private void updateInputIndex(int i, long currentEndTime) {
    int size = inputTsBlocks[i].getPositionCount();
    while (inputIndex[i] < size
        && comparator.lessThan(inputTsBlocks[i].getTimeByIndex(inputIndex[i]), currentEndTime)) {
      inputIndex[i]++;
    }
  }
Indicate whether we found an empty child input in one loop
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/execution/operator/process/join/InnerTimeJoinOperator.java