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From Graham Leggett <>
Subject Re: proxy caching is important
Date Thu, 18 Nov 1999 13:55:36 GMT
Ryan Bloom wrote:

> Okay, I gave my APR opinion, now for my Apache opinion.  (I love changing
> hats  :-)


> I don't see a good way to do this without I/O layering, or without being
> able to determine which modules are loaded in the server.  I/O layering
> isn't coming until 2.1 at the earliest.  That is an upsetting but true
> fact.  It is just going to take too long to put it into 2.0, and we'll
> never release a beta.

This is why I would build the hashing functions into either APR or if
not appropriate the Apache core.

The putting-objects-into-cache function would then be built in to the
other modules where needed and practical, knowing that without IO
layering the full solution isn't here yet. For example the module
responsible for shipping static content should be the first place to
build the cache into, what gets pumped to the browser also gets pumped
to the cache. These modules will be using the hash table functions
implemented either in APR or the core, but not in mod_cache (even though
it would be nice if it was).

The pulling-cached-objects-out-and-serving-them job will be done by a
piece of code called mod_cache. It's job is to decide if it's
appropriate to serve cached data (Pragma: no-cache stopping me
perhaps?), then to determine if there is cached data (no there isn't,
I'll get over it) and last of all to ship the data to the client if all
is well.

I get your point about the hashing function, so the underlying "common
code" will be a general hash table accesible to all of Apache-land
either via APR or via the Apache core, whichever. Putting stuff into the
cache will be a function of those areas of the code that have been
modified to support it. To start with simple bits like the serving of
static content only, with more complex bits down the line. Finally the
last third of the job will be handling by mod_cache as described above.
mod_cache would be only 33% of the solution, not 100%.

-----------------------------------------		"There's a moon
					over Bourbon Street

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