[Freeswitch-dev] luasql or freeswitch.dbh

Tue Sep 28 11:39:47 PDT 2010

  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, valin  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 at 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, valin  pairs(row)  do
>      stream:write(string.format("%25s : %s\n", key, val))
>    end
>    stream:write("\n")
> end
>   
> cur:close()
> con:close()
> env:close()
> freeswitch at 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, valin  pairs(row)  do
>      stream:write(string.format("%25s : %s\n", key, val))
>    end
>    stream:write("\n")
> end))
>
> assert(dbh:release())
>
> freeswitch at 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
>>
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