nnchoke-retrieve-groups and nnchoke-request-group

[Greg Stark <gsstark@MIT.EDU>]

In rewriting and using my backend i've realized that gnus sometimes uses
*-retrieve-groups to activate a bunch of groups and sometimes repeatedly calls
*-request-group. I think it should always use *-retrieve-groups. That way the
backend can choose to handle it however is most efficient. In my particular
case it's about five times faster and the user feedback is vastly superior
(since i can indicate how many groups remain to be handled) if Gnus uses
*-retrieve-groups. 


On a similar note, if i set gnus-read-active-file to 'some Gnus is smart
enough to only ask for some groups, but it seems to still ask for more than it
really needs to. It seems to ask for anything that isn't a zombie or killed
group, even though i have gnus-activate-level and
gnus-activate-foreign-newsgroups set much lower so it's asking for active file
information about group information it isn't even planning on using.


I think these problems are actually related. It doesn't really make sense to
have a gnus-read-active-file variable, there should maybe be a
nntp-read-active-file which helps decide which NNTP query to use to complete
the retrieve-groups request, but there's no reason for a user to change how
the interface between Gnus and the backends go about they're business. Well i
suppose the distinction between 'some and t is useful, but i don't think the
distinction between nil and 'some should be made by Gnus; i think that should
be decided by an nntp variable.


greg