Recoverable Schedules
Abort of T1 requires abort of T2!
- But T2 has already committed!
A recoverable schedule is one in
which this cannot happen.
- i.e. a Xact commits only after all the Xacts it “depends on” (i.e. it reads from or overwrites) commit.
- Recoverable implies ACA (but not vice-versa!).
Real systems typically ensure that only recoverable schedules arise (through locking).