rystsov

// by default ballot has a form of a tuple (tick, node_id)

// so in this piece of code

appeal = casCmd.apply(function(state) {
    if (state.epoch == epoch) {
        state.requests = requests;
        state.epoch += 1;
    }
    return state;

rystsov

function write(key, value, prevEtag) {
  var etag = GUID.NewGuid();
  var record = { 
    prevEtag: prevEtag, 
    value: value, 
    etag: etag
  };
  log(`${DateTime.now()}: writing(${key}, ${record})`);
  db.updateWhen(key, record, x => x.etag == prevEtag);
  log(`${DateTime.now()}: written(${key}, ${record})`);

rystsov

function fixed_read(db, key) { 
  var value = db.read(key);
  while (true) {
    // If we try to write the read value then we
    const written = db.updateWhen(key, {
      predicate: `x => x.ver==${value.ver}`,
      value: { ver: value.ver+1, val: value.val} 
    });
    if (!written.isConflict) {
      // either succeed and return the just written value

rystsov

using System;
using System.Collections.Generic;

class Program
{
    static void Main(string[] args)
    {
        ForceVsIntelligence();
        Console.WriteLine("Intelligence won!");
    }

rystsov

let flag = true;
async function frozen(promise) {
    flag = await promise;
    console.info("done");
}
let complete = null;
frozen(new Promise((reply, reject) => {
    complete = reply;
}));
// you'll never see 'done'

rystsov

// Please read the following posts to understand this code:
//   - "How Paxos works"
//     http://rystsov.info/2015/09/16/how-paxos-works.html
//   - "Read write quorums in Paxos"
//     http://rystsov.info/2015/12/30/read-write-quorums.html
//   - "Best of both worlds: Raft's joint consensus + Single Decree Paxos"
//     http://rystsov.info/2016/01/05/raft-paxos.html

// 1. Leader Election (LE)

rystsov

function sign(value, general) {
  value.signOffs[general] = true;
  if (len(value.signOffs) == 2) {
    value.isSent = true;
  }
  return value;
}

function unsign(value, general) {
  if (value == null) {

rystsov

function FSM() {
  this.state = null;
  this.execute = function(action, msg) {
    this.state = action(this.state, msg)
  };
}

rystsov

def search(xs, b, e, x):
    if b==e:
        return b if xs[b] == x else -1
    m = (b+e)/2
    # [x_b .. x_m x_{m+1} .. x_e]
    # x_b <= x_m and x_{m+1} <= x_e # normal, normal
    if xs[b] <= xs[m] and xs[m+1] <= xs[e]:
        if xs[b] <= x <= xs[m]:
            return search(xs, b, m, x)
        if xs[m+1] <= x <= xs[e]:

rystsov

class Proposer:
    def __init__(self, nodes, q, node_id):
        self.q = q
        self.nodes = nodes
        self.node_id = node_id
    # generates a new ballot number which is greater than v
    def get_n(self, v):
        # ...
    @endpoint
    def change_query(self, change, query, due):