| How to recover a Redo.log file [message #61694] |
Tue, 18 May 2004 08:14  |
Nacho
Messages: 5
Registered: February 2002
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Junior Member |
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Hello,
I don't know why but I have lost one of my redo.log file and now the Database does not work.
Is it posible recover this file, I do not make a Back up 8(
Thanks
Regards
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| Re: How to recover a Redo.log file [message #61701 is a reply to message #61694] |
Tue, 18 May 2004 20:49  |
Daljit Singh
Messages: 290
Registered: October 2003
Location: Texas
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Senior Member |
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Hi,
First of all let me tell you one simple thing about the Database that the meaning of "I don't have any backup" is, you can't do anything.
But in your case if you lost any inactive redo log than you can simply recreate it. But if you lost an active or current log file than you have to recreate the controlfile and after that open the DB with resetlogs option.
Daljit Singh
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| Re: How to recover a Redo.log file [message #61704 is a reply to message #61703] |
Tue, 18 May 2004 23:27 |
Daljit Singh
Messages: 290
Registered: October 2003
Location: Texas
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Senior Member |
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Hi,
You can use ALTER DATABASE DROP LOGFILE GROUP (groupnumber) to drop a whole log group or you can use ALTER DATABASE DROP LOGFILE MEMBER 'FILE_PATH' to drop some specific log files. After dropping the missing log files/groups you can create new logfiles/groups by ALTER DATABASE ADD LOGFILE GROUP/MEMBER commands. Like
The following statement drops one redo log file member
ALTER DATABASE
DROP LOGFILE MEMBER 'd:oracleredoredo1.log';
The following statement drops all members of the redo log file group 3:
ALTER DATABASE DROP LOGFILE GROUP 3;
The following statement adds a redo log file group with two members and identifies it with a GROUP parameter value of 3:
ALTER DATABASE
ADD LOGFILE GROUP 3
('d:oracleredoredo1.log' ,
'd:oracleredoredo2.log') SIZE 50K;
The following statement adds a member to the redo log file group 3:
ALTER DATABASE
ADD LOGFILE MEMBER 'd:oracleredoredo2.log'
TO GROUP 3;
Daljit Singh.
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| Re: How to recover a Redo.log file [message #61716 is a reply to message #61694] |
Wed, 19 May 2004 22:04 |
Trifon Anguelov
Messages: 514
Registered: June 2002
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Senior Member |
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The method of recovery from loss of all members in an online log group depends on a number of factors, such as:
- The state of the database (open, crashed, closed cleanly, and so on)
- Whether the lost group was current
- Whether the lost group has been archived
For example:
- If you lose the current group, and the database is not closed cleanly (either it is open, or it has crashed), then you will have to restore an old backup and do point in time recovery, followed by open resetlogs. You will lose all transactions that were in the lost log.
- If you lose the current group, and the database is closed cleanly, you can open resetlogs with no transaction loss. You should immediately take a new full backup.
- If you lose a noncurrent group, you can use the 'alter database clear logfile' command to re-create all members in the group. No transactions are lost.
- If the group that you lost was archived before it was lost, nothing further is required. If the group was not archived, you should immediately take a new full backup.
Hope that helps,
clio_usa - OCP 8/8i/9i DBA
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