bzr-git, the git map, fetching revisions, and being very slow

[Jelmer Vernooij]

On Sun, 2009-11-22 at 09:19 +0900, Stephen J. Turnbull wrote: 
> Jelmer Vernooij writes:
> 
>  > It's unfair to compare imports from git to bazaar with native clones
>  > between git repositories. Compare with pulling from a git repository to
>  > a git repository using bzr instead.
> 
> Of course it's not unfair, because the comparison we should care about
> is performance in the user's eyes. The user may be willing to make
> the tradeoff, but the more we say about why they should in the face of
> obvious defects less they'll trust us.  Note that that's different
> from *explaining* the performance differential, such as "This
> operation is sufficiently rare that we put low priority on optimizing
> it, and it's a relatively difficult task since we are Bazaar experts,
> not git experts.  You should not extrapolate and assume all bzr-git
> interactions will have such low performance."
My point was that copying data from one repository in a particular
format into another repository in the same format is *always* going to
be faster than copying into a different format because there would be
some sort of conversion involved in the second case. It is never going
to be as fast.

Perhaps we should be telling the user that an operation is expected to
be slower when fetching between differing formats. 

Cheers,

Jelmer