private void getMemChunkHandleFromMemTable(
      IDeviceID deviceID,
      String measurementId,
      Map<String, List<IChunkMetadata>> chunkMetadataMap,
      Map<String, List<IChunkHandle>> memChunkHandleMap,
      List<TimeRange> deletionList) {

    WritableMemChunk memChunk =
        (WritableMemChunk) memTableMap.get(deviceID).getMemChunkMap().get(measurementId);

    long[] timestamps = memChunk.getFilteredTimestamp(deletionList);

    chunkMetadataMap
        .computeIfAbsent(measurementId, k -> new ArrayList<>())
        .add(
            buildChunkMetaDataForMemoryChunk(
                measurementId,
                timestamps[0],
                timestamps[timestamps.length - 1],
                Collections.emptyList()));
    memChunkHandleMap
        .computeIfAbsent(measurementId, k -> new ArrayList<>())
        .add(new MemChunkHandleImpl(deviceID, measurementId, timestamps));
  }
Create this MemChunk if it's not exist.

@param deviceId device id
@param schemaList measurement schemaList
@return this MemChunkGroup
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/storageengine/dataregion/memtable/AbstractMemTable.java