Re: [Gnu-arch-users] [BUG] FEATURE PLANS: "perfect" summary deltas

[Tom Lord]

    > From: Aaron Bentley <address@hidden>

    > Tom Lord wrote:

    > >    aaron's alternative idea (the "separate delta directory") also aims
    > >    to minimize roundtrips: just get a listing of that one directory
    > >    and now you know a big chunk of the graph.  First: I think it would
    > >    interact poorly with smart servers because a smart server may be
    > >    willing to offer up a complete graph of deltas (so, while we only
    > >    have one roundtrip, the bandwidth can start to look pretty
    > >    interesting in large versions).  

    > The archive.h-level stuff needs to be of the form "what are you willing 
    > to give me that can get me from here to here."  

It does not.  This has been discussed in the past.   Gah... I wish you
were near enough that we could sit down at a pub table with a sheet of
paper: I'm increasingly getting the impression that there's some
disconnect between us about builder issues that needs to be debugged.

In some cases a server may decide that the delta from X to Y is best
provided as a list of composable deltas, but their composition should
take place behind the archive.h scene.

I'll have more time to reply in depth later, I hope, but I thought I
should point out that you're on the wrong track from the start there.

In general, maybe this will help fix the bug:

Strictly _optimal_ revision building is _not_ the goal.

Expected-case building that is not horribly far off (same big-O) as
optimal building is the goal.   Arguably, we achieved that a long time
ago.   Therefore, expanding what's covered by "expected case" is
desirable, but not at the cost of lots of hair.   This isn't an area
where brute-force changes are called for.

-t