Old controfile during recovery

Question

Hi guys,
Lets say I am performing system copy and creating new controlfile from trace. What would happend if I accidently delete one datafile entry (lets say test.data1) from this trace and create controlfile from this trace? During controlfile creation no error occures as trace script does not know nothing that test.data1 should be included in controlfile. My question is: Would it be possible that I run recovery and get up database to open state ? And that the file test.data1 is totaly omitted from database?
Thanks a lot!

Answer 1

tdkuser wrote:
Hi guys,
Lets say I am performing system copy and creating new controlfile from trace. What would happend if I accidently >delete one datafile entry (lets say test.data1) from this trace and create controlfile from this trace?Dear tdkuser there nothing happen during creating controlfile.But when you try open database then you will see in alert.log some information related this datafile.Because in datadictionary actually there are information about this datafile ,however controlfile does not contain any information about this datafile(in this case that datafile called as missing datafile ).
During controlfile creation no error occures as trace script does not know nothing that test.data1 should be included in controlfile. My question is: Would it be possible that I run recovery and get up database to open state ? And that the file test.data1 is totaly omitted from database?
Thanks a lot!Yes you can recover this datafile while database is open state if this file physically exists in OS level and this datafile is not omitted from database.Finally you see that from below example.
SQL*Plus: Release 10.2.0.1.0 - Production on Thu Jul 8 20:14:48 2010
Copyright (c) 1982, 2005, Oracle.  All rights reserved.
Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Production
With the Partitioning, OLAP and Data Mining options
SQL> alter tablespace users add datafile
  2  'D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST\user02.dbf' size 10M;
Tablespace altered.
SQL> select name from v$datafile;
NAME
D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST\SYSTEM01.DBF
D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST\UNDOTBS01.DBF
D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST\SYSAUX01.DBF
D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST\USERS01.DBF
D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST\EXAMPLE01.DBF
D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST\USER02.DBF
6 rows selected.
SQL> alter database backup controlfile to trace as 'c:\c.txt';
alter database backup controlfile to trace as 'c:\c.txt'
ERROR at line 1:
ORA-01277: file 'C:\C.TXT' already exists
SQL> alter database backup controlfile to trace as 'c:\c.txt' reuse;
Database altered.
SQL> shutdown immediate;
Database closed.
Database dismounted.
ORACLE instance shut down.
SQL> startup nomount;
ORACLE instance started.
Total System Global Area  125829120 bytes
Fixed Size                  1247660 bytes
Variable Size              62916180 bytes
Database Buffers           58720256 bytes
Redo Buffers                2945024 bytes
SQL> CREATE CONTROLFILE REUSE DATABASE "TEST" NORESETLOGS  NOARCHIVELOG
  2      MAXLOGFILES 16
  3      MAXLOGMEMBERS 3
  4      MAXDATAFILES 100
  5      MAXINSTANCES 8
  6      MAXLOGHISTORY 292
  7  LOGFILE
  8    GROUP 1 'D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST\REDO01.LOG'  SIZE 50M,
  9    GROUP 2 'D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST\REDO02.LOG'  SIZE 50M,
10    GROUP 3 'D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST\REDO03.LOG'  SIZE 50M
11  DATAFILE
12    'D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST\SYSTEM01.DBF',
13    'D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST\UNDOTBS01.DBF',
14    'D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST\SYSAUX01.DBF',
15    'D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST\USERS01.DBF',
16    'D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST\EXAMPLE01.DBF';
Control file created.
SQL> desc v$recover_file;
Name                                      Null?    Type
FILE#                                              NUMBER
ONLINE                                             VARCHAR2(7)
ONLINE_STATUS                                      VARCHAR2(7)
ERROR                                              VARCHAR2(18)
CHANGE#                                            NUMBER
TIME                                               DATE
SQL> select file#,error from v$recover_file;
no rows selected
SQL> select name from v$datafile;
NAME
D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST\SYSTEM01.DBF
D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST\UNDOTBS01.DBF
D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST\SYSAUX01.DBF
D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST\USERS01.DBF
D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST\EXAMPLE01.DBF
SQL> alter database open;
Database altered.
SQL> select file#,error from v$recover_file;
     FILE# ERROR
         6 FILE MISSING
SQL> select name from v$datafile;
NAME
D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST\SYSTEM01.DBF
D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST\UNDOTBS01.DBF
D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST\SYSAUX01.DBF
D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST\USERS01.DBF
D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST\EXAMPLE01.DBF
D:\ORACLE\PRODUCT\10.2.0\DB_1\DATABASE\MISSING00006
6 rows selected.
SQL> alter database rename file 'D:\ORACLE\PRODUCT\10.2.0\DB_1\DATABASE\MISSING0
0006' to 'D:\oracle\product\10.2.0\oradata\TEST\USER02.DBF';
Database altered.
SQL> recover datafile 6;
Media recovery complete.
SQL> alter database datafile 6 online;
Database altered.
SQL> select name from v$datafile;
NAME
D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST\SYSTEM01.DBF
D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST\UNDOTBS01.DBF
D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST\SYSAUX01.DBF
D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST\USERS01.DBF
D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST\EXAMPLE01.DBF
D:\ORACLE\PRODUCT\10.2.0\ORADATA\TEST\USER02.DBF
6 rows selected.
SQL>