presto-main/src/main/java/io/prestosql/execution/ClusterSizeMonitor.java/ClusterSizeMonitor/updateAllNodes
class ClusterSizeMonitor:    private synchronized void updateAllNodes(AllNodes allNodes)
    {
        if (includeCoordinator) {
            currentCount = allNodes.getActiveNodes().size();
        }
        else {
            currentCount = Sets.difference(allNodes.getActiveNodes(), allNodes.getActiveCoordinators()).size();
        }
        if (currentCount >= executionMinCount) {
            ImmutableList<SettableFuture<?>> listeners = ImmutableList.copyOf(futures);
            futures.clear();
            executor.submit(() -> listeners.forEach(listener -> listener.set(null)));
        }
    }