During online logging, the undo log entries are managed. The modifying transactions store the undo log entries in undo log files.
Undo log management plays a part in the following actions:
· The database can create a transaction-consistent database state that reflects the state of the database system at the time of the last savepoint. The information in the undo log files is sufficient for this.
· In a restart or recovery, the required undo log entries are determined.
· For the database instance type liveCache, History Management is carried out for the undo log entries.