Paxos in Real Life
Let's look into some details on Paxos that are not covered in the original paper.
As we have seen so far, the Paxos protocol is well-specified. However, there are some small details and optimizations that the original paper could not cover. Some of these topics were covered in
. This lesson will cover some of these topics as briefly as possible. subsequent papers T. D. Chandra, R. Griesemer, and J. Redstone, “Paxos Made Live: An Engineering Perspective,” Proceedings of the Twenty-sixth Annual ACM Symposium on Principles of Distributed Computing, 2007.
Towards running multiple instances of Paxos
The basic Paxos protocol describes how a distributed system of multiple nodes can decide on a single value.
However, just choosing a single value would have limited practical applications on its own.
To build more useful systems, we need to be able to continuously select values.
This can be achieved by running multiple instances of Paxos, where an instance is an execution of the protocol that leads to a decision on a single value. These instances can run independently and in parallel, but they also have to be numbered.
Depending on the functionality needed, there can be several rules applied, such as not returning the result of an instance to the client, unless all the previous instances have been completed as well. ...