From: Eleanor McHugh <eleanor@...>
Date: 2009-06-22T20:27:10+09:00
Subject: Re: ruby suggestion:do_not_reverse_lookup = true as default

On 22 Jun 2009, at 11:41, Roger Pack wrote:
> Currently ruby socket code defaults to always doing a reverse DNS  
> lookup
> when it can [ex: once per incoming UDP packet].
> This causes "surprising" pauses when the lookup fails, because the DNS
> waits 15s to timeout, before passing the packet back to the program,
> since the pause is unexpected.
>
> ex: http://betterlogic.com/roger/?p=1646
> comment out the do_not_reverse_lookup on the receiver and change the
> sender to send to IP127.0.0.255
>
> It works great [no pause]if you set  
> BasicSocket.do_not_reverse_lookup to
> true, and is much less surprising.  This isn't the first time I've  
> been
> bit by ruby's internal packet DNS lookups and so thought I'd ask for
> feedback before suggesting to core that it be turned off by default.
>
> The other benefit is that with DNS lookups, sometimes they succeed,  
> and
> sometimes fail, which means that normal code could run into unexpected
> pauses when put into production--which is surprising and unwanted,
> really.
>
> Thoughts on this one?
> Thanks.

I tend to agree with you on this although I'd also suggest that the  
option become do_reverse_lookup if it's going to default to false,  
that avoids having to read lots of code peppered with  
do_not_reverse_lookup = false when a reverse lookup is desired. Double  
negatives are a guaranteed way to scramble frazzled brains :)


Ellie

Eleanor McHugh
Games With Brains
http://slides.games-with-brains.net
----
raise ArgumentError unless @reality.responds_to? :reason