Philipp Albig wrote:
That works for all the cache. Maybe it's too easy - but how or where is the cache for a article cleared, for example after editing? Sorry, I didn't find sth. about that.
When a page is updated directly or indirectly, the timestamp in the page_touched field (cur_touched on <= 1.4) is updated to the current time. Cached are checked against this timestamp at load time and discarded if the page_touched time is newer, forcing a re-rendering.
There is also a per-user timestamp which is updated when you log in, log out, change preferences, watch/unwatch some page, etc. If the user_touched timestamp is newer than the HTTP If-Modified-Since header, the page will be re-output (but the parser cache may still be used).
Additionally, with squid proxy mode on a PURGE request is sent to the proxy when page_touched is updated. This allows the squids to avoid hitting the apache servers to do cache validity checks for the majority of anonymous page view hits.
-- brion vibber (brion @ pobox.com)