Avoiding Undo and Redo?
To avoid both undo and redo
- never flush uncommitted updates (to avoid undo), and
- flush all of T’s updates to the stable database before it commits (to avoid redo).
Thus, it requires installing all of a transaction’s updates into the stable database in one write to disk
It can be done, but it isn’t efficient for short transactions and record-level updates.
- We’ll show how in a moment