Thanks for the useful explanation Henrik! Cheers, Chris Christian Tzolov | Senior Software Developer - Content & Services | TomTom | christian.tzolov@xxxxxxxxxx | +31 (0)207575451 | Oosterdoksstraat 114, 1011 DK, Amsterdam > -----Original Message----- > From: Henrik Nordstrom [mailto:henrik@xxxxxxxxxxxxxxxxxxx] > Sent: Thursday, October 02, 2008 12:52 PM > To: Christian Tzolov > Cc: Amos Jeffries; squid-users@xxxxxxxxxxxxxxx > Subject: RE: Can we use "no-cache" or "max-age=0" to refresh > the cached objects > > On tor, 2008-10-02 at 10:57 +0200, Christian Tzolov wrote: > > > I am scared by the "I believe" part :). > > > > 1. Can we relay on Squid to always update its cached content if the > > response is newer (e.g. response has new Expires date and no other > > validators)? > > Yes. > > > 2. Squid does not change/optimize its behavior under high load in way > > that could affect assumption (1)? > > Under very high load you may in worst case end up with no on-disk copy > of the cached object if an overload condition does not allow writing > objects out to disk.. > > > 3. If (1) holds is this a (HTTP) standard behavior or Squid > > implementation? > > Yes. Or to be exact the standard requires the old copy to be invalidated > if different from the new. There is no requirement to cache the new > representation. > > Note however that there is a significant difference between no-cache and > max-age=0: > > * no-cache forces a new retreival, The response is not allowed to be > satisfied from cache. > > * max-age=0 forces a cache validation and allows the old version to be > returned if the server says it's still fresh. > > Regards > Henrik
