dovecot - Mar 2011 - warnings from 2.0.11

During a stress test dovecot-2.0.11 logs many warnings:

Mar  8 06:19:52 gromit dovecot[59204]: imap(pid 68864 user user15): Warning:
/Volumes/Mail/user15/dovecot-uidlist: Duplicate file entry at line 183:
1299556557.M571530P31883.gromit.example.com,S=21175,W=21549 (uid 67 -> 250)
Mar  8 06:20:10 gromit dovecot[59204]: imap(pid 68865 user user34): Warning:
/Volumes/Mail/user34/dovecot-uidlist: Duplicate file entry at line 230:
1299535329.M679065P61136.gromit.example.com,S=11040,W=11247 (uid 17 -> 240)
Mar  8 06:20:10 gromit dovecot[59204]: imap(pid 68865 user user34): Warning:
/Volumes/Mail/user34/dovecot-uidlist: Duplicate file entry at line 240:
1299535329.M902424P61136.gromit.example.com,S=12843,W=13075 (uid 30 -> 250)
Mar  8 06:20:10 gromit dovecot[59204]: imap(pid 68865 user user34): Warning:
/Volumes/Mail/user34/dovecot-uidlist: Duplicate file entry at line 266:
1299547358.M587728P69303.gromit.example.com,S=13637,W=13772 (uid 108 -> 276)
Mar  8 06:20:10 gromit dovecot[59204]: imap(pid 68865 user user34): Warning:
/Volumes/Mail/user34/dovecot-uidlist: Duplicate file entry at line 275:
1299558462.M498819P35210.gromit.example.com,S=15495,W=15663 (uid 160 -> 285)
Mar  8 06:20:11 gromit dovecot[59204]: imap(pid 68864 user user36): Warning:
/Volumes/Mail/user36/dovecot-uidlist: Duplicate file entry at line 281:
1299535339.M353973P61136.gromit.example.com,S=4498,W=4581 (uid 360 -> 604)
Mar  8 06:21:00 gromit dovecot[59204]: imap(pid 68864 user user239): Warning:
/Volumes/Mail/user239/dovecot-uidlist: Duplicate file entry at line 105:
1299547390.M813768P69393.gromit.example.com,S=4773,W=4861 (uid 22 -> 164)
Mar  8 06:21:00 gromit dovecot[59204]: imap(pid 68864 user user239): Warning:
/Volumes/Mail/user239/dovecot-uidlist: Duplicate file entry at line 106:
1299570075.M267312P49194.gromit.example.com,S=8041,W=8181 (uid 115 -> 165)
Mar  8 06:28:24 gromit dovecot[59204]: imap(pid 69295 user user274): Warning:
/Volumes/Mail/user274/dovecot-uidlist: Duplicate file entry at line 2020:
1299548064.M880781P67832.gromit.example.com,S=4976,W=5076 (uid 247 -> 2500)
Mar  8 06:29:23 gromit dovecot[59204]: imap(pid 68973 user user115): Warning:
/Volumes/Mail/user115/dovecot-uidlist: Duplicate file entry at line 526:
1299537039.M676050P61136.gromit.example.com,S=2485,W=2534 (uid 8 -> 1082)
Mar  8 06:31:37 gromit dovecot[59204]: imap(pid 68971 user user114): Warning:
/Volumes/Mail/user114/dovecot-uidlist: Duplicate file entry at line 667:
1299564058.M124508P40871.gromit.example.com,S=1187940,W=1207707 (uid 229 ->
780) - retrying by re-reading from beginning
Mar  8 06:32:14 gromit dovecot[59204]: imap(pid 68971 user user114): Warning:
Maildir /Volumes/Mail/user114: Expunged message reappeared, giving a new UID
(old uid=229,
file=1299564058.M124508P40871.gromit.example.com,S=1187940,W=1207707:2,S)
Mar  8 06:39:22 gromit dovecot[59204]: imap(pid 68911 user user105): Warning:
Maildir /Volumes/Mail/user105: Synchronization took 155 seconds (0 new msgs, 0
flag change attempts, 585 expunge attempts)

Is there anything I need to reconfigure to prevent these?  Thanks.

On 8.3.2011, at 21.54, Mike Abbott wrote:
> During a stress test dovecot-2.0.11 logs many warnings:
> 
> Mar  8 06:19:52 gromit dovecot[59204]: imap(pid 68864 user user15):
Warning: /Volumes/Mail/user15/dovecot-uidlist: Duplicate file entry at line 183:
1299556557.M571530P31883.gromit.example.com,S=21175,W=21549 (uid 67 -> 250)
Didn't you get these with v1.x too before? I don't think the Maildir
code has changed much since v1.2.
> Is there anything I need to reconfigure to prevent these?  Thanks.
They just shouldn't be happening. Can you easily reproduce this by running
imaptest against a single user?

> Can you easily reproduce this by running imaptest against a single user?
Nope.  Any special imaptest arguments other than user=... pass=... host=...
mbox=...?  I ran it for a few hours with none of the warnings.

On 10.3.2011, at 2.43, Mike Abbott wrote:
>> Can you easily reproduce this by running imaptest against a single
user?
> 
> Nope.  Any special imaptest arguments other than user=... pass=... host=...
mbox=...?  I ran it for a few hours with none of the warnings.
Maybe it has to do with the number of mails in the mailbox? Did those users who
had the warnings have a lot of mails? imaptest normally keeps only about 30
mails, but that can be increased with:

msgs=10000 delete=10 expunge=10

> Maybe it has to do with the number of mails in the mailbox?
Clever thought, but while some of the users receiving the warnings have 30k
messages, others have only a few hundred.
> msgs=10000 delete=10 expunge=10
Five hours running, no warnings.  Any other thoughts?

On 10.3.2011, at 23.24, Mike Abbott wrote:
>> Maybe it has to do with the number of mails in the mailbox?
> 
> Clever thought, but while some of the users receiving the warnings have 30k
messages, others have only a few hundred.
What kind of a test are you doing that causes these warnings?