Phase getPhase() {
      Phase phase;
      if (copyStartTime == UNINITIALIZED_TIMESTAMP) {
        phase = Phase.PREPARE;
      } else if (commitStartTime == UNINITIALIZED_TIMESTAMP) {
        phase = Phase.COPY;
      } else if (cleanupStartTime == UNINITIALIZED_TIMESTAMP) {
        phase = Phase.COMMIT;
      } else if (cycleEndTime == UNINITIALIZED_TIMESTAMP) {
        phase = Phase.CLEANUP;
      } else {
        phase = Phase.DONE;
      }
      return phase;
    }
@return the current phase of this cycle of compaction.
ambry-store/src/main/java/com/github/ambry/store/CompactionLog.java