[notmuch] asynch operations protocol

[Jed Brown]

On Fri, 15 Jan 2010 09:59:54 -0400, David Bremner <bremner at unb.ca> wrote:
> Is this over/under engineered?  I spent roughly as long on the design as
> it took me to type :). Maybe the whole session id thing is redundant and
> could be done at the socket level. Or, getting more serious about the
> whole thing, maybe each queue operation should return an identifier.

The asynchronous interface I work with most is MPI.  There you get a
Request object when the operation is initiated and you can
{test,block}{one,some,any,all}, where the latter takes a list of
requests.  These variants are all useful, but of course they could be
implemented as needed.  I don't think that being able to support these
variants places any particular burden on the design.

I believe in performing operations with appropriate granularity, so I
wouldn't expect cases where you need to manage thousands of active
requests, thus I'm not sure the "session" grouping offers any real
benefit.  In any case, I'm not in favor of a single global flush.

Jed