On ORA-02266: unique/primary keys in table referenced by enabled foreign keys

Few days ago I received an email from a user who had two empty table, one referenced by the other. He was not able to execute a truncate command on the parent table and asked me to solve his error: ORA-02266: unique/primary keys in table referenced by enabled foreign keys.

Truncate command is very useful when you want to completely remove all data from a table: for very large tables it is usually the best way to remove your data.
When you use the TRUNCATE command Oracle sets back to zero the HWM (high-water mark) of the table and, compared with the DELETE command, less UNDO and REDO information is generated.
You can query the dba_extents to see how many extents are allocated for your table.

However using TRUNCATE command has some "disadvantages": first you have to remember it's a DDL command so it will commit automatically any pending transactions. Another one is that you can receive the following error when the table you are truncating is referenced by an "enabled" foreign key: ORA-02266: unique/primary keys in table referenced by enabled foreign keys.
To successfully complete your TRUNCATE command you have to temporarily disable the foreign key.

Let's see it with an example.
Create two tables: one table (hr.parent) has one primary key referenced by a second table (hr.child) using a constraint.

SQL> create table hr.parent (a number);

Table created.

SQL> create table hr.child (b number, a_ref number);

Table created.

SQL> create index parent_pk on hr.parent(a);

Index created.

SQL> alter table hr.parent add constraint parent_pk primary key (a);

Table altered.

SQL> alter table hr.child add constraint child_fk foreign key (a_ref) references hr.parent (a);

Table altered.

No extent is allocated for PARENT table. I'm working with Oracle Database 11G R2, so have a look at deferred_segment_creation initialization parameter to justify why you have zero extent allocated (or read this link)

SQL> select count(*) from dba_extents
  2  where segment_name = 'PARENT';

  COUNT(*)
----------
         0

And no rows still are created.

SQL> select * from hr.parent;

no rows selected

SQL> select count(*) from hr.child;

  COUNT(*)
----------
         0

In this situation we can truncate our PARENT table with any problem.

SQL> truncate table hr.parent;

Table truncated.

But what does it happen when records are inserted into it ? Let's populate PARENT table with some data:

SQL> begin
  2  for  indx IN 1 .. 10000
  3  loop
  4      execute immediate 'insert into hr.parent values (:1)' using indx;
  5  end loop;
  6  commit;
  7  end;
  8  /

PL/SQL procedure successfully completed.

PARENT table is now formed by 3 extents.

SQL> select count(*) from dba_extents
  2  where segment_name = 'PARENT';

  COUNT(*)
----------
         3

As you can see we are no more allowed to truncate PARENT table even if any data on CHILD table are referencing to it.

SQL>  truncate table hr.parent;
 truncate table hr.parent
                   *
ERROR at line 1:
ORA-02266: unique/primary keys in table referenced by enabled foreign keys

SQL> select count(*) from hr.child;

  COUNT(*)
----------
         0

To successfully complete the truncate command we have to disable the foreign key...

SQL> alter table hr.child modify constraint child_fk disable;

Table altered.

... execute the truncate command...

SQL>  truncate table hr.parent;

Table truncated.

.. and enable again the foreign key.

SQL> alter table hr.child modify constraint child_fk enable;

Table altered.

PARENT table is now formed by one extent.

SQL> select count(*) from dba_extents
  2  where segment_name = 'PARENT';

  COUNT(*)
----------
         1

Let's populate again PARENT table with 10000 records:

SQL> begin
  2  for  indx IN 1 .. 10000
  3  loop
  4      execute immediate 'insert into hr.parent values (:1)' using indx;
  5  end loop;
  6  commit;
  7  end;
  8  /

PL/SQL procedure successfully completed.

PARENT table is formed by 3 extents.

SQL> select count(*) from dba_extents
  2  where segment_name = 'PARENT';

  COUNT(*)
----------
         3

Let's see what it happens to the HWM using delete command.

SQL> delete from hr.parent;

10000 rows deleted.

SQL> commit;

Commit complete.

PARENT table is always formed by 3 extents.

SQL> select count(*) from dba_extents
  2  where segment_name = 'PARENT';

  COUNT(*)
----------
         3

It's still not possible to truncate PARENT table...

SQL> truncate table hr.parent;
truncate table hr.parent
                  *
ERROR at line 1:
ORA-02266: unique/primary keys in table referenced by enabled foreign keys

... even when no rows are available and referenced.

SQL> select count(*) from hr.parent;

  COUNT(*)
----------
         0

SQL> select count(*) from hr.child;

  COUNT(*)
----------
         0

You can truncate PARENT table again only if foreign key is disabled

SQL> alter table hr.child modify constraint child_fk disable;

Table altered.

SQL> truncate table hr.parent;

Table truncated.

PARENT table is now formed by 1 extents.

SQL> select count(*) from dba_extents
  2  where segment_name = 'PARENT';

  COUNT(*)
----------
         1

If you want to see the extent allocated as soon as you create PARENT table, you have to use the "segment creation immediate" option on your create table statement.

SQL> drop table hr.child; 

Table dropped.

SQL> drop table hr.parent;

Table dropped.

SQL> create table hr.parent (a number) segment creation immediate;

Table created.

SQL> select count(*) from dba_extents
  2  where segment_name = 'PARENT';

  COUNT(*)
----------
         1

That's all.

How to recover a never backed up tablespace after losing its datafile and even the current controlfile after the autobackup feature completes its job

This post will take into consideration a Recovery Manager setting using the CONTROLFILE AUTOBACKUP feature, a tablespace created after the only available full backup (so this backup doesn't have information on this tablespace), some rows committed on the new tablespace, a crash happened after a backup of the current controlfile was completed.
This crash envolves the lost of the "never backed up" tablespace and of the current controlfile.

Let's start with an example. Our instance is up and running.

[oracle@localhost orcl]$ ps -ef | grep smon
oracle   13600     1  0 06:11 ?        00:00:00 ora_smon_orcl
oracle   13794 13766  0 06:24 pts/5    00:00:00 grep smon

Connect with RMAN client to see persistent settings.

[oracle@localhost orcl]$ rman target /

RMAN> show all;

using target database control file instead of recovery catalog
RMAN configuration parameters for database with db_unique_name ORCL are:
CONFIGURE RETENTION POLICY TO REDUNDANCY 1; # default
CONFIGURE BACKUP OPTIMIZATION ON;
CONFIGURE DEFAULT DEVICE TYPE TO DISK; # default
CONFIGURE CONTROLFILE AUTOBACKUP ON;
CONFIGURE CONTROLFILE AUTOBACKUP FORMAT FOR DEVICE TYPE DISK TO '%F'; # default
CONFIGURE DEVICE TYPE DISK BACKUP TYPE TO COMPRESSED BACKUPSET PARALLELISM 1;
CONFIGURE DATAFILE BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
CONFIGURE ARCHIVELOG BACKUP COPIES FOR DEVICE TYPE DISK TO 1; # default
CONFIGURE MAXSETSIZE TO UNLIMITED; # default
CONFIGURE ENCRYPTION FOR DATABASE OFF; # default
CONFIGURE ENCRYPTION ALGORITHM 'AES128'; # default
CONFIGURE COMPRESSION ALGORITHM 'HIGH' AS OF RELEASE 'DEFAULT' OPTIMIZE FOR LOAD TRUE;
CONFIGURE ARCHIVELOG DELETION POLICY TO NONE; # default
CONFIGURE SNAPSHOT CONTROLFILE NAME TO '/home/oracle/app/oracle/product/11.2.0/dbhome_2/dbs/snapcf_orcl.f'; # default

Connect with sqlplus client and (try to) drop the tablespace YYY including its contents and datafiles.

[oracle@localhost orcl]$ sqlplus / as sysdba

SQL> drop tablespace YYY including contents and datafiles;
drop tablespace YYY including contents and datafiles
*
ERROR at line 1:
ORA-00959: tablespace 'YYY' does not exist

Now delete all backups and copies. I want to be sure I don't have a valid backup of YYY tablespace.

[oracle@localhost orcl]$ rman target /

RMAN> delete noprompt backup;

using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=34 device type=DISK

List of Backup Pieces
BP Key  BS Key  Pc# Cp# Status      Device Type Piece Name
------- ------- --- --- ----------- ----------- ----------
139     138     1   1   AVAILABLE   DISK        /home/oracle/app/oracle/flash_recovery_area/ORCL/backupset/2012_11_27/o1_mf_annnn_TAG20121127T055405_8c9khy7t_.bkp
140     139     1   1   AVAILABLE   DISK        /home/oracle/app/oracle/flash_recovery_area/ORCL/autobackup/2012_11_27/o1_mf_s_800431150_8c9kshfg_.bkp
141     140     1   1   AVAILABLE   DISK        /home/oracle/app/oracle/flash_recovery_area/ORCL/backupset/2012_11_27/o1_mf_nnndf_TAG20121127T055407_8c9kj0ty_.bkp
142     141     1   1   AVAILABLE   DISK        /home/oracle/app/oracle/flash_recovery_area/ORCL/backupset/2012_11_27/o1_mf_annnn_TAG20121127T060546_8c9l5vgg_.bkp
143     142     1   1   AVAILABLE   DISK        /home/oracle/app/oracle/flash_recovery_area/ORCL/autobackup/2012_11_27/o1_mf_s_800432539_8c9m4wy1_.bkp
deleted backup piece
backup piece handle=/home/oracle/app/oracle/flash_recovery_area/ORCL/backupset/2012_11_27/o1_mf_annnn_TAG20121127T055405_8c9khy7t_.bkp RECID=139 STAMP=800430846
deleted backup piece
backup piece handle=/home/oracle/app/oracle/flash_recovery_area/ORCL/autobackup/2012_11_27/o1_mf_s_800431150_8c9kshfg_.bkp RECID=140 STAMP=800431151
deleted backup piece
backup piece handle=/home/oracle/app/oracle/flash_recovery_area/ORCL/backupset/2012_11_27/o1_mf_nnndf_TAG20121127T055407_8c9kj0ty_.bkp RECID=141 STAMP=800430848
deleted backup piece
backup piece handle=/home/oracle/app/oracle/flash_recovery_area/ORCL/backupset/2012_11_27/o1_mf_annnn_TAG20121127T060546_8c9l5vgg_.bkp RECID=142 STAMP=800431547
deleted backup piece
backup piece handle=/home/oracle/app/oracle/flash_recovery_area/ORCL/autobackup/2012_11_27/o1_mf_s_800432539_8c9m4wy1_.bkp RECID=143 STAMP=800432540
Deleted 5 objects

RMAN> delete noprompt copy;  

released channel: ORA_DISK_1
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=34 device type=DISK
specification does not match any datafile copy in the repository
specification does not match any control file copy in the repository
List of Archived Log Copies for database with db_unique_name ORCL
=====================================================================

Key     Thrd Seq     S Low Time           
------- ---- ------- - -------------------
159     1    6       A 27-11-2012 04:11:24
        Name: /home/oracle/app/oracle/flash_recovery_area/ORCL/archivelog/2012_11_27/o1_mf_1_6_8c9khxlq_.arc

168     1    7       A 27-11-2012 05:54:05
        Name: /home/oracle/app/oracle/flash_recovery_area/ORCL/archivelog/2012_11_27/o1_mf_1_7_8c9m31n0_.arc

160     1    7       A 27-11-2012 05:54:05
        Name: /home/oracle/app/oracle/flash_recovery_area/ORCL/archivelog/2012_11_27/o1_mf_1_7_8c9l5tb5_.arc

169     1    8       A 27-11-2012 06:05:46
        Name: /home/oracle/app/oracle/flash_recovery_area/ORCL/archivelog/2012_11_27/o1_mf_1_8_8c9m31rn_.arc

161     1    8       A 27-11-2012 06:05:46
        Name: /home/oracle/app/oracle/flash_recovery_area/ORCL/archivelog/2012_11_27/o1_mf_1_8_8c9lcht5_.arc

170     1    9       A 27-11-2012 06:08:47
        Name: /home/oracle/app/oracle/flash_recovery_area/ORCL/archivelog/2012_11_27/o1_mf_1_9_8c9m31yz_.arc

deleted archived log
archived log file name=/home/oracle/app/oracle/flash_recovery_area/ORCL/archivelog/2012_11_27/o1_mf_1_6_8c9khxlq_.arc RECID=159 STAMP=800430845
deleted archived log
archived log file name=/home/oracle/app/oracle/flash_recovery_area/ORCL/archivelog/2012_11_27/o1_mf_1_7_8c9m31n0_.arc RECID=168 STAMP=800432481
deleted archived log
archived log file name=/home/oracle/app/oracle/flash_recovery_area/ORCL/archivelog/2012_11_27/o1_mf_1_7_8c9l5tb5_.arc RECID=160 STAMP=800431546
deleted archived log
archived log file name=/home/oracle/app/oracle/flash_recovery_area/ORCL/archivelog/2012_11_27/o1_mf_1_8_8c9m31rn_.arc RECID=169 STAMP=800432481
deleted archived log
archived log file name=/home/oracle/app/oracle/flash_recovery_area/ORCL/archivelog/2012_11_27/o1_mf_1_8_8c9lcht5_.arc RECID=161 STAMP=800431979
deleted archived log
archived log file name=/home/oracle/app/oracle/flash_recovery_area/ORCL/archivelog/2012_11_27/o1_mf_1_9_8c9m31yz_.arc RECID=170 STAMP=800432482
Deleted 6 objects

Now it's time to take a full database backup including the archived redo log. This backup doesn't contain a tablespace named YYY.

RMAN> backup database plus archivelog;

Starting backup at 27-11-2012 06:25:54
current log archived
using channel ORA_DISK_1
channel ORA_DISK_1: starting compressed archived log backup set
channel ORA_DISK_1: specifying archived log(s) in backup set
input archived log thread=1 sequence=1 RECID=171 STAMP=800432754
channel ORA_DISK_1: starting piece 1 at 27-11-2012 06:25:54
channel ORA_DISK_1: finished piece 1 at 27-11-2012 06:25:55
piece handle=/home/oracle/app/oracle/flash_recovery_area/ORCL/backupset/2012_11_27/o1_mf_annnn_TAG20121127T062554_8c9mclss_.bkp tag=TAG20121127T062554 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:01
Finished backup at 27-11-2012 06:25:55

Starting backup at 27-11-2012 06:25:56
using channel ORA_DISK_1
channel ORA_DISK_1: starting compressed full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
input datafile file number=00002 name=/home/oracle/app/oracle/oradata/orcl/sysaux01.dbf
input datafile file number=00001 name=/home/oracle/app/oracle/oradata/orcl/system01.dbf
input datafile file number=00004 name=/home/oracle/app/oracle/oradata/orcl/users01.dbf
input datafile file number=00005 name=/home/oracle/app/oracle/oradata/orcl/example01.dbf
input datafile file number=00003 name=/home/oracle/app/oracle/oradata/orcl/undotbs01.dbf
input datafile file number=00006 name=/home/oracle/app/oracle/oradata/orcl/APEX_1930613455248703.dbf
input datafile file number=00007 name=/home/oracle/app/oracle/oradata/orcl/read_only01.dbf
input datafile file number=00009 name=/home/oracle/app/oracle/oradata/orcl/example02.dbf
channel ORA_DISK_1: starting piece 1 at 27-11-2012 06:25:56
channel ORA_DISK_1: finished piece 1 at 27-11-2012 06:36:22
piece handle=/home/oracle/app/oracle/flash_recovery_area/ORCL/backupset/2012_11_27/o1_mf_nnndf_TAG20121127T062556_8c9mcnw9_.bkp tag=TAG20121127T062556 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:10:26
Finished backup at 27-11-2012 06:36:22

Starting backup at 27-11-2012 06:36:22
current log archived
using channel ORA_DISK_1
channel ORA_DISK_1: starting compressed archived log backup set
channel ORA_DISK_1: specifying archived log(s) in backup set
input archived log thread=1 sequence=2 RECID=172 STAMP=800433383
channel ORA_DISK_1: starting piece 1 at 27-11-2012 06:36:23
channel ORA_DISK_1: finished piece 1 at 27-11-2012 06:36:25
piece handle=/home/oracle/app/oracle/flash_recovery_area/ORCL/backupset/2012_11_27/o1_mf_annnn_TAG20121127T063623_8c9mz80m_.bkp tag=TAG20121127T063623 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:02
Finished backup at 27-11-2012 06:36:25

Starting Control File and SPFILE Autobackup at 27-11-2012 06:36:25
piece handle=/home/oracle/app/oracle/flash_recovery_area/ORCL/autobackup/2012_11_27/o1_mf_s_800433385_8c9mz9sj_.bkp comment=NONE
Finished Control File and SPFILE Autobackup at 27-11-2012 06:36:28

My only current backup is formed by the following backup sets:

RMAN> list backup;

List of Backup Sets
===================

BS Key  Size       Device Type Elapsed Time Completion Time    
------- ---------- ----------- ------------ -------------------
143     247.00K    DISK        00:00:00     27-11-2012 06:25:54
        BP Key: 144   Status: AVAILABLE  Compressed: YES  Tag: TAG20121127T062554
        Piece Name: /home/oracle/app/oracle/flash_recovery_area/ORCL/backupset/2012_11_27/o1_mf_annnn_TAG20121127T062554_8c9mclss_.bkp

  List of Archived Logs in backup set 143
  Thrd Seq     Low SCN    Low Time            Next SCN   Next Time
  ---- ------- ---------- ------------------- ---------- ---------
  1    1       14560297   27-11-2012 06:21:21 14560798   27-11-2012 06:25:54

BS Key  Type LV Size       Device Type Elapsed Time Completion Time    
------- ---- -- ---------- ----------- ------------ -------------------
144     Full    9.45M      DISK        00:00:02     27-11-2012 06:31:37
        BP Key: 145   Status: AVAILABLE  Compressed: NO  Tag: TAG20121127T063135
        Piece Name: /home/oracle/app/oracle/flash_recovery_area/ORCL/autobackup/2012_11_27/o1_mf_s_800433095_8c9mp8mn_.bkp
  SPFILE Included: Modification time: 27-11-2012 06:12:53
  SPFILE db_unique_name: ORCL
  Control File Included: Ckp SCN: 14560974     Ckp time: 27-11-2012 06:31:35

BS Key  Type LV Size       Device Type Elapsed Time Completion Time    
------- ---- -- ---------- ----------- ------------ -------------------
145     Full    680.23M    DISK        00:10:18     27-11-2012 06:36:14
        BP Key: 146   Status: AVAILABLE  Compressed: YES  Tag: TAG20121127T062556
        Piece Name: /home/oracle/app/oracle/flash_recovery_area/ORCL/backupset/2012_11_27/o1_mf_nnndf_TAG20121127T062556_8c9mcnw9_.bkp
  List of Datafiles in backup set 145
  File LV Type Ckp SCN    Ckp Time            Name
  ---- -- ---- ---------- ------------------- ----
  1       Full 14560804   27-11-2012 06:25:56 /home/oracle/app/oracle/oradata/orcl/system01.dbf
  2       Full 14560804   27-11-2012 06:25:56 /home/oracle/app/oracle/oradata/orcl/sysaux01.dbf
  3       Full 14560804   27-11-2012 06:25:56 /home/oracle/app/oracle/oradata/orcl/undotbs01.dbf
  4       Full 14560804   27-11-2012 06:25:56 /home/oracle/app/oracle/oradata/orcl/users01.dbf
  5       Full 14560804   27-11-2012 06:25:56 /home/oracle/app/oracle/oradata/orcl/example01.dbf
  6       Full 14560804   27-11-2012 06:25:56 /home/oracle/app/oracle/oradata/orcl/APEX_1930613455248703.dbf
  7       Full 13915815   02-09-2012 22:03:34 /home/oracle/app/oracle/oradata/orcl/read_only01.dbf
  9       Full 14560804   27-11-2012 06:25:56 /home/oracle/app/oracle/oradata/orcl/example02.dbf

BS Key  Size       Device Type Elapsed Time Completion Time    
------- ---------- ----------- ------------ -------------------
146     224.00K    DISK        00:00:01     27-11-2012 06:36:24
        BP Key: 147   Status: AVAILABLE  Compressed: YES  Tag: TAG20121127T063623
        Piece Name: /home/oracle/app/oracle/flash_recovery_area/ORCL/backupset/2012_11_27/o1_mf_annnn_TAG20121127T063623_8c9mz80m_.bkp

  List of Archived Logs in backup set 146
  Thrd Seq     Low SCN    Low Time            Next SCN   Next Time
  ---- ------- ---------- ------------------- ---------- ---------
  1    2       14560798   27-11-2012 06:25:54 14561201   27-11-2012 06:36:23

BS Key  Type LV Size       Device Type Elapsed Time Completion Time    
------- ---- -- ---------- ----------- ------------ -------------------
147     Full    9.45M      DISK        00:00:01     27-11-2012 06:36:26
        BP Key: 148   Status: AVAILABLE  Compressed: NO  Tag: TAG20121127T063625
        Piece Name: /home/oracle/app/oracle/flash_recovery_area/ORCL/autobackup/2012_11_27/o1_mf_s_800433385_8c9mz9sj_.bkp
  SPFILE Included: Modification time: 27-11-2012 06:12:53
  SPFILE db_unique_name: ORCL
  Control File Included: Ckp SCN: 14561210     Ckp time: 27-11-2012 06:36:25

RMAN> list copy;  

specification does not match any datafile copy in the repository
specification does not match any control file copy in the repository
List of Archived Log Copies for database with db_unique_name ORCL
=====================================================================

Key     Thrd Seq     S Low Time           
------- ---- ------- - -------------------
171     1    1       A 27-11-2012 06:21:21
        Name: /home/oracle/app/oracle/flash_recovery_area/ORCL/archivelog/2012_11_27/o1_mf_1_1_8c9mcl8b_.arc

172     1    2       A 27-11-2012 06:25:54
        Name: /home/oracle/app/oracle/flash_recovery_area/ORCL/archivelog/2012_11_27/o1_mf_1_2_8c9mz7dq_.arc

I'm going to create the new YYY tablespace and a new table (IMPORTANT_YYY_TRANSACTION) containing some committed rows.

[oracle@localhost orcl]$ sqlplus / as sysdba

SQL>  create tablespace YYY DATAFILE '/home/oracle/app/oracle/oradata/orcl/tbs01.dbf' size 1M autoextend on next 1M maxsize 10M;

Tablespace created.

SQL> create table IMPORTANT_YYY_TRANSACTION (a number, b number) tablespace YYY;

Table created.

SQL> begin
    for indx IN 1 .. 1000
    loop
    execute immediate 'insert into IMPORTANT_YYY_TRANSACTION(a,b) values (:1, :2)' using indx, indx*2;
    end loop;
    commit;
    end;  2    3    4    5    6    7  
  8  /

PL/SQL procedure successfully completed.

SQL> alter system switch logfile;

System altered.

In Oracle Database 11gR2 the autobackup feature starts within a delay trying to encompass all of the structural changes made to the database rather than creating a new backup of the controlfile on each structural change. This delay could be critical for you and for your transactions and simply implies different ways to restore and recover them. Because I don't want to wait 5 minutes before autobackup controlfile feature starts and completes its job, I force the database to get a controlfile copy using RMAN. The important concept in this scenario is that I have a valid controlfile copy taken after the creation of a new and never backed up tablespace.

[oracle@localhost orcl]$ rman target /

RMAN> backup current controlfile;

Starting backup at 27-11-2012 06:50:02
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=48 device type=DISK
channel ORA_DISK_1: starting compressed full datafile backup set
channel ORA_DISK_1: specifying datafile(s) in backup set
including current control file in backup set
channel ORA_DISK_1: starting piece 1 at 27-11-2012 06:50:06
channel ORA_DISK_1: finished piece 1 at 27-11-2012 06:50:07
piece handle=/home/oracle/app/oracle/flash_recovery_area/ORCL/backupset/2012_11_27/o1_mf_ncnnf_TAG20121127T065003_8c9nryp2_.bkp tag=TAG20121127T065003 comment=NONE
channel ORA_DISK_1: backup set complete, elapsed time: 00:00:01
Finished backup at 27-11-2012 06:50:07

Starting Control File and SPFILE Autobackup at 27-11-2012 06:50:07
piece handle=/home/oracle/app/oracle/flash_recovery_area/ORCL/autobackup/2012_11_27/o1_mf_s_800434207_8c9ns04h_.bkp comment=NONE
Finished Control File and SPFILE Autobackup at 27-11-2012 06:50:08

Let's simulate a loss of our current controlfile and of our "never backed up" new tablespace (YYY).

[oracle@localhost orcl]$ mv control01.ctl control01.ctl.bck
[oracle@localhost orcl]$ mv /home/oracle/app/oracle/flash_recovery_area/orcl/control02.ctl /home/oracle/app/oracle/flash_recovery_area/orcl/control02.ctl.bck
[oracle@localhost orcl]$ mv tbs01.dbf tbs01.dbf.bck

The instance is still up and running

[oracle@localhost orcl]$ ps -ef|grep smon
oracle   13600     1  0 06:11 ?        00:00:01 ora_smon_orcl
oracle   14016 13766  1 06:50 pts/5    00:00:00 grep smon

I force the instance to abort

[oracle@localhost orcl]$ sqlplus / as sysdba

SQL> shutdown abort;
ORACLE instance shut down.

Let's try to recover our database. Connecting the RMAN client, the output log shows a "not started" instance.

[oracle@localhost orcl]$ rman target /

Recovery Manager: Release 11.2.0.2.0 - Production on Tue Nov 27 06:51:19 2012

Copyright (c) 1982, 2009, Oracle and/or its affiliates.  All rights reserved.

connected to target database (not started)

Let's start the instance in nomount mode.

RMAN> startup nomount;

Oracle instance started

Total System Global Area     456146944 bytes

Fixed Size                     1344840 bytes
Variable Size                394267320 bytes
Database Buffers              54525952 bytes
Redo Buffers                   6008832 bytes

We have lost our current controlfile and want to restore it using the autobackup feature. RMAN is able to search from the available backup set and find the right one, in my case it is able to use "o1_mf_s_800434207_8c9ns04h_.bkp" backup set

RMAN> restore controlfile from autobackup;

Starting restore at 27-11-2012 06:51:38
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=19 device type=DISK

recovery area destination: /home/oracle/app/oracle/flash_recovery_area
database name (or database unique name) used for search: ORCL
channel ORA_DISK_1: AUTOBACKUP /home/oracle/app/oracle/flash_recovery_area/ORCL/autobackup/2012_11_27/o1_mf_s_800434207_8c9ns04h_.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 /home/oracle/app/oracle/flash_recovery_area/ORCL/autobackup/2012_11_27/o1_mf_s_800434207_8c9ns04h_.bkp
channel ORA_DISK_1: control file restore from AUTOBACKUP complete
output file name=/home/oracle/app/oracle/oradata/orcl/control01.ctl
output file name=/home/oracle/app/oracle/flash_recovery_area/orcl/control02.ctl
Finished restore at 27-11-2012 06:51:44

The restored controlfile has references about YYY tablespace: that autobackup of the control file was created indeed after the creation of the lost tablespace.

[oracle@localhost orcl]$ strings /home/oracle/app/oracle/oradata/orcl/control01.ctl|grep -i YYY
YYY
YYY

Connect again with RMAN client to the "not mounted" instance.

[oracle@localhost orcl]$ rman target /

Recovery Manager: Release 11.2.0.2.0 - Production on Tue Nov 27 06:52:16 2012

Copyright (c) 1982, 2009, Oracle and/or its affiliates.  All rights reserved.

connected to target database: ORCL (not mounted)

A controlfile is now available to mount the instance.

RMAN> alter database mount;

using target database control file instead of recovery catalog
database mounted

The report schema command in "List of Permanent Datafiles" section has information about YYY tablespace and its datafile, even if it is not able to get the right size.

RMAN> report schema;

Starting implicit crosscheck backup at 27-11-2012 06:52:27
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=1 device type=DISK
Crosschecked 6 objects
Finished implicit crosscheck backup at 27-11-2012 06:52:29

Starting implicit crosscheck copy at 27-11-2012 06:52:29
using channel ORA_DISK_1
Finished implicit crosscheck copy at 27-11-2012 06:52:29

searching for all files in the recovery area
cataloging files...
cataloging done

List of Cataloged Files
=======================
File Name: /home/oracle/app/oracle/flash_recovery_area/ORCL/autobackup/2012_07_21/o1_mf_s_789203952_80ogm1c3_.bkp
File Name: /home/oracle/app/oracle/flash_recovery_area/ORCL/autobackup/2012_07_21/o1_mf_s_789209074_80omm3d0_.bkp
File Name: /home/oracle/app/oracle/flash_recovery_area/ORCL/autobackup/2012_11_27/o1_mf_s_800431548_8c9l5xbv_.bkp
File Name: /home/oracle/app/oracle/flash_recovery_area/ORCL/autobackup/2012_11_27/o1_mf_s_800434207_8c9ns04h_.bkp
File Name: /home/oracle/app/oracle/flash_recovery_area/ORCL/autobackup/2012_10_05/o1_mf_s_795852591_86xq10nr_.bkp
File Name: /home/oracle/app/oracle/flash_recovery_area/ORCL/autobackup/2012_10_05/o1_mf_s_795834324_86x564xb_.bkp
File Name: /home/oracle/app/oracle/flash_recovery_area/ORCL/autobackup/2012_09_26/o1_mf_s_795045371_867q3d12_.bkp
File Name: /home/oracle/app/oracle/flash_recovery_area/ORCL/autobackup/2012_07_17/o1_mf_s_788864449_80c39jlo_.bkp
File Name: /home/oracle/app/oracle/flash_recovery_area/ORCL/autobackup/2012_11_23/o1_mf_s_800101490_8bzkk05s_.bkp

RMAN-06139: WARNING: control file is not current for REPORT SCHEMA
Report of database schema for database with db_unique_name ORCL

List of Permanent Datafiles
===========================
File Size(MB) Tablespace           RB segs Datafile Name
---- -------- -------------------- ------- ------------------------
1    911      SYSTEM               ***     /home/oracle/app/oracle/oradata/orcl/system01.dbf
2    1105     SYSAUX               ***     /home/oracle/app/oracle/oradata/orcl/sysaux01.dbf
3    65       UNDOTBS1             ***     /home/oracle/app/oracle/oradata/orcl/undotbs01.dbf
4    225      USERS                ***     /home/oracle/app/oracle/oradata/orcl/users01.dbf
5    82       EXAMPLE              ***     /home/oracle/app/oracle/oradata/orcl/example01.dbf
6    7        APEX_1930613455248703 ***     /home/oracle/app/oracle/oradata/orcl/APEX_1930613455248703.dbf
7    1        READ_ONLY            ***     /home/oracle/app/oracle/oradata/orcl/read_only01.dbf
8    0        YYY                ***     /home/oracle/app/oracle/oradata/orcl/tbs01.dbf
9    1        EXAMPLE2             ***     /home/oracle/app/oracle/oradata/orcl/example02.dbf

List of Temporary Files
=======================
File Size(MB) Tablespace           Maxsize(MB) Tempfile Name
---- -------- -------------------- ----------- --------------------
1    20       TEMP                 32767       /home/oracle/app/oracle/oradata/orcl/temp01.dbf
2    20       TEMP                 50          /home/oracle/app/oracle/oradata/orcl/temp02.dbf

It's now possible to restore YYY tablespace

RMAN> restore tablespace YYY;

Starting restore at 27-11-2012 06:52:43
using channel ORA_DISK_1

creating datafile file number=8 name=/home/oracle/app/oracle/oradata/orcl/tbs01.dbf
restore not done; all files read only, offline, or already restored
Finished restore at 27-11-2012 06:52:43

On my local directory "tbs01.dbf" datafile is created.

[oracle@localhost orcl]$ ll -lrt
total 2825100
-rw-rw---- 1 oracle oracle    1056768 Sep  3 22:00 read_only01.dbf
drwxrwxr-x 2 oracle oracle       4096 Nov  9 07:51 non_default_location
-rw-rw---- 1 oracle oracle   20979712 Nov 27 02:47 temp02.dbf
-rw-rw---- 1 oracle oracle   20979712 Nov 27 06:25 temp01.dbf
-rw-rw---- 1 oracle oracle   52429312 Nov 27 06:36 redo02.log
-rw-rw---- 1 oracle oracle   52429312 Nov 27 06:36 redo02b.log
-rw-rw---- 1 oracle oracle  235937792 Nov 27 06:40 users01.dbf
-rw-rw---- 1 oracle oracle    1056768 Nov 27 06:40 example02.dbf
-rw-rw---- 1 oracle oracle   85991424 Nov 27 06:40 example01.dbf
-rw-rw---- 1 oracle oracle    7348224 Nov 27 06:40 APEX_1930613455248703.dbf
-rw-rw---- 1 oracle oracle    1056768 Nov 27 06:48 tbs01.dbf.bck
-rw-rw---- 1 oracle oracle   52429312 Nov 27 06:49 redo03.log
-rw-rw---- 1 oracle oracle   52429312 Nov 27 06:49 redo03b.log
-rw-rw---- 1 oracle oracle   68165632 Nov 27 06:50 undotbs01.dbf
-rw-rw---- 1 oracle oracle  955260928 Nov 27 06:50 system01.dbf
-rw-rw---- 1 oracle oracle 1158684672 Nov 27 06:50 sysaux01.dbf
-rw-rw---- 1 oracle oracle   52429312 Nov 27 06:50 redo01.log
-rw-rw---- 1 oracle oracle   52429312 Nov 27 06:50 redo01b.log
-rw-rw---- 1 oracle oracle    9846784 Nov 27 06:51 control01.ctl.bck
-rw-rw---- 1 oracle oracle    1056768 Nov 27 06:52 tbs01.dbf
-rw-rw---- 1 oracle oracle    9846784 Nov 27 06:52 control01.ctl

At this step you cannot directly recover your tablespace as the "RMAN-06067: RECOVER DATABASE required with a backup or created control file" error suggests.

[oracle@localhost orcl]$ rman target /

Recovery Manager: Release 11.2.0.2.0 - Production on Tue Nov 27 06:52:59 2012

Copyright (c) 1982, 2009, Oracle and/or its affiliates.  All rights reserved.

connected to target database: ORCL (DBID=1229390655, not open)

RMAN> recover tablespace YYY;

Starting recover at 27-11-2012 06:53:09
using target database control file instead of recovery catalog
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=19 device type=DISK

RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of recover command at 11/27/2012 06:53:11
RMAN-06067: RECOVER DATABASE required with a backup or created control file

You have to recover the entire database...

RMAN> recover database;

Starting recover at 27-11-2012 06:53:17
using channel ORA_DISK_1
datafile 7 not processed because file is read-only

starting media recovery

archived log for thread 1 with sequence 3 is already on disk as file /home/oracle/app/oracle/flash_recovery_area/ORCL/archivelog/2012_11_27/o1_mf_1_3_8c9nr8rf_.arc
archived log for thread 1 with sequence 4 is already on disk as file /home/oracle/app/oracle/oradata/orcl/redo01.log
archived log file name=/home/oracle/app/oracle/flash_recovery_area/ORCL/archivelog/2012_11_27/o1_mf_1_3_8c9nr8rf_.arc thread=1 sequence=3
archived log file name=/home/oracle/app/oracle/oradata/orcl/redo01.log thread=1 sequence=4
media recovery complete, elapsed time: 00:00:00
Finished recover at 27-11-2012 06:53:18

...and finally open it with the resetlogs option

RMAN> alter database open resetlogs;

database opened

All previous data inserted and committed into IMPORTANT_YYY_TRANSACTION table are available again.

[oracle@localhost orcl]$ sqlplus / as sysdba

SQL> select count(*) from IMPORTANT_YYY_TRANSACTION;

  COUNT(*)
----------
      1000

SQL> 

That's all.