Re: Support for 1RTT multi-queries over TCP (or lack thereof)

In order to achieve parallelism you seem to desire, the transactions need
to be mutually order independent.

You will first need to free yourself from the ordering imposed by the TCP
stream; a mighty TCP river with many sockets, the TCP equivalent of the
Nile delta.  Just the thing for DOS attacks!

Perhaps disappointment(1) would be better directed at adns for offering
what it is unable to deliver.

Disappointment(2) would be justified only if the computational cost of the
occasional wasted queries exceeded the cost of monitoring connections which
are rarely dropped.



Dick Franks
________________________



On 18 December 2013 12:18, Tony Finch <[email protected]> wrote:

> I saw a message to the unbound-users list which says unbound processes TCP
> queries sequentially.
>
>
> http://unbound.nlnetlabs.nl/pipermail/unbound-users/2013-December/003096.html
>
> I thought this was disappointingly poor, especially wrt the recent
> discussion about backwards-compatible alternatives to edns-chain-query. So
> I did a quick test to see if BIND has the same problem. I shoved a few
> entries from the Alexa Top 1 Million list into adns as follows.
>
> $ sed 's|^[0-9]*,||;s|/.*||' top-1m.csv | head -100 |
>   adnshost --cname-loose --asynch --pipe
>
> Over UDP you can clearly see the response serial numbers are out-of-order,
> and the whole thing runs in about 3 seconds with a cold cache.
>
> If I add --tcp to the adnshost command line the responses come back
> strictly in order and BIND processes them one at a time. Processing all
> the queries takes more than 30 seconds, so adns times out before getting
> responses to the last 25 queries. (When you invoke adnshost like this it
> does not by itself do anything to limit the number of outstanding
> queries.) In addition to that, named fails to notice that the TCP socket
> has gone away and continues to process queries. (I will report this as a
> bug.)
>
> So that is doubly disappointing.
>
> Tony.
> --
> f.anthony.n.finch  <[email protected]>  http://dotat.at/
> Forties, Cromarty: East, veering southeast, 4 or 5, occasionally 6 at
> first.
> Rough, becoming slight or moderate. Showers, rain at first. Moderate or
> good,
> occasionally poor at first.
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