Re: Missing constraint when duplicated unique index ?

test=# set client_min_messages = debug; -- only to get toast table name

test=# CREATE TABLE table_test (
    foo text NOT NULL,
    CONSTRAINT test_pk PRIMARY KEY (foo),
    CONSTRAINT test_uq UNIQUE (foo)
);
building index "pg_toast_29368336_index" on table "pg_toast_29368336" serially
CREATE TABLE / PRIMARY KEY will create implicit index "test_pk" for table "table_test"
building index "test_pk" on table "table_test" serially

test=# select relname, relkind from pg_class where relname ~ 'pg_toast_29368336|pg_toast_29368336_index|test_pk|table_test';
         relname         | relkind
-------------------------+---------
 pg_toast_29368336       | t
 pg_toast_29368336_index | i
 table_test              | r
 test_pk                 | i
(4 rows)

test=# select conname, contype, conrelid::regclass from pg_constraint where conrelid::regclass::text ~ 'table_test|pg_toast_29368336';
 conname | contype |  conrelid
---------+---------+------------
 test_pk | p       | table_test
(1 row)

test=# select indexrelid::regclass, indrelid::regclass, indisunique from pg_index
where indrelid::regclass::text ~ 'table_test|pg_toast_29368336'
            indexrelid            |          indrelid          | indisunique
----------------------------------+----------------------------+-------------
 pg_toast.pg_toast_29368336_index | pg_toast.pg_toast_29368336 | t
 test_pk                          | table_test                 | t
(2 rows)

I know Table and Toast are separate relations but there are two indexes, so the question is,
will there be any additional check when insert/update because there exists a second unique index ?

Is it intentional to have this unique index without a related constraint ?

regards

Marcos