Help with few questions

[Egoitz Aurrekoetxea]

Good afternoon,

I would be very thankful if you could clarify me these questions. Have
not been able to find documentation for them and my testing env has not
been able too :) of clarifying me these doubts... Here I go :)

- Some friendly mate, has told me here that when you enable Xapian
engine in Cyrus 3.0 and have a master/slave replication, Squatter in
rolling mode should be enabled in both, the master and the slave. I
understand the master should be using it for indexing with Xapian the
new mail entering in mailboxes, mail movement... and in the slave for
applying the Xapian transactions being applied and sent from the master.
But, how can be that having the same line in events, depending in
whether it's master or slave does what just should do?. The sync_log: on
and sync_log_channels: squatter should be too enabled in both master or
slave?. Or just in one of them?. I haven't never run a Cyrus replication
of Xapian databases.. so this is new for me and don't understand how all
this param behave and if should be enabled in both master and slave. I
would like to use rolling Squatter in the master and that changes to be
sent to the slave. 

- search_fuzzy_always: 1 , causes all searches to go through Xapian
engine. Being so good as it seems (and the way it speeds in my testing
env search operations, it's nice!!), what could be the reason for not
having it enabled by default?. Can it have some kind of problem?. I
can't see them... Just for avoiding surprises.

- Bron, in this post
https://fastmail.blog/2014/12/01/email-search-system/ told that Fastmail
was not able to handle with just one Xapian default database (even on
SSD disks) all traffic. So he said Fastmail was using a in-memory
filesystem for a database (called temp) for new email. Later another for
cleaning up that in memory filesystem. And later one more, for keeping
definitively the content. You seemed to use a Squatter command for
moving elements between databases. Concretely (sudo -u cyrus
/usr/cyrus/bin/squatter -C /etc/cyrus/imapd-sloti30t01.conf -v -z
archive -t temp,meta,data,archive -u brong). I assume that compacts all
elements from all databases to archive?. If I wanted to compact elements
from temp to data, the command should be "sudo -u cyrus
/usr/cyrus/bin/squatter -C /etc/cyrus/imapd-sloti30t01.conf -v -z data
-t temp -u brong" (in this example for user brong) ??. I assume you
launch something like it with a cron weekly and it's done?. 

- If something went wrong when the upgrade proccess from 2.4 to 3.0,
could I setup 3.0 as master of the 2.4 and later make 2.4 master again?.
Could that cause info loosing?. I assume yes but just 
for knowing posibilities.

- When a Xapian or conversation index becomes broken, a reconstruct
could recover?. What could be the repairing procedure?. 

Thank you so much mates. Sorry for having so many questions... but
neither testing nor documentation or mailing lists have been able to
clarify me them. 

Best regards,

-- 

EGOITZ AURREKOETXEA 
Departamento de sistemas 
944 209 470
Parque Tecnológico. Edificio 103
48170 Zamudio (Bizkaia) 
egoitz at sarenet.es 
www.sarenet.es [1] 
Antes de imprimir este correo electrónico piense si es necesario
hacerlo. 

Links:
------
[1] http://www.sarenet.es
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.andrew.cmu.edu/pipermail/info-cyrus/attachments/20190108/9f1a47aa/attachment.html>