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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
card_id | school_id | student_id | student_card_order |
---|---|---|---|
2 | 1 | 1 | 1 |
1 | 1 | 1 | 2 |
4 | 1 | 2 | 1 |
3 | 1 | 2 | 2 |
6 | 1 | 3 | 1 |
5 | 1 | 3 | 2 |
8 | 1 | 4 | 1 |
7 | 1 | 4 | 2 |
10 | 2 | 5 | 1 |
9 | 2 | 5 | 2 |
11 | 2 | 6 | 1 |
12 | 3 | 7 | 1 |
SELECT 12
card_id | school_id | student_id | student_card_order | school_card_order |
---|---|---|---|---|
2 | 1 | 1 | 1 | 4 |
4 | 1 | 2 | 1 | 3 |
6 | 1 | 3 | 1 | 2 |
8 | 1 | 4 | 1 | 1 |
10 | 2 | 5 | 1 | 2 |
11 | 2 | 6 | 1 | 1 |
12 | 3 | 7 | 1 | 1 |
SELECT 7
card_id | school_id | student_id | student_card_order | school_card_order |
---|---|---|---|---|
2 | 1 | 1 | 1 | 7 |
1 | 1 | 1 | 2 | 8 |
4 | 1 | 2 | 1 | 5 |
3 | 1 | 2 | 2 | 6 |
6 | 1 | 3 | 1 | 3 |
5 | 1 | 3 | 2 | 4 |
8 | 1 | 4 | 1 | 1 |
7 | 1 | 4 | 2 | 2 |
10 | 2 | 5 | 1 | 2 |
9 | 2 | 5 | 2 | 3 |
11 | 2 | 6 | 1 | 1 |
12 | 3 | 7 | 1 | 1 |
SELECT 12
card_id |
---|
8 |
6 |
11 |
10 |
12 |
SELECT 5
card_id | school_id | student_id | student_card_order | school_card_order |
---|---|---|---|---|
8 | 1 | 4 | 1 | 1 |
7 | 1 | 4 | 2 | 2 |
11 | 2 | 6 | 1 | 1 |
10 | 2 | 5 | 1 | 2 |
12 | 3 | 7 | 1 | 1 |
SELECT 5