On Tue, Aug 19, 2014 at 3:10 PM, Joe Van Dyk <j...@tanga.com> wrote: > 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 > > Also:
alter table test_enum_table add column t1 numeric check (t1 > 0); ALTER TABLE Time: 140.185 ms which is much more reasonable.
