If it works, the output looks will something Figure E: ORA-00279: change 38666 generated at 03/14/98 21:19:05 needed for thread 1. The redo log of a database consists of two or more redo log files. Tip Use the RMAN backup database plus archivelog command to ensure your current online redo log files (of all the threads) are switched and archived before and after the backup of the database. The "shell game" is covered in Step 3. SVRMGR > connect internal; Connected. Oracle also has the ability to recover parts of the database while other parts of the database are brought online. Losing all members of your current online redo log group is arguably the worst thing that can happen to your database. Export DBS="ENGDEV STAGE OTEST". For example, adding groups to a redo log can correct redo log group availability problems. When we refer to a damaged log group, we mean that all members of a log group are damaged. Try the following steps: First, make backup copies of all the files: $ cp /a/ /a/.
It is best if it is a cold backup after shutting down the database. If you clear a log file that is needed for recovery of a backup, then you can no longer recover from that backup. The redo log corruption could be any of these errors: ORA-16038 log%s sequence#%s cannot be archived. All rights reserved. Now attempt to do a startup mount: It appears that was a good copy of the control file. Since the database is now open, this can be done in one step, demonstrated in Figure G: SVRMGR > select file_name, tablespace_name from dba_data_files; FILE_NAME.
The only requirement for an instance redo log is that it have at least two groups. To find out if the control file is newer than the data files, try the following steps without overwriting the database files and see what happens. The online redo logs may not be dropped if: There are only two log groups. Before you execute check your archive log list (You will know the reason later on) and I am going to repeat the steps I mentioned above about corrupting the redo log file and then execute the command. The STATUS column in V$LOGFILE reports the status of the physical online redo log file member. Reason codes are as follows: 1) Failure trying to determine file block size. The first is if instructed to do so by Step 22. Wait a min I don't think we should be happy about it................. Let's take a look at the following steps to resolve these errors: Since we cannot startup database in current session, open another session and login as sys. If the database did not archive the bad log, use. 3 1 INACTIVE /u02/oraredo/O12C/ 50. Oracle Database uses the checksum to detect corruption in a redo log block. The following statement drops redo log group number 3: ALTER DATABASE DROP LOGFILE GROUP 3; When a redo log group is dropped from the database, and you are not using the Oracle-managed files feature, the operating system files are not deleted from disk. If the checkpoint is unsuccessful, then you will have to perform an incomplete recovery.
1. select * from v$log; alter system switch log file. Alter database add logfile group 1 ('/u001/app/oracle/oradata/redo/') size 512M; Happy learning!!! If all the redo logs in at least one group are damaged, and all the control files are damaged, proceed to Steps 23 and 24. Step 5: Connect to sys since you have shut down the instance. Steps for Renaming Redo Log Members. After processing an ASM-stored log, if the next log processed is not stored in ASM, mirroring can end with errors like Error 2919 jr_rac Jun 17, 2014 12:39:54 PM IBM InfoSphere Change Data Capture daemon has encountered an error message. And also database won't allow you to drop the redo log file whose status is CURRENT. If there are only one or two damaged data files, it's probably quicker to use the recover data file command. Look at each of the files shown by the above command. Each of the data files probably has the same modification time, or there might be a group of them with one modification time and another group with a different modification time.
And any other files I can't remember. Figure H: Readable listing of data files. For example, if you change a salary value in an employee table, you generate a redo record containing change vectors that describe changes to the data segment block for the table, the undo segment data block, and the transaction table of the undo segments. However, if any of this instance's online redo logs are damaged or missing, this option will not work. ORA-00202: controlfile: '/a/'. An inactive log group is one that is not being used by Oracle in any way. Using the BBED utility. Therefore, the online redo log is usually referred to as simply the redo log. If only one member of a multiplexed group has experienced a failure, then proceed to the section on "Restoring After Losing One Member of Multiplexed Group". Step 3: As mentioned earlier you won't see the error of corruption directly on the your screen. Follow the steps below, starting with restoring the control files from backup.
A redo record, also called a redo entry, is made up of a group of change vectors, each of which is a description of a change made to a single block in the database. This caused corruption in the current online redo log group. If the database did not open successfully, return to Step 1 and start over. Restore only the data files, not the control files.
Or why not run this command: The reason is: If the status of your redo log file is CURRENT then there is no archive log file created of that particular redo log file. I think that is due to redo log file damage. This is but one of the many reasons why a production instance should not be operating in no archive log mode. Also displays the status, which is CURRENT). The second configuration is illegal because it has only one group. The reason being you cannot just drop the redo log file if it's the single-lonely member in the group. As mentioned earlier, when recovering the database using a backup control file, it must be opened with the resetlogs option. Archived redo log files require disk space in the flash recovery area, and the flash recovery area requires monitoring to ensure that it does not fill completely. 0 MOUNTED SQL> recover database until cancel; ORA-00279:??? Issue an alter system checkpoint command to make the log group inactive. See Also:Oracle Database Reference for detailed information about these views.
Note: Perform a complete backup (including the control file) after executing the above command there is a chance to find a gap in the archivelog. Rather, the control files of the associated database are updated to drop the member from the database structure. If this'll work but is an option. Whenever a transaction is committed, LGWR writes the transaction redo records from the redo log buffer of the SGA to a redo log file, and assigns a system change number (SCN) to identify the redo records for each committed transaction. So, use the command with the. If Oracle encounters a damaged data file (whether or not it contains a rollback segment), it will complain about that data file and abort the attempt to open the database. It throws an error saying "cannot remove last log member" meaning you cannot drop redo log member if it is the only member remaining in the group. Hopefully your backup system has been running the backup control file to trace command on a regular basis.
Note:When you multiplex the redo log, the database must increase the amount of I/O that it performs. However, there is no advantage in varying file size between groups. Step 8: Restore Control Files and Prepare the Database for Recovery. How can I open the database? ARCHIVE_LAG_TARGET initialization parameter, you cause the database to examine the current redo log of the instance periodically. If the redo logs are all right, but all the control files are missing, proceed to Step 6. The following statement adds a new redo log member to redo log group number 2: ALTER DATABASE ADD LOGFILE MEMBER '/oracle/dbs/' TO GROUP 2; Notice that filenames must be specified, but sizes need not be. How much redo loss is tolerated in the standby database.
How do I repair redo log corruption? To restore, perform the following: - STARTUP MOUNT. Fixed component name. Failures with the online redo logs are rare, but when they do happen, you'll now be much better prepared to resolve any complications in an efficient and effective manner. Each database instance has its own redo log groups. Information in this document applies to any platform. After receiving the recover command, Oracle prompts for the name and location of the first archived redo log that it needs. Alter database clear unarchived logfile group