A more efficient up2date service using binary diffs

[Kyrre Ness Sjobak]

lør, 12.03.2005 kl. 15.43 skrev M A Young:
> On Fri, 11 Mar 2005, Jeff Johnson wrote:
> 
> > This patch
> >     https://svn.uhulinux.hu/packages/dev/zlib/patches/02-rsync.patch
> > is in rpm-4.4.1 and on by default.
> >
> > If the payloads in FC4 are not rsyncable right now, then it's because
> > beehive is using an
> > older version of rpm ... checking ... yep, current rpm payloads should
> > be rsync ready:
> >
> > $ rpm -q --qf '%{rpmversion}\n' perl
> > 4.4.1
> 
> It seems the option isn't active for FC3 and its updates (which is what I
> had tested) so I have repeated the test with a couple of RPMs from
> different rawhide mirrors using xdelta, which uses a similar algorithm to
> rsync, and found the following sizes
> 
> libgcj-4.0.0-0.31.i386.rpm 13942525
> libgcj-4.0.0-0.32.i386.rpm 13950302
> xdelta of rpms              6911651
> xdelta of header + cpio     3723074
> 
> thus there is a significent saving in size for small changes, though you
> can do even better with more processing. Also from my experience with
> openoffice rpm library rpms don't diff as well as other packages, so the
> typical saving might be better than this example.
> 
> 	Michael Young

Just wondering: Are you doing the diffs on the data the package
contains, or the compressed version of it?