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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 table1
AS
SELECT *
FROM (VALUES
(1, 26),
(2, 56),
(3, 12),
(4, 67)) v (inventory_id, test_id);
SELECT 4
CREATE TABLE table2
AS
SELECT *
FROM (VALUES
(12, NULL),
(26, NULL),
(56, NULL),
(67, NULL)) v (test_id, inventory_id);
SELECT 4
SELECT *
FROM table1;
| inventory_id | test_id |
|---|---|
| 1 | 26 |
| 2 | 56 |
| 3 | 12 |
| 4 | 67 |
SELECT 4
SELECT *
FROM table2;
| test_id | inventory_id |
|---|---|
| 12 | null |
| 26 | null |
| 56 | null |
| 67 | null |
SELECT 4
UPDATE table2 t2
SET inventory_id = t1.inventory_id
FROM table1 t1
WHERE t1.test_id = t2.test_id;
UPDATE 4
SELECT *
FROM table2;
| test_id | inventory_id |
|---|---|
| 12 | 3 |
| 26 | 1 |
| 56 | 2 |
| 67 | 4 |
SELECT 4