[support] how cache works: on the fly content creation (not node) and caching

[Ivan Sergio Borgonovo]

Hi,

I've a lot of content that get created automatically on-the-fly from
a DB.

Mapping this content to nodes is not practical (custom search, just
a minority of the content get actually displayed etc...).

I need a means to check if the cache is still valid at *request*
time. I can't know when the cache *will* expire at request time but
I know if it is already expired.

Considering that the pk for page cache is the url and that a
minority of the pages will actually be cached periodically
invalidating all the urls checking if the underlying DB record is
younger is highly inefficient.

Before just building my cache tables and build up my own cache
system on top of cache API, is there an alternative approach?

-- 
Ivan Sergio Borgonovo
http://www.webthatworks.it