Good evening,

I got the LuaSQL postgres driver working and ran the same example:
require "luasql.postgres";
 
local env = assert(luasql.postgres())
local con = assert(env:connect("db", "user","pass","172.31.0.5"))
local cur = assert(con:execute ("select 1 as foo, 2 as bar"))
 
local row = {}
while (cur:fetch(row, "a")) do
  for key, val in pairs(row) do
    stream:write(string.format("%25s : %s\n", key, val))
  end
  stream:write("\n")
end
 
cur:close()
con:close()
env:close()
And did the same test:
freeswitch@fs-dev> hammer 1000 lua test_luasql_postgres.lua
+OK Finished in 40625 ms (min 30 ms, max 122 ms)
So it's slowest of the three ! :-) - I didn't investigate any further about the cause of this.

I ran it a couple of times with the same result, and it was done on the same machine.

(for completeness sake: all tests were done on an Intel Q6600 with two KVM guests, one containing an Ubuntu 10.04/64 with Postgres 8.4 and one guest with CentOS 5.5/64 with FS Trunk)

-- To answer your other question about whether it blocks:

The FreeSWITCH cache db behaves in a way that it makes a new connection if there are no free handles in the pool. It will only block if your db server doesn't allow a new connection. In c, you should normally release your db handle manually, but Lua has garbage collection, that automatically triggers release of any db handles to the pool when they go out of scope (for example when your script terminates). If a free handle is available in the pool it will be re-used by another thread.

If I understand it right, a free handle in the pool will be disconnected from the db server if it is not used for 120 seconds.

Kind regards,

Leon




Op 9/28/2010 4:10 PM, Leon de Rooij schreef:
Hi Bernhard,

I tried out several ways for connecting to a database from inside FreeSWITCH myself before writing the freeswitch.Dbh (which is rather simple actually - it only exposes already existing FreeSWITCH functionality in mod_lua).

My findings were that caching the connection as is provided by FreeSWITCH gives a huge speed increase compared to re-connecting all the time as must be done with LuaSQL. Perhaps there are ways to have a connection pool in ODBC but I didn't investigate that.


Here's a test with LuaSQL with ODBC driver:
require "luasql.odbc";
 
local env = assert(luasql.odbc())
local con = assert(env:connect("dsn","user","pass"))
local cur = assert(con:execute ("select 1 as foo, 2 as bar"))
 
local row = {}
while (cur:fetch(row, "a")) do
  for key, val in pairs(row) do
    stream:write(string.format("%25s : %s\n", key, val))
  end
  stream:write("\n")
end
 
cur:close()
con:close()
env:close()

            
freeswitch@fs-dev> hammer 1000 lua test_luasql_odbc.lua

            
+OK Finished in 38952 ms (min 29 ms, max 107 ms)

          

        

      

      

        

          


          

          


          

          
The same test with freeswitch.Dbh:

          


          

          

            
local dbh = assert(freeswitch.Dbh("dsn","user","pass"))
 
assert(dbh:query("select 1 as foo, 2 as bar", function(row) 
  for key, val in pairs(row) do
    stream:write(string.format("%25s : %s\n", key, val))
  end
  stream:write("\n")
end))
 
assert(dbh:release())

          

          


          

          

            
freeswitch@fs-dev> hammer 1000 lua test_lua_dbh.lua
+OK Finished in 2723 ms (min 1 ms, max 25 ms)


          

          


          

          
As you can see, with these tests the freeswitch.Dbh is
            about 14 times as fast as luasql.odbc. Of course this test
            is single threaded (the scripts are executed serially), so
            you'd get different results in real-world, and if you have
            'long' running scripts with many queries on the same handle,
            the results would even out a bit.

          


          

          
(btw mod_hammer is a simple app in contrib/ledr/c that
            executes another app n times and shows how long it took)

          


          

          
I just tried compiling LuaSQL with Postgres driver to do
            the same tests, but that borked. Maybe you can give results
            of that ? I am curious how it behaves.

          


          

          
About having a native driver or odbc: odbc is just an
            abstraction layer which uses the native drivers itself, so
            I'd reckon it should be almost as fast - correct me if I'm
            wrong ?

          


          

          
I wrote some more about these tests on my blog at http://www.toyos.nl

          


          

          
Kind regards,

          


          

          
Leon

          


          

          


          

          
On Sep 16, 2010, at 8:52 PM, Bernhard Suttner wrote:

          

          

            
Hi,

              

              from performance point of view, what should be used to
              connect to many different databases, luasql or
              freeswitch.dbh which does use ODBC?

              

              The problem is, that is not only one database but 3-5
              databases which are on 2-3 different hosts. Lua will be
              used to fetch the directory and dialplan directly from the
              db. Also live-data will be stored on the different
              databases. The advantage of freeswitch.dbh would be, that
              the db connections will be re-used. LUAsql would use the
              native e.g. postgres or mysql driver.

              

              Thanks for any hint. 

              

              Best Regards,

              Bernhard

              

              _______________________________________________

              FreeSWITCH-dev mailing list

              FreeSWITCH-dev@lists.freeswitch.org

http://lists.freeswitch.org/mailman/listinfo/freeswitch-dev

UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch-dev

              http://www.freeswitch.org

            

          

        

        

      

      

_______________________________________________
FreeSWITCH-dev mailing list
FreeSWITCH-dev@lists.freeswitch.org
http://lists.freeswitch.org/mailman/listinfo/freeswitch-dev
UNSUBSCRIBE:http://lists.freeswitch.org/mailman/options/freeswitch-dev
http://www.freeswitch.org