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Re: [Gnu-arch-users] RFC: arch protocol, smart server, and tla implement
From: |
Colin Walters |
Subject: |
Re: [Gnu-arch-users] RFC: arch protocol, smart server, and tla implementation prototypes |
Date: |
Fri, 30 Jan 2004 18:02:47 -0500 |
On Fri, 2004-01-30 at 17:02, Aaron Bentley wrote:
> I disagree: solving the latency problem for archd is nice, but solving
> it for all protocols is nicer.
I don't see how it's possible for dumb-fs protocols.
> And I think we'll I'll get close to that
> functionality in the backwards-builder anyhow.
Backwards-building from a cacherev? But you still need to *find* that
cacherev, whether you work forwards or backwards, and that in general
involves traversing a bunch of revisions, with a roundtrip for each.
> Crossing tag boundaries will make the problem harder. While tla
> implicitly uses the call stack to build forwards, crossing tag
> boundaries requires tla to map out several paths, and determining the
> best one will require a cost assessment based on
>
> 1. aggregate download size
> 2. download cost for a given archive
How do you figure that out (efficiently)? I'm not sure you really can.
> The other advantage of allowing high performance with dumb servers is
> that smart servers may run out of CPU time and I/O bandwidth before they
> run out of network throughput.
I doubt that; as long as your server isn't trying to merge changesets
itself, etc., serving shouldn't be much more complicated than HTTP.
> Hmm. Looks awfully like streaming to me.
Well, I guess that's Tom's idea, to put the streaming inside each
command.
> I don't understand the motivation here. Is it to avoid biting off more
> than you can chew, bandwidth or storage-wise? (If so, wouldn't an
> Aggregate-size-limit header be better?)
Yeah, I don't understand that either.
> pfs-sftp, pfs-http, pfs-dav etc. can use arch_compose_changesets plus
> streaming or multiple simultaneous connections to implement
> arch_archive_delta.
dumb-fs level streaming might be possible per-protocol (I'm not sure if
sftp or http support that), but simultaneous connections would not be a
win. You still have to do at least one round-trip per connection, and
possibly more for authentication, etc.
> I think that archd might well be implemented at a higher level. It
> could conceivably use sftp, http, etc as backends.
Yeah, but why? The connection between archd and a dumb fs would likely
be just as slow.
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- Re: [Gnu-arch-users] RFC: arch protocol, smart server, and tla implementation prototypes, (continued)
- Re: [Gnu-arch-users] RFC: arch protocol, smart server, and tla implementation prototypes, Robert Collins, 2004/01/30
- Re: [Gnu-arch-users] RFC: arch protocol, smart server, and tla implementation prototypes, Andrew Suffield, 2004/01/30
- Re: [Gnu-arch-users] RFC: arch protocol, smart server, and tla implementation prototypes, Robert Collins, 2004/01/31
Re: [Gnu-arch-users] RFC: arch protocol, smart server, and tla implementation prototypes, Colin Walters, 2004/01/29
- Re: [Gnu-arch-users] RFC: arch protocol, smart server, and tla implementation prototypes, Tom Lord, 2004/01/30
- Re: [Gnu-arch-users] RFC: arch protocol, smart server, and tla implementation prototypes, Colin Walters, 2004/01/30
- Re: [Gnu-arch-users] RFC: arch protocol, smart server, and tla implementation prototypes, Tom Lord, 2004/01/30
- Re: [Gnu-arch-users] RFC: arch protocol, smart server, and tla implementation prototypes, Colin Walters, 2004/01/30
- Re: [Gnu-arch-users] RFC: arch protocol, smart server, and tla implementation prototypes, Tom Lord, 2004/01/30
Re: [Gnu-arch-users] RFC: arch protocol, smart server, and tla implementation prototypes, Aaron Bentley, 2004/01/30
Re: [Gnu-arch-users] RFC: arch protocol, smart server, and tla implementation prototypes,
Colin Walters <=
Re: [Gnu-arch-users] RFC: arch protocol, smart server, and tla implementation prototypes, Aaron Bentley, 2004/01/31
Re: [Gnu-arch-users] RFC: arch protocol, smart server, and tla implementation prototypes, Tom Lord, 2004/01/30
Re: [Gnu-arch-users] RFC: arch protocol, smart server, and tla implementation prototypes, Aaron Bentley, 2004/01/31
Re: [Gnu-arch-users] RFC: arch protocol, smart server, and tla implementation prototypes, Tom Lord, 2004/01/31
Re: [Gnu-arch-users] RFC: arch protocol, smart server, and tla implementation prototypes, Andrew Suffield, 2004/01/31
Re: [Gnu-arch-users] RFC: arch protocol, smart server, and tla implementation prototypes, Aaron Bentley, 2004/01/31
Re: [Gnu-arch-users] RFC: arch protocol, smart server, and tla implementation prototypes, Tom Lord, 2004/01/31
Re: [Gnu-arch-users] RFC: arch protocol, smart server, and tla implementation prototypes, Jason McCarty, 2004/01/31
Re: [Gnu-arch-users] RFC: arch protocol, smart server, and tla implementation prototypes, Aaron Bentley, 2004/01/31
Re: [Gnu-arch-users] RFC: arch protocol, smart server, and tla implementation prototypes, Aaron Bentley, 2004/01/31