[SR-Users] usrloc db_mode 2 and dropped contacts

[Alex Balashov]

Hi,

On 4.4.7, since switching to db_mode 2 for usrloc with the following settings:

   modparam("usrloc", "db_mode", 2)
   modparam("usrloc", "timer_procs", 2)
   modparam("usrloc", "skip_remote_socket", 1)
   modparam("usrloc", "timer_interval", 30)
   modparam("usrloc", "matching_mode", 0)

I seem to run into a situation where, despite starting from zero local
registrations and an empty DB `location` table, out of ~1700
registrations visible in the runtime usrloc table, about 60-80 never
make it into the database.

This is because they're being continuously UPDATE'd rather than
INSERT'd, so there is some presumption that they should already be in
the Postgres database. But they're not.

This gap seems to very slowly grow over time. 

I understand that this option is intended to deal with a scenario like
that:

   https://kamailio.org/docs/modules/5.3.x/modules/usrloc.html#usrloc.p.db_check_update

but the documentation doesn't say it needs to be on for db_mode 2 to
work correctly, and it's off by default.

I'm wondering what causes certain registrants to get into this state in
the first place, where the registrar presumes that they've already been
synced to the DB and only need to be update'd on renewal, where in fact
they have not been synced.

Causes I've ruled out:

1) The contacts being ignored due to non-local socket or other
invalidation;

2) Contacts being explicitly deleted by an outside process.

Any ideas appreciated!

-- Alex

-- 
Alex Balashov | Principal | Evariste Systems LLC

Tel: +1-706-510-6800 / +1-800-250-5920 (toll-free)
Web: http://www.evaristesys.com/, http://www.csrpswitch.com/