Re: Cache Digests Diffs

On Fri, 16 Jul 1999, Kevin Littlejohn wrote:

> Given that cache A generated a digest (and the rsync signatures for the
> digest), it then transfers that first digest to it's neighbours, and holds
> only the signatures. When it comes to sending a diff, it uses the signatures,
> and it's own digest, to generate the diffs.
>
> Thus, no need for a second local copy to be held on the cache.

I see. Instead of keeping two digest copies (for a short time), you
propose to keep a single copy plus a signature (for a long time). This
will work, in principle, but it is not directly related to the original
problem of constructing a small diff.

I suspect that due to the nature of digest changes you will have to
either generate a lot of small blocks for your signature, or most blocks
will be marked as "modified". In either case you will face the
[original] problem of transferring a lot of information to the other
end.

However, I do not want to discourage you from trying. Perhaps I am
missing something again! Just implement/simulate your proposal and see
if it works better than what we have now. Moreover, you probably can use
rsync "as is" to see how big the diffs will be!

Thanks,

Alex.
Received on Tue Jul 29 2003 - 13:15:59 MDT