Re: Improving Gnus speed

[Dan Christensen <jdc@uwo.ca>]

Lars Magne Ingebrigtsen <larsi@gnus.org> writes:

> Dan Christensen <jdc@uwo.ca> writes:
>
>> The upshot is that about 1.3s is date conversion for each article, the
>> rest has to do with the latest-date traversal and the actual sorting.
>
> Ah, right.  Thanks for benchmarking this.
>
> Perhaps the date parsing stuff should be pushed down into the C layer?
> Surely one of the many libraries already included in a standard Emacs
> build has a date parser already included...

Could be.  The lisp parser that we fall back onto in the worst case
is very complicated, handling all sorts of weird date formats.  But
it seems to me that it should be possible to quickly parse the most
common formats, and use slower code only when completely necessary.
Could it be that 99% of current e-mail/news has only a small number
of possible date formats?

Another idea for some backends is to rewrite the Date: header as an
X-Gnus-Date:  header when the article arrives.  We take the time to
carefully parse it on arrival, storing the result, and then avoid
re-doing the slow parsing every time we want to show the article.
This could work for backends like nnfolder, nnml, etc, in which Gnus
can easily edit the article.

But this is probably not worth it.  Better to just make date parsing
lightning fast if possible.

Dan