Some more thoughts on implementing this feature...
I'm not sure if the regular idlcachesize parameter is appropriate here, but it makes sense to start with that for experimenting and introduce a new config parameter later if it's needed. Once the LRU limit is reached, flush the oldest cache blocks out to the database before freeing/re-using them.
--Quanah
-- Quanah Gibson-Mount Principal Software Developer ITSS/Shared Services Stanford University GnuPG Public Key: http://www.stanford.edu/~quanah/pgp.html
"These censorship operations against schools and libraries are stronger than ever in the present religio-political climate. They often focus on fantasy and sf books, which foster that deadly enemy to bigotry and blind faith, the imagination." -- Ursula K. Le Guin