The online redo log files are a critical component in database recovery. Every transaction in the database updates the redo logs, regardless of whether archiving is enabled. During crash, instance, or media recovery, the database properly applies redo log files in ascending order by using the log sequence number of the necessary archived and redo log files.
If properly configured, the online redo logs require little maintenance. This section describes the more common redo log management tasks. It contains the following topics:
Note:
In a multitenant container database (CDB), Oracle Enterprise Manager Database Express (EM Express) provides online redo log file information only in the root, not in the pluggable databases (PDBs).