9.2.5 db causes high cpu? was: Re: BIND 9.2.5rc1 is now available.

Brad Knowles brad at stop.mail-abuse.org
Mon Feb 21 19:59:02 UTC 2005

At 5:29 PM +0000 2005-02-21, Paul Vixie wrote:

>  my very brief understanding of why CNS is so fast is that the authors put
>  some time and thought into understanding how to do retries and server
>  selection (from among multiple NS's each having multiple A's and AAAA's)
>  correctly.

	That may make them faster in terms of end-to-end performance of a 
given query, but I don't know whether or not that specific aspect 
would show up in the benchmark testing I've done.  I believe that 
there may be other factors involved.

>  the data structures are also optimized for the job at hand -- and not
>  having authority zones or views in the way is a great simplifier.  but
>  if that was the only difference, then djbdns would be as fast as CNS.

	Data structures and internal architecture changes are the sort of 
thing I'd expect to see as showing up in my testing.

	And just so that everyone here is clear, my testing shows that 
djbdns is a dog in terms of performance.  A dead dog at that.

>  there is a lot of interest out there in persistent dns caching, and in
>  what some people call "dns mirroring" that's really just a persistent
>  dns cache with search/dump capability.  at some point BIND will have
>  to support this, whether by SQL or DB or whatever means.

	Persistent DNS caching/mirroring is easily done by setting up a 
stealth secondary for the zone.  I've done that for some of the big 
black lists while working at various former employers.

	But then that gets back into the mixing of recursive and 
authoritative modes.  ;(

>  according to internal lab results i've seen in the last year, that's
>  just not true.  i don't think BIND9 will be beating ANS any time soon,
>  but if we can figure out how to do the release engineering for all the
>  stuff in the CVS pool, i think we'll be competitive with everybody else.

	That would be very cool.  I really would love to see that.

>  i mostly agree.  this mailing list was dead for a long time, and i'm happy
>  that it stopped being dead a week or so ago.  more community involvement
>  is a good thing.  more community source code submissions is a good thing.

	Would that I could contribute code.  Regretfully, I haven't done 
any real programming since graduating college in 1989, and looking 
back on it, I don't think you could consider what I did back then to 
be "real programming", either.

	I can hack a bit on things like scripts, and I can put together 
testing profiles that I consider to be reasonably decent.

Brad Knowles, <brad at stop.mail-abuse.org>

"Those who would give up essential Liberty, to purchase a little
temporary Safety, deserve neither Liberty nor Safety."

     -- Benjamin Franklin (1706-1790), reply of the Pennsylvania
     Assembly to the Governor, November 11, 1755

   SAGE member since 1995.  See <http://www.sage.org/> for more info.

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