Re: [squid-users] Multiple simultaneous requests

On Mon, 29 Jun 2009 17:33:35 -0700 (PDT), Judson <nyarly_at_gmail.com> wrote:
> I'm working with an application that generates a sort of strange traffic
> pattern, which is really hurting our cache rate. Basically, all of our
> users request a specific URL at the same time. As a result, we get many
> many misses as subsequent requests are coming in before the proxy request
> has returned to populate the cache.
>
> In other words:
> Browser A makes a request for /resource_x?v=1. This is the first request
> for this resource, so it's a MISS, and Squid goes on to request the
> resource
> from our app server.
>
> Browser B makes a request for /resource_x?v=1. Even though A is still
> waiting for the response to its request, this is still a MISS, so Squid
> makes a second request for the same resource.
>
> (and so on, until...)
>
> The first response to Squid's request for /resource_x?v=1 comes back,
Squid
> returns its response to (probably) browser A, and subsequent requests get
> HITs.
>
>
> My question is: is there a way to configure Squid such that it recognizes
> that it's currently waiting on a specific resource, and block subsequent
> requests until the response it makes comes back? In other words, all the
> B's still count as MISSES, but Squid only makes *one* request back to the
> app server?

There is. Collapsed Forwarding was developed for precisely this situation.
Note that it is currently only available in Squid-2 releases.
http://www.squid-cache.org/Doc/config/collapsed_forwarding/

Amos
Received on Tue Jun 30 2009 - 01:49:22 MDT