Logical clock
Encyclopedia
A logical clock is a mechanism for capturing chronological and causal relationships in a distributed system.
Logical clock algorithms of note are:
Logical clock algorithms of note are:
- Lamport timestampsLamport timestampsThe algorithm of Lamport timestamps is a simple algorithm used to determine the order of events in a distributed computer system. As different nodes or processes will typically not be perfectly synchronized, this algorithm is used to provide a partial ordering of events with minimal overhead, and...
, which are monotonically increasing software counters. - Vector clocksVector clocksVector clocks are an algorithm for generating a partial ordering of events in a distributed system and detecting causality violations. Just as in Lamport timestamps, interprocess messages contain the state of the sending process's logical clock...
, that allow for total ordering of events in a distributed system. - Version vectorVersion vectorA version vector is a mechanism for tracking changes to data in a distributed system, where multiple agents might update the data at different times. The version vector allows the participants to determine if one update preceded another , followed it, or if the two updates happened concurrently...
s, order replicas, according to updates, in an optimistic replicated system. - Matrix clocksMatrix clocksA matrix clock is a mechanism for capturing chronological and causal relationships in a distributed system.Matrix clocks are a generalization of the notion of vector clocks...
, an extension of vector clocks that also contains information about other processes' views of the system.