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From "Adam Woodworth" <mirkp...@gmail.com>
Subject Re: mod_proxy race condition bug #37770
Date Mon, 22 Sep 2008 21:30:07 GMT
Sounds good, glad I was able to help.  I'll keep an eye on this in a
future httpd release.


On Sat, Sep 20, 2008 at 6:42 AM, Ruediger Pluem <rpluem@apache.org> wrote:
>
>
> On 09/20/2008 12:21 PM, Nick Kew wrote:
>>
>> On 19 Sep 2008, at 23:08, Ruediger Pluem wrote:
>>
>>> On 09/19/2008 11:24 PM, Adam Woodworth wrote:
>>>>
>>>> The problem with this is that it will also do this for connections to
>>>> the backend that timed out.  For our application, we want actual
>>>> timeouts to be caught as normal and kicked back through to the client
>>>> as a 50x error.
>>>
>>> Hm. Good point. I have to think about it, because a timeout error can
>>> justify  a repeated request (like when a firewall between frontend and
>>> backend cut the connection and now the packets are simply dropped by
>>> the firewall and a fresh one would fix this).
>>
>> I think Adam is right.  The justification for the RFC-breaking connection
>> drop is IIRC that it's merely propagating the same from the backend
>> to the client.  That doesn't apply in the case of a timeout.
>>
>
> Yes, I came to the same conclusion in the meantime. The firewall drop can be
> prevented by setting keepalive to on. Furthermore the typical keepalive
> timeouts
> for http connections are way below the typical firewall timeouts. So if we
> get back APR_TIMEUP we can safely assume that the backend did not respond in
> a timely manner. Looking at his patch I think it looks basically fine.
> Hope to find some time for a closer look and a commit later on.
>
> Regards
>
> RĂ¼diger
>

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