howard chen wrote:
Hi Folks,
From the wikipedia' system diagram, seems that Squid play an important role in the system architecture.
But how does Squid handle user customized page?
E.g. A page containing user logon name or IP ect. at the top of the page?
I think squid can't handle this, right (Unless you are using squid 3 ESI)?
Squids handle anonymous requests. Mediawiki can show the IP on the top of the page, but it's disabled on wikimedia sites precisely to have it cacheable.
They are obviously not cached at squid level for logged in users (but things like rendered html are cached for everyone at memcache) although they do serve the images for everyone.
Finally, an interesting point on wikimedia squid caching is that the pages aren't cached by time, as there's no way to know how much time will elapse before next edit, but they are cached sine die and then purged when there's an edit (or purge, or a template is changed...) Squids at tampa get purged with a udp multicast notice, which is routed via tcp to the other squid clusters, where they are converted again to udp multicast.