Re: adding a nullable column of type domain w/ check constraint runs checks?

I have a large table that I don't want to lock for more than couple seconds. I want to add a nullable column to the table, the type of the column is a domain with a check constraint.

It appears that the check constraint is being checked for each row, even though the column can be nullable? Is there a way around this?

BEGIN Timing is on.

create domain test_enum numeric check (value > 0); CREATE DOMAIN Time: 1.817 ms

create table test_enum_table (id serial primary key); CREATE TABLE Time: 2.213 ms

insert into test_enum_table select * from generate_series(1, 2000000); INSERT 0 2000000 Time: 4299.000 ms

alter table test_enum_table add column t test_enum; ALTER TABLE Time: 3165.869 ms -- Takes 3 seconds in this test example