protected void appendOneRightRowWithEmptyLeft() {
    for (int i = 0; i < leftOutputSymbolIdx.length; i++) {
      ColumnBuilder columnBuilder = resultBuilder.getColumnBuilder(i);
      columnBuilder.appendNull();
    }

    appendRightBlockData(
        rightBlockList,
        rightBlockListIdx,
        rightIndex,
        leftOutputSymbolIdx,
        rightOutputSymbolIdx,
        resultBuilder);

    resultBuilder.declarePosition();
  }
@return true if current right block is consumed up
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/execution/operator/source/relational/AbstractMergeSortJoinOperator.java