On Sun, Nov 14, 1999 at 11:40:19PM +0000, Russell G. Howe wrote: > I had this idea when I was sitting there watching 768K of package > listing for unstable trickle down my flaky, slow modem connection > at about 1K/sec, paying my 1 pence per minute to British Telecom > when I thought "Why can't I just download what's changed since > last time?". > > Now this seems like a great idea, although in practice it's not > that simple, but I think I've thought of a way that would not be > too difficult to do, and could (I think) be relatively easy to > implement (not that I'm up to the job). If the package listing was > archived, say, daily to a Packages-990103.gz file for instance. at > a set time (e.g. midnight GMT or whenever the servers are less > busy on average), and a backlog of diffs between these files kept > for, say, a month, then this would allow apt (assuming local time > and date were correct) to only grab the parts of the listing that > had changed, created by either diff or xdelta and put back > together by something like patch.
Sounds like a great idea to me. Something similar actually came up on debian-devel fairly recently (within the last couple of months), except that it was for binary diffs of packages--not package listings. IIRC, someone claimed to be tentatively working on that idea, so if you want to suggest yours to him or help him with it, have a look through the archives for his email address. One not-so-obvious (to me anyway) point that was mentioned was that you don't want to try diff'ing compressed files, since they're effectively completely random relative to each other. So you'd want to decompress them first. I just mention that in case you want to take a stab at implementing a trial version of this yourself. -Kevin
