What will happen if a redo log file group is lost?
Losing an Inactive Online Redo Log Group LGWR can reuse the redo log group when required. The damaged inactive online redo log group eventually halts normal database operation. Reinitialize the damaged group manually by issuing the ALTER DATABASE CLEAR LOGFILE statement as described in this section.
What does redo log file contains?
The most crucial structure for recovery operations is the redo log, which consists of two or more preallocated files that store all changes made to the database as they occur. Every instance of an Oracle Database has an associated redo log to protect the database in case of an instance failure.
How do I recover a corrupt redo log file?
If the corrupt redo log file has not been archived, use the UNARCHIVED keyword in the statement. ALTER DATABASE CLEAR UNARCHIVED LOGFILE GROUP 3; This statement clears the corrupted redo logs and avoids archiving them. The cleared redo logs are available for use even though they were not archived.
Can we drop active redo log group?
You can drop a redo log member only if it is not part of an active or current group. If you want to drop a member of an active group, first force a log switch to occur. Make sure the group to which a redo log member belongs is archived (if archiving is enabled) before dropping the member.
How many redo log groups are required by Oracle?
two groups
An instance requires at least two groups of redo log files, regardless of the number of members in the groups. (A group comprises one or more members.) You can drop a redo log group only if it is inactive.
Can we delete redo log files?
It is permissible to drop redo log files so that a multiplexed redo log becomes temporarily asymmetric. For example, if you use duplexed groups of redo log files, you can drop one member of one group, even though all other groups have two members each.
How do you add more redo log groups?
To create a new group of redo log files, use the SQL statement ALTER DATABASE with the ADD LOGFILE clause. The following statement adds a new group of redo logs to the database: ALTER DATABASE ADD LOGFILE (‘/oracle/dbs/log1c.