On Mon, May 21, 2007 4:49 pm, Niklas Edmundsson wrote:
> Does anybody see a problem with changing mod_cache to
not update the
> stored headers when the request has max-age=0, the body
turns out
> not to be stale and the on-disk header hasn't expired?
>
> The rationale behind this is that there are hordes of
stupid "download
> managers" that always issue this kind of request,
and multiple in
> parallell to the same file at that. This hammers the
entire
> cache-layer by causing headers to be rewritten for each
request.
>
> Since max-age=0 requests can't be fulfilled without
revalidating the
> object they don't benefit from this header rewrite, and
requests with
> max-age!=0 that can benefit from the header rewrite
won't be affected
> by this change.
>
> Am I making sense? Have I missed something
fundamental?
At first glance, doing this I think will break RFC2616
compliance, and if
it does break RFC compliance then I think it should not be
default
behaviour. However if it does solve a real problem for
admins, then having
a directive allowing the admin to enable this behaviour does
make sense.
Zooming out a little bit, this seems to fall into the
category of "RFC
violations that allow the cache to either hit the backend
less, or hit the
backend not at all, for the benefit of an admin who knows
whet they are
doing".
A simple set of directives that allow an admin to break RFC
compliance
under certain circumstances in order to achieve certain
goals does make
sense.
Regards,
Graham
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