[drupal-devel] caching issues
steven at acko.net
Wed Mar 9 04:16:27 UTC 2005
>Thoughts? Feedback? Suggestions? Dries?
Dries and I did a bunch of cache tests a while ago, the conclusions were
posted on the list. I think it was shortly after the 4.5 release.
Various ideas for keeping the cache alive longer were posted as well.
Ones I can remember:
- Enforcing a minimum cache lifetime for pages is pretty easy with the
timestamp/expiration parameter for cache.
- It is important that a user sees his/her changes reflected
immediately, otherwise they might think an error occured and post twice.
Possible solution: disable caching for a user's session as soon as a
they have posted something. For your case this would mean the spambot
get fresh pages all the time, but the rest doesn't.
- Clearing the cache selectively is difficult because sidebar blocks
like "active forum topics" change easily. Still, clearing out the "main"
page for a certain item (e.g. a node view) is doable.
- The cache has a much higher miss rate than expected on drupal.org at
least because the site is constantly being crawled by spiders. Pages
that are visited often get re-cached quickly after a wipe, but this
doesn't happen for the random access pattern that is common for spiders
and also for posts reached through searching.
- Any aggressive caching should be implemented as an optional feature as
it is useless for small sites. Perhaps we could change the cache option
into three states: "No caching" "Mild caching" "Aggressive caching".
Still, it sounds to me like your problem could be fixed by imposing a
throttle on submissions (we used to have this, but it got lost in one of
the node system rewrites) or by trying to detect spammy behaviour and
imposing a (temporary) ban.
If you dig around the mailinglist archive some more, you might find some
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