Asterisk call processing behavior during cdr table lock

[volodyaivanets]

Hello everyone!

I’ve recently noticed interesting Asterisk behavior but was not able to dig into it deep enough.

We are using Asterisk 13.26.0. Dialplan on our system contains following priority:

Set(CDR(userfield)=${some_variable})

Call processing goes through this dialplan application just fine when I will stop MySQL server. But if I will lock cdr table from writing, calls will stuck here untill DB server will be started again or Asterisk will receive CANCEL.

I tried enabling as much logging on MySQL server as I could but could not find any activity from Asterisk during execution of mentioned line. So I was hoping that someone will know if this is correct behavior and how someone could see that Asterisk is checking cdr table lock status.

Thanks a lot!

[jcolp]

CDR handling, and updates to variables, all occur in the same thread. That means if that thread is blocked in some way (for example posting a CDR) then the rest will be blocked. There is a batching mechanism available[1] which can be enabled to defer posting of CDRs to another thread.

[1] https://github.com/asterisk/asterisk/blob/master/configs/samples/cdr.conf.sample#L47

[volodyaivanets]

Thank you for your reply! Asterisk works exactly the way you described.

I was not noticing that this happens to second and every next call after table was locket. Asterisk is waiting when it can write CDR for first call after table lock.