[Monotone-devel] Re: moving forward on delta storage

[Lapo Luchini]

Nathaniel Smith <njs <at> pobox.com> writes:

> I wrote up a preliminary plan on what to do next on the delta storage
> stuff, i.e., make some comparisons:
>   http://venge.net/monotone/wiki/DeltaStorageStrategies/ShootOut

I *may* also be the right time to evaluate different binary-diff schemes?

bsdiff seems very promising to me, tough it is *very* memory-intensive (but we
could always switch to a "lower grade" binary diff on files that are too big, in
the worst case).

It was "strangely licensed" up to release 4.2, but 4.3 is covered by plain old
good BSD license.

http://www.daemonology.net/bsdiff/
regarding size: "bsdiff routinely produces binary patches 50-80% smaller than
those produced by Xdelta"
regarding memory: "bsdiff is quite memory-hungry. It requires
max(17*n,9*n+m)+O(1) bytes of memory, where n is the size of the old file and m
is the size of the new file. bspatch requires n+m+O(1) bytes."

    Lapo