Re: [darcs-devel] Re: Darcs-git pulling from the Linux repo: a Linux VM question

From: David Roundy <droundy@abridgegame.org>
Date: Apr 28, 2005, 11:39 UTC
Message-ID: <20050428113947.GC9422@abridgegame.org>
In-Reply-To: <Pine.LNX.4.58.0504270910510.18901@ppc970.osdl.org>

On Wed, Apr 27, 2005 at 09:16:03AM -0700, Linus Torvalds wrote:

Show 10 quoted lines

> On Wed, 27 Apr 2005, Juliusz Chroboczek wrote:
> > Here we're speaking about the initial import.  Committed on 17 April
> > 2005 by Linus Torvalds, with the comment ``Let it rip''.  220 MB of
> > changed files in a single commit.  2 minutes real time just to read
> > all the files, never mind doing anything useful with them.
> 
> I think you may well want to consider the initial commit special. In many 
> ways it is - it has no parents etc, so even apart from the fact that the 
> initial commit obviously tends to be a lot bigger than any other commit, 
> it actually fundamnetally is _technically_ different too.

This has been discussed, and while I'm not opposed to special-casing the initial commit, mostly we've taken the stance so far of not special-casing. It's much nicer if we can make darcs efficient enough to perform the initial commit without a special case, which has the nice side-effect of also improving other cases.

When we're desperate, we'll special-case the initial commit, but currently I'm sure we can pretty easily adjust things by making the git-tree-reading lazy, which should pretty well address both the memory and speed concerns--and also improve performance of other commands. Perhaps more to the point, it will also ensure that the same optimizations that work for working with darcs repos will help when dealing with git repos.

-- 
David Roundy
http://www.darcs.net