MonetDB is becoming more and more stable. My current mserver (Aug2009 SP2 release) instance has been up for more than a month. It maintains my database with more than 1.9 billion tuples, has run >20000 of rather complex queries (a few pages of SQL per query) with sometimes more than 20 queries in parallel, and no sign of performance degradation. The actual CPU time of the server has just crossed 100 hours. I would like to thank the dedicated developers who have been building a great system!
Very efficient SQL and XML database management system. Supporting many clients and has an active user and development community.