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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
INSERT 0 3
| my_date | prev_month |
|---|---|
| 2019-04-01 | 2019-03-01 |
| 2019-05-01 | 2019-04-01 |
| 2019-01-01 | 2018-12-01 |
SELECT 3