This is (part) of a white paper prepared by Gavin Sherry and Liam O'Duibhir for Fujitsu Australia Software Technology. Fujitsu specific material has been removed and the idea is that the copy can be tidied up and presented as a whitepaper on postgresql.org or printed for conferences etc. Content can also be repurposed for other more specific whitepapers or marketing material. If you have any questions, contact Gavin Sherry (gavin@alcove.com.au).