By the way, in regards to Durus vs Pickle, I found Durus outperformed
Pickle in all critical areas in my app, which is why we're still using
it. Pickle had the same memory use and speed, but it added 30 seconds
to the application startup.  Compressing the Pickle file shrunk it by
80% (40 MB to 8 MB) but had no effect on memory size or speed.

Lowering the Durus cache to a measly 20 objects and making Chemical
Persistent again (which required disabling .__slots__) brought the
memory up to 190 MB (from 121), so that's not an option.

The Chemical object has 153 slots, by the way, so slots are performing
well even with a large number of attributes.

--
Mike Orr