[Dovecot] Many messages clustered around the same date.saved value

[Timo Sirainen]

On Sun, 2012-03-25 at 00:46 -0700, Joseph Tam wrote:
> Subject: Different user messages clustered around the same date.saved value
> 
> After updating dovecot to 2.1.3, I can now use "doveadm expunge -A ..."
> to iterate through all user trash folders and expunge old messages.
> 
> However, I noticed a strange thing: querying what would have been deleted
> 
>  	doveadm -ftab fetch -A "date.saved" mailbox Trash savedbefore 7d
> 
> showed many date.saved values are clustered around the same
> timestamp, even among different user's Trash mailbox.  One user's trash
> mailbox having the same date.saved is explained by a user deleting a
> lot of message at one time, but I can't explain why many different users
> would have messages with the same (or closeby) date.saved value.

Which mailbox format? With Maildir the date.saved is taken from
dovecot.index.cache file, and in some cases that might get dropped. If
it does, then it fallbacks to using the file's ctime.