>From "Squid - the definitive guide", a simplified description of the refresh_pattern algorithm is: - The response is stale if the response age is greater than the refresh_pattern max value. - The response is fresh if the LM-factor is less than the refresh_pattern percent value. - The response is fresh if the response age is less than the refresh_pattern min value. - Otherwise, the response is stale. The webserver I have neither sends a Last-modified header nor an Expires header. > >From squid.conf, > > refresh_pattern . 21600 100% 21600 override-expire > > > > That is, a cached page is fresh if its age in cache < 15 days > > (21600=15*24*60). > > > not quite, an object without an explicit expiry time, but that can be > validated, could be stale in less than 15 days. > So, won't all pages with response age < 15 be considered fresh? On Wed, 2009-12-23 at 16:10 -0800, RW wrote: > On Wed, 23 Dec 2009 15:10:34 -0800 > Manjusha Maddala <mmaddala25@xxxxxxxxxx> wrote: > > > Hi, > > > > >From squid.conf, > > refresh_pattern . 21600 100% 21600 override-expire > > > > That is, a cached page is fresh if its age in cache < 15 days > > (21600=15*24*60). > > not quite, an object without an explicit expiry time, but that can be > validated, could be stale in less than 15 days. > > see override-lastmod > > > I noticed that sending HTTP requests to pages older than 30 days > > result in TCP_REFRESH_MISS while requests for pages cached in the > > last 30 days either result in TCP_HIT or TCP_MISS. Since the min time > > for refresh_pattern is 15days, shouldn't it be like pages older than > > 15days should be validated against the parent > > (REFRESH_MISS/REFRESH_HIT) while all other pages are either TCP_HIT > > or TCP_MISS. How did the limit change from 15 to 30? Has anybody else > > seen such an anamoly? > > It's not an anomally - from the sample squid.conf file: > > override-expire enforces min age even if the server > sent an explicit expiry time > ... > Note: this does not enforce staleness - it only extends > freshness / min. If the server returns a Expires time which > is longer than your max time, Squid will still consider > the object fresh for that period of time. > > > > Also, if there's no refresh_pattern matching a URI, how would Squid > > process that HTTP request? Would it get a fresh copy from the parent > > or will it return the cached copy? > > Presumably the heuristic algorithm for freshness would be disabled > and anything without an explicit expiry time would be stale. It's not > really a sensible thing to do though. > > > > > > CONFIDENTIALITY NOTICE > > ======================= > > This email message and any attachments are for the exclusive use of > > the intended recipient(s) and may contain confidential and privileged > > information. Any unauthorized review, use, disclosure or > > distribution is prohibited. If you are not the intended recipient, > > please contact the sender by reply email and destroy all copies of > > the original message along with any attachments, from your computer > > system. If you are the intended recipient, please be advised that > > the content of this message is subject to access, review and > > disclosure by the sender's Email System Administrator. > > >
