From: Matt Mackall <mpm@selenic.com>
Date: Fri, 29 Apr 2005 16:52:32 GMT
Subject: Re: Mercurial 0.4b vs git patchbomb benchmark
Message-ID: <20050429165232.GV21897@waste.org>
In-Reply-To: <118833cc05042908181d09bdfd@mail.gmail.com>

On Fri, Apr 29, 2005 at 11:18:20AM -0400, Morten Welinder wrote:
> > I had three design goals. "disk space" wasn't one of them
> 
> And, if at some point it should become an issue, it's fixable. Since
> access to objects is fairly centralized and since they are
> immutable, it would be quite simple to move an arbitrary selection
> of the objects into some other storage form which could take
> similarities between objects into account.

This is not a fix, this is a band-aid. A fix is fitting all the data
in 10 times less space without sacrificing too much performance.

> So disk space and its cousin number-of-files are both when-and-if
> problems. And not scary ones at that.

But its sibling bandwidth _is_ a problem. The delta between 2.6.10 and
2.6.11 in git terms will be much larger than a _full kernel tarball_.
Simply checking in patch-2.6.11 on top of 2.6.10 as a single changeset
takes 41M. Break that into a thousand overlapping deltas (ie the way
it is actually done) and it will be much larger.

-- 
Mathematics is the supreme nostalgia of our time.