Prof. Tony Hoare(Microsoft Research, Cambridge)
A compensable transaction is a program that performs an action accompanied by a program that performs a compensation for that action. After completion of the action, a later call of the compensation will undo its effects, as far as possible. Long sequences of compensable transactions can be composed into a single long-running transaction, which is still compensable.
A long-running transaction is more general than the typical database transaction. It does not have to observe the criterion of independence, so it can communicate with its external environment, or even with the real world.
However, long-running transactions still observe the principle of atomicity: each transaction either succeeds as a whole, or fails as a whole, leaving the world in (nearly, but not exactly) the same state as it started in.
|Zeit:||Freitag, 14.07.2006, 14.00 Uhr|
|Ort:||Uni Saarbrücken, Gebäude E1 3, Hörsaal 2|