[Mono-dev] Nagle and NoDelay for HttpWebRequest -> EnableDnsRoundRobin

[Gonzalo Paniagua Javier]

On Sat, 2009-04-11 at 04:16 -0600, M. David Peterson wrote:
[...]
>  
>         Implementing this ranges from trivial to us doing our own DNS
>         query
>         library (straightforward, I've done it in a past life).
> 
> Interesting. What would be the benefit of going the DNS query library
> route?

The only thing is having access to the TTL. For instance, if your DNS
server is djbdns/dnscache, it will always return a 0 TTL and in that
case the library would know it needs to refresh every time.

>         The trivial solution: if the client gets several IPs for the
>         server,
>         rotate through them until the DnsRefreshTimeout is hit. If
>         only one IP
>         is returned by the DNS server we're entirely in
>         DnsRefreshTimeout hands
>         since IPHostEntry does not have an associated TTL.
>         
>         I'd like to test this on windows and set up a DNS server that
>         I can
>         control to see if the trivial solution is what they do and
>         whether or
>         not they query the server again if the TTL is expired. May be
>         tomorrow.
> 
> If having access to a couple EC2 instances to use for DNS as well as
> performance testing against a highly concurrent web service such as
> SimpleDB would be helpful I'd be happy to start a few up and give you
> root access to them.  I also have a SimpleDB .NET library which has
> been designed for high performance asynchronous operations which would
> make the performance testing trivial.
> 
> Let me know if having access to any of the above would be helpful. And
> thanks! :-)

Testing the behavior wrt DNS is easier than that. I can do everything
locally. Thanks anyway.

-Gonzalo