dovecot - Jan 2013 - Fixing bad maildir message sizes

Hello.

As stated in my previous message, we have some old compressed maildir messages
with incorrect sizes in the filename.  These messages cause dovecot 2.x
problems.

I'm trying to write a script to crawl all our messages, check the actual
message size and if necessary, fix the filename.  However, when I do this,
dovecot gives the message a new UID on next login.  If I change the filename in
dovecot-uidlist, dovecot still gives a new UID on next login.  If I change
dovecot-uidlist and delete the index, then the UID is preserved.

Re-indexing our millions of mailboxes is not a great solution for us.  Is there
a good way to fix this?

On 21.1.2013, at 21.54, Richard Platel <rplatel at tucows.com> wrote:
> As stated in my previous message, we have some old compressed maildir
messages with incorrect sizes in the filename.  These messages cause dovecot 2.x
problems.
> 
> I'm trying to write a script to crawl all our messages, check the
actual message size and if necessary, fix the filename.  However, when I do
this, dovecot gives the message a new UID on next login.  If I change the
filename in dovecot-uidlist, dovecot still gives a new UID on next login.  If I
change dovecot-uidlist and delete the index, then the UID is preserved.
I don't really understand why deleting dovecot.index* would make a
difference here, except maybe as a workaround in case the user has that mailbox
selected, because the filenames could be cached in memory.

http://dovecot.org/tools/maildir-size-fix.pl
http://dovecot.org/tools/maildir-size-check.sh

Those scripts kind of do what you want, except not fully, so it would be nice to
get one fully finished one :) The best way for the script to would would be to:

 * scan through a maildir, figure out what needs to be renamed to what, but
don't actually do it
 * lock the maildir with dovecot-uidlist.lock (src/util/maildirlock comes with
dovecot)
 * doveadm kick user's imap/pop3 sessions, and even better if it was
possible to kill -9 any pending processes
 * rename the files and update dovecot-uidlist
 * delete dovecot-uidlist.lock

This separately for each folder.