Re: squid 2.2 STABLE1 and TCP_MISS rate

From: David J Woolley <>
Date: Fri, 23 Apr 1999 16:46:08 +0100

> >From the refresh speed, I suspect I'm getting a cache hit when I do a
> 'refresh' from Netscape, even if it is recorded as TCP_MISS/304. It sure
> seems like the refresh is too fast to be going back to the server. Is this

Unfortunately one can get a conflict between a browser cache and a
public cache if the public cache doesn't contain the page but the
browser cache does. What then happens is that the browser does and
if-modified-since request, which misses on the public cache, but only
produces a short response from an upstream cache or the origin server.

Squid cannot currently cache this. It has been said that there is
enough information to permit it to be cached, but that was before
there was a change in the handling of the length field for 304
responses, so I'm not sure that it is still possible.

Ideally, you should get private caches purged frequently if you don't
want If-Modified-Since request to get pushed upstream every time for
popular pages.

It can be worth force loading pages that have recently generated
TCP_MISS/304, so that they are in the cache.

David Woolley - Office: David Woolley <>
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Received on Fri Apr 23 1999 - 10:09:09 MDT

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