"Peter J. Holzer" <hjp-pgsql@xxxxxx> writes: > As you can see, adding the primary key takes just as much time as > creating the unique index. So it doesn't look like PostgreSQL is able to > take advantage of the existing index (which makes sense since it still > has to create a new index). No, but you can attach an existing unique index as a primary key: regression=# create table t1 (f1 int not null); CREATE TABLE regression=# create unique index t1_f1 on t1(f1); CREATE INDEX regression=# alter table t1 add primary key using index t1_f1; ALTER TABLE If you build the unique index concurrently, this needn't involve much downtime. regards, tom lane
