Last week, the PostgreSQL community announced the general availability of PostgreSQL 8.4. This is another great release from the community with a number of great new features such as analytical functions and even deeper security. All worthy features to be highlighted as the headline of the release, but the true headline feature is not even part of the core engine. In conjunction with the 8.4 release, Bruce Momjian is in the process of releasing pg_migrator as an external project that allows users to upgrade their database in place. While most databases has had this functionality for years, it is something that PostgreSQL has lacked and in my opinion has held PostgreSQL back from deeper enterprise adoption. Previously, to move to a new major release, users would need to export their data from the old version and then import it into the new version. This works well when the database is small, but if the database is large, it could mean hours or days of downtime to upgrade the database along with at least double the storage to hold the two copies. This is completely unacceptable to  enterprises that need to maintain a 24×7 environment. I believe that pg_migrator has cleared on the the few major technical hurdles preventing PostgreSQL from widespread commercial adoption.