A9Sagas: multi-step work that fails halfway

The problem

1 s on screen = 100 ms

Payment went through, then shipping failed. Who gives the money back?

Three steps, nothing put back

Each order takes the payment, then reserves the stock, then books the shipping, in three services. Shipping fails now and then.

Live metrics for each version of the scene
Metric	No undo	A saga	Change
	0	0	—
	—	—	—
	—	—	—
target ≤ 400 ms	—	—	—

A9Sagas: multi-step work that fails halfway

An order touches payment, stock and shipping. If the third step fails, the first two must be undone.