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Help with an interesting Postgres question: Why isn't an Index Only Scan used on a partition accessed via the parent table?.
CREATE TABLE departamentos (
id_departament int PRIMARY KEY
);
CREATE TABLE employees (
id_user int,
id_departament int REFERENCES departamentos (id_departament)
);
INSERT INTO departamentos VALUES (1),(2);
INSERT INTO employees VALUES (100,1),(83,1),(42,1),(88,2),(99,2);
CREATE TABLE
CREATE TABLE
INSERT 0 2
INSERT 0 5
SELECT d.id_departament, count(e.id_departament) AS TOTAL
FROM departamentos d
JOIN employees e ON e.id_departament = d.id_departament
GROUP BY d.id_departament
HAVING count(e.id_departament) > 2
| id_departament | total |
|---|---|
| 1 | 3 |
SELECT 1