is there a particular reason you need the db updated in real-time and "know the count of registered users and the source IP / user-agent / username data." ?
if it's for something outside of kamailio, id recommend using a module like evapi to push the data in real-time to an application that can consume it.
you can us routes like:

route[SAVE_LOCATION] {
    if (!save("location", "0x04")) {
        sl_reply_error();
        exit;
    }
    route(REGISTER_UPDATE_EVENT)
}

event_route[usrloc:contact-expired] {
    route(REGISTER_EXPIRE_EVENT);
}

route[REGISTER_UPDATE_EVENT] {
    if (reg_fetch_contacts("location", "$fu", "caller")) {
        $var(i) = 0;
        while ($var(i) < $(ulc(caller=>count))) {
            evapi_relay("{\"event\":\"register-update\",\n\"data\":{\"aor\":\"$(ulc(caller=>aor))\",\"addr\":\"$(ulc(caller=>addr)[$var(i)])\"\n}");
            $var(i) = $var(i) + 1;
        }
    }
}

route[REGISTER_EXPIRE_EVENT] {
    xlog("L_INFO", "registration [$ulc(exp=>aor)] expired");
    evapi_relay("{\"event\":\"register-expire\",\n\"data\":{\"aor\":\"$ulc(exp=>aor)}\n}");
}

On Thu, Jan 9, 2020 at 3:14 AM Voip support <voipexpert0@gmail.com> wrote:
Dear Community,

I am facing an issue with using the usrloc and registrar module to save registration informations in database.
It works for me but when tested yesterday with around 1500-1600 users i got a lot of queries on database mostly SELECT. I figured out that changing db_mode to 0 resolves the issue because it works totally in memory (almost no select query on DB).
So i think its location module.

I tried db_mode=3 and db_mode=2 but both create a lot of load on database.

The only function i need is to store some information of REGISTER in DB to know the count of registered users and the source IP / user-agent / username data.
It needs to be saved in table on successfull REGISTRATION and removed when registration is expired or somebody UN-REGISTER.

When used location module for that there was lots of queries like this (20000-50000 per second): 

select `contact`,`expires`,`q`,`callid`,`cseq`,`flags`,`cflags`,`user_agent`,`received`,`path`,`socket`,`methods`,`last_modified`,`ruid`,`instance`,`reg_id`,`server_id`,`connection_id`,`keepalive` from `location` where `username`='xxxx' order by q

update `location` set `expires`='2020-01-08 18:51:39',`q`=-1.000000 ,`cseq`=2042,`flags`=0,`cflags`=64,`user_agent`='n/a',`received`='sip:xxxx:5060',`path`=NULL,`socket`='udp:xxxx:20051',`methods`=NULL,`last_modified`='2020-01-08 18:50:39',`callid`='1205705227@xxxx',`instance`=NULL,`reg_id`=0,`server_id`=0,`connection_id`=-1,`keepalive`=1,`contact`='sip:1019@xxx:5060' where `ruid`='uloc-5e1642a3-2b90-0161'

Looking up for ideas how to resolve this issue.
I was thinking of implementing INSERT UPDATE and DELETE based on SQLops.
But how to recognize that REGISTER was expiered?

I would like location module to work mostly like in-memory.
For each new registration INSERT entry to DB, each REGISTER re-new an UPDATE or DELETE should be triggered.
 So i would expect for 1000 users around 2000 operations per minute.

Best regards,
Tom

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