On 12th of February, Robert Haas committed patch: Teach ALTER TABLE .. SET DATA TYPE to avoid some table rewrites.   When the old type is binary coercible to the new type and the using clause does not change ...

Finally, on 25th of October, Tom Lane committed patch which does: Allow new values to be added to an existing enum type.   After much expenditure of effort, we've got this to the point where the performance penalty is pretty minimal in typical cases.   Andrew ...

On 26th of September, Peter Eisentraut committed patch which adds: Add ALTER TYPE ... ADD/DROP/ALTER/RENAME ATTRIBUTE   Like with tables, this also requires allowing the existence of composite types with zero attributes.   reviewed by KaiGai Kohei