Re: BUG #15710: ADD COLUMN IF NOT EXISTS adds constraint anyways

PG Bug reporting form <noreply@postgresql.org> writes:
> If I want to add a column to a table which and the column may or may not
> already exist, the specified column constraint like UNIQUE is added every
> time the command is issued, regardless if the column gets added or not.

Yeah, this is the same thing previously reported at

https://www.postgresql.org/message-id/flat/152509815280.19803.16118194452213577808%40wrigleys.postgresql.org

We haven't got further than sketching a design for a fix :-(

            regards, tom lane