Re: [squid-users] Caching Expired Objects

Hi Henrik,
thanks for your insightful response. However, the
object is a .flv file that hasn't changed in months.
The origin server certainly doesn't want the object
cached, but I want to. Any leads that can help me
achieve this?

Regards,
solomon.

--- Henrik Nordstrom <henrik@henriknordstrom.net>
wrote:

> On mån, 2007-09-17 at 11:55 -0700, Solomon Asare
> wrote:
> > Hi Amos,
> > I am not sure if refresh_pattern is the sole
> > determinant in caching an object, that is if it
> has
> > any influence at all.
>
> It has influence, both directly by assigning
> freshness information when
> there is none, and indirectly by overriding various
> HTTP controls..
>
> Requirementsto cache stale objects:
>
> a) The object must have a cache validator
> (Last-Modified or ETag). If
> there is no cache validator then the response must
> be fresh for at least
> minimum_expiry_time to get cached, this to avoid
> wasting disk I/O for
> caching content which can not be reused.
>
> b) There must not be other headers preventing it
> from getting cached.
> refresh_pattern can override most of these if
> needed.
>
> > I am not discussing getting a
> > HIT for a cached object, but rather caching an
> expired
> > object from an origin server. If this object is
> > expired, by say 60 seconds before being served
> from
> > the origin server, how do I cache it? Date and
> > Last-Modified dates are also not set.
>
> If there is no Last-Modified and no ETag then it's
> useless to cache an
> expired object, as it can not be reused on any
> future request and all
> you get is extra disk I/O for writing the object
> out.
>
> A cache validator (Last-Modified or ETag) is
> required to be able to
> verify with the origin server if an expired object
> is still valid or
> not. Without a cache validator there is nothing to
> relate to and there
> is no other choice than to fetch the complete object
> again when
> expired..
>
> Regards
> Henrik
>
Received on Tue Sep 18 2007 - 02:41:29 MDT