Stuck Holding The Locks

One coordinator, three participants, one distributed transaction over 2PC. The coordinator is a single process with a local transaction log.

t	coordinator	P1	P2	P3
1	sends `PREPARE` to all	idle	idle	idle
2	collecting votes	logs `PREPARED`, holds locks, votes yes	logs `PREPARED`, holds locks, votes yes	logs `PREPARED`, holds locks, votes yes
3	writes `COMMIT` to its own log	prepared	prepared	prepared
4	process killed before any `COMMIT` is sent	prepared	prepared	prepared

The coordinator will be down for the next 40 minutes. What may the three participants legitimately do in the meantime?

Promote P1 to coordinator and re-run the prepare phase, so the surviving participants converge on a decision without the original coordinator.

Nothing but wait, still holding their locks. A yes vote is a promise, so none of them may decide unilaterally, and none of them knows the outcome, so talking to each other does not resolve it either.

Time out and abort. No decision arrived within the protocol's window, and abort is the safe default when the outcome is unknown.

Commit. Each one has a durable PREPARED record, and a participant that voted yes has by definition already validated everything the commit needs.