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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?.
| date | value | grp | counter |
|---|---|---|---|
| 2018-12 | 0 | 1 | 3 |
| 2018-11 | 1 | 1 | 2 |
| 2018-10 | 1 | 1 | 1 |
| 2018-09 | 1 | 1 | 0 |
| 2018-08 | 0 | 2 | 2 |
| 2018-07 | 1 | 2 | 1 |
| 2018-06 | 1 | 2 | 0 |
| 2018-05 | 0 | 3 | 1 |
| 2018-04 | 1 | 3 | 0 |
| 2018-03 | 0 | 4 | 0 |
| 2018-02 | 0 | 5 | 1 |
| 2018-01 | 1 | 5 | 0 |