---this happened when initially writing a symbol---

Traceback (most recent call last):
  ...
  File "myProgram.py", line 102, in saveData
    lib.write(key, df, {'start': data[0]['date'], 'end': data[len(data)-1]['date'] }, chunk_size=chunkSize)
  File ".../arctic/chunkstore/chunkstore.py", line 351, in write
    data = self.serializer.serialize(record)
  File ".../arctic/serialization/numpy_arrays.py", line 176, in serialize
    ret = self.converter.docify(df)
  File ".../arctic/serialization/numpy_arrays.py", line 115, in docify
    raise e
  File ".../arctic/serialization/numpy_arrays.py", line 106, in docify
    arr, mask = self._convert_types(df[c].values)
  File ".../arctic/serialization/numpy_arrays.py", line 82, in _convert_types
    return a.astype('U{:d}'.format(max_len)), mask
MemoryError


---another run, where this time the initial write succeeded, but updating it failed---


Traceback (most recent call last):
  ...
  File "myProgram.py", line 97, in saveData
    lib.append(key, getDataFrame(data[trimIndex:]), metadata)
  File ".../arctic/chunkstore/chunkstore.py", line 511, in append
    self.__update(sym, item, metadata=metadata, combine_method=SER_MAP[sym[SERIALIZER]].combine, audit=audit)
  File ".../arctic/chunkstore/chunkstore.py", line 427, in __update
    df = self.read(symbol, chunk_range=chunker.to_range(start, end), filter_data=False)
  File ".../arctic/chunkstore/chunkstore.py", line 284, in read
    return deser(chunks[symbol[0]], **kwargs) if skip_filter else chunker.filter(deser(chunks[symbol[0]], **kwargs), chunk_range)
  File ".../arctic/serialization/numpy_arrays.py", line 210, in deserialize
    df = pd.concat([self.converter.objify(d, columns) for d in data], ignore_index=not index)
  File ".../arctic/serialization/numpy_arrays.py", line 210, in <listcomp>
    df = pd.concat([self.converter.objify(d, columns) for d in data], ignore_index=not index)
  File ".../arctic/serialization/numpy_arrays.py", line 141, in objify
    d = decompress(doc[DATA][doc[METADATA][LENGTHS][col][0]: doc[METADATA][LENGTHS][col][1] + 1])
  File ".../arctic/_compression.py", line 55, in decompress
    return clz4.decompress(_str)
  File "src/_compress.pyx", line 121, in _compress.decompress
Exception: Error decompressing