Vector clock

Common card · No. 407953

A vector clock is a data structure used for determining the partial ordering of events in a distributed system and detecting causality violations. Just as in Lamport timestamps, inter-process messages contain the state of the sending process's logical clock. A vector clock of a system of n processes is a vector (equivalently, a 1-dimensional array) of n logical clocks, one clock per process. Besides maintaining its own clock, every process also keeps track of the largest value of each of the other processes' clocks that it has so far been informed of. The clock updates proceed as follows, where V C i {\displaystyle VC_{i}} denotes the value of the vector clock maintained by process i {\displaystyle i} : Initially all clocks are zero. Each time a process experiences an internal event, it increments its own logical clock in the vector by one...

Read on Wikipedia · Image CC BY-SA 3.0