Cancel based recovery

Question

dear dba's,
i'm using oracle 11gR2 in windows 2003 sever S2.
could anyone tell me
1. what is CANCEL BASED RECOVERY
2. pls give the commands with an explanation
3. In which suituation we must use this type of recovery.
Thanks & Regards,
John Marshal.A

Answer 1

+1. what is CANCEL BASED RECOVERY+
It is an incomplete recovery option , at particular time you want to recover yours database for an audit purpose or to avoid any logical error by users in past , but flashback technology now been dominant to cancel based reocovery.
+2. pls give the commands with an explanation+
+3. In which suituation we must use this type of recovery.+
When yours controlfile does not know when so far yours recover could be go on and on by "recover database using backup controlfile until cancel" yours restored controlfile from backup typically does not know how far i need redo if you are doing manual recovery while RMAN does not need cancel based recovery it will keep applying log until it finds and bumped out with an error RMAN-06054: media recovery requesting unknown archived log for ..... .
Situation could be manual recovery in general when you do not define time.scn based recovery using until clause.
Copied from my blog but need to be a bit changes thats why pasting here.
Scenario 1
I lost all data file but my control file is intact at the same location where it was , before lost datafiles i have backed up the data files, controlfile and archive logs.
If you are just restoring the data files and not control files then you may know how much archive log sequence required for yours recovery after the backup taken using archived log repository.
RMAN> backup database;
Starting backup at 02-OCT-09
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=128 device type=DISK
channel ORA_DISK_1: starting full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
input datafile file number=00001 name=/u01/app/oracle/oradata/his/system01.dbf
input datafile file number=00002 name=/u01/app/oracle/oradata/his/sysaux01.dbf
input datafile file number=00003 name=/u01/app/oracle/oradata/his/undotbs01.dbf
input datafile file number=00004 name=/u01/app/oracle/oradata/his/users01.dbf
channel ORA_DISK_1: starting piece 1 at 02-OCT-09
channel ORA_DISK_1: finished piece 1 at 02-OCT-09
piece handle=/u01/app/oracle/flash_recovery_area/HIS/backupset/2009_10_02/o1_mf_nnndf_TAG20091002T112226_5dc712wg_.bkp tag=TAG20091002T112226 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:45
Finished backup at 02-OCT-09
Starting Control File and SPFILE Autobackup at 02-OCT-09
piece handle=/u01/app/oracle/flash_recovery_area/HIS/autobackup/2009_10_02/o1_mf_s_699189791_5dc72j13_.bkp comment=NONE
Finished Control File and SPFILE Autobackup at 02-OCT-09
RMAN> sql 'alter system archive log current';
using target database control file instead of recovery catalog
sql statement: alter system archive log current
RMAN> sql 'alter system archive log current';
sql statement: alter system archive log current
RMAN> sql 'alter system archive log current';
sql statement: alter system archive log current
RMAN> exit
Recovery Manager complete.
[oracle@khurram his]$ sqlplus / as sysdba
SQL*Plus: Release 11.1.0.6.0 - Production on Fri Oct 2 11:24:04 2009
Copyright (c) 1982, 2007, Oracle.  All rights reserved.
Connected to:
Oracle Database 11g Enterprise Edition Release 11.1.0.6.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
SQL> select name,sequence#
  2    from v$archived_log
  3   where status='A'
  4  /
NAME                                                                                 SEQUENCE#
/u01/app/oracle/product/11.1.0/db_1/dbs/arch1_2_699187272.dbf                           2
/u01/app/oracle/flash_recovery_area/HIS/archivelog/2009_10_02/o1_mf_1_2_5dc73qw2_.arc   2
/u01/app/oracle/product/11.1.0/db_1/dbs/arch1_3_699187272.dbf                           3
/u01/app/oracle/flash_recovery_area/HIS/archivelog/2009_10_02/o1_mf_1_3_5dc73vgm_.arc   3
/u01/app/oracle/product/11.1.0/db_1/dbs/arch1_4_699187272.dbf                           4
/u01/app/oracle/flash_recovery_area/HIS/archivelog/2009_10_02/o1_mf_1_4_5dc740d7_.arc   4
6 rows selected.You may know if yours control file intact (not lost or restored from backup), you may know how much recovery will go so far by knowing archived logs repository (conrolfile).From above v$archived_log archveilog repository you are seeing that after backup there are sequence required for the archive logs are 2,3 and 4 for recovering the restored backup which you have taken as above.
SQL> exit
Disconnected from Oracle Database 11g Enterprise Edition Release 11.1.0.6.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
[oracle@khurram his]$ cd /u01/app/oracle/oradata/his/*.dbf
bash: cd: /u01/app/oracle/oradata/his/sysaux01.dbf: Not a directory
[oracle@khurram his]$ rm -rf  /u01/app/oracle/oradata/his/*.dbf
[oracle@khurram his]$ sqlplus / as sysdba
SQL*Plus: Release 11.1.0.6.0 - Production on Fri Oct 2 11:28:01 2009
Copyright (c) 1982, 2007, Oracle.  All rights reserved.
Connected to:
Oracle Database 11g Enterprise Edition Release 11.1.0.6.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
SQL> shutdown abort
ORACLE instance shut down.
SQL> startup mount
ORACLE instance started.
Total System Global Area 1620115456 bytes
Fixed Size                  2144864 bytes
Variable Size             922748320 bytes
Database Buffers          687865856 bytes
Redo Buffers                7356416 bytes
Database mounted.
SQL> exit
Disconnected from Oracle Database 11g Enterprise Edition Release 11.1.0.6.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
[oracle@khurram his]$ rman target /
Recovery Manager: Release 11.1.0.6.0 - Production on Fri Oct 2 11:29:30 2009
Copyright (c) 1982, 2007, Oracle.  All rights reserved.
connected to target database: HIS (DBID=3219691467, not open)
RMAN> restore database;
Starting restore at 02-OCT-09
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=154 device type=DISK
channel ORA_DISK_1: starting datafile backup set restore
channel ORA_DISK_1: specifying datafile(s) to restore from backup set
channel ORA_DISK_1: restoring datafile 00001 to /u01/app/oracle/oradata/his/system01.dbf
channel ORA_DISK_1: restoring datafile 00002 to /u01/app/oracle/oradata/his/sysaux01.dbf
channel ORA_DISK_1: restoring datafile 00003 to /u01/app/oracle/oradata/his/undotbs01.dbf
channel ORA_DISK_1: restoring datafile 00004 to /u01/app/oracle/oradata/his/users01.dbf
channel ORA_DISK_1: reading from backup piece /u01/app/oracle/flash_recovery_area/HIS/backupset/2009_10_02/o1_mf_nnndf_TAG20091002T112226_5dc712wg_.bkp
channel ORA_DISK_1: piece handle=/u01/app/oracle/flash_recovery_area/HIS/backupset/2009_10_02/o1_mf_nnndf_TAG20091002T112226_5dc712wg_.bkp tag=TAG20091002T112226
channel ORA_DISK_1: restored backup piece 1
channel ORA_DISK_1: restore complete, elapsed time: 00:00:35
Finished restore at 02-OCT-09
RMAN> recover database;
Starting recover at 02-OCT-09
using channel ORA_DISK_1
starting media recovery
archived log for thread 1 with sequence 2 is already on disk as file /u01/app/oracle/flash_recovery_area/HIS/archivelog/2009_10_02/o1_mf_1_2_5dc73qw2_.arc
archived log for thread 1 with sequence 3 is already on disk as file /u01/app/oracle/flash_recovery_area/HIS/archivelog/2009_10_02/o1_mf_1_3_5dc73vgm_.arc
archived log for thread 1 with sequence 4 is already on disk as file /u01/app/oracle/flash_recovery_area/HIS/archivelog/2009_10_02/o1_mf_1_4_5dc740d7_.arc
archived log file name=/u01/app/oracle/flash_recovery_area/HIS/archivelog/2009_10_02/o1_mf_1_2_5dc73qw2_.arc thread=1 sequence=2
media recovery complete, elapsed time: 00:00:01
Finished recover at 02-OCT-09
as you can see that 2,3,4 were required during recovery process.Scenario 2
I lost all data file as well control file , i have backed up the data files, controlfile and archive logs.
Its like a disastre you lost alls data file and as well controlfile , if you backed the controlfile then remember during controlfile backup it will have file type flag 4 that tells Oracle it is a backup control file. The Stop SCN for alls data file marked to 0xffff.ffffffff (infinity).File type flag in the backup control file tells to oracle that it cannot rely on its redo thread,which means recovering will go on and on , controlfile will not aware how much should i go for redo it will never stop if you are able to supply redo.
It will always ask you more subsequent redo if you already supplied to it during process that's why it let you open the database in reset logs.
Lets see after restoring the controlfile and datafiles , you will see SQL tool recovery mechanism ask you recover database using backup controlfile which shows that controlfile does not know where to end the applying redo chain.
Here an excerpt which shows that restored controlfile does not know till how long the redo should be applied, its the RMAN robustness which does not ask you manually to supply redo, RMAN search the alls redo from archivelogs and if possible you have redo within redo logs.But if you are not with RMAN i.e recovering by SQL then you have to cancel recovery at some end.
RMAN> shutdown abort
Oracle instance shut down
RMAN> exit
Recovery Manager complete.
[oracle@khurram ~]$ rm -rf /u01/app/oracle/oradata/his/*
[oracle@khurram ~]$ rman target /
Recovery Manager: Release 11.1.0.6.0 - Production on Fri Oct 2 09:32:37 2009
Copyright (c) 1982, 2007, Oracle.  All rights reserved.
connected to target database (not started)
RMAN> startup nomount
Oracle instance started
Total System Global Area    1620115456 bytes
Fixed Size                     2144864 bytes
Variable Size                922748320 bytes
Database Buffers             687865856 bytes
Redo Buffers                   7356416 bytes
RMAN> restore controlfile from autobackup;
Starting restore at 02-OCT-09
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=153 device type=DISK
recovery area destination: /u01/app/oracle/flash_recovery_area
database name (or database unique name) used for search: HIS
channel ORA_DISK_1: AUTOBACKUP /u01/app/oracle/flash_recovery_area/HIS/autobackup/2009_10_02/o1_mf_s_699182899_5dc0c49t_.bkp found in the recovery area
AUTOBACKUP search with format "%F" not attempted because DBID was not set
channel ORA_DISK_1: restoring control file from AUTOBACKUP /u01/app/oracle/flash_recovery_area/HIS/autobackup/2009_10_02/o1_mf_s_699182899_5dc0c49t_.bkp
channel ORA_DISK_1: control file restore from AUTOBACKUP complete
output file name=/u01/app/oracle/oradata/his/control01.ctl
output file name=/u01/app/oracle/oradata/his/control02.ctl
output file name=/u01/app/oracle/oradata/his/control03.ctl
Finished restore at 02-OCT-09
RMAN> alter database mount;
database mounted
released channel: ORA_DISK_1
RMAN> restore database;
Starting restore at 02-OCT-09
Starting implicit crosscheck backup at 02-OCT-09
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=153 device type=DISK
Crosschecked 1 objects
Finished implicit crosscheck backup at 02-OCT-09
Starting implicit crosscheck copy at 02-OCT-09
using channel ORA_DISK_1
Finished implicit crosscheck copy at 02-OCT-09
searching for all files in the recovery area
cataloging files...
cataloging done
List of Cataloged Files
=======================
File Name: /u01/app/oracle/flash_recovery_area/HIS/autobackup/2009_10_02/o1_mf_s_699182899_5dc0c49t_.bkp
File Name: /u01/app/oracle/flash_recovery_area/HIS/archivelog/2009_10_02/o1_mf_1_5_5dc0d1m8_.arc
File Name: /u01/app/oracle/flash_recovery_area/HIS/archivelog/2009_10_02/o1_mf_1_3_5dc0cx6p_.arc
File Name: /u01/app/oracle/flash_recovery_area/HIS/archivelog/2009_10_02/o1_mf_1_4_5dc0czx3_.arc
using channel ORA_DISK_1
channel ORA_DISK_1: starting datafile backup set restore
channel ORA_DISK_1: specifying datafile(s) to restore from backup set
channel ORA_DISK_1: restoring datafile 00001 to /u01/app/oracle/oradata/his/system01.dbf
channel ORA_DISK_1: restoring datafile 00002 to /u01/app/oracle/oradata/his/sysaux01.dbf
channel ORA_DISK_1: restoring datafile 00003 to /u01/app/oracle/oradata/his/undotbs01.dbf
channel ORA_DISK_1: restoring datafile 00004 to /u01/app/oracle/oradata/his/users01.dbf
channel ORA_DISK_1: reading from backup piece /u01/app/oracle/flash_recovery_area/HIS/backupset/2009_10_02/o1_mf_nnndf_TAG20091002T092724_5dc09dlc_.bkp
channel ORA_DISK_1: piece handle=/u01/app/oracle/flash_recovery_area/HIS/backupset/2009_10_02/o1_mf_nnndf_TAG20091002T092724_5dc09dlc_.bkp tag=TAG20091002T092724
channel ORA_DISK_1: restored backup piece 1
channel ORA_DISK_1: restore complete, elapsed time: 00:00:45
Finished restore at 02-OCT-09
[oracle@khurram ~]$ sqlplus / as sysdba
SQL*Plus: Release 11.1.0.6.0 - Production on Fri Oct 2 09:34:51 2009
Copyright (c) 1982, 2007, Oracle.  All rights reserved.
Connected to:
Oracle Database 11g Enterprise Edition Release 11.1.0.6.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
SQL> recover database using backup contorlfile until cancel
Keep applying log as you can and you have and cancel at an end when alls logs are supplied to recovery process.