[Python-Dev] PEP 574 (pickle 5) implementation and backport available (original) (raw)

Ivan Pozdeev vano at mail.mipt.ru
Fri May 25 14:28:57 EDT 2018

On 25.05.2018 20:36, Raymond Hettinger wrote:

On May 24, 2018, at 10:57 AM, Antoine Pitrou <solipsis at pitrou.net> wrote:

While PEP 574 (pickle protocol 5 with out-of-band data) is still in draft status, I've made available an implementation in branch "pickle5" in my GitHub fork of CPython: https://github.com/pitrou/cpython/tree/pickle5 Also I've published an experimental backport on PyPI, for Python 3.6 and 3.7. This should help people play with the new API and features without having to compile Python: https://pypi.org/project/pickle5/ Any feedback is welcome. Thanks for doing this. Hope it isn't too late, but I would like to suggest that protocol 5 support fast compression by default. We normally pickle objects so that they can be transported (saved to a file or sent over a socket). Transport costs (reading and writing a file or socket) are generally proportional to size, so compression is likely to be a net win (much as it was for header compression in HTTP/2). The PEP lists compression as a possible a refinement only for large objects, but I expect is will be a win for most pickles to compress them in their entirety.

I would advise against that. Pickle format is unreadable as it is, compression will make it literally impossible to diagnose problems. Python supports transparent compression, e.g. with the 'zlib' codec.

Raymond

Python-Dev mailing list Python-Dev at python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/vano%40mail.mipt.ru

-- Regards, Ivan

More information about the Python-Dev mailing list