Re: [Monotone-devel] [RFC] Monotone NETSYNC Hook Extension & Abstraction Layer

[Ralf S. Engelschall]

On Sun, Sep 23, 2007, Nathaniel Smith wrote:

> [...]
> > My partner Thomas Lotterer and I came up with the idea to solve the
> > problem at the server-side of the master repository by directly
> > enforcing the access control on keys, revisions, and certs during
> > NETSYNC and even _ROLLING BACK_ the _WHOLE_ NETSYNC transaction in
> > case an ACL fails. And I've now also developed an experimental
> > implementation for this and I have written a little bit more about this
> > stuff in my BLOG a few days ago (see the following URL for details:
> > http://trainofthoughts.org/blog/2007/09/16/distributed-vcs-central-acl/).
> > We are currently testing this stuff in practice with a few test
> > repositories. Looks promising so far.
>
> You're going to have a problem with the transaction handling here --
> the server does not and can not wrap a client connection into a single
> transaction.  The problem is that the server is multiplexing across
> multiple connections at once, but with sqlite (and RDBMSes generally,
> to some extent) there is no way to have multiple parallel transactions
> open at the same time, to keep separate the data that's arriving in
> parallel from multiple clients.  So the server commits regularly.

Hmmm... interesting point. Thanks for the hint. You're right, the
concurrent incoming connections could make real trouble here. I've to
investigate to see whether a workaround is possible or whether we really
hit against the wall here. Many thanks for clarifying this point.

                                       Ralf S. Engelschall
                                       address@hidden
                                       www.engelschall.com