[SR-Users] [sr-dev] dialog module with DB Backend

Wed Mar 5 03:52:57 CET 2014

Hi All,

so Ive done what Carlos suggested and swapped out my dialog db to Mysql
rather than cassandra.
All worked 100% as you would expect.

Right so the issue is db_cassandra .

I started testing and going through the code.

I found I had these lines, which was interesting & concerning.
update_dialog_dbinfo_unsafe(): could not add another dialog to db
I had been ignoring them, because the dialog was in the DB and I figured I
would come back and figure that out later.

but this seems to have been key to this whole thing.

ends up that in dlg_db_handler.c dialog_dbf.insert was getting a 1 back
from kamailio on the insert and a 0 back from mysql... WTF.. ok.

so I trace into db_cassa_insert which calls db_cassa_modify ..
around line 1210 I can see this ..

CON_CASSA(_h)->con->batch_mutate(CFMap, oac::ConsistencyLevel::ONE);
return 1;

wrapped in a try / catch block..
seems db_cassandra wants to return 1 for success but kamailio ( or dialog
module at least ) expects 0 for success .

so I change that to be return 0, and re-test.
everything works as expected,    "could not add another dialog to db" stops
coming up on my console,
and dialogs are removed when calls hangup.

seems this 1 thing is enough to screw dialogs in cassandra ( and who knows
what else ).
This is the reason for my email though,   if we simply change that to 0,
what else may break !??

however http://www.asipto.com/pub/kamailio-devel-guide/#c09f_insert clearly
states that "0 if everything is OK"
so this is clearly a bug that needs fixing.

Can I get someone with more experience to test this for me and possibly
apply the attached patch !?

Jay

On 25 February 2014 05:58, Daniel-Constantin Mierla <miconda at gmail.com>
wrote:
>
> Hello,
>
> I pushed some patches to the master branch in order to remove the dialog
from its associated profiles when it gets in terminated state. I
encountered such issue (not that) recently, but I haven't gotten the time
to get to it before.
>
> Then, the second patch is to not add dialogs in profiles when loading
from database and the state is terminated (5).
>
> Here are the links to the patches:
>
> -
http://git.sip-router.org/cgi-bin/gitweb.cgi/sip-router/?a=commit;h=edf61acb57ed5e8ee0ca9ec1f796e43ce993be48
> -
http://git.sip-router.org/cgi-bin/gitweb.cgi/sip-router/?a=commit;h=9b88eb7ee2d243882383a44f601baa21fd679cd5
>
> Should be straightforward to cherry pick to 4.1 (even 4.0 I expect). If
you test and all goes fine, I will backport -- here I had no time for real
testing.
>
> I plan also to not add the dialogs in memory for state terminated, but
destroy them at db load time. But this needs a bit of a review, to be sure
that all necessary callbacks are executed.
>
> On the other hand, if the dialogs are not removed from db, might be an
issue with the database driver (cassandra in this case, which is rather new
module). Do you get any syslog errors from kamailio or database server? I
expect that people would have reported such issue for other database
engines so far. Still it might be an issue, just that was not noticed...
>
> Cheers,
> Daniel
>
> On 24/02/14 11:19, jay binks wrote:
>
> So poking round the code for the dialog module....
> Im not sure what im missing here.
>
>
> get_profile_size dosnt care bout the state of a dialog... so you get ALL
dialogs that are in the hash table.
> ( which is interesting if you want to use dialog module to enforce
channel limits etc )
>
> So you go... OK...  kamailio only expects to have "ACTIVE" dialogs in the
hash table... kewl..
> lets assume that to be the case.
>
> but then in dlg_db_handler.c , load_dialog_info_from_db loads all dialogs
from the DB, regardless of state.
> so all dialogs in the DB ( ones that didnt get deleted yet... but were in
state 5 ) get re-created in kamailio
> upon startup.
>
> what this means is...
> ( assume starting with empty DB )
>
> I start kamailio, make some calls... they get synced to the DB.
> I end the calls,  kamailio removes from dialogs module internal hash, but
the sync to DB hasnt happened yet.
>
> I kill kamailio ( or crash .. whatever )....  restart kamailio and it
re-loads all those dialogs
> and thinks they are still active calls.
>
> Im SURE Im missing something here, because it seems to be VERY common to
use dialogs for channel limiting..
> maybe not so much using cassandra db behind the scenes, but as of yet ...
Im still yet to find anything that makes me thing this is db_cassandra
mis-behaving.
>
> if im wrong, please point me in the right direction.
>
> Jay
>
>
>
>
> On 24 February 2014 17:54, jay binks <jaybinks at gmail.com> wrote:
>>
>> Am I REALLY the only person who has ever run into this !?
>>
>>
>> On 19 February 2014 14:08, jay binks <jaybinks at gmail.com> wrote:
>>>
>>> Hi all, im using the dialog module with db_cassandra backend..
>>> I dont believe this issue is related to cassandra, but its worth
mentioning anyways.
>>>
>>> so... I run kamailio, make calls, see dialogs in the DB..
>>> and I Can use "kamctl mi dlg_list" and see that dialogs go away when I
hangup a call..
>>>
>>> When I query the DB Backend, I still see the queries, but they have a
state of 5.
>>> I Initially thought this was a bug, but it seems dialogs in state 5 get
cleaned up after a period.
>>> so I moved on.
>>>
>>> now , lets restart kamailio..
>>> kamailio loads all dialogs on startup, after kamailio starts I call
"kamctl mi dlg_list" again, and it shows all my dialogs from the DB.   they
DO show as "State 5"
>>> but for some reason, these dialogs appear to stick around for a long
time, and the bigger issue it causes me is that my channel limiting ( using
get_profile_size ) seems to consider these dialogs ( in state 5 ) as being
active calls.
>>>
>>> Please someone point me in the right direction... :)
>>>
>>> what am I doing wrong ?
>>> ( or is this a bug somewhere )
>>>
>>> Sincerely
>>>
>>> Jay
>>
>>
>>
>>
>> --
>> Sincerely
>>
>> Jay
>
>
>
>
> --
> Sincerely
>
> Jay
>
>
> _______________________________________________
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>
>
> --
> Daniel-Constantin Mierla - http://www.asipto.com
> http://twitter.com/#!/miconda - http://www.linkedin.com/in/miconda
>
>
> _______________________________________________
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>

--
Sincerely

Jay
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