Re: [DNSOP] BULK RR as optional feature

Evan Hunt <each@isc.org> Wed, 29 March 2017 02:19 UTC

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Date: Wed, 29 Mar 2017 02:19:35 +0000
From: Evan Hunt <each@isc.org>
To: "Woodworth, John R" <John.Woodworth@CenturyLink.com>
Cc: John Levine <johnl@taugh.com>, "dnsop@ietf.org" <dnsop@ietf.org>
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Subject: Re: [DNSOP] BULK RR as optional feature
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On Wed, Mar 29, 2017 at 12:41:26AM +0000, Woodworth, John R wrote:
> I believe this would ultimately be less efficient than generating
> the records on the fly.

Unquestionably. This clearly wouldn't be the preferred behavior.
If the slave does understand BULK records, you'd just transfer
those.

> Assuming a relatively small range, say an IPv4 /16.  You would
> need to sweep through similar logic and load _every_single_answer_
> into memory rather than just the ones which are asked for.

Sure, that's what $GENERATE does. The generated records are then transfered
normally. You con't end up with one auth server that has generated records
and another that doesn't.

> I see no reason caching couldn't be used to hold the more commonly
> requested records in order to save on CPU. (apologies for double-neg)
> 
> Additionally, the patterns could (and most likely should) be pre-
> parsed for simpler/ lower calorie processing.

But if you have a primary that supports BULK and a secondary that doesn't,
then you have two authoritative servers for the same domain with the same
serial number but one of is saying NXDOMAIN when the other one returns a
positive answer.  This is a significant problem, and the draft ought to
address it.  (Or have I misunderstood something?)

-- 
Evan Hunt -- each@isc.org
Internet Systems Consortium, Inc.