BDFL decision of Python's DVCS

Andrew Bennetts andrew.bennetts at canonical.com
Wed Apr 1 23:57:53 BST 2009


Matthieu Moy wrote:
> Andrew Bennetts <andrew.bennetts at canonical.com> writes:
[...]
> > I'm not sure we ever claimed that?
> 
> I quoted the wiki above in the thread:
> 
> http://bazaar-vcs.org/Welcome?action=recall&rev=120
> Revision 120 as of 2007-01-25 16:00:21
> 
> "We expect 1.0 to release by March 2007 with performance equivalent to
> the best in the field."

Ah, I see.  FWIW, I seem to recall that in many respects, we were pretty close.
Between dirstate and packs we did have a backend that was pretty similar in
performance characteristics to the “best in the field”, so the expectation
wasn't unfounded.

In hindsight that claim was unfortunate, though.

> You can add this one:
> 
> http://bazaar-vcs.org/Benchmarks/SpaceEfficiency
> "Comparing the average of the ratios above, Bazaar is 22% more
> efficient than Mercurial and 15% more efficient than Git."
> 
> This one is still there, has been so for quite some time. Now, look at
> how the benchmark was done (project without history to benchmark a
> tool whose _point_ is to manipulate history). Look at another
> independant benchmark like
> http://vcscompare.blogspot.com/2008/06/git-mercurial-bazaar-repository-size.html
> then take your conclusions.

I guess a contributing factor here was that in the effort to produce simple,
easily describable and reproducible benchmarks that they got over-simplified.
Certainly at the time of March 2007 it was pretty hard to use the same
real-world history in different tools for a fair comparison, so it was easier to
leave that part out.  Now that the fast-import format is somewhat ubiquitous
(and the tools to read it are increasingly reliable) it's easier to do better
here.  (Not that we weren't testing on real-world histories when developing, but
not in a way that was amenable to publishing as an apples-to-apples benchmark.)

That said, the numbers on that post do seem out of whack with what I'd expect...
but I'm fairly sure there was a thread about that months ago, and I'd rather not
have that discussion all over again!

-Andrew.





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