Re: [squid-users] TCP_REFRESH_HIT

From: tookers <gareth_at_garethcoffey.com>
Date: Wed, 14 Oct 2009 08:29:19 -0700 (PDT)

bergenpeak_at_comcast.net wrote:
>
> Is there a way to look at the object cache in squid and determine the
> current "freshness" of the content?
>
> I've got content in the squid cache where I would expect the content to
> be a "TCP_HIT". Looking in the squid access.log, I see the access to
> the object being reported as "TCP_REFRESH_HIT". I'm trying to
> understand if it's something in the client request or something in how
> the original object was served up by the origin server which is causing
> squid to re-verify with the origin server that the object hasn't changed.
>
> Thanks
>
>
>
>

Hi there,

The Squid docs state that TCP_REFRESH_HIT is when an object is in cache but
is STALE, the IMS (if-modified-since) query results in a '304 - not
modified'. So the object is cached but has reached the max-age (e.g. 60
secs), Squid then checks on the back-end to see if a fresh version of the
file exists. It comes back with status 304 because the object in cache, and
on the back-end, are the same. If you are seeing lots of TCP_REFRESH_HIT,
and the file isn't updated very often, it may be worthwhile increasing the
cache time.

HTH.

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Received on Wed Oct 14 2009 - 15:29:22 MDT

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