How nndir works

[Harry Putnam <reader@newsguy.com>]

I'm using a little scripting to grab namazu output and generate
symlinks to the filenames it generates in a certain directory.

Also puts the namzu summaries into a numbered file and inserts URL to
each symlink created so that one browsing the summary file can use
those links to jump to the full message when needed.

I access this directory from gnus using nndir.
The directory name stays the same but on my next namazu search,
different messages are symlinked in there.  So far so good.

I just alt-g the nndir group and see the new messages.

Here's the rub:  My scripting creates numbered symlinks by checking
the directory and getting the highest numbered message adding 1 then
increment for each new link.  The summary message mentioned above is
just thrown into the directory with next highest number too.

Sometimes that summary message will end up with the same number it had
the previous time.  When that happens gnus shows me the old message.
(Which is actually deleted at that point).

Even if I CTRL - k the nndir group and recreate it with `G d'.  then
run alt-g, the newly inserted messages are there but if the summary
message happens to be the same number.... it still will have the
content of the previous (now deleted message).

Looking back at what I wrote it looks really confusing... let me
summarize again for clarity.

1) I create a directory populated with symlinks pointing to the files
   namazu has found hits in.
   View it from gnus with nndir.

2) I delete the directory and symlinks with rm -rf dir

3) Recreate directory and different symlinks behind gnus back with a
   new namazu search

In the created directory there is always a message with the ame
headers inserted that contains namazu output, line for line, along
with an URL to what ever symlink each section is about.

The symlinks are arrows to the files namazu has searched and found a
hit in.  They might change with each search.

Now if it happens that the message containing namazu summury ends up
with the same filename it had in previous search.   Gnus shows me the
previous file it seems.  Gnus must have kept it in memory or
something.

So my question is how to make gnus clear its memory or meta data so
that it displays the newest version of the namazu summary message.