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.