Stephan Szabo <sszabo(at)megazone23(dot)bigpanda(dot)com> writes:
> SET DEFAULT just sets the default up but also doesn't modify the actual rows
> stored on disk. Presumably SET DEFAULT should probably do the update,
No, it shouldn't; the existing behavior is per spec. SET DEFAULT just
changes the default for future insertions, it's not supposed to touch
the present table contents.
ALTER TABLE ADD COLUMN with a default clause *is* supposed to fill all
rows of the table with the default. The reason we reject it is we don't
have that behavior implemented.
regards, tom lane