def iterator2dataframes(iterator, chunk_size: int):
      """Turn an iterator into multiple small pandas.DataFrame
      This is a balance between memory and efficiency"""
      records = []
      frames = []
      for i, record in enumerate(iterator):
          records.append(record)
          if i % chunk_size == chunk_size - 1:
              frames.append(pd.DataFrame(records))
              records = []
      if records:
          frames.append(pd.DataFrame(records))
      return pd.concat(frames)
    df = iterator2dataframes(cursor, 25000)