[bind10-dev] new in-memory zone data design

[Likun Zhang]

So, am I lost?  Or do we get a final conclusion for the next step of
in-memory zone data design?


> -----Original Message-----
> JINMEI Tatuya / ÉñÃ÷ß_ÔÕ
> Sent: Saturday, June 30, 2012 2:30 AM
> To: Peter Koch
> Cc: bind10-dev at lists.isc.org
> Subject: Re: [bind10-dev] new in-memory zone data design
> 
> At Fri, 29 Jun 2012 19:25:35 +0200,
> Peter Koch <pk at DENIC.DE> wrote:
> 
> > > The upside is that for large zones with mostly the same TTL, you save
4
> > > bytes per RdataSet. The downsides are that you have to figure out
> what
> > > that TTL is, and also for zones with multiple TTL you don't get any
> > > benefit. (Possibly you could try to optimize for zones with a small
> > > number of TTL, which is probably most zones, but that probably goes
> too
> > > far on the complexity level.)
> >
> > set alert='bikeshed'
> >
> > I'd be interested in the penalty, if any, that means for zones with non-
> > uniform TTLs.  There's already a case to distinguish between A/AAAA
> > and infrastructure data and I'd rather not see future DNS extensions
> > making TTL 'requirements' based on the performance argument.
> > Also, NSEC/NSEC3 and their RRSIGs usually have a different TTL than
> 'positive'
> > RR types.
> 
> Apart from how common it is to have different TTLs in a zone, I'd note
> (or repeat) that in terms of memory-efficiency saving 4 bytes can be
> moot for 64-bit machines (which I guess are more common today for
> large scale operators where this kind of discussions matter).
> 
> > > Ah, wildcards. I'm quite happy if zones using wildcards are less
> > > efficient than "normal" zones. I don't think we need to kill ourselves
> > > to optimize for a feature not used *so* commonly, and not at all for
> > > performance-critical zones, AFAIK.
> >
> > Guilty as charged.  There are lots of wildcards in DE, albeit not
> immediately
> > under teh top level label.  However, there are lots of servers that
serve
> > large numbers of (small) zones that do contain wildcard owners.
> 
> Hmm, interesting.  Do you know how often these wildcard records are
> used in DE?  In the case of large-#-of-small zones, I guess it also
> depends on the expected total response performance.  I guess the
> vast majority of the small zones are very minor in such cases, and if
> the requested overall performance is moderate the additional overhead
> due to wildcards can be less substantial.
>