private static List<Long> getCompactionBoundariesForMinor(CompactionWindow window,
    boolean singleOutput) {
    List<Long> boundaries = new ArrayList<>();
    boundaries.add(Long.MIN_VALUE);
    if (!singleOutput) {
      boundaries.add(window.startMillis());
    }
    return boundaries;
  }
Returns a list of boundaries for multiple compaction output from minTimestamp to maxTimestamp.
hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/compactions/DateTieredCompactionPolicy.java