Spam processing slows down group exit (was: Profiling)

[Reiner Steib <4.uce.03.r.s@nurfuerspam.de>]

On Tue, Dec 30 2003, Lars Magne Ingebrigtsen wrote:

> Gnus was feeling a bit more sluggish than usual, so I've spent a
> couple of hours profiling and fixing obvious things.

I noticed that leaving large nntp or nnml groups became kinda slow (I
didn't profile it, though).

I found that the group and topic parameters (spam/ham) are
calculated[1] for *every article* rather than once for each group
exit.  I have set up spam processing for some IMAP groups and all
Gmane groups[2], but not for nnml (and other nntp groups).

I added the following debug statements in `spam-group-ham-mark-p'...

  (gnus-message 9 "DEBUG: spam-group-ham-mark-p %s %s %s" group mark spam)

... and got the following output after leaving a group with 10
articles (entered with `10 RET'):

,----
| Exiting summary buffer and applying spam rules
| DEBUG: spam-group-ham-mark-p nnml+foo:bar 69 t [9 times]
| DEBUG: spam-group-ham-mark-p nnml+foo:bar 33 t
| DEBUG: spam-group-ham-mark-p nnml+foo:bar 69 nil [9 times]
| DEBUG: spam-group-ham-mark-p nnml+foo:bar 33 nil
| Marking spam as expired without moving it
`----

The function seems to be called from `spam-ham-copy-or-move-routine':

    (dolist (article articles)
      (when (spam-group-ham-mark-p gnus-newsgroup-name
				   (gnus-summary-article-mark article))
	(push article todo)))

Couldn't each possible mark be checked _once_ per group exit instead
once for every article?  (==> O(1) instead of O(n), AFAIKS.)

Why is `spam-ham-copy-or-move-routine' called in the first place?  I
have not requested any spam processing in this group.

Bye, Reiner.

[1] Using C-g after toggle-debug-on-quit, I saw that Gnus was doing
    this most of the time.

[2] See also <news:v94qw3y46d.fsf@marauder.physik.uni-ulm.de>:

   ("nnimap:spam\\.detected"
    (gnus-article-sort-functions '(gnus-article-sort-by-chars))
    (ham-process-destination "nnimap:INBOX" "nnimap:training.ham")
    (spam-contents gnus-group-spam-classification-spam))
   ("nnimap:\\(INBOX\\|other-folders\\)"
    (spam-process-destination . "nnimap:training.spam")
    (spam-contents gnus-group-spam-classification-ham))

   ("^gmane\\."
    (spam-process (gnus-group-spam-exit-processor-report-gmane)))
-- 
       ,,,
      (o o)
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