We need to store apporx 300 GB of data a month. It will be OLTP system. We want to use commodity hardware and open source database. we are willing to sacrifice performance for cost. E.g. a single row search from 2 billion rows table should be returned in 2 sec. ... Good grief. And you didn't post this to some hobby-kit database list, right? Try loading a free Linux distro and typing : man dbopen man hash man btree man mppo man recno I'm sure there's all sorts of free stuff out there that will keep you busy. BTW, as for these primitives, I've been there and done that...Tuxedo too...loads of fun. But then I've done Control Data IPF2 on Cyber 180/830 and lived to tell about it. -- //www.freelists.org/webpage/oracle-l