so what I am thinking is moving to latest 1.7 and use merge some of the experimented branch. is the reference you sent is the only class I need to change or is there anything else?
From what I recall, there are caches in other places, but we'd need to follow some of the reference chains to see which ones are actually the ones that are heavily in use in your context.
As a first step, I'd recommend trying with "vanilla" 1.7.2 first and, if the memory footprint is still too large, trying the patch we discussed. If that doesn't help, we can always come back and look for other options ;-)
ap
