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From Marc Slemko <ma...@worldgate.com>
Subject Re: Redirect to negotiated docs (PR#649)
Date Fri, 15 Aug 1997 22:49:30 GMT
No.  Because of the redirect.  Most hits won't be cached.  That means that
if you write HTML like Ken (<g>) you will do:

	<A HREF="docs/misc/FAQ">wheee</A>

You are using multiviews.  That is "content negotiation", in one manner of
speaking.  However, for multiviews it isn't really based on client
capabilities so there normally isn't any wrong varient to cache.  If you
send a redirect to FAQ.html, the client (assuming nothing cached) will
have to send another request. 

If they don't do persistent connections, that is _really_ expensive.  If
they do, you still have an extra 2*RTT in there; with dialup users, that
can easily amount to a second.  If you do this for all your images as
well, it hurts.

Content negotiation based on things like languages is a slightly different
matter, but you still do have a large performance hit on links with a high
rtt.

On Fri, 15 Aug 1997, Paul Sutton wrote:

> On Fri, 15 Aug 1997, Marc Slemko wrote:
> > On Fri, 15 Aug 1997, Paul Sutton wrote:
> > > agree with CacheNegotiatedDocs so I would say not. But it is hard to
> > > reject the patch with "no because caching negotiated resources is bad
> > > pre-1.1" since the submitter can point to CacheNegotiatedDocs and say "so
> > > why does Apache allow it then?". Which I can't answer. Why does it?
> > 
> > Assuming you include multiviews, this would destroy sites using them,
> > especially with clients that don't do persistent connections.  Even if
> > they do, it is a 2*RTT increase in time per file.
> 
> You mean because the client cannot cache the response? But surely that is
> better than the client (or worse, a proxy) caching the *wrong* variant?
> I'll be really glad when mot browsers are fully HTTP/1.1 compliant so we
> can forget about this. 
> 
> //pcs
> 
> 


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