[Dovecot] imapc with Outlook.com transfers max 22-23 messages per mailbox!?

[Nicholas Riley]

Hi,

I'm trying to migrate a user from Outlook.com IMAP to Dovecot.  I'm 
using a setup similar to that on 
http://wiki2.dovecot.org/Migration/Dsync:

imapc_host = imap-mail.outlook.com
imapc_user = [...]@hotmail.com
imapc_password = [...]
imapc_features = rfc822.size fetch-headers
mail_prefetch_count = 20

imapc_port = 993
imapc_ssl = imaps
imapc_ssl_verify = yes
ssl_client_ca_dir = /etc/ssl # this needs fixing on the wiki page 

Here's how I sync a single mailbox, which should have a few hundred 
messages in it:

% doveadm -D -v -c [...] sync -1 -R -u [...] -m Avalon imapc:

Output is at http://sabi.net/temp/sync.txt

But every mailbox contains at most 22-23 messages.

% for i in Maildir/**/cur; do
echo $i $(ls -1 $i | wc -l)
done
Maildir/Alaska/cur 23
Maildir/Avalon/cur 22
Maildir/Christine Scott/cur 22
Maildir/Cornell/cur 22
Maildir/Coupons/cur 10
Maildir/Deleted/cur 22
[...]

I was using 2.2.9 but I also tried with the dovecot-2.2 hg tip and did 
not see any difference.

Is there a rawlog equivalent for imapc?  I'm hoping that there is a 
simple protocol usage change that could let me get entire mailboxes.
-- 
Nicholas Riley <njriley at illinois.edu>