On some OSes, it's possible to extract information from the OS's cache and combine it with details of the PostgreSQL's cache. If available, this provides a more comprehensive view of the data than looking just at the database side of things. Projects viewing this data are still in the early stages; however, some example implementations include:
- http://www.kennygorman.com/wordpress/?p=250: Python script showing PostgreSQL objects in Linux memory.
- http://pgfoundry.org/projects/pgfincore/:%20pgfincore: PgFincore provides this data directly inside the database itself, where you might combine it with data from pg_buffercache. Currently, this targets Linux and PostgreSQL 8.4.
