Empty conversations db after sync from 2.4 to 3.0

[Sebastian Hagedorn]

Hi,

in Github issue #2376 I have identified an issue with syncing from Cyrus 
2.4 to Cyrus 3.0 when using Xapian and conversations. After running 
sync_client -u for a user, the mail is replicated to the server running 
3.0.8, but the conversations db for that user only contains rudimentary 
information, e.g.:

% ctl_conversationsdb -v -d a102382
$COUNTED_FLAGS
Fuser.a102382	0 (572 0 0)

This can be fixed by dumping and rebuilding the conversations db like this:

% ctl_conversationsdb -z a102382
% ctl_conversationsdb -b a102382

Is that expected behavior? We can deal with it if it is, I would just like 
to understand if we're doing something wrong.
-- 
    .:.Sebastian Hagedorn - Weyertal 121 (Gebäude 133), Zimmer 2.02.:.
                 .:.Regionales Rechenzentrum (RRZK).:.
   .:.Universität zu Köln / Cologne University - ✆ +49-221-470-89578.:.