During online logging, the redo log entries are written and managed.
· Active components: Transactions in user tasks, log writer
· Storage units: log queue, log area
Redo log management plays a part in the following actions:
· During execution of a modifying transaction, the redo log entries are included in the log queue. The log writer writes the log pages from the log queue to the log area.
· During a log backup, information is obtained on whether entries from the log area are to be backed up, and if so, how many.
· For display on the monitor, information is obtained on waiting periods, and the type of access to the entries in the log queue.
· In the case of a restart or recovery, the required redo log entries are read from the log area.
· The database parameters and other internal information that controls logging are stored in the log area and updated at regular intervals.
In very special situations, you can deactivate redo log management temporarily.
See also: Log Settings