Second draft of logging patches

[David Bremner]

On Sun, 24 Oct 2010 18:01:02 -0300, david at tethera.net wrote:
> Here is my second try at logging, taking into account the feedback I
> got from Rob and Michal.  There is definitely some tidying to do; in
> particular I know the protoypes in public headers need
> documentation. Also, I should add a configuration option to
> enable configuration by command or something like that.

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. I'm not sure about the performance implications, but it
could be interesting because it eliminates the need to have a server
running in order to eliminate write contention for the tag database.
The "queue runner" could be as simple as a cron job, or it could be
something spawned by one of the queue operations; the point would be
that queueing could continue while the snapshot of the queue was run.

d