Are you logged in to the wiki? Squid will always bypass its cache for page requests from logged-in users.
I has tried to login and logout, but nothing changed. I beleive cache miss becomes because of response headers
Cache-Control |no-cache, no-store, max-age=0, must-revalidate
but not sure. I would force squid to ignore this headers, but this is not right because there is special pages, which are absolutely dynamic and must not be cached.
And without caching my web server just dies on the load. |