private void initAllPageReaders(
      IChunkMetadata metadata, List<Statistics<? extends Serializable>> pageStats) {
    Supplier<TsBlock> tsBlockSupplier = new TsBlockSupplier();
    for (int pageIndex = 0; pageIndex < pageStats.size(); pageIndex++) {
      MemPageReader pageReader =
          new MemPageReader(
              tsBlockSupplier,
              pageIndex,
              metadata.getDataType(),
              metadata.getMeasurementUid(),
              pageStats.get(pageIndex),
              globalTimeFilter);
      this.pageReaderList.add(pageReader);
    }
  }
To read chunk data in memory.
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/storageengine/dataregion/read/reader/chunk/MemChunkReader.java