[asterisk-users] CEL entries over ODBC several hours late (Matthew Jordan)

[Stefan Viljoen]

Hi Matthew

Thank you very much for the reply.

I must have something seriously wrong somewhere else then - I retested now
and the "apparent" effect is as  I describe but your info definitely
contradicts that. But you're obviously correct.

One more question - I've noted that if I run a combination of queries in the
CEL backing DB (MariaDB) and the CEL table is locked, this severely affects
the Asterisk instance - thousands of occurrences of

chan_sip.c:4057 __sip_autodestruct: Autodestruct on dialog
'6a9f5d3543b619655e07c81437373a32 at 172.17.12.3:5060' with owner
SIP/3034-000207c8 in place (Method: BYE). Rescheduling destruction for 10000
ms

appear in the CLI and users complain that if they hang up then they cannot
make another call on the same SIP handset for several minutes.

This is obviously because the dialplan gets delayed in the H extension, and
cannot write to the CEL table, waiting for the MariaDB instance to clear the
locks so it can write again. The above apparently comes from a watchdog
process that watches how "fast" the H extension is and if it takes "too
long" it forces the channels closed.

Is this assumption correct?

Addtionally, it seems that the writing of CEL in Asterisk is NOT async? E.g.
it appears the thread that was running the conversation ALSO does the CEL
writing / pushing to the CEL core as you describe in a synchronous manner.

For 1.8, is this correct that CELs are synchronous, and do newer Asterisk
versions do it async?

E. g. my point being if there are major DB issues, it is quite a bit
kryptonite to have that "spill back" into Asterisk and start blocking off
users from calling out - wouldn't it be much better to simply have failed
CEL writes just die in a distal thread instead of the main call thread for
the channels running on that handset.

Or am I completely misunderstanding things?

Anyway, thanks for the reply. :)

Kind regards,

> Hi guys
>
> I'm running 1.8.32.3 with CEL logging over ODBC to MariaDB 5.5.41 on the
> same Centos 7 machine.
>
> I've noticed that the CDR entries made are all in-time, e. g. the call
will
> take place and the CDR entry is immediately written into the CDR table in
> the MariaDB database.
>
> However, CEL events for that CDR (which I need to process for a realtime
> display feature in my dialer software) are always several hours after the
> fact. E. g. I will make a call at 09:30, see the call immediate pop up in
> the MariaDB CDR table, but only at about 15:15 that afternoon will I see
> that call's CEL events come into the CEL table, from Asterisk.... I have
> examined the `show processlist` in MariaDB exhaustively to establish this
> fact.
>
> The system doesn't appear loaded, load average is about 1.1 - it's a
> quad-coare HT Intel Xeon E3-1225 with 8GB of DRAM running on an SSD for
> main
> storage.
>
> The system processes about 30 000 calls every 8 hour day, and services 90
> SIP phones.
>
> I can stop and restart the MariaDB instance for several minutes, when I
> restart it it immediately picks up on the "slow" CELs from where it was
> interrupted - more evidence that Asterisk is very slowly streaming the
CELs
> through. I thought MariaDB was the bottleneck, but apparently not?
>
> If I make test inserts from a script into the CEL table, all of them
> complete so quickly a time indication does not even register for the query
> in MariaDB. Simple test queries on the CEL table are also instant, not
even
> counting in the internal MariaDB query duration timer.
>
> Can anybody explain why this is that the CELs asterisk emits over ODBC are
> so delayed? Are CELs intended NOT to be realtime?
>
> So, logically, Asterisk appears to be caching CELs to the tune of hundreds
> of thousands of them at any given time - meaning if it is stopped (either
> killed, or core stop gracefully'ed, or just "core stop now")  potentially
> hundreds of thousands of CELs will just evaporate irretrivably.
>
> What can I do to mitigate this extremely slow populating of CELs over
ODBC?
>
>
Asterisk does not buffer CEL entries. If anything, it pushes the entries
out to ODBC much more aggressively than what you would get with CDRs.

An event is generated in Asterisk that corresponds to the CEL entry. That
entry is pushed over a message bus (the 'event' message bus in 1.8 - 11;
'stasis' in 12+) and is picked up by the CEL core. The events are
immediately sent to the registered backends, who also immediately write it
out to the backend they support. In the case of ODBC, this immediately does
an INSERT into the appropriate table.

In Asterisk 1.8, you can look for a verbose level 11 message that will show
when this occurs:

        ast_verb(11, "[%s]\n", ast_str_buffer(sql));

In later versions, this was turned into a debug level 3 message (as
anything over a verbose 5/debug 5 was cleaned up).

If you see that message, then that will tell you when Asterisk *believes*
it has written the CEL entry. If that doesn't show up in the database, then
it is either in the ODBC driver or the Maria database.

If you don't see that message, then something is preventing those events
from getting delivered inside of Asterisk, which would only occur if you
had some other serious call related issues occurring.

Matt