How to detect out-of-sync condition

[Joseph Tam]

On Fri, 13 Mar 2015, Cliff Hayes writes:

>> By closing off other avenues other than dovecot imap/pop/lda/etc.,
>> the indices will stay sync'd.
>
> I use dovecot's lda and dovecot's sieve filter.

Then I'm not sure how mailboxes ever get out of sync.

> So it looks like I need to compare the index/mailbox mtimes as you suggest.
>
> What am I looking for?
> I see that the indexes are updated when I run the resync.
>
> I checked my mailbox (that was not resynced) and noticed that
> dovecot.index last update was 16 days ago.

Just to be clear, you're talking "doveadm index ...", yes?

You might have to check dovecot.index.log* as well as they could contain
the latest changes that have yet to propagate to the main index file.

 	http://wiki2.dovecot.org/Design/Indexes/TransactionLog

> So am I resyncing if the gap is over x days?
> If so, is there a way to resync just those mailboxes with a doveadm
> command or do I have to write a program look for that condition and run
> doveadm when matched?

It's possible that "doveadm index" checks modification times as an
optimization measure.  My recommended game plan:

 	1) Are your indices *really* out of date (checks logs as
 	Steffen recommends)?

 	2) If so, how do they get out of date and can you avoid it?

 	3) If you can't avoid it, does it cause real problems?  Most
 	of the time, dovecot will seemlessly rebuild it and
 	it's transparent to the user.

 	4) If you got this far, run a trial "doveadm index -A INBOX"
 	(assuming you're just concerned about INBOXs) to see if it's
 	really such a bad operation.  As Knuth (hallowed be thy
 	name!) said, "premature optimization is the root of all evil."

Only after all these steps are found to be unsatisfactory would I consider
writing your own scan and fix tool.

Joseph Tam <jtam.home at gmail.com>