdisk/book/tea01.dbf     TEA

--这个视乎给人的感觉视乎是到了 CHECKPOINT_CHANGE#=13227565841.时间也恢复到了2016-04-06 09:26:36.(注:我个人不喜欢until time).

SYS@book> alter database open read only ;
Database altered.

SYS@book> select * from scott.empx where rownum<=1;
       EMPNO ENAME      JOB                MGR HIREDATE                     SAL         COMM       DEPTNO
------------ ---------- --------- ------------ ------------------- ------------ ------------ ------------
        7369 ZZZZ       CLERK             7902 1980-12-17 00:00:00          800                        20

--scn再加1看看:
SYS@book> shutdown immediate ;
Database closed.
Database dismounted.
ORACLE instance shut down.
SYS@book> startup mount
ORACLE instance started.
Total System Global Area    634732544 bytes
Fixed Size                    2255792 bytes
Variable Size               197133392 bytes
Database Buffers            427819008 bytes
Redo Buffers                  7524352 bytes
Database mounted.

run {
  allocate channel c1 device type DISK;
  allocate channel c2 device type DISK;
  set until scn 13227565842;
#  restore database skip forever tablespace SYSAUX,USERS,EXAMPLE,SUGAR;
  recover database skip forever tablespace SYSAUX,USERS,EXAMPLE,SUGAR;
  release channel c1;
  release channel c2;
}

SYS@book> SELECT file#, CHECKPOINT_CHANGE#, CHECKPOINT_TIME,CREATION_CHANGE#  , RESETLOGS_CHANGE#,status, CHECKPOINT_COUNT,fuzzy,name,tablespace_name  FROM v$datafile_header where file# in (1,3,7);
FILE# CHECKPOINT_CHANGE# CHECKPOINT_TIME     CREATION_CHANGE# RESETLOGS_CHANGE# STATUS  CHECKPOINT_COUNT FUZ NAME                            TABLESPACE_NAME
----- ------------------ ------------------- ---------------- ----------------- ------- ---------------- --- ------------------------------- ----------------
    1        13227565842 2016-04-06 09:26:36                7       13227286650 ONLINE              1020 NO  /mnt/ramdisk/book/system01.dbf  SYSTEM
    3        13227565842 2016-04-06 09:26:36           923328       13227286650 ONLINE               935 NO  /mnt/ramdisk/book/undotbs01.dbf UNDOTBS1
    7        13227565842 2016-04-06 09:26:36      13227207527       13227286650 ONLINE                43 NO  /mnt/ramdisk/book/tea01.dbf     TEA

SYS@book> alter database open read only ;
Database altered.

SYS@book> select * from scott.empx where rownum<=1;
       EMPNO ENAME      JOB                MGR HIREDATE                     SAL         COMM       DEPTNO
------------ ---------- --------- ------------ ------------------- ------------ ------------ ------------
        7369 ZZZZ       CLERK             7902 1980-12-17 00:00:00          800                        20

--奇怪吗?数据还在?

--scn再加1看看,测试结果数据还在.

--采用until time看看.注意这样写要定义环境变量
$ env | grep NLS
NLS_LANG=AMERICAN_AMERICA.zhs16gbk
NLS_TIMESTAMP_TZ_FORMAT=YYYY-MM-DD HH24:MI:SS.FF TZH:TZM
NLS_TIMESTAMP_FORMAT=YYYY-MM-DD HH24:MI:SS.FF
NLS_DATE_FORMAT=YYYY-MM-DD HH24:MI:SS

run {
  allocate channel c1 device type DISK;
  allocate channel c2 device type DISK;
  set until time '2016-04-06 09:26:37';
#  restore database skip forever tablespace SYSAUX,USERS,EXAMPLE,SUGAR;
  recover database skip forever tablespace SYSAUX,USERS,EXAMPLE,SUGAR;
  release channel c1;
  release channel c2;
}

SYS@book> SELECT file#, CHECKPOINT_CHANGE#, CHECKPOINT_TIME,CREATION_CHANGE#  , RESETLOGS_CHANGE#,status, CHECKPOINT_COUNT,fuzzy,name,tablespace_name  FROM v$datafile_header where file# in (1,3,7);
FILE# CHECKPOINT_CHANGE# CHECKPOINT_TIME     CREATION_CHANGE# RESETLOGS_CHANGE# STATUS  CHECKPOINT_COUNT FUZ NAME                            TABLESPACE_NAME
----- ------------------ ------------------- ---------------- ----------------- ------- ---------------- --- ------------------------------- ---------------
    1        13227565859 2016-04-06 09:26:39                7       13227286650 ONLINE              1020 NO  /mnt/ramdisk/book/system01.dbf  SYSTEM
    3        13227565859 2016-04-06 09:26:39           923328       13227286650 ONLINE               935 NO  /mnt/ramdisk/book/undotbs01.dbf UNDOTBS1
    7        13227565859 2016-04-06 09:26:39      13227207527       13227286650 ONLINE                43 NO  /mnt/ramdisk/book/tea01.dbf     TEA

--注意看时间实际上恢复到"2016-04-06 09:26:39".与实际的不同,我个人建议不要使用时间方式.scn=13227565859.

SYS@book> alter database open read only ;
Database altered.

SYS@book> select * from scott.empx where rownum<=1;
select * from scott.empx where rownum<=1
                    *
ERROR at line 1:
ORA-00942: table or view does not exist

--我最终测试恢复到scn 13227565849还可以看到数据.scn 13227565850就不行了.

run {
  allocate channel c1 device type DISK;
  allocate channel c2 device type DISK;
  set until scn 13227565849;
  restore database skip forever tablespace SYSAUX,USERS,EXAMPLE,SUGAR;
  recover database skip forever tablespace SYSAUX,USERS,EXAMPLE,SUGAR;
  release channel c1;
  release channel c2;
}

SYS@book> SELECT file#, CHECKPOINT_CHANGE#, CHECKPOINT_TIME,CREATION_CHANGE#  , RESETLOGS_CHANGE#,status, CHECKPOINT_COUNT,fuzzy,name,tablespace_name  FROM v$datafile_header where file# in (1,3,7);
FILE# CHECKPOINT_CHANGE# CHECKPOINT_TIME     CREATION_CHANGE# RESETLOGS_CHANGE# STATUS  CHECKPOINT_COUNT FUZ NAME                             TABLESPACE_NAME
----- ------------------ ------------------- ---------------- ----------------- ------- ---------------- --- -------------------------------- ----------------
    1        13227565849 2016-04-06 09:26:36                7       13227286650 ONLINE              1020 NO  /mnt/ramdisk/book/system01.dbf   SYSTEM
    3        13227565849 2016-04-06 09:26:36           923328       13227286650 ONLINE               935 NO  /mnt/ramdisk/book/undotbs01.dbf  UNDOTBS1
    7        13227565849 2016-04-06 09:26:36      13227207527       13227286650 ONLINE                43 NO  /mnt/ramdisk/book/tea01.dbf      TEA

SYS@book> alter database open read only ;
Database altered.

SYS@book> select * from scott.empx where rownum<=1;
       EMPNO ENAME      JOB                MGR HIREDATE                     SAL         COMM       DEPTNO
------------ ---------- --------- ------------ ------------------- ------------ ------------ ------------
        7369 ZZZZ       CLERK             7902 1980-12-17 00:00:00          800                        20

run {
  allocate channel c1 device type DISK;
  allocate channel c2 device type DISK;
  set until scn 13227565850;
  restore database skip forever tablespace SYSAUX,USERS,EXAMPLE,SUGAR;
  recover database skip forever tablespace SYSAUX,USERS,EXAMPLE,SUGAR;
  release channel c1;
  release channel c2;
}

SYS@book> SELECT file#, CHECKPOINT_CHANGE#, CHECKPOINT_TIME,CREATION_CHANGE#  , RESETLOGS_CHANGE#,status, CHECKPOINT_COUNT,fuzzy,name,tablespace_name  FROM v$datafile_header where file# in (1,3,7);
FILE# CHECKPOINT_CHANGE# CHECKPOINT_TIME     CREATION_CHANGE# RESETLOGS_CHANGE# STATUS  CHECKPOINT_COUNT FUZ NAME                             TABLESPACE_NAME
----- ------------------ ------------------- ---------------- ----------------- ------- ---------------- --- -------------------------------- ---------------
    1        13227565850 2016-04-06 09:26:36                7       13227286650 ONLINE              1020 NO  /mnt/ramdisk/book/system01.dbf   SYSTEM
    3        13227565850 2016-04-06 09:26:36           923328       13227286650 ONLINE               935 NO  /mnt/ramdisk/book/undotbs01.dbf  UNDOTBS1
    7        13227565850 2016-04-06 09:26:36      13227207527       13227286650 ONLINE                43 NO  /mnt/ramdisk/book/tea01.dbf      TEA

SYS@book> alter database open read only ;
Database altered.

SYS@book> select * from scott.empx where rownum<=1;
select * from scott.empx where rownum<=1
                    *
ERROR at line 1:
ORA-00942: table or view does not exist

--感觉越做越糊涂.总之选择scn比较准确.觉得应该还是以查询到的v$datafile_header为准.
--补充做until time的情况:

run {
  allocate channel c1 device type DISK;
  allocate channel c2 device type DISK;
  set until time '2016-04-06 09:26:36';
  restore database skip forever tablespace SYSAUX,USERS,EXAMPLE,SUGAR;
  recover database skip forever tablespace SYSAUX,USERS,EXAMPLE,SUGAR;
  release channel c1;
  release channel c2;
}

SYS@book> SELECT file#, CHECKPOINT_CHANGE#, CHECKPOINT_TIME,CREATION_CHANGE#  , RESETLOGS_CHANGE#,status, CHECKPOINT_COUNT,fuzzy,name,tablespace_name  FROM v$datafile_header where file# in (1,3,7);
FILE# CHECKPOINT_CHANGE# CHECKPOINT_TIME     CREATION_CHANGE# RESETLOGS_CHANGE# STATUS  CHECKPOINT_COUNT FUZ NAME                             TABLESPACE_NAME
----- ------------------ ------------------- ---------------- ----------------- ------- ---------------- --- -------------------------------- ---------------
    1        13227565836 2016-04-06 09:26:36                7       13227286650 ONLINE              1020 NO  /mnt/ramdisk/book/system01.dbf   SYSTEM
    3        13227565836 2016-04-06 09:26:36           923328       13227286650 ONLINE               935 NO  /mnt/ramdisk/book/undotbs01.dbf  UNDOTBS1
    7        13227565836 2016-04-06 09:26:36      13227207527       13227286650 ONLINE                43 NO  /mnt/ramdisk/book/tea01.dbf      TEA

--可以发现以时间恢复,scn=13227565836,更加靠前.这个可以更加确定应该不包括这个时间点.

--总结:
--做不完全恢复,选择scn为准.这样比较准确.选择时间可能存在一定的偏差.
--until sequence NNN,仅仅恢复到NNN-1.
--until scn NNN,我自己的理解应该还是在NNN-1之前.不过还是以查看视图v$datafile_header为准吧.
--until time 'XXX',存在一定的不可控因素,最好不要选择.

时间： 2024-10-23 08:45:36

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