[Backup and recovery] restores damaged online redo log files.

Use the ALERTDATABASECLEARLOGFILEgroup #; command to delete existing log files (at least existing log files) and create new files. Only

Use the alert database clear logfile group #; command to delete existing log files (at least existing log files) and create new files. Only

Cause:

If the online redo log file is reused, the loss of a member in the log file will not cause the database to stop, but the alarm log will write a message indicating the problem.

Solution:

Method 1:

If you can tolerate the downtime, you can shut down the database and copy the damaged or lost members as the surviving members in the group. However, this operation is obviously inappropriate when the database remains open.

Disadvantage: downtime required

Method 2:

Use the alert database clear logfile group #; command to delete existing log files (at least existing log files) and create new files. The preceding operations can only be performed when these Log files are not active (you can use the Alter login e Switch Log command ). If you try to clear the current log file group or the previous log file group in the Active status, the system will receive an error message. In addition, if the database is in archivelog mode, the log file group must be archived.

Note:

When the database is opened, reusable online redo log files can be restored, so the database will not be shut down.