Re: why does message-generate-headers take so long?

[Elias Oltmanns <oltmanns@uni-bonn.de>]

Ted Stern <dodecatheon@gmail.com> wrote:
> Hi all,
>
> Sending a message from CVS Emacs + CVS Gnus on Red Hat Enterprise
> Linux Workstation 4 (x86_64) takes quite a bit of time, so I profiled
> all message-* functions to see where the time hog was.
[...]
> Clearly, the most time is being spent in message-generate-headers, and
> the other long times are accumulated with it.  There are a lot of
> (while (re-search-forward)) loops, but this message was just a few
> lines long!

The search functions in cvs emacs that eventually call search_buffer
are really slow if the search string contains an i. This is because
the dotless i is now considered equivalent to the dotted i in
case-insensitive searches. This dotless i is a unicode character which
prevents search_buffer from using the fast boyer moore algorithm (if I
remember the name correctly).

I've raised this issue on emacs-devel quite some time ago but
apparently nobody cared to fix it since. Please see
<http://permalink.gmane.org/gmane.emacs.devel/53901>
for further information.

My temporary workaround is the following snippet in ~/.emacs:

--8<---------------cut here---------------start------------->8---
(unless (< emacs-major-version 22)
  (set-case-syntax 331856 "w" (standard-case-table))
  (set-case-syntax 331857 "w" (standard-case-table)))
--8<---------------cut here---------------end--------------->8---

Hope that helps.

Elias