Hi,

I'm using the following Lua-Script to check whether a conference exists and only let a caller join if so.
The script is called via the following dialplan <action application="lua" data="/path/to/script.lua $1" /> , where $1 is the destination number.


  1. -- Connect to a database
  2. local dbh = freeswitch.Dbh("pgsql://hostaddr=127.0.0.1 dbname=database user=username password='password' application_name='my-lua-script'")
  3. assert(dbh:connected());
  4. -- Execute SQL
  5. dbh:query(string.format("SELECT COUNT(*) as \"MyCount\" FROM \"MyTable\" WHERE ColA = '%s'", argv[1]), function(row)
  6.     --freeswitch.consoleLog("INFO", "Results: " .. row.MyCount)
  7.    
  8.     dbh:release()
  9.    
  10.     if (row.MyCount== '1') then
  11.         freeswitch.consoleLog("INFO", "User is joining conference at " .. argv[1])
  12.        
  13.         session:answer()
  14.         session:execute("conference", argv[1] .. "@wideband")
  15.     end
  16.     session:hangup()
  17. end)

Line 8 instructs FS to return the postgres-Connection back to the pool - which is as expected. When a user now leaves the conference, FS throws this errors:

2014-10-12 10:32:30.065924 [DEBUG] switch_cpp.cpp:694 CoreSession::hangup
2014-10-12 10:32:30.065924 [CRIT] switch_pgsql.c:368 An error occurred trying to consume input for query (200): connection pointer is NULL
2014-10-12 10:32:30.065924 [CRIT] switch_pgsql.c:122 No DB Connection
2014-10-12 10:32:30.065924 [ERR] switch_core_sqldb.c:1177 ERR: [SELECT COUNT(*) as "MyCount" FROM "MyTable" WHERE ColA = 'conf-1234'][connection pointer is NULL]
2014-10-12 10:32:30.065924 [ERR] freeswitch_lua.cpp:446 DBH NOT Connected.
2014-10-12 10:32:30.065924 [DEBUG] switch_cpp.cpp:1075 sofia/internal/Alice@my.pbx.com destroy/unlink session from object

Now, I could live with that. BUT: The problem is, that sometimes, when a user leaves the conference, FS crashes.
I've narrowed down the main cause to the above lua script. If I comment line 8 out, FS stops crashing. This will also stop FS from reusing Database-Connections.

Now my questions:
  1. I don't use `dbh` after line 8. So where does the error come from?
  2. How can I stop the error?
  3. How can I rewrite the lua script to have both a) non-crashing FS and b) reusing of connection?


Regards,
Bernhard