result caching (was Re: [Zope] 450 hits/s with 40+ TPS ...)

[Jamie Heilman]

Ben Last (Zope) wrote:
> Anyway, one reason I'm responding here is that I've been comparing effects
> of RamCache with use of AcceleratedHTTPCache to manage an Apache 2 cache.  I
> pretty much get equivalent results, with Apache caching *slightly* faster.
> Appears that either Zope uses RAM to cache stuff, or Linux uses it to cache
> the disk or file page cache that Apache uses.  Anyone else done this sort of
> testing?

The Zope result caching tools have a time and a place when they should
be used, and several where they should not.  The Accelerated HTTP
Cache Management stuff doesn't belong in the same league as the RAM
Cache Manager; the former is protocol and header control, the latter
is physical cache of keys and values.  Using a cache in your gateway
server is different again, its only for caching entire resources.

Its really important to understand the distinctions if you expect to
get anything from caching.

For example, using a RAM Cache Manager to accelerate the render times
of static content is a waste of resources, using a RAM Cache Manager
to accelerate times of dynamic content about to published is a waste
of resourcs, and quite possibly dangerous from a security standpoint.
Using a RAM Cache Manager to accelerate the rendering of intermediate
objects that are not published directly and who's dynamic arguments
have already been declared safe, is an appropriate use.

In general, content that is about to be published should be cached by
the gateway server, or by the Acclerated HTTP Cache Manager in the
event that the gateway server doesn't have enough context to do a good
job.


-- 
Jamie Heilman                     http://audible.transient.net/~jamie/
"...thats the metaphorical equivalent of flopping your wedding tackle
 into a lion's mouth and flicking his lovespuds with a wet towel, pure
 insanity..."                                           -Rimmer