code: private Set<Dataset> getDatasetsWithThrowables() {
      Set<Dataset> datasetsWithThrowables = Sets.newHashSet();
      for (Dataset dataset : this.datasets) {
        if (!dataset.throwables().isEmpty()) {
          datasetsWithThrowables.add(dataset);
        }
      }
      return datasetsWithThrowables;
    }
docs: Return all {@link Dataset}s where a {@link Throwable} is thrown from the compaction job.