Many databases wire their memory because swapping would be operationally catastrophic and they position themselves as being designed for "mission-critical" appl

Many databases wire their memory because swapping would be operationally catastrophic and they position themselves as being designed for "mission-critical" applications. I've seen databases get swapped a couple times many years ago, it isn't pretty. Databases have a roughly fixed memory footprint, so sensible configurations don't contribute to memory pressure experienced by other processes. Database implementations are capable of swapping most of their address space themselves, independent of and better than the OS -- it is a large part of their function. As such, optimization is heavily dependent on both memory and storage being physical. This being true is precondition for most architectural macro-optimizations to work.