@Override
    public ClusterTimeseries getClusterTimeseries(ApplicationId application, ClusterSpec.Id cluster) {
        return clusterTimeseries.computeIfAbsent(new Pair<>(application, cluster),
                                                 __ -> new ClusterTimeseries(cluster, new ArrayList<>()));
    }
Lock all access for now since we modify lists inside a map
node-repository/src/main/java/com/yahoo/vespa/hosted/provision/autoscale/MemoryMetricsDb.java