On 28th of March 2018, Andrew Dunstan committed patch: Fast ALTER TABLE ADD COLUMN with a non-NULL default Currently adding a column to a table with a non-NULL default results in a rewrite of the table. For large tables this can be both ...

On 4th of December Peter Eisentraut committed patch by Pavel Stehule (with Peters tweaks) which adds default values for function arguments: Default values for function arguments   Pavel Stehule, with some tweaks by Peter Eisentraut