public Reindexing readReindexing(String cluster) {
        Reindexing reindexing = curator.getData(statusPath(cluster)).map(serializer::deserialize)
                                       .orElse(Reindexing.empty());
        log.log(Level.FINE, () -> "Read reindexing status '" + reindexing + "' from '" + statusPath(cluster) + "'");
        return reindexing;
    }
If no reindexing data exists (has been wiped), assume current ready documents are already done.
clustercontroller-reindexer/src/main/java/ai/vespa/reindexing/ReindexingCurator.java