maildir, how to always add size tags to filename (,S=).

[Sergei Franco]

Hi There,

I have thoroughly read through documentation and wiki and I simply cannot
find how to force dovecot to always add the size tag to the filename when
using maildir format.

We are using dovecot 2.2.9 (whatever comes from ubuntu 14.04 LTS).
We are using dovecot in conjunction with exim with maidirsize file enabled
and maildir quotas.

For example exim has following configuration:

maildir_tag        = ,S=$message_size

Which adds the size to the filename of the message. This has enormous
(orders of magnitude) performance benefit as to calculate quota one does
not need to stat every single file (only getents for each directory).

I have wrote a script that adds the size tag retrospectively to files it
didn't had it, and rebuild the dovecot index/cache if changes where made.
This worked fine.

Behaviour of dovecot is very peculiar: it generally adds the ,S= tag (along
with ,W= tag) but occasionally it does not (I wander if it depends on the
IMAP client).

Is there anyway to force dovecot to add size tag to the files (like with
exim example above)?

Thank you very much.

Sergei.