[asterisk-bugs] [JIRA] (ASTERISK-27615) Dialplan deadlock when connection to external SQL server is lost

[Jared Hull (JIRA)]

    [ https://issues.asterisk.org/jira/browse/ASTERISK-27615?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=241827#comment-241827 ] 

Jared Hull commented on ASTERISK-27615:
---------------------------------------

Ok, I've got a good idea about what is going on now.
When Asterisk finalises CDR with {{odbc_log() from cdr_adaptive_odbc.c}} or executes a dialplan ODBC_ function with {{func_odbc.c}}, it calls {{connection_dead() from res_odbc.c}}. This function calls {{SQLGetConnectAttr() from libmyodbc5.so}} to get the resulting attribute of SQL_ATTR_CONNECTION_DEAD, then it calls {{mysql_ping() from libmysqlclient.so.18}} which doesn't return unless I restore networking on the SQL server. There might be a bug in a SQL library I am using.

That aside, I don't think asterisk should be hanging on subsequent ODBC_ dialplan functions and CDR() gets/sets.

> Dialplan deadlock when connection to external SQL server is lost
> ----------------------------------------------------------------
>
>                 Key: ASTERISK-27615
>                 URL: https://issues.asterisk.org/jira/browse/ASTERISK-27615
>             Project: Asterisk
>          Issue Type: Bug
>      Security Level: None
>          Components: CDR/cdr_adaptive_odbc, Functions/func_cdr
>    Affects Versions: 14.6.0
>            Reporter: Jared Hull
>            Assignee: Unassigned
>            Severity: Critical
>         Attachments: core-asterisk-running-2018-01-26T17-11-24+0000-brief.txt, core-asterisk-running-2018-01-26T17-11-24+0000-full.txt, core-asterisk-running-2018-01-26T17-11-24+0000-locks.txt, core-asterisk-running-2018-01-26T17-11-24+0000-thread1.txt
>
>
> We have a cluster of SQL servers for CDR and realtime states that are used in dialplan. Recently we had a single SQL server lose network connectivity, and all Asterisk instances which used this server as their primary started to hang in dialplan.
> If I stop the SQL service while leaving the server pingable, Asterisk will continue to work and simply return a few errors when the CDR is committed to the database.
> {code}
> res_odbc.c:962 odbc_obj_connect: res_odbc: Error SQLConnect=-1 errno=2003 [unixODBC][MySQL][ODBC 5.2(w) Driver]Can't connect to MySQL server on 'dev-dallas-sql1
> cdr_adaptive_odbc.c:436 odbc_log: cdr_adaptive_odbc: Unable to retrieve database handle for 'dev-dallas-sql1:cdr_event_log'.  CDR failed: INSERT INTO cdr_event_log (
> {code}
> If I 'service network stop' on the SQL server to simulate network failure, asterisk stops executing dialplan related to func_odbc and cdr_adaptive_odbc. It is as if it still thinks the SQL connection is there, and refuses to failover to another DSN in the case of func_odbc. cdr_adaptive_odbc doesn't even have failover connections (this would be a very useful feature) so I don't know what can be done about that, other than to skip CDR and throw an error.
> Dialplan to reproduce:
> {code}
> exten => 101,1,noop(${CDR(anything)})
> exten => 102,1,noop(${ODBC_blacklist_global(42)})
> {code}
> Example of cdr_adaptive_odbc.conf entry:
> {code}
> [default]
> connection=dev-dallas-sql1
> table=cdr_event_log
> {code}
> Example of func_odbc.conf entry:
> {code}
> [blacklist_global]
> dsn=dev-dallas-sql1,dev-dallas-sql2,dev-dallas-sql3
> readsql=SELECT COUNT(*) FROM blacklist_global WHERE cid_number='${SQL_ESC(${ARG1})}'
> {code}



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