On Wed, 25 Feb 2004, Gerard Fremaint wrote:

> I don't understand very well what does the percent option in the
> refresh_pattern mean , can someone explain it to me ?
> Also how can I know the expiration date of an object being cached, and how
> does the expiration date for an object cached is set ?

The expiration date is set by either

a) Explicit expiry date set by origin server

b) refresh_pattern if no explicit expiry date provided.

The refresh_pattern simply defines the expiry date as a function of how
long ago the object was last modified, with a max/min value to keep it

So with the default refresh_pattern an object last modified 1 week ago
will be considered fresh by Squid for 33 1/2 hours (20% of 1 week).