Is primary key column included at the end of a secondary index - postgresql

Question

Given these tables
Foo
id (PK)
name
updated
Bar
foo_id (FK)
name
updated
And this query:
SELECT *
FROM Foo as f
JOIN Bar as b
ON f.id=b.foo_id
WHERE b.name = 'Baz' AND f.name = 'Baz'
ORDER BY f.updated ASC, f.id ASC
LIMIT 10
OFFSET 10
Are these appropriate indexes to add - in MySql InnoDB the primary key column is automatically added to the end of a secondary index. What is the case with Postgres?
CREATE INDEX foo_name_id_idx ON foo(name, id)
CREATE INDEX bar_name_id_idx ON bar(name, id)

Answer 1

PostgreSQL does not make the distinction between primary and secondary indexes, and the primary key index is no different from other indexes. So the primary key is not added to other indexes, and there is no point in doing that unless you have a special reason for it.
Depending on which of the conditions are selective, there are three possible strategies:
If the condition on bar.name is selective, use bar as the driving site:
CREATE INDEX ON bar (name);
-- foo.id is already indexed
If the condition on foo.name is selective:
CREATE INDEX ON foo (name);
CREATE INDEX ON bar(foo_id); -- for a nested loop join
If none of the conditions are selective:
/* here the "id" is actually at the end of the index,
but that is just because it appears in ORDER BY */
CREATE INDEX ON foo (name, updated, id); -- for the ORDER BY
CREATE INDEX ON bar (foo_id); -- for a nested loop join