I found a confusing thing. I simplified the configuration file ``` debug=3
/* set paths to location of modules */ mpath="/usr/local/kamailio/lib64/kamailio/modules/"
loadmodule "db_mysql.so" loadmodule "tm.so" loadmodule "sl.so"
loadmodule "presence.so" loadmodule "presence_xml.so"
modparam("presence_xml", "db_url", "mysql://kamailio:kamailiorw@localhost/kamailio52")
request_route { exit; } ``` #### Log Messages About db_url ``` 0(4147) DEBUG: <core> [core/modparam.c:83]: set_mod_param_regex(): 'presence_xml' matches module 'presence_xml' 0(4147) DEBUG: <core> [core/sr_module.c:711]: find_param_export(): found <db_url> in module presence_xml [/usr/local/kamailio/lib64/kamailio/modules/presence_xml.so] 0(4147) DEBUG: <core> [core/modparam.c:99]: set_mod_param_regex(): found <db_url> in module presence_xml [/usr/local/kamailio/lib64/kamailio/modules/presence_xml.so] ... 0(4149) DEBUG: <core> [core/sr_module.c:896]: init_mod(): presence 0(4149) DEBUG: presence [presence.c:282]: mod_init(): db_url=mysql://kamailio:kamailiorw@localhost/kamailio52/48/0x106853338 ... 0(4149) DEBUG: <core> [core/sr_module.c:896]: init_mod(): presence_xml 0(4149) DEBUG: presence_xml [presence_xml.c:159]: mod_init(): db_url=mysql://kamailio:kamailiorw@localhost/kamailio/46/0x1079a7d64 ... 0(4149) DEBUG: db_mysql [km_my_con.c:108]: db_mysql_new_connection(): opening connection: mysql://xxxx:xxxx@localhost/kamailio 0(4149) ERROR: db_mysql [km_my_con.c:139]: db_mysql_new_connection(): driver error: Unknown database 'kamailio' 0(4149) ERROR: <core> [db.c:319]: db_do_init2(): could not add connection to the pool 0(4149) ERROR: presence_xml [presence_xml.c:214]: mod_init(): while connecting to database 0(4149) ERROR: <core> [core/sr_module.c:899]: init_mod(): Error while initializing module presence_xml (/usr/local/kamailio/lib64/kamailio/modules/presence_xml.so) ERROR: error while initializing modules ``` I set presence_xml db_url only. But why presence db_url be set? And presence_xml db_url still is the default value.