Your help and support is appreciated! I think my replies come across as that I don't want to implement memcached caching. I do want to give it a try.

But to give it a try, I have to install, secure and set up memcached, and look for a spot where I can use it easily within PM, so it's just not instantaneous.

my help also included this skeleton script for KinoSearch, for which I never got any comment.
also i would look into the logs to first look where an optimization is *needed*.
what i learned about optimization is:
first look by analysing real world requests where the bottleneck is. (easy example case: maybe people are just calling "saints in our book" too often. easy solution: cache that data and remove the info about seen xy seconds ago - nobody needs that. info in an hourly scale would be enough here).
second: use munin and other tools to compare performance to see, if a specific optimization really changed something. in my app, I log the request time (the time inside the mod_perl handler) to a logfile, and let munin make a graph out of it. nice to see how that changes over time, and there's nothing better than doing an optimization and see the chart going down. and it helps to estimate future optimizations.
I don't know the current code in use, and I don't know how I can get to it. I asked for it. I would offer to at least look into it if I can see myself if there are any good places for optimization. But that's where I'm stuck. perlmonks.org is closed to the outside. So I am not able to help as I would like to.