Restart Algorithm (rev 3)
Starting with the last checkpoint, scan forward in the log.
- Maintain list of active transactions (initialized to content of checkpoint record).
- Redo an update record U for page P only if LSN(P) < LSN(U).
- After you’re done scanning, abort all active transactions. Log undos while aborting. Log an abort record when you’re done aborting.
This style of record logging, logging undo’s, and replaying history during restart was popularized in the ARIES algorithm by Mohan et al at IBM.