Re: possible squid bugs [was: cacheability engine]

From: Henrik Nordstrom <hno@dont-contact.us>
Date: Tue, 28 Mar 2000 00:54:31 +0200

Duane Wessels wrote:

> I played around with the 2.4 code and removed 'expires' from StoreEntry
> and replaced 'lastmod' with 'lastvalid'. This makes the StoreEntry
> smaller, but also makes it incompatible with current caches. Anyway,
> it seems to work okay. I think we can stop storing lastmodified
> time in StoreEntry and store lastvalid time instead.

What about my earlier proposal to change the storeentry to only contain
last-validated and fresh-until timestamps, and get rid of all other
timestamps (including last-modified).

last-validated is used for Age and Date headers. It is the date header
from the last response seen for the object, or time the request was sent
if no date header is present (or invalid date header).

fresh-until is the result of the refresh check, and recalculated on
cache hits.

This makes the timestamps non-ambigous, solves the issue where Squid is
giving overly stale Date headers, uses less memory and fixes the refresh
issue with cache digests.

Unless you change the freshness calculation to be on storage/refresh you
must store lastmodified to be able to calculate the refresh pattern on
ICP requests.

/Henrik
Received on Mon Mar 27 2000 - 16:14:26 MST

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