The back end nnmairix enables you to call mairix
from within Gnus, either to query mairix with a search term or to
update the database. While visiting a message in the summary
buffer, you can use several pre-defined shortcuts for calling
mairix, e.g. to quickly search for all mails from the sender of
the current message or to display the whole thread associated
with the message, even if the mails are in different folders.
Additionally, you can create permanent nnmairix
groups which are bound to certain mairix searches. This way, you
can easily create a group containing mails from a certain sender,
with a certain subject line or even for one specific thread based
on the Message-ID. If you check for new mail in these folders
(e.g. by pressing g or M-g), they
automatically update themselves by calling mairix.
You might ask why you need nnmairix at all, since
mairix already creates the group, populates it with links to the
mails so that you can then access it with Gnus, right? Well, this
might work, but often does not—at least not
without problems. Most probably you will get strange article
counts, and sometimes you might see mails which Gnus claims have
already been canceled and are inaccessible. This is due to the
fact that Gnus isn't really amused when things are happening
behind its back. Another problem can be the mail back end itself,
e.g. if you use mairix with an IMAP server (I
had Dovecot complaining about corrupt index files when mairix
changed the contents of the search group). Using
nnmairix should circumvent these problems.
nnmairix is not really a mail back end—it's
actually more like a wrapper, sitting between a
“real” mail back end where mairix stores the searches
and the Gnus front end. You can choose between three different
mail back ends for the mairix folders: nnml,
nnmaildir or nnimap.
nnmairix will call the mairix binary so that the
search results are stored in folders named
zz_mairix-<NAME>-<NUMBER> on this mail
back end, but it will present these folders in the Gnus front end
only with <NAME>. You can use an existing mail
back end where you already store your mail, but if you're
uncomfortable with nnmairix creating new mail groups
alongside your other mail, you can also create e.g. a new
nnmaildir or nnml server exclusively
for mairix, but then make sure those servers do not accidentally
receive your new mail (see nnmairix caveats). A
special case exists if you want to use mairix remotely on an IMAP
server with nnimap—here the mairix folders and
your other mail must be on the same nnimap back
end.