Re: Question about atomic commits and "tree locking".

On Mon, Jun 16, 2008 at 11:33:47AM -0400, David Weintraub wrote:
> Most VCS with atomic commits (such as Perforce) don't allows multiple
> sets to commit at the same time. They're lined up one after another to
> make sure they don't interfere with each other. It's about the only
> single threaded activity that takes place in many systems.

The reason Perforce does it this way may be related to the
fact that it uses RCS internally. Modifying RCS files in parallel
is probably quite hard to get right.

Subversion OTOH uses a transactional filesystem, i.e. it supports
transactions much like a database does. It's much easier to implement
parallel commits if the data model used by the repository supports
multiple transactions out of the box.

Stefan