Martijn van Oosterhout <kleptog@svana.org> writes:
> [ concerning handling a change in a single datatype's representation ]
> 1. Under old system, munge the system catalog to add code for new inet
> type with new OID. Probably needs a shared lib (if you could create
> type input/output function with pl/pgsql it would help here).
> 2. Execute ALTER COLUMN TYPE USING to switch to the new type.
> 3. Shutdown old server
> 4. Complete catalog changes
> 5. Startup new version
Probably easier and more flexible just to include both versions of the
datatype in the new release, and tell people they'd better ALTER COLUMN
TYPE sometime before updating to release N+2.
regards, tom lane