Usually, the leader of the multiple nodes serves the data; all read & write operations pass through the leader. This approach ensures that the served data acts like it is served from one node. There is a real-time guarantee for the data. The model is called strong consistency or linearizability.
The leader might not be a leader anymore when a request comes in. That’s why the leader always has to check if it is still a leader. Only then can it return data. That’s why this checking system adds time.
