[pmwiki-users] category analysis RFV

Patrick R. Michaud pmichaud at pobox.com
Wed Mar 16 15:12:45 CST 2005


On Wed, Mar 16, 2005 at 11:45:37AM -0500, Radu wrote:
> 
> Can't we make at least categories hard-coded? See
> http://www.pmwiki.org/wiki/PITS/00392
> 
> Of course, I might have missed something again :)

The hardest part of any caching system is knowing when to 
invalidate the cache.  

It's almost certain that PITS:00392, as written, will confuse
a lot of people, because placing a page in a category doesn't
cause the category page to be updated until someone does 
?action=refresh on the category page.  Or the net result is that
readers will just be used to always hitting ?action=refresh
in case nobody else has done it previously, in which case they
get the cost of generating the page PLUS having to hit the extra link.

And knowing to re-generate the page when someone has removed it from
a category is even tougher (yes, there are ways to address this).

There are worse effects, because the rendering into the cache will
depend on whatever authorizations are in effect at the time the rendering
is done, but later viewers (who may have different authorizations) may
then see results they're not authorized to see or miss results they
are authorized to see.

I'm just of the opinion that caching isn't the way to go for dynamic
results such as these -- a much better, more robust, and overall
faster solution is to build a cross-reference index and use that
to generate pagelists.  Searches will still be slow, but searches
of specific sets of pages (groups, trails, categories) will be relatively
quick and PmWiki really isn't a search engine.

Pm



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