Comparing query rates (was Re: 9.2.5 db causes high cpu?)

Paul Vixie paul at
Tue Feb 22 16:52:41 UTC 2005

> >                                              I know some name servers
> > (PowerDNS?) maintain a cache of recent answers in wire format and can
> > simply bit-copy the response without doing a lookup and marshalling
> > the data for a reply if the same query is repeated. Maybe BIND9 will
> > do this one day.
> It is PowerDNS indeed.
>  ->
> License issues:
> Since PowerDNS is GPL now, it there any legal way to 'steal' portions
> of this code and distribute it under BIND-License or as an addon or
> patch set under GPL?  I think this would be a great thing to have with
> BIND no matter the license.

what we have running in an unreleased cvs branch somewhere is the ability
to cache the additional-data sections of recent responses, since that's
where the majority of bind9's cpu time and memory bandwidth was going.
the speedup was good but of course the memory utilization goes up if you
turn on this feature.  we're still investigating and will integrate and
ship it in some form eventually.

> > Running the latest code is usually the best policy. It will have the
> > old bugs fixed. And it'll no doubt have new bugs. :-) IMO the new
> > features in 9.3 are well worth the upgrade price on their own.
> That was not really the answer to my question but it was an answer.
> You're appreciated.

more to the point, i don't know of any recursive-query performance
enhancements between 9.2.x and 9.3.0, so if that was your only reason
for upgrading, don't bother.  but you have many other and better reasons
for upgrading, as pointed out by jim above.

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