At 10:45 PM +0100 2/12/08, Rody imposed structure on a stream of electrons, yielding:
The opinions vary slightly when it comes to using mtime or ctime. I've chosen ctime because i believe using mtime will not garantee that there aren't any mails left which are actually older than 30 days. I believe there are cases where mtime may get changed, where ctime will not. Also, ctime starts counting from the moment the mail gets dropped in a certain mailbox.
Yes, but you may also care that ctime is reset when a client has Dovecot move a message from one subfolder to another within a Maildir. I'm not sure why Dovecot does it, but a look at the messages in the non-INBOX parts of my Maildir reveals that the ctime is always later than the mtime, and the contents (Received headers) makes it clear that Dovecot sets the mtime of messages to the original mtime (i.e. original delivery time) when copying them.
Hopefully Timo will speak up on this, but I have a vague recollection of him saying that Dovecot never modifies message contents as a matter of principle, and it seems to me that the design of Maildir assumes that the mailstore server follows that principle rigorously. That should make mtime quite static for an individual file, and it looks to me like Dovecot even makes an effort to preserve the delivery time of a message by replicating the mtime from the original file to the new one when copying a message between subfolders.
-- Bill Cole bill@scconsult.com