RE: [squid-users] Persistent Connections to Parent Proxy

----------------------------------------
> Date: Fri, 29 Apr 2011 01:12:55 +1200
> From: squid3_at_treenet.co.nz
> To: squid-users_at_squid-cache.org
> Subject: Re: [squid-users] Persistent Connections to Parent Proxy
>
> On 28/04/11 20:19, Mathias Fischer wrote:
> > Hi,
> >
> > We use squid together with a content scanner connected as parent proxy
> > (cache_peer parent) with none of them caching any content. When
> > upgrading from squid 2.7 to 3.1, we observed an increased number of TCP
> > connections between squid and its parent. I analysed the traffic between
> > squid and the parent proxy (for both squid versions), and found (among
> > some differences in HTTP version and (Proxy-)Connection header) that the
>
> Proxy-Connection: has never been a registered header suitable for
> transmission. Squid-3 was mistakenly made to send it for a while instead
> of just accept it. That bug has been fixed in recent releases.
> Only Connection: shod be sent over the wire.
>
> > usage of persistent connections has changed. In squid 2.7, a persistent
> > connection to the parent proxy is shared for multiple origin servers,
> > while in squid 3.1, there is at least one connection per origin server.
> > Obviously, this results in a much higher total number of connections.
>
> Hmm, I thought we corrected that the same way in both 3.1 and 2.7.
> 3.0 and 2.6 certainly had that behaviour.
>
> Current 2.7 and 3.1 should have (peer_IP, domain_name) as the pconn key.
> There can be multiple duplicates of course up to as many as needed to
> handle peak load (moderated by how fast the peer closes them).
>
> >
> > Is there a possibility to influence this behaviour? To me, it looks like
> > this is related to the introduced Connection Pinning [1] feature.
>
> Pinning links one server FD per client connection, kind of an
> independent and special type of persistence. It should not be showing
> this behaviour, though yes it also will cause a multitude of server
> connections.
>
> >
> > As a workaround, I see the option to reduce the number of open
> > persistent connections through pconn_timeout, but this will have an
> > impact on other connections as well which could reduce performance.
>
> We have a re-structuring if the conn and pconn handling coming to 3.2
> shortly (a few weeks) which removes the domain name from the pconn key.
 
We have the same problem in 3.2.0.1 and 3.2.0.7
 
Is this planned for 3.2.0.8?
 
Thanks!
 
Jenny
                                                
Received on Thu Apr 28 2011 - 19:29:03 MDT