Revfile vs Atomicity & Dumbfs

[Matt Mackall]

On Mon, May 09, 2005 at 05:01:53PM -0500, John A Meinel wrote:
> I've been reading through the bzr docs, (I've gotten through the mailing
> lists, and I'm working on the inside documentation).
> 
> Generally, I like what I'm seeing, but I'm concerned about 2 things,
> both stemming from the same source.
> 
> Right now, I think you are just keeping a complete copy of each revision
> of a file, which you obviously don't want to do over time. The current
> suggestion is to use the "revfile" method, which has an append-only
> index and an append-only text store.
> 
> The thing is, append-only isn't very transaction safe, it's certainly
> better than write anywhere, but new-file only works better with backups,
> and atomicity. And unless I'm mistaken, it is easier to add a new file
> to a remote connection, than it is to append to an existing one (at
> least with sftp/ftp, webdav may be different).

Mercurial, which is where the revfile idea comes from, has a very
simple transaction and rollback scheme. Not sure how it interacts with
network protocols though. Mercurial treats network sources as
read-only.

-- 
Mathematics is the supreme nostalgia of our time.