Data recovery in IBM Database 2

This paper presents the various forms of data recovery provided by IBM Database 2 (DB2). It describes the DB2 recovery log, introduces the notion of a unit of recovery, and discusses the two-phase commit protocol used by DB2. Furthermore, it describes what type of information is logged, the DB2 checkpoint process, what a compensation log record is, and how DB2 handles undo/redo processing, media recovery, restart after abnormal system termination, and data unavailability.