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Re: [Gnu-arch-users] Re: [BUG] FEATURE PLANS: "perfect" summary deltas
From: |
Aaron Bentley |
Subject: |
Re: [Gnu-arch-users] Re: [BUG] FEATURE PLANS: "perfect" summary deltas |
Date: |
Tue, 08 Jun 2004 10:23:25 -0400 |
User-agent: |
Mozilla Thunderbird 0.5 (X11/20040309) |
Tom Lord wrote:
If a log entry (the latest (or such) in the summary-delta branch)
becomes out-of-date because of deleted revisions, that means just one
extra roundtrip (to discover a revision has been deleted).
If the log data is sometimes wrong, I think I have to always verify it,
with the latency issues that implies. Whereas we can assume that the
directory listings aren't wrong, and don't need to be verified. (If
.listing files are wrong, that's an invalid archive) So I think "delta
directories" wins in that regard.
Yes, clearly. But your idea for generating deltas implies fairly
significant and uncertain changes to the builder whereas mine implies,
imo, fairly trivial and deterministic ones.
The changes you propose may be mathmatically simple, but I'm still
trying to sort out how to convince the builder to *backwards* in order
to go *forwards*. The whole algorithm could probably be built in, but
I'd rather build it out of smaller pieces, so it can use summary deltas
even if some are missing.
I have no problem making those special cases. I wonder if something
interesting can be done with them.
Perhaps they could be reserved for future "expansion" :-). Seriously,
removing those revisions would greatly reduce the space overhead for
archive owners and those who mirror them. Unless you can come up with
something uber-cool to do with them, I'd much prefer to see them gone.
I don't believe there's a fundamental difference between submission
branch revisions and external deltas. Naming conventions, of course,
will differ, but the changesets are the same, and the builder is
supposed to use any SUBMITQ candidates that are suitable, without
explicit user intervention. Supporting either will require the same
kinds of changes to the builder. In your feature plan for SUBMITQs,
you propose to make to make the builder unpredictable:
"... := randomly_choose (SUBMITQ-CANDIDATES)",
Even if you have the direct ancestor in a revlib, you're still forced to
use the SUBMITQ. Even SUBMITQ-IDEAL is far from ideal in that case.
Give me a way of determining file sizes and a directory of deltas, and I
can build you a builder that will never make *that* mistake.
I certainly don't want to implement submission branches that way
(using your "delta" directory). One way to understand the "point" of
a submission branch is that I should be able to "get-patch" the
changeset from it and it should represent a proposed divergence from
some mainline.
With external deltas, you could use 'tla delta' to get the same result,
with the same changesets downloaded. It would involve client-side
changeset generation, but perhaps we can special-case that away.
> A purely "commit --continuation" branch fits the bill
precisely --- all that's needed (at core) is to remove the restriction
that currently prohibits "commit --continuation" revisions.
Maybe that's the only core issue, but there are a number of others:
- builder changes
- branch-naming changes
- name-mangling
Aaron
- [Gnu-arch-users] Re: [BUG] FEATURE PLANS: "perfect" summary deltas, Aaron Bentley, 2004/06/03
- Re: [Gnu-arch-users] Re: [BUG] FEATURE PLANS: "perfect" summary deltas, Tom Lord, 2004/06/06
- Re: [Gnu-arch-users] Re: [BUG] FEATURE PLANS: "perfect" summary deltas, Aaron Bentley, 2004/06/06
- Re: [Gnu-arch-users] Re: [BUG] FEATURE PLANS: "perfect" summary deltas, Tom Lord, 2004/06/07
- Re: [Gnu-arch-users] Re: [BUG] FEATURE PLANS: "perfect" summary deltas, Aaron Bentley, 2004/06/07
- Re: [Gnu-arch-users] Re: [BUG] FEATURE PLANS: "perfect" summary deltas, Tom Lord, 2004/06/07
- Re: [Gnu-arch-users] Re: [BUG] FEATURE PLANS: "perfect" summary deltas,
Aaron Bentley <=
- Re: [Gnu-arch-users] Re: [BUG] FEATURE PLANS: "perfect" summary deltas, Tom Lord, 2004/06/14
- Re: [Gnu-arch-users] Re: [BUG] FEATURE PLANS: "perfect" summary deltas, Aaron Bentley, 2004/06/15
- Re: [Gnu-arch-users] Re: [BUG] FEATURE PLANS: "perfect" summary deltas, Tom Lord, 2004/06/15
- Re: [Gnu-arch-users] Re: [BUG] FEATURE PLANS: "perfect" summary deltas, Aaron Bentley, 2004/06/19
- Re: [Gnu-arch-users] Re: [BUG] FEATURE PLANS: "perfect" summary deltas, Andrew Suffield, 2004/06/19
- Re: [Gnu-arch-users] Re: [BUG] FEATURE PLANS: "perfect" summary deltas, Aaron Bentley, 2004/06/20
- Re: [Gnu-arch-users] Re: [BUG] FEATURE PLANS: "perfect" summary deltas, Tom Lord, 2004/06/21
- Re: [Gnu-arch-users] Re: [BUG] FEATURE PLANS: "perfect" summary deltas, Tom Lord, 2004/06/20
- Re: [Gnu-arch-users] Re: [BUG] FEATURE PLANS: "perfect" summary deltas, David Allouche, 2004/06/08