Postgres 14

By using db<>fiddle, you agree to license everything you submit by Creative Commons CC0.

Help with an interesting Postgres question: Why isn't an Index Only Scan used on a partition accessed via the parent table?.

create table tabelle_1 (id int, ks int, x int, y int);
insert into tabelle_1
VALUES
  (1, 26, 52, 13),
  (2, 11, 51, 12),
  (3, 8, 53, 11);
3 rows affected

create function xy_funktion(p_x int, p_y int)
  returns table (v1 int, v2 int, v3 int)
as
$$
  select p_x * 10, p_y * 100, p_x + p_y
  from generate_series(1, 2);
$$
language sql;  
Select t1.id, f.v1, f.v2, f.v3, t1.ks
from tabelle_1  t1
   cross join xy_funktion (t1.x, t1.y) as f    
order by t1.id;


id
v1
v2
v3
ks


1
520
1300
65
26

1
520
1300
65
26

2
510
1200
63
11

2
510
1200
63
11

3
530
1100
64
8

3
530
1100
64
8

id	v1	v2	v3	ks
1	520	1300	65	26
1	520	1300	65	26
2	510	1200	63	11
2	510	1200	63	11
3	530	1100	64	8
3	530	1100	64	8