set client_min_messages = 'warning'; create table data1 ( id serial primary key, data text ); create unique index idx_data1_uq on data1 (data); create index idx_data1_rand on data1 (id, data); create table data2 ( id serial primary key, data text, -- old_id integer references data1, constraint uq_data2 unique (data) ); create index idx_data2_rand on data2 (id, data);