[Monotone-devel] Re: netsync question

[Bruce Stephens]

Markus Schiltknecht <address@hidden> writes:

> I'm trying to understand netsync and all the 'how-to-store-deltas'
> question.
>
> In the wiki as well as in some IRC logs it's taken as a fact that
> netsync has to use forward-deltas. Why is that? I can't find a good
> reason for not using backwards-deltas in netsync. It seems to even have
> some benefits, like the ability of pulling only the head(s) of a branch.

Well, you couldn't use *only* backward deltas.  If you've got
A->B->C->D and you want to send that to someone who's got A, it's no
good just sending the backward deltas D->C, C->B, B->A.  

You could send the full text of D, and the backward deltas.  Or, I
guess, send the constructed A->D and the backward deltas.

That would have the disadvantage that it would be an all-or-nothing
operation: if the connection died, or there was some verification
error, then you'd end up with nothing.