Vector Clocks

Vector clocks are used to compare distributed events by causal ancestry instead of assuming one global timeline. In a distributed system, it is difficult to maintain a perfectly synchronized physical clock. Vector clocks provide a way to establish a partial ordering of events in the system by tracking causal dependencies.

Experiment

Observe the behavior of vector clocks in different scenarios:

1. Select the Chain scenario. Click Finish to reveal all events. Observe that Event 4 (recv a by P₁) happens after Event 2 (send a by P₀) because its vector clock [2, 1, 0] is strictly greater than [2, 0, 0].
2. Select the Concurrent scenario. Click Finish. Compare Event 3 (send a by P₀) and Event 4 (send b by P₁). Their vector clocks are [2, 0, 0] and [0, 2, 0]. Since neither is strictly greater than the other, they are Concurrent.
3. Try the Fork join scenario and use the Step button to see how the vector clocks are updated event by event. Compare Event 1 and Event 6 to see causality.

Launch Experiment