@Override
  public void cleanupMemoryStorage() {
    TransientChangesIndexStorage<Key, Value> memStorage = (TransientChangesIndexStorage<Key, Value>)getStorage();
    //no synchronization on index write-lock, should be performed fast as possible since executed in write-action
    if (memStorage.clearMemoryMap()) {
      incrementModificationStamp();
    }
    memStorage.fireMemoryStorageCleared();
  }
@Override
  public void cleanupMemoryStorage()