[SR-Users] Strange application hang querying DB

[Daniel-Constantin Mierla]

Hello,

have you identified the config function that hangs? Is a sqlops function 
or something related to authentication, location, etc?

If not, then you can use benchmark module to measure the duration of 
execution of various parts of config, in this way identifying the 
function that takes too long.

You should eventually run directly with debug=3 and watch the logs in 
syslog file.

Once you tell the function taking too long, I will try to dig further to 
see if I can spot any issue.

Some other details would help:
- is the system under load or it happens only for one request and always?
- what is the operating system? I encountered many issues with selinux 
in the past, under high load or too many connections opened

Cheers,
Daniel

On 25/06/14 20:06, Tim Chubb wrote:
>
> Hi,
>
> I’m currently wracking my brains trying to deduce where an application 
> hang can be coming from.
>
> I have ported the PostGres schema to be compatible with MS Sql Server 
> and have had no issues getting a working dev environment working.  
> However when I try and use SQL Azure as the backend db as opposed to 
> SQL Server 2012 (running locally on my dev machine) Kamailio will seem 
> to hang after about 10 – 15 mins of flawless operation.  I have 
> recreated the SQL Azure schema from the working schema running on my 
> dev machine and copied all data in a 1:1 manner so I can be certain 
> it’s not a data quality issue.  I am using the same FreeTDS/UnixODBC 
> config that I am using for Asterisk realtime (which doesn’t exhibit 
> this behaviour).  The really strange thing is that I can see the 
> queries being sent by Kmailio in the freetds trace log, and the 
> response from SQL Azure, however its as if the db response handler is 
> deadlocked/hung. The kamailio process continues to work fine, and as 
> long as its not required to commiunicate with the DB all appears well 
> i.e. no error messages in the log file.
>
> This behaviour only happens when im using SQL Azure as opposed to SQL 
> Server, so there must be something causing the issue, that’s unique to 
> SQL azure as opposed to SQL Server.  As far as I can tell this is not 
> something I can create a backtrace for as no core dumps are produced, 
> as far as I can tell there is no easy way debug what the lock is.  If 
> anyone has any suggestions I would be very grateful to hear them.
>
> One thing that occurs to me is that the db_unixodbc module doesn’t 
> have half as many parameters as its equilent in Asterisk, and that 
> connection pooling may be in use, this could be a bit of a show 
> stopper AFAIK you have to disable connection pooling with SQL server, 
> certainly any of the guides I have come across configuring Asterisk to 
> work with SQL server suggests that.
>
> *Tim Chubb*
>
> Developer
>
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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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