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Re: accelerating apache/QSC. (fwd)

To: tcl@xxxxxxxxx (tc lewis)
Subject: Re: accelerating apache/QSC. (fwd)
From: mja@xxxxxxxxxxxxxxxxxxx (Mike Abbott)
Date: Wed, 16 Aug 2000 17:06:10 -0700 (PDT)
Cc: apache@xxxxxxxxxxx
In-reply-to: <Pine.LNX.4.10.10008071916080.31092-100000@magician.bunzy.net> from "tc lewis" at Aug 07, 2000 07:17:18 PM
Sender: owner-apache@xxxxxxxxxxx
I'm back from vacation.  Are you able to use the QSC now or may I still
help?

> is there a document
> anywhere that documents what changes sgi has made in the patches as an
> overview, or should i continue reading through the actual patch?

There's some documentation about some important functional parts of the
patches:
        http://oss.sgi.com/projects/apache/patchinfo.html#documentation
which unfortunately looks right only when viewed as part of the Apache
server documentation (in other words it would look bad standalone on
oss.sgi.com).  I won't write docs this way again; in the future all the
docs will work both ways.

There is no overview document, although I have been sitting on an
unfinished one for a year.  You can craft your own history and overview
by chasing links from
        http://oss.sgi.com/projects/apache/news.html
and/or reading each version's patchinfo page and seeing how things
progress over time:
        http://oss.sgi.com/projects/apache/patchinfo-1.3.6.html
        http://oss.sgi.com/projects/apache/patchinfo-1.3.9.html
etc.

> also, i have a question about QSC.  i have it compiled in, and it's
> enabled, but for some reason every page appears to be "uncachable".

The other responders were correct.  The QSC is tightly integrated with
the mmap_static module.  The QSC responds only to pages that are
mmapfile'd.  See the #using and #primer sections of
htdocs/manual/qsc.html in your patched source tree.

> the -D__i686__ is because gcc only seems to define __i386__, yet
> src/main/qsc.c checks for 486, 586, 686, or pentiumpro.

See http://oss.sgi.com/projects/apache/faq.html#Q17

> i've seen the mmapfile directive with mmap_static, but i was under the
> assumption that QSC handles caching much more automatically and
> dynamically.

The QSC caches only responses generated by mmap_static which requires an
explicit list of files to map.  Yes this is a clunky interface, but you
don't have to mmapfile every file, just the popular ones will do.  You
don't need to use the find command every time the server starts:  mine
the logs for the most-requested static files and map just those.  Adjust
the list occasionally as part of routine maintenance.

> if not, what are its benefits?

Its benefit is about 30% faster response.

> qsc must have features beyond mmap_static.

The QSC exists only to make Apache serve HTTP GET requests for static
content faster.  For a more dynamic, self-balancing, easier to
configure, reputedly buggy, and much slower cache try mod_cache in
apache-contrib-1.0.8 from http://www.apache.org/dist/contrib/modules/1.3/ .

Please let me know if you have any other questions.
-- 
Michael J. Abbott        mja@xxxxxxx        http://reality.sgi.com/mja/

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