Kamailio delayed reponse in case of database load - sr-users

10 Dec 2019

Hello,

I have Kamailio installed as SIP redirect for an SBC to make routing decisions.

I'm using SQLOps module with postgresql 11.5 where I have multiple tables containing
each around 6M record of routing codes:
Code       options
392342  sup1|sup2|sup3
Where code field is of prefix_range data type and has a gist index.

I'm sending traffic of 300 CPS to SBC which is forwarding it to Kamailio, and Kamailio
respond with 300 multiple choice with the routing decision.

In normal cases, everything is going smoothly where Kamailio repsonds up to 50 ms.

But during the process of loading data to the routing tables, Kamailio response to SBC is
dramatically delayed , where for some calls it takes up to 7 seconds to respond.

Noting that during this process the data are loaded to staging tables and not to live
tables used by Kamailio.

Kamailio is installed on a VM with 32GB RAM and 16 vcores.

Following configuration is used in Kamailio:
fork=yes
children=10

following are the customized parameters in postgresql.conf
max_connections = 100
shared_buffers = 8GB
effective_cache_size = 24GB
maintenance_work_mem = 2GB
checkpoint_completion_target = 0.7
wal_buffers = 16MB
default_statistics_target = 100
random_page_cost = 1.1
effective_io_concurrency = 200
work_mem = 5242kB
min_wal_size = 1GB
max_wal_size = 2GB
max_worker_processes = 16
max_parallel_workers_per_gather = 8
max_parallel_workers = 16

Following is the routing logic I'm using:

route{

if (is_method("INVITE"))              {
$var(inc) = $(ct{param.value,tgrp});
xlog("L_INFO","CONTACT : $var(inc)" );
xlog("L_INFO","from number : $rU" );
if($var(inc)!=0)
route(customer);
route(block);

}
}

route[customer]
{
sql_query("cb", "select caid from customeridentification where 
trunk='$var(inc)'", "ra");
$var(cid)=$dbr(ra=>[0,0]);
sql_result_free("ra");
xlog("L_INFO","cid: $var(cid) \n");

sql_query("cb", "select routetablename from carrieraccount where 
caid=$var(cid)", "ra");
$var(tid)=$dbr(ra=>[0,0]);
sql_result_free("ra");

if($var(cid)!=0)
route(query);
else
route(block);

}

route[query]
{

#sql_query("cb", "select supplierid from route_$var(cid) where  prefix
@>'$rU' order by prefix limit 1", "ra");
sql_query("cb", "select
get_routing('$var(tid)','$rU')", "ra");
$var(sup)=$dbr(ra=>[0,0]);
sql_result_free("ra");
xlog("L_INFO","supplieris: $var(sup) \n");
#$var(x)=$(var(sup){s.replace,|,}{s.len})/4;

$var(a)=$(var(sup){s.len});
$var(z)=$(var(sup){s.replace,|,});
$var(b)=$(var(z){s.len});
$var(suplen)=$var(a) - $var(b);

if($var(sup)!=0)
route(send);
else
route(block);
}
route[send]
{
xlog("L_INFO","Inside Send \n");
$var(i)=0;
append_to_reply("Contact:");
while($var(i)<$var(suplen) + 1)
{
$var(s)=$(var(sup){s.select,$var(i),|});
$var(s)=$(var(s){s.select,0,;});
append_to_reply("<sip:$rU;tgrp=$(var(s){s.ltrim})@
xxx.xxx.xxx.xxx:5060;user=phone>");
if($var(i)<$var(suplen)) append_to_reply(",");
$var(i)=$var(i)+1;
}
append_to_reply("\r\n");
sl_send_reply("300","Multiple Choices");
exit;
}

route[block]
{
xlog("L_INFO","INSIDE BLOCK" );
append_to_reply("Contact:<sip:$rU;tgrp=999999@xxx.xxx.xxx.xxx:5060;user=phone>\r\n");
sl_send_reply("300","Multiple Choices");
exit;
}

How can we enhance the Kamailio response in case of load on the postgresql server.

Regards,
Ali Taher