Jim Blandy <email@example.com> writes:
> Well, union directories don't handle pulling together things from
> different servers.
I'm not sure this is a big problem, actually...
Currently, we have a theoretical idea of how cross-repository
references work: basically, that a "pointer" to a node would indicate
that that node lives at a different repository (and would mention the
information needed to retrieve it). Thus, any directory entry could
be a reference to a remote object.
The motivation for this is to be able to branch off repository X,
storing the branch in your own repository Y. You don't even need
write access to X.
Union directories don't add any difficulties that weren't already
there, as far as I can tell. You just store references to remote
nodes as in any other kind of directory.
Having commits be atomic across multiple repositories is probably
difficult to the point of impossibility, granted; but the feature is
still quite useful even if commits must be limited to a single
repository at a time. Anyway, this limitation is not unique to
distributed union directories -- it applies to any working copy whose
data comes from two different repositories, by whatever means.
> I wonder what kind of meaning one can assign to transactions if one
> has a working copy assembled from multiple servers. Are transactions
> meaningful across multiple independent servers?
Received on Sat Oct 21 14:36:16 2006