What else besides cache depends on article numbering at the nntp server?

What else besides cache depends on article numbering at the nntp server?

[SL Baur]

For those who tuned in late, my nntp server reset its article numbers
to 1 about two weeks ago.  Gnus has never recovered.

I've deleted all ~/News/cache directories, but M-x gnus still hangs at 
startup on a second nntp read (which I had never seen before this
whole episode started).

I have verified that Gnus Does The Right Thing with the specific
newsgroup entries that I can view with `G E' in the *Topics* buffer.
Marks outside of the article range retrieved from the server go away
when the cache for the group is removed.

I can also startup a fully functional Gnus with the sequence:

M-x gnus-no-server
C-u 5 g

So why doesn't `M-x gnus' work any more?

Re: What else besides cache depends on article numbering at the nntp server?

[SL Baur]

27,000 zombie groups where the group creation date has been advanced,
that's what. :-( :-( :-(

Deleting zombie groups is still as hideously slow now as it was 3
years ago (~7 _hours_ to delete 1000 out of 27,000 groups on a Pentium
200).  Sigh.

I'll die of old age before I get things back to where they were 2
weeks ago.