Re: Maildir backend

[prj@po.cwru.edu (Paul Jarc)]

Jérôme Marant <jerome.marant@fr.thalesgroup.com> wrote:
>   I'm trying to understand why it is slow on startup.

I haven't profiled it, but I'm pretty sure it's because it read all
the NOV information at startup.  It uses this information to build a
fast mapping among filenames, article numbers, and Message-IDs, which
speeds things up later when we want to find a message by Message-ID,
for example.

Currently article numbers are only stored in memory, so they change
between Gnus sessions.  This messes with the cache, the agent, and
'seen marks, so I'm going to change it when I have some time.  As part
of that revision, I think I can get rid of the slow startup.  E.g., I
might create a new subdirectory in .nnmaildir/ which contains files
with names like this:
154:<20020313115128.A9018@fr.thalesgroup.com>:1016016979.15575.multivac.cwru.edu
I.e., article-number:message-id:unique-part-of-filename-in-cur.  Then
when we're looking for an article, we can just scan this directory,
looking for whichever identification field we happen to have.  Since
all the information here is contained in the filename, the files can
be empty, and can even be hard links to a single file to avoid
consuming lots of inodes.

>   Could you please explain how nnmaildir works, mainly the content of
>   .nnmaildir/marks? There is also a markfile file that seems to
>   be always empty. What is it for?

Have you read <URL:http://multivac.cwru.edu./nnmaildir/using/#marks>?

> NOV can be disable if nov-is-evil is non nil right?

Not for nnmaildir.  Supporting such an option means more code and more
work.  I think it's better to spend that effort on making the NOV code
work correctly, so no one cares about turning it off.


paul