distributed-computingdistributed-systemconsensuspaxos

How can I understand "value" in bacis paxos


I am reading Lamport's Paxos Mode Simple, and I get confused with the meaning "value" here.

For example, Lamport says:

If a proposal with value v is chosen, then every higher-numbered proposal that is chosen has value v

I don't know what value v means here:

  1. Does it mean different value of a certain variable, such as variable x's value can be 1 or 42?
  2. Or is it something like one log entry in Raft, such as x=1 or y=42?

I think the first interpretion is right, and basic Paxos can't determine multiple values, it just Propose-Accept-Chosen, and the whole basic Paxos instance finishes its mission.

However, I am not for sure.


Solution

  • Your second interpretation is correct ("It's like one log entry in Raft").

    You are also correct that Basic Paxos can't choose multiple values, it just chooses one, like a single log entry in Raft. To choose a series of values you need to chain multiple Basic Paxos instances together, like in Multi-Paxos or Raft.