Re: [squid-users] removing objects from memory cache?

From: Henrik Nordström <hno@dont-contact.us>
Date: Thu, 5 Sep 2002 22:46:43 +0200 (CEST)

On Thu, 5 Sep 2002, Ricardo Kustner wrote:

> So my guess is that it could be that the process of cleaning a whole
> site with hundreds of pages from the cache (using
> http://www.cache.dfn.de/DFN-Cache/Development/Purge/, which finds the
> objects in the file cache and constructs the PURGE requests)
> sends a lot of PURGE requests in a short time; meanwhile the websites
> are still being accessed by clients so maybe something goes wrong,
> causing some of the PURGE request to get lost?

Maybe.. as I said, see your access.log.

> I'm just guessing here... it's kinda weird and hard to reproduce.
> It turns out that a Mozilla-reload *always* makes squid serve a fresh
> document (no need for a PURGE) so that seems to be unrelated.

Mozilla sends a "Cache-Control: max-age=0" on reload, which forces Squid
to bypass the cache.

Most other browsers send a "Pragma: no-cache", which can be overridden by
refresh_pattern by the "ignore-reload" option, and I seem to recall you
are using this option.

Some (most?) versions of IE does not send a "Pragma: no-cache" or any
other "please do not give me a cached copy" header unless configured to
use a proxy... which btw is a valid thing to do, if it wasn't for
surrogate servers/accelerators or the black art of "transparent
interception" proxying that messes up the assumed
user-agent<->originserver relations.

Regards
Henrik
Received on Thu Sep 05 2002 - 14:46:45 MDT

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