mail groups--re-count messages?

[John Palmieri <palmieri@math.mit.edu>]

First, here's my configuration:
   Gnus v5.4.11; nntp 5.0; nndoc 1.0; nnbabyl 1.0; nnfolder 1.0
   GNU Emacs 19.34.1 (sparc-sun-sunos4.1.3, X toolkit)

I use gnus to read my mail, with the nnbabyl backend.  After doing
this for several months, I have mail groups which gnus thinks have
hundreds of messages, but which have very few unexpired messages.
This situation (I think) makes certain operations slow, and I'm
wondering how to tell gnus how many messages there are in each group.

For example, I have the following as part of my nnmail-split-methods:
        ("mail.gnus" "ding-request\\|ding-announce")
While I cherish just about all of the messages from these lists, I
occasionally expire one or two of them.  Now, suppose I want a list of
all the messages in that mail group.  I select the group, and I am
told that there are 787 messages; how many do I want to get?  I hit
RET to ask for all of them, and (since many of them have expired) I
end up with a summary buffer showing 58 articles.  The problem is,
there is quite a noticeable delay while it loads those 58 articles
(saying things like "nnbabyl: Receiving headers (53%)").  

How can I speed this up?

-- 
John H. Palmieri
Department of Mathematics, M.I.T.
palmieri@math.mit.edu