[SR-Users] mariadb and sql_query_async: the db driver module doesn't support async query

[Daniel Tryba]

So trying to push some inserts/updates to the background I added:
async_workers=1
and
replaced

sql_xquery("ca", "$var(query)", "ra");
sql_result_free("ra");

with 

sql_query_async("ca", "$var(query)");

where: $var(query)="insert into CDR.callogs (accountcode,number) values
('"+$var(accountcode)+"',substring('"+$rU+"',1,4))";

Only to find out that the queries aren't inserted and the log contains:
/usr/sbin/kamailio[24754]: ERROR: sqlops [sql_api.c:429]:
sql_do_query_async(): the db driver module doesn't support async query

The table is an InnoDB some insert delayed should give these kind of
errors, but isn't the point of sql_query_async that it does the plain
normal insert in a background task?

Test machine: kamailio 4.2.5