Second draft of logging patches

[David Bremner]

On Sat, 13 Nov 2010 06:25:57 +0100, Michal Sojka <sojkam1 at fel.cvut.cz> wrote:
> On Wed, 10 Nov 2010, David Bremner wrote:
> > I had a thought of a possibly interesting application of the (yet to be
> > written) log playback code. It could be use to implement a simple
> > queuing system where commands are only logged but not actually run on
> > the database. 

> Hi, I think this could be very interesting and that it could make the
> tagging operation asynchronous and thus faster as was suggested by
> Sebastian in id:"87k4l5whwe.fsf at SSpaeth.de".
> 
> In this case, however, the queuing should happen in the client, not in
> the library.

Agreed. The current implementation of automagically logging things in
the library would be undesirable here. That specific thing shouldn't be
too hard to change. Also worth thinking about is (optionally) using the
Maildir to log most tag changes; Maildirs are designed (imperfectly, but
still) to support simulataneous writes.  The database could then catch
up by reading the Maildir.

d