[squid-users] caching and changing content

Alex Rousskov rousskov at measurement-factory.com
Thu Sep 12 17:14:01 UTC 2019

On 9/12/19 12:22 PM, fansari wrote:
> '--enable-delay-pools'

OK, so we should be careful with not trusting TCP_MISS too much.

> http://squid-web-proxy-cache.1019090.n4.nabble.com/file/t377780/cache.log

Squid shows these headers for the second response (near 15:40:03.814):

> X-Cache: MISS from my-client-02
> X-Cache-Lookup: HIT from my-client-02:3128

This means that Squid found the requested resource in the cache (good!)
but decided not to use that cached response (bad).

Moreover, according to your cache.log, Squid decided not to send a
conditional request to check that cached response freshness. Squid sent
a regular/unconditional request instead. I do not know why. Perhaps your
old Squid does not support revalidation using weak E-Tags, but that is
just a wild guess.

If others cannot find the answer in your logs, then one way to figure it
out would be to increase debugging (debug_options ALL,3 88,7 22,7). An
alternative strategy would be to upgrade to Squid v4 in hope that it
would be better at revalidating this particular resource.



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