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Re: [Gnu-arch-users] [BUG] FEATURE PLANS: "perfect" summary deltas
From: |
Tom Lord |
Subject: |
Re: [Gnu-arch-users] [BUG] FEATURE PLANS: "perfect" summary deltas |
Date: |
Sat, 10 Jul 2004 15:02:24 -0700 (PDT) |
> 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
Re: [Gnu-arch-users] [BUG] FEATURE PLANS: "perfect" summary deltas, Aaron Bentley, 2004/07/10