Re: mod_cache responsibilities vs mod_xxx_cache provider responsibilities

[Graham Leggett <mi...@sharp.fm>]

On Thu, September 14, 2006 2:07 pm, Davi Arnaut wrote:

> The cache is required to send to the client the most up-to-date
> response, it doesn't mean it must cache it.

As I recall once cached, if an entry is stale and is revalidated, the
headers coming back with the 304 Not Modified must replace the headers in
the cache.

> What I meant is _if_ it causes significant slowdowns for a common
> cache hit path _probably_ it is better to just revalidate the hole
> entity.

The point behind the cache is that the cache is cheap, while the backend
is expensive. A cache slowdown usually isn't critical, as the cache is
usually significantly faster than the backend. Trying to save a few cycles
in the cache by hitting the backend unnecessarily gives you little
performance gain.

Regards,
Graham
--