I think the switch back is because VMware has their own (relatively new) customized PostgreSQL (vPostgres http://www.vmware.com/products/application-platform/vf

I think the switch back is because VMware has their own (relatively new) customized PostgreSQL (vPostgres http://www.vmware.com/products/application-platform/vfabric-postgres/overview.html http://www.vmware.com/products/application-platform/vfabric-...) that they sell/support.