Bazaar repository size benchmarks

[Jason Earl]

"Pieter de Bie" <frimmirf at gmail.com> writes:

> On Tue, Jun 3, 2008 at 1:56 PM, Ian Clatworthy
> <ian.clatworthy at internode.on.net> wrote:
>
>> I'm sure your benchmarking was sound but I'm curious about a few of
>> the results. The Mozilla benchmark doesn't gel with the figures given
>> in http://www.infoq.com/articles/dvcs-guide. Any ideas why? I'd also
>> like to know more about the heritage of the Emacs repo. Was it
>> converted by bzr-svn or by fastimport? The former uses a different
>> scheme for revision-ids. I wonder if bzr-fastexport/bzr-fastimport
>> would change the size or not?
>
> I have looked a bit at this. As for the Mozilla benchmark, I think
> that they might have used the cvs-trunk-import as opposed to the
> mozilla-central repository I used. This explains why they used "a
> snapshot of 12456 changesets (from 20080303, 70853 total revisions
> from the hg Repository)" whereas my mozilla-central repository is just
> 15000 revisions with full history.
>
> The reason the Mercurial size is so high is perhaps because they did
> something equivalent to "hg uncommit", which did not decrease
> repository size. Bazaar imported only the 12456 changesets, thereby
> giving a lower repository size than the Mercurial one. For the Git
> import, they did a repack, but not one quite as aggressive as mine
> (which really makes a difference after using git-fast-import), which
> explains the relatively high repository size for Git.
>
> For the Emacs repository, I used the Bazaar repository that is
> available here: http://bzr.notengoamigos.org. In retrospect, I don't
> know if the choice for Emacs was good, as this is just a cvs import
> and does not contain any branching / merging or rename tracking, which
> might influence the results. I wanted to put a really large repository
> in the test, but Emacs might not have been the right choice. Also, I
> don't know how this repository was created

I'm the guy that did the Emacs repository conversion, and I would
strongly advise against using it in any sort of benchmark.  It's not a
very good conversion, and I would bet that you would have a very hard
time getting something equivalent for the other tools.

It was just a test to see what a conversion of Emacs to bzr *might* look
like.

Jason