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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 12
| session_id | step | device |
|---|---|---|
| 351acc | step1 | mobile |
| 351acc | step2 | mobile |
| 351acc | step3 | mobile |
| 351acc | step4 | mobile |
| 350bca | step1 | desktop |
| 350bca | step2 | desktop |
| 350bca | step3 | desktop |
| 350bca | step4 | desktop |
| 111bca | step1 | 1st notnull |
| 111bca | step2 | 1st notnull |
| 111bca | step3 | not this |
| 111bca | step4 | and not this |
SELECT 12