I've come across an unexpected ERROR during validation of FK constraint in PG 18beta1. The same works in PG 17:
drop table if exists fk; drop table if exists pk; create table pk(i int primary key) partition by range (i); create table pk_1 partition of pk for values from (0) to (1); create table pk_2 partition of pk for values from (1) to (2); insert into pk values (0), (1); create table fk(i int); insert into fk values (1); -- Works if the FK constraint is created as valid. --alter table fk add foreign key(i) references pk; -- Fails if the FK constraint is created as NOT VALID and validated -- afterwards. alter table fk add foreign key(i) references pk not valid; alter table fk validate constraint fk_i_fkey; -- Antonin Houska Web: https://www.cybertec-postgresql.com
