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List:       apache-httpd-dev
Subject:    Re: mod_proxy and AAAA queries
From:       Jeff Trawick <trawick () attglobal ! net>
Date:       2003-02-28 17:52:35
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Chris Monson wrote:

> I have noticed that mod_proxy, in its apr_sockaddr_info_get calls uses
> unspecified resolution and sends it no flags.  This, of course, allows
> the APR to make the decision as to how to resolve the hostname, but it
> causes some truly amazing slowdowns when AAAA authorities are not
> available for particular hosts (for example, toolbar.aol.com).  The AAAA
> requests must time out before the A request can be made.
>
> To solve this problem, I am interested in patching mod_proxy and
> friends, creating a new configuration directive, something like
> ProxyResolutionType (or order).  This would take a list of parameters
> indicating which kinds of queries will be tried, and would map to flags
> passed into apr_sockaddr_info_get.  Doing this would allow me to specify
> that I *never* want to make AAAA queries or A6 queries (or to specify
> that I want to make them after trying the currently more common A 
> queries).


+1, this is exactly why the capability was first added to 
apr_sockaddr_info_get() in the first place...  it is in my to-do list, 
but you know how that goes :)

my original thought, and some discussion on dev@httpd agreed I think, 
was to try to have a server-wide setting that more than just proxy could 
look at...  in a pure IPv4 or pure IPv6 environment, there is no use in 
any extra processing anywhere, unless of course it is config-time 
processing that is not performance-sensitive


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