Lost committed Data

Question

I have done the following test and the following was the out come of it.. could anybody read this and explain what went wrong here.. and how can this happen with Oracle 11g R2_
[root@amil ~]# xhost +
access control disabled, clients can connect from any host
[root@amil ~]# su - oracle
[oracle@amil ~]$ dbca
[oracle@amil ~]$ export ORACLE_SID=test
[oracle@amil ~]$ sqlplus / as sysdba
SQL*Plus: Release 11.2.0.1.0 Production on Tue May 31 14:42:21 2011
Copyright (c) 1982, 2009, Oracle. All rights reserved.
Connected to:
Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
With the Partitioning, OLAP, Data Mining and Real Application Testing options
SQL> archive log list;
Database log mode Archive Mode
Automatic archival Enabled
Archive destination USE_DB_RECOVERY_FILE_DEST
Oldest online log sequence 21
Next log sequence to archive 23
Current log sequence 23
SQL> sho parameter db_flashback_retention
NAME TYPE VALUE
db_flashback_retention_target integer 1440
SQL> alter database flashback on;
Database altered.
SQL> desc v$logfile;
Name Null? Type
GROUP# NUMBER
STATUS VARCHAR2(7)
TYPE VARCHAR2(7)
MEMBER VARCHAR2(513)
IS_RECOVERY_DEST_FILE VARCHAR2(3)
SQL> select group#,status,member from v$logfile;
GROUP# STATUS
MEMBER
1
/u01/app/oracle/oradata/test/redo01.log
2
/u01/app/oracle/oradata/test/redo02.log
3
/u01/app/oracle/oradata/test/redo03.log
Then after I have deleted all the control files and redo log groups with OS commands and came back to sqlplus and did as follow:_
SQL> select group#,status,member from v$logfile;
GROUP# STATUS
MEMBER
1
/u01/app/oracle/oradata/test/redo01.log
2
/u01/app/oracle/oradata/test/redo02.log
3
/u01/app/oracle/oradata/test/redo03.log
SQL> select status from v$instance;
STATUS
OPEN
Next STRANGE thing was:_
SQL> alter system switch logfile;
System altered.
Still no error message triggered from the database !!!_
SQL> select group#,status,member from v$logfile;
GROUP# STATUS
MEMBER
1
/u01/app/oracle/oradata/test/redo01.log
2
/u01/app/oracle/oradata/test/redo02.log
3
/u01/app/oracle/oradata/test/redo03.log
SQL> select instance_name,status from v$instance;
INSTANCE_NAME STATUS
test OPEN
SQL> select instance_name,status from v$instance;
INSTANCE_NAME STATUS
test OPEN
SQL> alter system checkpoint;
System altered.
SQL> select instance_name,status from v$instance;
INSTANCE_NAME STATUS
test OPEN
SQL> alter system checkpoint;
System altered.
SQL> select instance_name,status from v$instance;
INSTANCE_NAME STATUS
test OPEN
SQL> alter system switch logfile;
System altered.
Strange !!!!_
SQL> alter system switch logfile;
alter system switch logfile
ERROR at line 1:
ORA-01013: user requested cancel of current operation
Now only it has detected the error and it is also after 15 or 20 minutes_
SQL> shutdown abort;
ORACLE instance shut down.
SQL> startup nomount
ORACLE instance started.
Total System Global Area 1023004672 bytes
Fixed Size 2219752 bytes
Variable Size 281018648 bytes
Database Buffers 734003200 bytes
Redo Buffers 5763072 bytes
SQL> alter database mount;
Database altered.
Af ter that I recover the database with RMAN
SQL> conn / as sysdba
Connected.
And Again I have tested the scenario in a different way:_
SQL> select instance_name,status from v$instance;
INSTANCE_NAME STATUS
test OPEN
Then again I delete all teh control files and all the redo log groups and did the following:_
SQL> alter system checkpoint;
System altered.
SQL> alter system checkpoint;
System altered.
SQL> alter system checkpoint;
system altered.
SQL> create table c1 (ci number);
Table created.
SQL> insert into c1 values (1);
1 row created.
SQL> commit;
Commit complete.
SQL> select * from c1;
CI
1
SQL> select instance_name,status from v$instance;
INSTANCE_NAME STATUS
test OPEN
SQL> update c1 set ci=5;
1 row updated.
SQL> commit;
Commit complete.
SQL> select * from c1;
CI
5
SQL> alter system checkpoint;
System altered.
SQL> alter system switch logfile;
System altered.
Still it is working without any errors !!!_
SQL> shutdown immediate;
ORA-00210: cannot open the specified control file
ORA-00202: control file: '/u01/app/oracle/oradata/test/control01.ctl'
ORA-27041: unable to open file
Linux-x86_64 Error: 2: No such file or directory
Additional information: 3
SQL>
SQL> shutdown abort;
ORACLE instance shut down.
SQL> startup nomount;
ORACLE instance started.
Total System Global Area 1023004672 bytes
Fixed Size 2219752 bytes
Variable Size 281018648 bytes
Database Buffers 734003200 bytes
Redo Buffers 5763072 bytes
SQL> alter database mount;
Database altered.
Then after I have performed a recovery..........!!_
SQL> select open_mode from v$database;
OPEN_MODE
READ WRITE
SQL> select * from c1;
select * from c1
ERROR at line 1:
ORA-00942: table or view does not exist
I lost committed Data !!!_
Edited by: Ora_Bunny on May 31, 2011 4:07 AM
Edited by: Ora_Bunny on May 31, 2011 4:21 AM
Edited by: Ora_Bunny on May 31, 2011 4:23 AM

Answer 1

And what did you expect when you delete all logfiles? Of course this will lead to the loss of committed data.
The phenomenon that the instance keeps on running for quite a while is because you are on *IX and only rm'd the files, so that the database still had a handle on them.
This was often reported from those B&R test cases. Better way to actually destroy the files is an
echo something > filenameKind regards
Uwe Hesse
http://uhesse.wordpress.com