Ansichtswechsel

Ansichtswechsel, also "view change" in English, is a term used in the field of distributed computing and consensus algorithms, particularly in the context of the Paxos and Raft algorithms. It refers to the process by which a node in a distributed system changes its perspective or opinion about the current state of the system, typically in response to new information or a failure in communication.

In Paxos, for example, an Ansichtswechsel occurs when a node receives a message that indicates a different leader or a different value for a particular proposal. The node then updates its internal state to reflect this new information and may take actions such as voting for the new proposal or requesting more information.

In Raft, an Ansichtswechsel is a more structured process. It occurs when a node transitions from being a follower to a candidate or from a candidate to a leader. This transition is triggered by a timeout or by receiving a message from another node that indicates a different term number or a different leader.

Ansichtswechsel is a critical aspect of fault tolerance in distributed systems. It allows the system to continue functioning correctly even in the presence of failures, by ensuring that all nodes have a consistent view of the system's state. However, it also introduces complexity, as the system must handle the potential for conflicting information and the need for nodes to update their state quickly and accurately.