[Pdns-users] pdns recursor - unthreaded vs threaded operation

[Fabio Sangiovanni]

Hi Bert,

are you planning to run multiple Lua sessions per thread in the future (in PowerDNS Recursor)?
If yes, do you think it will be possible to have a switch for this feature in recursor.conf?
I need to make a decision for my company about the use of PowerDNS Recursor in a project and everything depends on the possibility of having one single lua session per thread.

Thanks a lot for your support.

Cheers,
Fabio

Il giorno 30/dic/2011, alle ore 09:43, bert hubert ha scritto:

> On Thu, Dec 29, 2011 at 08:55:57AM +0000, Fabio Sangiovanni wrote:
>> am I right thinking this would solve my problem?
> 
> For now, and for this version of the PowerDNS Recursor, if you set threads
> to 1, you will really only get 1 simultaneous Lua session.
> 
> However, this is not true in other parts of PowerDNS. In the authoritative
> server if you set 'distributor-threads=1' you might still get several
> parallel database connections. 
> 
> If you are going to do synchronous SQL updates from Lua, do realize that these
> typically cost up to a millisecond including latency.
> 
> This means that your Resolver will peak at 1000 qps.
> 
>> how deep is the impact on performances changing the number of threads from
>> 2 (default setting) to just 1?  are there other sensible settings that I
>> could adjust to better suit my needs?
> 
> You might want to look at other ways of doing statistics if you truly want
> high performance.
> 
> PowerDNS right now does not offer a good interface for very rapid query
> logging, but perhaps you could use a textfile from Lua.
> 
> Good luck!
> 
> 	Bert
>