protected boolean lessThan(
      TsBlock leftBlock,
      int[] leftPositions,
      int lIndex,
      TsBlock rightBlock,
      int[] rightPositions,
      int rIndex) {
    return examineLessThan(leftBlock, leftPositions, lIndex, rightBlock, rightPositions, rIndex);
  }
@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