Hello,
the current async query API requires that the connection is established, because it uses the database handle pointer as one of the parameter. That means the process initiating sql_query_async() attempts to connect if the connection is not on, and can get stuck for a while if the database server is not available. Probably can be refactored to do connect in the async task worker, but it's a change that has to be propagated to other modules like db_mysql, db_postgres and any other module using the async query db api function. Not expecting to be complex coding, but requiring time to do it.
While I added the async query db api function, it was at the time when Kamailio would fail to run if connection could not be initialized at the start up. Later someone else added sqlops connect_mode, so the connect is delayed, no longer done at the start up if its value is 1, but it is done by the process running the async query function. In other words, only the query itself is executed by async task process. The connection must be active in the other process.
At this moment, an alternative is to use mqueue+rtimer, to pass the query from sip worker process to rtimer process, which then executes the query.
Cheers, Daniel
On 23.02.22 03:06, Alex Balashov wrote:
Is there a difference in how it behaves when:
a) A database that was previously reachable becomes unreachable or unresponsive? vs.
b) A db_url that is not reachable in principle?
— Alex
On Feb 22, 2022, at 7:11 PM, Ben Kaufman bkaufman@bcmone.com wrote:
I’m not sure if this is by design or not. I have things I want to log to a SQL DB, but it’s not nearly as important as call handling, so the sql_query_async() function looked ideal, but in testing, if the DB is not responsive, the call processing gets blocked. In the example below, I’m using just a short hostname which isn’t resolvable, but if I have an IP address there that isn’t really assigned (for example if the DB server is down), the same blocking behavior is exhibited, but the error is slightly different (can’t connect instead of unknown host).
Here’s my config. This specific simple config was tested on Kamailio 5.5, but I observe similar behavior (in a more complicated config) in the dev branch as well.
#!KAMAILIO
async_workers=2
loadmodule "db_mysql" loadmodule "sqlops" loadmodule "sl" loadmodule "xlog" loadmodule "pv"
force_rport=yes
## Host sql does not resolve. modparam("sqlops","sqlcon","cb=>mysql://kamailio:kamailiorw@sql/kamailio") ## But start anyways. modparam("sqlops", "connect_mode", 1)
request_route { sl_send_reply("100", "Trying"); ## Prevent re-transmissions from the UAC
xlog("L_NOTICE", "Time before sql_query_async(): [$TV(Sn)]\n"); sql_query_async("cb", "INSERT INTO table1 (col) VALUES ('val')"); xlog("L_NOTICE", "Time before sl_send_reply(): [$TV(Sn)]\n"); sl_send_reply("404", "Not found");}
Here’s the log if I send a simple INVITE with SIPp. Note the timestamps
9(16) NOTICE: <script>: Time before sql_query_async(): [1645574694.546165] 9(16) ERROR: db_mysql [km_my_con.c:163]: db_mysql_new_connection(): driver error: Unknown MySQL server host 'sql' (-3) 9(16) ERROR: <core> [db.c:319]: db_do_init2(): could not add connection to the pool 9(16) ERROR: sqlops [sql_api.c:190]: sql_reconnect(): failed to connect to the database [cb] 9(16) ERROR: sqlops [sqlops.c:232]: sql_check_connection(): failed to connect to database 9(16) ERROR: sqlops [sqlops.c:264]: sql_query_async(): invalid connection to database 9(16) NOTICE: <script>: Time before sl_send_reply(): [1645574699.552440]
Ben Kaufman Sr. VoIP Engineer - BCM One
+1.612.735.9309 bkaufman@bcmone.com 24 hour client support: +1.855.639.6300
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-- Alex Balashov | Principal | Evariste Systems LLC
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