Thanks. Right now I have the squid content "ttl" set to 3600. However,
I think either the client is sending a "Cache control max-age=X" (where
X is < 3600) or where the origin server is providing the object to squid
with some cache control or equiv attributes to some value << 3600 which
is forcing squid to reverify the content hasn't changed. I'm trying to
determine if the issue is a client setting or origin server setting
which is (apprently) overriding the squid setting. Wondering what
knobs/tools exist within squid to see information about whether the
object is "fresh" or "stale".
Thanks
tookers wrote:
bergenpeak@xxxxxxxxxxx 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.
