(gnus-summary-goto-article <message-id>) extremely slow for certain IMAP server

[Tassilo Horn <tassilo@member.fsf.org>]

Hi all,

I maintain Org-mode's org-gnus.el, which allows linking to Gnus articles
in Org-mode.  Links to articles are stored by their group and their
message-id.  When following a link a call like

  (gnus-summary-goto-article <message-id>)

will be done.  Unfortunately, for Sébastien (in Cc) this call to a
message on some IMAP server takes ages for bigger groups (~5 minutes).

We've edebugged and profiled the gnus code, and the culprit is the
function `nnimap-request-article-part'.  When given a message-id instead
of an article number, that function will query the IMAP server with
`imap-search', and then emacs hangs 5 minutes till the server finally
responds.

Ok, it's basically the server's fault, but can't Gnus do any better?
Especially, the mapping message-id to article number is also contained
in the .overview file of the group, but it seems that this file is not
checked.

Or can this call to `imap-search' somehow be omitted by optional Gnus
features like the gnus registry?

You can check the full Org-mode thread with the report and all debugging
details at

  http://thread.gmane.org/gmane.emacs.orgmode/26722/focus=27590

Bye,
Tassilo