Re: WGLC: p1 MUST NOT pipeline until connection is persistent

Willy Tarreau <w@1wt.eu> Wed, 01 May 2013 08:18 UTC

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Date: Wed, 1 May 2013 10:16:53 +0200
From: Willy Tarreau <w@1wt.eu>
To: Alex Rousskov <rousskov@measurement-factory.com>
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Subject: Re: WGLC: p1 MUST NOT pipeline until connection is persistent
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On Wed, May 01, 2013 at 01:51:01AM -0600, Alex Rousskov wrote:
> On 05/01/2013 01:40 AM, Willy Tarreau wrote:
> > On Wed, May 01, 2013 at 01:34:12AM -0600, Alex Rousskov wrote:
> 
> >> I am still not sure why we are prohibiting retry pipelining on new
> >> connections though. Why do we have to reuse an old connection if we want
> >> to retry a failed pipeline?
> 
> > I don't remember, I believe it was just that if pipeline failed on a
> > connection, you don't want to pipeline again on the new one, otherwise
> > you can do that infinitely.
> 
> And if I use an old connection, the situation is guaranteed to be better
> somehow?
> 
> The reasons a new connection may fail differ from the reasons an old
> connection may fail, but both may fail, so I do not understand why we
> are prohibiting one and requiring the other.

No it's not that, it's that if you detect a failure on a connection where
you pipelined, you should not attempt to pipeline again on the new connection
since it will very likely end the same way. It's unrelated to the old
connection being better at all.

Willy