After some further investigation, it seem that RELEASE does not mean that Squid deletes the object from cache. It appears that it releases from cache to the request.
To restate the problem I am having:
Squid seems to re-fetch the entire object even though the object never changed on the server after about 1 day - 2 days.
Here's my test scenario:
Object is initially cached. Max age in squid.conf is set to 1 min. Before 1 min passes, I request the object and Squid returns TCP_HIT. After 1 min, I try to request for object again. Squid returns TCP_REFRESH_HIT, which is what I expect. I leave the entire system untouched. A day or a day and a half later, I ask for the object again and Squid returns TCP_REFRESH_MISS/200.
What could possibly cause Squid to refetch the entire object again?
Could there possibly be a problem with the interaction between IE7 and Squid that is forcing Squid to re-fetch the entire object?
Anyone with ideas on why this behavior occurs?
Thanks
----- Original Message ----
From: BUI18 <lbui18@xxxxxxxxx>
To: Henrik Nordstrom <henrik@xxxxxxxxxxxxxxxxxxx>
Cc: squid-users@xxxxxxxxxxxxxxx
Sent: Tuesday, October 21, 2008 8:25:14 AM
Subject: Re: Objects Release from Cache Earlier Than Expected
The web server is IIS 6.
1) Would there be any reason why it would return the full object when in fact the object has not been modified?
2) If the min age guarantees freshness of the object, why would Squid actually issue and IMS request to the web server in the first place? As I understand it, Squid should only issue and IMS request when objects become STALE. As such, I would have expected Squid to return TCP_HIT instead of TCP_REFRESH_MISS.
3) My big concern is that the store.log shows that the object was released (deleted) from cache well before the min age while there is still and abundant amount of disk space is available.
Also, one other question:
When Squid issues and IMS request, which date does it use? Is it the date/time that it retrieved the object or is it the Last Modified date/time of the object ascertained by Squid on first retrieval of the object?
Regards
-bui
----- Original Message ----
From: Henrik Nordstrom <henrik@xxxxxxxxxxxxxxxxxxx>
To: BUI18 <lbui18@xxxxxxxxx>
Cc: squid-users@xxxxxxxxxxxxxxx
Sent: Tuesday, October 21, 2008 3:50:20 AM
Subject: Re: Objects Release from Cache Earlier Than Expected
On mån, 2008-10-20 at 17:45 -0700, BUI18 wrote:
> I not sure what you mean by a newer copy of the same URL? Can you elaborate on that a bit?
The cache (i.e. Squid) performed a conditional request to the origin web
server, and the web server returned a new 200 OK object with full
content instead of a small 304 Not Modified.
Regards
Henrik
