A more efficient up2date service using binary diffs

M A Young m.a.young at durham.ac.uk
Sat Mar 12 17:17:50 UTC 2005


On Sat, 12 Mar 2005, Kyrre Ness Sjobak wrote:

> lør, 12.03.2005 kl. 15.43 skrev M A Young:
> > 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
>
> Just wondering: Are you doing the diffs on the data the package
> contains, or the compressed version of it?

Both. The first figure is the xdelta of the raw rpms, without doing
anything to them, the second is the xdelta of the rpm header and
the uncompressed cpio archive concatenated together. Note that xdelta
compresses its result, with xdelta compression turned off, the sizes are

xdelta of rpms (no compression)    7025625
xdelta of header + cpio (no comp.) 8604163

	Michael Young




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