[sr-dev] accessing database from a child forked proces
Luis Azedo
luis.azedo at factorlusitano.com
Mon Sep 8 15:29:43 CEST 2014
Hi Daniel,
all problems solved with presence! i was not running child_init and now
there is no need for the proposed patch to presence.
Thank you
On Mon, Sep 8, 2014 at 2:13 PM, Luis Azedo <luis.azedo at factorlusitano.com>
wrote:
> Hi Daniel,
>
> this is the way we are creating the child processes (1 manager and n
> workers)
> the problem is with the workers.
> the worker will call a event-route and in the script config we try to call
> pres_refresh_watchers and that's where we get the pa_db = NULL.
>
> as i understand from your email, if we change PROC_NOCHLDINIT and let the
> child_init execute for the forked process then it will also execute
> child_init in other modules ? it makes sense.
>
> going to try this.
>
>
> static int mod_child_init(int rank)
> {
> int pid;
> int i;
>
> fire_init_event(rank);
>
> if (rank==PROC_MAIN) {
> pid=fork_process(PROC_NOCHLDINIT, "AMQP Manager", 1);
> if (pid<0)
> return -1; /* error */
> if(pid==0){
> kz_amqp_manager_loop(0);
> }
> else {
> for(i=0; i < dbk_consumer_processes; i++) {
> pid=fork_process(PROC_NOCHLDINIT, "AMQP Consumer", 1);
> if (pid<0)
> return -1; /* error */
> if(pid==0){
> mod_consumer_proc(i+1);
> }
> }
> }
> }
>
> return 0;
> }
>
>
>
> On Mon, Sep 8, 2014 at 1:11 PM, Daniel-Constantin Mierla <
> miconda at gmail.com> wrote:
>
>> Hello,
>>
>> the database connection should not be shared beween processes, because it
>> can bring unexpected results in may places.
>>
>> Right now, the rule is to have one connection per process, shared by all
>> modules in that process.
>>
>> To achieve that, at mod_init each module opens database connection and
>> closes it before ending the function. Then in child_init() the connection
>> is opened again. Another module that will have to open in child_init() will
>> get the same connection now.
>>
>> When you create a new process, you tell the type of child and based on
>> that child_init() from the other modules are executed.
>>
>> What is the function do you use for creating a new process? Maybe you can
>> paste it here exactly how you do it and I can see if something can be done.
>>
>> Cheers,
>> Daniel
>>
>>
>> On 03/09/14 12:09, Luis Azedo wrote:
>>
>> Hi Jason,
>>
>> thanks for the reply.
>>
>> the last 2 statements in presence module mod_init close the connection
>> and set pa_db to NULL. when my module main process forks the extra
>> processes the pa_db in presence is NULL, so when it calls
>> pres_refresh_watchers it fails because pa_db is NULL.
>> i commented these last statements in presence mod_init and i got it to
>> work.
>>
>> // pa_dbf.close(pa_db);
>> // pa_db = NULL;
>>
>> does this have any implications on how the module works ? is it ok to
>> merge this change ?
>>
>> Thank you
>>
>>
>>>
>>> ----------------------------------------------------------------------
>>>
>>> Message: 1
>>> Date: Sun, 31 Aug 2014 09:40:49 +0200
>>> From: Jason Penton <jason.penton at gmail.com>
>>> To: "Kamailio (SER) - Development Mailing List"
>>> <sr-dev at lists.sip-router.org>
>>> Subject: Re: [sr-dev] accessing database from a child forked process
>>> Message-ID:
>>> <
>>> CALoGXNWvHhCAO91Tfa0w8W3eYQRvfV7Qkgte7dBnD+ciNr_Kpg at mail.gmail.com>
>>> Content-Type: text/plain; charset="utf-8"
>>>
>>> To confirm exactly what processes are being used, maybe check the log
>>> file
>>> and take note of process id at each log event. For example you could
>>> check
>>> the process id of the messages showing you the connection is null. Then
>>> run
>>> kamcmd ps to show the process list with a description of each Kamailio
>>> process. That will probably point you in the correct direction.
>>>
>>> Cheers
>>> Jason
>>>
>>>
>>> On Fri, Aug 29, 2014 at 3:53 PM, Luis Azedo <
>>> luis.azedo at factorlusitano.com>
>>> wrote:
>>>
>>> > Hi,
>>> >
>>> > i have a module that creates 1 extra process where it processes stuff
>>> in a
>>> > loop.
>>> > on some condition i fire a route_event with a fakemsg and its up to the
>>> > user of the module to take action, it tries to work like dispatcher
>>> module
>>> > or htable (mod-init) events.
>>> >
>>> > the problem that i have is that, if i call some function on some module
>>> > that performs a database action, the connection is null when it calls
>>> > use_table.
>>> >
>>> > in this case i'm making this call
>>> > event_route[my_module:my_event]
>>> > {
>>> > $var(my_uri) = <<result of some operations>>;
>>> > pres_refresh_watchers("$var(my_uri)", "dialog", 1);
>>> > }
>>> > presence module makes the call to use_table but this call fails because
>>> > the connection is null. presence module is working fine besides this.
>>> >
>>> > if i make this call inside event_route[dispatcher:dst-up] it works.
>>> >
>>> > i think that dispatcher fires the event inside a callback from a
>>> > registered timer, so, i think (may be wrong) that it comes from a
>>> different
>>> > process ?
>>> >
>>> > i wonder if i'm missing something from child_init ? need to register
>>> > something ?
>>> >
>>> > thanks for your help.
>>> >
>>> >
>>> >
>>> >
>>> >
>>> >
>>> > _______________________________________________
>>> > sr-dev mailing list
>>> > sr-dev at lists.sip-router.org
>>> > http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-dev
>>> >
>>> >
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>>
>>
>>
>> _______________________________________________
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>>
>>
>> --
>> Daniel-Constantin Mierlahttp://twitter.com/#!/miconda - http://www.linkedin.com/in/miconda
>> Next Kamailio Advanced Trainings 2014 - http://www.asipto.com
>> Sep 22-25, Berlin, Germany
>>
>>
>
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