[PATCH] emacs: call "notmuch tag" only once when archiving a thread

[Tomi Ollila]

On Tue,  3 Jan 2012 20:29:06 +0200, Jani Nikula <jani at nikula.org> wrote:
> Optimize thread archiving by combining all the -inbox tagging operations to
> a single "notmuch tag" call. Also skip redisplay of tag changes in current
> buffer, as it is immediately killed by the archiving functions.
> 
> For threads in the order of tens or a hundred inbox tagged messages, this
> gives a noticeable speedup.
> 
> On the downside, IIRC Xapian does not perform very well if the query (in
> this case a lot of message-ids OR'd together) is very big. It is unknown to
> me at which point this approach would become slower than the original one
> by one tagging approach, if ever.
> 
> Also, this introduces a limitation to the number of messages that can be
> archived at the same time (through ARG_MAX limiting the command line). At
> least on Linux this seems more like a theoretical limitation than a real
> one.

IIRC some systems have like 32768 byte command line limit.
If the change did tagging in like 100-message batches then this limit is
hardly exceeded (if message-id's max 80 characters then command line is
8000+ bytes)...
Hmm -- is there a length limit for message-id. If not maybe when appending 
message id's keep counting length and tag in batches based on that lenght
value.

Hundreds of messages per tagging operation instead of one is good
improvements.

> Signed-off-by: Jani Nikula <jani at nikula.org>

Tomi