[Dovecot] mysteriously disappearing RECENT flag

[Vadim Zeitlin]

On Mon, 22 Jan 2007 18:55:33 +0200 Timo Sirainen <tss at iki.fi> wrote:

 Thanks for the fast reply Timo!

TS> On Mon, 2007-01-22 at 17:38 +0100, Vadim Zeitlin wrote:
TS> > * STATUS "test" (MESSAGES 41 RECENT 0 UNSEEN 0)
TS> > 2 OK Status completed.
TS> > [--- switch to another window and copy a message to the test folder ---]
TS> 
TS> Copied using what program? Did it add X-UID or Status header?

 Copied using my own MUA (Mahogany) which uses c-client library and is
connected to the same (Dovecot) IMAP server, so the message is appended by
Dovecot itself. It does have X-UID and "Status: R" headers but I thought
they were appended by Dovecot itself, aren't they?

TS> > 3 status test (messages recent unseen)
TS> > * STATUS "test" (MESSAGES 42 RECENT 1 UNSEEN 0)
TS> > 3 OK Status completed.
TS> 
TS> If you do it again, does it still show RECENT 1?

 Yes. I did find a mention of an old (2003) bug which resulted in recent
flag being unset after status command but it was apparently fixed a long
time ago and, anyhow, status works just fine -- the problem only arises
when the folder is opened.

TS> >  Why does Dovecot send "0 RECENT" when the mailbox is opened when it had
TS> > just told that there was a recent message in it? And why is the message
TS> > effectively old (no \Recent in the FETCH reply)? Notice that if I look at
TS> > the MBOX file I see "Status: R" until command number 7, it becomes "Status:
TS> > RO" only when I log out -- but internally Dovecot clearly considers it to
TS> > be old long before that.
TS> 
TS> That is because it's using "lazy writes". You could try if setting
TS> mbox_lazy_writes=no changes anything.

 Well, yes, it does! This fixed the problem. I can live with this option
being turned on, of course, but I'm still curious as to why it helped. It
looks like some information is not being updated correctly somewhere if the
file is not rewritten on disk immediately.

 Anyhow, thanks for the hint about mbox_lazy_writes and I'd be glad to help
you to debug the problem further if you're interested. Please let me know
if you have any ideas about what would you like me to try (I can provide
the full log of the IMAP session which copies the message too if this could
be useful).

 Thanks,
VZ