public TimeValuePair currentPoint() {
    if (currentPointElement == null) {
      // if the current point is overlapped with other pages, then get the highest priority point
      // from queue
      currentPoint = pointQueue.peek().timeValuePair;
      lastTime = currentPoint.getTimestamp();

      // fill aligned null value with the same timestamp
      if (isAligned) {
        fillAlignedNullValue();
      }
    }
    return currentPoint;
  }
This reader is used to deduplicate and organize overlapping pages, and read out points in order.
It is used for compaction.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/storageengine/dataregion/compaction/execute/utils/reader/PointPriorityReader.java