Pysync 2.24 release, was Re: rsync on OpenVMS

Donovan Baarda abo at
Sat Oct 18 15:06:08 EST 2003

On Tue, 2003-10-14 at 11:01, Donovan Baarda wrote:
> On Mon, 2003-10-13 at 13:00, John E. Malmberg wrote:
> > jw schultz wrote:
> > > On Sun, Oct 12, 2003 at 12:38:40AM -0400, John E. Malmberg wrote:
> > I have not heard of unison.  I have heard that pysync was successful in 
> > a limited test on OpenVMS.  As near as I can tell though the librsync it 
> > is based on is a bit out of date.
> Something possibly worth trying on it is psyco... it compiles python to
> native code on the fly using a simple "import psyco". Pure python is a
> bit slow compared to native C implementations, but psyco could help
> close the gap a bit.

Following up on this... I tried using psyco with python2.2 and it cut
the pysync tests on my machine from 21secs down to 14secs... that's a
33% speedup. In the past I'd tried using pyrex to speed things up with
no success. psyco not only gives a better boost, but is much easier to

> I haven't touched pysync for a while, but it should still work with the
> latest librsync as the API hasn't changed. If there are any problems,
> please let me know. I believe rdiff-backup also has a python wrapper for
> librsync that might be more advanced than the one in pysync.
> I have plans for both pysync and librsync, but I haven't worked on them
> much lately. I find I am mostly motivated by feedback from others when
> funding is not available :-)

This little bit of interest motivated me to have a look at it again, and
I've just released version 2.24. From it's NEWS:

Updates between release 2.16 and 2.24
  * Added TODO and NEWS files.
  * Changed to use psyco if available, giving a 33% speedup.
  * Updated to use librsync 0.9.6.
  * Changed to using a faster md4sum implementation based on the
  librsync implementation, modified to use the RSA API.
  * Added rollin/rollout support to historical
  * Minor cleanups to rollsum code.
  * Minor tweaks to handling of block fragment matching.

Donovan Baarda <abo at>

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