@TestOnly
  public void clear() {
    synchronized (timePartitionInfoMap) {
      timePartitionInfoMap.clear();
      timePartitionInfoMemoryBlock.setUsedMemoryInBytes(0L);
    }
  }
Manage all the time partitions for all data regions and control the total memory of them
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/storageengine/rescon/memory/TimePartitionManager.java