Weird path appearing in skiplist checkpointing?

[Karl Pielorz]

Hi,

We're currently running Cyrus IMAP 2.3.18 on FreeBSD 7.x amd64, on a 
machine with ECC and ZFS as the backing store (this machine has been in 
service for quite a while - through a number of IMAPd upgrades). No drive, 
memory or ZFS errors are logged.

Recently, a couple of users have noticed that when they visit seldom used 
folders, all the mail is marked as 'Unread' (when it wasn't before). 
Marking mail as read - then leaving the folder, or restarting the client - 
and it appears as 'Read' still - but at some random point, it all gets 
flipped back to 'Unread' (these are not 'shared-seen' folders).

Looking at the server - I found the following logged (the only thing I 
could see that was 'out of the ordinary'):

"
Feb 20 07:19:29 server imaps[52821]: skiplist: checkpointed 
/vol/server/imap/user/j/jason.seen (32 records, 36380 bytes) in 0 seconds
Feb 20 07:19:53 server imaps[52820]: skiplist: checkpointed 
/vol/server/imap/user/f/fred.seen (11 records, 18868 bytes) in 0 seconds
Feb 20 08:47:43 server imaps[54108]: skiplist: checkpointed 
/vol/server/imap/user/q/ÿÿÿÿÿÿÿÿreginald.seen (2 records, 324 
bytes) in 0 seconds
Feb 20 08:54:58 server imaps[75469]: skiplist: checkpointed 
/vol/server/imap/user/j/john.seen (13 records, 1124 bytes) in 0 seconds
"

I don't like the look of the entry for 'reginald' - on the actual file 
system we have:

/vol/server/imap/user/q/????????andrew.seen
/vol/server/imap/user/q/????????darren.seen
/vol/server/imap/user/q/????????john.seen
/vol/server/imap/user/q/????????reginald.seen

Which is odd, as well as the more expected:

/vol/server/imap/user/a/andrew.seen
/vol/server/imap/user/j/john.seen
/vol/server/imap/user/d/darren.seen
/vol/server/imap/user/r/reginald.seen

There's about 30 users on the system - but only the ones above have both 
.seen files under the regular, as well as 'q' directories. Two of the above 
users have noticed the symptom where folders suddenly 'ping' back to all 
messages unseen. I suspect the others either haven't noticed, or just 
thought it was them.

Any ideas?

Regards,

-Karl