With index scans to use an intermediate in-memory bitmap and improved buffer cache and performance for partitioned tables, PostgreSQL 8.1 will be sure to make us feel good we have no idea what these things actually do! On the other hand, the addition of features: user roles on shared objects, the separation of roles from user/group distinctions, share level row locking, auto-indexes on MAX() and MIN(),two part commits, and the inclusion of the all to familiar contributed module for pg_autovacuum into the main sources, are all features we will love and understand.

Again with this upgrade a pg_dump and restore is required for the upgrade.