As far as I know the OS handles the low lever memory management. The ephemeral database uses the allocated from the OS ram. Depending on your OS configuration one may have or not have a swap. However for the database app (daemon, service) this may be transparent. Either there is some free ram to run or there's no ram available.
The other thing is that probably it's not a good idea to rely on swap memory. Not sure there's a point of going that path for performance reasons.
brudgers
I am not an expert. I read a fair bit about databases several years ago. My understanding is many databases handle file IO directly. To facilitate this, the database is stored in a single file. Also, it is common to have the database as the only application running on a computer.
The reason is that caching strategies vary with workload. Operating systems have caching strategies for other workloads.
ahartmetz
I seem to recall reading (and just confirmed) that Oracle can work on whole partitions, don't know about paging. I wouldn't know of any of the open source DBs doing that or having that option. They ~all use multiple filesystem files even.
The other thing is that probably it's not a good idea to rely on swap memory. Not sure there's a point of going that path for performance reasons.