@Override
  public RangeResponse isTxnRangeValid(long minTxnId, long maxTxnId) {
    // check the easy cases first
    if (minTxnId > highWatermark) {
      return RangeResponse.NONE;
    } else if (exceptions.length > 0 && exceptions[0] > maxTxnId) {
      return RangeResponse.ALL;
    }

    // since the exceptions and the range in question overlap, count the
    // exceptions in the range
    long count = Math.max(0, maxTxnId - highWatermark);
    for(long txn: exceptions) {
      if (minTxnId <= txn && txn <= maxTxnId) {
        count += 1;
      }
    }

    if (count == 0) {
      return RangeResponse.ALL;
    } else if (count == (maxTxnId - minTxnId + 1)) {
      return RangeResponse.NONE;
    } else {
      return RangeResponse.SOME;
    }
  }
Used if there are no open transactions in the snapshot
storage-api/src/java/org/apache/hadoop/hive/common/ValidReadTxnList.java