Re: cache statistics

[Fred Douglis <douglis@research.att.com>]

>I took a look at an ISPs forward proxy cache stats from about 300GB of data an
>d have found the following:
>
...
>A breakdown of the non cacheable stats shows:
...
>Cookie in Response: 3.3%
...


This is a hot button of mine, because I have seen this sort of 
breakdown on numerous occasions.  Am I mistaken, or is a cookie
in the *request* also *possibly* a reason why data might be 
uncachable in HTTP/1.0, while for 1.1, explicit cache headers
are to be used and the presence of a cookie is deemed irrelevant?

How did your data break down 1.0 v 1.1, and how many requests had
cookies?  I say that the request is sufficient because a request that
identifies a user can get a user-specific response even if the
reply doesn't include a cookie.  However, I know there are many
cases where caches choose to ignore that fact, and I recall hearing
that some analysis showed that most content (at least images) will
be the same regardless of the cookie.

Fred