What
about memcached?
(that would be a key based on the original db name)
The storage has to be persistent to accommodate wiki crashes (e.g.,
httpd crash, server OS crash, power outage). It might be possible to
use memcachedb, but as far as I am aware that requires installing
Berkeley DB, which complicated deployment.
Why not employ the already installed DB software used by the wiki? That
provides persistent storage and requires no additional software.
My original idea was to use whatever ObjectCache the wiki used, but it
could be forced to use the db as backend (that's the objectcache table).