[Pdns-users] pdns-recursor impact of lua script

bert hubert bert.hubert at netherlabs.nl
Thu Mar 13 20:11:46 UTC 2014

On 13 Mar 2014, at 20:07, ktm at rice.edu wrote:

> Hi PDNS community,
> I have a quick question about the impact of lua scripts on the recursors
> performance. If occasionally a script needs to perform more processing for
> a particular request, does that lookup/lua processing block or slow up
> other queries in progress or new lookups?

Hi Ken,

If you block in Lua, that recursor thread will come to a standstill. If you run with threads=2, the other thread will continue of course. But the idea of the Lua scripts is that they are synchronous.

Having said that, Lua is very performant and we’ve heard reports of giant Lua scripts doing MD5 hashes & lookups not causing problems.

In addition, we have some infrastructure for ‘handing off’ queries from Lua for further processing, if you want, let us know what you want to achieve off list, and maybe what we have could be a fit for you. 

Good luck!


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