[Gnu-arch-users] Re: arch commit on large trees ?

[Matthieu Moy]

"Philippe Moutarlier" <address@hidden> writes:

> baz inventory -s | wc -l
>
> 22133 files

With that size of project, you should split your project into several
smaller ones, and use, for example, configurations (see baz
build-config) to manage the nested projects.

I'm not 100% happy with the way configuration work, but it's probably
the best way to scale up with arch.

> There are 2 delays : the first one is before even looking for the
> revision. Why ?

I don't know the exact algorithm, but this may be due to baz doing an
inventory of your local tree. Roughly, it does a "find + regexp
matching" in all the files of your tree. It happens to be quite slow
on large trees.

> Can we turn off the integrity check ? In general we have to trust our
> own file system ... (and back it up !) otherwise little could be done.
> In case of a purely local branch, I don't see the benefit of this
> check.

You will see it if you happen to get a corrupt revision library once
in your life. Arch just checks that you didn't modify the files in the
revision library. It's checking the chair-keyboard interface as much
as the filesystem or anything else actually.

Since the changeset uploaded in the archive is based on the content of
the revision library, it means that if you have a silently corrupted
revlib at revision N, all the content of your archive after revision N
is potentially unusable.

> I am a little disappointed that it seems  arch doesn't quite scale up to
> that project size.

By curiosity, which other RCS did you try, and what performance did
you get?

> That was what I heard around but I wanted to give a try for myself.
> I am afraid there is no way I could get my guys to buy it, which is
> too bad.

GNU Arch does have problems with really large trees (on the other
hand, it's extremely bandwidth-saving and puts very little load on the
server, so you can host a big number or medium projects on a
reasonable server). Bazaar 1.x improves some of the points, and you
may want to have a look at the future Bazaar 2.0, AKA Bazaar-NG, who
will have dramatically improved performances (but you'll have to wait
a few months before being able to use it for production).

-- 
Matthieu